Interposed abdominal compression (IAC)-CPR includes all steps of standard external CPR with the addition of manual mid-abdominal compressions in counterpoint to the rhythm of chest compressions. IAC-CPR can increase blood flow during CPR about two fold compared to standard CPR without IAC, as shown by 6 of 6 studies in computer models and 19 of 20 studies in various animal models. The addition of IAC has clinical benefit in humans, as indicated in 10 of 12 small to medium sized clinical studies. The technique increases the frequency of immediate return of spontaneous circulation for in-hospital resuscitations from roughly 25% to 50%. Improved survival to discharge is also likely on the basis of two small in-hospital trials. Possible harm from abdominal compression is minimal on the basis of 426 humans, 151, dogs and 14 pigs that received IAC in published reports. The complexity of performing IAC is similar to that of opening the airway and is less than that of other basic life support maneuvers. The aggregate evidence suggests that IAC-CPR is a safe and effective means to increase organ perfusion and survival, when performed by professionally trained responders in a hospital and when initiated early in the resuscitation protocol. Cost and logistical considerations discourage use of IAC-CPR outside of hospitals.