US3859989A - Therapeutic cuff - Google Patents

Abstract

A pressure cuff for medical therapeutic purposes is formed from a single walled, fluid impervious casing which is sealed to the body of a patient by one or more flexible, body-conforming, adherent flaps of thin film sheet material. Valves in the casing provide direct access to the body portion to be treated and allow maintenance of a controlled atmosphere around the body portion. A modification allows the use of both positive and negative pressures.

Description

United States Patent [1 1 Spielberg Jan. 14, 1975 THERAPEUTIC CUFF [76] Inventor: Theodore E. Spielberg, 619

Washington St., Wellesley, Mass. 02181 [22] Filed: Feb. 15, 1973 [21] Appl. No.: 332,703

Related US. Application Data [63] Continuation-impart of Ser. No. 321,313, Jan. 5,

1973, abandoned.

[52] US. Cl. 128/24 R, 128/64 [51] Int. Cl A6lh H00 [58] Field ofSearch 128/24 R, DIG. 20, 60,

[56] References Cited UNITED STATES PATENTS 1,110,494 9/1914 Kellogg 128/38 UX 1,399,095 12/1921 Webb 128/38 UX 1,629,108 5/1927 Lake 128/38 2,123,418 7/1938 Crosley et a1 128/300 3,094,983 6/1963 MacLeod 128/40 3,245,405 4/1966 Gardner.... l28/DlG. 20 3,303,841 2/1967 Dennis 128/24 R 3,421,504 1/1969 Gibbons 128/299 X FOREIGN PATENTS OR APPLICATIONS 449,304 9/1927 Germany 128/299 Primary Examiner-Lawrence W. Trapp Attorney, Agent, or Firm-Ccsari & McKcnna [57] ABSTRACT A pressure cuff for medical therapeutic purposes is formed from a single walled, fluid impervious casing which is sealed to the body of a patient by one or more flexible, body-conforming, adherent flaps of thin film sheet material. Valves in the casing provide direct access to the body portion to be treated and allow maintenance of a controlled atmosphere around the body portion. A modification allows the use of both positive and negative pressures.

12 Claims, 20 Drawing Figures "PATENTEDJANMIBYFJI I "3.859389 I SHEEHUF 4 FlG.5

PATENTEDJANWBYFI 9.959.989

SHEET 2 BF 4 FATENTED 3,859,989

sum 30F 4 FIG. l2

THERAPEUTIC CUFF This application is a continuation-in-part of my abandoned U.S. Patent Application Ser. No. 321,313, filed Jan 5, I973.

BACKGROUND OF THE INVENTION A. Field of the Invention The invention relates to a pressure cuff, and comprises a single walled pressure cuff with flexible, body conforming, adherent flaps of thin sheet material forming a fluid-type seal between the cuff wall and the body portion to which the cuff is connected.

B. Prior Art Patients confined to bed for extended periods of time are highly susceptible to blood pooling in the lower extremities which frequently leads to the formation of blood clots in the veins. To alleviate this, techniques have been developed for cyclically applying pressure to the lower extremities to assist the venous return to the heart and thereby eliminate the pooling which leads to clotting. See, for example, U.S. Pat. No. 3,391,692 whichissued to me on July 9, 1968.

The cuff used in that technique is double-walled, the inner and outer walls forming a fluid-impermeable chamber between them. This cuff is placed around the body portion to be treated, and the chamber is alternately expanded and contracted in a cyclical manner to pump the blood in the extremities back toward the heart. A travelling wave is set up by the pumping cycle to thereby establish a preferential direction for blood travel.

This cuff is highly beneficial in patient treatment, but it does have certain disadvantages. Thus, the inner wall of such a cuff is in essentially continuous contact with the body surface being treated, and can cause skin irritation if applied for extended periods of time. Further, moisture builds up at the skin surface under the cuff, thus causing further patient discomfort over extended treatment intervals. Of course, when medication is to be applied to the body portion being treated, or when it is to be inspected, the cuff must be removed. And whenever the body portion to be treated has surface lesions such as caused by a wound or a burn which would be aggravated by direct cuff contact or which would cause severe patient discomfort on such contact, the cuff cannot be used at all.

