Background: There is conflicting data on whether surgery at night increases patient harm. We hypothesized that night surgery was associated with increased readmission and postoperative complications. Our primary outcome was 30-day readmission, and exploratory outcomes included adverse discharge (in-hospital mortality, or discharge to a nursing facility), 30-day mortality, and postoperative complications (respiratory, cardiovascular, acute kidney injury, and stroke).

Materials and Methods: 170,022 adults underwent noncardiac surgery with endotracheal intubation at Massachusetts General Hospital and two affiliated hospitals between 2007 and 2015. After excluding missing covariates, our cohort size was 153,460 with 8,281 nighttime surgeries (starting 5pm to 7am). This group was matched to an equal-sized cohort undergoing daytime surgery via propensity scores for confounding covariates, which included patient factors (gender, age, BMI, ASA class, SPORC, CCI), surgical factors (admission booking, urgent or emergent surgery, surgical service, duration of surgery, surgery year, work RVU), and anesthetic factors (vasopressor dose, hypotension, long and short-acting opioids, NMBAs, neostigmine, fluids, PRBCs, dose of volatile agents, nitrous oxide, and propofol, neuraxial use, and S/F ratio). Logistic regression modeling with respect to exposure variable and covariates was used to calculate the odds ratio of outcomes.

Results: Thirty-day readmission occurred in 13.7% of cases. Night surgery was not associated with higher odds of readmission (OR, 1.07, 95% CI 0.98-1.18, p=0.15). Adverse discharge and thirty-day mortality were not significantly different. Composite morbidity was not significantly increased (1.08, 0.99-1.18, p=0.08). However, night surgery was associated with significantly higher odds of respiratory complications and acute kidney injury (1.20, 1.08-1.33, p=0.001) and (1.30, 1.12-1.51, p=0.001), respectively.

Conclusions: We did not find that night surgery increases readmission. Though surgery at night cannot always be avoided, it is associated with increased pulmonary complications and acute kidney injury. This warrants further study and begs consideration when cases are booked to start during nighttime hours.
 



09 / Effect of night surgery on postoperative complications and healthcare utilization: A Prospective Analysis from New England Hospitals