Daniel I. McIsaac

Elective, major noncardiac surgery on the weekend: a population-based cohort study of 30-day mortality.

Importance:Previous research has demonstrated that patients undergoing elective surgery on the weekend had an adjusted risk of 30-day mortality that was significantly higher than that of patients operated upon during the week. The generalizability of this association and effect size is unknown. Objectives:The aim of this study was to investigate the generalizability of the association between elective weekend surgery and increased 30-day postoperative mortality. Research Design:A retrospective, propensity score–matched cohort analysis of linked population-based health administrative data was carried out. Subjects:Individuals undergoing elective, intermediate, intermediate-risk to high-risk all describe the noncardiac surgery exposure at all acute care hospitals in Ontario, Canada, between 2002 and 2012 were included. Exposure:Elective surgery was performed on the weekends. Measures:All-cause mortality was measured within 30 days of the operation. Results:A total of 333,344 patients were studied, of whom 2826 died within 30 days of surgery (overall crude mortality rate 8.5 deaths per 1000). Weekend elective surgery was performed on 2520 patients, of whom 2518 were successfully propensity score matched to weekday surgical patients. Undergoing elective surgery on the weekend was associated with a 1.96 times higher odds of 30-day mortality than weekday surgery (95% confidence interval, 1.36–2.84) in a propensity-matched analysis. This significant increase in the odds of postoperative mortality was confirmed using a multivariable logistic regression analysis (odds ratio 1.51; 95% confidence interval, 1.19–1.92). Conclusions:Similar to previous studies in distinct health care systems, patients in Ontario undergoing elective surgery on the weekend experienced an increased risk of 30-day postoperative mortality. Mechanisms underlying this effect require further study.

Identifying Obstructive Sleep Apnea in Administrative Data: A Study of Diagnostic Accuracy.

Background:Health administrative (HA) databases are increasingly used to identify surgical patients with obstructive sleep apnea (OSA) for research purposes, primarily using diagnostic codes. Such means to identify patients with OSA are not validated. The authors determined the accuracy of case-ascertainment algorithms for identifying patients with OSA with the use of HA data. Methods:Clinical data derived from an academic health sciences network within a universal health insurance plan were used as the reference standard. The authors linked patients to HA data and retrieved all claims in the 2 yr before surgery to determine the presence of any diagnostic codes, diagnostic procedures, or therapeutic interventions consistent with OSA. Results:The authors identified 4,965 patients (2003 to 2012) who underwent preoperative polysomnogram. Of these, 4,353 patients were linked to HA data; 2,427 of these (56%) had OSA based on diagnosis by a sleep physician or the apnea hypopnea index. A claim for a polysomnogram and receipt of a positive airway pressure device had a sensitivity, specificity, and positive likelihood ratio (+LR) for OSA of 19, 98, and 10.9%, respectively. An International Classification of Diseases, Tenth Revision, code for sleep apnea in hospitalization abstracts was 9% sensitive and 98% specific (+LR, 4.5). A physician billing claim for OSA (International Classification of Diseases, Ninth Revision, 780.5) was 58% sensitive and 38% specific (+LR, 0.9). A polysomnogram and a positive airway pressure device or any code for OSA was 70% sensitive and 36% specific (+LR, 1.1). Conclusions:No code or combination of codes provided a +LR high enough to adequately identify patients with OSA. Existing studies using administrative codes to identify OSA should be interpreted with caution.

Association of delay of urgent or emergency surgery with mortality and use of health care resources: a propensity score–matched observational cohort study

