Perfusion Pressure Deficits as Early Indicators of Abdominal Compartment Syndrome After Neonatal Congenital Diaphragmatic Hernia Repair: A Retrospective Cohort Study.

(1) Background: Abdominal compartment syndrome (ACS) after congenital diaphragmatic hernia (CDH) repair is an infrequent but potentially life-threatening consequence of viscero-abdominal disproportion. Because static intra-abdominal pressure (IAP) thresholds may not capture hypoperfusion, this study assessed whether early postoperative deficits in mean arterial pressure (MAP) and abdominal perfusion pressure (APP) could serve as early indicators of ACS. (2) Methods: We performed a retrospective cohort analysis of neonates with CDH admitted between January 2022 and June 2025. APP was calculated as MAP minus IAP. Two deficit features were defined: the maximum decrease in APP below 45 mmHg and MAP below 55 mmHg within the 72 h after surgical repair. A penalized logistic regression model with leave-one-out cross-validation assessed discriminative ability. (3) Results: Among 28 patients, two developed ACS. Median minimum MAP and APP were lower in the ACS group (35.7 mmHg and 27.7 mmHg, respectively) than in the non-ACS group (48 mmHg and 40.3 mmHg, respectively). The penalized model achieved an exploratory ROC-AUC of 0.942 (95% CI 0.808-1). Deficit features were computed before clinical decompensation. (4) Conclusions: Early MAP and APP deficits may provide physiologic warning signal for ACS after CDH, warranting prospective multicenter validation.