WO2001091364A2

WO2001091364A2 - Methods, apparatus and systems for hemodynamic augmentation of cardiac massage

Info

Publication number: WO2001091364A2
Application number: PCT/US2001/015444
Authority: WO
Inventors: Robert F. Buckman; Rodney A. Brenneman
Original assignee: Theracardia, Inc.
Priority date: 2000-05-19
Filing date: 2001-05-10
Publication date: 2001-11-29
Also published as: AU2001263093A1; WO2001091364A3

Abstract

Methods, apparatus and systems for compression or counter-pulsation of the limbs and/or abdomen of a patient to augment venous return during cardiac resuscitation. In some embodiments, compression member(s) (14, 16, 18) are placed on limb(s) and/or the abdomen of the patient and are used to compress and decompress the limb(s) and/or abdomen to augment the flow of venous return blood to the patient's heart during resuscitation. The compression member(s) may be in communication with a controller (12) and the controller may be programmed to cause the compression members to alternately compress and decompress the limb(s) and/or the abdomen at desired times, intervals and/or compressive forces. Optionally, a cardiac compression sensor (22) may also be connected to the controller and the desired times or intervals for compression/decompression of the limb(s) and /or the abdomen may be linked to the rate and/or timing of cardiac compressions. One embodiment incorporates a device for minimally invasive direct cardiac compression, such device having a cardiac compression sensor linked to the controller of the system so that compression/decompression of the limb(s) and/or the abdomen may be effected in conjunction with minimally invasive direct cardiac massage.

Description

METHODS, APPARATUS AND SYSTEMS FOR HEMODYNAMIC AUGMENTATION OF CARDIAC MASSAGE

FIELD OF THE INVENTION

The present invention relates to methods and devices for cardiac massage and, more particularly, to methods and devices for compression or counter-pulsation of the abdomen and/or limbs to augment the return of venous blood to the heart during cardiac resuscitation.

BACKGROUND OF THE INVENTION A number of techniques have been developed for cardiac resuscitation. Open chest cardiac massage (OCM), wherein the patient's chest is opened surgically and the patient's heart is manually squeezed to pump blood to the body, was, prior to the 1960s, standard treatment for sudden cardiac arrest.

In the early 1960's, closed chest cardiac massage (CCM) became a standard mode of treatment for cardiac arrest. CCM involves externally compressing the chest wall and can be performed by persons who have no surgical training. Also, CCM does not carry the risk of infection or certain other complications that result from surgical opening of the patient's chest in OCM. CCM has become the standard treatment for most cardiac arrests and, when combined with respiratory/airway support, it is known as cardiopulmonary resuscitation (CPR). Although CCM is much less invasive than OCM, CCM can cause blunt trauma to the patient's heart, lungs and/or chest. More importantly, studies have shown that CCM provides significantly less cardiac output, less neuroperfusion, and less cardiac perfusion than that achieved with OCM. For example, the cardiac output generated by CCM is often 20% or less than normal, and cerebral perfusion is often approximately 10% of normal. The cardiac output with OCM is typically more than double that obtained by closed chest massage and cerebral blood flow during OCM can approach physiologic values. Jackson, R.E. et al. Hemodynamics of Cardiac Massage Emerg Med Clin North Am 1983 Dec;1(3):501-13.

More recently, methods and devices have been invented for performing minimally invasive direct cardiac massage (MID-CM). In MID-CM a small minimal access incision is made in the chest wall and an elongate cardiac compression device is inserted through the incision and is used to directly massage the heart. Examples of MID-CM procedures and devices are described in U.S. Patent Nos. 5,582,580, 5,571 ,074, and 5,484,391 to Buckman, Jr., et al.; and 5,683,364, and 5,466,221 to Zadini et al. and PCT

International Publication No. 93919856 (Theracardia, Inc.). Generally speaking, MID-CM offers the hemodynamic benefits of OCM but can be performed without forming a large thoracotomy incision and without the high potential for infections and invasiveness associated with OCM. Although OCM and MID-CM typically provide greater cardiac output than CCM, the cardiac output that can be generated by any of these procedures is still only a fraction of the normal cardiac output of a beating heart. One factor that limits the amount of cardiac output that can be generated during any form of cardiac massage is the limited amount of venous return blood that enters the heart between compressions. In view of this, several techniques have been proposed for augmenting venous return during cardiac resuscitation, thereby effectively increasing the stroke volume that will be created by each cardiac compression. One such technique for augmenting venous return is known as Interposed Abdominal Compression Cardiopulmonary Resuscitation (IAC-CPR). In IAC-CPR compressions of the abdomen are performed between compressions of the heart to cause blood within the abdomen to flow through the inferior vena cava and into the heart. In at least one study, IAC-CPR has been demonstrated to augment venous return, to improve coronary perfusion, carotid and cerebral blood flows, and to increase the rate of survival from in-hospital cardiac arrest. See, Sack, J.B. et al.; Hemodynamics, Survival Benefits, and Complications of Interposed Abdominal Compression During Cardiopulmonary Resuscitation: Acad Emerg Med 1994 Sep-Oct;1(5):490-7.