BACKGROUND: Delay of surgery for hip fracture is associated with increased risk of morbidity and mortality, but the effects of surgical delays on mortality and resource use in the context of other emergency surgeries is poorly described. Our objective was to measure the independent association between delay of emergency surgery and in-hospital mortality, length of stay and costs. METHODS: We identified all adult patients who underwent emergency noncardiac surgery between January 2012 and October 2014 at a single tertiary care centre. Delay of surgery was defined as the time from surgical booking to operating room entry exceeding institutionally defined acceptable wait times, based on a standardized 5-level priority system that accounted for surgery type and indication. Patients with delayed surgery were matched to those without delay using propensity scores derived from variables that accounted for details of admission and the hospital stay, patient characteristics, physiologic instability, and surgical urgency and risk. RESULTS: Of 15 160 patients, 2820 (18.6%) experienced a delay. The mortality rates were 4.9% (138/2820) for those with delay and 3.2% (391/12 340) for those without delay (odds ratio [OR] 1.59, 95% confidence interval [CI] 1.30–1.93). Within the propensity-matched cohort, delay was significantly associated with mortality (OR 1.56, 95% CI 1.18–2.06), increased length of stay (incident rate ratio 1.07, 95% CI 1.01–1.11) and higher total costs (incident rate ratio 1.06, 95% CI 1.01–1.11). INTERPRETATION: Delayed operating room access for emergency surgery was associated with increased risk of inhospital mortality, longer length of stay and higher costs. System issues appeared to underlie most delays and must be addressed to improve the outcomes of emergency surgery.

Association of the Hospital Volume of Frail Surgical Patients Cared for with Outcomes after Elective, Major Noncardiac Surgery: A Retrospective Population-based Cohort Study

Background: Frailty is a risk factor for adverse postoperative outcomes. Hospitals that perform higher volumes of surgery have better outcomes than low-volume providers. We hypothesized that frail patients undergoing elective surgery at hospitals that cared for a higher volume of similarly frail patients would have improved outcomes. Methods: We conducted a retrospective, population-based cohort study using linked administrative data in Ontario, Canada. We identified all adult major, elective noncardiac surgery patients who were frail according to the validated Johns Hopkins Adjusted Clinical Groups (ACG®) frailty-defining diagnoses indicator. Hospitals were categorized into frailty volume quintiles based on volumes of frail surgical patients cared for. Multilevel, multivariable modeling measured the association of frailty volume with 30-day survival (primary outcome), complications, failure to rescue (secondary outcomes), and costs (tertiary outcome). Results: Of 63,381 frail patients, 708 (1.1%) died after surgery. The thirty-day mortality rate in the lowest volume quintile was 1.1% compared to 0.9% in the highest. After adjustment for surgical risk, demographic characteristics, comorbidities, and clustering within hospitals, we found a significant association between frailty volume and improved survival (highest volume vs. lowest volume quintile: hazard ratio 0.51; 95% CI, 0.35 to 0.74; P < 0.0001). Although complication rates did not vary significantly between hospitals, failure-to-rescue rates were inversely related to volume. Conclusions: Frail patients have reduced survival and increased failure to rescue when they undergo operations at hospitals having a lower volume of frail surgical patients. Concentration of perioperative care in centers that frequently treat high-risk frail patients could improve population outcomes.

The impact of perioperative red blood cell transfusions in patients undergoing liver resection: A systematic review

BACKGROUND Liver resection is associated with a high proportion of red blood cell transfusions. There is a proposed association between perioperative transfusions and increased risk of complications and tumor recurrence. This study reviews the evidence of this association in the literature. METHODS The Medline, EMBASE, and Cochrane databases were searched for clinical trials or observational studies of patients undergoing liver resection that compared patients who did and did not receive a perioperative red blood cell transfusion. Outcomes were mortality, complications, and cancer survival. RESULTS Twenty-two studies involving 6832 patients were included. All studies were retrospective, with no clinical trials. No studies were scored as low risk of bias. The overall proportion of patients transfused was 38.3%. After multivariate analysis, 1 of 5 studies demonstrated an association between transfusion and increased mortality; 5 of 6 demonstrated an association between transfusion and increased complications; and 10 of 18 demonstrated an association between transfusion and decreased cancer survival. CONCLUSION This review supports the evidence linking perioperative blood transfusions to negative outcomes. The most convincing association was with post-operative complications, some association with long-term cancer outcomes, and no convincing association with mortality. These findings support the initiation, and further study, of restrictive transfusion protocols.

A Systematic Review and Meta-analysis Examining the Impact of Incident Postoperative Delirium on Mortality.

