Comparison of Different Compression to Ventilation Ratios (2: 1, 3: 1, and 4: 1) during Cardiopulmonary Resuscitation in a Porcine Model of Neonatal Asphyxia

BACKGROUND:High-quality chest compression is essential during neonatal cardiopulmonary resuscitation (CPR). However, the optimal compression to ventilation ratio (C:V) that should be used during neonatal CPR to optimize coronary and cerebral perfusion while providing adequate ventilation remains unknown. OBJECTIVE:We hypothesized that different C:V ratios (e.g., 2: 1 or 4: 1) will reduce the time to return of spontaneous circulation (ROSC) in severely asphyxiated piglets. METHODS:Thirty-one newborn piglets (1-4 days old) were anesthetized, intubated, instrumented, and exposed to 50-min normocapnic hypoxia followed by asphyxia. Piglets were randomized into 4 groups: 2: 1 (n = 8), 3: 1 (n = 8), 4: 1 (n = 8) C:V ratio, or a sham group (n = 7). Cardiac function, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded throughout the experiment. RESULTS:Thirty-one piglets were included in the study, and there was no difference in the duration of asphyxia or the degree of asphyxiation (as indicated by pH, PaCO2, and lactate) among the different groups. The median (IQR) time to ROSC was similar between the groups with 127 (82-210), 96 (88-126), and 119 (83-256) s in the 2: 1, 3: 1, and 4: 1 C:V ratio groups, respectively (p = 0.67 between groups). Similarly, there was no difference in 100% oxygen requirement or epinephrine administration between the experimental groups. CONCLUSIONS:Different C:V ratios resulted in similar ROSC, mortality, oxygen, and epinephrine administration during resuscitation in a porcine model of neonatal asphyxia.