Restrictive versus conventional ward fluid therapy in non-cardiac surgery patients and the effect on postoperative complications: a meta-analysis.

BACKGROUND: Diligent fluid management is an instrumental part of Enhanced Recovery After Surgery. However, the effect of a ward regimen to limit intravenous fluid administration on outcome remains unclear. We performed a meta-analysis investigating the effect of a restrictive versus a conventional fluid regimen on complications in patients after non-cardiac surgery in the postoperative period on the clinical ward. STUDY DESIGN: We performed a systematic search in MEDLINE, Embase, Cochrane Library, and CINAHL databases, from the start of indexing until June 2022, with constraints for English language and adult human study participants. Data were combined using classic methods of meta-analyses and were expressed as weighted pooled risk ratio (RR) or odds ratio (OR) with 95% confidence interval (CI). Quality assessment and risk of bias analyses was performed according to PRISMA guidelines. RESULTS: Seven records, three randomized controlled trials, and four non-randomized studies were included with a total of 883 patients. A restrictive fluid regimen was associated with a reduction in overall complication rate in the RCTs (RR 0.46, 95% CI 0.23 to 0.95; P < .03; I2 = 35%). This reduction in overall complication rate was not consistent in the non-randomized studies (RR 0.74, 95% CI 0.53 to 1.03; P 0.07; I2 = 45%). No significant association was found for mortality using a restrictive fluid regimen (RCTs OR 0.51, 95% CI 0.05 to 4.90; P = 0.56; I2 = 0%, non-randomized studies OR 0.30, 95% CI 0.06 to 1.46; P = 0.14; I2 = 0%). A restrictive fluid regimen is significantly associated with a reduction in postoperative length of stay in the non-randomized studies (MD - 1.81 days, 95% CI - 3.27 to - 0.35; P = 0.01; I2 = 0%) but not in the RCTs (MD 0.60 days, 95% CI - 0.75 to 1.95; P = 0.38). Risk of bias was moderate to high. Methodological quality was very low to moderate. CONCLUSION: This meta-analysis suggests restrictive fluid therapy on the ward may be associated with an effect on postoperative complication rate. However, the quality of evidence was moderate to low, the sample size was small, and the data came from both RCTs and non-randomized studies.

The effects of neoadjuvant chemoradiotherapy and an in-hospital exercise training programme on physical fitness and quality of life in locally advanced rectal cancer patients: a randomised controlled trial (The EMPOWER Trial).

BACKGROUND: The EMPOWER trial aimed to assess the effects of a 9-week exercise prehabilitation programme on physical fitness compared with a usual care control group. Secondary aims were to investigate the effect of (1) the exercise prehabilitation programme on psychological health; and (2) neoadjuvant chemoradiotherapy (NCRT) on physical fitness and psychological health. METHODS: Between October 2013 and December 2016, adults with locally advanced rectal cancer undergoing standardised NCRT and surgery were recruited to a multi-centre trial. Patients underwent cardiopulmonary exercise testing (CPET) and completed HRQoL questionnaires (EORTC-QLQ-C30 and EQ-5D-5L) pre-NCRT and post-NCRT (week 0/baseline). At week 0, patients were randomised to exercise prehabilitation or usual care (no intervention). CPET and HRQoL questionnaires were assessed at week 0, 3, 6 and 9, whilst semi-structured interviews were assessed at week 0 and week 9. Changes in oxygen uptake at anaerobic threshold (VO2 at AT (ml kg-1 min-1)) between groups were compared using linear mixed modelling. RESULTS: Thirty-eight patients were recruited, mean age 64 (10.4) years. Of the 38 patients, 33 were randomised: 16 to usual care and 17 to exercise prehabilitation (26 males and 7 females). Exercise prehabilitation significantly improved VO2 at AT at week 9 compared to the usual care. The change from baseline to week 9, when adjusted for baseline, between the randomised groups was + 2.9 ml kg -1 min -1; (95% CI 0.8 to 5.1), p = 0.011. CONCLUSION: A 9-week exercise prehabilitation programme significantly improved fitness following NCRT. These findings have informed the WesFit trial (NCT03509428) which is investigating the effects of community-based multimodal prehabilitation before cancer surgery. TRIAL REGISTRATION: ClinicalTrials.gov NCT01914068 . Registered 1 August 2013.

