Abstract
BACKGROUND: Cerebral oxygen delivery (cDO(2)) is low during chest compressions (CC). We hypothesized that gas exchange and cDO(2) are better with continuous CC with high frequency percussive ventilation (CCC + HFPV) compared to conventional 3:1 compressions-to-ventilation (C:V) resuscitation during neonatal resuscitation in preterm lambs with cardiac arrest induced by umbilical cord compression. METHODS: Fourteen lambs in cardiac arrest were randomized to 3:1 C:V resuscitation (90CC + 30 breaths/min) per the Neonatal Resuscitation Program guidelines or CCC + HFPV (120CC + HFPV continuously). Intravenous epinephrine was given every 3 min until return of spontaneous circulation (ROSC). RESULTS: There was no difference in the incidence and time to ROSC between both groups. Median (IQR) PaCO(2) was significantly lower with CCC + HFPV during CC, at ROSC and 15 min post-ROSC-[104 (99-112), 83 (77-99), and 43 (40-64)], respectively compared to 3:1 C:V-[149 (139-167), 153 (143-168), and 153 (138-178) mmHg. PaO(2) and cDO(2) were higher with CCC + HFPV during CC and at ROSC. PaO(2) was similar 15 min post-ROSC with a lower FiO(2) in the CCC + HFPV group 0.4 (0.4-0.5) vs. 1 (0.6-1). CONCLUSION: In preterm lambs with perinatal cardiac-arrest, continuous chest compressions with HFPV does not improve ROSC but enhances gas exchange and increases cerebral oxygen delivery compared to 3:1 C:V during neonatal resuscitation. IMPACT STATEMENT: Ventilation is the most important intervention in newborn resuscitation. Currently recommended 3:1 compression-to-ventilation ratio is associated with hypercarbia and poor oxygen delivery to the brain. Providing uninterrupted continuous chest compressions during high frequency percussive ventilation is feasible in a lamb model of perinatal cardiac arrest, and demonstrates improved gas exchange and oxygen delivery to the brain. This is the first study in premature lambs evaluating high frequency percussive ventilation with asynchronous chest compressions and lays the groundwork for future clinical studies to optimize gas exchange and hemodynamics during chest compressions in newborns.