Perioperative medicine training resources: U2M14: Perioperative care protocols

Abstract
Background: Poor functional capacity has been identified as an important modifiable risk factor for postoperative complications. Cardiopulmonary exercise testing (CPET) provides objective parameters of functional capacity (e.g., oxygen consumption at peak exercise, peak VO2), with significant prognostication for postoperative complications. However, sex-specific thresholds for functional capacity to predict surgical risk are yet to be established. Therefore, we performed a post hoc analysis of the international, multicentre, prospective observational METS (Measurement of Exercise Tolerance before Surgery) study to evaluate if sex-specific thresholds of peak VO2 improve risk prediction of postoperative complications.

Methods: We undertook a post hoc analysis (HREC/71824/PMCC) of the METS study, which was performed between March 2013 and March 2016. We investigated whether sex-specific differences exist for CPET-derived parameters and associated thresholds for predicting postoperative complications in this large cohort of patients that had major non-cardiac surgery (n = 1266). Logistic regression models were analyzed for the association of low peak VO2 with moderate-to-severe in-hospital postoperative complications. Optimal sex-specific peak VO2 thresholds were obtained by maximizing the Youden index of receiver operating characteristic (ROC) curves. Finally, multivariable logistic regression models tested the resulting sex-specific thresholds against the established non-sex-specific peak VO2 threshold (14 mL kg-1 min-1) adjusted for clinically relevant features such as comorbidities and surgical complexity. Models were evaluated by bootstrapping optimism-corrected area under the ROC curve and the net reclassification improvement index (NRI).

Findings: Female patients (n = 480) had a lower mean (SD) peak VO2 than males (16.7 (4.9) mL kg-1 min-1 versus 21.2 (6.5) mL kg-1 min-1, p < 0.001) and a lower postoperative complication rate (10.4% versus 15.3%; p = 0.018) than males (n = 786). The optimal peak VO2 threshold for predicting postoperative complications was 12.4 mL kg-1 min-1 for females and 22.3 mL kg-1 min-1 for males, respectively. In the multivariable regression model, low non-sex-specific peak VO2 did not independently predict postoperative complications. In contrast, low sex-specific peak VO2 was an independent predictor of postoperative complications (OR 2.29; 95% CI: 1.60, 3.30; p < 0.001). The optimism-corrected AUC-ROC of the sex-specific model was higher compared with the non-sex-specific model (0.73 versus 0.7; DeLong's test: p = 0.021). The sex-specific model classified 39% of the patients more correctly than the baseline model (NRI = 0.39; 95% CI: 0.24, 0.55). In contrast, the non-sex-specific model only classified 9% of the patients more correctly when compared against the baseline model (NRI = 0.09; 95% CI: -0.04, 0.22).

Interpretation: Our data report sex-specific differences in preoperative CPET-derived functional capacity parameters. Sex-specific peak VO2 thresholds identify patients at increased risk for postoperative complications with a higher discriminatory ability than a sex-unspecific threshold. As such, sex-specific threshold values should be considered in preoperative CPET to potentially improve risk stratification and to guide surgical decision-making, including eligibility for surgery, preoperative optimization strategies (prehabilitation) or seeking non-surgical options.

Funding: There was no funding for the present study. The original METS study was funded by Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, Ontario Ministry of Health and Long-Term Care, Ontario Ministry of Research, Innovation and Science, UK National Institute of Academic Anaesthesia, UK Clinical Research Collaboration, Australian and New Zealand College of Anaesthetists, and Monash University.

Abstract
The European Working Group on Sarcopenia in Older People (EWGSOP) developed a practical clinical definition and consensus diagnostic criteria for age-related sarcopenia. EWGSOP included representatives from four participant organisations, i.e. the European Geriatric Medicine Society, the European Society for Clinical Nutrition and Metabolism, the International Association of Gerontology and Geriatrics-European Region and the International Association of Nutrition and Aging. These organisations endorsed the findings in the final document. The group met and addressed the following questions, using the medical literature to build evidence-based answers: (i) What is sarcopenia? (ii) What parameters define sarcopenia? (iii) What variables reflect these parameters, and what measurement tools and cut-off points can be used? (iv) How does sarcopenia relate to cachexia, frailty and sarcopenic obesity? For the diagnosis of sarcopenia, EWGSOP recommends using the presence of both low muscle mass + low muscle function (strength or performance). EWGSOP variously applies these characteristics to further define conceptual stages as 'presarcopenia', 'sarcopenia' and 'severe sarcopenia'. EWGSOP reviewed a wide range of tools that can be used to measure the specific variables of muscle mass, muscle strength and physical performance. Our paper summarises currently available data defining sarcopenia cut-off points by age and gender; suggests an algorithm for sarcopenia case finding in older individuals based on measurements of gait speed, grip strength and muscle mass; and presents a list of suggested primary and secondary outcome domains for research. Once an operational definition of sarcopenia is adopted and included in the mainstream of comprehensive geriatric assessment, the next steps are to define the natural course of sarcopenia and to develop and define effective treatment.

Abstract
Background: Risky consumption of alcohol is a global problem. More than 3.3 million deaths annually are associated with risky use of alcohol, and global alcohol consumption continues to increase. People who have high alcohol consumption often require planned and emergency surgical procedures.Risky drinking is associated with increased postoperative complications such as infections, cardiopulmonary complications, and bleeding episodes. Alcohol causes disorders of the liver, pancreas, and nervous system. Stopping consumption of alcohol can normalize these organ systems to some degree and may reduce the occurrence of complications after surgery.This review was first published in 2012 and was updated in 2018.