Another technique that has been thought to improve cardiac output during resuscitation is the continuous constriction of the lower limbs using military anti-shock trousers (MAST trousers), see, Hoffman, J.R.; External counterpressure and the MAST suit: current and future roles; Ann Emerg Med 1980 Aug;9(8):419-21. However, such use of MAST trousers during cardiac resuscitation has not come into widespread use. Also, U.S. Patent No.5, 806, 512 (Abramov et al.) describes the use of pneumatically controlled pressure cuffs on the legs, abdomen and optionally the chest to perform cardiac resuscitation, whereby the leg and abdominal cuffs are caused to inflate and deflate out-of-phase with the cardiac compressions thereby forcing blood into the chest cavity between cardiac compressions and allowing blood to enter the abdomen and legs between cardiac compressions. Other automated devices for cardiac resuscitation have been described in United States Patent Nos.

4,397,306 (Weisfeldt et al.), 4,424,806 (Newman et al.), 5,327,887

(Nowakowski), 5,772,613 (Gelfand et al.) and 5,833,711 (Schneider, Sr.).

Despite the above-summarized developments in the techniques and devices used for cardiac resuscitation, it is believed that there remains a need in the art for the development of improved methods and devices for increasing the hemodynamic efficiency and decreasing the complexity and/or risks of cardiac resuscitation.

SUMMARY OF THE INVENTION The present invention addresses perceived shortcomings of the prior art by providing simple, easy to use and safe devices, methods and systems for performing cardiac resuscitation with improved cardiac output and greater hemodynamic efficiency.

In accordance with the invention, there is provided a system and apparatus for aiding cardiac resuscitation in a mammalian patient comprising at least one compression member configured to engage or substantially surround a body part of the patient from which venous blood returns to the patient's heart through the patient's venous vasculature, and to alternately compress and decompress that body part so as to augment the return of blood to the heart through the venous vasculature.

In accordance with the invention, one such compression member being alternately i) expandable to a first size whereby the body part is decompressed (e.g., less compressed or not compressed at all) and ii) contractible to a second size whereby the body part is compressed (or at least more compressed than when the device is in its first size) so as to force blood from the body part, through the venous vasculature, in the direction of the patient's heart. A slip layer or slippage promoting member or substance, such as a smooth, lubricious plastic sheet, may be positioned on the patient's body between the skin and the compression member to decrease friction and to promote slippage of the contracting/expanding compression member over the patient's skin. The compression member(s) may be applied to the patient's legs, arms and/or abdomen. The compression member(s) may be connected to a controller that controls the rate and/or timing of the contraction & expansion of the pressure members. Such controller may receive input from a cardiac compression sensor that will sense when the patient's heart is being compressed and will then trigger the compression members to contract & expand in a preset ratio or preset relationship to the timing of the cardiac compressions. In cases where the invention is being used with CCM, a cardiac compression sensor may be positioned on the patient's chest and connected to the controller such that a signal will be sent to the controller each time the patient's chest is compressed. In cases where the invention is being used with MID-CM, a cardiac compression sensor may be attached to or incorporated into the device that is used to compress the patient's heart and connected to the controller such that a signal will be sent to the controller each time the patient's heart is directly compressed by the MID-CM device. Further in accordance with the invention, another embodiment of this compression member is one or more roller(s) that may be in the nature of "rolling pin(s)" that is/are placeable in contact with the desired body part (e.g., legs, abdomen, etc.) and reliable over that body part in the direction of the patient's heart to thereby augment the return of blood to the patient's heart through the venous vasculature. Such roller-type compression member(s) may be manually operated or may be mechanically and/or automatically driven.

Still further in accordance with the invention, the compression member(s) may be controlled by a programable controller that is adapted to control the rate, interval, compressive force, distance of travel (in the case of the roller embodiment) or other parameters or variables during operation of the invention.

Still further in accordance with the invention, the compression member(s) and methods summarized hereabove may be used in conjunction with either CCM, OCM or MID-CM. When used in conjunction with OCM or MID-CM, the benefits attained by the invention's augmentation of venous return may be more pronounced than with CCM due to the substantially greater cardiacoutput and right heart function achieved with OCM and/or MID- CM. In cases where the invention is used concurrently with MID-CM, a sensor may optionally be mounted on the MID-CM device and connected to a programable controller such as a microprocessor controller that controls the compression of the desired body part(s) by the compression members(s). The sensor will then send a signal to the controller each time the heart is compressed by the MID-CM device and the controller will then trigger the compression member(s) to compress the body part(s) at desired intervals or times relative to the cardiac compressions administered by the MID-CM device. Further aspects of the present invention will become apparent to those of skill in the art upon reading of the detailed description set forth herebelow and upon studying of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of a human patient who is connected to a system of the present invention having compression members for augmentation of venous return during CCM. Figure 1a is a perspective view of an optional cardiac compression sensor useable during CCM in conjunction with the system of Figure 1.

Figure 2 is a perspective view of a human patient who is connected to a system of the present invention for augmentation of venous return during MID-CM. Figure 2a is a perspective view of a the distal end of a MID-CM cardiac compression device having a cardiac compression sensor formed thereon useable during MID-CM in conjunction with the system of Figure 2.

Figure 3a is a side view of a first embodiment of a compression member device of the present invention. Figure 3b is a side view of a second embodiment of a compression device of the present invention.

Figure 3c is a side view of a third embodiment of a compression device of the present invention.

Figure 4a is a perspective view of a third embodiment of a compression device of present invention.

Figure 4b is a perspective view of a human patient on whom the device of Figure 4a is being used to augment venous return during MID-CM.

