Distinctive clinical features of spontaneous pneumoperitoneum in neonates: A retrospective analysis

Spontaneous pneumoperitoneum (SP) without gastrointestinal perforation rarely occurs in neonates, with most SP cases being idiopathic. Although SP usually follows a benign clinical course with favorable prognosis, it can become life-threatening in certain situations. In these cases, urgent surgical intervention may be required. Therefore, it may be difficult to decide when or how to perform prompt interventions.

To demonstrate the distinct clinical features of SP to guide appropriate management by comparing characteristics between SP and typical pneumoperitoneum secondary to gastrointestinal perforation.

We retrospectively reviewed electronic medical records and identified 37 neonates with radiological evidence of pneumoperitoneum who were treated at our institution. Clinical variables were compared between neonates with SP without gastrointestinal perforation (Group A) and those with pneumoperitoneum secondary to gastrointestinal perforation (Group B). Clinical variables between groups were compared using Student's t-test and the chi-square test. The risk factors related to mortality were examined using multi-logistic regression analysis.

Group A comprised 35.1% (13/37) of the patients. The frequency of persistent pulmonary hypertension (53.8%) and pneumothorax (46.2%) before the development of pneumoperitoneum was significantly higher in group A than in group B (P = 0.004). Platelet count and partial pressure of arterial oxygen (PaO2) were significantly lower in group A (P = 0.015 and 0.025, respectively). Overall mortality was significantly higher in group A than in group B (76.9% vs 16.7%, P = 0.001). Only preterm infants were significantly associated with high mortality (P = 0.041; odds ratio = 18.0). Accompaniment with persistent pulmonary hypertension and pneumothorax were also significantly high (P = 0.004) in group A, but these were not strongly associated with high mortality.

This study identified a higher mortality rate in patients with SP than that described in previous reports. Neonates with SP were more likely to have thrombocytopenia, pneumothorax, and persistent pulmonary hypertension. Prematurity was the most significant factor affecting mortality.