IE41992B1 - Method and apparatus for administering cardiopulmonary resuscitation - Google Patents

Abstract

1526021 Aid for cardiopulmonary resuscitation R M HARRIGAN 9 Jan 1976 [17 Jan 1975 29 Aug 1975] 00818/76 Heading A5R An aid for external cardiopulmonary resuscitation consists of an inflatable cushion or a foam cushion 12 within an inflatable cushion 11 and which is in use placed on the patient's chest and measures by air gauge 17 the pressure applied to the chest, the gauge being calibrated in pounds although it measures the pressure in pounds per square inch in the cushion. An inflation valve 13 is provided, together with an instruction sheet 16, an adhesive layer 14 covered by a protective sheet 15, and a timer 17' to indicate the interval between successive applications of pressure. As an alternative to the timer the indicator may have a relax time equal to half the time between applications.

Description

This invention relates to a method of and apparatus for administering cardiopulmonary resuscitation.

When the heart is stopped as a result of injury, poisoning, electric shock, heart attack or other causes, circulation sufficient to maintain life may be maintained by a rhythmic application of the correct amount of pressure to the chest.

In adult males, for example, the correct pressure is approximately ninety pounds. If too little pressure is applied, the circulation created, { if any, will not be sufficient to prevent brain damage or even death. On the 10 other hand, if the pressure applied is too great, broken ribs, punctured lungs and other damage may result. Further, application of pressure on too small an area of the chest can more readily result in broken ribs and other damage, for example, if the knuckles of the rescuer's hand are pressing on the victim's ribs. Also, if the pressure is not applied evenly but applied in quick jabs, the likelihood of injury is increased, and if the pressure is not applied rhythmically and with proper timing, satisfactory results may not be obtained.

According to one aspect of the .invention apparatus for use in administering external cardiopulmonary resuscitation comprises an indicator for indicating the pressure or force applied by the user to the patient's chest, and a cushion which, in use, is placed on the patient’s chest, wherein the indicator - 2 41993 is connected to the cushion and supported by a rigid pipe and is sensitive to the pressure within the cushion and thereby indicates the pressure or force applied to the patient's chest.

According to another aspect of the invention, a method of administering cardiopulmonary resuscitation to a patient in which apparatus comprising a cushion and a pressure indicator sensitive to the pressure within the cushion is placed on the patient's chest, a predetermined force as measured by the indicator is applied to the patient's chest via the cushion, the force is removed, and the application and removal of force is repeated.

Preferably, the cushion is inflatable.

One embodiment of the invention includes an inflatable cushion of heavy vinyl or other suitable material approximately three inches square (i.e. in the region of nine square inches) and two inches high (when inflated) having a pressure indicator such as a pressure gauge associated therewith. The structure is inflated by mouth through a suitable inflation valve such as are found on air mattresses. The gauge may be calibrated to indicate the pressure applied to a victim by placing the inflatable structure on a spring weight scale and applying various pressures (especially in the range required for external cardiac resuscitation) on the structure and recording these pressures from the spring weight scale onto the face of the pressure gauge indicator face. In experiments it has been found that a pressure of eight pounds per square inch on the gauge is representative of a downward force on the inflatable structure of ninety pounds.

In use, the above described external cardiac resuscitation apparatus is inflated by mouth and placed on a victim's chest over the lower sternum, and pressure is applied to the victim's chest through the apparatus. The user will observe the gauge each time he applies pressure (about once per second) to be sure that the proper pressure is attained. - 3 41992 In another embodimeht a timing device such as an easily readable stop watch may be attached to the apparatus to'enable the rescuer to maintain the proper rhythm. Any other suitable timing device can be used using audible and/or visual signals, as an example. Electronic or other timing means and even a compact metronome device could be used. For example, the rhythm should be one compression and relaxation per second (compression comprising one half second, relaxation one half second).

In another embodiment the timing means may be an integral part of the pressure gauge, for example, the pressure gauge may be designed so that an appropriate time interval, e.g. one half second, is required for the pressure indicator pointer to relax to zero. Ideally, this timing feature is adjustable to suit different circumstances.

The resiliency of the inflatable cushion is a valuable feature.

This resiliency tends to reduce the chances of damage or injury to the patient when administering cardiopulmonary resuscitation (CPR) by virtue of the fact that it provides for an even distribution of pressure. Further, it tends to absorb the harmful effect of improperly applied CPR, such as sharp jabs rather than even, regular compressions.

Further improvement to any of the previously described embodiments can be obtained by including a pressure sensitive adhesive surface, such as medical adhesive tape, on the bottom of the cushion. This adhesive would have a peel-off cover. Thus, the rescuer need only locate the proper position for the apparatus, peel off the cover and apply the apparatus to the victim's chest. Then, should the rescuer have to stop the CPR for an interval because of moving or transporting the victim or to apply the mouth-to-mouth resuscitation (one man rescue) the rescuer will not lose time in reapplying CPR because the apparatus will have remained in the proper position on the victim's chest. Further, the chance of causing damage by inadvertently applying pressure in the wrong place will be greatly reduced. - 4 41992 Any type of suitable pressure-sensing device coupled with a suitable pressure indicator may be employed. For example, an electrical transducer might be used to sense pressure in the inflatable cushion. The indicator may generate a visual and/or audible signal.

