Surgery: kinesitherapy – Kinesitherapy – Exercising appliance
Reexamination Certificate
2002-04-29
2004-08-03
DeMille, Danton D. (Department: 3764)
Surgery: kinesitherapy
Kinesitherapy
Exercising appliance
C601S152000
Reexamination Certificate
active
06770041
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to external counterpulsation cardiac assist devices, and more particularly, to external counterpulsation cardiac assist device pressure applicators having an outer shell that resists deformation.
2. Prior Art
In the existing external counterpulsation cardiac assist device (ECPCAD) applicators (hereinafter “applicators”); limb pressure is generated by inflating balloon-like chambers that surround the limb. In addition, to keep the volume of the inflow air in check, the balloon-like chambers are encased in a relatively non-extensible fabric to minimize the bulging out of the applicator assembly.
The longitudinal and transverse cross-sections of a typical applicator as mounted on a patient thigh are shown in
FIGS. 1 and 2
, respectively. In these illustrations, the limb
100
is encased in the outer shell
102
. The space between the limb surface and the outer shell
102
is filled with a balloon
101
. Such applicator designs with the outer shell
102
consisting of relatively non-extensible fabric type of material are currently in common use. The outer shell
102
of the applicator and its underlying balloon
101
are generally made wider than usually necessary, and while applying the applicator to the limb, it is overlaid to tightly cover the limb surface and is held in place by an extended VELCRO strap (not shown) or some other similar means.
The applicator is used by laying the patient on a bed, “wrapping” the applicator around the limbs, usually the legs, the thighs, arms, buttock, etc., and affixing the outer shell
102
by VELCRO or other similar means so that the assembly stays tightly over the limbs. Part of the limb such as the ankles, knees, feet, elbows, chest area, neck and the head are not covered since due to the absence of a considerable amount of muscle mass, no significant amount of blood can be displaced by the external pressure.
The amount of fluid (i.e., gas or liquid) that is required to operate each applicator is dependent on at least several factors.
Firstly, the amount of fluid that is required to operate each applicator is dependent on the initial volume (space) between the lining and the balloon and the balloon and the limb (if any) that has to be occupied by the expanding balloon. The effects of this factor is usually countered by attempting to wrap the applicator as closely to the limb surface as possible and leaving as little as possible space (volume or void space) to be filled by the balloon during the pressure application process. This precludes so-called rigid outer shells of various forms that have a fixed inner volume and are to be used on different patients with different limb geometry even though it may be attempted to fill at least part of the gap between the patients limb and such rigid outer shells using variously shaped and various material inserts. The process of filling such gaps is extremely cumbersome and cannot fill all the existing gaps since it is almost impossible to construct the required three-dimensionally shaped inserts, particularly in the presence of highly flexible balloons that are located between the “rigid” outer shell and the limb.
The amount of fluid that is required to operate each applicator is also dependent on the amount of reduction in the volume of the segment of the limb that is enclosed by the applicator due to the applied pressure by the balloon and the level of limb surface pressure that has to be reached. These factors correspond to the desired and useful action of the applicator, which results in the blood pumping action of the device. The required airflow cannot therefore be reduced without reducing the volume of the blood that is displaced, thereby reducing the effectiveness of the applicator.
The amount of fluid that is required to operate each applicator is further dependent on the amount of increase in the applicator volume due to the expansion, bulging and change in the cross-sectional shape of its relatively non-extensible outer shell. This factor is indicative of the relative ease with which the outer shell of the applicator can expand and deform to allow its total internal volume (within which the encased segment of the limb is located) to increase with increased balloon generated internal pressure. This increase in the enclosed volume does not serve any purpose as far as the operation and performance of the applicator is concerned, and greatly reduces the efficiency of the applicator operation and it is the main source of increased demand on the air inflow to achieve the desired level of (limb) surface pressure during each cycle of its operation.
The amount of fluid that is required to operate each applicator is still further dependent on the volume of the soft tissue that may be pushed out of the sides of the applicator enclosure as the balloon is pressurized and pressure is applied to the limb segment. This factor also reduces the efficiency of the applicator by allowing some soft tissue mass to be pushed out of the enclosed volume, thereby reducing the volume of the displaced blood. In addition, the required volume of the air inflow to achieve the desired level of surface pressure is increased.
Lastly, the amount of fluid that is required to operate each applicator is still yet further dependent on the sliding of the shell down the limb towards a thinner section of the limb, thereby increasing the volume that has to be occupied by the expanding balloon. This factor greatly reduces the efficiency of the applicator by requiring a larger amount of air inflow to achieve the desired surface limb pressure.
Ideally, if the outer shell of the applicator is constructed to be rigid and to closely follow the contour of the enclosing limb surface (while allowing room for the pressure producing balloon), and prevented from shifting to the thinner side of the limb, the aforementioned increase in the internal volume of the applicator is almost totally eliminated. However, such rigid outer shells have to be constructed for each specific limb section of each individual to closely match their limb surface contour. Such relatively rigid applicator outer shells may be custom made using, for example various molding and rapid prototyping techniques known in the art, but with relatively high expense and by requiring an extended amount of time to produce the applicators for each individual patient.
SUMMARY OF THE INVENTION
Therefore it is an object of the present invention to provide a device and method for significantly reducing the aforementioned tendency of the outer shell of the applicator to expand and/or deform and thereby increase their internal volume as the internal balloon is pressurized.
Another objective of the present invention is to provide a device and method for minimizing the amount of soft tissue that is pushed out of the enclosed volume of the applicator.
Another objective of the present invention is to provide a device and method for minimizing the sliding of the applicator along the limb towards the thinner segments.
Accordingly, an applicator for applying an external counterpulsation to a body portion is provided. The applicator comprising: an outer shell for covering the body portion, the outer shell having a length in a longitudinal direction and a circumference in a circumferential direction; a balloon disposed in the outer shell, pressurization of which applies an external pressure to the body portion; and at least one anti-deformation member for reducing an amount of deformation of the outer shell caused by the pressurization of the balloon.
In a first preferred implementation, the at least one anti-deformation member preferably comprises a plurality of beam members disposed on an outer surface of the outer shell in the longitudinal direction. Preferably, the plurality of beam members are equally spaced along the circumference of the outer shell and at least one of the plurality of beam members has an I-beam cross-sectional shape.
Preferably, the plurality of beam members are disposed on the oute
Rastegar Jahangir S.
Soroff Harry
DeMille Danton D.
P.P.T.T. L.L.P
Scully Scott Murphy & Presser
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