Objectives: To assess the effects of perioperative alcohol cessation interventions on rates of postoperative complications and alcohol consumption.

Search methods: We searched the following databases up until 21 September 2018: Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library; MEDLINE; Embase; CINAHL via EBSCOhost; and two trials registers. We scanned the reference lists and citations of included trials and any identified relevant systematic reviews for further references to additional trials. When necessary, we contacted trial authors to ask for additional information.

Selection criteria: We included all randomized controlled trials (RCTs) that evaluated the effects of perioperative alcohol cessation interventions on postoperative complications and alcohol consumption. We included participants with risky consumption of alcohol who were undergoing all types of elective or acute surgical procedures under general or regional anaesthesia or sedation, who were offered a perioperative alcohol cessation intervention or no intervention.We defined 'risky drinking' as alcohol consumption equivalent to more than 3 alcoholic units (AU)/d or 21 AU/week (with 1 AU containing 12 grams of ethanol) with or without symptoms of alcohol abuse or dependency. This corresponds to the amount of alcohol associated with increased postoperative complication rates in most clinical studies.

Data collection and analysis: We used guidance provided in the Cochrane Handbook for Systematic Reviews of Interventions. We presented main outcomes as dichotomous variables in a meta-analysis. When data were available, we conducted subgroup and sensitivity analyses to explore the risk of bias. Primary outcome measures were postoperative complications and in-hospital and 30-day mortality. Secondary outcomes were successful quitting at the end of the programme, postoperative alcohol use, and length of hospital stay. We assessed the quality of evidence using the GRADE approach.

Main results: We included in this updated review one new study (70 participants), resulting in a total of three RCTs (140 participants who drank 3 to 40 AU/d). All three studies were of moderate to good quality. All studies evaluated the effects of intensive alcohol cessation interventions, including pharmacological strategies for alcohol withdrawal symptoms, patient education, and relapse prophylaxis. We identified one ongoing study.Overall, 53 of the 122 participants from three studies who underwent surgery developed any type of postoperative complication that required treatment. Of 61 participants in the intervention groups, 20 had complications, compared with 33 of 61 participants in the control groups (risk ratio (RR) 0.62, 95% confidence interval (CI) 0.40 to 0.96). Results show differences between the three clinical studies regarding outcome measurement and intensity of the interventions. However, all alcohol cessation programmes were intensive and included pharmacological therapy. The overall quality of evidence for this outcome is moderate.In-hospital and 30-day postoperative mortality rates were low in the three studies. Researchers reported one death among 61 participants in the intervention groups, and three deaths among 61 participants in the control groups (RR 0.47, 95% CI 0.07 to 2.96). The quality of evidence for this outcome is low.Investigators describe more successful quitters at the end of the intervention programme than among controls. Forty-one out of 70 participants in the intervention groups successfully quit drinking compared with only five out of 70 participants in the control groups (RR 8.22, 95% CI 1.67 to 40.44). The quality of evidence for this outcome is moderate.All three studies reported postoperative alcohol consumption (grams of alcohol/week) at the end of the programme as median and range values; therefore it was not possible to estimate the mean and the standard deviation (SD). We performed no meta-analysis. All three studies reported length of stay, and none of these studies described a significant difference in length of stay. Data were insufficient for review authors to perform a meta-analysis. No studies reported on the prevalence of participants without risky drinking in the longer term.

Authors' conclusions: This systematic review assessed the efficacy of perioperative alcohol cessation interventions for postoperative complications and alcohol consumption. All three studies showed a significant reduction in the number of participants who quit drinking alcohol during the intervention period. Intensive alcohol cessation interventions offered for four to eight weeks to participants undergoing all types of surgical procedures to achieve complete alcohol cessation before surgery probably reduced the number of postoperative complications. Data were insufficient for review authors to assess their effects on postoperative mortality. No studies reported an effect on length of stay, and no studies addressed the prevalence of risky drinking in the longer term.Included studies were few and reported small sample sizes; therefore one should be careful about drawing firm conclusions based on these study results. All three studies were conducted in Denmark, and most participants were men. The included participants may represent a selective group, as they could have been more motivated and/or more interested in participating in clinical research or otherwise different, and effects may have been overestimated for both intervention and control groups in these studies. Trial results indicate that these studies are difficult to perform, that strong research competencies are necessary for future studies, and that further evaluation of perioperative alcohol cessation interventions in high-quality randomized controlled trials is needed. Once published and assessed, the one 'ongoing' study identified may alter the conclusions of this review.

Abstract
Background: Enhanced recovery after surgery (ERAS) programs are multimodal care pathways designed to minimize the physiological and psychological impact of surgery for patients. Increased compliance with ERAS guidelines is associated with improved patient outcomes across surgical types. As ERAS programs have proliferated, an unintentional effect has been significant variation in how ERAS-related studies are reported in the literature.

Methods: To improve the quality of ERAS reporting, ERAS® USA and the ERAS® Society launched an effort to create an instrument to assist authors in manuscript preparation. Criteria to include were selected by a combination of literature review and expert opinion. The final checklist was refined by group consensus.

Results: The Societies present the Reporting on ERAS Compliance, Outcomes, and Elements Research (RECOvER) Checklist. The tool contains 20 items including best practices for reporting clinical pathways, compliance auditing, and formatting guidelines.

Conclusions: The RECOvER Checklist is intended to provide a standardized framework for the reporting of ERAS-related studies. The checklist can also assist reviewers in evaluating the quality of ERAS-related manuscripts. Authors are encouraged to include the RECOvER Checklist when submitting ERAS-related studies to peer-reviewed journals.

