US20220000705A1 - Compression garment compliance - Google Patents

Abstract

Determining whether a compression garment is worn by a wearer of the garment by analyzing a pressure signal waveform indicative of a fluid pressure in an inflatable and deflatable bladder of the compression garment. Variance detected in the pressure signal waveform during the analysis is indicative of a change in condition of the compression garment. In one aspect the change in condition is verified using confirmatory analysis. In another aspect, the variance is one of a pressure rise and a pressure impulse. In yet another aspect, the variance is an oscillating amplitude as a function of time representative of a pulse of the wearer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims priority from U.S. Provisional Patent Application Ser. No. 62/239,566, filed Oct. 9, 2015, entitled “Compression Garment Compliance,” U.S. Provisional Patent Application Ser. No. 62/239,527, filed Oct. 9, 2015, entitled “Determining a Configuration of a Compression Garment,” U.S. Provisional Patent Application Ser. No. 62/239,493, filed Oct. 9, 2015, entitled “Determining a Configuration of a Compression Garment,” and U.S. Provisional Patent Application Ser. No. 62/329,233, filed Apr. 29, 2016, entitled “Determining a Configuration of a Compression Garment.” The entire contents of the above-identified applications are expressly incorporated herein by reference, including the contents and teachings of any references contained therein.
BACKGROUND
• Intermittent pneumatic compression (IPC) systems include devices used to apply pressurized fluid, such as air, to a limb of a patient or wearer. In some instances, pressurized air is applied to the lower limb of a patient at risk for the formation of deep vein thrombosis (DVT). An IPC system typically includes a pumping unit to manage pressurization of the fluid, a tubing set to extend the delivery of fluid beyond the pumping unit, and a compression garment which is wrapped around the patient's limb and contains the pressurized fluid. The IPC system intermittently pressurizes the garment to apply therapeutic compression to the patient's limb, moving blood from that area of the limb. The effectiveness of such IPC systems for DVT prophylaxis, however, depends on the patient's adherence to a prescribed treatment protocol including the IPC system.
SUMMARY
• In an aspect, the present disclosure is directed to systems and methods of monitoring a wearer's compliance with a compression treatment regimen for use of a compression system. In another aspect, the present disclosure is directed to systems and methods of determining whether a compression garment is applied to a limb of a wearer.
• In one aspect, a compression device controller includes a memory device, one or more processors coupled to the memory device, and computer-executable instructions embodied on a computer readable storage medium. The memory device is configured for storing monitored parameters. The computer-executable instructions include instructions for causing the one or more processors to direct the flow of fluid from a pressurized fluid flow source to inflate and deflate an inflatable bladder of a compression garment. The compression garment is configured to be wrapped around a limb of a wearer of the garment. Also included are instructions for causing the one or more processors to receive pressure signals indicative of fluid pressure in the inflatable bladder from a pressure sensor communicatively coupled to the bladder. The one or more processors, when caused by the instructions, process the received pressure signals during at least one of inflation and deflation of the inflatable bladder. The pressure signals are used to detect variance in the signals indicative of a change in condition of the compression garment. The instructions also cause the one or more processors to change a state of at least one of the monitored parameters in the memory device in response to detecting variance in the received pressure signals. The changed state of the monitored parameter is representative of the change in condition of the compression garment.
• In another aspect, a computer-implemented method includes computer-executable instructions executing on one or more processors controlling a pressurized fluid flow source through a cycle of operation in which at least one inflatable bladder of a compression garment configured to be wrapped around a limb of a patient is inflated and deflated. The one or more processors receive pressure signals indicative of fluid pressure in the bladder from a pressure sensor communicatively coupled to the bladder. Computer-executable instructions executing on the one or more processors detect variance in the received pressure signals indicative of a change in condition of the compression garment during the inflation and deflation of the bladder. Computer-executable instructions executing on the one or more processors also change a state of at least one monitored parameter stored in a memory device in response to detecting variance in the received pressure signals. The memory device is coupled to the one or more processors and the changed state of the monitored parameter is representative of the change in condition of the compression garment.
• In yet another aspect, a system includes a compression garment and a controller. The compression garment includes at least one inflatable and deflatable bladder and is securable about a limb of a wearer. The controller includes a memory device, one or more processors coupled to the memory device, and computer-executable instructions embodied on a computer readable storage medium. The memory device is configured for storing monitored parameters. The computer-executable instructions include instructions for causing the one or more processors to direct the flow of fluid from a pressurized fluid flow source to inflate and deflate the bladder of the compression garment. Also included are instructions for causing the one or more processors to receive pressure signals indicative of fluid pressure in the bladder from a pressure sensor communicatively coupled to the bladder. The one or more processors, when caused by the instructions, process the received pressure signals during at least one of inflation and deflation of the inflatable bladder. The pressure signals are used to detect variance in the signals indicative of a change in condition of the compression garment. The instructions also cause the one or more processors to change a state of at least one of the monitored parameters in the memory device in response to detecting variance in the received pressure signals. The changed state of the monitored parameter is representative of the change in condition of the compression garment.
• Embodiments can include one or more of the following advantages.
• In some embodiments, compliance monitoring of a compression system is performed using a signal indicative of pressure in an inflatable bladder of a compression garment, providing a real time indication of a wearer's compliance with use of the compression garment. This can, for example, provide a robust indication of compliance while reducing the burden on caregivers to track compliance.
• Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a compression system including a compression garment and a controller.
• FIG. 2 is a schematic representation of the compression system ofFIG. 1, including a schematic of a pneumatic circuit.
• FIG. 3 is a schematic representation of another exemplary compression system ofFIG. 1, including a schematic of a pneumatic circuit.
• FIG. 4 is a graphical representation of a pressure profile produced by the compression system ofFIG. 1 when the compression garment is in a wrapped configuration on a leg form, simulating a limb of a wearer.
• FIG. 5 is a graphical representation of a pressure profile produced by the compression system ofFIG. 1 when a compression garment of the system is in an unwrapped configuration and away from a leg form, simulating a limb of a wearer.
• FIG. 6 is a graphical representation of the manifold pressure signals of the compression system ofFIG. 1, the manifold pressure signals corresponding to manifold pressure signals for the wrapped and unwrapped compression garment configurations inFIGS. 4 and 5, respectively.
• FIG. 7 is a flow diagram of a method of compliance monitoring using the compression system ofFIG. 1.
• FIGS. 8 and 9 are flow diagrams of exemplary implementations of the compliance monitoring method ofFIG. 7.
• FIG. 10 is a graphical representation of polynomial curve fit lines of the pressure in the manifold during an inflation phase of a bladder of the compression garment in both the wrapped and unwrapped configurations.
• FIG. 11 is a graphical representation of a pressure profile produced by the compression system ofFIG. 1 when the compression garment is in a wrapped configuration on a limb of a wearer.
• FIG. 12 is graphical representation of a pressure profile produced by the compression system ofFIG. 1 when the compression garment is in an unwrapped configuration and away from a limb of a wearer.
• FIGS. 13 and 14 are flow diagrams of methods of compliance monitoring using the compression system ofFIG. 1.
• FIGS. 15A-15C are graphical representations of another pressure profile produced by the compression system ofFIG. 1 when the compression garment is in a wrapped configuration on a limb of a wearer.
• FIG. 16 is graphical representation of another pressure profile produced by the compression system ofFIG. 1 when the compression garment is in an unwrapped configuration and away from a limb of a wearer.
• FIGS. 17A and 17B are graphical representations of another pressure profile produced by the compression system ofFIG. 1 when the compression garment is in a wrapped configuration on a limb of a wearer.
• FIGS. 18-23C are flow diagrams of methods of compliance monitoring using the compression system ofFIG. 1.
• FIGS. 24 and 25 are graphical representations of another pressure profile produced by the compression system ofFIG. 1 when the compression garment is in a wrapped configuration on a limb of a wearer.
• Corresponding reference characters indicate corresponding parts throughout the drawings.
DETAILED DESCRIPTION
• As used herein, the terms “proximal” and “distal” represent relative locations of components, parts and the like of a compression garment when the garment is worn. For example, a “proximal” component is disposed most adjacent to the wearer's torso, a “distal” component is disposed most distant from the wearer's torso, and an “intermediate” component is disposed generally anywhere between the proximal and distal components. Further, as used herein, the terms “wrapped” and “unwrapped” define conditions of the garment where the garment is properly applied to the wearer's limb (wrapped) and where the garment is removed from the wearer's limb (unwrapped).
• Referring toFIGS. 1-3, acompression system1 includes acompression garment10 for applying sequential compression therapy to a limb of a wearer and acontroller5 having one ormore processors7 and computer executable instructions embodied on a computerreadable storage medium33, the computer executable instructions including instructions for causing the one or more processors to control operation of thecompression system1. Thecompression garment10 includes a distalinflatable bladder13a,an intermediateinflatable bladder13b,and a proximalinflatable bladder13c.Thecompression garment10 can be fastened around the wearer's limb and in one embodiment is adjustable to fit limbs of different circumferences.
• As described in further detail below, thecontroller5 controls operation of thecompression system1 to perform an inflation cycle, in which theinflatable bladders13a,13b,13care inflated to apply pressure to the wearer's limb to establish a gradient pressure applied to the wearer's limb by theinflatable bladders13a,13b,13cof thecompression garment10 during one or more compression cycles. As also described in further detail below, for purposes of this description, each therapeutic compression cycle includes inflation phases for all threebladders13a,13b,13c,a decay phase forbladders13aand13b,and a vent phase for all threebladders13a,13b,13c.The end-of-cycle pressure of eachbladder13a,13b,13cis the pressure in eachbladder13a,13b,13cprior to initiation of the vent phase of therespective bladder13a,13b,13c.As will be explained in greater detail below, thecontroller5 determines, based at least in part on a measured pressure of one or more of theinflatable bladders13a,13b,13b,whether or not thecompression garment10 is applied to (i.e., in a wrapped configuration around) a wearer's limb and, in some embodiments, provides an indication of the determination (e.g., by incrementing a timer, by pausing a timer, by providing an audible alarm, and/or by providing a visual indication on a graphical user interface). Determining whether thecompression garment10 is being worn (i.e., in a wrapped configuration around a wearer's limb) provides a compliance monitoring function which enables thecompression system1 to track when the garment is being properly used to achieve a prescribed treatment. As also described in further detail below, thecontroller5 can control operation of thecompression system1 to perform an inflation cycle, in which theinflatable bladders13a,13b,13care inflated to apply pressure to the wearer's limb to establish, for example, a gradient pressure applied to the wearer's limb by theinflatable bladders13a,13b,13cof thecompression garment10 during one or more compression cycles.
• Thecompression garment10 is a thigh-length sleeve positionable around the leg of the wearer, with thedistal bladder13aaround the wearer's ankle, theintermediate bladder13baround the wearer's calf, and theproximal bladder13caround the wearer's thigh. It will be understood by one of ordinary skill in the art thatcompression garment10 may be a knee-length sleeve, a foot garment, and the like without departing from the scope of the invention. Theinflatable bladders13a,13b,13cexpand and contract under the influence of fluid (e.g., air or other fluids) delivered from a pressurized fluid source21 (e.g., a pump or compressor) in electrical communication with thecontroller5. The pressurizedfluid source21 delivers pressurized fluid (e.g., air) to theinflatable bladders13a,13b,13cthroughtubing23.
• Referring toFIG. 2, eachinflatable bladder13a,13b,13cis in fluid communication with arespective valve25a,25b,25c.Apressure sensor27 is in communication (e.g., fluid communication) with a manifold29 to measure a signal indicative of pressure in themanifold29. Fluid communication between the manifold29 and the respectiveinflatable bladders13a,13b,13ccan be controlled through control of the position of therespective valves25a,25b,25c(e.g., through activation and/or deactivation of therespective valves25a,25b,25c). Thepressure sensor27 is in electrical communication with thecontroller5 such that thecontroller5 receives from thepressure sensor27 signals indicative of the pressure of the manifold29 and/or one or more of theinflatable bladders13a,13b,13cin fluid communication with the manifold29 as a result of the positions of therespective valves25a,25b,25c.If only onebladder13a,13bor13cis in fluid communication with the manifold29, the signal received from thepressure sensor27 is indicative of the pressure of therespective bladder13a,13b,13cin fluid communication with the manifold29. For example, thepressure sensor27 provides a signal indicative of the pressure in theinflatable bladder13awhenvalve25ais open andvalves25b,25care closed. Similarly, thepressure sensor27 provides a signal indicative of the pressure in thebladder13bwhen thevalve25bis open and thevalves25aand25care closed. Likewise, thepressure sensor27 provides a signal indicative of the pressure in theinflatable bladder13cwhen thevalve25cis open and thevalves25aand25bare closed. Avent valve25dis actuatable to control fluid communication between the manifold29 and avent port15, which vents to ambient atmosphere. Allbladders13a,13b,13ccan be vented using thevent valve25d.