Figure 5 is a perspective view of a human patient who is connected to a system of the present invention having curass-type ampression members for augmentation of venous return during CCM, OCM or MID-CM. DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description and the figures to which it refers are provided for the purpose of describing and illustrating certain examples or embodiments the invention only, and are not intended to limit the scope of the invention in anyway.

A. A System and Method for Use in Conjunction with CCM or OCM Figure 1 shows a system 10 of the present invention comprising a controller 12 connected to thigh and lower leg compression members 14a, 14b, an abdominal compression to member 16 and upper arm and forearm compression members 18a, 18b. Each compression member 14a, 14b, 16,

18a, 18b surrounds a portion of the patient's body (e.g., an upper arm, a forearm, a thigh, a lower leg or the abdomen) and incorporates a driver 20 that operates to drive the compression member 14a, 14b, 16, 18a, 18b back and forth between an expanded configuration whereby the compression member 14a, 14b, 16, 18a, 18b does not substantially compress the underlying body part and one or more contracted configuration(s) whereby the compression member 14a, 14b, 16, 18a, 18b does substantially compress the underlying body part. It is to be appreciated that not all of these compression members 14a, 14b, 16, 18a, 18b will necessarily be used concurrently on all patients. For example, in some patients the physician or paramedic may choose to use only the abdominal compression member 16, only the thigh or lower leg compression members 14a, 14b or only one compression member on each limb instead of two on each limb as shown in Figure 1. Indeed, the number and specific position(s) of the compression members is optional and variable with each patient.

The controller 12 preferably comprises a microprocessor controller that is connected to the compression members 14a, 14b, 16,18a, 18b by way of wires or cables. The controller 12 is capable of being programmed or set by the user. Specifically, the controller 12 is adapted to receive input from the user as to the timing or frequency, as well as the order of, the contractions and expansions of the compression members 14a, 14b, 16, 18a, 18b. The controller 12 emits signals via the wires or cables to the drivers 20 causing the compression members 14a, 14b, 16, 18a, 18b to expand and contract as desired. After the controller 12 has been programmed by the operator it will control the expansion and contraction 10 of the compression members 14a,

14b, 16, 18a, 18b in a manner that requires no further input or manual handling by the operator during the cardiac resuscitation procedure.

Optionally, as shown in Figure 1a, a cardiac compression sensor 22 may also be connected to the controller 12 by way of wires 24. The cardiac compression sensor 22will send a signal to the controller 12 each time the cardiac compression is administered to the patient. In embodiments that include the optional cardiac compression sensor 22 the controller 12 may be programmed or otherwise adapted to trigger expansion and contraction of the compression members 14a, 14b, 16, 18a, 18b at a preset rate and/or in a preset sequence relative to the sensed cardiac compressions. In this regard, the operator may set to the controller 12 to cause contraction of the compression members 14a, 14b, 16, 18a, 18b after a certain number of chest compressions and to maintain such contraction for a predetermined period of time before causing the compression members 14a, 14b, 16, 18a, 18b to expand the to their expanded or relaxed configuration. For example, the controller may be programmed to cause the compression members 14a, 14b, 16, 18a, 18b to contract after each fifth cardiac compression for a period of three seconds. Alternatively, if a one-to-one ratio of cardiac compressions to peripheral compressions is desired, the operator will program the controller to cause the compression members 14a, 14b, 16, 18a, 18b to contract only during the period between cardiac compressions and to relax to their expanded configurations as each cardiac compression is being administered. Additionally, the controller 12 may be programmed or adapted to cause sequential contraction of the compression members 14a, 14b, 16, 18a, 18b such that the compression members farthest away from the heart contract first and those closest to the heart contract last. For example, in a sequential procedure the operator may program or set the controller to cause the compression members 14a, 14b, 16, 18a, 18b to contract sequentially for individual periods of three seconds, following each fifth cardiac compression. With the controller programmed in this manner, immediately after each fifth cardiac compression the lower leg compression members 14b and forearm compression members 18b will each contract for three seconds and will then relax, followed by a three second period of contraction and then relaxation of the thigh-leg compression members 14a and upper-forearm arm compression members 18a, followed by a three second period of contraction and then relaxation of the abdominal compression member 16. Such sequential contractions and relaxations of the members 14a, 14b, 16, 18a, 18b will then be repeated after each fifth cardiac compression. This sequential series of contraction and relaxation of the compression members 14a, 14b, 16, 18a, 18b will serve to force venous blood from the extremities toward the heart, thereby augmenting venous return to the heart and resulting in greater cardiac output as a result of the cardiac resuscitation.

The basic system 10, shown in Figure 1 , may be used with either CCM or OCM, however the cardiac compression sensor 22 shown in Figure 1a is primarily designed for used with CCM only. It will be appreciated that other types of cardiac compressions sensors, such as sensor pads mounted on the resuscitator's hands, may be devised for use with the system 10 in OCM. B. A System and Method for Use in Conjunction With MID-CM

Figures 3 and 3a show another system 100 of the present invention adapted for use in connection with MID-CM. This system 100 comprises the same controller 12 as described above and the same compression members 14a, 14b, 16, 18a connected to the controller 12 as described hereabove. It will be noted, however, that in this system 100 the upper arm compression members 18a (Figure 1) have been eliminated, thereby illustrating the fact that not all of the compression members shown in Figure 1 need be used in all cases.