Postoperative acute kidney injury in adult non-cardiac surgery: joint consensus report of the Acute Disease Quality Initiative and PeriOperative Quality Initiative.

Postoperative acute kidney injury (PO-AKI) is a common complication of major surgery that is strongly associated with short-term surgical complications and long-term adverse outcomes, including increased risk of chronic kidney disease, cardiovascular events and death. Risk factors for PO-AKI include older age and comorbid diseases such as chronic kidney disease and diabetes mellitus. PO-AKI is best defined as AKI occurring within 7 days of an operative intervention using the Kidney Disease Improving Global Outcomes (KDIGO) definition of AKI; however, additional prognostic information may be gained from detailed clinical assessment and other diagnostic investigations in the form of a focused kidney health assessment (KHA). Prevention of PO-AKI is largely based on identification of high baseline risk, monitoring and reduction of nephrotoxic insults, whereas treatment involves the application of a bundle of interventions to avoid secondary kidney injury and mitigate the severity of AKI. As PO-AKI is strongly associated with long-term adverse outcomes, some form of follow-up KHA is essential; however, the form and location of this will be dictated by the nature and severity of the AKI. In this Consensus Statement, we provide graded recommendations for AKI after non-cardiac surgery and highlight priorities for future research.

Divergent trajectories of cellular bioenergetics, intermediary metabolism and systemic redox status in survivors and non-survivors of critical illness.

BACKGROUND: Numerous pathologies result in multiple-organ failure, which is thought to be a direct consequence of compromised cellular bioenergetic status. Neither the nature of this phenotype nor its relevance to survival are well understood, limiting the efficacy of modern life-support. METHODS: To explore the hypothesis that survival from critical illness relates to changes in cellular bioenergetics, we combined assessment of mitochondrial respiration with metabolomic, lipidomic and redox profiling in skeletal muscle and blood, at multiple timepoints, in 21 critically ill patients and 12 reference patients. RESULTS: We demonstrate an end-organ cellular phenotype in critical illness, characterized by preserved total energetic capacity, greater coupling efficiency and selectively lower capacity for complex I and fatty acid oxidation (FAO)-supported respiration in skeletal muscle, compared to health. In survivors, complex I capacity at 48 h was 27% lower than in non-survivors (p = 0.01), but tended to increase by day 7, with no such recovery observed in non-survivors. By day 7, survivors' FAO enzyme activity was double that of non-survivors (p = 0.048), in whom plasma triacylglycerol accumulated. Increases in both cellular oxidative stress and reductive drive were evident in early critical illness compared to health. Initially, non-survivors demonstrated greater plasma total antioxidant capacity but ultimately higher lipid peroxidation compared to survivors. These alterations were mirrored by greater levels of circulating total free thiol and nitrosated species, consistent with greater reductive stress and vascular inflammation, in non-survivors compared to survivors. In contrast, no clear differences in systemic inflammatory markers were observed between the two groups. CONCLUSION: Critical illness is associated with rapid, specific and coordinated alterations in the cellular respiratory machinery, intermediary metabolism and redox response, with different trajectories in survivors and non-survivors. Unravelling the cellular and molecular foundation of human resilience may enable the development of more effective life-support strategies.

A feasibility randomised controlled trial of targeted oxygen therapy in mechanically ventilated critically ill patients.

BACKGROUND: Despite oxygen being the commonest drug administered to critically ill patients we do not know which oxygen saturation (SpO2) target results in optimal survival outcomes in those receiving mechanical ventilation. We therefore conducted a feasibility randomised controlled trial in the United Kingdom (UK) to assess whether it would be possible to host a larger national multi-centre trial to evaluate oxygenation targets in mechanically ventilated patients. METHODS: We set out to recruit 60 participants across two sites into a trial in which they were randomised to receive conservative oxygenation (SpO2 88-92%) or usual care (control - SpO2 ≥96%). The primary outcome was feasibility; factors related to safety and clinical outcomes were also assessed. RESULTS: A total of 34 patients were recruited into the study until it was stopped due to time constraints. A number of key barriers to success were identified during the course of the study. The conservative oxygenation intervention was feasible and appeared to be safe in this small patient cohort and it achieved wide separation of the median time-weighted average (IQR) SpO2 at 91% (90-92%) in conservative oxygenation group versus 97% (96-97%) in control group. CONCLUSION: Whilst conservative oxygenation was a feasible and safe intervention which achieved clear group separation in oxygenation levels, the model used in this trial will require alterations to improve future participant recruitment rates in the UK.

