Association of timing of surgery and outcomes in preterm infants with surgical necrotizing enterocolitis and intestinal perforation

<b>Background:</b> To investigate the association between the timing of surgery from the day of NEC/SIP diagnosis and clinical outcomes in preterm infants. <b>Study Design:</b> A retrospective cohort study comparing clinical outcomes of infants undergoing laparotomy at three clinically relevant time points (less and more than 48 hours, 96 hours, and 168 hours [7 days]) following NEC/SIP diagnosis. <b>Results:</b> Infants with NEC/SIP (<i>N</i> = 97) receiving surgical invention >96 hours (34/97) had significantly lower gestational age (25.5 weeks [24.0; 26.9] vs 27.0 [25.0; 31.3]; <i>p</i> = 0.006), had lower birth weight (687 grams [600; 902] vs 940 [710; 1495]; <i>p</i><0.001), had pneumoperitoneum less often on the abdominal x-ray (29.4% vs 57.1%, <i>p</i> = 0.017), had hemorrhagic (<i>p</i> = 0.04) and reparative (<i>p</i> = 0.003) lesions more often on intestinal histopathology, had PDA diagnosed more often (76.5% vs 50.8%, <i>p</i> = 0.02), required assisted ventilation more frequently (<i>p</i> = 0.013), and received parenteral nutrition for longer duration (112 days [76.5; 145] vs 65.0 [23.0; 112], <i>p</i> = 0.004) following surgery compared to the infants receiving surgical intervention before 96 hours (<i>n</i> = 63/97). In NEC-only sub-cohort, infants receiving laparotomy >48 hours (<i>n</i> = 29/75) had lower median gestational age, lower birth weight, less pneumoperitoneum, and higher acute kidney injury than those receiving surgery <48 hours. On logistic regression, the odds of death were not significantly different (OR 0.65 [0.28, 1.54], <i>p</i> = 0.32) for infants receiving laparotomy ≤48 hours following NEC/SIP compared to subjects undergoing surgery >48 hours. The odds of intestinal failure (>60 days of parenteral nutrition) were 4.5 times (CI 1.56, 14.3), <i>p</i> = 0.005) higher for those having surgery >96 hours from NEC/SIP diagnosis. <b>Conclusion:</b> There was no significant difference in death among infants receiving surgery within 48 hours following surgical NEC/SIP diagnosis compared to those receiving surgery at ≥ 48 hours of diagnosis. However, infants receiving surgery >96 hours were more likely to receive parenteral nutrition for longer time. A prospective study is needed to understand the continuous relationship between time to surgery and outcomes.