• Eachvalve25a,25b,25cis a 2-way/2-position, normally open, solenoid valve. Eachvalve25a,25b,25cincludes two ports and is actuatable to place an inlet port in fluid communication with a bladder port in a first, open position. Eachvalve25a,25b,25cis further actuatable to shut off fluid communication between the inlet port and the bladder port. The inlet port of eachvalve25a,25b,25cis in fluid communication with the pressurizedfluid source21 and the manifold29. The bladder port of eachvalve25a,25b,25cis in fluid communication with a respectiveinflatable bladder13a,13b,13c.
• Any one of thebladders13a,13b,13ccan be placed in fluid communication with the pressurizedfluid source21 and the manifold29 by therespective valve25a,25b,25cto deliver pressurized fluid to thebladder13a,13b,13c.After thebladder13a,13b,13cis inflated, therespective valve25a,25b,25ccan be closed to hold the fluid in therespective bladder13a,13b,13c.Thus, thebladders13a,13b,13cof thecompression garment10 can be individually inflated by opening therespective valve25a,25b,25cand closing theother valves25a,25b,25cso that only the onebladder13a,13b,13cassociated with the openedvalve25a,25b,25cis in fluid communication with the pressurizedfluid source21 and the manifold29.
• Thevent valve25dis also a 2-way/2-position, normally open, solenoid valve. Thevent valve25dincludes two ports and is actuatable to place an inlet port in fluid communication with avent port15 in a first position. The vent inlet port is in fluid communication with avent port15 in a first position. Thevent valve25dis further actuatable to shut off fluid communication between the inlet port and thevent port15. The inlet port ofvent valve25dis in fluid communication with the pressurizedfluid source21 and the manifold29. Thevent port15 of thevent valve25dis in fluid communication with ambient atmosphere.
• It should be appreciated that thevalves25a,25b,25c,25dcould be other types and have other arrangements within thecompression system1 without departing from the scope of the present disclosure. For example, referring toFIG. 3, the valves may bevalves35a,35b,35c,which are 3-way/2-position solenoid valves and are actuatable to control the pressure inbladders13a,13b,13cwithout a vent valve.
• With reference again toFIG. 2, the computer executable instructions embodied on the computerreadable storage medium33 include instructions to cause the one ormore processors7 to pressurize (e.g., inflate) theinflatable bladders13a,13b,13cto provide cyclical therapeutic compression pressure to a wearer's limb. For example, the computer executable instructions embodied on the computerreadable storage medium33 include instructions to cause the one ormore processors7 to control the pressurizedfluid source21 and/or thevalves25a,25b,25c,25dto pressurize theinflatable bladders13a,13b,13cto therapeutic compression pressures for a predetermined amount of time to move the blood in the limb from regions underlying theinflatable bladders13a,13b,13c.The length of time thebladder13a,13bis held at the compression pressure is referred to herein as a decay phase. Following the decay phase is a vent phase in which the computer executable instructions include instructions to cause the one ormore processors7 to control the pressurizedfluid source21 and/or thevalves25a,25b,25c,25dto reduce the pressure in theinflatable bladders13a,13b,13cto a lower pressure (e.g., atmospheric pressure).
• Thecompression system1 can determine whether or not thecompression garment10 is applied (i.e., wrapped) to a wearer's limb and, in certain embodiments, can provide an indication of that determination, which can facilitate, for example, tracking the wearer's compliance with a prescribed therapeutic use of thecompression garment10. The computer executable instructions embodied on the non-transitory computerreadable storage medium33 include instructions to cause the one ormore processors7 to analyze pressure signal data received from thepressure sensor27 during a decompression period of a therapeutic cycle of thecompression system1. The computer executable instructions embodied on the non-transitory computerreadable storage medium33 include instructions to cause the one ormore processors7 to determine whether or not the characteristics of the received pressure signal data satisfy one or more conditions indicative of thecompression garment10 positioned on a wearer's limb.
• In an exemplary embodiment, the computer executable instructions cause the one ormore processors7 to receive pressure signal data from thepressure sensor27. The computer executable instructions can include instructions to cause the one ormore processors7 to process a single waveform representative of the pressures within one or more of thebladders13a,13b,13c.It should be appreciated that the one ormore processors7 may process multiple waveforms without departing from the scope of the present disclosure. By monitoring the pressure signals and corresponding pressure data during, for example, a decompression period of the therapy cycle, the one ormore processors7 can detect certain characteristics on the waveform that are indicative of whether thecompression garment10 is properly wrapped on a wearer's limb or is unwrapped from a wearer's limb. In certain embodiments, during the decompression period, thepressure sensor27 remains (or is intentionally placed) in constant communication (e.g., fluidic and/or mechanical communication) with one or more of thebladders13a,13b,13c.Exemplary static periods include non-therapeutic cycles (e.g., pressures inbladders13a,13b,13cof less than about 25 mmHg), a subset of an initial garment detection period, and/or a venous refill measurement period.
• In an exemplary operation of the embodiment ofFIG. 3, in which 3-way/2-position valves are utilized, the computer-executable instructions embodied on the computerreadable storage medium33 include instructions to cause the one ormore processors7 to control one ormore valves35a,35b,35cfor one or more of aparticular bladder13a,13b,13csuch that a fluidic path is established between thepressure sensor27 and one or more of thebladders13a,13b,13c.
• In an exemplary operation of the embodiment ofFIG. 2, in which 2-way/2-position valves are utilized, the computer-executable instructions embodied on the computerreadable storage medium33 include instructions to cause the one ormore processors7 to open or close thevent valve25dsuch that the manifold29 can no longer vent. One or more of the computer-executable instructions causes the one ormore processors7 to determine whether the signal received from thepressure sensor27 for random pressure impulses and spikes that are expected to occur as the wearer moves (e.g., moving leg, flexing calf, coughing, sneezing, general breathing, etc.). Due to a volume of fluid (e.g., air) that is retained within one or more of thebladders13a,13b,13cand extends to the manifold29, and thus thepressure sensor27, even slight movement causes the bladder to move or change shape and produce a pressure spike in the pressure signal generated bypressure sensor27. Conversely, for acompression garment10 that has been removed from a limb of the wearer, the pressure signal generated bypressure sensor27 is static and devoid of random noise or pressure impulses.
• Referring now toFIG. 4, a representative compression cycle pressure profile is shown for thecompression garment10 in a wrapped configuration around a leg form, which simulates a leg of a wearer. The leg form has a size, shape, and rigidity similar to those of a human leg. Accordingly, for the purpose of analyzing the performance of the algorithms described in this disclosure, the leg form is a suitable analog for a leg of a human wearer. Unless otherwise specified, all data shown herein were acquired in an experimental set-up using a leg form.
• This graph shows signals from an experimental set-up in which pressure sensors are used to measure pressure in theindividual bladders13a,13b,13cand thepressure sensor27 is used to measure pressure in themanifold29. As described in further detail below, using this experimental set-up, the pressures measured in theindividual bladders13a,13b,13care compared to the pressure measured by thepressure sensor27 in themanifold29. It should be appreciated that, in normal use, thecontroller5 receives the signals frompressure sensor27 to control operation of thecompression system1.FIG. 4 shows the correspondence between the manifold pressure measured bypressure sensor27 and the pressure measured by pressure sensors disposed in eachbladder13a,13b,13c.
• A single compression cycle for at least one of thebladders13a,13b,13cincludes an inflation phase, a decay phase, and a vent phase for thebladders13a,13b,and an inflation phase and a vent phase for thebladder13c.Pressure plot402 shows a pressure signal throughout a single therapeutic compression cycle for thedistal bladder13a,pressure plot404 shows a pressure throughout a single therapeutic compression cycle for theintermediate bladder13b,pressure plot406 shows a pressure throughout a single therapeutic compression cycle for theproximal bladder13c,andpressure plot408 shows the manifold pressure measured bypressure sensor27 during each of the aforementioned therapeutic compression cycles. Eachplot402,404,406 includes an initial bladder fill period which defines the inflation phase of the therapeutic compression cycle for therespective bladder13a,13b,13c.Once a respective target pressure is achieved in thebladders13a,13b,inflation is stopped and the pressure in the bladder can be held at or near the target pressure defining the decay phase of the therapeutic compression cycle forbladders13a,13b.After the decay phase, in the case ofbladders13a,13b,or immediately after the inflation phase, in the case ofbladder13c,fluid in eachbladder13a,13b,13cis evacuated from the respective bladder during the vent phase of the therapeutic compression cycle for eachbladder13a,13b,13c.
• At the beginning of the therapeutic compression cycle, thevalves25b,25c,and25dare energized to a closed position. To inflate thedistal bladder13a,pressurized fluid from the pressurizedfluid source21 is delivered to thedistal bladder13avia thevalve25aand thetubing23. Once a target pressure for thedistal bladder13ais achieved, or after a period of time measured bytimer31 after which the target pressure is expected to be achieved, thevalve25ais energized to close, holding the pressurized fluid in thedistal bladder13a.Next theintermediate bladder13bis inflated by de-energizingvalve25bto an open position such that pressurized fluid from the pressurizedfluid source21 flows into theintermediate bladder13b.Once a target pressure for theintermediate bladder13bis achieved, or after a period of time measured by thetimer31 after which the target pressure is expected to be achieved, thevalve25bis energized to close, holding the pressurized fluid in theintermediate bladder13b.Next, theproximal bladder13cis inflated by de-energizingvalve25cto an open position such that pressurized fluid from the pressurizedfluid source21 flows into theproximal bladder13c.Once a target pressure for theproximal bladder13cis achieved, or after a period of time measured by thetimer31, after which the target pressure is expected to be achieved,valves25a,25b,and25dare also de-energized to respective open positions. Theopen vent valve25dallows for the fluid in each of thebladders13a,13b,13cto vent to atmosphere.
• Thecompression system1 has been described as individually inflating eachbladder13a,13b,13csuch that only one bladder is being filled with pressurized fluid at a time. It should be appreciated, however, that thebladders13a,13b,13ccan additionally or alternatively be inflated simultaneously or in any combination with one another. In certain embodiments, the opening and closing ofvalves25a,25b,25c,and25dare timed such that only onebladder13a,13b,13cis in fluid communication with thepressure sensor27 and the manifold29 at a time. This facilitates, for example, the use of thepressure sensor27 to measure a signal indicative of each of the pressure of each of thebladders13a,13b,13c.
• The computer executable instructions embodied on the computerreadable storage medium33 include instructions to cause the one ormore processors7 to receive a measured pressure signal from thepressure sensor27 throughout the therapeutic compression cycle. As thedistal bladder13ais inflated, the one ormore processors7 receive from the pressure sensor27 a signal indicative of pressure in the manifold29, which is representative of the pressure in thedistal bladder13a.In this manner, pressure throughout the inflation phase of thedistal bladder13ais measured, including an end of inflation pressure just beforevalve25ais closed. As theintermediate bladder13bis inflated, the one ormore processors7 receive from the pressure sensor27 a signal indicative of the pressure in the manifold29, which is representative of the pressure in theintermediate bladder13b.Pressure throughout the inflation phase of theintermediate bladder13bis measured, including an end of inflation pressure just beforevalve25bis closed. As theproximal bladder13cis inflated, the one ormore processors7 receive from the pressure sensor27 a signal indicative of the pressure in the manifold29, which is representative of the pressure in theproximal bladder13c.Pressure throughout the inflation phase of theproximal bladder13cis measured, including an end of inflation pressure.
• The computer executable instructions include instructions to cause the one ormore processors7 to determine an end-of-cycle pressure in eachbladder13a,13b,13c.As used herein, the end-of-cycle pressure is the pressure in eachrespective bladder13a,13b,13cprior to the vent phase. Thus, for thebladders13a,13b,the end-of-cycle pressure for eachbladder13a,13bis the pressure in eachbladder13a,13bat the end of the respective decay phase of the therapeutic compression cycle of eachbladder13a,13b.Forbladder13c,the end-of-cycle pressure is the pressure in thebladder13cat the end of the inflation phase of thebladder13c.
• To measure the end-of-cycle pressure, thevalves25a,25b,25care sequentially toggled open and closed after theproximal bladder13cis inflated to its target pressure to measure an end-of-cycle pressure in each of thebladders13a,13b,13c(FIG. 4). Because thevalve25cis open from having just inflated theproximal bladder13c,the end of cycle pressure for theproximal bladder13cis measured first. As will be understood from viewing the pressure profile inFIG. 6, the end of inflation pressure and the end of cycle pressure for theproximal bladder13care the same because the proximal bladder does not undergo a decay phase.Valve25ccan be toggled off and then toggled back on at the end of the compression cycle of theproximal bladder13c.The one ormore processors7 toggleopen valve25aandclose valve25cto measure an end of cycle pressure for thedistal bladder13a.The one ormore processors7 toggleopen valve25bandclose valve25ato measure an end of cycle pressure for theintermediate bladder13b.While a specific toggling sequence of thevalves25a,25b,25cis described, it should be appreciated that other toggling sequences of thevalves25a,25b,25care within the scope of the present disclosure. In one embodiment, eachvalve25a,25b,25cis toggled open for about 150 milliseconds (ms) to measure the end of cycle pressure in therespective bladder13a,13b,13c.Thevalves25a,25b,25ccould be toggled open for a shorter or longer period of time. For instance, thevalves25a,25b,25ccould be toggled open for at least about 75 ms. Still other periods of time are envisioned. The pressure readings measured by thepressure sensor27 are stored in thememory33. During operation, the compression cycle is repeated multiple times in succession to complete a compression treatment.