BRIEF DESCRIPTION OF THE INVENTION A. Objects of the Invention Accordingly, it is an object of the invention to provide an improved pressure cuff.

Further, it is an object of the invention to provide a pressure cuff characterized by minimal body contact surface.

A further object of the invention is to provide a pressure cuff which avoids moisture build-up at the skin surface.

Still another object of the invention is to provide a pressure cuff which allows the application of medication while maintaining pressure on the part being treated.

A further object is to provide a pressure cuff which facilitates direct inspection of the body portion being treated.

Yet another object of the invention is to provide a pressure cuff which allows the maintenance of a controlled environment of the body surface being treated. Still another object of the invention is to provide a cuff for local hyperbaric treatment for cutaneous lesions such as burns.

. Still a further object of the invention is to provide a cuff which can sustain both positive and negative pressures.

B. Summary of the Invention As used herein, the term pressure cuf denotes a shell or casing for application over a body portion and havingsealing means forming a pressurizable chamber between the casing and the body surface within the casing.

In accordance with the invention, l form a pressure cuff from a single-walled casing of limited resilience having one or more flaps of a thin, flexible, bodyconforming, adherent sheet material connected to the ends thereof and forming a seal between the casing and a body portion to be treated. The casing, as well as the end flaps, are fluid-tight, and, when properly positioned around the body portion to be treated, form a chamber surrounding the body surface. A fluid such as air or other gas is admitted into, and vented from, this chamber by means of one or more valves extending through the casing wall. These valves are connected, respectively, to a fluid source and a fluid sink. For example, one of the valves, serving as an inlet valve, may be connected to a pump for pressurizing the chamber from a fluid source, with the other valve, serving as an outlet valve, being connected in the return line of the pump or alternatively being vented to the atmosphere.

With the pressure cuff of the present invention, the body portion being treated is substantially free of contact with the casing and thus there is no surface irritation engendered as the casing is periodically pumped. The only direct contact is with the sealing flaps and these are highly conformable to the body shape so as to cause minimal discomfort. This is especially advantageous for patients having wounds or skin lesions on the body portion which is to be pressure treated. Further, the moisture which forms at the body surface is continually purged during the pumping, and a further source of patient discomfort is thus eliminated. Moreover, the temperature of the pumping fluid can be regulated to the degree desired to best accomodate patient comfort and promote healing. Indeed, medication in desired amounts and at the desired intervals may be introduced at the chamber by means of the pumping system and this medication is brought into direct contact with the body surface being treated.

The wall of the casing, as noted above, is made from a material of limited resilience. For example, the casing may be formed from a cloth wall having an inner coating or lining of rubber or plastic to render the walls substantially fluid-impermeable; this construction is the type used in conventional blood pressure cuffs. Alternatively, the casing wall may be of a completely rigid material such as molded, hard plastic or even light metal such as aluminum. Preferably, however, whether rigid or of limited flexibility, the casing wall is advantageously formed from a translucent material which facilitates inspection of the body section without removing the pressure cuff, and one of the many plastics will thus frequently be found best.

The end flaps which form the seal between the casing and the body portion being treated are formed from a thin, highly flexible, deformable, body conforming adherent sheet. Thin sheets of numerous materials, including various rubbers and plastics among others, have the desired body-conforming and body-adherent characteristics. The adherence may be primarily mechanical in nature (due to surface roughness and similar factors), or primarily physio-chemical in nature (e.g., electrostatic properties caused by molecular polarization) or both.

The thickness of each flap is of the order of a few mils (thousandths of an inch) to ensure snug conformity with the body section. The flaps, which are securely fastened to one end of the casing cuff, are of sufficient length to extend a few inches from the point of attachment and along the body surface.

Because of their body-conforming characteristic, the flaps form a seal with the body over a large area and thus do not create excessive localized and flowrestricting pressure such as may be created by an elastic type restrictive seal.

When the cuff is applied to a body portion, the flaps are folded inwardly of the casing and the chamber formed by the casing and the flaps is pressurized. The air pressure in the chamber pushes the free ends of the flaps both outwardly and against the body portion over their length; the frictional and/or electrostatic forces between the flaps and the surface of the body portion resist the outward thrust on the flaps and hold them and the casing snugly inplace. When the chamber is thus inflated, the casing is held away from the body surface and thus does not chafe or otherwise irritate it.