Abstract
Background: Group education is increasing in popularity as a means of preparing patients for surgery. In recent years, these 'surgery schools' have evolved from primarily informing patients of what to expect before and after surgery, to providing support and encouragement for patients to 'prehabilitate' prior to surgery, through improving physical fitness, nutrition and emotional wellbeing.

Method: A survey aimed at clinicians delivering surgery schools was employed to capture a national overview of activity to establish research and practice priorities in this area. The survey was circulated online via the Enhanced Recovery after Surgery UK Society and the Centre for Perioperative Care mailing lists as well as social media.

Results: There were 80 responses describing 28 active and 4 planned surgery schools across the UK and Ireland. Schools were designed and delivered by multidisciplinary teams, contained broadly similar content and were well attended. Most were funded by the National Health Service. The majority included aspects of prehabilitation most commonly the importance of physical fitness. Seventy five percent of teams collected patient outcome data, but less than half collected data to establish the clinical effectiveness of the school. Few describe explicit inclusion of evidence-based behavior change techniques, but collaboration and partnerships with community teams, gyms and local charities were considered important in supporting patients to make changes in health behaviors prior to surgery.

Conclusion: It is recommended that teams work with patients when designing surgery schools and use evidence-based behavior change frameworks and techniques to inform their content. There is a need for high-quality research studies to determine the clinical effectiveness of this type of education intervention.

Abstract
The stress response to surgery, critical illness, trauma, and burns encompasses derangements of metabolic and physiological processes that induce perturbations in the inflammatory, acute phase, hormonal, and genomic responses. Hypermetabolism and hypercatabolism result, leading to muscle wasting, impaired immune function and wound healing, organ failure, and death. The surgery-induced stress response is largely similar to that triggered by traumatic injuries; the duration of the stress response, however, varies according to the severity of injury (surgical or traumatic). This spectrum of injuries and insults ranges from small lacerations to severe insults such as large poly-traumatic and burn injuries. Burn injuries provide an extreme model of trauma induced stress responses that can be used to study the long-term effects of a prolonged stress response. Although the stress response to acute trauma evolved to confer improved chances of survival following injury, in modern surgical practice the stress response can be detrimental.

Keywords: ACC/AHA Clinical Practice Guideline; adrenergic beta-antagonists; anesthesia and analgesia; cardiovascular; diagnostic techniques; intraoperative; monitoring; perioperative care; platelet aggregation inhibitors; referral and consultation; troponin.

Abstract
This narrative review presents a biological rationale and evidence to describe how the preoperative condition of the patient contributes to postoperative morbidity. Any preoperative condition that prevents a patient from tolerating the physiological stress of surgery (e.g. poor cardiopulmonary reserve, sarcopaenia), impairs the stress response (e.g. malnutrition, frailty), and/or augments the catabolic response to stress (e.g. insulin resistance) is a risk factor for poor surgical outcomes. Prehabilitation interventions that include exercise, nutrition, and psychosocial components can be applied before surgery to strengthen physiological reserve and enhance functional capacity, which, in turn, supports recovery through attaining surgical resilience. Prehabilitation complements Enhanced Recovery After Surgery (ERAS) care to achieve optimal patient outcomes because recovery is not a passive process and it begins preoperatively.

Abstract
Preoperative malnutrition because of poor oral intake significantly increases the risk of adverse events after surgery and leads to increased length of stay. While immunonutrition has been utilized in the non-ERAS setting, its utility in both minimally invasive surgery and ERAS pathway procedures remain poorly defined. There are at least ten meta-analyses regarding the assessment of immunonutrition, but virtually, all of these were performed in an era prior to minimally invasive surgery, adoption of enhanced recovery protocols, and an understanding of the assessment and physiology of sarcopenia. In terms of immunonutrition within an ERAS pathway, the few studies that have been published have severe flaws in design and sample, bringing their overall conclusion into question. Furthermore, the optimal components of immunonutrition have yet to be adequately determined and may vary for patients based on comorbidities as well as the proposed procedures. Risk stratification based on markers of nutritionally deficient states such as image assessed sarcopenia, Glasgow Prognostic Score, prognostic nutrition index, or assessment of methylarginines are needed prior to the initiation of any such immunotherapy. Lastly, there is a need for properly designed randomized control trials that stratify patients appropriately and determine the optimal timing, composition, and duration of immunotherapy.

Abstract
Tobacco smoking is associated with a substantially increased risk of postoperative complications. The peri-operative period offers a unique opportunity to support patients to stop tobacco smoking, avoid complications and improve long-term health. This systematic review provides an up-to-date summary of the evidence for tobacco cessation interventions in surgical patients. We conducted a systematic search of randomised controlled trials of tobacco cessation interventions in the peri-operative period. Quantitative synthesis of the abstinence outcomes data was by random-effects meta-analysis. The primary outcome of the meta-analysis was abstinence at the time of surgery, and the secondary outcome was abstinence at 12 months. Thirty-eight studies are included in the review (7310 randomised participants) and 26 studies are included in the meta-analysis (5969 randomised participants). Studies were pooled for subgroup analysis in two ways: by the timing of intervention delivery within the peri-operative period and by the intensity of the intervention protocol. We judged the quality of evidence as moderate, reflecting the degree of heterogeneity and the high risk of bias. Overall, peri-operative tobacco cessation interventions increased successful abstinence both at the time of surgery, risk ratio (95%CI) 1.48 (1.20-1.83), number needed to treat 7; and 12 months after surgery, risk ratio (95%CI) 1.62 (1.29-2.03), number needed to treat 9. More work is needed to inform the design and optimal delivery of interventions that are acceptable to patients and that can be incorporated into contemporary elective and urgent surgical pathways. Future trials should use standardised outcome measures.