• The computer executable instructions can include instructions to cause the one ormore processors7 to determine a representative line fit using the end of inflation pressure and the end of cycle pressure for at least one of thebladders13a,13b.Using the two pressure points, a line representing the decay phase is produced. The values of this representative line are compared to the end of inflation pressure for abladder13b,13cto determine whether the pressure of the subsequently inflatedbladder13b,13cpotentially rose above the pressure of the previously inflatedbladder13a,13bat any point during the compression cycle.
• Referring toFIG. 5, a representative compression cycle pressure profile for an unwrapped configuration of thecompression system1 is illustrated. Operation of thecompression system1 to produce the pressure profile ofFIG. 5 is identical to the operation described above for the compression cycle pressure profile ofFIG. 4. The only difference is the pressure signals inFIG. 5 were taken when thecompression garment10 was in the unwrapped configuration. Pressure plots502,504,506 show an actual pressure of thedistal bladder13a,intermediate bladder13b,andproximal bladder13cthroughout a single compression cycle when thegarment10 is in the unwrapped configuration. The pressure signal from thepressure sensor27, which is representative of the pressure in the manifold29 during the therapeutic compression cycle, is also shown inFIG. 5 aspressure plot508.
• Referring toFIG. 6, the pressure signals of the representative compression cycle pressure profiles detected by thepressure sensor27 for the wrapped and unwrapped configurations are plotted together. As will be explained in greater detail below, there are characteristics in the representative compression cycle pressure profiles which distinguish the wrapped and wrapped configurations. For instance, referring toFIG. 5, there is a period (e.g., around 6436 ms) when theintermediate bladder13b(504) pressure exceeds the pressure of thedistal bladder13a(502). Additionally, the pressure in thebladders13a,13b,13cbefore the bladders are inflated (i.e., initial pressure offset when time=0) is slightly higher in the unwrapped configuration. The offset is a result of more residual air being in thebladders13a,13b,13cwhen thegarment10 is removed from the limb. Applicant believes this to be because the unwrapped sleeve is less constrained, thereby less evacuative force is applied to expel the residual air (i.e. the sleeve is able to remain “puffed out” thus appearing as though it is smaller in volume). Without wishing to be bound by theory, it is believed that this offset results from the unwrappedcompression garment10 being less constrained, resulting in less evacuative force being applied to expel residual air. Additionally, the end of inflation pressures forbladders13aand13bin the unwrapped configuration are slightly higher than the end of inflation pressures forbladders13aand13bin the wrapped configuration. The reverse condition is true for theproximal bladder13cwhere the end of inflation pressure for the wrapped configuration is slightly higher than the end of inflation pressure for the unwrapped configuration. Another differentiating characteristic is that there is less differential between the end of inflation pressures in the distal andintermediate bladders13a,13bfor the unwrapped configuration than for the wrapped configuration.
• The computer executable instructions embodied on the computerreadable storage medium33 include instructions to cause the one ormore processors7 to model the pressure signals from thepressure sensor27 in both the wrapped and unwrapped configurations. In an embodiment, the pressure signal from the inflation phase of thedistal bladder13ain the wrapped configuration is modeled by a best fit line. For example, the models are best fit lines generated by simple linear regression.
• Analysis of the pressure signal data using the best fit line can provide an indication of whether thebladder13ais in a compliant wrapped configuration, or a non-compliant unwrapped configuration when compression therapy is being applied. The difference between the best fit line and the observed pressure signals is mathematically quantifiable as a means squared error (MSE) value. In this instance, the MSE value is an indicator of the degree of curvature of the observed pressure trend over a given interval such as inflation of a bladder of thecompression garment10. Thus, a larger MSE value indicates that the curve fit data has a larger curvature, and a low MSE value indicates that the curve fit data has a smaller curvature. In an embodiment, the plot for the wrapped configuration is generally straighter (i.e., more nearly conforming to the corresponding best fit line) than the plot for the unwrapped configuration. Mathematically this translates to a smaller MSE value for the curve fit line of the plot for the wrapped configuration. In an embodiment, an MSE value under a predetermined number indicates that the bladder is in the wrapped configuration, while an MSE value greater than or equal to the predetermined number indicates that the bladder is in the unwrapped configuration. It is envisioned that other factors may provide an indication of the configuration of the bladder.
• Referring toFIGS. 7-9, the computer executable instructions embodied on the computerreadable storage medium33 cause the one ormore processors7 to execute amethod740 of determining whether thecompression garment10 is in the wrapped or unwrapped configuration when compression therapy is being applied. The steps set forth inFIG. 7 describe the method of determining whether thecompression garment10 is in the wrapped or unwrapped configuration at a generally high level, andFIGS. 8 and 9 describe the method in greater detail. Reference will be made to all three of the figures in describing the compliance method executed by the one ormore processors7.
• Referring toFIGS. 7 and 8, at the start of thecompliance determination method740, thecompression system1 operates to sequentially inflate and deflate thebladders13a,13b,13cto apply compression treatment to a wearer's limb. The treatment is preferably made according to a predetermined compression regimen, which includes among other things, a prescribed period of time in which the patient should receive the treatment. Compliance of the patient with the prescribed treatment time is monitored. Thecompression system1 is operated for several or more cycles as needed to allow the system to settle into a steady state and to collect steady state data before compliance determination begins. However, a compliance timer or counter can be started prior to onset of compliance determination. Thus, at the start of thecompliance determination method740 thecompression garment10 is in the wrapped configuration and operating under a normal (steady state) operating condition. Thesystem1 operates atstep750 under default conditions where the one ormore processors7 instruct thepressure sensor27 to measure the pressure in the manifold29 throughout the compression cycle. Pressure data is discarded over time and replaced with new more recent pressure data as it becomes available. The one ormore processors7 check at760 for the occurrence of a trigger suggesting that thecompression garment10 may have been unwrapped.
• In general, a trigger may occur when a measured result differs from an expected result, with the expected result based on the most recent adjustment history and steady state control error(s). A trigger may include, for example and without limitation one or more of the following: an end of cycle pressure change from the previous compression cycle(s) for at least one of the bladders13a,13b,13c;an end of inflation pressure change from the previous compression cycle(s) for at least one of the bladders13a,13b,13c;an adjustment of pump21 caused by said pressure (e.g., an error in the target measurement); a curvature coefficients change from the previous inflation phase(s) of at least one of the bladders13a,13b,13c;an inflation phase slope change from the previous compression cycle(s) for at least one of the bladders13a,13b,13c;a change in the measured pressure of one or more of the bladders at the end of a cycle of operation, a change in the slope of measured pressure during the vent phase, a change in the initial offset of measured pressure from zero from the previous compression cycle(s); a pressure in one of the inflatable bladders13b,13chaving a lower target pressure exceeding the pressure in another of the inflatable bladders13a,13bhaving a higher target pressure, a smaller difference in peak pressure between bladders13aand13b,a change in the magnitude of adjustment made to operation of the pump21, a statistically significant change the pressure waveform and any unplanned disturbances in the measured pressures or unplanned adjustments made by the compression system1.
• Referring toFIG. 8, until a trigger occurrence is detected, thecompression system1 continues normal operation (step762). If a trigger occurrence is detected, a determination is made at764 whether the occurrence exceeds a predetermined condition such as, for example, an expected error for steady state operation. Additionally or alternatively, a pressure change/disturbance producing a control system response greater than three times that of an expected change/disturbance could serve as a predetermined condition. An “expected change/disturbance” could be pre-set or could be criteria established by thecontroller5 through operation of the controller in a steady state for a period of time. Additionally or alternatively, an adjustment to pump21 that is greater than a predetermined threshold as compared to a most recent adjustment could serve as a predetermined condition. For example, a trigger may occur when a new adjustment ofpump21 is greater than 100% of the previous adjustment. Thecompression system1 continues762 normal operation if it is determined that the trigger occurrence does not exceed the predetermined threshold or satisfy the criteria.
• Referring toFIGS. 7 and 8, data gathering is begun at770 if it is determined that the trigger occurrence is valid for use in confirming that a change in condition of thecompression garment10 from wrapped to unwrapped has occurred. The one ormore processors7 activate a “sleeve removed” compression cycle counter at772 for counting a number of “sleeve removed” compression cycles for which data is gathered to confirm the trigger occurrence as an indication that thegarment10 has become unwrapped. The number of “sleeve removed” compression cycles are counted at774 until a sufficient amount of data (i.e., pressure signals) is obtained. The number of “sleeve removed” compression cycles needed to obtain a sufficient amount of data to determine whether thegarment10 is in the unwrapped configuration can be different under different circumstances. In one embodiment, the number of “sleeve removed” compression cycles is between about ten to about twenty compression cycles. Generally, a sufficient amount of data is determined to be obtained when the pressure signals again reach a steady state after the initial trigger occurrence. Thememory33 stores the data associated with the “sleeve removed” cycle separately from the reference data obtained during normal operation of thesystem1. Once enough data is obtained at776, the one ormore processors7 retrieve the data obtained during the normal operation of thesystem1 atstep778. The one ormore processors7 analyze the “sleeve removed” data after the pressure signals reach the steady state at780 to determine bladder pressure values for comparing to the data obtained while thecompression system1 was operating in the normal condition.
• The one ormore processors7 determine atstep790 whether thegarment10 is in the wrapped or unwrapped condition by comparing the “sleeve removed” data to the normal operating condition reference data. Thecompression system1 continues normal operation if the one ormore processors7 determine at792 that thegarment10 has not been removed and is still in the wrapped configuration. The one ormore processors7 alter recordation of a monitored parameter if it is determined at794 that thegarment10 has been removed, placing the garment in an unwrapped configuration. Comparing the “sleeve removed” data to the normal operating condition data at step790 can include without limitation one or more of: comparing the end of cycle pressure from the “sleeve removed” data to the end of cycle pressure from the normal operating condition data for at least one of the bladders13a,13b,13c;comparing an end of inflation pressure from the “sleeve removed” data to the end of inflation pressure from the normal operating condition data for at least one of the bladders13a,13b,13c;comparing curvature coefficients from a curve fit on “sleeve removed” data to curvature coefficients from a curve fit on normal operating condition data; comparing an inflation phase slope from the “sleeve removed” data to the inflation phase slope from the normal operating condition data for at least one of the bladders13a,13b,13c;comparing the initial offset of measured pressure from zero on the “sleeve removed” data to the initial offset of measured pressure from zero from the normal operating condition data; comparing a vent phase slope from the “sleeve removed” data to a vent phase slope from the normal operating condition data for at least one of the bladders13a,13b,13c;comparing measured pressures to determine if an inflatable bladder having a lower target pressure has a higher measured pressure than the measured pressure of an inflatable bladder having a higher target pressure; comparing the differences in peak pressures of inflatable bladders13a,13bfrom the “sleeve removed” data to the difference in peak pressures of the bladders13a,13bin the normal operating condition data for a decrease in the difference; comparing the magnitude of adjustments to operation of the pump21 in the “sleeve removed” data to the magnitude of adjustments made in the normal operation data; looking for statistically significant differences in the pressure waveform between the “sleeve removed” data and the normal operation data. For instance, a pressure spike during the vent phase of one of thebladders13a,13b,13cis an indication that thegarment10 is in the wrapped configuration. The comparingstep790 is a confirmatory analysis for confirming the trigger occurrence as an indication that the garment is in the unwrapped configuration.
