CPR-induced trauma: Comparison of three manual methods in an experimental model

Cardiopulmonary resuscitation (CPR) often results in traumatic injury to the patient. Differences in CPR-induced trauma among various forms of manual, external CPR, however, are unknown. We compared CPR-induced trauma among manual standard (STD) CPR at 60 compressions per minute; high-impulse compression (HIC) CPR at 120 compressions per minute; and interposed abdominal compression (IAC) CPR at 60 compressions per minute. A large (24 ± 3 kg) mongrel canine model was used. Ten animals were assigned to each type of CPR. Each received 17 minutes of CPR, applied to produce the best possible coronary perfusion pressure without obviously damaging the dog. Defibrillation was attempted at 20 minutes. Necropsy was performed at the time of death or after sacrifice at 24 hours. Careful postmortem examination of the thorax, lungs, heart, abdomen, and great vessels was performed. A semiquantitative trauma score of 0 to 5 was assigned to each area with a possible maximal score of 25. There was no difference in trauma scores among STD (6.4 ± 1.5), HIC (9.4 ± 1.4), and IAC (8.1 ± 1.3) methods. No significant correlation was found between the method of CPR and the different types of trauma. Specifically, IAC did not produce an increase in liver lacerations nor did HIC produce a significant increase in thoracic or pulmonary injuries. Six of 20 initially resuscitated animals expired during the 24-hour follow-up period due to CPR-induced injuries. Four of these six had extensive pulmonary trauma, including pulmonary hemorrhage or edema. Liver lacerations were the second most lethal injury. We conclude that external CPR commonly produces trauma, including serious injury in more than 25% of all recipients. There were no statistical differences in amount or type of trauma produced among STD, HIC, or IAC CPR. The most serious injuries produced were pulmonary hemorrhage and hepatic lacerations.