This system 100 further comprises a MID-CM device 110 that is insertable through a minimal access incision formed in the chest of the patient and useable to directly compress and decompress the patient's heart. The preferred MID-CM device comprises an elongate, generally tubular device which can be passed through a small aperture between the patient's ribs into proximity of the patient's heart. As shown in Figures 2 and 2a, the preferred MID-CM device 110 comprises a handle 112, an elongate outer shaft 114, an inner tubular shaft 124 having a radially expandable heart contacting portion

130 on the distal end thereof. As shown in Figure 3b, the inner shaft 124 is initially disposed within and is advanceable from the outer shaft 124. A blunt dissector tip 122 extends from the inner shaft 124 and initially protrudes beyond the distal end of the outer cannula when the inner cannula 124 is fully retracted within the outer cannula 118. The blunt tip 122 preferably has a spherical surface to facilitate passage through the layer of muscle and cartilage between the ribs. After the blunt tip 122 has been pressed through the minimal access incision and into the thoracic cavity, the handle 112 is advanced distally causing the blunt tip 122 to advance into contact with the heart and allowing the heart contacting portion 130 to radially expand within the thoracic space. The heart contacting portion 130 comprises a plurality of spring struts 142 surrounded by a taut fabric cover 144 which comes into direct contact with the heart. The heart massaging operation takes place by alternately moving the heart contacting portion 130 toward and away from the heart. The timing of the massage thrusts is determined by the physician or operator of the device, and is not the subject of the present invention. This action compresses the blunt tip 122 between the taut fabric cover 144 and the patient's heart or pericardium. Optionally, a pressure or force sensor 156 is mounted on or incorporated into the MID-CM device 110, such as in its shaft 118 or blunt tip 122. This pressure sensor 156 is connected wirelessly or by way of a wire that extends through the inner cannula 124, to the controller. In this manner, a signal is sent to the controller 12 each time the MID-CM device is used to compress the patient's heart. In some cases pressure or force sensors placed elsewhere on the MID-CM device or elsewhere in or on the patient's body may be used to trigger the controller in this manner.

Once the cardiac resuscitation procedure is complete, the MID-CM device 110 is retracted from the patient's chest. More specifically, the inner shaft 124 is withdrawn proximally into the outer shaft 118 causing the heart contacting portion 130 to collapse through a mouth 150 of the outer cannula 118 such that the bunt tip 22 is once again disposed immediately adjacent the distal end of the outer cannula 118. C. Compression Members and Drivers

Referring to Figures 3a-3c, the compression members 14 may comprise any suitable type of body compressing members. Preferably, the compression members will be formed of a fabric or plastic material and will be configured to substantially surround the desired body portion (e.g., leg, arm, abdomen). Each compression member 14 may be formed in two semi- cylindrical sections 14a and 14b, one of which is positionable on one side of the body part and the other of which is positionable on the other side of the body part, such that the two sections can be alternately drawn towards one another to effect compression of the body part or allowed to move away from one another to effect decompression of the body part. An adjustable connector 32 such as a clamp or buckle may be used to attach the semi- cylindrical members 14a, 14b to each other and to adjust the resultant diameter of the compression member as to accommodate body parts of differing size.

The optional slip substance or slip members 26 may or may not be attached to the compression members 14. In the embodiment shown in the drawings, the slip members 25 preferably comprise a lubricious, biologically inert polymer film or sheet such as a polyethylene material that serves to facilitate slippage of the inner surfaces of the semi-cylindrical members 14a, 14b overthe underlying skin of the patient without causing abrasions, blisters, or irritation to the skin.

The preferred drivers 20 will move the compression members 14a, 14b, 16, 18a, 18b back and forth between their contracted and relaxed configurations with sufficient rapidity to accomplish the compression and decompression of the abdomen and or limbs of the patient at the desired rate relative to the rate of cardiac compressions. In this regard, in applications where a 1 to 1 ratio is to be maintained (i.e., 1 limb and/or abdomen compression after each cardiac compression with decompression of the limbs and/or abdomen during each cardiac compression) it will be necessary for the driver 20 to be capable of driving the compression members 14a, 14b, 16, 18a, 18b back and forth between their contracted and relaxed configurations in less than approximately 1 -3 seconds as the individual cardiac compressions administered during cardiac resuscitation are each of no more than 0.5 seconds duration with intervals of no more than 1.0 seconds between compressions. On the other hand, in applications where the ratio is 1 to 3 or more (e.g., 1 limb and/or abdomen compression after each series of 3 or more cardiac compressions with each limb and/or abdomen compression being maintained for some predetermined period of time such as 6 seconds) a slower type of driver may be used.

Figures 3a-3c show some examples of different types drivers 20 that are useable to drive the compression members 14a, 14b, 16, 18a, 18b back and forth between their contracted and relaxed configurations. Figure 3a shows a compression member 14 that incorporates a hydraulic (e.g., liquid or pneumatic) driver 20 HYD. As shown, the hydraulic driver 20 HYD comprises a cylinder 34 having a piston (not shown) mounted transversely therewithin such piston being connected to a longitudinally advanceable and retractable shaft 36. A tube 38 connects each piston 34 to a pump (not shown) and the pump is connected to the controller 12 of the system 10. The piston 34 is rigidly mounted to one of the semi-cylindrical members 14a, 14b and the distal end of the shaft 36 is connected by way of an elongate connector bar 38 to the other semi-cylindrical member of 14a, 14b. When the body part on which the compression member 14 is mounted is to be compressed, the controller 12 will cause the pump (not shown) to pump a fluid (liquid or gas) into the cylinder 34, thereby driving the piston (not shown) and longitudinal member 36 in the distal direction. Such distal movement of the longitudinal member 36 causes the connector bar 38 to pull the semi-cylindrical members 14a, 14b together or toward each other, thereby compressing the underlying body part. Thereafter, when the body part is to be decompressed, the controller 12 will cause the pump (not shown) to either stop pumping to allow back flow of fluid, or to actively withdraw fluid, from the cylinder 34 through the tube 38. This causes the piston (not shown) and shaft 36 to be withdrawn in the proximal direction (i.e., into the cylinder 34) thereby causing the connector bar 38 to push the semi-cylindrical members 14a, 14b away from each other, thereby decompressing the underlying body part.

