Background: The incidence of in-hospital adverse events is about 10%, with a majority of these related to surgery, and nearly half considered preventable events. In attempts to improve patient safety, the World Health Organization (WHO) developed a checklist to be used at critical perioperative moments. This meta-analysis examines the impact of the WHO surgical safety checklist (SSC) on various patient outcomes. Methods: A comprehensive search of all published studies assessing the use of the WHO SSC in patients undergoing surgery was conducted. Studies using the WHO SSC in any surgical setting, with pre-implementation and post-implementation outcome data were included. The incidence of patient outcomes (total complications, surgical site infections, unplanned return to the operating room (OR) within 30 days, and overall mortality) and adherence to safety measures were analyzed. Results: 10 studies involving 51,125 patients (27,490 prior to implementation and 23,635 after implementation of the WHO SSC) were analyzed. The implementation of the WHO SSC significantly reduced the risk of total complications by 37.9%, surgical site infections by 45.5%, unplanned return to OR by 32.1%, and mortality by 15.3%. Increased adherence to safety measures including airway evaluation, use of pulse oximetry, prophylactic antibiotics when necessary, confirmation of patient name and surgical site, and sponge count was also observed. Conclusions: The use of the WHO SSC is associated with a significant reduction in post-operative complication rates and mortality. The WHO SSC is a valuable tool that should be universally implemented in all surgical centers and utilized in all surgical patients.
Approximately 321 million surgical procedures are performed annually throughout the world, or approximately one operation annually for every 25 people [
In attempts to improve overall patient safety, the World Health Organization (WHO) developed a checklist, consisting of 22-items to be used at critical perioperative moments: induction, incision, and before leaving the operating room (OR) [
Haynes et al. (2009) published the first study evaluating the effectiveness of the WHO surgical safety checklist [
Despite the benefits reported, compliance with the safety checklist has been low [
Bergs et al. conducted a meta-analysis including 6 studies involving 40,711 patients (17,920 patients pre- implementation and 22,791 patients post-implementation) and demonstrated significant overall reductions in overall complications (RR = 0.59; 95% CI, 0.47 - 0.74; p < 0.001), SSIs (RR = 0.57; 95% CI, 0.41 - 0.79; p < 0.001), and overall mortality (RR = 0.77; 95% CI, 0.60 - 0.98; p = 0.035) following the implementation of a surgical safety checklist [
Several more recent studies not included in the meta-analysis by Bergs et al. have subsequently been published with conflicting results. Biskup et al. conducted a study in the United States involving 4,476 patients undergoing plastic surgery (2166 patients before implementation and 2,310 patients after implementation) and reported no significant reductions in postoperative complications (5.8% vs. 6.0%, p = 0.830) or mortality (0.04% vs. 0.05%, p = 0.549) with the use of the WHO surgical safety checklist in plastic surgery [
This meta-analysis provides an updated comprehensive perspective on the impact of the WHO surgical safety checklist on the incidences of overall complications, SSIs, unplanned return to the OR within 30 days, and overall mortality.
A comprehensive search of all published studies evaluating the use of the WHO surgical safety checklist in patients undergoing surgery was conducted using PubMed, Cochrane Central Registry of Controlled Trials, and Google Scholar from the time the WHO surgical safety checklist was introduced to the current time (2008-2016) (
Articles retrieved from the searches were assessed for eligibility, and data pertaining to patients, intervention, control groups, outcomes, and methodology, were abstracted.
