BACKGROUND 

A recent prospective study reported a decrease in postoperative mortality when cardiac surgery was started in the afternoon instead of in the morning. In contrast, several large retrospective analyses have not confirmed this finding. Larger prospective studies are required to elucidate the effects of circadian rhythm on postoperative outcomes.

OBJECTIVE 

To identify any relation between starting time of anaesthesia/surgery and postoperative outcomes in patients aged 80 years or older to aid in clinical decision making with regard to scheduling surgery.

DESIGN 

A multivariable model with a priori defined confounders was constructed to evaluate the impact of anaesthesia starting time on hospital length of stay and postoperative complications.

SETTING 

A European multicentre, observational study of outcomes after geriatric anaesthesia from October 2017 to December 2018.

PATIENTS 

Patients aged 80 years or older having major elective or urgent intervention with anaesthesia starting time between 7 a.m. and 7 p.m.

MAIN OUTCOME MEASURE 

Primary outcome measure was the difference in hospital length of stay after any major elective or urgent morning or afternoon intervention.

RESULTS 

We included 3551 patients of whom 2592 had an intervention starting in the morning (7 a.m. to 1 p.m.). These patients, compared with those with interventions in the afternoon (1 p.m. to 7 p.m.), were slightly younger, were less frail but had a longer duration of the intervention. Hospital length of stay or postoperative complications were not different between morning or afternoon interventions. Multivariable analysis showed no impact of time of anaesthesia (morning vs. afternoon) on hospital length of stay or postoperative complications, hazard ratio of 1.03 (95% CI 0.94 to 1.12) and odds ratio of 1.13 (95% CI 0.92 to 1.39), respectively.

CONCLUSION 

Our results do not support the hypothesis of circadian effects on postoperative outcomes for elective and urgent major interventions in patients at least 80 years of age.