Improved oxygen delivery during cardiopulmonary resuscitation with interposed abdominal compressions

The ability of a new modification of cardiopulmonary resuscitation (CPR) to deliver oxygen to tissues was evaluated. The method utilizes standard CPR techniques with the addition of manual abdominal compressions (congruent to 100 mm Hg) interposed between chest compressions, and is termed interposed abdominal compression-CPR (IAC-CPR). Oxygen delivery was measured by a spirometer in a closed circuit designed to permit positive-pressure ventilation synchronized with mechanical chest compression. Ventricular fibrillation was induced electrically in 10 anesthetized dogs. In each dog, trials of IAC-CPR and standard CPR were alternated every five minutes during a 30-minute period. Arterial and central venous blood pressures, oxygen consumption, and Fick cardiac output were monitored. The addition of interposed abdominal compression significantly (P less than .01) increased each of these hemodynamic indicators. Oxygen delivery increased from 4.12 +/- 0.39 ml O2/kg/min during standard CPR to 6.37 +/- 0.35 ml O2/kg/min during IAC-CPR. Arterial systolic blood pressure increased from 67 +/- 5 mm Hg to 90 +/- 5 mm Hg, while diastolic arterial blood pressure rose from 15 +/- 2 mm Hg to 33 +/- 3 mm Hg. Cardiac output increased from 19.9 +/- 2.6 ml/min/kg to 37.5 +/- 2.7 ml/min/kg.