Primary clinical outcomes of interest included the incidences of various patient outcomes-total complications, SSIs, unplanned return to the OR within 30 days, and overall mortality. Total complications were defined as complications occurring prior to hospital discharge or the first 30 days of hospital stay according to the American College of Surgeons’ National Surgical Quality Improvement Program: acute renal failure, bleeding requiring the transfusion of four or more units of red cells within the first 72 hours after surgery, cardiac arrest requiring cardiopulmonary resuscitation, coma of 24 hours or longer, deep vein thrombosis, myocardial infarction, unplanned intubation, ventilator use of 48 hours or more, pneumonia, pulmonary embolism, stroke, major disruption of wound, SSI, sepsis, septic shock, systemic inflammatory response syndrome, unplanned return to the OR, vascular graft failure, and death [
Adherence to safety measures (airway evaluation, use of pulse oximeter, presence of catheter lines, prophylactic antibiotics, confirmation of patient and surgical site, and sponge count) were also analyzed.
For each trial, relative risk (RR) with a 95% confidence interval (95% CI) for incidence of total complications, SSIs, unplanned return to the OR within 30 days, and overall mortality were calculated. RR and 95% CI for
adherence to each safety measure (airway evaluation, use of pulse oximeter, presence of intravenous line, prophylactic antibiotics, confirmation of patient and surgical site, and sponge count) were also calculated. Meta- analysis of the pooled data was performed using the Comprehensive Meta-Analysis software Version 3 (Biostat, Englewood, NJ, USA). For studies reporting zero events in any group, a continuity correction factor of 0.5 was adopted to calculate the RR and variance. In the event of zero events in both groups, the RR was not calculable and the study was excluded from the meta-analysis. Both the fixed-effects model and random-effects model were considered, depending on the heterogeneity of the included studies. To assess the heterogeneity between studies, both Cochrane’s Q statistic and I2 statistic was used. Heterogeneity was considered statistically significant when p < 0.05 or I2 > 50. If heterogeneity was observed, data was analyzed using a random-effects model. Conversely, in the absence of heterogeneity, a fixed-effects model was assumed. Risk of bias among the included studies was assessed using the Cochrane Collaboration Risk of Bias tool. Publication bias regarding the primary outcome (overall mortality) was first visually evaluated by a funnel plot, and further evaluated using Egger’s and Begg’s tests. A two-tailed p-value of < 0.05 was considered statistically significant. Subgroup analysis was performed based on country economic income status?upper economic income countries (with a gross national income (GNI) per capita of over $12,736 USD) versus lower/middle economic income countries (GNI per capita of $1046 - $4125 USD), as defined by country economic income according to the World Bank [
A total of 10 studies meeting the inclusion criteria were identified. The 10 studies involved a total of 51,125 patients (
Data on the incidence of total complications were reported in 8 trials, involving 25,450 patients (13,039 pre-im- plementation and 12,411 post-implementation). There were fewer complications following the implementation of the WHO surgical safety checklist (1,078/12,411 [8.7%] vs. 2,047/13,039 [15.7%]). There was significant heterogeneity between trials (p < 0.001, I2 = 77.325), and a random-effects model was assumed. Meta-analysis showed a significant reduction in the risk of complications by 37.9% (RR = 0.621; 95% CI, 0.519 - 0.742; p < 0.001) (
There was a significant reduction in the risk of complications following the implementation of the WHO surgical safety checklist in both upper (RR = 0.718; 95% CI, 0.600 - 0.860; p < 0.001) and lower/middle economic income country hospitals (RR = 0.539; 95% CI, 0.406 - 0.715; p < 0.001). Subgroup analysis identified a slightly greater reduction in the risk of complications with the use of the WHO surgical safety checklist among lower/middle economic income country hospitals, compared to upper economic income country hospitals, although this was not statistically significant (p = 0.092).
