Neonatal resuscitation for bradycardia (HR < 60 bpm)—an alternate approach using an ovine model

Background: The International Liaison Committee on Resuscitation recommends initiating chest compressions (CC) in newborns when heart rate (HR) is <60 beats per minute (bpm) after 30 s of effective positive pressure ventilation (PPV). Methods: Near-term lambs with asphyxia induced bradycardia (HR < 60 bpm) were randomized to: (i) control (n = 6)— Resuscitation per current Neonatal Resuscitation Program (NRP) (ii) study (n = 6)—PPV continued until HR = 0, only then CC with PPV were administered in a ratio of 3:1 until return of spontaneous circulation (ROSC). Outcomes included timing, incidence of ROSC, CC requirement, blood gases, and peak coronary, carotid, and pulmonary blood flow. Results: The time to achieve ROSC was not different between groups (3 ± 2 min vs. 1.6 ± 1 min in study (p = 0.17). Only 1/6 lambs in study group required CC versus 6/6 in control group (p = 0.015). At ROSC, the study group had significantly lower arterial PaCO2 (47 ± 5 mmHg vs. 94 ± 18 mmHg, p < 0.01) and higher arterial PaO₂ (148 ± 53 mmHg vs. 54 ± 12 mmHg, p < 0.01). The asynchronous external CC in the control group contributed to the loss of inherent cardiac activity. Conclusion: Prioritizing ventilation during bradycardia reduced need for CC, facilitated faster ROSC, and improved gas exchange in an ovine model. Impact: Prioritizing ventilation over chest compressions beyond 30 s for bradycardia during neonatal resuscitation improves outcomes, reducing the need for chest compressions and accelerating the time to return of spontaneous circulation. Pulseless electrical activity occurs before complete cardiac arrest. Focusing on initiating chest compressions at a specific heart rate will distract providers from prioritizing ventilation.