Abstract:
Manual CPR apparatus allowing the application of force at two points separated by a line making a nonperpendicular angle relative to the longitudinal axis of the patient. The line separating the two force points may also lie out of the plane formed by the device&#39;s belt which circumnavigates the patient&#39;s torso. These geometrical configurations allow the facile application of the CPR force to the device by one or more operators located along the side of the patient. The device may have the capability to limit the achieved circular chest compression to one of a plurality of magnitudes. The device may also provide signals to indicate the appropriate times for applying pressure and may incorporate electrocardiogram and defibrillation components. The device may contact the patient&#39;s chest with a suction cup or other adhering component to assist in the patient&#39;s chest expanding in the interval between compressive strokes.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the priority of the PCT application PCT/US2006/027518 filed on Jul. 14, 2006, which, in turn, claimed the priority of the filing of the U.S. provisional patent application 60/699,445 filed on Jul. 15, 2005, of which the present application also claims the priority. 
     BACKGROUND 
     K. A. Kelly et al., in their U.S. Pat. No. 5,738,637, issued Apr. 14, 1998, U.S. Pat. No. 6,234,984, issued May 22, 2001, U.S. Pat. No. 6,325,771, issued Dec. 4, 2001, and U.S. Pat. No. 6,645,163, issued Nov. 11, 2003, as well as their U.S. patent application Ser. No. 9/818,102, filed Mar. 27, 2001, and U.S. patent application Ser. No. 10/705,487, filed Nov. 11, 2003, have provided a remarkable manual device for effectuating CPR on a patient suffering cardiac arrest. The disclosures of these patents and applications are incorporated here by reference. The CPR device of Kelly et al. permits the quick, correct, facile and reliable, manual application of CPR to a person suffering cardiac arrest. 
     Prior concepts of CPR have focussed on two separate lines of thought. The first of these has instructed individuals to place their hands on the chest of the person in extremis and push down in a repeated cycle. This unassisted CPR suffers from several limitations. Foremost amongst these is the fact that very few individuals, even those supposedly trained in such CPR, can accomplish the task correctly to provide a significant improvement in the patient&#39;s chances of surviving the emergency. Further, this type of CPR has only succeeded in placing a force acting downward on the chest of the victim. While this may produce some desired blood flow, it entirely ignores the significant potential of increasing circulation by constricting the person&#39;s chest. Not surprisingly, this type of CPR has not proven particularly successful in saving lives of individuals suffering cardiac arrest. 
     The second type of CPR procedure does the opposite from the first: It circumvents the individual&#39;s chest with some sort of sleeve that then undergoes constriction to squeeze the chest and increase the desired blood flow as discussed above. A pneumatic sleeve with an air pressure device often powers this type of apparatus. However, this type of CPR typically fails to a provide downward force into the chest to achieve that assist to the circulation discussed with regards to manual CPR discussed above. Further, this type of apparatus typically requires a substantial financial investment and also necessitates significant training to assure its proper attachment to a patient and subsequent operation, even when “automated.” Notwithstanding the foregoing, significantly improved examples of this type appear in U.S. Pat. No. 4,770,164 issued on Sep. 13, 1988, to R. Lach et al. as well as in the Kelly et al. patents and applications listed above. In fact, the latter show an automated apparatus accomplishing both types of CPR forces, downward and circumferential, discussed above. 
     Substantial interest has focussed on the ready use of defibrillation on persons suffering from cardiac arrest. While this process has a significant place in the treatment of such persons, it does not aid in bringing oxygen to the heart so that it can function upon defibrillation. 
     The manual CPR apparatus shown in the Kelly et al. patents and applications facilely accomplish both types of circulation assistance. It allows the downward force placed on it to pass directly into the chest of the patient to effectuate the radial force that directly depresses the chest. However, it also tightens a belt placed around the patient&#39;s chest to constrict it and the patient&#39;s chest to achieve further and important circulation around the heart muscle. 