Data on the incidence of SSIs were reported in 8 trials, involving 21,076 patients (10,902 pre-implementation and 10,174 post-implementation). There were fewer SSIs following the implementation of the WHO surgical safety checklist (332/10,174 [3.3%] vs. 819/10,902 [7.5%]). There was significant heterogeneity between trials (p < 0.001, I2 = 70.841), and a random-effects model was assumed. Meta-analysis showed a significant reduction in the risk of SSIs by 45.5% (RR = 0.545; 95% CI, 0.416 - 0.714; p < 0.001) (
There was a significant reduction in the risk of SSIs following the implementation of the WHO surgical safety checklist in both upper (RR = 0.705; 95% CI, 0.560 - 0.888; p = 0.003) and lower/middle economic income country hospitals (RR = 0.440; 95% CI, 0.300 - 0.645; p < 0.001). Subgroup analysis identified a significantly greater risk reduction in SSIs with the use of the WHO surgical safety checklist among lower/middle economic income country hospitals, compared to upper economic income country hospitals (p = 0.039).
Data on the number of unplanned returns to the OR were reported in 5 trials, involving 18,209 patients (8507
Study | Location | Age | Type of Surgery | Number of Patients (# Pre-/# Post-implementation) | Total Complications | Surgical Site Infections | Unplanned Returns to the OR | Mortality |
---|---|---|---|---|---|---|---|---|
Haynes, 2009 [ | Multicenter world-wide | Patients > 16 years | Non-cardiac surgeries | Total: 7688 (3733/3955) | ||||
Site 1: 1122 (524/598) | 11.6% vs. 7.0% | 4.0% vs. 2.0% | 4.6% vs. 1.8% | 1.0% vs. 0.0% | ||||
Site 2: 708 (357/351) | 7.8% vs. 6.3% | 2.0% vs. 1.7% | 0.6% vs. 1.1% | 1.1% vs. 0.3% | ||||
Site 3: 983 (497/486) | 13.5% vs. 9.7% | 5.8% vs. 4.3% | 4.6% vs. 2.7% | 1.0% vs. 1.4% | ||||
Site 4: 1065 (520/545) | 7.5% vs. 5.5% | 3.1% vs. 2.6% | 2.5% vs. 2.2% | 1.0% vs. 0.6% | ||||
Site 5: 700 (370/330) | 21.4% vs. 5.5% | 20.5% vs. 3.6% | 1.4% vs. 1.8% | 1.4% vs. 0.0% | ||||
Site 6: 972 (496/476) | 10.1% vs. 9.7% | 4.0% vs. 4.0% | 3.0% vs. 3.2% | 3.6% vs. 1.7% | ||||
Site 7: 1110 (525/585) | 12.4% vs. 8.0% | 9.5% vs. 5.8% | 1.3% vs. 0.2% | 2.1% vs. 1.7% | ||||
Site 8: 1028 (444/584) | 6.1% vs. 3.6% | 4.1% vs. 2.4% | 0.5% vs. 1.2% | 1.4% vs. 0.3% | ||||
Sewell, 2011 [ | London, UK | Patients of all ages | Elective and emergent orthopedic surgeries | 965 (480/485) | 8.5% vs. 7.6% | 4.4% vs. 3.5% | 1.0% vs. 1.0% | 1.9% vs. 1.6% |
Askarian, 2011 [ | Shiraz, Iran | Patients > 16 years | Elective general surgeries | 294 (144/150) | 22.9% vs. 10.0% | 10.4% vs. 5.3% | NR | NR |
Van Klei, 2012 [ | Utrecht, The Netherlands | Adult patients | Any surgical procedure | 25,513 (14,362/11,151) | NR | NR | NR | 3.1% vs. 2.9% |
Bliss, 2012 [ | Connecticut, USA | Not indicated | Any surgical procedure | 2152 (2,079/73) | 23.6% vs. 8.2% | 6.2% vs. 5.5% | NR | NR |
Yuan, 2012 [ | Liberia | Not indicated | Any surgical procedure | Total: 481 (232/249) Site 1: 219 (109/110) Site 2: 262 (123/139) | 15.6% vs. 12.7% 41.5% vs. 23.0% | 12.8% vs. 9.1% 39.8% vs. 10.1% | NR | 0.9% vs. 4.5% 0.3% vs. 1.4% |
Kwok, 2013 [ | Chisinau, Moldova | Patients of all ages | Any surgical procedure | 4099 (1993/2106) | 21.5% vs. 8.8% | 14.9% vs. 4.7% | 1.9% vs. 1.5% | 4.0% vs. 3.1% |
Lepanluoma, 2014 [ | Turku, Finland | Adult patients | Neurosurgery | 162 (89/73) | NR | 9.0% vs. 4.1% | 16.7% vs. 6.7% | NR |
Haugen, 2015 [ | Norway | Patients of all ages | Any surgical procedure | 5295 (2212/3083) | 19.9% vs. 12.4% | 2.2% vs. 1.5% | 1.7% vs. 0.6% | 1.6% vs. 1.0% |
Biskup, 2015 [ | New York, USA | Patients of all ages | Plastic surgery | 4476 (2166/2310) | 6.0% vs. 5.8% | NR | NR | 0.05% vs. 0.04% |
Abbreviations: NR = not reported, OR = operating room, UK = United Kingdom, USA = United States of America.