Abstract
Shared decision making requires a shift in attitudes at all levels but can become part of routine practice with the right support, say Natalie Joseph-Williams and colleagues

Abstract
Importance: Enhanced Recovery After Surgery (ERAS) is a paradigm shift in perioperative care, resulting in substantial improvements in clinical outcomes and cost savings.

Observations: Enhanced Recovery After Surgery is a multimodal, multidisciplinary approach to the care of the surgical patient. Enhanced Recovery After Surgery process implementation involves a team consisting of surgeons, anesthetists, an ERAS coordinator (often a nurse or a physician assistant), and staff from units that care for the surgical patient. The care protocol is based on published evidence. The ERAS Society, an international nonprofit professional society that promotes, develops, and implements ERAS programs, publishes updated guidelines for many operations, such as evidence-based modern care changes from overnight fasting to carbohydrate drinks 2 hours before surgery, minimally invasive approaches instead of large incisions, management of fluids to seek balance rather than large volumes of intravenous fluids, avoidance of or early removal of drains and tubes, early mobilization, and serving of drinks and food the day of the operation. Enhanced Recovery After Surgery protocols have resulted in shorter length of hospital stay by 30% to 50% and similar reductions in complications, while readmissions and costs are reduced. The elements of the protocol reduce the stress of the operation to retain anabolic homeostasis. The ERAS Society conducts structured implementation programs that are currently in use in more than 20 countries. Local ERAS teams from hospitals are trained to implement ERAS processes. Audit of process compliance and patient outcomes are important features. Enhanced Recovery After Surgery started mainly with colorectal surgery but has been shown to improve outcomes in almost all major surgical specialties.

Conclusions and relevance: Enhanced Recovery After Surgery is an evidence-based care improvement process for surgical patients. Implementation of ERAS programs results in major improvements in clinical outcomes and cost, making ERAS an important example of value-based care applied to surgery.

Abstract
Background: Single-centre studies have suggested that enhanced recovery can be achieved with multimodal perioperative care protocols. This international observational study evaluated the implementation of an enhanced recovery programme in five European centres and examined the determinants affecting recovery and length of hospital stay.

Methods: Four hundred and twenty-five consecutive patients undergoing elective open colorectal resection above the peritoneal reflection between January 2001 and January 2004 were enrolled in a protocol that defined multiple perioperative care elements. One centre had been developing multimodal perioperative care for 10 years, whereas the other four had previously undertaken traditional care.

Results: The case mix was similar between centres. Protocol compliance before and during the surgical procedure was high, but it was low in the immediate postoperative phase. Patients fulfilled predetermined recovery criteria a median of 3 days after operation but were actually discharged a median of 5 days after surgery. Delay in discharge and the development of major complications prolonged length of stay. Previous experience with fast-track surgery was associated with a shorter hospital stay.

Conclusion: Functional recovery in 3 days after colorectal resection could be achieved in daily practice. A protocol is not enough to enable discharge of patients on the day of functional recovery; more experience and better organization of care may be required.

Abstract
Postoperative pulmonary complications (PPCs) are common, costly, and increase patient mortality. Changes to the respiratory system occur immediately on induction of general anaesthesia: respiratory drive and muscle function are altered, lung volumes reduced, and atelectasis develops in > 75% of patients receiving a neuromuscular blocking drug. The respiratory system may take 6 weeks to return to its preoperative state after general anaesthesia for major surgery. Risk factors for PPC development are numerous, and clinicians should be aware of non-modifiable and modifiable factors in order to recognize those at risk and optimize their care. Many validated risk prediction models are described. These have been useful for improving our understanding of PPC development, but there remains inadequate consensus for them to be useful clinically. Preventative measures include preoperative optimization of co-morbidities, smoking cessation, and correction of anaemia, in addition to intraoperative protective ventilation strategies and appropriate management of neuromuscular blocking drugs. Protective ventilation includes low tidal volumes, which must be calculated according to the patient's ideal body weight. Further evidence for the most beneficial level of PEEP is required, and on-going randomized trials will hopefully provide more information. When PEEP is used, it may be useful to precede this with a recruitment manoeuvre if atelectasis is suspected. For high-risk patients, surgical time should be minimized. After surgery, nasogastric tubes should be avoided and analgesia optimized. A postoperative mobilization, chest physiotherapy, and oral hygiene bundle reduces PPCs.

Abstract
Enhanced recovery after surgery (ERAS) protocols are a combination of multimodal evidence-based strategies, applied to the conventional perioperative techniques, to reduce postoperative complications and to achieve early recovery. These strategies or protocols, require a dedicated and organized team effort for their implementation to enable early discharge and thus reduce the length of hospital stay. Anesthesiologists play an important role in facilitating these protocols as some of the key elements such as preoperative patient preparation and assessment, perioperative fluid management, and perioperative pain relief are handled by them. This article discusses in detail the various components of ERAS and the anesthesiologist's role in implementing them.

Abstract
Risk stratification is essential for both clinical risk prediction and comparative audit. There are a variety of risk stratification tools available for use in major noncardiac surgery, but their discrimination and calibration have not previously been systematically reviewed in heterogeneous patient cohorts.Embase, MEDLINE, and Web of Science were searched for studies published between January 1, 1980 and August 6, 2011 in adult patients undergoing major noncardiac, nonneurological surgery. Twenty-seven studies evaluating 34 risk stratification tools were identified which met inclusion criteria. The Portsmouth-Physiology and Operative Severity Score for the enUmeration of Mortality and the Surgical Risk Scale were demonstrated to be the most consistently accurate tools that have been validated in multiple studies; however, both have limitations. Future work should focus on further evaluation of these and other parsimonious risk predictors, including validation in international cohorts. There is also a need for studies examining the impact that the use of these tools has on clinical decision making and patient outcome.

