Cardiopulmonary resuscitation with a hydraulic-pneumatic band

Improved blood flow during cardiopulmonary resuscitation (CPR) has been sho wn to enhance survival from cardiac arrest, Chest compression with a circum ferential pneumatic vest enhances blood flow, but the size, weight, and ene rgy consumption of the inflation system limit its portability and, thereby, have made clinical studies difficult. The purpose of this investigation wa s to study an improved circumferential chest compression device that uses a constricting band that is pneumatically actuated. The constricting band ap plies its force to a hydraulic cushion that contacts the anterior and later al aspects of the chest. The hydraulic cushion transfers the circumferentia l constriction to inward force. CPR was performed on subjects 5 mins after induction of ventricular fibrillation, with the hydraulic-pneumatic band sy stem (HB-CPR), with a pneumatic vest system (PV-CPR), and with standard man ual CPR (S-CPR), each done for 2 mins in randomized order. Aortic and right atrial pressures were measured with micromanometers. Coronary perfusion pr essure was calculated as the mean difference between the aortic and right a trial pressures during the release phase of chest compression. Aortic press ure and coronary perfusion pressure with HB-CPR and PV-CPR were improved ov er S-CPR, and HB-CPR produced comparable pressures to those of PV-CPR, The system for performing HB-CPR, however, was substantially lighter (10 vs. 50 kg) and consumed less energy (300 vs. 1000 watts) than that far PV-CPR, Th us, HB-CPR appears to produce a similar improvement in hemodynamics over S- CPR as PV-CPR but may be more portable than PV-CPR, Therefore, HS-CPR may a llow larger scale testing of circumferential chest compression approaches.