pre-implementation and 9,702 post-implementation). There were fewer returns to the OR following the implementation of the WHO surgical safety checklist (128/9,702 [1.3%] vs. 186/8,507 [2.2%]). There was significant heterogeneity between trials (p = 0.044, I2 = 45.237), and a random-effects model was assumed. Meta-analysis showed a significant reduction in the number of returns to the OR by 32.1% (RR = 0.679; 95% CI, 0.484 - 0.952; p = 0.025) (
The risk of unplanned returns to the OR was significantly reduced in both upper economic income country hospitals (RR = 0.540; 95% CI, 0.373 - 0.781; p = 0.001) and lower/middle economic income country hospitals (RR = 0.939; 95% CI, 0.557 - 1.582; p = 0.813), however, the difference between these groups was not statistically significant (p = 0.089).
Mortality data was reported in 7 trials, involving 48,517 patients (25,178 pre-implementation and 23,339 post-implementation). There were fewer deaths following the implementation of the WHO surgical safety
checklist (462/23,339 [2.0%] vs. 637/25,178 [2.5%]). There was no significant heterogeneity between trials (p = 0.228, I2 = 20.269), and a fixed-effects model was assumed. Meta-analysis showed a significant reduction in the risk of mortality by 15.3% (RR = 0.847; 95% CI, 0.752 - 0.954; p = 0.006) (
There was a greater reduction in the risk of mortality following the implementation of the WHO surgical safety checklist in lower/middle economic income country hospitals (RR = 0.722; 95% CI, 0.551 - 0.946; p =
0.018) compared to upper economic income country hospitals (RR = 0.880; 95% CI, 0.771 - 1.005; p = 0.058), however, the difference was not statistically significant (p = 0.319).
Data on the adherence to various intraoperative safety measures were reported in 4 trials, involving 12,820 patients (6254 pre-implementation and 6,566 post-implementation). Meta-analysis showed a significant increase in the adherence to most intraoperative safety measures, including the use of a pulse oximeter (RR = 1.016; 95% CI, 1.006 - 1.027; p < 0.001), use of prophylactic antibiotics when necessary (RR = 1.099; 95% CI, 1.010 - 1.195; p = 0.028), and verbally confirming the patient’s identity and site of surgery (RR = 2.716; 95% CI, 1.919 - 3.843; p < 0.001). There was also an increase in airway evaluation (RR = 1.021; 95% CI, 0.984 - 1.060; p = 0.273) and completion of a sponge count (RR = 1.009; 95% CI, 0.995 - 1.023; p = 0.207) however, this did not reach statistical significance. There was a significant decrease in ensuring the patient had adequate intravenous access (RR = 0.865; 95% CI, 0.778 - 0.963; p = 0.008) following the implementation of the WHO surgical safety checklist.