Abstract
A randomized, blind and prospective clinical trial was conducted to compare two clinical rehabilitation protocols in patients submitted to orthognathic surgery, during the first 60 days after surgery. Pain, edema, mandibular movement, masticatory efficiency and quality of life were evaluated. Nineteen (19) patients were separated into control and experimental groups. The control group consisted of 10 patients followed by oral and maxillofacial surgeons and submitted to a rehabilitation protocol that involved active and passive mouth opening exercises. The experimental group had 9 patients and followed the surgeons' protocol, in addition to an Early Recovery After Surgery (ERAS) protocol performed by speech therapists, and involving specific motricity exercises and lymphatic drainage. The Student's t-test was applied to compare the results, and the Fisher's exact test of independence, to analyze the quality of life and the masticatory efficiency variables. The statistical significance was set at 5% (p < 0.05) for all the tests. The results showed that the ERAS protocol made a positive difference in pain perception in the first 14 days. However, it did not improve the other variables. Although many variables showed no significant difference, it was concluded that the surgeons can delegate patient rehabilitation to qualified professionals, so that they can optimize their postoperative clinical time.

Abstract
Background: Enhanced Recovery After Surgery (ERAS) protocols reduce length of stay, complications and costs for a large number of elective surgical procedures. A similar, structured approach appears to improve outcomes, including mortality, for patients undergoing high-risk emergency general surgery, and specifically emergency laparotomy. These are the first consensus guidelines for optimal care of these patients using an ERAS approach.

Methods: Experts in aspects of management of the high-risk and emergency general surgical patient were invited to contribute by the International ERAS® Society. Pubmed, Cochrane, Embase, and MEDLINE database searches on English language publications were performed for ERAS elements and relevant specific topics. Studies on each item were selected with particular attention to randomized controlled trials, systematic reviews, meta-analyses and large cohort studies, and reviewed and graded using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. Recommendations were made on the best level of evidence, or extrapolation from studies on non-emergency patients when appropriate. The Delphi method was used to validate final recommendations. The guideline has been divided into two parts: Part 1-Preoperative Care and Part 2-Intraoperative and Postoperative management. This paper provides guidelines for Part 1.

Results: Twelve components of preoperative care were considered. Consensus was reached after three rounds.

Conclusions: These guidelines are based on the best available evidence for an ERAS approach to patients undergoing emergency laparotomy. Initial management is particularly important for patients with sepsis and physiological derangement. These guidelines should be used to improve outcomes for these high-risk patients.

Abstract
Background: Previous studies, which relied on hypothetical cases and chart reviews, have questioned the inter-rater reliability of the ASA physical status (ASA-PS) scale. We therefore conducted a retrospective cohort study to evaluate its inter-rater reliability and validity in clinical practice.

Methods: The cohort included all adult patients (≥18 yr) who underwent elective non-cardiac surgery at a quaternary-care teaching institution in Toronto, Ontario, Canada, from March 2010 to December 2011. We assessed inter-rater reliability by comparing ASA-PS scores assigned at the preoperative assessment clinic vs the operating theatre. We also assessed the validity of the ASA-PS scale by measuring its association with patients' preoperative characteristics and postoperative outcomes.

Results: The cohort included 10 864 patients, of whom 5.5% were classified as ASA I, 42.0% as ASA II, 46.7% as ASA III, and 5.8% as ASA IV. The ASA-PS score had moderate inter-rater reliability (κ 0.61), with 67.0% of patients (n=7279) being assigned to the same ASA-PS class in the clinic and operating theatre, and 98.6% (n=10 712) of paired assessments being within one class of each other. The ASA-PS scale was correlated with patients' age (Spearman's ρ, 0.23), Charlson comorbidity index (ρ=0.24), revised cardiac risk index (ρ=0.40), and hospital length of stay (ρ=0.16). It had moderate ability to predict in-hospital mortality (receiver-operating characteristic curve area 0.69) and cardiac complications (receiver-operating characteristic curve area 0.70).

Conclusions: Consistent with its inherent subjectivity, the ASA-PS scale has moderate inter-rater reliability in clinical practice. It also demonstrates validity as a marker of patients' preoperative health status.

Abstract
Background: Preoperative alteration of T cell-mediated immunity as well as an altered immune response to surgical stress were found in long-term alcoholic patients. The aim of this study was to evaluate perioperative T cell-mediated immune parameters as well as cytokine release from whole blood cells after lipopolysaccharide stimulation and its association with postoperative infections.

Methods: Fifty-four patients undergoing elective surgery of the aerodigestive tract were included in this prospective observational study. Long-term alcoholic patients (n = 31) were defined as having a daily ethanol consumption of at least 60 g and fulfilling the Diagnostic and Statistical Manual of Mental Disorders for either alcohol abuse or alcohol dependence. The nonalcoholic patients (n = 23) were defined as drinking less than 60 g ethanol/day. Blood samples to analyze the immune status were obtained on morning before surgery and on the morning of days 1, 3, and 5 after surgery.

Results: Basic patient characteristics did not differ between groups. Before surgery, the T helper 1:T helper 2 ratio (Th1: Th2) was significantly lower (P < 0.01), whereas plasma interleukin 1beta and lipopolysaccharide-stimulated interleukin 1ra from whole blood cells were increased in long-term alcoholic patients. After surgery, a significant suppression of the cytotoxic lymphocyte ratio (Tc1:Tc2), the interferon gamma:interleukin 10 ratio from lipopolysaccharide-stimulated whole blood cells, and a significant increase of plasma interleukin 10 was observed. Long-term alcoholics had more frequent postoperative infections compared with nonalcoholic patients (54%vs. 26%; P = 0.03).