Particular embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which;Figure 1 is a perspective view of one embodiment of an external cardiopulmonary resuscitation apparatus according to the invention; Figure 2 shows a section of another embodiment of an apparatus according to the invention; Figure 3 is a view illustrating the application of CPR using the apparatus of this invention.

With reference now to the drawings, there is shown in Figure 1 an inflatable cushion of vinyl or other suitable material 1 with an inflatable valve 2, such as found in air mattresses and children's inflatable toys. The inflatable cushion is also provided with a pressure gauge 3 which measures the pressure inside the inflatable cushion. The pressure gauge 3 indicates the downward force exerted on the structure, which force is related to but not necessarily equal to the pressure inside the structure. Optional instructions may be printed at 4 on the top of the inflatable cushion of the external cardiac resuscitation apparatus. In addition, a timing means (not shown) may be used in conjunction with pressure gauge 3 to enable proper rhythmical application of CPR.

Figure 2 is a cross-sectional view of a similar embodiment with optional improvements. Inflatable vinyl cushion 11 is provided with a one way inflation valve and tube 13. Inflation valve 13 is not required if the apparatus is provided with its own sealed-in supply of air or other fluid. An optional, resilient, porous, foam rubber or porous foam plastics material pad 12 - 5 41992 may be located inside the inflatable or inflated vinyl cushion Π to permit continued use of the cushion even if it becomes punctured and unable to hold air. Optional adhesive layer 14 may be located on the bottom surface of the cushion covered by removable sheet 15. A flexible instruction sheet 16 showing detailed instructions for CPR is attached both to the cushion and to pressure gauge 17. Instructions 16 and the face of pressure gauge 17 may be provided with luminous lettering or other indicia for use when no light is available.

Pressure gauge 17 may be designed so that the pressure indicator needle requires one half second or some other predetermined time interval to relax back to zero to provide for a timing reference for the rescuer. Another optional feature may provide for this relaxation time interval to be adjustable. This timing feature is illustrated in Figure 2 by 17' and other timing means not specifically described herein may also be used. A pipe 18 supports the pressure gauge 17 and conducts thereto fluid pressure from the interior IT of cushion II, to pressure gauge 17 so that the force and pressure exerted by the rescuer on the cushion is registered on gauge 17.

The apparatus of the present invention may be inexpensive, portable, and compact and may also provide for a predetermined time interval for relaxation to zero of the pressure gauge whereby a timing reference is also provided for the 2q rescuer and whereby the correct rhythm can be followed in applying CPR. Studies have shown that up to 40% of persons trained in CPR forget the proper CPR technique three months after having been trained. This invention enables anyone to properly administer CPR, even those who are untrained or those who have forgotten their training.

Claims (14)

1. 25 CLAIMS

1. Apparatus for use in administering external cardiopulmonary resuscitation comprising an indicator for indicating the pressure or force applied by the user to the patient's chest and a cushion which, ih use, is placed on the patient's chest, wherein the indicator is connected to the cushion and supported by a pipe and is - 6 41992 sensitive to the pressure within the cushion and thereby indicates the pressure or force applied to the patient's chest.

2. Apparatus according to Claim 1 in which the area of that surface of the cushion which in use is placed against the patient's chest is of the order of nine square inches.

3. Apparatus according to Claim 1 or Claim 2 in which the cushion is inflatable and has an inlet enabling inflation thereof.

4. Apparatus according to any preceding claim including means to attach the apparatus to the chest of the patient.

5. Apparatus according to Claim 4 in which the said means to attach the apparatus is adhesive.

6. Apparatus according to Claim 5 including a removable sheet covering the adhesive,

7. Apparatus according to any preceding claim so constructed that the indicator takes a significant time to relax from a first reading to a second reading and can therefore be used as a timer to guide the user of the apparatus in applying pressure at a suitable frequency for resuscitation.

8. Apparatus according to Claim 7 in which the time interval for the indicator to relax is of the order of half a second.

9. Apparatus according to Claim 7 which can be adjusted to change the time taken for the indicator to relax.

10. Apparatus constructed and arranged substantially as described with reference to and as illustrated in Figure 1 of the accompanying drawings.

11. Apparatus constructed and arranged substantially as described with reference to and as illustrated in Figure 2 of the accompanying drawings.

12. A method for administering external cardiopulmonary resuscitation to a patient in which apparatus comprising a cushion and a pressure indicator sensitive to the pressure within the cushion is placed on the patient's chest via the cushion, the force is removed, and the application and removal of force is repeated. - 7 4199 2

13. A method according to Claim. 12 in which the period of removal of the force is displayed by the pressure indicator.

14. A method of administering cardiopulmonary resuscitation substantially as hereinbefore described and as illustrated in 1’igure 3 o£ the accompanying drawings