Valves extending through the casing allow pressurization of the chamber. This pressurization may be cyconditions the fluid (e.g., by removing moisture from it) and medicates it as desired.

As long as the cuff is to be used with pressures above atmospheric pressure a single sealing flap around the enclosed body portion is adequate. For a cuff which must accomodate both positive and negative pressures, however, a modified form of seal is provided. The modified seal has two parts, a first of which is identical to the single (positive-pressure) seal described above and a second of which is a negative pressure seal formed by a resilient sheet attached on all sides to the interior wall of the casing adjacent the body portion with which a seal is to be formed and forming a closed cell containing air or other expansible fluid. The cell normally contributes little, if anything, to sealing the cuff when the cuff is pressurized to a positive (above atmospheric) pressure, but expands and seals the cuff to the body DETAILED DESCRIPTION OF THE INVENTION The foregoing and other and further objects and features of the invention will be more readily understood from the following detailed description, when taken in conjunction with the accompanying drawings, in which:

FIG 1 is a view in perspective of one form of cuff in accordance with the present invention and prior to its application to a body section;

FIG. 2 is a view in perspective of the cuff of FIG. I applied to a leg and having a pumping and fluid treatment system connected to it;

FIG. 3 is a vertical side sectional view of the cuff of FIG. 2 taken along the lines 3-3 of FIG. 2;

FIG. 4 is a side view of another sectional embodiment of my invention showing a single walled pressure cuff having only one open end;

FIG. 5 is an end sectional view taken along the lines 5-5 of FIG. 4;

FIG. 6 is a vertical side sectional view of another embodiment of the invention utilizing a rigid shell with internal support and showing an alternative construction for attaching the sealing flaps;

FIG. 7 is an end sectional view along the lines 7-7 of FIG. 6;

FIG. 8 is a vertical side sectional view of still another embodiment of the invention showing a further alternative constr'uction for the end flaps;

FIG. 9 is an end sectional view along the lines 9-9 of FIG. 8;

FIG. 10 is a vertical side sectional view of still another embodiment of the invention showing yet another construction for attaching the end flaps;

FIG. 11 is an end sectional view along the lines 11-11 of FIG. 10;

FIG. 12 is a sketch of another form of cuff of the present invention with portions broken away for clarity, illustrating its use in providing hyperbaric treatment of the upper body, including the head;

FIG; 13 is a view in perspective of a mouth mask constructed in accordance with the present invention; and

FIG. 14 is a view in perspective of the mask in FIG. 12 as applied to the mouth of the patient.

F IG. ISA-C are side sectional views of an alternative cuff in accordance with the present invention which accomodates both positive and negative cuff pressure;

FIG. ISD is a side sectional view of an alternative embodiment of the cuff of FIGS. lSA-C.

FIG. 16 is a side sectional view of another embodiment of the cuff shown in FIG. 15; and

FIG. 17 is a side sectional view of still another embodiment of the cuff shown in FIG. 15.

In FIG. 1, one embodiment of a pressure cuff in accordance with the present invention that is especially useful for application to the lower extremities has a single-walled, outercylindrical casing 10 to which are secured end flaps l2 and 14 respectively. The casing is preferably formed from a translucent plastic material such as vinyl, while theflaps 12 and 14 are formed from a thin, flexible, body conforming, adherent sheet of material such as rubber or a silica-filled vinyl sheet (the silica providing frictional properties). The length of the flaps in the longitudinal direction-(i.e., in a direction parallel to the axis of the cylindrical cuff 10) should be of the order of 3 to 4 inches to provide sufficient sealing surface for contact with the body portion.Notches 16 may be formed around the periphery of the outer ends of theflaps 14 to assist in conforming the flaps to the smaller diameter of the body portion which they are to encompass. Valves l8 and 20 extend through thewall 12 to the interior of the cuff.