Conclusions: T helper cell-mediated immunity was significantly suppressed before surgery and possibly led to inadequate cytotoxic lymphocyte and whole blood cell response in long-term alcoholic patients after surgery. This altered cell-mediated immunity might have accounted for the increased infection rate in long-term alcoholic patients after surgery.

Abstract
Backgrounds: There is mixed evidence on the value of preoperative cardiorespiratory exercise test (CPET) to predict postoperative outcomes in patients undergoing a cancer surgical procedure. The purpose of this review was to investigate the association between preoperative CPET variables and postoperative complications, length of hospital stay, and quality of life in patients undergoing cancer surgery.

Methods: A search was conducted on MEDLINE, Embase, AMED, and Web of science from inception to April 2020. Cohort studies investigating the association between preoperative CPET variables, including peak oxygen uptake (peak VO2), anaerobic threshold (AT), or ventilatory equivalent for carbon dioxide (VE/VCO2), and postoperative outcomes (complications, length of stay, and quality of life) were included. Risk of bias was assessed using the QUIPS tool. A random-effect model meta-analysis was performed whenever possible.

Results: Fifty-two unique studies, including 10,030 patients were included. Overall, most studies were rated as having low risk of bias. Higher preoperative peak VO2 was associated with absence of postoperative complications (mean difference [MD]: 2.28; 95% confidence interval [CI]: 1.26-3.29) and no pulmonary complication (MD: 1.47; 95% CI: 0.49-2.45). Preoperative AT and VE/VCO2 also demonstrated some positive trends. None of the included studies reported a negative trend.

Conclusions: This systematic review and meta-analysis demonstrated a significant association between superior preoperative CPET values, especially peak VO2, and better postoperative outcomes. The assessment of preoperative functional capacity in patients undergoing cancer surgery has the potential to facilitate treatment decision making.

Abstract
Background: The use of preoperative cardiopulmonary exercise testing (CPET) to evaluate the risk of adverse perioperative outcomes is increasingly prevalent. CPET-derived information enables personalised perioperative care and enhances shared decision-making. Sex-related differences in physical fitness are reported in non-perioperative literature. However, little attention has been paid to sex-related differences in the context of perioperative CPET.

Aim: We explored differences in the physical fitness variables reported in a recently published multi-centre study investigating CPET before colorectal surgery. We also report the inclusion rate of females in published perioperative CPET cohorts that are shaping guidelines and clinical practice.

Methods: We performed a post hoc analysis of the trial data of 703 patients who underwent CPET prior to major elective colorectal surgery. We also summarised the female inclusion rate in peer-reviewed published reports of perioperative CPET.

Results: Fitness assessed using commonly used perioperative CPET variables-oxygen consumption at anaerobic threshold (AT) and peak exercise-was significantly higher in males than in females both before and after correction for body weight. In studies contributing to the development of perioperative CPET, 68.5% of the participants were male.

Conclusion: To our knowledge, this is the first study to describe differences between males and females in CPET variables used in a perioperative setting. Furthermore, there is a substantial difference between the inclusion rates of males and females in this field. These findings require validation in larger cohorts and may have significant implications for both sexes in the application of CPET in the perioperative setting.

Abstract
Background: Smokers have a substantially increased risk of postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence, and surgery may constitute a unique opportunity for smoking cessation interventions.

Objectives: The objectives of this review are to assess the effect of preoperative smoking intervention on smoking cessation at the time of surgery and 12 months postoperatively, and on the incidence of postoperative complications.

Search methods: We searched the Cochrane Tobacco Addiction Group Specialized Register in January 2014.

Selection criteria: Randomized controlled trials that recruited people who smoked prior to surgery, offered a smoking cessation intervention, and measured preoperative and long-term abstinence from smoking or the incidence of postoperative complications or both outcomes.

Data collection and analysis: The review authors independently assessed studies to determine eligibility, and discussed the results between them.