     Significantly, the Kelly et al. device requires a minimal financial investment and virtually no training. This allows its placement in many and varied locations, such as the trunks of police squad cars and at gymnasiums and its use by individuals, such as the police themselves and others like coaches and other institutional personnel. In its simplest form, this CPR apparatus utilizes a belt placed around the victim and attached to a mechanism. When the operator pushes down on the handles forming part of this mechanism, some of the downward force passes straight through to the patient in the form of a radial force directed inward from his or her sternum into the chest. Significantly, the device converts part of the applied downward force into a tangential component that effects a circumferential tightening of the belt around the chest to squeeze it and further promote blood circulation around the heart. 
     While the Kelly et al. device described in its simplest form above has proven effective for persons with cardiac arrest, the patent and applications listed above disclose many additional features that may enhance its effectiveness in particular situations. Thus, the device may include a backboard to which the belt attaches or through slots in which the belt passes. The backboard may also have a raised portion for the patient&#39;s head, and the raised portion may house breathing apparatus and gas (such as oxygen) for the patient. 
     As other sophistications, the Kelly et al. device may include a force sensor to indicate the pressure applied to the victim&#39;s chest. An indicator of this force may then allow the operator to achieve more effective and safe treatment. 
     As a further safety feature, the apparatus may include a device for limiting the amount of circumferential tightening applied to the patient&#39;s chest. In particular, this feature may allow a choice between several different forces applied around the chest. 
     To assure full chest expansion between down strokes, Kelly et al.&#39;s device may incorporate a component on its chest-contacting surface for adhering the device to the chest. Upon the release of pressure, this adherence will assist to expand the chest by pulling up on the patient&#39;s torso. This adhering device may take the form of suction cups or even some form of adhesive. 
     Kelly et al. also suggest a signal generator forming part of their device. This component has the purpose of producing a periodic signal. This signal simply informs the operator when to push down on the apparatus and helps achieve a rhythmic application of force at the interval that portends the greatest positive effect on the patient. 
     The apparatus may also include two or more electrodes, spaced apart from each other, that contact the patient&#39;s chest at different locations for the purposes discussed below. Two electrodes may attach to the base of the device which sits on the chest. Alternately, one may attach to the base while a second connects to the belt. Or, the two may attach at different locations along the longitudinal axis of the device&#39;s belt. Or, with more, the electrodes may attach to the belt and at several locations around the belt. 
     The electrodes may serve to obtain an electrocardiogram of the patient. Alternately or additionally, the electrode may defibrillate the heart when necessary. 
     As seen from the above, the Kelly et al. device has provided vastly improve CPR to individuals in dire need of such treatment. Naturally, the work continues to improve this mechanism even further. 
     SUMMARY 
     An improved apparatus for increasing the flow of blood in a patient will typically include a base contoured to seat near a central region of a patient&#39;s chest, an actuator, and a substantially inelastic belt means configured to wrap around the patient&#39;s chest substantially in a plane. A force converter then mounts on the base and couples to the actuator. This converter has belt connectors that couple to opposite extremities of the belt means with the belt means substantially in the plane described above. The converter serves to convert into belt tightening resultants applied to the belt connectors and directed substantially tangentially to the chest a force applied to the actuator at two separated points along a line making a nonzero angle to the plane of the belt means and directed toward the chest. 
     The Kelly et al. device carried two handles for the operator to apply a force to by pushing down on at separated locations for the CPR. The handles were separated by a line that actually lay in the plane defined by the belt. Stated in other words, the separation between the handles lies across the patient&#39;s chest, or, more accurately, perpendicular to the patient&#39;s longitudinal axis. This then requires the operator to straddle the patient or to try to configure his or her own body in an unnatural configuration to achieve the downward force on the two handles. The new device described above obviates this problem from the Kelly et al. device by moving the separation of the handles away from the plane of the belt that circumnavigates the patient&#39;s chest. This allows the operator to assume a more natural position along the side of the patient. 
