Timing of pediatric pyloromyotomy on hospital length of stay

Introduction: Pyloromyotomy timing is predicated upon correction of electrolyte abnormalities. Among infants who presented with normal electrolytes, we hypothesized that pyloromyotomy the evening of presentation, rather than waiting until morning, would confer shorter length of stay (LOS). Methods: This single-center retrospective cohort study included patients who underwent pyloromyotomy from 2012 to 2021. Exposure was time of operation with nighttime considered between the times of 17:00 and 06:59 and daytime between 07:00 and 16:59. A 2:1 daytime to nighttime match was performed among patients who presented with normal electrolytes with Fisher's Exact and Student's t-test for comparisons. Results: Of 520 patients, 15 (3%) underwent pyloromyotomy overnight and were matched to 30 daytime patients. There were no differences in median age (33 days (interquartile range [IQR] 29-44) vs 32 days (IQR 25-44)), male sex (15 (100%) vs 28 (93.3%), or history of prematurity (0 (0%) vs 2 (6.7%)) for nighttime compared to daytime, respectively. Operative outcomes including conversion to open, duodenal perforation, incomplete myotomy, or surgical site infection did not differ between the groups. While the nighttime group had a significantly shorter time from presentation to operating room (OR) than the daytime group (5.3 vs 15.9 h), there were no significant differences in total LOS (45.7 vs 57.3 h, p = 0.13). Conclusion: For infants with hypertrophic pyloric stenosis who present with normal electrolytes, it is safe to offer operation same-day or following a night of hydration. There was no evidence of improved hospital utilization for patients undergoing pyloromyotomy the night of presentation.