Figure 3b shows another compression member 14 having a rotating driver 20 ROT. This rotating driver 20 ROT comprises an electric motor 40 within a housing that is rigidly mounted on one of the semi-cylindrical portions 14b. The motor 40 is connected by way of a cable 42 to the controller 12.

The electric motor 40 rotatably drives a drive shaft 44. A rotatable disk 46 is mounted on the drive shaft 44. One end of a rigid connector bar 38 is connected the other semi-cylindrical portion 14a and the other end of that connector bar 38 is pivotally attached to an off-center location on the rotatable disk 46. In this manner, rotation of the disk 46 causes the connector bar 38 to reciprocate back and forth, thereby alternately drawing the semi-cylindrical portions 14a, 14b of the compression member 14 toward one another and then away from one another. In this manner, the underlying body part is alternately compressed and decompressed. Figure 3c shows another compression member 14 having a cam driver 20 CAM. This cam driver 20 CAM comprises an electric motor 50 within a housing that is rigidly mounted on one of the semi-cylindrical portions 14b. The motor 50 is connected by way of a cable 52 to the controller 12. The electric motor 50 rotatably drives a drive shaft having a cam 54 connected thereto. One end of a rigid connector bar 38 is connected the other semi- cylindrical portion 14a and a cam follower 56 is located on the other end of the connector bar 38. The cam follower 56 is maintained in abutting contact with the outer surface of the cam 54. As the cam 54 is rotated, the cam follower 56 moves around the outer surface of the cam, thereby causing the connector bar 38 to reciprocate back and forth, thereby alternately drawing the semi- cylindrical portions 14a, 14b of the compression member 14 toward one another and then away from one another. In this manner, the underlying body part is alternately compressed and decompressed. D. Alternative Types of Body Compression and/or Venous Return

Augmentation Apparatus

It will be appreciated and that various types of apparatus, other than the compression members 14 described in detail hereabove, may be used to compress the patients lower extremities and/or abdomen or to otherwise facilitate and augment the return of venous blood to the heart during cardiopulmonary resuscitation. Furthermore, the benefit of such body compression or augmentation of venous return is much greater during OCM or MID-CM than during CCM, due to the fact that much greater cardiac output is achieved with OCM or MID-CM than with CCM and thus the benefits of augmented venous return are enhanced.

/^'. Roller Compression Device(s) Another relatively simple device 60 that may be used for compressing the lower limbs and abdomen and the patient to augment venous return is shown in Figures 4a and 4b. This device 60 comprises a roller that may be rolled by hand, or by any suitable type of drive mechanism (not shown), over the lower extremities and/or abdomen of the patient to compress those portions of the patient's body, thereby forcing blood through the veins in the direction of the heart. A particular embodiment of the device 60, shown in figures 4a and 4b, comprises a rigid bar 62 having a cylindrical pad 64 formed on a mid-portion thereof, as shown. The opposite ends of the bar 62 extend outwardly from the ends of the pad 64 so as to provide handles 66. The operator may then grasp both handles 66, place the pad 64 against the patient's legs or abdomen, and roll the device 60 in the direction of the patient's head. This movement may be repeated many times during the administration of CPR. By this movement, the roller device 60 will cause venous blood that pools in the abdomen or lower extremities to be returned through the inferior vena cava to the heart.

As discussed hereabove, the use of the device 60 will be most beneficial during OCM or MID-CM. For example, as shown in Figure 4b, a MID-CM device 110 of the type described here above may be inserted through a minimal access incision into the patient's thorax and used by a second operator to directly compress the patient's heart concurrently with use of the roller device to augment venous return.

//^'. Curass-type Compression Device(s) Figures 5-5C show curass-type compression members 302 that are usable, it in many applications, as an alternative to the other types of compression members or compression apparatus described above. As shown, the curass-type compression members 302 are positionable overthe lims and/or abdomen of the patient for the purpose of alternately compressing and decompressing the patient's limbs and abdomen. Each curass-type compression member 302 comprises a rigid outer shell 304 and at least one inflatable bladder 306 affixed to or positioned adjacent to the inner surface of the outer shell. The preferred curass-type compression members 302 are generally semi-annular and partially surround the portion of the patient's body on they are positioned. Each inflatable bladder 306 is connected by way of a tube 308 to a controller (not shown) that includes a pump or source of pressurized fluid. The controller then causes the fluid to increase and decrease in pressure, thereby causing alternate inflation and deflation of the bladders 306 in accordance with the desired timing. In this regard, Figure 5a shows the bladders 306 in their deflated state while Figure 5b shows the bladders 306 in their inflated state.

