CN1325285A - Pulse transit time measuring device and method - Google Patents

Abstract

In a method of measuring pulse transit time of a living subject, first and second pulse wave signals are generated by sensing pulses at first and second spaced pulse points. The first and second pulse wave signals are differentiated, and corresponding points (for example, points of maximum slope) of the first and second pulse wave signals are selected based on the differentiation result. The time delay between the selected two points is determined, thereby deriving the pulse transit time. A preferred apparatus measures pulse transit time using at least one fiberoptic pulse sensor that includes a fused-fiber coupling region, at least a portion of which is flexible but which is not under tension.

Description

Pulse transmission time measurement apparatus and method

The cross reference of related application

The present invention requires the interests of U.S. Provisional Application of submitting on August 24th, 1,998 60/097,618 and the U.S. Provisional Application of submitting on March 28th, 1,999 60/126,339.This two application is incorporated herein by reference.

Background of invention

The present invention relates to a kind of method and apparatus of measuring the pulse wave transmission, particularly measure the apparatus and method in people or mammiferous pulse transmission time.

People's (or mammal) pulse is a kind of capable wave disturbance of sending, propagating whole Arterial system from heart.Because the spread speed of pulse in a liquid is directly proportional with the pressure of this liquid, therefore can detect blood pressure by measuring pulse wave propagation speed.Detect the pulse transmission time, be that pulse wave transmits required time and can measure pulse wave propagation speed between two spaced apart arterial pulse points.

A people's such as the visible Trimmer of example of one blood pressure monitor system in use pulse transmission time U.S. Patent No. 4,245,648.This system use a pair of on brachial artery the piezoelectric transducer of close proximity (about 3cm) detect the propagation pulse wave.The pulse transmission time is the poor of pulse wave moment of arriving these two pick offs.

Use the described piezoelectric transducer of above-mentioned patent in practicality, to have some great deficiencies.For example, piezoelectric transducer demonstrates limited sensitivity at about 2Hz with lower frequency usually.Adult's pulse rate is generally perminute 60 and jumps or 1Hz.Baby's pulse rate generally is about per minute 120-180 and jumps or 2-3Hz.Therefore, use the performance of the system of piezoelectric transducer monitoring human can't satisfy actual needs.Another deficiency results from the following fact in practicality: piezoelectric transducer requires the position of pick off on study subject that conductive material (for example electrode and lead-in wire) is arranged.Therefore this system can't use in the environment that the existence at conductive material can throw into question.For example, because the MRL machine generates very strong radio frequency field, so conductive material can cause the serious patient burn of doing the MRL inspection.Another deficiency results from these two pick offs and leans on too closely on same tremulous pulse.This means that the pulse transmission time to be measured is very short, thereby is difficult to accurately measure.As can be seen, the measured time is short more, and a certain amount of error is big more to result's influence.

Summary of the invention

One aspect of the present invention provides a kind of method of measuring the pulse transmission time, and this method special (but being not limited to) can be used for being positioned at the pulse transducer of the pulse point of wide apart.For example, one of pick off can be positioned on the brachial artery on the other or upper arm of upper arm, and another pick off is positioned on the Radial artery on the wrist.This method relates to differentiating from the pulse wave signal of pick off to determine corresponding point, for example greatest gradient point of these two signals.Time delay between determining at these 2 then, thus draw the pulse transmission time.Two pulse wave signals are differentiated helps discerning the corresponding point of these two signals, although two pulse waves can be different slightly during wide apart as mentioned above when two sensors.In addition, can select to calculate according to this consistent markers (for example greatest gradient point) of a pulse wave like this to the pulse transmission time of next pulse wave.This advantageous particularly is because the pulse wave of each heart beating generally is different.

Another aspect of the present invention provides a kind of device of realizing said method.This device comprises that a pair of pulse transducer and handles this signal processor to the pulse wave signal of pulse transducer according to this method.

Another aspect more of the present invention provides a kind of device of measuring the pulse transmission time, comprise at least one, two pulse transducers that constitute by the variocoupler fiber optic sensor preferably, this variocoupler fiber optic sensor have an improved design as described below.This device also comprises a signal processor and can be used to realize said method or other pulse transmission time measurement methods.

From following detailed description in conjunction with the accompanying drawings, can know and find out other aspects of the present invention.

Brief description of drawings

Fig. 1 is the block diagram of pulse transmission time measurement device of the present invention.

