Background: Cardiopulmonary collapse can occur in newborns with Right Atrial Isomerism (RAI) and functional single ventricle due to increased pulmonary blood flow, atrial septal defect (ASD), changes in pulmonary vascular resistance, prematurity, and low birth weight. Anomalous pulmonary venous drainage is frequently encountered in RAI, a classic study of 116 patients reported anomalous pulmonary venous connections in 52% of cases, with pulmonary venous obstruction as a significant risk factor for mortality. This case highlights the challenges of stabilizing complex single-ventricle physiology in resource-limited setting where definitive cardiac intervention is not immediately available.

Case Presentation: A female neonate delivered by C-section at 36-37 weeks of gestation with a birth weight of 2.200 grams. Shortly after birth, the patient developed apnea and cardiac arrest, with subsequent return of spontaneous circulation (ROSC), and was reffered for mechanical ventilatory support. Upon arrival, oxygen saturation was 68%, accompanied by perioral cyanosis, cold extremities, and weak peripheral pulses. Transvaginal ultrasound examination was performed as an alternative bedside imaging modality, demonstrated a short-axis view with a D-shaped left ventricle (LV), suggesting right ventricular pressure overload. Echocardiography RAI and functional single-ventricle physiology, with suspected partial anomalous pulmonary venous return (PAPVR). Management included mechanical ventilation, partial parenteral nutrition and titrated norepinephrine infusion. Rather than attempting to normalize oxygen saturation, a target saturation of 76% was maintained while systemic perfusion was closely monitored. The patient gradually stabilized and was successfully weaned off oxygen after 7 days of hospitalization.

Conclusion: This case illustrates the challenges of initial stabilization in neonates with complex single-ventricle physiology when definitive cardiac intervention is not immediately available. In complex single-ventricle physiology, stabilization should prioritize systemic perfusion and balanced pulmonary/systemic blood flow rather than normalization of oxygen saturation.

Ni Made Dwiyathi Utami is a first-semester resident in the Neonatology Fellowship Program (PPDS 2) at Prof. Kandou General Hospital, Manado. She previously served as a pediatrician in a remote and underserved area of Indonesia, Southwest Sumba Regency, East Nusa Tenggara Province, where she provided pediatric healthcare services to communities with limited access to medical facilities. She is a young and enthusiastic researcher with a strong passion for academic work and scientific contributions. To date, four of her scientific papers have been published in academic journals. She is committed to continuously developing her knowledge and skills in neonatology while contributing to research and improving the quality of neonatal and pediatric care.