Main results: Thirteen trials enrolling 2010 participants met the inclusion criteria. One trial did not report cessation as an outcome. Seven reported some measure of postoperative morbidity. Most studies were judged to be at low risk of bias but the overall quality of evidence was moderate due to the small number of studies contributing to each comparison.Ten trials evaluated the effect of behavioural support on cessation at the time of surgery; nicotine replacement therapy (NRT) was offered or recommended to some or all participants in eight of these. Two trials initiated multisession face-to-face counselling at least four weeks before surgery and were classified as intensive interventions, whilst seven used a brief intervention. One further study provided an intensive intervention to both groups, with the intervention group additionally receiving a computer-based scheduled reduced smoking intervention. One placebo-controlled trial examined the effect of varenicline administered one week preoperatively followed by 11 weeks postoperative treatment, and one placebo-controlled trial examined the effect of nicotine lozenges from the night before surgery as an adjunct to brief counselling at the preoperative evaluation. There was evidence of heterogeneity between the effects of trials using intensive and brief interventions, so we pooled these separately. An effect on cessation at the time of surgery was apparent in both subgroups, but the effect was larger for intensive intervention (pooled risk ratio (RR) 10.76; 95% confidence interval (CI) 4.55 to 25.46, two trials, 210 participants) than for brief interventions (RR 1.30; 95% CI 1.16 to 1.46, 7 trials, 1141 participants). A single trial did not show evidence of benefit of a scheduled reduced smoking intervention. Neither nicotine lozenges nor varenicline were shown to increase cessation at the time of surgery but both had wide confidence intervals (RR 1.34; 95% CI 0.86 to 2.10 (1 trial, 46 participants) and RR 1.49; 95% CI 0.98 to 2.26 (1 trial, 286 participants) respectively). Four of these trials evaluated long-term smoking cessation and only the intensive intervention retained a significant effect (RR 2.96; 95% CI 1.57 to 5.55, 2 trials, 209 participants), whilst there was no evidence of a long-term effect following a brief intervention (RR 1.09; 95% CI 0.68 to 1.75, 2 trials, 341 participants). The trial of varenicline did show a significant effect on long-term smoking cessation (RR 1.45; 95% CI 1.01 to 2.07, 1 trial, 286 participants).Seven trials examined the effect of smoking intervention on postoperative complications. As with smoking outcomes, there was evidence of heterogeneity between intensive and brief behavioural interventions. In subgroup analyses there was a significant effect of intensive intervention on any complications (RR 0.42; 95% CI 0.27 to 0.65, 2 trials, 210 participants) and on wound complications (RR 0.31; 95% CI 0.16 to 0.62, 2 trials, 210 participants). For brief interventions, where the impact on smoking had been smaller, there was no evidence of a reduction in complications (RR 0.92; 95% CI 0.72 to 1.19, 4 trials, 493 participants) for any complication (RR 0.99; 95% CI 0.70 to 1.40, 3 trials, 325 participants) for wound complications. The trial of varenicline did not detect an effect on postoperative complications (RR 0.94; 95% CI 0.52 to 1.72, 1 trial, 286 participants).

Authors' conclusions: There is evidence that preoperative smoking interventions providing behavioural support and offering NRT increase short-term smoking cessation and may reduce postoperative morbidity. One trial of varenicline begun shortly before surgery has shown a benefit on long-term cessation but did not detect an effect on early abstinence or on postoperative complications. The optimal preoperative intervention intensity remains unknown. Based on indirect comparisons and evidence from two small trials, interventions that begin four to eight weeks before surgery, include weekly counselling and use NRT are more likely to have an impact on complications and on long-term smoking cessation.

Abstract
Patients who drink too much have more complications after surgery. The aim of this thesis was to evaluate the evidence, possible mechanisms, and prevention of the increased postoperative morbidity in alcohol abusers, defined by a consumption of at least five drinks per day. The literature could be criticised for several methodological flaws. Nevertheless, the results are in agreement showing moderate to strong evidence of increased postoperative morbidity after surgical procedures on alcohol abusers. There is weak to moderate evidence of increased postoperative mortality, hospital stay, and re-operation. The personal and economic consequences are tremendous. The incidence of alcohol abusers undergoing surgery was 7% to 49%, according to gender and diagnosis. They have been identified by a self-reported alcohol intake, which implies the possibility of underestimation. Alcohol markers could be used for a more precise identification of alcohol abuse. However, the inability of the questionnaires to detect short-term changes in intake and abuse without dependence, the inconsistent predictive values of the biological markers, and the lack of evidence of an association to postoperative morbidity reduces their usefulness. A detailed alcohol history is therefore recommended. The pathophysiology may include alcohol-induced organ dysfunctions. We demonstrated that subclinical cardiac insufficiency, immune incompetence, and haemostatic imbalance were already present preoperatively. A relation between the various lesions remains to be investigated. The surgical stress response was greater in alcohol abusers, which may further compromise the already dysfunctioning organs, thus leading to the documented increase in postoperative morbidity. Withdrawal from alcohol reverses organic dysfunction in non-surgical patients. Haemostasis normalises after one to four weeks, cardiac function after one month, immune function after two months, and response to external stress after three months. Accordingly, our small randomised investigation has shown that one month of abstinence before surgery improves several organic dysfunctions and reduces postoperative morbidity. We have demonstrated that prevention before surgery is possible. The study has methodological flaws, so further studies are required before final recommendations can be given. However, in the meantime clinical guidelines for alcohol abusers undergoing surgery should include up-to-date patient information and four weeks of abstinence before surgery, in accordance with the evidence-based association, the potential prevention attained by preoperative abstinence, and the best clinical practice. Implementation should be monitored in the clinical databases. In future, all patients admitted to surgery should be offered a health promoting dialogue with the surgeon, anaesthesiologist, general practitioner, or other health professionals, which focuses on alcohol among other risk factors in relation to the operative treatment, diagnosis and prognosis. A beneficial effect attainable from this multi-modal prevention and fast track surgery should be investigated among the alcohol abusers.

Abstract
Background: Preoperative risk assessment has become part of daily clinical practice, but preoperative alcohol abuse has not received much attention.

Methods: A Medline search was carried out to identify original papers published from 1967 to 1998. Relevant articles on postoperative morbidity in alcohol abusers were used to evaluate the evidence.

Results: Prospective and retrospective studies demonstrate a twofold to threefold increase in postoperative morbidity in alcohol abusers, the most frequent complications being infections, bleeding and cardiopulmonary insufficiency. Wound complications account for about half of the morbidity. The pathogenic mechanisms include preoperative immune incompetence, subclinical cardiac insufficiency and haemostatic imbalance. In addition, surgical trauma and/or postoperative abstinence result in an exaggerated stress response, which may further contribute to postoperative morbidity.

Conclusion: Alcohol consumption should be included in the preoperative assessment of likely postoperative outcome. Reduction of postoperative morbidity in alcohol abusers may include preoperative alcohol abstinence to improve organ function, or perioperative alcohol administration to avoid the abstinence response.