In FIG. 2, thecuff 10 of FIG. 1 is shown applied to the lower leg of a patent. The cuff completely encompasses a portion of the leg, and theflaps 14 are folded inwardly of thecasing 12 and snugly fold around the leg within the cuff. The cuff forms achamber 22 which is sealed fluid-tight by theflaps 14, 16 when the chamber is pressurized. Fluid is admitted to this chamber throughvalves 18 and 20 which are connected to apumping source 24 throughlines 26 and 28.Valves 30 and 32 respectively, are positioned in these lines. When thevalves 30 and 32 are closed, the pumpingsource 24 provides fluid under pressure to the interior of the cuff in a closed loop from thesource 24 through thevalve 30 andline 26, to the cuff l0, thence back through theline 28 andvalve 32 to thepumping source 22.Valve 32 is a three position valve which may alternatively be positioned to vent the fluid from thecasing 22.

In addition to providing pressurized fluid to thecuff 10, the pumpingsource 24 may condition the fluid it supplies. Thus, for example, thesource 24 may contain moisture extraction apparatus (not shown) to remove excessive moisture from the fluid supply to the cuff. Alternatively, it may supply moisture to the body segment within the cuff when the moisture level is too low. Additionally, it may be connected to receive medication from asource 34 and apply it in controlled and timed amounts to the body segment incuff 10. Thus, the environment of the body segment within thecuff 10 may be precisely controlled.

FIG. 3 is a cross-section of thecuff 10 of FIG. 2. As shown in FIG. 3, those portions of theflap 14 nearest thecasing 12 are bowed outwardly by the pressure within the cuff, while the ends of the flaps farthest from the casing are pushed against the body portions by the pressure within thecuff 10 and snugly conform to the body portion at the areas of contact. The snug adherence between theflaps 14 and the body portion prevent the flaps from being pushed completely out of the cuff. Thus, they form effective seals with the leg and allow pressurization of thechamber 22.

In FIG. 4, an alternative embodiment of the invention is shown in which the pressure cuff is formed from a rigid orsemi-flexible casing 40 having only a singleopen end 42 sealed by a thin, flexible, circumferentially extending, body-conformingadherent flap 44 and forming achamber 46 encompassing the leg. This form of pressure cuff is especially useful in counterpulsation treatment. Again, theflap 44 is several inches in length to allow sufflcient surface contact area with the body portion to thereby form an effective seal.Valves 48 and 50 extending through thecasing 40 provide a means of admitting fluid to thechamber 46 and discharging it from that chamber, respectively. A foot rest 52 is desirably provided to elevate the patients leg but may be pushed out of the way if desired. The cuff is sufficiently large to enable the patient to move his legs to comfortable positions as desired. Note that both legs may be enclosed within the casing simultaneously so that both can be subjected to even pressure without squeezing them together.

Turning now to FIGS. 6 and 7, thepressure cuff 60 shown there has arigid casing 62 terminating at one end in an inwardly turned generallycircular flange 64. A thin, flexible, body-conforming, adherent flap ofsheet material 66 is firmly secured to this flange, (for example, by adhesive or by thermoforming techniques) and extends inwardly several inches within the casing and in contact with the surface of the leg positioned within thecasings 62. The casing forms achamber 68 which is sealed by theflaps 66 against fluid leakage. Pressurizing fluid is admitted to the chamber by means of avalve 70 and is discharged from the chamber by means ofavalve 72. Asling 74 may be attached to the casing for providing a rest for a limb within it.

In FIGS. 8 and 9, a pressure cuff has acasing 82 with a flanged, inwardly turnedend wall portion 84 at one end thereof. Acylindrical ring 86 of dimensions somewhat larger than the maximum cross section of the body section being treated is attached to theend wall 84 and a thin, flexible, body conforming,adherent flap 88 connected to thering 86.Ring 86 lightly engages the limb positioned within it. Its purpose is to minimize any outward bowing of theflap 88 and thus this ring need not itself provide the sealing action, the latter being provided completely, or nearly completely, by theflap 88. Thecasing 82 forms achamber 90 which is sealed byflap 88. The chamber is pressurized and depressurized by means ofvalves 92 and 94, respectively. Afoot rest 96 may be provided within thecasing 82 for the patients comfort.