Fig. 2 is the flow chart of the working condition of key diagram 1 system.

Fig. 3 is the block diagram of another device of the present invention.

Fig. 4 one is used for the vertical view of variocoupler fiber optic sensors of Fig. 1 and 3 devices.

Fig. 5 is the side cutaway view of Fig. 4 pick off.

Fig. 6 (Fig. 6 a-6d) illustrates the normal condition and the deflected of a pre existing tensioning straight line bonder.

Fig. 7 (Fig. 7 a-7b) illustrates-normal condition and the deflected of U-shaped corresponding circle of sensation.

Fig. 8 illustrates a variocoupler fiber optic sensor that is used for apparatus of the present invention.

Fig. 9 is the curve charts of key diagram 8 pick offs to the response of wrist pulse.

Figure 10 is another curve chart of wrist place pick off response.

Figure 11 is the exploded view that is used for another variocoupler fiber optic sensor of apparatus of the present invention.

Figure 12 is an end-view of finishing Fig. 9 pick off of assembling.

Figure 13 is that another variocoupler fiber optic sensor of being used for apparatus of the present invention is worn over the profile on the wrist.

Figure 14 is the axonometric chart that is used for a carotid artery pick off of apparatus of the present invention.

Figure 15 is the partial side view of Figure 14 pick off.

Figure 16 three-dimensional icon goes out Figure 14 pick off and the optical fibers lead-in wire of plug is housed.

Figure 17-21 curve chart illustrates pulse wave and uses Fig. 3 device to realize the corresponding pulse transmission time that method shown in Figure 2 draws.

Figure 22 illustrates the actual arrangement of Fig. 1 or Fig. 3 device.

Figure 23 illustrates the basic structure of an existing variocoupler fiber optic sensor.

The detailed description of the invention

Fig. 1 is the block diagram of pulse transmission time measurement device of the present invention.This device comprises arterial pulse pick off S1, the S2 of two any suitable forms.For example, these two pick offs can be piezoelectricity, optical fibers or any known pick off that the skin displacement that is caused by pulse (pressure) ripple is converted to the corresponding output signal of expression pulse wave.But, at least one, two pick offs variocoupler fiber optic sensor preferably for doing by following improvement design principle structure.

Pulse transducer S1, S2 are connected with a signal processor SPU, and these two signal of sensor of this signal processor processes are to determine the pulse transmission time.This signal processor can be digital signal processor or analogue signal processor as required.Certainly, as using digital processing, pick off output can send this signal processor to through analogue-to-digital converters, and perhaps, this class transducer is equipped with in this processor inside.

The following while illustrates the working condition of signal processor SPU of the present invention referring to Fig. 2.At first, instep 1, the pulse wave signal of pick off S1, S2 is imported this signal processor.Then, instep 2, this signal processor is to each pulse wave signal differentiate (differentiation).This derivative is represented the instantaneous slope of pulse wave signal certainly.Then, instep 3, this signal processor uses the result ofstep 2 to select the point with corresponding slope characteristics from these two pulse wave signals.For example, this signal processor can be selected the greatest gradient point in these two pulse wave signals.At last, instep 4, this signal processor calculates the time delay between these two Chosen Points.The time delay of being calculated constitutes this pulse transmission time.

Owing to be easy to discern the corresponding point of these two pulse wave signals from the waveform through differentiating, so said method can be conveniently used in pick off S1, the S2 of wide apart, although pulse wave is different slightly at this two sensors position.In addition, as mentioned above, also can select to calculate according to this consistent markers (for example greatest gradient point) of a pulse wave by differentiating to the pulse transmission time of next pulse wave.This advantageous particularly is because the pulse wave of each heart beating generally is different.

Fig. 3 illustrates another device of the present invention.This device comprises that a pair of its design is through following improved variocoupler fiber optic sensor S1 ', S2 '.But,, learn about that earlier the background knowledge about the variocoupler fiber optic sensor is helpful in order fully to understand the advantage of this device.