     More particularly, the line separating the two handles may lie substantially perpendicular to the plane of the belt means. Stated alternately, the line separating the two handles, or the force points, lies substantially parallel to the longitudinal axis of the patient&#39;s torso. In either instance, the operator may facilely grab the handles to perform the life-saving function. 
     Rather than focussing upon the plane of the belt means that circumvents the patient, a description of an improved CPR device may focus on the points of attachment of the opposite extremities of the belt means to the belt connectors of the force converter. These two points generally define a first line. The converter then converts into belt tightening resultants applied to the belt connectors directed substantially tangentially to the chest a force applied to the actuator at two separated points along a second line making a nonzero angle to the first line and directed toward the chest. As suggested above, the preferred location of the second line along which the operator applies his or her force lies substantially perpendicular to the first line defined by the points of attachment of the opposite extremities of the belt means to the belt connectors of the converter. Or, the first line along which the operator applies the force lies substantially parallel to the longitudinal axis of the torso of said patient. 
     A method of CPR treating a patient, as indicated above, commences with seating a base of a blood flow increasing apparatus on a patient&#39;s chest near a central region of that chest. It then includes wrapping a belt means with first and second opposite extremities around the patient&#39;s chest, with the belt means itself substantially forming a plane. Any of the extremities of the belt means not already fastened to the apparatus are, accordingly, fastened to it, with the belt means substantially forming a plane. At this point, a force is applied at two separated points along a line making a nonzero angle with the plane defined above and directed toward the chest to an actuator coupled to a converter. The converter is, of course, coupled to the base and the belt means. Lastly, the force is converted into belt tightening resultants directed substantially tangentially to the chest. 
     Preferably, the line along which the force is applied lies substantially perpendicular to the plane defined by the belt means. Or, this line lies substantially parallel to the longitudinal axis of the patient&#39;s torso. 
     Alternately, the first and second extremities of the belt means are separated from each other substantially along a first line when fastened to the apparatus. A force is then applied toward the chest at two separated points along a second line making a nonzero angle relative to the first line and directed to an actuator coupled to a converter which in turn couples to the base and the belt means. Lastly, the force is converted into belt tightening resultants directed substantially tangentially to the chest. As above, the first line may lie substantially perpendicular to the second line, or alternately, substantially parallel to the longitudinal axis of the patient&#39;s torso. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  shows an operator employing an improved device to administer CPR force from the side of a patient and along a line parallel to the patient&#39;s torso. 
         FIG. 2  gives an end view along the line  2 - 2  of the CPR device of  FIG. 1  but without the operator. 
         FIG. 3  provides a similar view of the CPR device of  FIGS. 1 and 2  but with a downward force exerted on the device&#39;s handles. 
         FIG. 4  shows an isometric view of the CPR apparatus of  FIGS. 1 to 3 . 
         FIG. 5  displays the components of the CPR device of  FIGS. 1 to 4  in exploded view. 
         FIG. 6  gives an isometric view of the CPR apparatus of  FIGS. 1 to 4  and very similar to that of  FIG. 4  in particular but in a depressed, or compressive, state. 
         FIG. 7  illustrates a CPR device the same as that in  FIGS. 1 to 6  with a view very similar to that in  FIG. 3  but including the use of a backboard. 
         FIG. 8  shows, in an isometric view, a CPR device allowing the application of any of a number of preselected CPR forces somewhat similar to that seen in  FIGS. 13 to 17  of the incorporated Kelly et al. patents and applications but permitting the location of the force at any two points around a circle relative the patient&#39;s torso. 
         FIG. 9  gives an end elevational view along the line  9 - 9  of the CPR device shown in  FIG. 8  with the compressive configuration in phantom. 
         FIG. 10  provides an isometric view of a CPR apparatus utilizing a converting unit similar to that of  FIGS. 1 to 7  but allowing the application of force at any two points around a circle over the patient&#39;s torso. 
