A PRELIMINARY-STUDY OF CARDIOPULMONARY-RESUSCITATION BY CIRCUMFERENTIAL COMPRESSION OF THE CHEST WITH USE OF A PNEUMATIC VEST

Background. More than 300,000 people die each year of cardiac arrest. Studies have shown that raising vascular pressures during cardiopulmon ary resuscitation (CPR) can improve survival and that vascular pressur es can be raised by increasing intrathoracic pressure. Methods. To pro duce periodic increases in intrathoracic pressure, we developed a pneu matically cycled circumferential thoracic vest system and compared the results of the use of this system in CPR (vest CPR) with those of man ual CPR. In phase 1 of the study, aortic and right-atrial pressures we re measured during both vest CPR (60 inflations per minute) and manual CPR in 15 patients in whom a mean (+/-SD) of 42+/-16 minutes of initi al manual CPR had been unsuccessful. Vest CPR was also carried out on 14 other patients in whom pressure measurements were not made. In phas e 2 of the study, short-term survival was assessed in 34 additional pa tients randomly assigned to undergo vest CPR (17 patients) or continue d manual CPR (17 patients) after initial manual CPR (duration, 11+/-4 minutes) had been unsuccessful. Results. In phase 1 of the study, vest CPR increased the peak aortic pressure from 78+/-26 mm Hg to 138+/-28 mm Hg (P<0.0010 and the coronary perfusion pressure from 15+/-8 mm Hg to 23-11 mm Hg (P<0.003). Despite prolonged unsuccessful manual CPR, spontaneous circulation returned with vest CPR in 4 of the 29 patients . In phase 2 of the study, spontaneous circulation returned in 8 of th e 17 patients who underwent vest CPR as compared with only 3 of the 17 patients who received continued manual CPR (P = 0.14). More patients in the vest-CPR group than in the manual-CPR group were alive 6 hours after attempted resuscitation (6 of 17 vs. 1 of 17) and 24 hours after attempted resuscitation (3 of 17 vs. 1 of 17), but none survived to l eave the hospital. Conclusions. In this preliminary study, vest CPR, d espite its late application, successfully increased aortic pressure an d coronary perfusion pressure, and there was an insignificant trend to ward a greater likelihood of the return of spontaneous circulation wit h vest CPR than with continued manual CPR. The effect of vest CPR on s urvival, however, is currently unknown and will require further study.