A new device producing manual sternal compression with thoracic constraint for cardiopulmonary resuscitation

Summary: Objective: Blood flow during conventional cardiopulmonary resuscitation (CPR) is usually less than adequate to sustain vital organ perfusion. A new chest compression device (LifeBelt™) which compresses both the sternum and the lateral thoraces (compression and thoracic constraint) has been developed. The device is light weight, portable, manually powered and mechanically advantaged to minimize user fatigue. The purpose of this study was to evaluate the mechanism of blood flow with the device, determine the optimal compression force and compare the device to standard manual CPR in a swine arrest model. Methods: Following anesthesia and instrumentation, intravascular contrast injections were performed in four animals and the performance characteristics of the device were evaluated in eight animals. In a comparative outcome study, 42 anesthetized and instrumented swine were randomized to receive LifeBelt™ or manual CPR. Ventricular fibrillation (VF) was induced electrically and was untreated for 7.5min. After 7.5min, countershocks were administered and chest compressions initiated. Pulseless electrical activity (PEA) was observed after one to three shocks in all animals. CPR was continued until restoration of spontaneous circulation (ROSC) or for 10min after the first shock. If ROSC had not occurred within 5min of beginning CPR, 0.01mg/kg of epinephrine (adrenaline) was administered. During CPR, peak systolic aortic pressure (Ao), diastolic coronary perfusion pressure (CPP-diastolic aortic minus diastolic right pressure) and end-tidal CO2 were measured. Results: Angiographic studies demonstrated cardiac compression as the mechanism of blood flow. Optimal performance, determined by coronary perfusion pressure, was observed at a sternal force of 100–130lb (45–59kg). In the comparative trial, significant differences in the measured CPP were observed between LifeBelt™ and manual CPR both at 1min (15±8mmHg versus 10±6mmHg, p <0.05) and 5min (17±4mmHg versus 13±7mmHg, p <0.02) of chest compression. A greater (p <0.05) ETCO2, a marker of cardiac output and systemic perfusion, was observed with LifeBelt™ CPR (20±7mmHg) than with manual CPR (15±5mmHg) at 1min. Peak Ao pressures were not different between methods. With the device, 86% of animals were resuscitated compared to 76% in the manual group. Conclusions: Blood flow with the LifeBelt™ device is primarily the result of cardiac compression. At a sternal force of 100–130lb (45–59kg), the device produces greater CPP than well-performed manual CPR during resuscitation from prolonged VF. [Copyright &y& Elsevier]