The effects of cancer therapies on physical fitness before oesophagogastric cancer surgery: a prospective, blinded, multi-centre, observational, cohort study.

Background: Neoadjuvant cancer treatment is associated with improved survival following major oesophagogastric cancer surgery. The impact of neoadjuvant chemo/chemoradiotherapy on physical fitness and operative outcomes is however unclear. This study aims to investigate the impact of neoadjuvant chemo/chemoradiotherapy on fitness and post-operative mortality. Methods: Patients with oesophagogastric cancer scheduled for chemo/chemoradiotherapy and surgery were recruited to a prospective, blinded, multi-centre, observational cohort study. Primary outcomes were changes in fitness with chemo/chemoradiotherapy, measured using cardiopulmonary exercise testing and its association with mortality one-year after surgery. Patients were followed up for re-admission at 30-days, in-hospital morbidity and quality of life (exploratory outcomes). Results: In total, 384 patients were screened, 217 met the inclusion criteria, 160 consented and 159 were included (72% male, mean age 65 years). A total of 132 patients (83%) underwent chemo/chemoradiotherapy, 109 (71%) underwent chemo/chemoradiotherapy and two exercise tests, 100 (63%) completed surgery and follow-up. A significant decline in oxygen uptake at anaerobic threshold and oxygen uptake peak was observed following chemo/chemoradiotherapy: -1.25ml.kg -1.min -1 (-1.80 to -0.69) and -3.02ml.kg -1.min -1 (-3.85 to -2.20); p<0.0001). Baseline chemo/chemoradiotherapy anaerobic threshold and peak were associated with one-year mortality (HR=0.72, 95%CI 0.59 to 0.88; p=0.001 and HR=0.85, 0.76 to 0.95; p=0.005). The change in physical fitness was not associated with one-year mortality. Conclusions: Chemo/chemoradiotherapy prior to oesophagogastric cancer surgery reduced physical fitness. Lower baseline fitness was associated with reduced overall survival at one-year. Careful consideration of fitness prior to chemo/chemoradiotherapy and surgery is urgently needed.

BACKGROUND: Cancer treatments such as chemotherapy and radiotherapy given to people with oesophageal and gastric cancer (also known as cancer of the food pipe/stomach) before surgery can improve survival. However, the impact such treatments have on fitness and recovery after surgery is unclear. The aim of this research was to understand the impact cancer treatments has on fitness and any complications after surgery. METHODS: Patients with oesophageal and gastric cancer (also known as cancer of the food pipe/stomach) who were being treated by cancer treatment and surgery were recruited from different hospitals in the UK. All participants were asked to undertake an exercise test to measure fitness and fill out questionnaires to measure quality of life before and after cancer treatment. Complications patients experienced after surgery, the number of patients who had to be readmitted to hospital 30 days after surgery and one-year survival was recorded. RESULTS: A total of 160 consented to participate in this study and 159 were included in the study (72% male, average age 65 years). In total, 132 patients (83%) had cancer treatment, 109 (71%) had cancer treatment and the two exercise tests and 100 (63%) had surgery and were followed-up after surgery. Study findings show that fitness reduced after cancer treatment. Patient's fitness levels at the start of the study (or before cancer treatment) were linked to one-year survival. The fall in fitness after cancer treatment was not linked to death at the one-year follow-up. CONCLUSION: Cancer treatments before oesophageal and gastric cancer reduce fitness. Patients with a lower fitness level before cancer treatment had a reduced overall survival at one-year. Careful consideration of fitness prior to such cancer treatments and surgery is urgently needed.

The effect of adding goal-directed hemodynamic management for elective patients in an established enhanced recovery program for colorectal surgery: results of quasi-experimental pragmatic trial.