• If thedata comparisons790 indicate that a statistically significant change in pressure occurred for any one of the data comparisons, and for any one of thebladders13a,13b,13c,the one ormore processors7 indicate that thegarment10 is in the unwrapped configuration and is no longer being used in a compliant manner. Additionally or alternatively, the one ormore processors7 require confirmation from at least two of thebladders13a,13b,13cthat a statistically significant change in pressure occurred for any one of the data comparisons. Additionally or alternatively, the one ormore processors7 require confirmation from all of thebladders13a,13b,13cthat a statistically significant change in pressure occurred for any one of the data comparisons. Additionally or alternatively, the one ormore processors7 require confirmation that a statistically significant change in pressure occurred for at least two of the data comparisons.
• In response to a confirmation of a pressure change, the one ormore processors7 alter recordation of the monitored parameter atstep794 by at least one of halting a compliance meter so that no further compression cycles are indicated as being compliant with a compression therapy regimen (e.g., a compliance timer stops incrementing), providing an alarm indication alerting the wearer or clinician of the noncompliance, halting operation of thecompression system1, and storing the results of the comparison in the memory33 (e.g., a flag).
• Optionally, referring toFIG. 9, themethod740 of determining whether thecompression garment10 is in the wrapped or unwrapped configuration continues by collecting atstep902 additional “sleeve removed” data after the determination is made by the one ormore processors7 that thegarment10 is in the non-compliant, unwrapped configuration. The one ormore processors7 analyze and compare at904 the additional “sleeve removed” data to the normal operating condition data. The one ormore processors7 determine at906 that thegarment10 has returned to the wrapped configuration and is again being used in a compliant manner if the data comparisons at904 indicate that the additional “sleeve removed” data matches or closely matches the normal operating condition data for any one of thebladders13a,13b,13c.In response, the one ormore processors7 alter recordation of the monitored parameter by at least one of resuming operation of thecompression system1, resuming a compliance meter so that subsequent compression cycles are indicated as being compliant, providing a message alerting the wearer or clinician of the compliance, and storing the results of the comparison in thememory33. The one ormore processors7 continue to collect at902 additional “sleeve removed” data until the one ormore processors7 determine that the pressure signals, such as the measures described above, match or closely match the normal operating condition pressure signal if the data comparisons at904 indicate that a statistically significant change in pressure remains for any one of the data comparisons.
• As can be seen fromFIGS. 4 and 5, the pressure measurement produced by thepressure sensor27 is slightly higher than the actual pressure within thebladder13a,13b,13c.For the purposes of using the pressure sensor signal to determine compliance, the difference in pressures is negligible. Alternatively, by briefly deactivating thefluid source21 the pressure measured by thepressure sensor27 normalizes to the actual pressure in the bladder in fluid communication with the manifold29.
• Additionally or alternatively, the linear regression for the inflation phases of thebladders13a,13b,13ccan be further analyzed for comparing between the wrapped and unwrapped conditions. For instance, standard deviation, P-values, max and min values, and an average value can be calculated and compared between the wrapped and unwrapped conditions to further distinguish between the two conditions. Advanced statistics associated with regression analyses (e.g. the curve fitting analysis described herein), such as analysis of residuals, for distinguishing sleeve-on and sleeve-off conditions is also within the scope of the present disclosure.
• While the curve fits for the inflation phase of thebladders13a,13b,13chave been described as best fit lines, the models could be polynomial curve fits. Referring toFIG. 10, pressure signals from the inflation phase ofbladder13aare modeled with a fifth order polynomial curve fit in the wrapped configuration (1002) and the unwrapped configuration (1004). The fifth order polynomial curve fit accurately represents more dynamic curvature of the inflation phases without being overly responsive to the changes in the pressure signals. Other order polynomial curve fits are also envisioned. As an example, lower orders can be used such as when the curvature is less dynamic and higher orders are not required.
• The polynomial curve fits during the inflation phases of thebladders13a,13b,13cin the wrapped configurations are generally straighter (i.e., more linear) than the polynomial curve fits for the inflation phases of thebladders13a,13b,13cin the wrapped configuration. Additionally, for the distal andintermediate bladders13a,13b,the pressures throughout the inflation phase in the unwrapped configuration are higher than the pressures throughout the inflation phase in the wrapped configuration. The reverse condition is true for theproximal bladder13cwhere the pressures throughout most of the inflation phase in the wrapped configuration are higher than the pressures throughout most of the inflation phase in the unwrapped configuration. Additionally, the starting pressures, or offset, for thebladders13aand13b,in the unwrapped configuration are higher than the starting pressures for thebladders13aand13bin the wrapped configuration. By recognizing the occurrence of these differing characteristics thecompression system1 can determine when thegarment10 is in a compliant, wrapped configuration and when thegarment10 is in a non-compliant, unwrapped configuration.
• Additionally or alternatively, the polynomial curve fits for the inflation phases of thebladders13a,13b,13ccan be further analyzed for comparing between the wrapped and unwrapped conditions. For instance, standard deviation, P-values, max and min values, and an average value can be calculated and compared between the wrapped and unwrapped conditions to further distinguish between the two conditions. Advanced statistics associated with regression analyses (e.g. the curve fitting analysis described herein), such as analysis of residuals, for distinguishing sleeve-on and sleeve-off conditions is also within the scope of the present disclosure.
• Referring toFIG. 11, a representative compression cycle pressure profile for a wrapped configuration of thecompression garment10 is illustrated. This graph illustrates signals from thepressure sensor27. A single compression cycle for all three of thebladders13a,13b,13cin a wrapped configuration of thecompression garment10 includes acompression period1102 and adecompression period1104. Referring toFIG. 12, a representative compression cycle pressure profile for an unwrapped configuration of thecompression garment10 is illustrated. Acompression period1202 and adecompression period1204 illustrate a single compression cycle for all three of thebladders13a,13b,13cfor the unwrapped configuration of thecompression garment10. The computer executable instructions embodied on the computerreadable storage medium33 include instructions to cause the one ormore processors7 to monitor the signals from thepressure sensor27 that are indicative of the bladder pressures during thedecompression periods1104,1204. The computer executable instructions cause the one ormore processors7 to detect a difference between the pressure signal ofdecompression period1104 and the pressure signal ofdecompression period1204. For example, the pressure signal during thedecompression period1104 includes pressure impulses, indicated generally at1106 inFIG. 11, which thecontroller5 interprets as indicative of wearer movement when thecompression garment10 is in a wrapped configuration. The pressure signal during thedecompression period1204 is relatively static (i.e., no impulses are present) which thecontroller5 interprets as indicative of thecompression garment10 being in an unwrapped configuration. By analyzing the pressure signals of thedecompression periods1104,1204, the computer executable instructions cause the one ormore processors7 to determine whether or not thecompression garment10 is in a wrapped configuration or unwrapped configuration based on the presence (i.e., occurrence) or absence (i.e., non-occurrence) of one ormore pressure impulses1106 during thedecompression periods1104,1204.
• Referring again toFIG. 11, in another embodiment of thecompression system1, bladder pressures of thebladders13a,13b,13care locked and the computer executable instructions cause the one ormore processors7 to detect a rise (e.g., increase) in the pressure signal during thedecompression period1104 when thecompression garment10 is in a wrapped configuration substantially around a limb of a wearer. The pressure signal during the decompression period1204 (FIG. 12) is relatively static (i.e., no pressure rise is present) which thecontroller5 interprets as indicative of thecompression garment10 being in an unwrapped configuration. The computer executable instructions cause the one ormore processors7 to determine whether thecompression garment10 is in a wrapped or unwrapped configuration based on the presence (i.e., occurrence) or absence (i.e., non-occurrence) of a pressure rise during thedecompression periods1104,1204.
• Referring toFIG. 13, the computer executable instructions embodied on the computerreadable storage medium33 cause the one ormore processors7 to execute amethod1300 of determining whether the compression garment is in the wrapped or unwrapped configuration by detecting one or more pressure impulses in the pressure signal received from thepressure sensor27. Thecompression system1 operates atstep1302 to inflate and deflatebladders13a,13b,13cto apply compression treatment to a wearer's limb, and to vent thebladders13a,13b,13cdown to a target value, such as1-2 mmHg. The computer executable instructions cause the one ormore processors7 to determine atstep1304 whether the pressure in thebladders13a,13b,13chas reached the target value. If the target value has not been reached, the computer executable instructions cause the one ormore processors7 to continue venting thebladders13a,13b,13cand the process returns back tostep1304. If the target value has been reached, the computer executable instructions cause the one ormore processors7 to stop venting thebladders13a,13b,13cand monitor the pressure signal frompressure sensor27 for impulses during the decompression period atstep1306. It is appreciated that a filtered signal may be assumed such that any impulse observed would be above baseline signal noise without departing from the scope of the present disclosure. The signal may be filtered, for example, by filtering circuitry incontroller5 and/or by digital filtering techniques implemented by the one ormore processors7 via the computer executable instructions. It is appreciated that the computer executable instructions may cause the one ormore processors7 to perform waveform peak detection to determine the amplitude of anomalous peaks versus peaks within the expected noise without departing from the scope of the present disclosure. It is also appreciated that the computer executable instructions may cause the one ormore processors7 to utilize signal threshold limit detection without departing from the scope of the present disclosure. For example, if an impulse greater than1 mmHg above noise is detected, then that impulse is considered a pressure impulse. The computer executable instructions cause the one ormore processors7 to implement a counter, with which a count is kept for the number of consecutive cycles in which no impulses are observed.
• Atstep1308, the computer executable instructions cause the one ormore processors7 to determine whether an impulse was detected by theprocessor7 atstep1306. If an impulse was detected duringstep1306, the computer executable instructions cause the one ormore processors7 to reset1310 the counter to zero because the impulse is indicative of thecompression garment10 being in a wrapped configuration substantially around a limb of a wearer. If an impulse was not detected duringstep1306, then such a nonoccurrence (i.e., absence) of an impulse is indicative of thecompression garment10 being in an unwrapped configuration away from a limb of a wearer. In such a case, the computer executable instructions cause the one ormore processors7 to determine whether the count of the counter has met or exceeded a counter threshold atstep1312. For example, the threshold may be ten consecutive cycles, but one skilled in the art will appreciate that the threshold may be any integer value. Meeting or exceeding the threshold indicates that thecompression garment10 is in the unwrapped configuration away from the limb of the wearer because a pressure anomaly (e.g., pressure impulse) would have been detected by the one ormore processors7 if thecompression garment10 were in the wrapped configuration.
• If the one ormore processors7 determine atstep1312 that the count of the counter has met or exceeded a counter threshold, then the computer executable instructions cause the one or more processors to take a required action atstep1314. For example, the one ormore processors7 may halt operation, stop a compliance timer, alert a user (e.g., the wearer or caregiver), and the like. If the one ormore processors7 determine atstep1312 that the count of the counter has not reached the counter threshold, then the computer executable instructions cause the one ormore processors7 to increment the count of the counter and fully vent thebladders13a,13b,13catstep1316 and the process returns to step1302.
• In an alternative embodiment, themethod1300 ofFIG. 6 is implemented during Venous Refill Measurements. In such an embodiment,bladder13bis vented to a higher pressure (e.g., 5-7 mmHg) and therefore is more firmly in contact with the limb of the wearer. In this embodiment, pressure impulses due to patient movement are even more evident in the pressure signal ofpressure sensor27.
• Referring toFIG. 14, the computer executable instructions embodied on the computerreadable storage medium33 cause the one ormore processors7 to execute amethod1400 of determining whether the compression garment is in the wrapped or unwrapped configuration by detecting a rise (e.g., increase) in the pressure signal received from thepressure sensor27. Thecompression system1 operates atstep1402 to inflate and deflatebladders13a,13b,13cto apply compression treatment to a wearer's limb, and to vent thebladders13a,13b,13cdown to a target value, such as 1-2 mmHg. The computer executable instructions cause the one ormore processors7 to determine atstep1404 whether the pressure in thebladders13a,13b,13chas reached the target value. If the target value has not been reached, the computer executable instructions cause the one ormore processors7 to continue venting thebladders13a,13b,13cand the process returns to step1404. If the target value has been reached, the computer executable instructions cause the one ormore processors7 to stop venting thebladders13a,13b,13cand monitor the pressure signal frompressure sensor27 for a rise during the decompression period atstep1406. In an embodiment, a filtered signal is assumed such that any rise observed would be above baseline signal noise. The signal may be filtered for example, by filtering circuitry incontroller5 and/or by digital filtering techniques implemented by the one ormore processors7 via the computer executable instructions. The one ormore processors7 monitor the pressure signal for a pressure rise greater than a threshold value (e.g., 1-2 mmHg), which indicates that thecompression garment10 is in a wrapped configuration substantially around a limb of a wearer. A lack of a rise in the pressure signal, or a rise less than the threshold value, indicates that thecompression garment10 is in an unwrapped configuration away from a limb of a wearer. The computer executable instructions cause the one ormore processors7 to implement a counter, with which a count is kept for each cycle failing to achieve the threshold pressure rise.
