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

Objective: 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 hemo-dynamic recovery in severely asphyxiated piglets is unknown. Aim: To examine if different lengths of SI will improve ROSC and hemodynamic recovery in severely asphyxiated piglets. Intervention and measurements: 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. Main results: 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. Conclusions: 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.