The variocoupler fiber optic sensor uses usually with stretching, merge the so-called bipyramid that technology makes and merges the convergent bonder, and in this technology, many optical fiberss at high temperature stretch and merge after (drawing).The plastic foreskin of at first peelling off on each fiber exposes the position that will form corresponding circle of sensation.These positions are also put, are usually mutually twined one and turn round or some backs of turning round remain on it and stretch in more than softening temperature in electric furnace and so on.Along with the exposed division of each fiber that stretches, they merge, and form the thin waist area or the corresponding circle of sensation that can be coupled light between each fiber.In drawing process, light is monitored to determine coupling ratio at each fiber outfan after injecting the input of one of fiber.This coupling ratio changes along with the change of the length in eel-like figure district, and drawing of fiber is up to obtaining required coupling ratio, and its amount of tension is generally and makes that the light output of each fiber is identical.This bonder can be stretched to following degree, in this eel-like figure district, the core of each fiber no longer exist and the diameter of this covering near the diameter of original core.This covering becomes one new " core ", and the evanescent field of this propagates light is forced and is surrounded this two fibers simultaneously, positive energy exchange between fiber to this new core outside.Bipyramid is merged the detailed description of convergent bonder and analyzes article " Analyse d ' un coupleurBidirectional a Fibres Optiques Monomodes Fusionners " referring to people such as J.Bures, Applied Optics (Journal of the Optical Society of America), Vol.22, No12, June15,1983, PP.1918-1922.

The advantage that bipyramid merges the convergent bonder is that crooked corresponding circle of sensation can change the output ratio.Because output is than becoming with amount of bow, so this class bonder can be used in any Application in Sensing that motion is coupled to corresponding circle of sensation.

Because whole variocoupler fiber optic sensor can make with dielectric material, coupling light to the distant place electronic installation, so they are specially adapted to sensor site and may cause the occasion of electric shock, burn, fire or blast because of conducting element is arranged.For example, at medical field, the someone proposes to do with the monitoring of variocoupler fiber optic sensor the patient's of MRL inspection heart beating.Referring to people's such as Gerdt United States Patent (USP) 5,074,309, this patent disclosure use this class pick off monitoring cardiovascular sound, comprise audible sound and inferior audible sound in a patient heart, pulse and the blood circulation.Other of variocoupler fiber optic sensor are used people's such as visible Gerdt United States Patent (USP) 4,634,858 (being applied to accelerometer), United States Patent (USP) 5,671,191 (being applied to hydrophone) and other prior aries of Gerdt.

Existing variocoupler fiber optic sensor depends on its design, in these designs, the optical-fiber coupler posttension that is straightened is fixed on the plastic supporting pieces tightly, then, is encapsulated in the elastic-like material of silicone rubber under this pre-tensioning straight line (straight) state.This encapsulating material constitutes a pressure-sensitive diaphragm, and this pressure-sensitive diaphragm can be caused this bonder bending in the corresponding circle of sensation by the external force deflection.The bending of corresponding circle of sensation causes this bonder output than changing.But the displacement that the perception diaphragm is several millimeters medium and small to 1 micron.

Figure 23 illustrates a ultimate principle that comprises the sensing device of above-mentioned variocoupler fiber optic sensor 10.In the illustrated form, pick off 10 comprise stretching two optical fiberss, merge and form eel-like figure district or corresponding circle ofsensation 13 and make-2 * 2 bipyramids and merge convergent bonder 11.The part that fibril merges into this corresponding circle of sensation one end becomes theinput fiber 12 of this pick off, and fibril leaves theoutput fiber 14 that the other end of this corresponding circle of sensation partly becomes this pick off.Label 18 expression optical fibers cores.This corresponding circle ofsensation 13 is encapsulated in one and constitutes in theelastic fluid 15 of pressure-sensitive diaphragm.The not shown support member of Fig. 1.

During use, with one of LED or semiconductor laser and so onlight source 16 irradiation input fibers 12.Luminous energy is coupled and is coupled tooutput fiber 14 afterdevice 11 is cut apart, the degree of crook of the corresponding circle of sensation that its ratio causes according to the external force that acts on the pressure-sensitive diaphragm and becoming.Available twophotodetectors 17 are measured the change cut apart of luminous energy between twooutput fibers 14, and these two photodetectors are imported adifferential amplifier 19 to the signal of telecommunication.Therefore, the output signal ofdifferential amplifier 19 represents to act on the power on the diaphragm 15.As can be seen, as only using one ofinput fiber 12 light is introduced in the pick off, another input fiber can prescind, and perhaps, also can be kept, and is standby when the primary input fiber is malfunctioning.Be noted that for simplicity's sake, shown in thebonder 11, the fiber in the corresponding circle of sensation not as mentioned above fiber twine.But, generally preferably twine mutually, to reduce the susceptiveness that goes between, lead-in wire sensitivity refers to export light and cuts apart the change that takes place with the motion of importing fiber.