         FIG. 11  portrays a side elevational view along the line  11 - 11  of the CPR device of  FIG. 10 . 
         FIG. 12  gives an end elevational view along the line  12 - 12  of the CPR device of  FIG. 10  and showing the compressive state in phantom. 
         FIG. 13  has an enlarged view along the line  13 - 13  of the belt attaching mechanism of the CPR apparatus of  FIG. 10 . 
         FIG. 14  provides an isometric view of an alternate CPR apparatus allowing the application of force along a line parallel to the patient&#39;s torso and in which the belt ends raise upward upon the application of a compressive force. 
         FIG. 15  has the same view of the same CPR apparatus of  FIG. 14  but with the belt and one side removed to illustrate the working of that device&#39;s mechanism. 
         FIG. 16  gives a cross-sectional view along the line  16 - 16  of the CPR device of  FIG. 14 . 
         FIG. 17  portrays a CPR device virtually identical to that of  FIGS. 14 to 16  except that it uses a suction cup to contact the patient&#39;s chest to assist in chest expansion between force applications. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 to 7  show the CPR device generally at  30  attached by the belt  31  to the patient  32  undergoing CPR treatment. As seen particularly in  FIGS. 1 to 3 and 7 , the belt  31  generally defines a plane as it circumvents the patient  32 . The handles  33  and  34  of the CPR device  30  lie (and are separated from each other) along the line  35 . The line  35 , in turn, generally forms a perpendicular angle with the plane of the belt  31 . It also lies generally parallel to the longitudinal axis  36  of the patient  32 . 
     This orientation of the handles  33  and  34  allows the operator  40  to kneel or otherwise position himself or herself along the side of the patient  32  and facilely place his or her hands  41  and  42  on the handles  33  and  34 , respectively, to effectuate CPR. The operator  40  need not straddle the patient  32  or assume some other inconvenient or less effective position. 
     To administer CPR, the operator  40  places the belt  31  around the patient&#39;s back and the apparatus  30  on the patients&#39; chest. He or she then attaches the belt ends  45  and  46  to the device  30 . Specifically, the ends  45  and  46  wrap around the rods  47  and  48  and attach there using such standard couplings such as hooks and loops, any of the connections shown in Kelly et al.&#39;s patents and applications, or the quick release clamp discussed below with regards specifically to  FIG. 13 . This produces the configuration shown in particular in  FIGS. 1, 2, and 4 . 
     The operator then pushes downward on the handles  33  and  34 . This accomplishes two tasks. First, the device  30  transmits a downward force directly onto the sternum of the patient  32  to directly compress the chest. This provides the first component of the CPR. 
     Second, pushing down on the handles  33  and  34  forces their interconnecting bar  53  to descend, with its bearings  55  and  56 , along the openings  57  and  58  in the sides  59  and  60 , respectively, of the U-bar  61 , permanently affixed to the base  62 . The bar  53 , in turn, surrounded by the bearings  65  and  66 , passes through the openings  67  and  68  in the triangular side plates  69  and  70 , respectively, as clearly seen in  FIG. 5 . Thus, pushing down on the handles  33  and  34  causes the bar  53  to force the side plates  69  and  70  to travel downwards as well. 
     The plates  69  and  70  moving up and down forces the levers  75  to  78  to rotate around their respective pivot points  81  to  84 , respectively. To see this, the bolt  85  journals the pivot points  81  and  83  of the side plates  75  and  77 , respectively, to the opening  89  in the base  62  while similarly the bolt  86  rotatingly connects the pivot points  82  and  84  to the base  62 . In turn, the bolt  91  passes through the slot  93  in the side plate and journals to the upper arm  95  of the lever  75 . With the bar  53  in its raised position, the bolt  85  sits towards the interior of the side plate  69  as particularly seen in  FIGS. 2 and 4 . Pushing down on the handles  33  and  34  forces the plate  69  to move in the same direction which, concomitantly, forces the bolt  91  to move downward and, at the same time, towards the outside of the slot  93 . This forces the lever  75  to rotate in the counterclockwise direction in  FIGS. 4 and 5 , the upper arm  95  of the lever  75  to move downward, and the lower lever arm  97  to travel upward all around the pivot point  81  to the position seen in  FIGS. 3, 6, and 7 . 