In FIGS. 10 and 11, a thin, flexible, circumferentially extending, body-conforming,adherent flap 100 extends between anend segment of acasing 102 and acylindrical ring 104. Thering 104 is of sufficient diameter to allow the body segment to be treated to be extended through it without discomfort, and it serves to anchor theflap 100 against outward bowing when thechamber 106 within the casing is pressurized. Thering 104 need not itself provide any sealing action and thus need not be pressed tightly against the body section. Thecasing 102 forms apressure chamber 106 which is sealed by theflap 100.Valves 108 and 110 are provided for pressurizing and depressurizing thechamber 106, respectively. Arest 112 may be provided for comfort of the patient.

FIG. 12 shows a form of pressure cuff suitable for hyperbaric treatment of patients with respiratory problems. In this instance the cuff takes the form of a preferably rigidsemi-cylindrical casing 110 with rounded top suspended on the shoulders of the patient by means ofstraps 112 and forming apressure chamber 114. The casing is, of course, preferably of a translucent meterial. A sealingflap 116 of thin, flexible, bodyconforming, adherent material such as saran extends between in-turn ed edges 118 ofcasing 110 and aring 120 of sufficient diameter of fit over the patients head. Theflap 116 is snugly engaged against the patients chest when thechamber 114 is pressurized.Valves 122 and 124 allowchamber 114 to be pressurized and depressurized, respectively.

In FIG. 12 amask 128 adapted to fit over a patients mouth is shown. The mask has a generally oval crosssection and is formed from an outer semi-flexible orrigid casing 130 having a thin, flexible, bodyconforming,adherent flap 132 attached to its rim. A pair ofvalves 134, 136 extend through thecasing 130 for pressurizing and depressurizing the interior thereof when the casing is applied against the mouth of the patient. A pair ofstraps 136, 138 are also attached to thecasing 130 for holding the casing against the mouth of the patient as shown in FIG. 14. When the cuff is applied to the patient, theflap 132 is extended inwardly toward thehousing 130. When the interior of the housing is pressurized, the flap is pushed snugly against the patients skin and forms a fluid tight seal with it.

The pressure cuff may in the same manner be advantageously used in hyperbaric treatment of the eye, since it allows free eye movement beneath it. It also may beneficially be applied as an ostomy or stoma cover (as in a colostomy, urostomy or iliostomy, and contains gas release since it forms a tighter seal as the pressure increases.

In certain types of treatment it is desirable to provide for positive as well as negative pressures within the cuff. For example, in a type of therapy known as counterpulsation therapy, one cyclically and alternately applies positive and negative pressures to a body portion to assist the pumping action of the heart and thereby relieve strains on the heart caused by its normal pumping action. The cuff of the present invention is especially suited to this type of therapy since it offers greater comfort to the patient, and the patient may therefore be placed in it for treatment for extended periods of time without undue discomfort. However, in order to accommodate negative as well as positive pressures, the sealing flap illustrated and described in connection with FIGS. 1 through 14 must be modified.

Such a modified form of seal is shown in FIGS. ISA-15C, together with a modified form of cuff which is especially suited to applying alternate positive and negative pressures toa patient. The particular type of cuff shown has a single open end and is specifically adapted to counterpulsation treatment, but it will be understoood that a cuff of the type shown in FIGS. 1-3 and open at both ends is equally well adapted to the modified seal now to be described. As shown in FIGS. ISA-15C, a cuff l is formed from a relatively inflexible or evenrigid casing 112 of sufficient size to confortably accommodate the body portion to be treated. One end of thecasing 112 is closed'by aresilient membrane 114 to form achamber 115 interior to the casing. The membrane is connected to ashaft 116 through anadapter 118. Theadapter 118 is firmly attached to themembrane 114 and pivotally connects the shaft to the membrane. Acrank arm 120 is pivotally connected toshaft 116 at one end thereof and is connected at the other end to apin 122 on the outer perimeter of awheel 124. Thewheel 124 is rotated by amotor 126. Aguide block 128 has agroove 130 in which afollower block 132 rides. Theblock 132 is connected to the pivot betweenarms 116 and 120.

