Impact of bradycardia or asystole on neonatal cardiopulmonary resuscitation at birth

Background: Fetal hypoxia from intrapartum events can lead to absent heart rate (HR) or bradycardia at birth requiring aggressive neonatal resuscitation. Neonatal resuscitation guidelines do not differentiate bradycardia (HR <100 beats/min) from absent HR at birth. Given that HR is the primary determinant of resuscitation, we hypothesize that infants with no HR at 1 min would require more extensive resuscitation with worse clinical outcome than infants with bradycardia at 1 min. Methods: A retrospective analysis was performed in infants born between 1 January 2000 and 31 December 2015 with no HR at 1 min (defined as Apgar score [AS] = 0 at 1 min; absent HR [AHR] group) or bradycardia at 1 min (AS = 1 at 1 min). Patient demographics, resuscitation characteristics and clinical outcomes were analyzed in both the groups. Results: Apgar score was significantly lower in the AHR group over time. The AHR group had significantly higher rates of intubation, chest compression (CC) and i.v. epinephrine (i.v. epi); resulting in longer duration of CC, time to HR > 100 beats/min and duration of resuscitation. Systematic hypotension and death were higher in the AHR group. On logistic regression, CC and cord pH were significantly correlated with AS = 0 at 1 min. Gestational age, birthweight, AS at 5 min, cord pH and first blood gas pH after resuscitation were related to overall mortality. Conclusions: Infants with AHR at 1 min did worse than infants with bradycardia. Education focused on effective positive pressure ventilation and early use of i.v. epinephrine is essential for successful resuscitation of the depressed newborn.