title: Nonelective surgery at night and in-hospital mortality: Prospective observational data from the European Surgical Outcomes Study.
abstract: 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.
  
  
  METHODS
  A prospective cohort study. This is a secondary analysis of a large database related to perioperative care and outcome (European Surgical Outcome Study).
  
  
  METHODS
  Four hundred and ninety-eight hospitals in 28 European countries.
  
  
  METHODS
  Men and women older than 16 years who underwent nonelective, noncardiac surgery were included according to time of the procedure.
  
  
  METHODS
  None.
  
  
  METHODS
  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%)].
  
  
  CONCLUSIONS
  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.
  
  
  BACKGROUND
  Clinicaltrials.gov identifier: NCT01203605.
authors.affiliation: From the Department of Anaesthesiology, University Medical Centre Utrecht, Utrecht (BVZ,WAVK), Department of Anaesthesiology, Maastricht University Medical Centre, Maastricht, the Netherlands (WFB), Section of Medical Statistics, Medical University of Vienna, Vienna, Austria (PB), Department of Intensive Care, Medical Centre Leeuwarden, Leeuwarden, the Netherlands (ECB), Department of Anaesthesiology, University of Bonn, Bonn, Germany (AH), Department of General Anaesthesiology, Emergency and Intensive Care Medicine, Medical University of Graz, Graz, Austria (PM), UCINC, Hospital de São José, Centro Hospitalar de Lisboa Central, EPE, Lisbon, Portugal (RPM), Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Department of intensive care, London, UK (RP), IRCCS AOU San Martino-IST (RP), Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genova, Italy (PP), Charité-Universitaetsmedizin, Department of Anaesthesiology (MS), Anaesthesiology and Critical Care, University Hospital Lille, Lille, France (BV), Intensive Care Units, Helsinki University Hospital, Helsinki, Finland (VP), Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium (J-LV), and St George's Healthcare NHS Trust, London, UK (AR) *Members listed in appendix I, http://links.lww.com/EJA/A68.
authors.forename: Bas
authors.initials: B
authors.lastname: van Zaane
authors.forename: Wilton A
authors.initials: WA
authors.lastname: van Klei
authors.forename: Wolfgang F
authors.initials: WF
authors.lastname: Buhre
authors.forename: Peter
authors.initials: P
authors.lastname: Bauer
authors.forename: E Christiaan
authors.initials: EC
authors.lastname: Boerma
authors.forename: Andreas
authors.initials: A
authors.lastname: Hoeft
authors.forename: Philipp
authors.initials: P
authors.lastname: Metnitz
authors.forename: Rui P
authors.initials: RP
authors.lastname: Moreno
authors.forename: Rupert
authors.initials: R
authors.lastname: Pearse
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
authors.forename: Michael
authors.initials: M
authors.lastname: Sander
authors.forename: Benoit
authors.initials: B
authors.lastname: Vallet
authors.forename: Ville
authors.initials: V
authors.lastname: Pettilä
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Vincent
authors.forename: Andrew
authors.initials: A
authors.lastname: Rhodes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D004632:Emergency Medical Services; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009551:Night Care / Q000706:statistics & numerical data*; D011446:Prospective Studies; D018401:Sample Size; D066231:Surgeons; D013514:Surgical Procedures, Operative / Q000009:adverse effects / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D055815:Young Adult