Postoperative Fever in Children Hospitalized After Surgery: Incidence and Risk Factors

BACKGROUND AND OBJECTIVES: Pediatricians increasingly engage in medical cotreatment of pediatric patients undergoing surgical procedures. Understanding the natural history of postoperative fever (PoF) is paramount. We assessed the incidence of PoF by surgical procedure as well as patient- and procedure-level risk factors among children hospitalized after surgery. METHODS: This study is a retrospective analysis of inpatient surgical admissions at a children's hospital from January 1, 2016 to December 31, 2023. PoF was defined as a body temperature of 38.0 °C or higher within 7 days after surgery. Mixed-effects logistic regression was used to assess risk factors for PoF, including number of chronic conditions, weight Z score, operative duration, and demographics. RESULTS: Of 35 030 hospitalizations, 20.3% of patients had PoF. Of encounters with PoF, the median peak temperature was 38.4 °C (IQR: 38.1-38.9), occurring at a median of 26.7 hours postoperatively (IQR: 10.9-52.2). PoF rate by procedure domain ranged from 8.1% for ophthalmologic to 35.2% for cardiovascular. In a multivariable analysis, controlling for procedure type, the highest adjusted odds ratios (aOR) for PoF occurred with an operative duration of 6 or more hours vs less than 2 hours (aOR: 2.72 [95% CI, 2.44-3.04]), patients aged 1 year to 4 years vs 16 years to 21 years at procedure (aOR: 2.09 [95%, CI 1.87-2.34]), weight Z scores of less than -2 vs more than 2 (aOR: 1.46 [95% CI, 1.24-1.72]), and 9 or more vs 0 to 1 body systems affected by chronic condition (aOR: 1.29 [95% CI, 1.13-1.49]). CONCLUSIONS: PoF occurred in 1 in 5 cases, with the rate varying substantially by procedure. Longer operative time, younger age at procedure, lower weight Z score, and greater number of chronic conditions were positively associated with PoF.