Although its advantage is arranged, also there is the inherent shortcoming of pre existing tensioning straight line (straight) coupler design in existing variocoupler fiber optic sensor.One of significant drawback of existing design is that its geometry is subjected to significant limitation.Particularly, because fibre-optic lead-in wire branch is listed in the two ends of pick off, so the size of pick off is inevitable very big.When the layout of this optical fibers lead-in wire also requires to use at pick off two ends slot milling.Especially in medical applications, for example a pick off is being placed when carrying out continuous monitoring on the human body, get in the way in the size of pick off and lead-in wire position.Another shortcoming is that any displacement of corresponding circle of sensation must cause its tension force to increase.On certain point of displacement, tension force in the corresponding circle of sensation can be excessive, causes corresponding circle of sensation to break or rupture, and this bonder can't use as a result.

Get back to the present invention, Fig. 3 device uses an improved variocoupler fiber optic sensor to overcome one or more shortcomings of pre existing tensioning rectilinear transducer design.Particularly, the improvement of the employed pick off of apparatus of the present invention design makes the bending of corresponding circle of sensation without tension force.This corresponding circle of sensation preferably is arranged to U-shaped, but its structure can be more generally as the U.S. Patent application No.09/316 in the trial that coexists that is included in this as the reference material, described in 143.Use U-shaped, the two optical fiberss lead-in wire of pick off can be close to mutually, rather than is positioned at the both sides of pick off, thus avoid pre existing tensioning straight line coupler design the shortcoming of inherent above-mentioned geometry aspect.

As can be seen, by using two such pick offs, Fig. 3 device can be completely achieved the advantage that this pick off improves design.But in the present invention more in the wide region, the such pick off of use yet capable of being combined and another do not use the pulse transducer of above-mentioned improvement design, for example existing straight line variocoupler fiber optic sensor even piezoelectric transducer.

As shown in Figure 3, thecorresponding light source 40 with of each pick off S1 ', S2 ' (for example laser instrument) is connected with above-mentioned one corresponding photodetector/differential amplifier circuit 42.Each connects the output of these circuit with the corresponding input of a digital signal processor (DSP) 44 through analogue-to-digital converters 43.This input signal of this digital signal processor processes is to detect the pulse transmission time.

In combination sensor S1 ', S2 ' time, can be arranged in the optical fiber member of these two pick offs toward each other on the same supporting construction.But, as previously mentioned, arrange two pulse transducers toward each other because measured very short meeting of pulse transmission time reduces error margin.

Digital signal processor 44 may be programmed in any required mode determines the pulse transmission time, includes but not limited to the described mode in conjunction with Fig. 2.

The Figure 4 and 5 example illustrates an improved variocoupler fiberoptic sensor 20 that can use in apparatus of the present invention.This pick off can be placed on the human body, on for example chest, arm or the wrist, the skin displacement that sensing is caused by pulse.This pick off more generally sensing by the audible sound and time audible sound of cardiovascular that skin displacement manifested and breathing.

Pick off 20 comprises asupport member 22, and this support member comprises rounded nose 24 and the leader's shape elongated portion 28 that a central perforation 26 is wherein arranged.One bipyramid mergesconvergent bonder 30 and is contained on this support member, and its at least a portion (here for whole) that merges coupled zone 32 is arranged in perforation 26 and takes the shape of the letter U.The input fiber lead-in wire 34 of this bonder and output fiber lead-in wire 36 are arranged in theconduit 29 that elongated portion 28 forms abreast.Revolution two lead-in wires become corresponding circle of sensation 32 glue used behind the required form based on epoxy resin and so on suitable binder lead-in wire are cemented in this conduit for crooked 180 °.This be not subjected to tensile corresponding circle of sensation can known manner with elastomer, for example GE RTV12 and so on silicone rubber fills up perforation 26 and gives potting, forms a pressure-sensitive diaphragm 38 (not shown among Fig. 4).Also can be as mentioned below, be coated with one deck GE SS4004 (polydimethylsiloxane) and so on material on the corresponding circle of sensation, thereby need not to carry out potting with methyl silsesquioxane.This material is generally as the end agent that improves room temperature vulcanization (RTV) material bonding force from the teeth outwards.The advantage that need not potting is to improve susceptiveness, also can reduce susceptiveness because potting is thin in anycase.Support member 22 can be with lucite, polrvinyl chloride (PVC) but and so on molded plastics or other known suitable materials make.