Figure 5c shows an alternative curass-type compression member 302alt that has a hinged outer shell 304alt. This hinged outer shell allows the opposite sides of the shell 304altto be spread apart to facilitate positioning of the compression member 302alt on body parts of differing size. After the compression member 302alt is positioned on the desired body part of the patient, the opposite sides of the shell 304alt are pivoted closed or toward one another and he hinge 310 is locked by way of a suitable locking apparatus (not shown), thereby holding the rigid shell 304alt in a fixed configuration. Thereafter, the controller may cause the inflation fluid to be pumped into and out of the bladder 306alt causing the desired compression and decompression of the patient's body part.

It will be appreciated, that in some embodiments multiple or compartmentalized bladders 306 may be used as shown in Figures 5a and b, while in other embodiments a single bladder 306alt may be used, as shown in Figure 5 C.

Also, one or more belts or straps (not shown) may be affixed to or passed about each curass-type compression member 302, 302alt to assist in holding it in position on the patient's body. It is to be understood that the invention has been described hereabove with reference to certain specific examples or embodiments only and no attempt has been made to exhaustively describe all possible examples and embodiments of the inventive concept. Indeed, numerous additions, deletions, modifications and alterations may be made to the above-described examples and embodiments without departing from the intended spirit and scope of the invention. Accordingly, it is intended that all such additions, deletions, modifications and alterations be included within the scope of the following claims.

Claims

1. An apparatus for aiding cardiac resuscitation in a mammalian patient, said apparatus comprising: at least one compression member configured to substantially surround a body part of the patient from which venous blood returns to the patient's heart through the patient's venous vasculature, said compression member being alternately transitionable between i) a contraction configuration whereby the body part is more compressed by the compression member so as to force blood from the body part, through the venous vasculature, in the direction of the patient's heart and ii) a non-contraction configuration whereby the body part is less compressed than when the compression member is in its first configuration.

2. An apparatus according to Claim 1 wherein the at least one compression member comprises at least one lower leg member configured to extend around the patient's lower leg.

3. An apparatus according to Claim 1 wherein the at least one compression member comprises at least one thigh member configured to extend around the patient's thigh.

4. An apparatus according to Claim 1 wherein the at least one compression member comprises at least one forearm member configured to extend around the patient's forearm.

5. An apparatus according to Claim 1 wherein the at least one compression member comprises at least one upper arm member configured to extend around the patient's upper arm.

6. An apparatus according to Claim 1 wherein the at least one compression member comprises an abdominal member configured to extend around the patient's abdomen.

7. An apparatus according to Claim 1 wherein a plurality of compression members are used and the controller is adapted to cause sequential contraction of said compression members.

8. An apparatus according to Claim 1 wherein the at least one compression member at least partially surrounds a body portion of the patient and is alternately contractable to said contraction configuration and expandable to said non-contraction configuration.

9. An apparatus according to Claim 8 wherein the at least one compression member further comprises a driver that operates to drive that compression member back and forth between its contraction configuration and its non-contraction configuration

10. An apparatus according to Claim 1 wherein the at least one compression member comprises a curass-type compression member that has a rigid outer shell and at least one inflatable bladder disposed within said rigid outer shell.

11. An apparatus according to Claim 10 wherein said at least one inflatable bladder is inflatable to cause the compression member to assume its contraction configuration and deflatable to cause that compression member to assume its non-contraction configuration.

12. An apparatus according to Claim 10 wherein said curass-type compression member further comprises a strap that extends around the body part upon which the curass-type compression member is positioned.

13. An apparatus according to Claim 10 wherein the rigid outer shell of the curass-type compression member comprises first and second shell portions connected by a hinge such that the first and second shell portions may be alternately moves away from and towards one another.

14. An apparatus according to Claim 13 wherein the hinge is lockable to prevent relative movement of the first and second shell potions after the curass-type compression member has been positioned on the desired body portion of the patient.

15. An apparatus according to Claim 1 further comprising: a slip member positioned between the patient's skin and the compression member to decrease friction between the patient's skin and the compression member as the compression member expands and contracts between its first and second configurations.

16. An apparatus according to Claim 15 wherein said slip member comprises a polymer film.

17. An apparatus according to Claim 15 wherein the controller includes a timer that causes the compression memberto alternately expand and contract at timed intervals.

18. An apparatus according to Claim 17 wherein the timer is set to cause the compression member to alternately expand and contract 1 to 120 times per minute.

19. An apparatus according to Claim 1 wherein the controller is adapted to receive input relating to the cardiac compressions being administered to the patient and wherein the controller causes the compression member to alternately expand and contract at predetermined intervals relative to the cardiac compressions being administered.

20. An apparatus according to Claim 19 further comprising a cardiac compression sensor for sensing the cardiac compressions, said cardiac compression sensor being connected to the controller, wherein the input provided to the controller relating to the cardiac compression comprises a signal from the cardiac compression sensor indicating each cardiac compression.

21. An apparatus according to Claim 20 wherein the cardiac compression sensor comprises a sensor positioned on the exterior of the patient's chest to sense closed-chest cardiac compressions.

22. An apparatus according to Claim 19 adapted for use in conjunction with a direct cardiac compression device wherein the cardiac compression sensor comprises a sensor associated with the direct cardiac compression device to indicate when the direct cardiac compression device is compressed against the heart.

