Effects of different durations of sustained inflation during cardiopulmonary resuscitation on return of spontaneous circulation and hemodynamic recovery in severely asphyxiated piglets.

Abstract

We previously demonstrated that sustained inflation (SI) during chest compression (CC) significantly reduces time to return of spontaneous circulation (ROSC) when compared to 3:1 compression:ventilation (C:V) ratio during neonatal resuscitation. However, the optimal length of SI during CC to improve ROSC and hemodynamic recovery in severely asphyxiated piglets is unknown. To examine if different lengths of SI will improve ROSC and hemodynamic recovery in severely asphyxiated piglets. Thirty newborn piglets (1-3 days) were anesthetized, intubated, instrumented and exposed to 30-min normocapnic hypoxia followed by asphyxia. Piglets were randomized into four groups: 3:1 C:V (n = 8), CC with an SI duration of either 20 s (CC+SI 20) (n = 8) or 60 s (CC+SI 60) (n = 8), and a sham group (n = 6). Cardiac function, carotid blood flow, cerebral and renal oxygenation as well as respiratory parameters were continuously recorded throughout the experiment. When compared with 3:1 group, both CC+SI 20 and CC+SI 60 groups had significantly shorter ROSC time (p = 0.002). All three intervention groups had similar hemodynamic recovery by the end of 4 h observation period. There was no difference in lung injury markers among all experimental groups. However, when compared to the sham group, the concentrations of IL-6 (thalamus) and IL-6 + IL-8 (frontoparietal cortex) of the 3:1 C:V group were significantly higher, respectively. Even though relatively less animals achieved ROSC, CC during SI significantly improved ROSC time compared to 3:1 C:V in asphyxiated newborn piglets. However, there was no difference in ROSC characteristics and hemodynamic recovery between two CC+SI groups.