Sex-specific associations between cerebrovascular blood pressure autoregulation and cardiopulmonary injury in neonatal encephalopathy and therapeutic hypothermia

BACKGROUND: Cardiopulmonary injury is common in neonatal encephalopathy, but the link with cerebrovascular dysfunction is unknown. We hypothesized that cerebral autoregulation is associated with cardiopulmonary injury in neonates treated with therapeutic hypothermia (TH) for neonatal encephalopathy. METHODS: The cerebral hemoglobin volume index (HVx) from near-infrared spectroscopy was used to identify the mean arterial blood pressure (MAP) with optimal autoregulatory vasoreactivity (MAP(OPT)). We measured associations between MAP relative to MAP(OPT) and indicators of cardiopulmonary injury (duration of mechanical respiratory support and administration of inhaled nitric oxide (iNO), milrinone, or steroids). RESULTS: We identified associations between cerebrovascular autoregulation and cardiopulmonary injury that were often sex-specific. Greater MAP deviation above MAP(OPT) was associated with shorter duration of intubation in boys but longer ventilatory support in girls. Greater MAP deviation below MAP(OPT) related to longer intensive care stay in boys. Milrinone was associated with greater MAP deviation below MAP(OPT) in girls. CONCLUSION: MAP deviation from MAP(OPT) may relate to cardiopulmonary injury after neonatal encephalopathy, and sex may modulate this relationship. Whereas MAP above MAP(OPT) may protect the brain and lungs in boys, it may be related to cardiopulmonary injury in girls. Future studies are needed to characterize the role of sex in these associations.