• Atstep1408, the computer executable instructions cause the one ormore processors7 to determine whether a pressure rise greater than the threshold value was detected by theprocessor7 atstep1406. If a pressure rise greater than the threshold was detected duringstep1406, the computer executable instructions cause the one ormore processors7 to reset1410 the counter to zero because the pressure rise is indicative of thecompression garment10 being in a wrapped configuration substantially around a limb of a wearer. If a rise above the threshold was not detected duringstep1406, then such a nonoccurrence of a pressure rise is indicative of thecompression garment10 being in an unwrapped configuration away from a limb of a wearer. In such a case, the computer executable instructions cause the one ormore processors7 to determine whether the count of the counter has met or exceeded a counter threshold atstep1412. For example, the threshold may be ten consecutive cycles, but one skilled in the art will appreciate that the threshold may be any integer value. Meeting or exceeding the threshold indicates that thecompression garment10 is in the unwrapped configuration away from the limb of the wearer because a pressure anomaly (e.g., pressure rise) would have been detected by the one ormore processors7 if thecompression garment10 were in the wrapped configuration.
• If the one ormore processors7 determine atstep1412 that the count of the counter has met or exceeded a counter threshold, then the computer executable instructions cause the one or more processors to take a required action atstep1414. For example, the one ormore processors7 may halt operation, stop a compliance timer, alert a user (e.g., the wearer or caregiver), and the like. If the one ormore processors7 determine atstep1412 that the count of the counter has not reached the counter threshold, then the computer executable instructions cause the one ormore processors7 to increment the count of the counter and fully vent thebladders13a,13b,13catstep1416 and the process returns to step1402.
• In alternative embodiment, the actual shape of the pressure profile of the signal generated bypressure sensor27 is in itself a potential indicator. For example, the shape of the profile could be calculated such that when the resulting function (i.e., the shape) matches a pre-determined function (i.e., shape), the computer executable instructions cause the one ormore processors7 to determine that thecompression garment10 is in the wrapped configuration. Conversely, failure of the resulting function to match the pre-determined function would result in the computer executable instructions causing the one ormore processors7 to determine that thecompression garment10 is in the unwrapped configuration. Such an embodiment may be used with the counters described in conjunction withmethods1300,1400 described above.
• Referring toFIG. 15A, a pressure signal from thepressure sensor27 is shown for one of thebladders13a,13b,13cin a wrapped configuration of thecompression garment10 on a limb of the wearer during a representativebladder inflation period1502 and apressure hold period1504. In the example inFIG. 15A, thepressure hold period1504 is about twenty-seven seconds in duration and represents thebladder13a,13b,13cinflated to about 45 mmHg, which is a typical inflation threshold of a therapeutic cycle of thebladders13a,13b,13c.In accordance with another embodiment of the disclosure, thepressure hold period1504 may be about twenty seconds in duration and represent one of thebladders13a,13b,or13cinflated to about 200 mmHg. Accordingly, the oscillation amplitude in the pressure signal for a bladder inflated to about 200 mmHg will be higher than the oscillation amplitudes illustrated herein associated for a bladder inflated to about 45 mmHg.
• Referring toFIG. 15B, awaveform1504′ shows the result of a band-pass filtering technique applied to a subset signal of interest of thepressure hold period1504 such that a frequency range (e.g., 0.5 Hz to 25 Hz, 0.5 Hz to 5 Hz, etc.) has been extracted. The representative subset portion of thepressure hold period1504 is shown on a smaller scale, as compared toFIG. 15A, such that pulses are visible in the pressure signal during thepressure hold period1504′. The pulses in the pressure pulse inFIG. 15B are associated with a pressure effect produced on thebladder13a,13b,or13cby the pulse of the wearer. Waveform pulsations associated with the pulse of the wearer of thecompression garment10 remain evident inwaveform1504′. The computer executable instructions embodied on the non-transitory, computerreadable storage medium33 include instructions to cause the one ormore processors7 to receive a signal from thepressure sensor27, the received signal being indicative of the fluid pressure in one or more of thebladders13a,13b,13cduring thebladder inflation period1502 and thepressure hold period1504.
• In certain embodiments, the computer executable instructions further include instructions to cause the one ormore processors7 to refine further the signal from thepressure sensor27 to extract, during thepressure hold period1504, only frequencies associated with the typical cardiac cycle range of a human. For example, the computer executable instructions can include computer executable instructions to cause the one ormore processors7 to extract (e.g., through a band-pass filtering technique) frequencies in the range of 0.5 Hz to 25 Hz.
• FIG. 15B shows that, as the oscillation amplitude decreases, the impact of noise on the signal is more significant (i.e., the signal-to-noise ratio is smaller). Additional pre-processing and/or post-processing of the data can be useful to obtain less distorted results. In some embodiments, the computer executable instructions further include instructions to cause the one ormore processors7 to filter the signal of thepressure hold period1504 to remove frequencies that are not associated with a pulse of a human wearer and to cause the one ormore processors7 to implement one or more peak detection algorithms and/or compliance monitoring algorithms. In certain embodiments, the one or more computer executable instructions further include instructions to cause the one ormore processors7 to perform the additional pre-processing and/or post-processing to decrease the impact of noise on the signal received from thepressure sensor27. It should be appreciated that the signal received from thepressure sensor27 and processed by the one ormore processors7 includes pulsation associated with the heartbeat of the wearer and not the actual heart rate of the wearer. For example, the blood flow as the wearer's heart beats creates pressure on at least one ofinflatable bladders13a,13b,13c,which thepressure sensor27 detects and generates pressure signals representative thereof.
• Referring toFIG. 15C, thewaveform1504′ is overlaid on awaveform1504″, thewaveform1504″ being the result of a smoothing algorithm filtering technique applied towaveform1504′ by the one ormore processors7. In this exemplary embodiment inFIG. 15C, the smoothing follows a rectangular window at five times (e.g., 5×) the moving range. Even at pressures as low as those associated with typical Venous Refill Detection (VRD) techniques (e.g., about 5 to about 20 mmHg), the waveform still provides evidence of pulsations indicative of sufficient contact between the wearer and thecompression garment10.
• FIG. 16 shows a pressure signal received from thepressure sensor27 during a representative bladderpressure hold period1602 pressure profile of one of thebladders13a,13b,13cfor an unwrapped configuration of thecompression garment10. The overall amplitude of thepressure profile1602 is less than the amplitudes of the analogous pressure hold period1504 (shown inFIG. 15A). The absence of clear, repeating pulses in thepressure profile1602 is an indication that thecompression garment10 is in an unwrapped configuration or is not properly worn by the wearer.
• FIG. 17A shows a pressure signal received from thepressure signal27 and representative bladder pressure profile for one ofbladders13a,13b,13c.The pressure profile includes atherapy cycle period1702, abladder vent period1704, a bladdertest inflation period1706, and a bladderpressure hold period1708. At the end of thetherapy cycle1702, the tested bladder (e.g., one ofbladders13a,13b,13c) vents during thebladder vent period1704. After thebladder vent period1704, a short inflation is applied to the tested bladder during thebladder inflation period1706 until the tested bladder achieves a pressure of about 30 mmHg. The one ormore processors7 execute computer executable instructions such that pulse detection, as further described below, is performed by the one ormore processors7 during the bladderpressure hold period1708, which is about ten seconds in this exemplary embodiment. The bladderpressure hold period1708 can be for a longer or shorter duration, provided that the duration is long enough to ensure that multiple pulses occur within the duration.
• FIG. 17B illustrates awaveform1708′ indicative of the result of a filtering technique applied to a signal of interest during thepressure hold period1708. In some embodiments, the computer-executable instructions include instructions to cause the one ormore processors7 to detect dominant peaks and check that the waveform falls within an expected range (e.g., 60-100 beats per minute (bpm) for a human wearer). In some embodiments, the expected range is 60-100 beats per minute (bpm) for a human wearer. It should be appreciated, however, that a wider range (e.g., 30-120 bpm) can be used to account for wearers who may be of ill-health and/or to account for measurements that may occur at locations on the body far away from the heart (e.g., the lower leg). In this exemplary embodiment, the one ormore processors7 detect pulsation associated with the heartbeat of the wearer and not the actual heart rate of the wearer.
• FIG. 18 is a schematic representation of an exemplary method1800 of analyzing waveform data received from thepressure sensor27 to determine whether thecompression garment10 is in the wrapped or unwrapped configuration around a limb of a wearer of the garment by detecting pulsations associated with the heartbeat of the wearer. This exemplary method can be carried out by the one ormore processors7 through execution of computer executable instructions embodied on the non-transitory, computerreadable storage medium33.
• The one ormore processors7 execute computer executable instructions to sample1802 initial pressure. In some embodiments, the initial pressure sampling is done at a rate of 100 Hz or higher and typical signal conditioning is used to remove baseline noise. Additionally or alternatively, thesampling1802 may be expanded to include attenuation of frequencies just under a low cutoff (e.g., 0.25 Hz).
• Apost-process waveform analysis1804 further includes abandpass filter1806, anadditional filtering1808, and apeak detection1810. During thebandpass filter1806, the signal of interest is filtered using a bandpass filtering technique in a typical range of frequencies associated with a typical heartrate range of a human wearer (e.g., 0.5-4 Hz for a human wearer).
• During theadditional filtering1808, the peaks of the bandpass filtered signal are further refined. The additional filtering can include a lowpass filter with a cutoff of 5 Hz to produce a filtered value. Additionally or alternatively, the additional filtering can include a smoothing algorithm using the five most recent samples of the moving range to produce a filtered value. It should be appreciated that more than one filtering technique may be applied to the bandpass filtered signal during theadditional filtering step1808.
• During apeak detection1810, a peak detection is performed to check that the peaks of the filtered signal correspond to a heartbeat range of a typical human wearer. Thepeak detection1810 can be based on a predetermined threshold (e.g., look only at peaks with a magnitude greater than 0.05 mmHg). Additionally or alternatively, thepeak detection1810 can be based on examining for repeating signals with frequencies within a heartbeat range of a typical human wearer, independent of magnitude (e.g., expanded to 30-240 bpm for margin). For example, a frequency analysis computation may be performed to check that a repeating signal with frequency within the heartbeat range of a typical human wearer is detected. Additionally or alternatively, thepeak detection1810 can be based on the highest magnitude peaks and checking that the frequency of those peaks falls within the expected heartbeat range of a typical human wearer. It should be appreciated that more than one peak detection technique may be used during thepeak detection1810. In some embodiments,peak detection1810 includes a combination of peak detection based on a predetermined threshold and based on the highest magnitude peaks and checking that the frequency of those peaks falls within the expected heartbeat range of a typical human wearer because the signal-to-noise ratio is high enough that the pulses are plainly evident.
• The computer executable instructions cause the one ormore processors7 to determine1812 whether a features of a pulse of the wearer were detected during thepeak detection1810. If features of a pulse are determined1812 to be present, the results of a positive determination can be indicated1816. For example, theindication1816 can include sending a visual representation to a display device associated with thecompression system1. Additionally or alternatively, theindication1816 can include incrementing and/or pausing a timer. Upon theindication1816, the process ends atstep1818 and returns back tostep1802. If an impulse is not detected atstep1812, the computer executable instructions cause the one ormore processors7 to return a null value atstep1814. Afterstep1814, the process ends atstep1818 and returns tosampling1802.
• Referring toFIG. 19, is a schematic representation of anexemplary method1900 of analyzing waveform data received from a pressure sensor (e.g., the pressure sensor27) to determine whether a compression garment (e.g., compression garment10) is in the wrapped or unwrapped configuration during a garment verification process. For ease of explanation and for the sake of clarity, themethod1900 is described for a single bladder (e.g., one of thebladders13a,13b,or13c). It should be appreciated, however, that themethod1900 can be repeated to check for additional bladders corresponding to different valves.
• Themethod1900 begins atstep1902 and the desired bladder valve (e.g.,bladder valve25a,25b,25c) is opened1904. A pressurized fluid source (e.g., pressurized fluid source21) is turned on1906 until pressure in the corresponding bladder exceeds about 120 mmHg.
• A pressure signal is received1908 from thepressure sensor27 for a period of time. Adetermination1910 is made regarding whether all data are available. If all data are not available, pressure signals continue to be acquired1912 and the pressure signal is received1908. If thedetermination1910 is made that all data are available atstep1910, close the corresponding valve is closed1914 and a pulse detection algorithm is performed.
