Postoperative Pulmonary Hypertension after Primary Abdominal Wall Closure for Small Omphalocele: A Case Series

Primary closure is a low-risk option for small omphaloceles (SOs). However, despite the absence of liver herniation and limited volume of herniated viscera, we encountered two cases of postoperative pulmonary hypertension (PH) and respiratory failure after closure for SO. This report discusses the safety of primary closure and potential factors that may be associated with postoperative PH in infants with SOs. Cases 1 and 2 presented with SOs without chromosomal abnormalities or liver herniation (gestational ages 36 and 37 weeks, birth weights 3,650 and 2,577 g, and defect sizes 4 and 2 cm, respectively). Prenatal ultrasonography showed no evidence of oligohydramnios in either case, and chest radiography was negative for chest wall deformity at birth. Primary closure was performed within 24 hours of birth after stabilization, defined as venous blood gas values without hypoxia/CO ₂ retention, and echocardiographic confirmation of no PH. Arterial blood gas was assessed after abdominal wall closure and demonstrated critical respiratory failure with CO ₂ retention, and both infants developed postoperative PH. However, low Apgar scores were noted (at 1 minute: 4 and 6 and at 5 minutes: 6 and 6 in Cases 1 and 2, respectively). One infant died from refractory PH, but the other responded to treatment. Even in SO, preoperative respiratory reserve, including information reflected by Apgar scores, may be carefully considered when determining the timing and feasibility of primary closure.