BACKGROUND: Recent literature has demonstrated that hemodynamic instability in the intraoperative period places patients at risk of poor outcomes. Furthermore, recent studies have reported that stroke volume optimization and protocolized hemodynamic management may improve perioperative outcomes, especially surgical site infection (SSI), in certain high-risk populations. However, the optimal strategy for intraoperative management of all elective patients within an enhanced recovery program remains to be elucidated. METHODS: We performed a pre-post quasi-experimental study to assess the effect of adding goal-directed hemodynamic therapy to an enhanced recovery program (ERP) for colorectal surgery on SSI and other outcomes. Three groups were compared: "Pre-ERP," defined as historical control (before enhanced recovery program); "ERP," defined as enhanced recovery program using zero fluid balance; and "ERP+GDHT," defined as enhanced recovery program plus goal-directed hemodynamic therapy. Outcomes were obtained through our National Surgical Quality Improvement Program participation. RESULTS: A total of 623 patients were included in the final analysis (Pre-ERP = 246, ERP = 140, and ERP + GDHT = 237). Demographics and baseline clinical characteristics were balanced between groups. We did not observe statistically significant differences in SSI or composite complication rates in unadjusted or adjusted analysis. There was no evidence of association between study group and 30-day readmission. American Society of Anesthesiologists status ≥ 3 and open surgical approach were significantly associated with increased risk of SSI, composite complication, and 30-day readmission (p < 0.05 for all) in all groups. CONCLUSIONS: There was no evidence that addition of goal-directed hemodynamic therapy for all patients in an enhanced recovery program for colorectal surgery affects the risk of SSI, composite complications, or 30-day readmission. Further research is needed to investigate whether there is benefit of goal-directed hemodynamic therapy for select high-risk populations. TRIAL REGISTRATION: NCT03189550. Registered 16 June 2017-Retrospectively registered, https://www.clinicaltrials.gov/ct2/results?cond=&term=NCT03189550&cntry=&state=&city=&dist=.

Evaluating enhanced recovery after surgery: time to cover new ground and discover the missing patient voice.

Multicomponent peri-operative interventions offer to accelerate patient recovery and improve cost-effectiveness. The recent National Institute of Health Research-commissioned evidence synthesis review by Nunns et al. considers the effectiveness and cost-effectiveness of all types of multicomponent interventions for older adults undergoing elective inpatient surgery. Enhanced recovery programmes (ERPs) were the most commonly evaluated intervention. An association between ERPs and decreased length of stay was observed, whilst complication rates and time to recovery were static or sometimes reduced. Important areas which lack research in the context of ERPs are patient-reported outcome measures, patients with complex needs and assessment of factors pertaining to successful ERP implementation. The next generation of ERP studies should seek to develop our understanding in these key areas.

Enhanced flow-motion complexity of skin microvascular perfusion in Sherpas and lowlanders during ascent to high altitude.

An increased and more effective microvascular perfusion is postulated to play a key role in the physiological adaptation of Sherpa highlanders to the hypobaric hypoxia encountered at high altitude. To investigate this, we used Lempel-Ziv complexity (LZC) analysis to explore the spatiotemporal dynamics of the variability of the skin microvascular blood flux (BF) signals measured at the forearm and finger, in 32 lowlanders (LL) and 46 Sherpa highlanders (SH) during the Xtreme Everest 2 expedition. Measurements were made at baseline (BL) (LL: London 35 m; SH: Kathmandu 1300 m) and at Everest base camp (LL and SH: EBC 5,300 m). We found that BF signal content increased with ascent to EBC in both SH and LL. At both altitudes, LZC of the BF signals was significantly higher in SH, and was related to local slow-wave flow-motion activity over multiple spatial and temporal scales. In SH, BF LZC was also positively associated with LZC of the simultaneously measured tissue oxygenation signals. These data provide robust mechanistic information of microvascular network functionality and flexibility during hypoxic exposure on ascent to high altitude. They demonstrate the importance of a sustained heterogeneity of network perfusion, associated with local vaso-control mechanisms, to effective tissue oxygenation during hypobaric hypoxia.

American Society for Enhanced Recovery and Perioperative Quality Initiative Joint Consensus Statement on Perioperative Opioid Minimization in Opioid-Naïve Patients.

Surgical care episodes place opioid-naïve patients at risk for transitioning to new persistent postoperative opioid use. With one of the central principles being the application of multimodal pain interventions to reduce the reliance on opioid-based medications, enhanced recovery pathways provide a framework that decreases perioperative opioid use. The fourth Perioperative Quality Initiative brought together a group of international experts representing anesthesiology, surgery, and nursing with the objective of providing consensus recommendations on this important topic. Fourth Perioperative Quality Initiative was a consensus-building conference designed around a modified Delphi process in which the group alternately convened for plenary discussion sessions in between small group discussions. The process included several iterative steps including a literature review of the topics, building consensus around the important questions related to the topic, and sequential steps of content building and refinement until agreement was achieved and a consensus document was produced. During the fourth Perioperative Quality Initiative conference and thereafter as a writing group, reference applicability to the topic was discussed in any area where there was disagreement. For this manuscript, the questions answered included (1) What are the potential strategies for preventing persistent postoperative opioid use? (2) Is opioid-free anesthesia and analgesia feasible and appropriate for routine operations? and (3) Is opioid-free (intraoperative) anesthesia associated with equivalent or superior outcomes compared to an opioid minimization in the perioperative period? We will discuss the relevant literature for each questions, emphasize what we do not know, and prioritize the areas for future research.

Systematic review and consensus definitions for the Standardised Endpoints in Perioperative Medicine (StEP) initiative: infection and sepsis.

BACKGROUND: Perioperative infection and sepsis are of fundamental concern to perioperative clinicians. However, standardised endpoints are either poorly defined or not routinely implemented. The Standardised Endpoints in Perioperative Medicine (StEP) initiative was established to derive a set of standardised endpoints for use in perioperative clinical trials. METHODS: We undertook a systematic review to identify measures of infection and sepsis used in the perioperative literature. A multi-round Delphi consensus process that included more than 60 clinician researchers was then used to refine a recommended list of outcome measures. RESULTS: A literature search yielded 1857 titles of which 255 met inclusion criteria for endpoint extraction. A long list of endpoints, with definitions and timescales, was generated and those potentially relevant to infection and sepsis circulated to the theme subgroup and then the wider StEP-COMPAC working group, undergoing a three-stage Delphi process. The response rates for Delphi rounds 1, 3, and 3 were 89% (n=8), 67% (n=62), and 80% (n=8), respectively. A set of 13 endpoints including fever, surgical site, and organ-specific infections as defined by the US Centres for Disease Control and Sepsis-3 are proposed for future use. CONCLUSIONS: We defined a consensus list of standardised endpoints related to infection and sepsis for perioperative trials using an established and rigorous approach. Each endpoint was evaluated with respect to validity, reliability, feasibility, and patient centredness. One or more of these should be considered for inclusion in future perioperative clinical trials assessing infection, sepsis, or both, thereby permitting synthesis and comparison of future results.

American Society for Enhanced Recovery and Perioperative Quality Initiative Joint Consensus Statement on Perioperative Management of Patients on Preoperative Opioid Therapy.

Enhanced recovery pathways have quickly become part of the standard of care for patients undergoing elective surgery, especially in North America and Europe. One of the central tenets of this multidisciplinary approach is the use of multimodal analgesia with opioid-sparing and even opioid-free anesthesia and analgesia. However, the current state is a historically high use of opioids for both appropriate and inappropriate reasons, and patients with chronic opioid use before their surgery represent a common, often difficult-to-manage population for the enhanced recovery providers and health care team at large. Furthermore, limited evidence and few proven successful protocols exist to guide providers caring for these at-risk patients throughout their elective surgical experience. Therefore, the fourth Perioperative Quality Initiative brought together an international team of multidisciplinary experts, including anesthesiologists, nurse anesthetists, surgeons, pain specialists, neurologists, nurses, and other experts with the objective of providing consensus recommendations. Specifically, the goal of this consensus document is to minimize opioid-related complications by providing expert-based consensus recommendations that reflect the strength of the medical evidence regarding: (1) the definition, categorization, and risk stratification of patients receiving opioids before surgery; (2) optimal perioperative treatment strategies for patients receiving preoperative opioids; and (3) optimal discharge and continuity of care management practices for patients receiving opioids preoperatively. The overarching theme of this document is to provide health care providers with guidance to reduce potentially avoidable opioid-related complications including opioid dependence (both physical and behavioral), disability, and death. Enhanced recovery programs attempt to incorporate best practices into pathways of care. By presenting the available evidence for perioperative management of patients on opioids, this consensus panel hopes to encourage further development of pathways specific to this high-risk group to mitigate the often unintentional iatrogenic and untoward effects of opioids and to improve perioperative outcomes.

Perioperative administration of buffered versus non-buffered crystalloid intravenous fluid to improve outcomes following adult surgical procedures: a Cochrane systematic review.

BACKGROUND: Buffered intravenous fluid preparations contain substrates to maintain acid-base status. The objective of this systematic review was to compare the effects of buffered and non-buffered fluids administered during the perioperative period on clinical and biochemical outcomes. METHODS: We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library until May 2017 and included all randomised controlled trials that evaluated buffered versus non-buffered fluids, whether crystalloid or colloid, administered to surgical patients. We assessed the selected studies for risk of bias and graded the level of evidence in accordance with Cochrane recommendations. RESULTS: We identified 19 publications of 18 randomised controlled trials, totalling 1096 participants. Mean difference (MD) in postoperative pH was 0.05 units lower immediately following surgery in the non-buffered group (12 studies of 720 participants; 95% confidence interval (CI) 0.04 to 0.07; I 2 = 61%). This difference did not persist on postoperative day 1. Serum chloride concentration was higher in the non-buffered group at the end of surgery (10 trials of 530 participants; MD 6.77 mmol/L, 95% CI 3.38 to 10.17). This effect persisted until postoperative day 1 (5 trials of 258 participants; MD 8.48 mmol/L, 95% CI 1.08 to 15.88). Quality of this evidence was moderate. We identified variable protocols for fluid administration and total volumes of fluid administered to patients intraoperatively. Outcome data was variably reported at disparate time points and with heterogeneous patient groups. Consequently, the effect size and overall confidence interval was reduced, despite the relatively low inherent risk of bias. There was insufficient evidence on the effect of fluid composition on mortality and organ dysfunction. Confidence intervals of this outcome were wide and the quality of evidence was low (3 trials of 276 participants for mortality; odds ratio (OR) 1.85, 95% CI 0.37 to 9.33; I 2 = 0%). CONCLUSIONS: Small effect sizes for biochemical outcomes and lack of correlated clinical follow-up data mean that robust conclusions on major morbidity and mortality associated with buffered versus non-buffered perioperative fluid choices are still lacking. Buffered fluid may have biochemical benefits, including a significant reduction in postoperative hyperchloraemia and metabolic acidosis.

Pulmonary artery catheter use in adult patients undergoing cardiac surgery: a retrospective, cohort study.

BACKGROUND: The utility of pulmonary artery catheters (PACs) and their measurements depend on a variety of factors including data interpretation and personnel training. This US multi-center, retrospective electronic health record (EHR) database analysis was performed to identify associations between PAC use in adult cardiac surgeries and effects on subsequent clinical outcomes. METHODS: This cohort analysis utilized the Cerner Health Facts database to examine patients undergoing isolated coronary artery bypass graft (CABG), isolated valve surgery, aortic surgery, other complex non-valvular and multi-cardiac procedures, and/or heart transplant from January 1, 2011, to June 30, 2015. A total of 6844 adults in two cohorts, each with 3422 patients who underwent a qualifying cardiac procedure with or without the use of a PAC for monitoring purposes, were included. Patients were matched 1:1 using a propensity score based upon the date and type of surgery, hospital demographics, modified European System for Cardiac Operative Risk Evaluation (EuroSCORE II), and patient characteristics. Primary outcomes of 30-day in-hospital mortality, length of stay, cardiopulmonary morbidity, and infectious morbidity were analyzed after risk adjustment for acute physiology score. RESULTS: There was no difference in the 30-day in-hospital mortality rate between treatment groups (OR, 1.17; 95% CI, 0.65-2.10; p = 0.516). PAC use was associated with a decreased length of stay (9.39 days without a PAC vs. 8.56 days with PAC; p < 0.001), a decreased cardiopulmonary morbidity (OR, 0.87; 95% CI, 0.79-0.96; p < 0.001), and an increased infectious morbidity (OR, 1.28; 95% CI, 1.10-1.49; p < 0.001). CONCLUSIONS: Use of a PAC during adult cardiac surgery is associated with decreased length of stay, reduced cardiopulmonary morbidity, and increased infectious morbidity but no increase in the 30-day in-hospital mortality. This suggests an overall potential benefit associated with PAC-based monitoring in this population. TRIAL REGISTRATION: The study was registered at clinicaltrials.gov (NCT02964026) on November 15, 2016.

The Smell of Hypoxia: using an electronic nose at altitude and proof of concept of its role in the prediction and diagnosis of acute mountain sickness.

