Delayed high-quality CPR does not improve outcomes

Aim of studyThe quality of cardiopulmonary resuscitation (CPR) is an important factor in the outcome of cardiac arrest. Our objective was to compare outcomes following either immediate low-quality (LQ) CPR or delayed high-quality (HQ) CPR. We hypothesized that delayed HQ CPR will improve the outcomes of CPR in comparison to immediately performing LQ CPR.MethodsEighteen Sprague-Dawley rats were randomized into two groups: (1) Delayed HQ CPR (HQ group, n = 9). (2) Immediate LQ CPR (LQ group, n = 9). Ventricular fibrillation (VF) was induced and untreated for 8 mins. CPR was immediately performed in LQ group for 5 mins. Compression depth was set at 70% of the “optimal compression depth”. VF was untreated for an additional 5 mins in HQ group. HQ CPR was started together with ventilation (100% oxygen) and external hypothermia for 8 mins in both groups. The “optimal compression depth” was approximately 30% of the anteroposterior chest diameter. Epinephrine was administrated 3 mins prior to defibrillation attempt. Restoration of spontaneous circulation, postresuscitation myocardial function and survival time were monitored.ResultsAll animals in the LQ group and 7 of 9 animals in the HQ group were resuscitated. Myocardial function, including ejection fraction and cardiac output was better in the LQ group than in the HQ group (p < 0.05) and survival time was longer in the LQ group (p < 0.05).ConclusionThe outcomes after immediate LQ CPR, were better than those after delayed HQ CPR in this rat model of cardiac arrest and resuscitation.