title: A preliminary study of cardiopulmonary resuscitation by circumferential compression of the chest with use of a pneumatic vest.
abstract: BACKGROUND
  More than 300,000 people die each year of cardiac arrest. Studies have shown that raising vascular pressures during cardiopulmonary resuscitation (CPR) can improve survival and that vascular pressures can be raised by increasing intrathoracic pressure.
  
  
  METHODS
  To produce periodic increases in intrathoracic pressure, we developed a pneumatically cycled circumferential thoracic vest system and compared the results of the use of this system in CPR (vest CPR) with those of manual CPR. In phase 1 of the study, aortic and right-atrial pressures were 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 initial manual CPR had been unsuccessful. Vest CPR was also carried out on 14 other patients in whom pressure measurements were not made. In phase 2 of the study, short-term survival was assessed in 34 additional patients randomly assigned to undergo vest CPR (17 patients) or continued 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 < 0.001) 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 the 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 leave the hospital.
  
  
  CONCLUSIONS
  In this preliminary study, vest CPR, despite its late application, successfully increased aortic pressure and coronary perfusion pressure, and there was an insignificant trend toward a greater likelihood of the return of spontaneous circulation with vest CPR than with continued manual CPR. The effect of vest CPR on survival, however, is currently unknown and will require further study.
authors.affiliation: Peter Belfer Cardiac Mechanics Laboratory, Department of Medicine, Johns Hopkins Hospital, Baltimore, MD 21205.
authors.forename: H R
authors.initials: HR
authors.lastname: Halperin
authors.forename: J E
authors.initials: JE
authors.lastname: Tsitlik
authors.forename: M
authors.initials: M
authors.lastname: Gelfand
authors.forename: M L
authors.initials: ML
authors.lastname: Weisfeldt
authors.forename: K G
authors.initials: KG
authors.lastname: Gruben
authors.forename: H R
authors.initials: HR
authors.lastname: Levin
authors.forename: B K
authors.initials: BK
authors.lastname: Rayburn
authors.forename: N C
authors.initials: NC
authors.lastname: Chandra
authors.forename: C J
authors.initials: CJ
authors.lastname: Scott
authors.forename: B J
authors.initials: BJ
authors.lastname: Kreps
mesh_terms: D001011:Aorta / Q000503:physiopathology; D016280:Atrial Function, Right; D001775:Blood Circulation; D001794:Blood Pressure; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D005260:Female; D005676:Gravity Suits; D006323:Heart Arrest / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged