Nonelective surgery at night and in-hospital mortality: Prospective observational data from the European Surgical Outcomes Study

European Surgical Outcomes Study (EuSOS) group for the Trials groups of the European Society of Intensive Care Medicine and the European Society of Anaesthesiology, Bas van Zaane (Coresponding Author), Wilton A van Klei, Wolfgang F Buhre, Peter Bauer, Sigita Kazūne (Member of the Working Group), Iveta Golubovska (Member of the Working Group), Oļegs Šuba (Member of the Working Group)

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Evidence suggests that sleep deprivation associated with night-time working may adversely affect performance resulting in a reduction in the safety of surgery and anaesthesia.

OBJECTIVE: Our primary objective was to evaluate an association between nonelective night-time surgery and in-hospital mortality. We hypothesised that urgent surgery performed during the night was associated with higher in-hospital mortality and also an increase in the duration of hospital stay and the number of admissions to critical care.

DESIGN: A prospective cohort study. This is a secondary analysis of a large database related to perioperative care and outcome (European Surgical Outcome Study).

SETTING: Four hundred and ninety-eight hospitals in 28 European countries.

PATIENTS: Men and women older than 16 years who underwent nonelective, noncardiac surgery were included according to time of the procedure.


MAIN OUTCOME MEASURES: Primary outcome was in-hospital mortality; the secondary outcome was the duration of hospital stay and critical care admission.

RESULTS: Eleven thousand two hundred and ninety patients undergoing urgent surgery were included in the analysis with 636 in-hospital deaths (5.6%). Crude mortality odds ratios (ORs) increased sequentially from daytime [426 deaths (5.3%)] to evening [150 deaths (6.0%), OR 1.14; 95% confidence interval 0.94 to 1.38] to night-time [60 deaths (8.3%), OR 1.62; 95% confidence interval 1.22 to 2.14]. Following adjustment for confounding factors, surgery during the evening (OR 1.09; 95% confidence interval 0.91 to 1.31) and night (OR 1.20; 95% confidence interval 0.9 to 1.6) was not associated with an increased risk of postoperative death. Admittance rate to an ICU increased sequentially from daytime [891 (11.1%)], to evening [347 (13.8%)] to night time [149 (20.6%)].

CONCLUSION: In patients undergoing nonelective urgent noncardiac surgery, in-hospital mortality was associated with well known risk factors related to patients and surgery, but we did not identify any relationship with the time of day at which the procedure was performed.

TRIAL REGISTRATION: identifier: NCT01203605.

Original languageEnglish
Pages (from-to)477-85
Number of pages9
JournalEuropean Journal of Anaesthesiology
Issue number7
Publication statusPublished - 10 Jul 2015
Externally publishedYes


  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Cohort Studies
  • Comorbidity
  • Emergency Medical Services
  • Female
  • Hospital Mortality
  • Humans
  • Male
  • Middle Aged
  • Night Care/statistics & numerical data
  • Prospective Studies
  • Sample Size
  • Surgeons
  • Surgical Procedures, Operative/adverse effects
  • Treatment Outcome
  • Young Adult

Field of Science*

  • 3.2 Clinical medicine
  • 3.3 Health sciences

Publication Type*

  • 1.1. Scientific article indexed in Web of Science and/or Scopus database


Dive into the research topics of 'Nonelective surgery at night and in-hospital mortality: Prospective observational data from the European Surgical Outcomes Study'. Together they form a unique fingerprint.

Cite this