Abody portion 134 such as the lower torso of a patient, is placed within thecasing 1 12. As was previously the case, afootrest 136 may be provided in the casing for the patients comfort. A thin, flexible, bodyconformingadherent flap 140 of sheet material having one edge firmly attached to anend 112a of thecasing 112 is positioned to form a fluid-tight seal with the patients body. The flap extends circumferentially around the patients body as was the case in FIGS. 1 thorugh 14 to thereby form an airtight seal with it. A flexible,resilient flap 142 also extends circumferentially around the patients body at the open end of thecuff 110. It is sealed to thecasing 112 at both its edges to form aclosed cell 144 containing an expansible gas such as air. Awall 112a of the casing extends into the casing adjacent theflap 142.

As illustrated in FIG. A, thechamber 115 is initially at atmospheric pressure. For purposes of illustration', it will be assumed that thecell 144 was closed off under atmospheric pressure so that the pressure within the cell as illustrated in FIG. 15A is also atmospheric.

Theflap 140 lies against the body and conforms lightly to its contour. Theflap 142 rests lightly against the body at the upper portion thereof, but is drawh away from the body by its own weight at the lower portion thereof. In this position, the pressure in thechamber 115 is in equalibriurn with the pressure outside this chamber and neither theflap 140 nor the flap I42 need provide any sealing action.

Turning now to FIG. 158, as themotor 126 turns thewheel 124, thearm 116 moves to the right and drives theadapter 118 to the right. This moves themembrane 114 inwardly into thechamber 115 and diminishes the free volume of this chamber, thereby causing a pressure rise within it. Theseal 140 conforms more snugly to the body portion which it encircles, and prevents escape of air from thechamber 115. At the same time, theflap 142 has a net pressure exerted on it from thechamber 115 and thus the volume of thecell 144 diminishes, while the pressure inside the cell increases. No sealing action is provided by theflap 142 in this condition; instead the entire sealing is provided by theflap 140.

As themotor 126 continues to rotate thewheel 124, theshaft 116 reverses its motion and moves to the left, thus drawing themembrane 114 outwardly of thechamber 115. This increases the effective volume of the chamber and thereby diminishes its pressure. When this occurs, air would normally move into thechamber 115 under theflap 140 and thereby break the seal otherwise provided by this flap. However, this is prevented by theseal 142 which, in response to the drop in pressure in chamber-115, expands outwardly, thereby increasing the volume ofchamber 144, and diminishing its pressure. In expanding outwardly, it presses against theflap 140 and pushes this flap firmly against thebody portion 134, thus maintaining the'effective seal betweenflap 140 and thebody portion 134. Thewall 112a ensures that theflap 142 expands against the body surface. Thus, the chamber can be dropped to a pressure below atmospheric (negative pressure), without leakage of air into it from the outside of the cuff.

As the pressure in the chamber is cycled between sub-atmospheric pressure and super-atmospheric pressure, therefore, theseals 142 and alternately become effective to provide the desired sealing action. In no event, however, is the maximum sealing pressure greater than either atmospheric pressure or the maximum pressure in thechamber 115. Further, this pressure is maintained over a substantial area and is not confined to a thin, ring-like section which may cause patient discomfort.

An alternative method of attachingflap 142 is shown in FIG. 15D. there shown, one edge of this flap is attached directly to an inner edge ofwall 1 12a; the opposite edge of this flap is attached to the rear wall ll2b of the casing. Theflap 142 forms closedchamber 144a with thewalls 112a and 11%. This chamber expands and contracts in the manner described in connection with FIGS. lSA-C to allow sealing of the open casing end under both positive and negative pressure conditions.

It is, of course, possible to omit thesealing flap 140 entirely and instead use only theflap 142 which forms and expansible chamber. In such a case, theflap 142 must effectuate a seal under both positive and negative pressure conditions. This is accomplished by first placing the body portion to be treated in the casing with thechamber 144 formed by theflap 142 collapsed to per mit this. This chamber is then pressurized to a pressure in excess of atmospheric pressure and of sufficient magnitude that it can maintain a seal with the body portion even when thechamber 115 is pressurized; it will thus also maintain a seal at or below atmospheric pressure. This type of seal may also replace theseal 14 shown in FIGS. 1-3. However, this type of seal exerts pressure above atmospheric pressure at all times, and thus will in general not be as comfortable as the seals shown in FIGS. 1 and 15 which comprise an open flap with a free end (FIGS. l14) and both an open flap with a free end and a closed flap forming an expansible chamber.