23. A system comprising an apparatus according to Claim 22 further in combination with said direct cardiac compression device, said direct cardiac compression device being constructed for insertion into the thorax through an opening in the patient's body and useable to directly compress the patient's heart.

24. A system according to Claim 23 wherein the cardiac compression sensor is located on the direct cardiac compression device to sense when the direct cardiac compression device compresses the patient's heart.

25. A system according to Claim 23 wherein the direct cardiac compression device is insertable into the thorax through a minimal access incision of less than 2 inches in length.

26. A system according to Claim 25 wherein the direct cardiac compression device comprises; a handle that is graspable by a human hand; and, a cardiac compressor attached to said handle; wherein the cardiac compressor is alternately disposable in i) a stowed configuration whereby it may be passed through the minimal access incision and ii) a deployed configuration whereby it will engage the patient's heart so as to compress the heart when force is applied to the handle.

27. A system according to Claim 26 wherein the cardiac compressor portion of the direct cardiac compression device comprises: a plurality of preformed elongate members that are biased to the deployed configuration but which may be held in the stowed configuration when radially constrained; and, a sheath that is alternately positionable in first and second positions relative to the elongate members such that when in its first position the sheath radially constrains the elongate members thereby causing the elongate members to be in their stowed configuration and when in its second position the sheath does not radially constrain the elongate members thereby allowing the elongate members to assume their deployed configuration.

28. A system according to Claim 27 wherein the cardiac compression sensor comprises a pressure sensor located on the direct cardiac compression device to sense changes in pressure applied on the heart by the elongate members.

29. An apparatus according to Claim 19 wherein the controller is further operative to cause the compression member to contract 4 to 12 times per minute.

30. An apparatus according to Claim 1 wherein the compression member comprises: a first semi-circular member that extends partially around the patient's body part; a second semi-circular member that extends partially around the patient's body part; and, a compression and decompression component attached to the first and second semi-circular members and to the controller, said compression and decompression component being operative to alternately i) draw the first and second semi-circular members together to compress the body part and ii) spread the first and second semi-circular members apart to decompress the body part.

31. An apparatus according to Claim 30 wherein the compression and decompression component comprises; a shaft attached to at least one of the semi-circular members; and, at least one hydraulic piston for longitudinally driving the shaft back and forth between a first position whereby the semi-circular members are drawn together to compress the body part and a second position whereby the semi- circular members are spread apart to decompress the body part.

32. An apparatus according to Claim 30 wherein the compression and decompression component comprises; a shaft having a first end attached to at least one of the semi-circular members and a second end attached to a cam follower; a cam associated with said cam follower to alternately drive the shaft back and forth between a first position whereby the semicircular members are drawn together to compress the body part and a second position whereby the semi-circular members are spread apart to decompress the body part.

33. An apparatus according to Claim 30 wherein the compression and decompression component comprises; a shaft having a first end attached to at least one of the semi-circular members and a second end whereupon threads are formed; and, at least one rotatable drive member threadably engaged to the threads formed on the shaft for longitudinally driving the shaft back and forth between a first position whereby the semi-circular members are drawn together to compress the body part and a second position whereby the semi-circular members are spread apart to decompress the body part.

34. An apparatus according to Claim 30 wherein the compression and decompression component comprises; a shaft having a first end attached to at least one of the semi-circular members and a second end attached to a rotatable hub that has an axis of rotation, said shaft being mounted to the hub at a location that is spaced apart from the hub's axis of rotation; and, at least one drive member for rotating the hub about its axis of rotation, thereby driving the shaft back and forth between a first position whereby the semi-circular members are drawn together to compress the body part and a second position whereby the semi-circular members are spread apart to decompress the body part.

35. A method for performing cardiac resuscitation on a mammalian patient, said method comprising the steps of: (A) providing at least one compression member configured to substantially surround a body part of the patient from which venous blood returns to the patient's heart through the patient's venous vasculature, said compression member being alternately i) expandable to a first size whereby the body part is less compressed and ii) contractible to a second size whereby the body part is more compressed so as to force blood from the body part, through the venous vasculature, in the direction of the patient's heart; (B) positioning the compression member around a body part of the patient from which venous blood returns to the patient's heart; (C) applying compressions to the patient's heart; and, (D) causing the compression member to alternately contract to increase the venous return to the patient's heart.

36. A method according to Claim 35 wherein the apparatus provided in Step (A) comprises a least one leg member configured to extend around the patient's leg and wherein Step (B) comprises placing at least one leg member around one of the patient's legs.

37. A method according to Claim 35 wherein the apparatus provided in Step (A) comprises a least one arm member configured to extend around the patient's arm and wherein Step (B) comprises placing at least one arm member around one of the patient's arms.

38. A method according to Claim 35 wherein the apparatus provided in Step (A) comprises an abdominal member and wherein Step (B) comprises placing the abdominal member around the abdomen of the patient.

39. A method according to Claim 35 wherein the apparatus provided in Step (A) further comprises a controller connected to the compression member and operative to control the rate at which the compression member expands and contracts and wherein Step (D) comprises setting and actuating the controller to cause the expansion and contraction of the compression member at a desired rate.

40. A method according to Claim 35 wherein Step (C) comprises: providing a direct cardiac compression device that is insertable into the patient's chest cavity and useable to directly compress the patient's heart; creating an opening in the patient's body through which the direct cardiac compression device may be inserted into the chest cavity and into contact with the patient's heart; inserting the direct cardiac compression device through the opening formed in the patient's body and into contact with the patient's heart; and, using the direct cardiac compression device to alternately compress and decompress the patient's heart.