As shown in Figure 5, the top ofdiaphragm 38 has a convex surface 39 from the supporting construction planar projection to be used for contacting human body.The convex shape of this contact surface makes pick off be the point-like probe, thereby better cardiovascular sounds to be monitored is positioned.In this pick off one embodiment, this diaphragm-operated maximum gauge is approximately identical with the diameter of a nickel coin, and the height of projection of contact surface is about half of this diameter, but diaphragm-operated size is also decided by concrete application scenario.As long as the other pars fibrosa of corresponding circle of sensation and corresponding circle of sensation is firmly supported, the size of gripper shoe can be any.The same with existing apparatus, the susceptiveness of this device is decided by diaphragm-operated rigidity.

When contact surface 39 was positioned on the brachial artery of pulse point, for example human arm or the Radial artery, 38 skin displacement relevant with pulse of diaphragm were coupled on the coupled zone 32 of optical-fiber coupler 30.Thereby this coupled zone deflection changes the light output ratio of exporting fiber 36 according to the sound of being monitored.

The deflection of Fig. 6 and 7 pairs one pre existing tensioning straight light guide fibre couplers and the deflection of the U-shaped bonder in the Figure 4 and 5 pick off compare.Fig. 6 a and 6c are respectively vertical view and the side view of corresponding circle of sensation under normal condition of existing bonder.Fig. 6 b and 6d are vertical view and the side view that is subjected to the corresponding circle of sensation of a downward force deflection.Each figure of Fig. 7 a-7d among Fig. 7 and Fig. 6 is corresponding, makes U-shaped bonder used in this invention but illustrate.

Can find out that from Fig. 7 d it is one arc that the deflection of the corresponding circle of sensation in the existing bonder causes, and corresponding circle of sensation is elongated, thereby the tension force on the corresponding circle of sensation increases.In contrast, the deflection direction of U-shaped corresponding circle of sensation is vertical with the horseshoe clamp face among Fig. 7 d, only causes U-shaped along its highly bending (horizontal dimensions among Fig. 7 d), and corresponding circle of sensation is not subjected to the tension force effect.Therefore, the displacement of corresponding circle of sensation greatly can not cause yet again and break or rupture.

Fig. 8 illustrate another variocoupler fiberoptic sensor 20 of can be used in apparatus of the present invention '.The basic structure of this pick off is same as the previously described embodiments, and just support member 22 ' be crooked about 30 a ° rectangular slab to conform to the shape of human arm/wrist, is convenient to patient and for example with belt pick off is bundled on arm/wrist.In suitable application scenario,light source 40 can be housed in the support member, photodetector/differential amplifier circuit 42 is connected to carry out the radio transmitting apparatus (not shown) of remote monitoring withcircuit 42 with one.In fact, all can be like this in above-mentioned any sensor construction.

Fig. 9 illustrates the wrist heart beating/breath signal with an experimenter of Fig. 8 pick off 20 ' acquisition.With the data flow among sampling rate acquisition Fig. 9 of 128 samples of per second.As can be seen, the pulse wave that reads with this pick off is more complicated than standard pulse reading.The amplitude structure that this pulse wave demonstrates pulse is the function of time.The amplitude structure of this pulse no longer is the function of beating of finger institute's " sensation " on a pulse point, although there is this function.In this amplitude structure, comprise all hear sounds and about breathing and reflect the information of other indexs of health.The susceptiveness that obtains with above-mentioned improvement pick off makes the pick off pulse wave of sensing complexity very well.

Figure 10 illustrates another wrist heart beating/breath signal with an experimenter of pick off 20 ' acquisition.Here, data flow is used the sampling rate digitized of one 12 analog/digital converters with 64 samples of per second.The resolution of heartbeat signal improves shown in illustration.In addition, high-visible in the whole process that is modulated at 84 seconds durations by the breathing cycle introducing.