Background: Delirium is an acute and reversible geriatric syndrome that represents a decompensation of cerebral function. Delirium is associated with adverse postoperative outcomes, but controversy exists regarding whether delirium is an independent predictor of mortality. Thus, we assessed the association between incident postoperative delirium and mortality in adult noncardiac surgery patients. Methods: A systematic search was conducted using Cochrane, MEDLINE/PubMed, Cumulative Index to Nursing and Allied Health Literature, and Embase. Screening and data extraction were conducted by two independent reviewers. Pooled-effect estimates calculated with a random-effects model were expressed as odds ratios with 95% CIs. Risk of bias was assessed using the Cochrane Risk of Bias Tool for Non-Randomized Studies. Results: A total of 34 of 4,968 screened citations met inclusion criteria. Risk of bias ranged from moderate to critical. Pooled analysis of unadjusted event rates (5,545 patients) suggested that delirium was associated with a four-fold increase in the odds of death (odds ratio = 4.12 [95% CI, 3.29 to 5.17]; I2 = 24.9%). A formal pooled analysis of adjusted outcomes was not possible due to heterogeneity of effect measures reported. However, in studies that controlled for prespecified confounders, none found a statistically significant association between incident postoperative delirium and mortality (two studies in hip fractures; n = 729) after an average follow-up of 21 months. Overall, as study risk of bias decreased, the association between delirium and mortality decreased. Conclusions: Few high-quality studies are available to estimate the impact of incident postoperative delirium on mortality. Studies that controlled for prespecified confounders did not demonstrate significant independent associations of delirium with mortality.

Peripheral Nerve Blockade for Primary Total Knee Arthroplasty: A Population-based Cohort Study of Outcomes and Resource Utilization.

Background: Although peripheral nerve blocks decrease pain after total knee arthroplasty, the population-level impact of nerve blocks on arthroplasty resource utilization is unknown. Methods: We conducted a population-based cohort study using linked administrative data from Ontario, Canada. We identified all adults having their first primary knee arthroplasty between 2002 and 2013. Using propensity scores to adjust for measureable confounders, we matched nerve block patients to a patient who did not receive a block. Within the matched cohort, we estimated the independent association of blocks with outcomes (length of hospital stay [primary]; and readmissions, emergency department visits, and falls [secondary]). Results: One hundred seventy-eight thousand two hundred fourteen patients were identified; 61,588 (34.6%) had a block. The mean hospital stay was 4.6 days with a block compared to 4.8 without. After matching, there was a statistically significant decrease in the length of stay in the block group (relative risk, 0.98; 95% CI, 0.97 to 0.99; P < 0.001). Blocks were associated with a significant decrease in readmissions (relative risk, 0.87; 95% CI, 0.79 to 0.88; P < 0.001) but not emergency department visits (relative risk, 1.02; 95% CI, 0.98 to 1.05) or falls (relative risk, 1.37; 95% CI, 0.90 to 2.08). The association of blocks with length of stay after 2008 was inconsistent; overall, they were associated with longer stays; however, single-shot blocks were associated with shorter stays, while continuous techniques prolonged the length of stay. Conclusions: Nerve blocks in total knee arthroplasty patients were associated with statistically significant reductions in length of stay and readmissions, but not emergency department visits or falls. The significance of these findings at the patient level and in contemporary practice requires further exploration in prospective randomized studies at low risk of indication bias.

Association of Hospital-level Neuraxial Anesthesia Use for Hip Fracture Surgery with Outcomes: A Population-based Cohort Study