41. A method according to Claim 40 wherein the direct cardiac compression device has a cardiac compressor portion that is initially disposed in a stowed configuration that is small enough in diameter to pass through the opening formed in the patient's body and subsequently convertible to a deployed configuration suited for contact with and compression of the heart and wherein Step (C) further comprises: inserting the direct cardiac compression device with its cardiac compressor portion disposed in its stowed configuration through the opening formed in the patient's body; and converting the cardiac compressor portion of the direct cardiac compression device to its deployed configuration before using it to compress the patient's heart.

42. A method according to Claim 40 wherein the apparatus provided in Step (a) further comprises: a cardiac compression sensor associated with the direct cardiac compression device to sense when the patient's heart is being compressed by the device; a controller connected to the cardiac compression sensor and to the compression member, said controller being operative to receive input from the cardiac compression sensor as to the timing of the cardiac compressions and to receive input from the operator as to the desired rate of contraction and expansion of the compression member relative to the timing of the cardiac compressions sensed by the sensor, said controller being further operative to cause the compression member to contract and expand at a selected rate relative to the sensed compressions of the patient's heart; and wherein Step (D) comprises: inputting into the controller a selected rate of contraction and expansion of the compression member relative to the timing of the cardiac compressions sensed by the sensor, thereby enabling the controller to cause the compression member to contract and expand at the selected rate relative to the sensed compressions of the patient's heart.

43. A method for cardiac resuscitation of a mammalian patient, said method comprising the steps of: A. performing cardiac massage by a method selected from the group consisting of i) open cardiac massage and ii) minimally invasive direct cardiac massage; and, B. augmenting the flow of blood through the patient's venous vasculature to the right heart to enhance filling of the chambers of the heart during said cardiac massage.

44. A method according to Claim 43 wherein Step A comprises: performing open cardiac massage by creating an incision of more than 2 inches in length in the patient's body, directly contacting the heart through said incision and alternately compressing and decompressing the heart.

45. A method according to Claim 44 wherein the hands of a human resuscitator are passed through said incision into contact with the patient's heart and, thereafter, are used to alternately compress and decompress the heart.

46. A method according to Claim 43 wherein Step A comprises: performing minimally invasive direct cardiac massage by creating an incision of less than 2 inches in length in the patient's body, inserting a minimally invasive directly cardiac massage device through said incision and using said direct cardiac massage device to alternately compress and decompress the heart.

47. A method according to Claim 43 wherein Step B comprises: providing at least one compression member configured to compress a body part of the patient from which venous blood returns to the patient's heart through the patient's venous vasculature; and, using said compression member to compress the body part so as to force blood from the body part, through the venous vasculature, in the direction of the patient's heart.

48. A method according to Claim 43 wherein Step B comprises: elevating the legs of the patient above the patient's chest.

49. A method according to Claim 47 wherein said compression member is a roller, and wherein said roller is placed in contact with the body part and rolled in the direction of the patient's heart, thereby forcing blood through the venous vasculature toward the heart.

50. A method according to Claim 47 wherein the compression member is a member that at least partially surrounds the body part and wherein said compression member is used to alternately compress and decompress the body part.

51. A method according to Claim 50 wherein the compression member comprises a least one leg compression member configured to extend around the patient's leg and wherein said compression member is used to compress and decompress the patient's leg.

52. A method according to Claim 50 wherein the compression member comprises a least one arm compression member configured to extend around the patient's arm and wherein said compression member is used to compress and decompress the patient's arm.

53. A method according to Claim 50 wherein the compression member comprises a least one abdomen compression member configured to extend around the patient's abdomen and wherein said compression member is used to compress and decompress the patient's abdomen.

54. A method according to Claim 47 wherein the compression member is connected to a controller, said controller being operative to control the rate at which the compression member compresses and decompresses the body part.

55. A method according to Claim 54 wherein the method further comprises setting and actuating the controller to cause compression and decompression of the body part at a desired rate.

56. A method according to Claim 46 wherein the direct cardiac compression device has a cardiac compressor portion that is initially disposed in a stowed configuration that is small enough in diameter to pass through said incision of less than 2 inches in length and is subsequently convertible to a deployed configuration suited for contact with and compression of the heart.

57. A method according to Claim 56 further comprising: inserting the direct cardiac compression device with its cardiac compressor portion disposed in its stowed configuration through the incision formed in the patient's body; and converting the cardiac compressor portion of the direct cardiac compression device to its deployed configuration before using it to compress the patient's heart.

58. A method according to Claim 57 wherein the direct compression device further comprises: a cardiac compression sensor associated with the direct cardiac compression device to sense when the patient's heart is being compressed by the device; a controller connected to the cardiac compression sensor and to the compression member, said controller being operative to receive input from the cardiac compression sensor as to the timing of the cardiac compressions and to receive input from the operator as to the desired rate of contraction and expansion of the compression member relative to the timing of the cardiac compressions sensed by the sensor, said controller being further operative to cause the compression member to contract and expand at a selected rate relative to the sensed compressions of the patient's heart; and and wherein said method further comprises: inputting into the controller a selected rate of contraction and expansion of the compression member relative to the timing of the cardiac compressions sensed by the sensor, thereby enabling the controller to cause the compression member to contract and expand at the selected rate relative to the sensed compressions of the patient's heart.