Subgroup analysis identified a significantly greater increase in adherence to various safety measures among lower/middle economic income country hospitals compared to upper economic income country hospitals. The difference was statistically significant for airway evaluation (p < 0.001), use of pulse oximeter (p < 0.001), use of prophylactic antibiotics (p = 0.024), and completion of a sponge count (p = 0.037).
All studies had moderate risk of bias and were susceptible to bias inherent to the methodology of included studies. The included studies reported on pre-implementation and post-implementation data, which does not allow for allocation concealment or blinding of participants, personnel, and outcome assessors. In many of the studies, adherence to various safety measures was determined by having an observer present during the surgery, which could lead to bias.
A funnel plot was used to qualitatively assess for publication bias, and Egger’s and Begg’s tests were done to calculate publication bias. There was no obvious evidence of asymmetry on the funnel plot (
With the rising number of surgical procedures performed and the high risk of morbidity and mortality associated with surgery, considerable attention has been placed on the prevention of adverse events and improving patient outcomes. The World Health Organization surgical safety checklist was developed in 2008 to ensure a
standardized approach to patient care with a defined set of safety standards to reinforce established safety practices and to ensure specific perioperative steps are completed in a timely manner [
The current meta-analysis found that the WHO surgical safety checklist was associated with significant risk reductions in postoperative complications, SSIs, number of unplanned returns to the OR, and overall mortality. There were also significant increases in adherence to intraoperative safety measures, including the use of a pulse oximeter, use of prophylactic antibiotics when necessary, and confirming the patient’s identity and surgical procedure and site.
The WHO surgical safety checklist proved beneficial in both upper and lower economic income country hospitals, however, there was a greater impact on lower/middle economic income hospitals as observed by greater reductions in overall complications, SSIs, and overall mortality. It has been suggested that upper economic income hospitals were already utilizing components of the checklist prior to the implementation of a formal checklist [
Substantial evidence now exists documenting the benefits of the WHO surgical safety checklist, however, the mechanism for improved patient safety is less clear and is most likely multifactorial, including improved communication among staff and the repetitive reminders to complete key perioperative steps [
Despite the significant improvements in patient safety associated with the implementation and use of the WHO surgical safety checklist, its use remains low. Vohra et al. conducted a survey of 6269 medical professionals and only 57.5% of respondents routinely used the WHO surgical safety checklist [
Several barriers to full implementation and utilization of the WHO surgical safety checklist have been recognized [
Although the results of this meta-analysis are significant, there are limitations to this study due to the variation and heterogeneity of the RCTs. The patient demographics and medical comorbidities, as well as the surgery that the patients underwent also differed between studies. Most of the studies included all surgical procedures in their study, and only one study examined each specific surgical subspecialty such as neurosurgery, plastic surgery, and orthopedic surgery, which limits the ability to perform a subgroup analysis based on the type of surgery. Biskup et al. reported no significant reduction in complications or mortality with the use of the WHO surgical safety checklist in plastic surgery, and stated that the checklist may not be as applicable to the ambulatory setting where most plastic surgery cases tend to be are performed [
Despite these limitations, this study clearly demonstrates that the WHO surgical safety checklist is an effective and valuable tool for improving patient surgical outcomes. Given the number of surgical procedures performed, the risk of morbidity and mortality associated with surgery, and the significant reductions in postoperative complications and overall mortality, the WHO surgical safety checklist should be universally implemented in all surgical centers and in all surgical patients.
All authors listed declare that there are no conflicts of interest, and have not accepted financial sponsorship in producing and presenting this article. The manuscript has been seen and approved by all members and has not been (and will not be) submitted to any other journal while it is under consideration by Surgical Science.
Christine S. M. Lau,Ronald S. Chamberlain,1 1,1 1, (2016) The World Health Organization Surgical Safety Checklist Improves Post-Operative Outcomes: A Meta-Analysis and Systematic Review. Surgical Science,07,206-217. doi: 10.4236/ss.2016.74029