     Exactly the same takes place with regards to the lever  76  which has its upper arm  102  slidingly affixed to the side plate  70  by the bolt  104  which passes through the slot  106  and moves along it. An exactly analogous analysis shows that pushing down on the handles  33  and  34  causes the lever  76  to rotate in the counterclockwise direction, in  FIGS. 4 and 5 , its upper arm  102  to descend, and its lower arm  108  to elevate. Thus, in summary, pushing down on the handles  33  and  34  forces the lower arms  97  and  108  of the levers  75  and  76 , respectively, to raise. However, the bar  48 , to which the end  45  of the belt  31  attaches, is itself connected to the lower lever arms  97  and  108 . Thus, pushing down on the handles  33  and  34  raises the belt end  45  and tightens the belt  31 . 
     Exactly the same thing happens to the other belt end  46 . Pushing down on the handles  33  and  34  causes it to also raise and tighten the belt  31 . As a consequence, a downward force on the handles  33  and  34  both depresses the chest of the patient and tightens the belt around it, as seen in  FIGS. 3 and 7 . 
     The latter  FIG. 7  shows the use of the CPR device  30  on a patient  32  placed on the backboard  121 . As seen there, the belt  31  passes through the two openings  123  and  124 . To facilitate the use of the CPR apparatus  30 , the backboard may permit the semipermanent attachment of the belt  31  for quicker use when needed. The backboard  121  may contain any or all of the features shown for such an item in the patents and applications of Kelly et al. 
     Additionally, as seen in  FIGS. 4 and 5 , the lockpin  127  fits into the opening  128  of the side plate  69 , and with the handles  33  and  34  in their raised position, the openings  129 ,  130 , and  131  of the levers  75  and  77 , and the U-bar  59 , respectively. This keeps the device  30  in the elevated configuration shown in  FIG. 4  to permit the taut attachment of the belt  31  immediately prior to use and prevent possibly deleterious movement when not in use. 
     As seen in the above figures, the levers  75  to  78  have the unique shape of T-bases with the upper arms bent 90 degrees to the horizontal (as seen there). This allows the upper arms to move to their descended positions seen in  FIGS. 3, 6, and 7  without interfering the raising of the ends  47  and  48  holding the belt ends  45  and  46  to tighten the belt  31 . In the tightened position seen in these figures, the bars  45  and  46  actually nestle in the 90 degree bends of the upper lever arms. 
       FIGS. 8 and 9  show a CPR device generally at  150  built upon the unit shown in  FIGS. 13 to 17  of the Kelly et al. patents and applications. Without repeating the analysis contained there, the device has the two over-center levers  151  and  152  that pivot about the point  153 . The belt ends attach to the bars  157  and  158  connected to the respective lever arms  159  and  160  of the levers  151  and  152 . As seen from the perspective of  FIG. 9 , the belt end from the right in the figure will attach to the bar  157  and the belt end from the left attaches to the bar  158 . In turn, the lever arm  159  separates the bar  157  (and the right belt end) from the pivot point  153  and the lever arm  160  does the same action for the left-belt-end bar  158 . 
     As the levers  151  and  152  pivot about the point  153 , the bars  157  and  158  move upward and towards each other. This causes the ends of the belt attached to these bars to similarly move upwards and toward each other and tighten the belt about the torso of the CPR patient. 
     The stop pin  163  serves to limit the amount of rotation of the levers  151  and  152  about the pivot point  153 . In particular, placing the pin  163  in the opening  164  permits the least amount of such rotation while placing it in the openings  165  and  166  allows ever increasing rotation and thus tightening of the belt about the patient&#39;s chest. Removing the pin  163  eliminates the barrier to rotation altogether should that prove necessary. 