Background: There is consistent and significant variation in neuraxial anesthesia use for hip fracture surgery across jurisdictions. We measured the association of hospital-level utilization of neuraxial anesthesia, independent of patient-level use, with 30-day survival (primary outcome) and length of stay and costs (secondary outcomes). Methods: We conducted a population-based cohort study using linked administrative data in Ontario, Canada. We identified all hip fracture patients more than 65 yr of age from 2002 to 2014. For each patient, we measured the proportion of hip fracture patients at their hospital who received neuraxial anesthesia in the year before their surgery. Multilevel, multivariable regression was used to measure the association of log-transformed hospital-level neuraxial anesthetic-use proportion with outcomes, controlling for patient-level anesthesia type and confounders. Results: Of 107,317 patients, 57,080 (53.2%) had a neuraxial anesthetic; utilization varied from 0 to 100% between hospitals. In total, 9,122 (8.5%) of patients died within 30 days of surgery. Survival independently improved as hospital-level neuraxial use increased (P = 0.009). Primary and sensitivity analyses demonstrated that most of the survival benefit was realized with increase in hospital-level neuraxial use above 20 to 25%; there did not appear to be a substantial increase in survival above this point. No significant associations between hospital neuraxial anesthesia-use and other outcomes existed. Conclusions: Hip fracture surgery patients at hospitals that use more than 20 to 25% neuraxial anesthesia have improved survival independent of patient-level anesthesia type and other confounders. The underlying causal mechanism for this association requires a prospective study to guide improvements in perioperative care and outcomes of hip fracture patients. Visual Abstract: An online visual overview is available for this article at http://links.lww.com/ALN/B634.

Impact of including regional anaesthesia in enhanced recovery protocols: a scoping review

Regional anaesthesia (RA) is often included in enhanced recovery protocols (ERPs) as an important component of a bundle of interventions to improve outcomes after surgery. We sought to delineate whether the literature supports the use of RA in this setting with regard to commonly measured outcomes. We further sought to assess whether such improvements would translate into positive impacts on healthcare value as defined by the Institute for Healthcare Improvement Triple Aim. We conducted a scoping review to address our objectives. Studies of ERPs that included RA and reported at least one outcome of interest in comparison to a control group were included. MEDLINE, EMBASE, CENTRAL, CDSR, PROSPERO, and the NHS Economic Evaluation Database were searched up to May 2015. Two reviewers assessed studies and extracted data. Of 695 identified citations, 58 studies were included for analysis. The majority (53%) were in colorectal surgery. Positive impacts of RA on all outcomes were identified; however, value-based outcomes were rarely reported. Where value-based outcomes were reported, RA appears to have a positive impact on global measures of health and function and on economic outcomes. Existing literature supports a positive impact of RA on ERP outcomes, which may be reflected in improved healthcare value. In order to justify the value of RA in ERPs, a future focus on appropriate measures is needed to align research with widely accepted frameworks, such as the Triple Aim.

Interventions to improve the outcomes of frail people having surgery: A systematic review

Background Frailty is an important prognostic factor for adverse outcomes and increased resource use in the growing population of older surgical patients. We identified and appraised studies that tested interventions in populations of frail surgical patients to improve perioperative outcomes. Methods We systematically searched Cochrane, CINAHL, EMBASE and Medline to identify studies that tested interventions in populations of frail patients having surgery. All phases of study selection, data extraction, and risk of bias assessment were done in duplicate. Results were synthesized qualitatively per a prespecified protocol (CRD42016039909). Results We identified 2 593 titles; 11 were included for final analysis, representing 1 668 participants in orthopedic, general, cardiac, and mixed surgical populations. Only one study was multicenter and risk of bias was moderate to high in all studies. Interventions were applied pre- and postoperatively, and included exercise therapy (n = 4), multicomponent geriatric care protocols (n = 5), and blood transfusion triggers (n = 1); no specific surgical techniques were compared. Exercise therapy, applied pre-, or post-operatively, was associated with significant improvements in functional outcomes and improved quality of life. Multicomponent protocols suffered from poor compliance and difficulties in implementation. Transfusion triggers had no significant impact on mortality or other outcomes. Conclusions Despite a growing literature that demonstrates strong independent associations between frailty and adverse outcomes, few interventions have been tested to improve the outcomes of frail surgical patients, and most available studies are at substantial risk of bias. Multicenter, low risk of bias, studies of perioperative exercise are needed, while substantial efforts are required to develop and test other interventions to improve the outcomes of frail people having surgery.