Figure 11 and 12 illustrates another arm/wrist pick off 50 that can use in apparatus of the present invention.In this pick off, the corresponding circle ofsensation 62 of this optical-fiber coupler is not potting, but is coated with layer of material as mentioned above.These corresponding circle ofsensation 62 usefulness one are filled theelasticity pillow 68 of fluid or gel and the coupling of beating of arm/wrist (by the arrow P indication).Identical with Fig. 8, this optical-fiber coupler is contained on thegripper shoe 52, just thisgripper shoe 52 straight and not crooked (conduit of not shown for simplicity's sake input and output lead-inwire 64,66).This gripper shoe is fixed onpillow 68 the end face, and alid 69 is contained in the corresponding circle ofsensation 62 of thisbonder 60 of protection inperforation 56 on the end face of this gripper shoe.Thishole 56 makes the hydraulic pressure of beating because contacting between corresponding circle of sensation andpillow 68 end faces promotes, the deflection corresponding circle of sensation, andpillow 68 contacts corresponding circle of sensation owing to its flexibility stretches in the hole 56.One for example stick withglue bandage 57 ongripper shoe 52 the pick off tighten on arm/wrist.Label 64 and 66 is represented input fiber and output fiber respectively.

Owing to do not use pressure-sensitive diaphragm to cause susceptiveness to improve, so the non-potting design of Figure 11 and 12 is better than above-mentioned potting design.In addition, different with Fig. 8 curved design, this straight gripper shoe need not to cause the curved out-of-plane of lead-in wire light intensity to reduce.On the contrary, this bonder keeps flat shape, thus the light intensity optimum in this system.

Figure 13 is worn over profile on the wrist for using another pick off 70 in apparatus of the present invention, and this pick off comprises a frame unit 72, and the interior shape of this frame unit generally conforms to wrist as shown in the figure.This frame unit can be made with any suitable material, preferably Delrin^PVC, acrylic acid, Lucite^, Plexiglass^, styrene and so on plastics or other polymer.

The chamber 77 of adorning optical-fiber coupler 80 and gripper shoe 81 thereof in one is arranged at the top of this frame unit.Owing to this bonder is installed with this frame unit, therefore different with above-mentioned each pick off, there is this gripper shoe of input and output lead-in wire conduit to need not to comprise that a hole (for example-bore a hole) holds the corresponding circle ofsensation 82 of this bonder on it.This corresponding circle of sensation has a coating rather than potting as mentioned above.After being assembled into a module with this bonder, the available gripper shoe made from frame unit 72 same materials 81 is cemented in this chamber 77.This chamber covers with a backplate (not shown).

With beating of a fluid column 74 coupling corresponding circle of sensation and Radial artery.A pair of flexible sheet 73 and 75 are arranged on the interior outer end of this post, this post extend in frame unit 72 on the thickness between chamber 77 and the frame unit inner surface.After this bonder module assembled, corresponding circle ofsensation 82 contacted with the outer membrane 25 of this fluid column.Outer membrane is contained on the annular boss 76, to improve the height of this fluid column, to contact with corresponding circle of sensation.Can make corresponding circle of sensation prestrain slightly with contacting of outer membrane.This bonder can be made into: the prestrain of corresponding circle of sensation makes the light of two outputs between the fibers etc. cut apart, and is linear thereby dynamic range more is.The inside of this fluid column (bottom among Figure 13) is stairstepping as figure, to increase the diameter of coupled zone, wrist place.

Two diaphragms constitute a vitals of this fluid column.Because beating of Radial artery is very weak, thus the diaphragm of function admirable should be gently, approach, hardness is low and extensibility is high.Simultaneously, interior diaphragm should be enough coarse at least, contacts to bear with the continuous of skin.A kind of to can be used to make diaphragm-operated high performance material be FlexChem, and it has obtained the approval of FDA, and is durable, is the granular material of being sold by Colorite based on vinyl.But FlexChem is thermoplastic also, thereby interior diaphragm 73 can be molded, and the maximum coupled zone with Radial artery is provided, and projection is coupled better with wrist on the inner surface of frame unit 72.Can be the medical grade MDM silicone liquid that Applied Silicone Corp sells with the matching used fluid of FlexChem diaphragm.By the way, water does not preferably use with the FlexChem diaphragm, because the vapor permeable diaphragm.

For determining that the effect of pick off response has been tested the some interior diaphragms that vary in size.Particularly, having tested diameter is the diaphragm of 4mm, 7mm and 10mm, to determine the response to the stimulation that is subjected to oscillator drives of using a commercial accelerometer calibration.Frequency range (frequency range of cardiovascular and breath signal is generally 0.1-4Hz) at the about 11Hz of 0-goes up this response of investigation.Each diaphragm-operated response all meets the requirements, and the diaphragm-operated response of 10mm is best.

