Interposed abdominal compression-CPR: its effects on parameters of coronary perfusion in human subjects.

Recent literature has emphasized the relationship between coronary perfusion during CPR and the success of resuscitation from prolonged arrest. In this study, aortic and right atrial pressures were monitored simultaneously during modifications of CPR. Three parameters associated with survival or coronary blood flow during CPR were measured: diastolic arterial pressure (DAP), diastolic arteriovenous difference (DAVD), and mean AV difference (MAVD). Standard advanced cardiac life support protocol was used although vasopressors were given by continuous infusion. In a series of two-minute trials, standard CPR, interposed abdominal compression (IAC) CPR, high-compression force (HCF) IAC-CPR, and HCF standard CPR were performed, with each patient serving as his own control. The DAP increased from 25 mm Hg during standard CPR to 43 during IAC CPR (P less than .001) and 50 during HC-IAC-CPR (P less than .001). The MAVD increased from 4 to 8 mm Hg during HCF-IAC-CPR (P less than .05). IAC-CPR had inconsistent effects on the DAVD. Three patients had a return of spontaneous circulation during the modifications of CPR after a mean of 43 minutes of asystole with standard CPR. In the seven autopsied patients, no significant abdominal injury was found. All forms of CPR studies produced DAVD in the majority of patients well below the minimum DAVD needed for resuscitation in animal models of prolonged arrest. Although the interposed abdominal compression seems to offer some advantages over standard CPR, these hemodynamic data suggest that it would be unlikely to improve survival rates appreciably.