Various arrangements may also be used to provide the cyclic pressire for counterpulsation and other types of treatment. Two such alternatives are shown in FIGS. 16 and 17, respectively. In FIG. 16, theflexible membrane 114 is replaced with abellows 150 which is fluidtight sealed at anend 150a and which communicates with achamber 115 at the other end 15%. As was the case with themembrane 114, thebellows 150 is reciprocated by arod 116 to alternately raise and lower the pressure in thechamber 115 by changing the effective volume as therod 116 reciprocates.

In FIG. 17, thecasing 112 terminates in an enlarged segment 1126 which is sealed fluid-tight by a correspondinglyenlarged diaphragm 114a. This provides anenlarged chamber 115A whose effective volume is changed asrod 116 is reciprocated. By providing achamber 115A of broad diameter but narrow width, the combined effective volume ofchambers 115 and 115A (and thus the fluid pressure in these chambers) can be changed quite rapidly and over a wide range.

From the foregoing, it will be seen that I have provided an improved pressure cuff. The cuff is single walled and is readily supported away from the surface of the body portion being treated so as to prevent the discomfort normally caused by frictional contact of the cuff with the patient. A simple yet effective seal is formed on the cuff by means of one or more flaps of a flexible, thin, body-conforming, adherent sheet of material which snugly conforms to the body portion when the interior of the casing is pressurized. The sealing force is distributed over a large area in this type of seal, and this eliminates any excessive localized sealing pressure which would otherwise impede blood circulation in a patients body. The single walled casing allows direct access of the pressurizing fluid to the body surface and thus provides a convenient means for medicating this surface or otherwise controlling the atmosphere surrounding it. By utilizing a translucent material for the casing itself, continuous visual access to the surface being treated is provided.

The thickness of the sealing material is, of course, dependent on the material being used and the pressures to be applied, as well as the duration and repetition rate of the pressure application. In general, the seal must be thick enough to withstand the applied pressure and not distort excessively under it, and yet must be thin enough to snugly conform to the body section to which it is applied to thereby form a fluidtight seal. For plastic materials such as a vinyl, sheets of less than 0.005 inches thick will be found useful, while with other materials this thickness may be greater or less.

It may sometimes be found desirable to further improve both the adherent characteristics of the sealing material and its sealing ability by applying a small amount of viscous paste to the interface between the sealing flaps and the body portion. This is especially the case when the sealing material has poor (low) frictional characteristics.

It will be understood that the foregoing material is illustrative only and that various modifications may be made to the invention as described herein without departing from the spirit or the scope of the invention, the scope of the invention being defined in the claims.

Having illustrated and described my invention, I claim:

1. A therapeutic cuff for an animal body comprising A. a relatively inflexible casing for positioning over a body portion and forming a chamber therewith,

B. at least one thin, flexible, body conforming, adherent, elongated sheet having a first end thereof circumferentially attached to said casing and having a second end thereof extending radially inwardly from said casing for engagement along a substantial area, intermediate said ends, with a body positioned within said casing to thereby form a circumferentially extending fluid tight sealing flap surrounding said body portion and isolating the interior of said chamber from the exterior thereof, the diameter of said flap at its ends and all portions therebetween being greater than that of the body portion it contacts whereby said flap exerts substantially no force of its own against said body portion,

C. means forming a circumferentially extending closed auxiliary chamber on an interior wall of said casing and having a deformable wall in contact with a surface of said flap opposite the surface in contact with said body portion, said chamber being pressurized to substantially atmospheric pressure to thereby exert minimal force against said flap and said body portion when the pressure within said casing is greater than atmospheric pressure and to exert a sealing force against said flap and body portion' when the pressure in said chamber is less than atmospheric, and

D. means on said cuff for pressurizing said chamber.

2. A therapeutic cuff in accordance with claim I in which said sheet increasingly frictionally adheres to said body portion when said chamber is pressurized.

3. A therapeutic cuff in accordance withclaim 1 in which said sheet is sufficiently thin to snugly conform to a body contour it engages and sufficiently thick to withstand rupture by the chamber pressure.

4. A therapeutic cuff in accordance with claim 3 in which said sheet is formed of rubber.

5. A therapeutic cuff in accordance with claim 3 in which said sheet is formed of plastic.

6. A therapeutic cuff in accordance with claim 3 in which said sheet is formed of a plastic that is treated to increase its frictional engagement with a body surface it contacts.

7. A therapeutic cuff in accordance with claim 3 in which a viscous paste'is applied between the bodyconforming sheet and the body portion to which it is to be sealed to thereby increase adherence between said body portion and said sheet and further increase the security of the seal.

8. A therapeutic cuff in accordance withclaim 1 in which said casing is cylindrical in shape and is adapted to completely encompass said body portion.

9. A therapeutic cuff for an animal body, said cuff comprising A. a casing for forming a hollow air chamber surrounding a body portion to be treated,

B. means for extending between said casing and said body portion for sealing said chamber fluid-tight; and

C. means forming a flexible wall in said casing and of substantially larger cross section than the chamber containing the body portion to be treated and movable inwardly and outwardly of said chamber to wardly and outwardly of said chamber.

Claims (12)

1. A therapeutic cuff for an animal body comprising A. a relatively inflexible casing for positioning over a body portion and forming a chamber therewith, B. at least one thin, flexible, body conforming, adherent, elongated sheet having a first end thereof circumferentially attached to said casing and having a second end thereof extending radially inwardly from said casing for engagement along a substantial area, intermediate said ends, with a body positioned within said casing to thereby form a circumferentially extending fluid tight sealing flap surrounding said body portion and isolating the interior of said chamber from the exterior thereof, the diameter of said flap at its ends and all portions therebetween being greater than that of the body portion it contacts whereby said flap exerts substantially no force of its own against said body portion, C. means forming a circumferentially extending closed auxiliary chamber on an interior wall of said casing and having a deformable wall in contact with a surface of said flap opposite the surface in contact with said body portion, said chamber being pressurized to substantially atmospheric pressure to thereby exert minimal force against said flap and said body portion when the pressure within said casing is greater than atmospheric pressure and to exert a sealing force against said flap and body portion when the pressure in said chamber is less than atmospheric, and D. means on said cuff for pressurizing said chamber.

2. A therapeutic cuff in accordance with claim 1 in which said sheet increasingly frictionally adheres to said body portion when said chamber is pressurized.

3. A therapeutic cuff in accordance with claim 1 in which said sheet is sufficiently thin to snugly conform to a body contour it engages and sufficiently thick to withstand rupture by the chamber pressure.

4. A therapeutic cuff in accordance with claim 3 in which said sheet is formed of rubber.

5. A therapeutic cuff in accordance with claim 3 in which said sheet is formed of plastic.

6. A therapeutic cuff in accordance with claim 3 in which said sheet is formed of a plastic that is treated to increase its frictional engagement with a body surface it contacts.

7. A therapeutic cuff in accordance with claim 3 in which a viscous paste is applied between the body-conforming sheet and the body portion to which it is to be sealed to thereby increase adherence between said body portion and said sheet and further increase the security of the seal.

8. A therapeutic cuff in accordance with claim 1 in which said casing is cylindrical in shape and is adapted to completely encompass said body portion.

9. A therapeutic cuff for an animal body, said cuff comprising A. a casing for forming a hollow air chamber surrounding a body portion to be treated, B. means for extending between said casing and said body portion for sealing said chamber fluid-tight; and C. means forming a flexible wall in said casing and of substantially larger cross section than the chamber containing the body portion to be treated and movable inwardly and outwardly of said chamber to thereby change the pressure therein at a rate greater than that achievable by flexible walls of cross sectioN comparable to that of the chamber containing the body portion to be treated.

10. A therapeutic cuff according to claim 9 in which said flexible wall comprises a resilient membrane diaphragm.

11. A therapeutic cuff according to claim 9 in which said flexible wall is in the form of a bellows.

12. A therapeutic cuff according to claim 9 which includes reciprocating means for moving said wall inwardly and outwardly of said chamber.

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