     To operate the CPR device  150 , the attendant pushes down on the wheel  171 . The exact location where the operator places his or her hands does not matter to any particular degree. However, for balance, locating the pressure points on generally opposite sides of the wheel  171  would appear somewhat desirable. In particular, the wheel  171  permits placing the hands at two locations separated by a line lying generally parallel to the bars  157  and  158 . However, these bars  157  and  158 , with the belt surrounding the patient&#39;s chest and attached to them, lie generally parallel to the patient&#39;s longitudinal axis and also perpendicular to the plane defined by the belt circumnavigating the patient. The two posts  173  and  174  rigidly attach the wheel  171  to the side plate  175 , and the posts  177  and  178  connect it to the plate  179 . Thus, the operator&#39;s pushing down on the wheel causes the side plates  175  and  179  to descend. It also causes a downward pressure on the patient&#39;s chest. 
     As the side plates  175  and  179  descend, they similarly cause the rod  181 , coupled to the upper lever arms  159  by the caps  183  which also pass through the slots  185 , to move downward. At the same time, the rod  188 , coupled to the plates  175  and  179  by the caps  190  which pass through the slots  192 , also goes down and takes with it the upper lever arms  160 . Thus, pushing down on the wheel  171  at any points around its circumference causes the levers  151  and  152  to pivot about the point  153  which has the effect of pulling up on the belt ends by the  157  and  158  to tighten it circumferentially about the patient&#39;s chest. This action is in addition to the direct downward force exerted on the patient&#39;s chest discussed above. 
       FIGS. 10 to 12  show the CPR apparatus generally at  201  that operates in virtually the same manner as the device  30  in  FIGS. 1 to 7  and includes a substantial number of important additional features. Initially, the manual operation of the apparatus  201  involves the attendant pushing down on the wheel  202 . The wheel  202 , in turn rigidly connects to the side plates  203  and  204  though the struts  205  to  208  and causes then to descend at the same time. As with the device  30  in  FIG. 1 , the downward motion of the side plates  203  and  204  first places a depressive force on the patient&#39;s chest  212 . It also causes the levers  215  and  216  to rotate about their pivot point  217  and the levers  219  and  220  to rotate about their pivot point  221  to raise the belt ends  225  and  226  and circumferentially constrict the chest  212  in exactly the same fashion as the device  30  in  FIGS. 1 to 7 . The only difference in the two devices  30  and  201  in their mechanical operation is that the operator places his or her hands at most any generally opposed points on the wheel  202  in  FIGS. 10 to 12  whereas the operator must grab the opposed handles  33  and  34  in  FIGS. 1 to 7 . This gives the device  201  an additional degree of flexibility not provided by the device  30 . 
     However, the CPR device  201  of  FIGS. 10 to 12  has numerous other features that enable it to perform its life-saving function in many different advantageous ways. Thus, as seen in  FIGS. 10 and 12 , the base  231  of the CPR device  201  includes the combined electrocardiogram (“EKG”) and defibrillation (“defib”) and possibly pressure sensitive pad  232 . Similarly, the belt  233  incorporates the EKG-defib pads  234  to  236 . The pads  232  and  234  to  236  have the usual functions indicated by the terms EKG and defibrillation. These pads couple to the wire  237  which may serve as an antenna or a quick connect and disconnect device through the plug  238 . The wire may embed within the belt  233 . The plug may allow for connection to an external computer or other device for monitoring the patient. It may also allow connection to a telephone or other device for transmission of its signals to other stations, and it may also indicate its own location. 
     Additionally, the CPR equipment  201  includes the electronic pack indicated generally at  243  that provides a variety of functions to aid in the task of saving a patient&#39;s life. First it may have the EKG display  244  which connects, in turn, to the pads  232  and  234  to  236 . This provides a skilled operator with an indication of the patient&#39;s condition and progress. Next to the EKG display  244 , the pack  243  may include the visual indicator  245  which tells the operator when to push down and complete a stroke. Most conveniently, the indicator  245  may take the form of a light that shines when it wishes for a CPR stroke. 