Electronic nose (e-nose) devices may be used to identify volatile organic compounds (VOCs) in exhaled breath. VOCs generated via metabolic processes are candidate biomarkers of (patho)physiological pathways. We explored the feasibility of using an e-nose to generate human "breathprints" at high altitude. Furthermore, we explored the hypothesis that pathophysiological processes involved in the development of acute mountain sickness (AMS) would manifest as altered VOC profiles. Breath analysis was performed on Sherpa and lowlander trekkers at high altitude (3500 m). The Lake Louise Scoring (LLS) system was used to diagnose AMS. Raw data were reduced by principal component (PC) analysis (PCA). Cross validated linear discriminant analysis (CV-LDA) and receiver-operating characteristic area under curve (ROC-AUC) assessed discriminative function. Breathprints suitable for analysis were obtained from 58% (37/64) of samples. PCA showed significant differences between breathprints from participants with, and without, AMS; CV-LDA showed correct classification of 83.8%, ROC-AUC 0.86; PC 1 correlated with AMS severity. There were significant differences between breathprints of participants who remained AMS negative and those whom later developed AMS (CV-LDA 68.8%, ROC-AUC 0.76). PCA demonstrated discrimination between Sherpas and lowlanders (CV-LDA 89.2%, ROC-AUC 0.936). This study demonstrated the feasibility of breath analysis for VOCs using an e-nose at high altitude. Furthermore, it provided proof-of-concept data supporting e-nose utility as an objective tool in the prediction and diagnosis of AMS. E-nose technology may have substantial utility both in altitude medicine and under other circumstances where (mal)adaptation to hypoxia may be important (e.g., critically ill patients).

American Society for Enhanced Recovery and Perioperative Quality Initiative Joint Consensus Statement on Nutrition Screening and Therapy Within a Surgical Enhanced Recovery Pathway.

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.

American Society for Enhanced Recovery and Perioperative Quality Initiative Joint Consensus Statement on Patient-Reported Outcomes in an Enhanced Recovery Pathway.

Patient-reported outcomes (PROs) are measures of health status that come directly from the patient. PROs are an underutilized tool in the perioperative setting. Enhanced recovery pathways (ERPs) have primarily focused on traditional measures of health care quality such as complications and hospital length of stay. These measures do not capture postdischarge outcomes that are meaningful to patients such as function or freedom from disability. PROs can be used to facilitate shared decisions between patients and providers before surgery and establish benchmark recovery goals after surgery. PROs can also be utilized in quality improvement initiatives and clinical research studies. An expert panel, the Perioperative Quality Initiative (POQI) workgroup, conducted an extensive literature review to determine best practices for the incorporation of PROs in an ERP. This international group of experienced clinicians from North America and Europe met at Stony Brook, NY, on December 2-3, 2016, to review the evidence supporting the use of PROs in the context of surgical recovery. A modified Delphi method was used to capture the collective expertise of a diverse group to answer clinical questions. During 3 plenary sessions, the POQI PRO subgroup presented clinical questions based on a literature review, presented evidenced-based answers to those questions, and developed recommendations which represented a consensus opinion regarding the use of PROs in the context of an ERP. The POQI workgroup identified key criteria to evaluate patient-reported outcome measures (PROMs) for their incorporation in an ERP. The POQI workgroup agreed on the following recommendations: (1) PROMs in the perioperative setting should be collected in the framework of physical, mental, and social domains. (2) These data should be collected preoperatively at baseline, during the immediate postoperative time period, and after hospital discharge. (3) In the immediate postoperative setting, we recommend using the Quality of Recovery-15 score. After discharge at 30 and 90 days, we recommend the use of the World Health Organization Disability Assessment Scale 2.0, or a tailored use of the Patient-Reported Outcomes Measurement Information System. (4) Future study that consistently applies PROMs in an ERP will define the role these measures will have evaluating quality and guiding clinical care. Consensus guidelines regarding the incorporation of PRO measures in an ERP were created by the POQI workgroup. The inclusion of PROMs with traditional measures of health care quality after surgery provides an opportunity to improve clinical care.

Perioperative administration of buffered versus non-buffered crystalloid intravenous fluid to improve outcomes following adult surgical procedures.

