Continuous Chest Compressions with Asynchronous Ventilation in Asphyxiated Preterm Lambs with Asystole

Introduction: Gas exchange and perfusion are impaired during neonatal cardiopulmonary resuscitation. Continuous chest compressions with asynchronous ventilation (CCCaV) improve oxygenation and hemodynamics in term animal models compared to synchronized 3:1 compressions-to-ventilation (C:V). We hypothesized that CCCaV improves gas exchange and hemodynamics in preterm lambs. Methods: Sixteen extremely preterm (124–126 days gestation) lambs were asphyxiated to cardiac arrest by umbilical cord occlusion. Lambs were randomized to 3:1 C:V following the International Liaison Committee on Resuscitation algorithm or CCCaV (120 compressions and 40 asynchronized ventilations per minute). Epinephrine was given 3 min into resuscitation and repeated every 3 min until return of spontaneous circulation (ROSC). Results: All lambs achieved ROSC with no difference in time to ROSC. There was no difference in cerebral oxygen delivery (C-DO₂) in lambs resuscitated with CCCaV versus 3:1 C:V (0.05 [0.041] vs. 0.03 [0.031] mL O₂/kg/min, respectively) during chest compressions. CCCaV yielded higher arterial oxygen content (CaO₂ 2.07 [1.00] vs. 1.07 [0.69] mL O₂/dL), mean arterial pressure (14.2 [2.6] vs. 13.2 [2.3] mm Hg), and diastolic pressure (8.1 [1.8] vs. 7.1 [1.4] mm Hg) during chest compressions compared to 3:1 C:V. There was no difference in plasma reduced to oxidized glutathione [GSH/GSSG ratio] between groups at 10 min post-ROSC. Discussion: CCCaV in asystolic preterm lambs did not alter C-DO₂, frequency, or time to ROSC compared to standard 3:1 C:V resuscitation but increased CaO₂, mean, and diastolic arterial pressure compared to 3:1 C:V without increasing plasma oxidative stress markers.