     The pack  243  also incorporates the display gauge  251  that indicates the pressure exerted by the operator&#39;s downward stroke. This informs the operator if he or she is providing adequate force to achieve effective CPR. The gauge receives its input from a pressure pad that may have a colocation with or form part of the EKG-defib pad  232 . 
     The speaker  252  may provide an audible signal to indicate that a compression should occur. It could also provide verbal directions to facilitate the attachment and use of the CPR device  201  itself. Sitting next to the speaker  252 , the on-off switch  253  controls the overall operation of the pack  243 . As seen best in  FIG. 11 , the pack  243  also includes the computer  261  that controls the pack&#39;s other functions. It may also incorporate security features such as passwords or biometric measurements to identify the attendant and limit access to the operation of the pack  243 . The computer  261  may also record and store information concerning the actuation of the equipment and the signals generated by it. In particular, the computer  261  can monitor the overall operation of the device and determine the most advantageous times to compress, ventilate or defibrillate the patient based in part on signals received from the pads  232  and  234  to  236 . It can then operate the components that achieve these functions. The battery  262  then provides the power for the other components discussed above. 
     Additionally or separately, the pack  243  nay include the fluid piston or electrical motor  267  that can assist in the operation of the device  201  or operate it itself. It can receive its fluid or electrical power though the coupling  268  that connects to the electrical or fluid cable  269 , as appropriate. The cable  269  then passes to the control assembly  270  which includes the gauge  273  which indicates the amount of pressure or electricity remaining in the tank or battery  274 . The rotary switch  275  may turn the motor on and off and allow the selection of the frequency of the application of the CPR cycles. The selector switch  276  then permits a determination of the force to be applied to the patient. This may also work with feedback along the multichannel cable  269  to maintain the pressure at the preselected value. 
     Alternately, the tank  274  may simply hold oxygen that will travel along the cable  269  to the device  201  for delivery to the patient. The controller  270  in this instance includes the on-off and magnitude rotary switch  275 , the pressure controller  276 , and the gauge  273 . 
       FIGS. 10 and 12  also show the detachable guide  281  that can releasably attach to the belt ends  225  and  226  of the belt  234 . The guide  281  and each of the ends  225  and  226  may include a mechanism such as hooks and loops to attach them together. The guide  281  provides some stiffness to allow the belt ends  225  and  226  to be forced under the patient and fed into the device  201 . It also provides some additional length for tightening the belt  233  around the patient&#39;s chest  212  should that prove necessary. 
       FIGS. 10 to 13  also show the clip generally at  285  for holding the belt  233  onto the bar  286 . The Kelly et al. patents and applications suggest hooks and loops for this purpose. This type of connecting device may well perform with complete satisfaction for the anticipated uses of a CPR mechanism. However, the hooks and loops attachment may not prove acceptable under all conditions. Thus, it loses its effectiveness when wet or dirty. Moreover, it can wear out after extensive use. 
     The clip  285  avoids these limitations. It includes the curved metal latch  289  which can rotate about its journaled connection  290  to the levers  216  and  220 . Inserting the belt into the clip first involves lifting the latch  289  by turning it in the counterclockwise direction in  FIG. 13  and feeding the belt end  226  (possibly with the guide  281  attached) between it and the bar  286 . Locking the belt  233  in place then proceeds by pressing the latch extension  291  in the clockwise direction in that figure. This forces the latch knob  292  to press against the belt  233  and hold it against the bar  286 . Any force that would tend to pull the belt  233  out of the device actually causes the latch knob  292  to push the belt  233  harder against the bar  286  and, by squeezing the belt more tightly, keep it in place for the CPR. Releasing the belt  233  from the latch  285  merely involves lifting the latch end  291  with the fingers and moving it in the counterclockwise direction. This opens the space between the knob  292  and the bar  286  and permits the facile removal of the belt end  226 . 
