We have previously reported, on the basis of experimental studies, that interruptions of CPR as little as 10 seconds adversely affect the outcomes of CPR. We therefore investigated interruptions of only 5 seconds for delivering ventilation, which corresponds to the current AHA algorithm in which of 30 compressions followed by 2 ventilations are mandated. We hypothesized that even 5 seconds interruption significantly reduces CPP and with significant delay prior to restoring pre-interruption levels. Ventricular fibrillation (VF) was induced and untreated for 15 minutes in 33 male domestic pigs weighting 40±3 Kg. Chest compressions delivered with the aid of mechanical compressor (Thumper, 1000, MI Instruments) with a rate of 100/min. Ventilations were administrated with a compression / ventilation ratio of 30:2 such that 2 ventilations were delivered over a 5 seconds interval. CPP was continuously measured as the difference between comparison diastolic and simultaneous left atrial pressure. CPP significantly decreased during interruptions for ventilation from 20.5±12.8 mmHg to 9.8±6.7 mmHg(
P
<0.001). After chest compressions were restarted, the CPP increased to 12.5±7.6 mmHg after first compression(
P
<0.001). A total of 12±7 compressions over a mean interval of 7.2±4.3 seconds was required prior to restoration of CPP to levels corresponding to those that preceded the interruption. As little as the five seconds of interruption in chest compression currently mandated for 30 to 2 ventilations during CPR significantly reduced CPP and delayed restoration of CPP to its pre-interruption level.
Blood Pressure– and Coronary Perfusion Pressure–Targeted Cardiopulmonary Resuscitation Improves 24-Hour Survival From Ventricular Fibrillation Cardiac Arrest
