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Effects of the Introduction of the WHO “Surgical Safety Checklist” on In-Hospital Mortality: A Cohort Study

van Klei, W. A. MD, PhD*; Hoff, R. G. MD, PhD*; van Aarnhem, E. E. H. L. MD; Simmermacher, R. K. J. MD, PhD; Regli, L. P. E. MD, PhD§; Kappen, T. H. MD*; van Wolfswinkel, L. MD, PhD*; Kalkman, C. J. MD, PhD*; Buhre, W. F. MD, PhD*; Peelen, L. M. PhD*,¶

doi: 10.1097/SLA.0b013e31823779ae
Original Articles

Objective: To evaluate the effect of implementation of the WHO's Surgical Safety Checklist on mortality and to determine to what extent the potential effect was related to checklist compliance.

Background: Marked reductions in postoperative complications after implementation of a surgical checklist have been reported. As compliance to the checklists was reported to be incomplete, it remains unclear whether the benefits obtained were through actual completion of a checklist or from an increase in overall awareness of patient safety issues.

Methods: This retrospective cohort study included 25,513 adult patients undergoing non-day case surgery in a tertiary university hospital. Hospital administrative data and electronic patient records were used to obtain data. In-hospital mortality within 30 days after surgery was the main outcome and effect estimates were adjusted for patient characteristics, surgical specialty and comorbidity.

Results: After checklist implementation, crude mortality decreased from 3.13% to 2.85% (P = 0.19). After adjustment for baseline differences, mortality was significantly decreased after checklist implementation (odds ratio [OR] 0.85; 95% CI, 0.73–0.98). This effect was strongly related to checklist compliance: the OR for the association between full checklist completion and outcome was 0.44 (95% CI, 0.28–0.70), compared to 1.09 (95% CI, 0.78–1.52) and 1.16 (95% CI, 0.86–1.56) for partial or noncompliance, respectively.

Conclusions: Implementation of the WHO Surgical Checklist reduced in-hospital 30-day mortality. Although the impact on outcome was smaller than previously reported, the effect depended crucially upon checklist compliance.

Supplemental Digital Content is available in the text.The use of surgical checklists reduces the rate of in-hospital complications, including mortality. The decrease in mortality associated with the introduction of a surgical checklist was less than anticipated and seems to be associated with full checklist compliance and not with an overall increased awareness of patient safety issues.

*Division of Perioperative Care and Emergency Medicine

Division of Heart and Lungs

Division of Surgical Specialties

§Division of Neurosciences

Division Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, Utrecht, NL.

Reprints: Wilton A. van Klei, MD, PhD, Anesthesiologist, Division of Perioperative Care and Emergency Medicine, Local mail Q04.2.313, University Medical Centre Utrecht, PO box 85500, 3508 GA Utrecht, NL. E-mail:

Disclosure: Supported by departmental sources only.

All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare that none of the authors have support from a company for the submitted work; none have relationships with companies that might have an interest in the submitted work in the previous 3 years; their spouses, partners, or children have no financial relationships that may be relevant to the submitted work; and none have nonfinancial interests that may be relevant to the submitted work.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (

Ethical approval: According to Dutch law, as only routinely collected patient data were used and data were anonymized before analysis, hospital ethics board approval was not required.

© 2012 Lippincott Williams & Wilkins, Inc.