DOI: 10.6084/m9.figshare.27888957.v1
title: Daytime variation of in-hospital mortality and low cardiac output syndrome after pediatric cardiac surgery-a retrospective cohort study

description: Recent studies suggest that adult cardiac surgery performed in the morning increases the risk of major adverse cardiac events, but it is unclear whether this association exists in pediatric cardiac surgery. This study aimed to determine whether the composite outcome of in-hospital mortality and low cardiac output syndrome (LCOS) differs between morning and afternoon pediatric cardiac surgeries. This retrospective cohort study enrolled 23,433 consecutive pediatric patients who underwent cardiac surgery between August 2014 and December 2021. Pediatric patients who had surgery start time between 8 AM and 11 AM (morning surgery) versus between 2 PM and 5 PM (afternoon surgery) were compared in the risk of the composite outcome. The Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery (STAT) score was used to indicate the surgical complexity. The adjusted odds radio (aOR) for the composite outcome was calculated using multivariate logistic regression. The restricted cubic spline (RCS) was performed to characterize the continuous relationship between the surgery start time and risk of the composite outcome. Of 16,534 included pediatric patients, 1.2% died after morning surgery and 0.6% died after afternoon surgery. The composite outcome of in-hospital mortality and LCOS occurred in 14.2% (1,507 of 10,591) of morning surgeries and 8.6% (514 of 5,943) of afternoon surgeries: morning versus afternoon aOR, 1.186 (95% CI, 1.046 to 1.344; <i>p</i> = 0.008). The association was also determined in children aged 3 to 18 years (aOR = 1.598, <i>p</i> = 0.003), weighted between 6.1 to 8.7 kg (aOR = 1.453, <i>p</i> = 0.006), or more than 13 kg (aOR = 1.488, <i>p</i> = 0.019), and with STAT category 4-5 (aOR = 1.367, <i>p</i> = 0.014) subgroups. The RCS plot showed that the aOR of the composite outcome decreased with a delay in the start time of surgery. Our study supports the selective afternoon scheduling of specific pediatric cardiac surgeries, but further investigation is needed in a multicenter cohort.KEY MESSAGESThis study reviewed 23,433 consecutive pediatric patients who underwent cardiac surgery between August 2014 and December 2021.This study suggested that afternoon surgery was associated with a lower risk of the composite outcomes of in-hospital mortality and low cardiac output syndrome.The above association was also determined in children aged 3 to 18 years, weighted between 6.1 and 8.7 kg, or more than 13 kg, and with STAT category 4-5 subgroups.The restricted cubic spline plot showed that the adjusted risk of the composite outcome decreased with a delay in the start time of surgery.Our findings support selective afternoon scheduling for specific pediatric cardiac surgery. This study reviewed 23,433 consecutive pediatric patients who underwent cardiac surgery between August 2014 and December 2021. This study suggested that afternoon surgery was associated with a lower risk of the composite outcomes of in-hospital mortality and low cardiac output syndrome. The above association was also determined in children aged 3 to 18 years, weighted between 6.1 and 8.7 kg, or more than 13 kg, and with STAT category 4-5 subgroups. The restricted cubic spline plot showed that the adjusted risk of the composite outcome decreased with a delay in the start time of surgery. Our findings support selective afternoon scheduling for specific pediatric cardiac surgery.