• In some embodiments, the pulse detection algorithm includes one or more steps of thepost-process waveform analysis1804 described above.
• Adetermination1916 is made regarding whether a pulse is detected after the valve is closed1914 and fluid is isolated in the bladder. The lack of detection of a pulse is indicative of thecompression garment10 being in an unwrapped configuration away from a limb of the wearer atstep1918 and the method proceeds to step1932, where a compliance time is not incremented, before ending the method atstep1936. The detection of a pulse atstep1916 is indicative of thecompression garment10 being in a wrapped configuration around a limb of the wearer atstep1920 and the method continues to step1930.
• Atstep1922, the computer executable instructions cause the one ormore processors7 to read the pressure after one second has elapsed after the pump is turned on instep1906. Atstep1924, the computer executable instructions cause the one ormore processors7 to determine whether the pressure is greater than 2.0 mmHg. The pressure exceeding 2.0 mmHg atstep1924 is indicative of thecompression garment10 being present (e.g., in fluid communication withvalve25a,25b,25c) atstep1926 and the method proceeds to step1930. The pressure not exceeding 2.0 mmHg atstep1924 is indicative of thecompression garment10 not being present (e.g., not in fluid communication withvalve25a,25b,25c) atstep1928 and the method proceeds to step1932, where a compliance time is not incremented, before ending the method atstep1936.
• Atstep1930, the computer executable instructions cause the one ormore processors7 to determine whether thecompression garment10 is present and in a wrapped configuration around a limb of the wearer. If either thecompression garment10 is determined to not be present or not be in a wrapped configuration around a limb of the wearer, then the method proceeds to step1932 where a compliance time is not incremented before ending the method atstep1936. If thecompression garment10 is determined by the one ormore processors7 to be present and be in a wrapped configuration, then the method proceeds to step1934 where a compliance time is incremented before ending the method atstep1936.
• Referring toFIG. 20, the computer executable instructions embodied on the computerreadable storage medium33 cause the one ormore processors7 to execute amethod2000 of analyzing waveform data received from thepressure sensor27 to determine whether the compression garment is in the wrapped or unwrapped configuration following the end of a cycle pressure. Themethod2000 begins atstep2002 and proceeds to step2004, where the computer executable instructions cause the one ormore processors7 to complete a prophylactic compression cycle. Atstep2006, the computer executable instructions cause the one ormore processors7 to vent the bladders corresponding to the ankle and thigh of the wearer (e.g.,bladders13aand13c). Atstep2008, the computer executable instructions cause the one ormore processors7 to hold the pressure in the bladder corresponding to the calf of the wearer (e.g.,bladder13b) for a predetermined period of time (e.g., 10 seconds) and acquire pressure signals via thepressure sensor27.
• Atstep2010, the computer executable instructions cause the one ormore processors7 to determine whether all of the data is available. If all of the data is not available atstep2010, then the method proceeds to step2012 to continue acquiring pressure signals from thepressure sensor27 before continuing back tostep2008. If all of the data is available atstep2010, then the method proceeds to step2014 where the computer executable instructions cause the one ormore processors7 to perform the pulse detection algorithm. In some embodiments, the pulse detection algorithm includes one or more steps of thepost-process waveform analysis1804 described above. Atstep2016, the computer executable instructions cause the one ormore processors7 to determine whether a pulse is detected atstep2014. The lack of detection of a pulse is indicative of thecompression garment10 being in an unwrapped configuration away from a limb of the wearer atstep2022. The method then proceeds to step2024, where the computer executable instructions cause the one ormore processors7 to not increment a compliance time and cause the one ormore processors7 to take one or more actions (e.g., alert the user) before ending the method atstep2026. The detection of a pulse atstep2016 is indicative of thecompression garment10 being in a wrapped configuration around a limb of the wearer atstep2018. The method then proceeds to step2020, where the computer executable instructions cause the one ormore processors7 to increment a compliance time before ending the method atstep2026.
• Referring toFIG. 21, the computer executable instructions embodied on the computerreadable storage medium33 cause the one ormore processors7 to execute amethod2100 of analyzing waveform data received from thepressure sensor27 to determine whether the compression garment is in the wrapped or unwrapped configuration during a Venous Refill Determination (VRD). Themethod2100 begins atstep2102 and proceeds to step2104, where the computer executable instructions cause the one ormore processors7 to complete a prophylactic compression cycle. Atstep2106, the computer executable instructions cause the one ormore processors7 to vent the bladders corresponding to the ankle and thigh and of the wearer (e.g.,bladders13aand13c). Atstep2108, the computer executable instructions cause the one ormore processors7 to vent the pressure in the bladder corresponding to the calf of the wearer (e.g.,bladder13b) to a VRD target. Atstep2110, the computer executable instructions cause the one ormore processors7 to perform VRD as scheduled. Once the VRD measurement is initiated, the computer executable instructions cause the one ormore processors7 to start a secondary process to acquire pressure data from thepressure sensor27 for parallel pulse detection. Atstep2114, the computer executable instructions cause the one ormore processors7 to acquire pressure signals from thepressure sensor27 while VRD is in progress.
• Atstep2116, the computer executable instructions cause the one ormore processors7 to determine whether all of the data is available. If all of the data is not available atstep2116, then the method proceeds to step2118 to continue acquiring pressure signals from thepressure sensor27 before continuing back tostep2114. If all of the data is available atstep2116, then the method proceeds to step2120 where the computer executable instructions cause the one ormore processors7 to perform the pulse detection algorithm. In some embodiments, the pulse detection algorithm includes one or more steps of thepost-process waveform analysis1804 described above. Atstep2122, the computer executable instructions cause the one ormore processors7 to determine whether a pulse is detected atstep2120. The lack of detection of a pulse is indicative of thecompression garment10 being in an unwrapped configuration away from a limb of the wearer atstep2128. The method then proceeds to step2130, where the computer executable instructions cause the one ormore processors7 to not increment a compliance time and cause the one ormore processors7 to take one or more actions (e.g., alert the user) before ending the method atstep2132. The detection of a pulse atstep2122 is indicative of thecompression garment10 being in a wrapped configuration around a limb of the wearer atstep2124. The method then proceeds to step2126, where the computer executable instructions cause the one ormore processors7 to increment a compliance time before ending the method atstep2132.
• Referring toFIG. 22, the computer executable instructions embodied on the computerreadable storage medium33 cause the one ormore processors7 to execute a method2200 of analyzing waveform data received from thepressure sensor27 to determine whether the compression garment is in the wrapped or unwrapped configuration as an independent cycle. The method2200 begins atstep2202 and proceeds to step2204, where the computer executable instructions cause the one ormore processors7 to complete a prophylactic compression cycle. Atstep2206, the computer executable instructions cause the one ormore processors7 to vent allbladders13a,13b,13c.Atstep2208, the computer executable instructions cause the one ormore processors7 to open a desired valve (e.g.,valve25b) and inflate a desired bladder (e.g.,bladder13b) to a desired pressure (e.g., 10-120 mmHg). Atstep2210, the computer executable instructions cause the one ormore processors7 to acquire pressure signals via thepressure sensor27 for a predetermined period of time (e.g., 10 seconds).
• Atstep2212, the computer executable instructions cause the one ormore processors7 to determine whether all of the data is available. If all of the data is not available atstep2212, then the method proceeds to step2214 to continue acquiring pressure signals from thepressure sensor27 before continuing back tostep2210. If all of the data is available atstep2212, then the method proceeds to step2216 where the computer executable instructions cause the one ormore processors7 to close the corresponding valve (e.g.,25b) and perform the pulse detection algorithm. In some embodiments, the pulse detection algorithm includes one or more steps of the post-process waveform analysis804 described above. Atstep2218, the computer executable instructions cause the one ormore processors7 to determine whether a pulse is detected atstep2216. The lack of detection of a pulse is indicative of thecompression garment10 being in an unwrapped configuration away from a limb of the wearer atstep2224. The method then proceeds to step2226, where the computer executable instructions cause the one ormore processors7 to not increment a compliance time and cause the one ormore processors7 to take one or more actions (e.g., alert the user) before ending the method atstep2228. The detection of a pulse atstep2218 is indicative of thecompression garment10 being in a wrapped configuration around a limb of the wearer atstep2220. The method then proceeds to step2222, where the computer executable instructions cause the one ormore processors7 to increment a compliance time before ending the method atstep2228.
• FIGS. 23A-C are a schematic representation of anexemplary method2300 of analyzing waveform data received from thepressure sensor27 to determine whether thecompression garment10 is in the wrapped or unwrapped configuration around a limb of a wearer of the garment by detecting pulsations associated with the heartbeat of the wearer. This exemplary method can be carried out by the one ormore processors7 through execution of computer executable instructions embodied on the non-transitory, computerreadable storage medium33.
• Themethod2300 begins and proceeds to step2302, where the computer executable instructions cause the one ormore processors7 to complete a prophylactic compression cycle. Atstep2304, the computer executable instructions cause the one ormore processors7 to vent the bladders corresponding to, for instance, the ankle and thigh of the wearer (e.g.,bladders13aand13c) and to vent the bladder corresponding to, for instance, the calf of the wearer (e.g.,bladder13b) until a target pressure is achieved. In an embodiment, the target pressure comprises an initial lower target pressure of about 5 to about 7 mmHg. Alternatively, the target pressure comprises about 26 to about 32 mmHg when the initial lower target pressure does not produce the expected result. The initial lower target pressure provides an exemplary benefit of exerting less pressure against the limb of the wearer, which is more comfortable for the patient relative to higher pressures, before re-trying at the higher target pressure, which is less comfortable for the patient.
• Upon reaching the target pressure, the computer executable instructions cause the one ormore processors7 to retain the pressure in the bladder corresponding to the calf of the wearer (e.g.,bladder13b) while the signal is acquired at a rate of about 100 Hz for a period of at least about 15 seconds. In an embodiment, the period comprisespressure hold period1504, as further described herein. A hold period of longer than about 15 seconds may also be utilized without departing from the scope of the invention. Atstep2308, the computer executable instructions cause the one ormore processors7 to vent the pressure in the bladder corresponding to the calf of the wearer (e.g.,bladder13b).
• Following the venting of the measurement bladder (e.g.,bladder13b), the computer executable instructions cause the one ormore processors7 to perform further signal conditioning which prepares the data for the patient detection algorithm. As shown inFIG. 23A, the computer executable instructions cause the one ormore processors7 to band-pass filter2310 the waveform data. In an embodiment, the most recent1024 acquired samples, which correspond to a time window of about 10 seconds, are passed through band-pass filter2310 having a pass-band of about 0.5-25 Hz to isolate the signals reflective of a cardiac cycle of the wearer. In an embodiment, the first three samples of the1024 acquired samples are disregarded as a settle time period. It will be understood by one of ordinary skill in the art that other amounts of most recent acquired samples may be utilized without departing from the scope of the invention. For example, any number of most recent acquired samples being a power of two aids in frequency calculation.
• The computer executable instructions cause the one ormore processors7 to pass the output of the band-pass filter2310 through a low-pass filter2312 having a low pass cutoff frequency of about 5 Hz. In an embodiment, low-pass filter2312 further removes noise in the waveform data and reveals pulsations associated with the circulatory system of the lower limb of the wearer. Referring toFIG. 24, an exemplary signal from the output of low-pass filter2312 is shown. In this embodiment, the signal includes about1024 samples having crisp pulsations associated with the circulatory system of the lower limb of the wearer.
• With the filtered waveform data available, the computer executable instructions cause the one ormore processor7 to perform several subsequent calculations on the filtered waveform data to determine whether thecompression garment10 is in the wrapped or unwrapped configuration around a limb of a wearer of the garment. In an embodiment, the subsequent calculations are referred to as post-processing of the filtered waveform.
• Referring again toFIG. 23A, the computer executable instructions cause the one ormore processors7 to perform post-processing of the filtered waveform at2314,2316, and2318. As shown, one ormore processors7 calculate the standard deviation of the filtered waveform data and/or portions thereof. It is empirically known that a compression garment in an unwrapped configuration (i.e., idle) has a stable, flat pressure signal including only normal white noise. In contrast, a pressure signal representative of a pressure in a compression garment in a wrapped configuration around a limb of a wearer of the garment includes pulsations and/or other measureable signal characteristics. Therefore, it is possible to distinguish a compression garment in a wrapped configuration around a limb of a wearer from a compression garment in an unwrapped configuration based, in whole or in part, on this calculation.
