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

Abstract

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.

Comparison of two infant chest compression techniques during simulated newborn cardiopulmonary resuscitation performed by a single rescuer: A randomized, crossover multicenter trial

“…CC alone or with epinephrine in a delivery room is associated with poor prognosis [41]. However, there are some studies suggesting that different CC to ventilation ratios (2:1, 3:1, 4:1) result in similar return of spontaneous circulation and similar mortality during resuscitation in a porcine model of neonatal asphyxia [42].…”

Chest Compressions in the Delivery Room

“…Similarly, C:V ratios of 3:1 and 15:2 were compared using the same model 28 . Although the 15:2 C:V ratio provided a higher mean CC rate per minute (75 vs. 58 CC/min for 15:2 and 3:1, respectively), time to ROSC was similar between groups respectively (p=0.67 between groups), similar oxygen requirement, and epinephrine administration between the groups 29 . These studies suggest that different C:V ratios might not be the optimal approach for neonatal CPR.…”

A Porcine Model of Neonatal Hypoxia-Asphyxia to Study Resuscitation Techniques in Newborn Infants

“…Pasquin et al used the porcine model of neonatal hypoxia-asphyxia to examine different ratios of CC to ventilations; the standard 3:1 C:V technique was compared to a C:V ratio of 2:1 and 4:1 [37]. Time to ROSC, mortality, oxygen requirements, epinephrine administration, and hemodynamic recovery were similar between all groups, indicating no difference in the efficacy of various C:V ratios in asphyxialinduced cardiac arrest of neonatal piglets.…”