Interposed abdominal compression-CPR in human subjects

Standard cardiopulmonary resuscitation (CPR) has been thought to produce approximately 30% of the usual resting cardiac output. Further increase of blood flow to vital organs may increase chances of resuscitation and decrease likelihood of permanent, residual central nervous system or cardiac damage. Various methods have been promoted, most requiring equipment not available to bystanders and time to initiate once advanced cardiac life support (ACLS) providers have necessary equipment at hand. Interposed abdominal compression-CPR (IAC-CPR), application of manual abdominal pressure during the release phase of chest compression in otherwise standard CPR, has been demonstrated in dogs to increase diastolic blood pressure by 100% and cardiac output by 75%. We measured systolic and mean arterial pressure (MAP) in a group of six cardiac arrest patients after resuscitation was deemed unsuccessful by the physician directing CPR. We alternated periods of CPR versus IAC-CPR measuring femoral and radial or brachial pressures in six subjects, and found a 50% increase in MAP (from 26 to 39 mm Hg). Central venous pressures (CVP) were measured in one subject and, using MAP minus mean CVP to determine mean perfusion pressure, we found a 37% increase (from 19 mm Hg to 26 mm Hg). We propose that IAC-CPR may be a significant improvement in basic CPR if these studies are reproducible in resuscitable patients.