Fig. 1: Following instrumentation, near-term lambs of 138–140 days gestation were asphyxiated by umbilical cord occlusion until the heart rate (HR) was <60 bpm or diastolic blood pressure (DBP) was ≤10 mm Hg.
From: Neonatal resuscitation for bradycardia (HR < 60 bpm)—an alternate approach using an ovine model
The lambs were then randomized into either the control group (resuscitation following current NRP guidelines) or the study group. Positive pressure ventilation (PPV) was initiated with 21% oxygen. After 30 s of ventilation, oxygen was titrated up to 100%, and PPV was continued. Chest compressions (CC) were initiated in the study group only if bradycardia progressed to full arrest (HR = 0). Epinephrine (EPI) was administered in both groups according to NRP guidelines. Resuscitation continued until return of spontaneous circulation (ROSC) or for a maximum of 20 min. ROSC was defined as HR > 100 bpm and DBP ≥ 20 mmHg. The timing and incidence of ROSC, the need for CC, blood gas parameters, peak coronary blood flow (CoBF), peak left carotid blood flow (CaBF), and peak left pulmonary blood flow (PBF) were recorded. HR heart rate, DBP diastolic blood pressure, PPV positive pressure ventilation, CC chest compressions, ET endotracheal, EPI epinephrine, IV intravenous, ROSC return of spontaneous circulation.