Get back to Figure 13, how this structure also shows packs light source and output circuit (for example photodetector and differential amplifier circuit) and so on accessory in this pick off into.Say that definitely this base part can be contained in one (as shown in the figure) or a plurality of interior chamber 79 of frame unit 72.

Figure 14-16 illustrates and is used for carotid another pick off 80.This pick off uses identical with Figure 11 straight, thegripper shoe 82 and the coupler structure that have conduit, is that corresponding circle of sensation forms a pressure-sensitive diaphragm with potting.Diaphragm area enough big (for example being about 25 cent coin sizes), with on the convex surface of pressure-sensitive diaphragm 98, increase aspherical caps 99 '.Owing to increased this spherical caps, so the sensitivity of the shaking reduction that causes when pressing against on the cervical region with the handgrip pick off of pick off.This pick off back side has aplastic cover plate 97 to be used for protecting this bonder on (bottom among Figure 14 and 15).This pick off can be fixed on the cervical region with any appropriate device, for example adhesive tape.

The input and output fibre sleeving is in a pair ofsheath 102 and 104, andsheath 102 and 104 is enclosed within again in the oversheath 106.The fibre-optic plug 108 that connects this pick off and external component is arranged on the end of lead-in wire.

Figure 17-21 comprises two brachial artery and Radial artery pulse waveform figure and the figure of corresponding pulse transmission time that obtain of Fig. 3 device of modified model variocoupler fiber optic sensor as mentioned above for using.Digital signal processor is according to programming in conjunction with the described method of Fig. 2.By the way, as can be seen, Fig. 1 and 3 devices are not mutually exclusive.For example, when programming according to Fig. 2, a kind of specific form of the structure of general expression in Fig. 3 formation picture of device 1.On the contrary, when using above-mentioned modified model variocoupler fiber optic sensor, a kind of specific form of the structure of general expression in Fig. 1 formation picture ofdevice 3.

Figure 17 illustrates the lie on the back data of eupnea of male adult.The about 50msec of pulse transmission time average out to.

The same Figure 17 of Figure 18, just to become simulation sleeping for type of respiration, air-breathing 2 seconds, exhaled 3 seconds.The pulse transmission time on average is about 35msec.

The type of respiration of Figure 19 as above, but nose pinched, and breathes and blocked.This moment blood pressure drops because the thoracic cavity is under the state of negative pressure more (pulse abnormality).This can be increased to average about 50msec from the pulse transmission time and obtain proof.

The type of respiration of Figure 20 is the same, but the air-flow total blockage.For simulation suffocates, in whole 16 second testing time, do not have in the air admission lung.Obviously as seen, the pulse transmission time increases greatly, shows that blood pressure is than the further decline of Figure 19.

Figure 21 illustrates lung and is filled air screen and firmly breathed 16 seconds.The pulse transmission time is reduced to average about 30msec, shows hypertension.

The result of Figure 17-21 is consistent with the known fact, and the lung negative pressure causes blood pressure drops, and the lung malleation causes hypertension.

Figure 22 illustrates the actual arrangement of using the variocoupler fiber optic sensor to implement Fig. 1 and 3 devices.In the illustrated form, pick off S1, S2 (S1 ', S2 ') are bundled in respectively on the pulse point of the brachial artery of arm and Radial artery with belt.The light source and the signal processing electronic device that are contained among the module M also are bundled on the arm with belt.Pick off connects through corresponding optical fibers lead wire set 34,36 with module M.Module M can comprise a radio transmitting apparatus (not shown) of communicating by letter with external electronic.

Be noted that being used in the optical fibers that uses in the sensor is high-quality photoconduction fiber, for example the light loss consumption is about the Coming SMF28 of every kilometer 0.18dB.Photodetector can be optical wavelength and is about gallium aluminum arsenide or the germanium detector of 900nm and is used for more short wavelength's silicon detector.

Photodetector can the photovoltaic mode or photoconductive mode connect.In the photovoltaic mode, available mutual transimpedance amplifier (current transitions is become voltage) connection detector and differential amplifier.The output of transimpedance amplifier also can be through filtering to eliminate broadband noise mutually.In photoconductive mode, detector can be connected with the common voltage amplifier.This moment, noise was big, reduces cost but can use requiring, but to the indifferent occasion of noise size.