Abstract
Perioperative malnutrition has proven to be challenging to define, diagnose, and treat. Despite these challenges, it is well known that suboptimal nutritional status is a strong independent predictor of poor postoperative outcomes. Although perioperative caregivers consistently express recognition of the importance of nutrition screening and optimization in the perioperative period, implementation of evidence-based perioperative nutrition guidelines and pathways in the United States has been quite limited and needs to be addressed in surgery-focused recommendations. The second Perioperative Quality Initiative brought together a group of international experts with the objective of providing consensus recommendations on this important topic with the goal of (1) developing guidelines for screening of nutritional status to identify patients at risk for adverse outcomes due to malnutrition; (2) address optimal methods of providing nutritional support and optimizing nutrition status preoperatively; and (3) identifying when and how to optimize nutrition delivery in the postoperative period. Discussion led to strong recommendations for implementation of routine preoperative nutrition screening to identify patients in need of preoperative nutrition optimization. Postoperatively, nutrition delivery should be restarted immediately after surgery. The key role of oral nutrition supplements, enteral nutrition, and parenteral nutrition (implemented in that order) in most perioperative patients was advocated for with protein delivery being more important than total calorie delivery. Finally, the role of often-inadequate nutrition intake in the posthospital setting was discussed, and the role of postdischarge oral nutrition supplements was emphasized.

Abstract
Background: Functional capacity is an important component of risk assessment for major surgery. Doctors' clinical subjective assessment of patients' functional capacity has uncertain accuracy. We did a study to compare preoperative subjective assessment with alternative markers of fitness (cardiopulmonary exercise testing [CPET], scores on the Duke Activity Status Index [DASI] questionnaire, and serum N-terminal pro-B-type natriuretic peptide [NT pro-BNP] concentrations) for predicting death or complications after major elective non-cardiac surgery.

Methods: We did a multicentre, international, prospective cohort study at 25 hospitals: five in Canada, seven in the UK, ten in Australia, and three in New Zealand. We recruited adults aged at least 40 years who were scheduled for major non-cardiac surgery and deemed to have one or more risk factors for cardiac complications (eg, a history of heart failure, stroke, or diabetes) or coronary artery disease. Functional capacity was subjectively assessed in units of metabolic equivalents of tasks by the responsible anaesthesiologists in the preoperative assessment clinic, graded as poor (<4), moderate (4-10), or good (>10). All participants also completed the DASI questionnaire, underwent CPET to measure peak oxygen consumption, and had blood tests for measurement of NT pro-BNP concentrations. After surgery, patients had daily electrocardiograms and blood tests to measure troponin and creatinine concentrations until the third postoperative day or hospital discharge. The primary outcome was death or myocardial infarction within 30 days after surgery, assessed in all participants who underwent both CPET and surgery. Prognostic accuracy was assessed using logistic regression, receiver-operating-characteristic curves, and net risk reclassification.

Abstract
Background: Preoperative risk prediction is important for guiding clinical decision-making and resource allocation. Clinicians frequently rely solely on their own clinical judgement for risk prediction rather than objective measures. We aimed to compare the accuracy of freely available objective surgical risk tools with subjective clinical assessment in predicting 30-day mortality.

Methods and findings: We conducted a prospective observational study in 274 hospitals in the United Kingdom (UK), Australia, and New Zealand. For 1 week in 2017, prospective risk, surgical, and outcome data were collected on all adults aged 18 years and over undergoing surgery requiring at least a 1-night stay in hospital. Recruitment bias was avoided through an ethical waiver to patient consent; a mixture of rural, urban, district, and university hospitals participated. We compared subjective assessment with 3 previously published, open-access objective risk tools for predicting 30-day mortality: the Portsmouth-Physiology and Operative Severity Score for the enUmeration of Mortality (P-POSSUM), Surgical Risk Scale (SRS), and Surgical Outcome Risk Tool (SORT). We then developed a logistic regression model combining subjective assessment and the best objective tool and compared its performance to each constituent method alone. We included 22,631 patients in the study: 52.8% were female, median age was 62 years (interquartile range [IQR] 46 to 73 years), median postoperative length of stay was 3 days (IQR 1 to 6), and inpatient 30-day mortality was 1.4%. Clinicians used subjective assessment alone in 88.7% of cases. All methods overpredicted risk, but visual inspection of plots showed the SORT to have the best calibration. The SORT demonstrated the best discrimination of the objective tools (SORT Area Under Receiver Operating Characteristic curve [AUROC] = 0.90, 95% confidence interval [CI]: 0.88-0.92; P-POSSUM = 0.89, 95% CI 0.88-0.91; SRS = 0.85, 95% CI 0.82-0.87). Subjective assessment demonstrated good discrimination (AUROC = 0.89, 95% CI: 0.86-0.91) that was not different from the SORT (p = 0.309). Combining subjective assessment and the SORT improved discrimination (bootstrap optimism-corrected AUROC = 0.92, 95% CI: 0.90-0.94) and demonstrated continuous Net Reclassification Improvement (NRI = 0.13, 95% CI: 0.06-0.20, p < 0.001) compared with subjective assessment alone. Decision-curve analysis (DCA) confirmed the superiority of the SORT over other previously published models, and the SORT-clinical judgement model again performed best overall. Our study is limited by the low mortality rate, by the lack of blinding in the 'subjective' risk assessments, and because we only compared the performance of clinical risk scores as opposed to other prediction tools such as exercise testing or frailty assessment.

Conclusions: In this study, we observed that the combination of subjective assessment with a parsimonious risk model improved perioperative risk estimation. This may be of value in helping clinicians allocate finite resources such as critical care and to support patient involvement in clinical decision-making.