• In an embodiment, the computer executable instructions cause the one ormore processors7 to divide the low-pass filtered signal (e.g.,1024 samples) into five sample groups and calculate the standard deviation2314 (σ) for each group. It will be understood by one of ordinary skill in the art that the low-pass filtered signal may be divided into a different number of samples groups, such as when a different number of samples are used for example. An exemplary purpose of dividing the low-pass filtered signal into sample groups is to isolate portions of time. For example, it is known that large anomalous pressure spikes (e.g., due to wearer sneezing, coughing, and the like) in a representative pressure signal occur during normal treatment due to movement of the limb of the wearer and/or other factors. Time-slicing of the signal (e.g., dividing the signal into sample groups) allows the one ormore processors7 to determine if the entire waveform is “steady” or if there is an anomaly within a particular range of the sample. In an embodiment, the computer executable instructions cause the one ormore processors7 to calculate the total standard deviation2314 (σ) for the entire low-pass filtered signal (e.g., 1024 samples).
• After calculating the standard deviation, the computer executable instructions cause the one ormore processors7 to perform peak detection2316. In an embodiment, the one ormore processors7 process the filtered waveform (e.g., 1024 samples) using a windowing technique comprising 32 samples per window. The one ormore processors7 index the peak from each 32-sample window one after the other to produce a down-sampled waveform comprising only the signal peaks (e.g., the signal of interest). For example, the one ormore processors7 may initially index each peak from 1 to 32 and then increment the index by one (e.g. from 2 to 33) as additional waveform signal data is generated. The one ormore processors7 ignore negative peaks. In an embodiment, the 32-sample window leaves a local maximum for each window. Additionally and/or alternatively, the 32-sample window reduces the number of samples by one-quarter, removes negative peaks, and provides awareness that the down-sampled signal is representative of about 10 seconds of real time. Referring toFIG. 25, an exemplary signal from the output of peak detection2316 is shown, including only the true peaks which ultimately reveal the pulsation of interest. In this embodiment, the signal includes about 250 to 300 samples which still correspond to about 10 seconds of real time. In an embodiment, the number of samples will vary depending on the number of peaks identified by the one ormore processors7. In the embodiment illustrated inFIG. 25, the sampling frequency is calculated as the result of the number of samples divided by the amount of time (e.g., Sampling f=N samples/10.24 seconds).
• Referring further toFIG. 23A, with the down-sampled peak detection waveform available, the one ormore processors7 utilize the fundamental frequency to assist in confirming if thecompression garment10 is in the wrapped configuration around a limb of a wearer of the garment by performing a time tofrequency conversion2318. In an embodiment, the computer executable instructions cause the one ormore processors7 to compute a Fourier Transform (e.g., Fast Fourier Transform) of the signal and output the highest magnitude between 0.5 Hz (e.g., about 30 bpm) and 4 Hz (e.g., about 200 bpm). One having ordinary skill in the art will understand that transforms other than a Fast Fourier Transform may be used to discover a cardiac cycle of the wearer without departing from the scope of the invention.
• After completing the post-processing, the computer executable instructions cause the one ormore processors7 to determine whether thecompression garment10 is in an unwrapped configuration or a wrapped configuration around a limb of a wearer of the garment. Referring toFIG. 23B, the computer executable instructions cause the one ormore processors7 to determine, atstep2320, whether the total standard deviation2314 (σ) for the entire low-pass filtered signal (e.g., 1024 samples) is less than or equal to an unwrapped threshold (e.g., 0.25). When the one ormore processors7 determine the total standard deviation is not less than or equal to the unwrapped threshold, themethod2300 continues to step2336 as further described herein. When the one ormore processors7 determine the total standard deviation is less than or equal to the unwrapped threshold, themethod2300 continues to step2322.
• Atstep2322, the computer executable instructions cause the one ormore processors7 to determine whether a predetermined number of segments (e.g. sample groups) into which the low-pass filtered signal has been divided are each less than or equal to the unwrapped threshold (e.g., 0.25). In an alternative embodiment, the one ormore processors7 divide the low-pass filtered signal into five sample groups and determine at2322 whether the standard deviation of each of the five sample groups is less than or equal to the unwrapped threshold. Alternatively, the one ormore processors7 divide the low-pass filtered signal into five sample groups and determine at2322 whether the standard deviation of at least three of the five sample groups is less than or equal to the unwrapped threshold. When the one ormore processors7 determine each of the predetermined number of segments is not less than or equal to the unwrapped threshold, themethod2300 continues back to step2302 to re-try the cycle. When the one ormore processors7 determine each of the predetermined number of segments is less than or equal to the unwrapped threshold, the process continues to step2324.
• At step2324, the computer executable instructions cause the one ormore processors7 to determine whether the largest (e.g., highest amplitude) magnitude in the 0.5-4.0 Hz range of the time to frequency transformed (e.g., Fast Fourier Transform) signal is less than or equal to a threshold X (e.g., 0.2). When the one ormore processors7 determine the largest magnitude in the 0.5-4.0 Hz range is not less than or equal to the threshold X, themethod2300 ends. When theprocessors7 determine at2324 the largest magnitude in the 0.5-4.0 Hz range is less than or equal to the threshold X, the one ormore processors7 determine at2326 that thecompression garment10 is in an unwrapped configuration. In an embodiment, the computer executable instructions cause the one ormore processors7 to declare thecompression garment10 is in an unwrapped configuration (e.g., the wearer is not wearing the compression garment) when the Boolean result ofstep2320 is logical true AND the result ofstep2322 is logical true AND the result of step2324 is logical true.
• Atstep2328, the computer executable instructions cause the one ormore processors7 to determine whether the unwrapped configuration detection at2326 is the second consecutive such determination. When the one ormore processors7 determine the unwrapped configuration detection2326 is not the second consecutive detection, themethod2300 continues back to step2302 to perform a second measurement on the next cycle for the corresponding limb of the wearer. When the one ormore processors7 determine the unwrapped configuration2326 is the second consecutive detection, themethod2300 continues to at least one of three steps. Atstep2330, the computer executable instructions cause the one ormore processors7 to activate an audible alert, such as via a speaker and/or other electromechanical devices that produce sound connected tocontroller5 ofcompression system1. In an embodiment, the alert is a multi-toned audible alert. Atstep2332, the computer executable instructions cause the one ormore processors7 to display an error message on a display device associated with thecompression system1. At step2334, the computer executable instructions cause the one ormore processors7 to not increment a compliance time before ending themethod2300. In an embodiment, therapy usingcompression garment10 is not stopped by halting2334 the compliance time and the compliance time remains in its current state until receiving a response via a display device and/or an input device (e.g. from a human user).
• Referring toFIG. 23C, the computer executable instructions cause the one ormore processors7 to determine, atstep2336, whether the total standard deviation2314 (σ) for the entire low-pass filtered signal (e.g., 1024 samples) is greater than or equal to a wrapped threshold (e.g., 0.35). When the one ormore processors7 determine the total standard deviation is not greater than or equal to the wrapped threshold, themethod2300 continues back tostep2302. When the one ormore processors7 determine the total standard deviation is greater than or equal to the wrapped threshold, themethod2300 continues to step2338 and/orstep2340.
• In an embodiment, themethod2300 continues to step2338 in which the computer executable instructions cause the one ormore processors7 to determine whether the total standard deviation2314 (σ) for the entire low-pass filtered signal (e.g., 1024 samples) is less than or equal to a maximum limit threshold (e.g. 10.0). When the one ormore processors7 determine the total standard deviation for the entire low-pass filtered signal is not less than or equal to the maximum limit threshold, themethod2300 ends. When the one ormore processors7 determine the total standard deviation of the entire low-pass filtered signal is less than or equal to the maximum limit threshold, themethod2300 continues to step2340.
• Atstep2340, the computer executable instructions cause the one ormore processors7 to determine whether a predetermined number of segments (e.g., sample groups) into which the low-pass filtered signal has been divided are each greater than or equal to the wrapped threshold (e.g., 0.35). In an embodiment, the one ormore processors7 divide the low-pass filtered signal into five sample groups and determine2340 whether the standard deviation of each of the five sample groups is greater than or equal to the wrapped threshold. Alternatively, the one ormore processors7 divide the low-pass filtered signal into five sample groups and determine2340 whether the standard deviation of at least three of the five sample groups is greater than or equal to the wrapped threshold. When the one ormore processors7 determine each of the predetermined number of segments is not greater than or equal to the wrapped threshold, themethod2300 continues back to step2302 to re-try the cycle. When the one ormore processors7 determine each of the predetermined number of segments is greater than or equal to the wrapped threshold, the process continues to step2342 and/or step2344.
• At step2342, the computer executable instructions cause the one ormore processors7 to determine whether each of a predetermined number of segments (e.g., sample groups) into which the low-pass filtered signal has been divided are each less than or equal to the maximum limit threshold (e.g., 10.0). When the one ormore processors7 determine the predetermined number of segments (e.g., all five or at least three out of five) is each not less than or equal to the maximum limit threshold, themethod2300 ends. When the one ormore processors7 determine the predetermined number of segments is each less than or equal to the maximum limit threshold, themethod2300 continues to step2344.
• At step2344, the computer executable instructions cause the one ormore processors7 to determine whether the largest (e.g., highest amplitude) magnitude in the 0.5-4.0 Hz range of the time to frequency transformed (e.g., Fast Fourier Transform) signal is both greater than a threshold Y (e.g., 20) and less than or equal to a threshold Z (e.g., 50.0). When the one ormore processors7 determine the largest magnitude in the 0.5-4.0 Hz range is not both greater than the threshold Y and less than or equal to the threshold Z, themethod2300 ends. The one ormore processors7 determine thecompression garment10 is in a wrappedconfiguration2346 around a limb of a wearer of the garment when the one ormore processors7 determine the largest magnitude in the 0.5-4.0 Hz range is both greater than the threshold Y and less than or equal to the threshold Z. In an embodiment, the computer executable instructions cause the one ormore processors7 to declare thecompression garment10 is in a wrapped configuration (e.g., the wearer is wearing the compression garment) when the Boolean result ofstep2336 is logical true AND the result of step2338 is logical true AND the result ofstep2340 is logical true AND the result of step2342 is logical true AND the result of step2344 is logical true. Alternatively, the computer executable instructions cause the one ormore processors7 to declare thecompression garment10 is in a wrapped configuration when the Boolean result ofstep2336 is logical true AND the result ofstep2340 is logical true AND the result of step2344 is logical true.
• After determining thecompression garment10 is in the wrappedconfiguration2346, themethod2300 continues to step2348 in which the computer executable instructions cause the one ormore processors7 to increment a compliance time before ending themethod2300.
• While certain embodiments have been described, other embodiments are additionally or alternatively possible.
• While compression systems have been described as being used with thigh length compression sleeves, it should be understood that the compression systems can additionally or alternatively be used with other types of compression garments. For example, the compression systems can be used with knee-length compression sleeves and/or with sleeves having a different number of bladders configured to be disposed over different areas of the wearer's body.
• Embodiments can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations thereof. The controller of the compression system can be implemented in a computer program product tangibly embodied or stored in a machine-readable storage device for execution by a programmable processor; and method actions can be performed by a programmable processor executing a program of instructions to perform functions of the controller of the compression system by operating on input data and generating output. The controller of the compression system can be implemented in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. Each computer program can be implemented in a high-level procedural or object oriented programming language, or in assembly or machine language if desired; and in any case, the language can be a compiled or interpreted language.
• Suitable processors include, by way of example, both general and special purpose microprocessors. Generally, a processor will receive instructions and data from a read-only memory and/or a random access memory. Generally, a computer will include one or more mass storage devices for storing data files; such devices include magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and optical disks. Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD_ROM disks. Any of the foregoing can be supplemented by, or incorporated in, ASICs (application-specific integrated circuits) or FPGAs (field programmable logic arrays).
• A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. For example, while a controller with a single pressure sensor has been described, additional pressure sensors (e.g., one for each inflatable bladder) can also be used without departing from the scope of the present disclosure. Accordingly, other embodiments are within the scope of the following claims.

