Effect of Different Respiratory Modes on Return of Spontaneous Circulation in a Newborn Piglet Model of Hypoxic Cardiac Arrest

Abstract

Background: There are no clear evidence-based recommendations on the use of different techniques of respiratory support and chest compressions (CC) during neonatal cardiopulmonary resuscitation (CPR). Objectives: To determine the effects of different respiratory support strategies along with CC representing clinical practice on the return of spontaneous circulation (ROSC) in hypoxic newborn piglets with cardiac arrest. We hypothesized that use of a T-piece resuscitator (TPR) providing positive end-expiratory pressure (PEEP) reduces time to ROSC as compared to a self-inflating bag (SIB) without PEEP. Furthermore, we explored the effects of a ventilator providing inflations without synchrony to CC. Methods: Thirty-three newborn piglets were exposed to hypoxia until asystole occurred and randomized into three groups and resuscitated according to ILCOR guidelines: group 1 = TPR [peak inspiratory pressure (PIP)/PEEP of 25/5 cm H₂O, rate 30/min], inflations interposed between CC (3:1 ratio); group 2 = SIB (PIP of 25 cm H₂O without PEEP, rate 30/min), inflations interposed between CC (3:1 ratio), and group 3 = ventilator (PIP/PEEP of 25/5 cm H₂O, rate 30/min), CC were applied with a rate of 120/min without synchrony to inflations. Animals were supported for 120 min after ROSC. Primary outcome was time to ROSC. Results: All animals achieved ROSC. We found no significant difference in time to ROSC between groups [median (IQR); TPR: 150 s (150-210); SIB: 150 s (120-180); ventilator: 180 s (150-345)]. There was no difference in use of epinephrine, in blood gases or hemodynamic parameters during the 120-min observation time after ROSC. Conclusions: We found no significant effect of different respiratory support strategies during CPR on ROSC.