       FIGS. 14 to 16  show the CPR device generally at  301  built on the principles shown in  FIG. 6  of the Kelly et al. patents and applications. The base  302  sits upon the patient&#39;s chest, and the belt  303  circumnavigates the patient&#39;s thorax in the usual fashion. The belt end  307  passes under the rod  308  affixed to the side  309  by the tabs  310 . Similarly, the other belt end  311  passes under a rod held by tabs (all not seen in the figure) to the side  312 . The belt ends  307  and  311  pass onto the stage  315  (in  FIGS. 15 and 16 ) where the cap  316  holds them securely in place with the belt snug around the patient&#39;s chest. 
     The stage  315  and the cap  316  attach to the two rack gears  321  and  322  which have the teeth  323  on both sides. The rack gears  321  and  322  and thus the stage  315  and the cap  316  remain free to move vertically relative to the base  302  and the sides  311  and  312 . Furthermore, The platform  315  attaches to the post  325  which can also move vertically in the housing  326 , which is also attached to the base  302 . The insertion of the post  325  into the housing  326  guides the vertical motion of the stage  315 . As the stage  315  moves upward, it also pulls the belt ends  307  and  311  in the same direction. This pulls the belt ends  307  and  311  through the rods (one of which appears in  FIG. 14  and bears the number  308 ) and tightens the belt  303  around the patient&#39;s chest for CPR. 
     However, the vertical motion of the stage  315  and thus the tightening of the belt  303  fall ultimately under the control of the handles  331  and  332 . The left handle (in the figures)  331  attaches to the two arms  335  and  336  which, in turn, connect to the two gear segments  337  and  338 , respectively. 
     Pushing down on the handle  331  will cause the arms  335  and  336  and the gear segments  337  and  338  to rotate in the counterclockwise direction (in the figures) around the rod  341  attached to the sides  309  and  312  by the bolts  343  and  344 , respectively. As the handle  331  and thus the gear segments  337  and  338  rotate in the counterclockwise direction, the teeth on the segments  337  engage the teeth  323  on the left side of the rack gears  321  and  322  causing them to move upwards. This takes the stage  315  and the belt ends  307  and  311  in the same direction which serves to tighten the belt  303  around the patient&#39;s chest for CPR. 
     Similarly, the handle  352  connects to the two arms  353  and  354 . Pushing down on the handle  352  causes it to rotate in the clockwise direction and move its two gear segments (only the one of which labeled  357  appears in the figures) in the same direction. These, in turn, engage the right side of the rack gears  321  and  322  causing them to move upwards. This helps lift the state  315  and tighten the belt  303  around the patient&#39;s chest. 
     Thus, pushing down on the handles  331  and  352  accomplishes two tasks. First, it applies a downward force directly from the base  302  onto the patient&#39;s chest to depress it. Second, it tightens the belt  303  around the patient&#39;s chest to compress it. Both of these actions contribute to the desired CPR. 
     The spring  361  sits around the bar  341  and biases the handle  331  in the clockwise direction. If the operator releases the handle  331  after a CPR cycle, the spring  361  will move it back to the upright position seen in the figures. There it will wait for the next cycle. 
       FIG. 17  shows a CPR device generally at  401  identical to the unit  301  of  FIGS. 14 to 16 . However, it also includes the large suction cup  402  that sits on the patient&#39;s chest. Upon the completion of a CPR stroke (as discussed in reference to  FIGS. 14 to 16 ), the operator can pull upwards on the handles  303  and  304 . This will cause the suction cup  402  upward and pull the patient&#39;s chest in the same direction. This chest expansion assists in the blood flow around the heart and also facilitates the patient&#39;s obtaining air for breathing. Instead of the suction cup, the device  410  may have an adhesive on the bottom of its base to accomplish the same objectives.