Claims (21)

1.-20. (canceled)

21. A compression garment controller for monitoring information indicative of pulsations associated with a heartbeat of a user, the controller comprising:

at least one computer readable storage medium configured for storing one or more monitored parameters;

one or more processors coupled to the at least one computer readable storage medium; and

computer-executable instructions embodied on the at least one computer readable storage medium, the computer-executable instructions including instructions for causing the one or more processors to:

receive information indicative of a pressure of a compression garment comprising one or more inflatable bladders from a pressure sensor during a compression therapy cycle; and

extract, from the information indicative of the pressure of the one or more inflatable bladders, information indicative of pulsations associated with the heartbeat of the wearer.

22. The compression garment controller ofclaim 21, wherein the information indicative of pulsations associated with the heartbeat of the wearer is different than an actual heart rate of the wearer.

23. The compression garment controller ofclaim 21, wherein the compression therapy treatment cycle comprises an inflation period and a pressure hold period, and the information indicative of the pressure of the one or more inflatable bladders is received during the pressure hold period.

24. The compression garment controller ofclaim 21, wherein the extracting comprises band-pass filtering the information indicative of the one or more inflatable bladders to extract signal frequencies from about 0.5 Hz to 25 Hz.

25. The compression garment controller ofclaim 24, further comprising smoothing the extracted signal frequencies following a rectangular window at five times a moving range of the extracted signal.

26. The compression garment controller ofclaim 24, further comprising verifying that a frequency range of the extracted signal is 30 beats per minute (bpm) to 240 bpm.

27. The compression garment controller ofclaim 24, further comprising detecting one or more peaks in the extracted signal, and verifying that a frequency range of the one or more peaks is 30 beats per minute (bpm) to 240 bpm.

28. The compression garment controller ofclaim 21, wherein a pressure of the compression garment is 5 to 20 mmHg.

29. A method for monitoring information indicative of pulsations associated with a heartbeat of a user, the method comprising:

receiving, from a pressure sensor, information indicative of a pressure of a compression garment comprising one or more inflatable bladders during a compression therapy cycle; and

extracting, by a controller, information indicative of pulsations associated with the heartbeat of the wearer from the information indicative of the pressure of the one or more inflatable bladders.

30. The method ofclaim 29, wherein the information indicative of pulsations associated with the heartbeat of the wearer is different than an actual heart rate of the wearer.

31. The method ofclaim 29, wherein the compression therapy treatment cycle comprises an inflation period and a pressure hold period, and the information indicative of the pressure of the one or more inflatable bladders is received during the pressure hold period.

32. The method ofclaim 29, wherein the extracting comprises band-pass filtering the information indicative of the one or more inflatable bladders to extract signal frequencies from about 0.5 Hz to 25 Hz.

33. The method ofclaim 32, further comprising smoothing the extracted signal frequencies following a rectangular window at five times a moving range of the extracted signal.

34. The method ofclaim 32, further comprising detecting one or more peaks in the extracted signal, and verifying that a frequency range of the one or more peaks is 30 beats per minute (bpm) to 240 bpm.

35. The method ofclaim 29, wherein a pressure of the compression garment is 5 to 20 mmHg.

36. A system, comprising:

a compression garment comprising one or more inflatable bladders, the compression garment configured to engage a limb of a user;

a pressure sensor communicatively coupled to the one or more inflatable bladders; and

a controller comprising at least one computer readable storage medium configured for storing one or more monitored parameters, one or more processors coupled to the at least one computer readable storage medium, and computer-executable instructions embodied on the at least one computer readable storage medium, the computer-executable instructions including instructions for causing the one or more processors to:

receive information indicative of a pressure of the one or more inflatable bladders from the pressure sensor during a compression therapy cycle; and

extract, from the information indicative of the pressure of the one or more inflatable bladders, information indicative of pulsations associated with the heartbeat of the wearer.

37. The system ofclaim 36, wherein the information indicative of pulsations associated with the heartbeat of the wearer is different than an actual heart rate of the wearer.

38. The system ofclaim 36, wherein the compression therapy treatment cycle comprises an inflation period and a pressure hold period, and the information indicative of the pressure of the one or more inflatable bladders is received during the pressure hold period.

39. The compression garment controller ofclaim 36, wherein the extracting comprises band-pass filtering the information indicative of the one or more inflatable bladders to extract signal frequencies from about 0.5 Hz to 25 Hz.

40. The compression garment controller ofclaim 36, wherein a pressure of the compression garment is 5 to 20 mmHg.

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