ObjectiveA small percentage of infants with d-loop transposition of the great arteries with intact intraventricular septum have life-threatening refractory hypoxemia often due to coexistent persistent pulmonary hypertension of the newborn. In this case series we describe the outcomes of a “rescue” emergency arterial switch operation (ASO). MethodsWe undertook a retrospective medical record analysis of infants with d-loop transposition of the great arteries with intact intraventricular septum who underwent an ASO in New Zealand from January 1, 1996, to April 30, 2017. Data were compared for those who received an emergency ASO and those with a nonemergency ASO for descriptive purposes. An emergency ASO was defined as one that was undertaken for life-threatening refractory hypoxemia when the only alternative stabilization strategy was preoperative extracorporeal life support. Primary outcome measures were 30-day postoperative mortality and abnormal neurodevelopmental outcome in the survivors. Secondary outcomes were low cardiac output, arrhythmia, renal dysfunction, postoperative seizures, and length of stay. Other known risk factors for morbidity and mortality were also assessed. ResultsTwo hundred seventy-two infants underwent an ASO with 25 (9%) who received an emergency ASO. No infants received preoperative extracorporeal life support. The emergency group had greater 30-day postoperative mortality (8.0% vs 0.4%; P = .01) with no difference in abnormal neurodevelopmental outcome among the survivors (17.4% vs 13.8%; P = .35). The emergency group had more therapies for low cardiac output syndrome, more postoperative seizures, and a longer length of stay. ConclusionsAn emergency ASO is a definitive rescue therapy that can be undertaken with acceptable mortality and neurodevelopmental outcome with consideration of the preoperative clinical state.