Duration of Sustained Inflation During Sustained Inflation and Chest Compression in a Porcine Model of Asphyxia

Abstract

BACKGROUND Current resuscitation guidelines recommend 3:1 C:V ratio, however the most effective C:V ratio in newborns remains controversial. We recently demonstrate that combining chest compressions (CC) with a sustained inflation (SI) (=CC+SI) significantly improves return of spontaneous circulation (ROSC) in asphyxiated newborn piglets compared to 3:1 C:V resuscitation. However, the optimal length of SI during CC+SI is unknown. OBJECTIVES To examine if a 60sec SI compared to a 20sec SI or 3:1 C:V will reduce will reduces ROSC during resuscitation in asphyxiated newborn piglets. DESIGN/METHODS Cardiac arrest with achieved was induced in newborn piglets and then randomized to receive either “3:1 C:V ratio, SI+CC-20sec” or “SS+CC-60sec”. Piglets randomized to “SI+CC+20sec” or “SI+CC+60sec” received 90/min CC during a SI of 20sec or 60sec. Piglets randomized to 3:1 C:V received 90/min CC and 30 inflations/min. The default settings for airway pressures were peak inflation pressure of 30 cm H2O and a positive end expiratory pressure of 6 cm H2O. The primary outcome was duration of CC to achieve ROSC. RESULTS Eight piglets were randomized to each group; the mean (SD) age and weight was similar between groups. Median (IQR) ROSC was significantly shorter in the SI+CC-20sec and SI+CC-60sec group with 96 (68–168) sec and 78 (60–91) sec compared to the 3:1 C:V group with 235 (182–347)sec (p=0.002). 5/8 in the SI+CC-60sec group, 7/8 in the SI+CC-20sec and 8/8 in the 3:1 C:V group received epinephrine (p=0.82). CONCLUSION Lengths of SI during CC+SI does not affect ROSC, however CC+SI compared to 3:1 C:V does improve ROSC in newborn piglets.