Asynchronous ventilation at 120 compared with 90 or 100 compressions per minute improves haemodynamic recovery in asphyxiated newborn piglets

Abstract

Objective: To determine whether different chest compression (CC) rates during continuous CC with asynchronous ventilations (CCaV) reduce time to return of spontaneous circulation (ROSC) and improved haemodynamic recovery in piglets aged 24-72 hours with asphyxia-induced asystole.

Methods: Thirty piglets (aged 24-72 hours) were anaesthetised, intubated, instrumented and exposed to 30 min normocapnic hypoxia followed by asphyxia. Piglets were randomised into four groups: CCaV with CC rate of 90 (CCaV+90, n=8), 100 (CCaV+100, n=8) or 120 compressions per minute (CCaV+120, n=8), and a sham-operated group (n=6). Cardiac function, carotid blood flow, cerebral and renal oxygenation and respiratory parameters were continuously recorded. Cerebral cortical tissue was harvested and assayed for inflammatory and injury markers.

Results: All three intervention groups had a similar number of piglets achieving ROSC (6/8, 5/8 and 5/8 for CCaV+120, CCaV+100 and CCaV+90, respectively) and mean ROSC time (120, 90 and 90 s for CCaV+120, CCaV+100 and CCaV+90, respectively). The haemodynamic recovery (indicated by carotid flow, cerebral and renal perfusion) was similar between CCaV+120 and sham by the end of experiment. In comparison, CCaV+90 and CCaV+100 had significantly reduced haemodynamic recovery compared with sham operated (p≤0.05). Inflammatory (interleukin [IL]-6 and IL-1β) and injury markers (lactate) were significantly higher in the frontoparietal cortex of CCaV+90 and CCaV+100 compared with sham, whereas brain injury markers were similar between CCaV+120 and sham.

Conclusions: Although there was no difference between the groups in achieving ROSC, the haemodynamic recovery of CCaV+120 was significantly improved compared with CCaV+90 and CCaV+100, which were also associated with higher cerebral inflammatory and brain injury markers.

Keywords: chest compressions; infants; neonatal resuscitation; newborn.