BACKGROUND: Perioperative fluid strategies influence clinical outcomes following major surgery. Many intravenous fluid preparations are based on simple solutions, such as normal saline, that feature an electrolyte composition that differs from that of physiological plasma. Buffered fluids have a theoretical advantage of containing a substrate that acts to maintain the body's acid-base status - typically a bicarbonate or a bicarbonate precursor such as maleate, gluconate, lactate, or acetate. Buffered fluids also provide additional electrolytes, including potassium, magnesium, and calcium, more closely matching the electrolyte balance of plasma. The putative benefits of buffered fluids have been compared with those of non-buffered fluids in the context of clinical studies conducted during the perioperative period. This review was published in 2012, and was updated in 2017. OBJECTIVES: To review effects of perioperative intravenous administration of buffered versus non-buffered fluids for plasma volume expansion or maintenance, or both, on clinical outcomes in adults undergoing all types of surgery. SEARCH METHODS: We electronically searched the Clinicaltrials.gov major trials registry, the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 6) in the Cochrane Library, MEDLINE (1966 to June 2016), Embase (1980 to June 2016), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to June 2016). We handsearched conference abstracts and, when possible, contacted leaders in the field. We reran the search in May 2017. We added one potential new study of interest to the list of 'Studies awaiting classification' and will incorporate this trial into formal review findings when we prepare the review update. SELECTION CRITERIA: Only randomized controlled trials that compared buffered versus non-buffered intravenous fluids for surgical patients were eligible for inclusion. We excluded other forms of comparison such as crystalloids versus colloids and colloids versus different colloids. DATA COLLECTION AND ANALYSIS: Two review authors screened references for eligibility, extracted data, and assessed risks of bias. We resolved disagreements by discussion and consensus, in collaboration with a third review author. We contacted trial authors to request additional information when appropriate. We presented pooled estimates for dichotomous outcomes as odds ratios (ORs) and for continuous outcomes as mean differences (MDs), with 95% confidence intervals (CIs). We analysed data via Review Manager 5.3 using fixed-effect models, and when heterogeneity was high (I² > 40%), we used random-effects models. MAIN RESULTS: This review includes, in total, 19 publications of 18 randomized controlled trials with a total of 1096 participants. We incorporated five of those 19 studies (330 participants) after the June 2016 update. Outcome measures in the included studies were thematically similar, covering perioperative electrolyte status, renal function, and acid-base status; however, we found significant clinical and statistical heterogeneity among the included studies. We identified variable protocols for fluid administration and total volumes of fluid administered to patients intraoperatively. Trial authors variably reported outcome data at disparate time points and with heterogeneous patient groups. Consequently, many outcome measures are reported in small group sizes, reducing overall confidence in effect size, despite relatively low inherent bias in the included studies. Several studies reported orphan outcome measures. We did not include in the results of this review one large, ongoing study of saline versus Ringer's solution.We found insufficient evidence on effects of fluid therapies on mortality and postoperative organ dysfunction (defined as renal insufficiency leading to renal replacement therapy); confidence intervals were wide and included both clinically relevant benefit and harm: mortality (Peto OR 1.85, 95% CI 0.37 to 9.33; I² = 0%; 3 trials, 6 deaths, 276 participants; low-quality evidence); renal insufficiency (OR 0.82, 95% CI 0.34 to 1.98; I² = 0%; 4 trials, 22 events, 276 participants; low-quality evidence).We noted several metabolic differences, including a difference in postoperative pH measured at end of surgery of 0.05 units - lower in the non-buffered fluid group (12 studies with a total of 720 participants; 95% CI 0.04 to 0.07; I² = 61%). However, this difference was not maintained on postoperative day one. We rated the quality of evidence for this outcome as moderate. We observed a higher postoperative serum chloride level immediately after operation, with use of non-buffered fluids reported in 10 studies with a total of 530 participants (MD 6.77 mmol/L, 95% CI 3.38 to 10.17), and this difference persisted until day one postoperatively (five studies with a total of 258 participants; MD 8.48 mmol/L, 95% CI 1.08 to 15.88). We rated the quality of evidence for this outcome as moderate. AUTHORS' CONCLUSIONS: Current evidence is insufficient to show effects of perioperative administration of buffered versus non-buffered crystalloid fluids on mortality and organ system function in adult patients following surgery. Benefits of buffered fluid were measurable in biochemical terms, particularly a significant reduction in postoperative hyperchloraemia and metabolic acidosis. Small effect sizes for biochemical outcomes and lack of correlated clinical follow-up data mean that robust conclusions on major morbidity and mortality associated with buffered versus non-buffered perioperative fluid choices are still lacking. Larger studies are needed to assess these relevant clinical outcomes.