Certainly, the above embodiment of the present invention is exemplary, more can make all changes to the present invention in the wide region in the present invention.

Claims (19)

1, the method in a kind of pulse transmission time of measurement one lived object comprises:

Pulse by the sensing first and second pulse points generates first and second pulse wave signals, and the described first and second pulse points are spaced apart from each other;

Described first and second pulse wave signals are differentiated;

Select the corresponding point of described first and second pulse wave signals according to the described result of differentiating; And

Detect the time delay between selected 2.

By the described method of claim 1, it is characterized in that 2, described selection comprises a bit that select the predetermined slope characteristic from each described first and second pulse wave signal.

By the described method of claim 2, it is characterized in that 3, described selection comprises a bit that select the slope maximum from each described first and second pulse wave signal.

4, by the described method of claim 1, it is characterized in that described first and second pulses point lays respectively on first tremulous pulse and second tremulous pulse.

5, by the described method of claim 4, it is characterized in that described first tremulous pulse is a brachial artery, described second tremulous pulse is a Radial artery.

6,, it is characterized in that, with a pulse with at least one pulse point in the described first and second pulse points of fiber optic sensor sensing of a fiber fusion coupled zone by the described method of claim 1.

7,, it is characterized in that at least a portion structure of described fiber fusion coupled zone makes by the described method of claim 6: its deflection and change the output of described fiber optic sensor, but described coupled zone is not subjected to the tension force effect.

8, by the described method of claim 6, it is characterized in that described fiber fusion coupled zone takes the shape of the letter U.

9, a kind of structure makes the device of realization by the described method of above-mentioned arbitrary claim.

10, the device in a kind of pulse transmission time of measurement one lived object comprises:

Be placed on first and second pulse transducers on the first pulse point and the second pulse point respectively, described first and second pulses point is spaced apart from each other;

At least one pick off in described first and second pick offs is one to comprise the fiber optic sensor of a fiber fusion coupled zone, this fiber fusion coupled zone has at least a portion, this part is made by structure: its deflection, but described coupled zone is not subjected to the tension force effect; And

One is connected and determines according to the output of described first and second pick offs signal processing unit in pulse transmission time with described first and second pulse transducers.

11, by the described device of claim 10, it is characterized in that described first and second pick offs respectively are one to have the fiber optic sensor of a fiber fusion coupled zone, this fiber fusion coupled zone has the aforesaid part of configuration.

12, by the described device of claim 10, it is characterized in that, further comprise many electrical-optical circuit of exporting the optical fibers optical coupling with a described pick off, this circuit converts the light of receiving from described output fiber to electricity output, and the level size of this electricity output is decided by the deflection of the described part of described coupled zone.

13,, it is characterized in that described electrical-optical circuit comprises a plurality ofly exports the differential amplifier circuit that is connected with the described many coupled photodetectors of output fiber optic and with described each detector respectively by the described device of claim 12.

14, by the described device of claim 10, it is characterized in that the supporting construction that a described pick off has a shape to conform to the part of people's arm.

15, the device in a kind of pulse transmission time of measurement one lived object comprises:

Be placed on first and second pulse transducers on the first pulse point and the second pulse point respectively, described first and second pulses point is spaced apart from each other;

At least one described pick off is one to comprise the fiber optic sensor of a U-shaped fiber fusion coupled zone, and

One is connected and determines according to the output of described first and second pick offs signal processing unit in pulse transmission time with described first and second pulse transducers.

16,, it is characterized in that described first and second pick offs respectively are one to have the fiber optic sensor of a U-shaped fiber fusion coupled zone by the described device of claim 15.

17, by the described device of claim 15, it is characterized in that, further comprise many electrical-optical circuit of exporting the optical fibers optical coupling with a described pick off, this circuit converts the light of receiving from described output fiber to electricity output, and the level size of this electricity output is decided by the deflection of described coupled zone.

18,, it is characterized in that described electrical-optical circuit comprises a plurality ofly exports the differential amplifier circuit that is connected with the described many coupled photodetectors of output fiber optic and with described each detector respectively by the described device of claim 17.

19, by the described device of claim 15, it is characterized in that the supporting construction that a described pick off has a shape to conform to the part of people's arm.

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