Evidence suggests that any interruptions, including those of rescue breaths, during cardiopulmonary resuscitation (CPR) have significant, detrimental effects on survival. The 2010 International Liaison Committee on Resuscitation guidelines strongly emphasized on the importance of minimizing interruptions during chest compressions. However, those guidelines also stress the need for ventilations in the case of prolonged cardiac arrest (CA), and it is not at present clear at which point of CA the necessity of providing ventilations overcomes the hemodynamic compromise caused by chest compressions' interruption.

Ventricular fibrillation was electrically induced in 20 piglets (19 ± 2 kg) and left untreated for 8 minutes. Animals were randomized to receive 2 minutes of either chest compression-only CPR (group CC) or standard 30:2 compressions/ventilations CPR (group S) before defibrillation. Resuscitated animals were monitored under anesthesia for 4 hours and then were awakened and placed in a maintenance facility for 24 hours.

There was no significant difference among groups for both return of spontaneous circulation and 1-hour survival. There was a significant difference in 24-hour survival (group CC, 7/10 vs group S, 2/10; P = .025). Blood lactate levels were significantly lower in group CC compared with group S in both 1 (P = .019) and 4 hours (P = .034) after return of spontaneous circulation. Furthermore, group CC animals exhibited significantly higher mean Neurologic Alertness Score (58 ± 42.4 vs 8 ± 16.9) (P < .05).

In this swine CA model, where defibrillation was first attempted at 10 minutes of untreated ventricular fibrillation, uninterrupted chest compressions resulted in significantly higher survival rates and higher 24-hour neurologic scores, compared with standard 30:2 CPR.