Association of the TyG index with prognosis in surgical intensive care patients: data from the MIMIC-IV.

BACKGROUND: The triglyceride-glucose (TyG) index, a tool for assessing insulin resistance, is increasingly recognized for its ability to predict cardiovascular and metabolic risks. However, its relationship with trauma and surgical patient prognosis is understudied. This study investigated the correlation between the TyG index and mortality risk in surgical/trauma ICU patients to identify high-risk individuals and improve prognostic strategies. METHODS: This study identified patients requiring trauma/surgical ICU admission from the Medical Information Mart for Intensive Care (MIMIC-IV) database, and divided them into tertiles based on the TyG index. The outcomes included 28-day mortality and 180-day mortality for short-term and long-term prognosis. The associations between the TyG index and clinical outcomes in patients were elucidated using Cox proportional hazards regression analysis and RCS models. RESULTS: A total of 2103 patients were enrolled. The 28-day mortality and 180-day mortality rates reached 18% and 24%, respectively. Multivariate Cox proportional hazards analysis revealed that an elevated TyG index was significantly related to 28-day and 180-day mortality after covariates adjusting. An elevated TyG index was significantly associated with 28-day mortality (adjusted hazard ratio, 1.19; 95% confidence interval 1.04-1.37) and 180-day mortality (adjusted hazard ratio, 1.24; 95% confidence interval 1.11-1.39). RCS models revealed that a progressively increasing risk of mortality was related to an elevated TyG index. According to our subgroup analysis, an elevated TyG index is associated with increased risk of 28-day and 180-day mortality in critically ill patients younger than 60 years old, as well as those with concomitant stroke or cardiovascular diseases. Additionally, in nondiabetic patients, an elevated TyG index is associated with 180-day mortality. CONCLUSION: An increasing risk of mortality was related to an elevated TyG index. In critically ill patients younger than 60 years old, as well as those with concomitant stroke or cardiovascular diseases, an elevated TyG index is associated with adverse short-term and long-term outcomes. Furthermore, in non-diabetic patients, an elevated TyG index is associated with adverse long-term prognosis.

The safety and efficacy of balanced crystalloid vs. normal saline in non-cardiac surgeries - A systematic review and meta-analysis.

OBJECTIVE: Balanced crystalloid and normal saline are routinely used in clinical anesthesia, but their safety and efficacy in non-cardiac surgeries are still unclear. MATERIALS AND METHODS: PubMed, Embase, Web of Science, Cochrane Library, Wanfang, and CNKI, from January 1980 to March 2023, were searched. Studies comparing balanced crystalloid (BC) with normal saline (NS) during non-cardiac surgeries were included. The primary outcomes were clinical outcomes (acidosis, renal insufficiency, and mortality), and the secondary outcomes were pH value, Na+, Cl- and creatinine levels, and vasopressor requirement. RESULTS: Forty-three RCTs were included in this meta-analysis. Low evidence revealed that the development of acidosis was lower in the BC group than in the NS group (OR: 0.05, 95% CI: 0.01-0.43, I2=80.8%, p=0.00), and no between-group difference exists in renal insufficiency and mortality. At the end of surgery and on postoperative day 1 (POD 1), the pH value was higher, and the levels of Na+ and Cl- were lower in the BC group. No between-group difference exists in creatinine level and vasopressor requirement. CONCLUSIONS: Perioperative balanced crystalloids can maintain the stability of acid-base and electrolyte balance and reduce acidosis compared with saline, but they cannot reduce postoperative renal insufficiency and mortality.

Adverse drug reactions in paediatric surgery: prospective study on frequency and risk related factors.

BACKGROUND: Paediatric patients are especially prone to experiencing adverse drug reactions (ADRs), and the surgical environment gathers many conditions for such reactions to occur. Additionally, little information exists in the literature on ADRs in the paediatric surgical population. We aimed to quantify the ADR frequency in this population, and to investigate the characteristics and risk factors associated with ADR development. METHODS: A prospective observational study was conducted in a cohort of 311 paediatric patients, aged 1-16 years, admitted for surgery at a tertiary referral hospital in Spain (2019-2021). Incidence rates were used to assess ADR frequency. Odds ratios (ORs) were calculated to evaluate the influence of potential risk factors on ADR development. RESULTS: Distinct ADRs (103) were detected in 80 patients (25.7%). The most frequent being hypotension (N = 32; 35%), nausea (N = 16; 15.5%), and emergence delirium (N = 16; 15.5%). Most ADRs occurred because of drug-drug interactions. The combination of sevoflurane and fentanyl was responsible for most of these events (N = 32; 31.1%). The variable most robustly associated to ADR development, was the number of off-label drugs prescribed per patient (OR = 2.99; 95% CI 1.73 to 5.16), followed by the number of drugs prescribed per patient (OR = 1.26, 95% CI 1.13 to 1.41), and older age (OR = 1.26, 95% CI 1.07 to 1.49). The severity of ADRs was assessed according to the criteria of Venulet and the Spanish Pharmacovigilance System. According to both methods, only four ADRs (3.9%) were considered serious. CONCLUSIONS: ADRs have a high incidence rate in the paediatric surgical population. The off-label use of drugs is a key risk factor for ADRs development.

Patient information leaflets for placebo-controlled surgical trials: a review of current practice and recommendations for developers.

INTRODUCTION: Informed consent for participation in an RCT is an important ethical and legal requirement. In placebo surgical trials, further issues are raised, and to date, this has not been explored. Patient information leaflets (PILs) are a core component of the informed consent process. This study aimed to investigate the key content of PILs for recently completed placebo-controlled trials of invasive procedures, including surgery, to highlight areas of good practice, identify gaps in information provision for trials of this type and provide recommendations for practice. METHODS: PILs were sought from trials included in a recent systematic review of placebo-controlled trials of invasive procedures, including surgery. Trial characteristics and data on surgical and placebo interventions under evaluation were extracted. Directed content analysis was applied, informed by published regulatory and good practice guidance on PIL content and existing research on placebo-controlled surgical trials. Results were analysed using descriptive statistics and presented as a narrative summary. RESULTS: Of the 62 eligible RCTs, authors of 59 trials were contactable and 14 PILs were received for analysis. At least 50% of all PILs included content on general trial design. Explanations of how the placebo differs or is similar to the surgical intervention (i.e. fidelity) were reported in 6 (43%) of the included PILs. Over half (57%) of the PILs included information on the potential therapeutic benefits of the surgical intervention. One (7%) included information on potential indirect therapeutic benefits from invasive components of the placebo. Five (36%) presented the known risks of the placebo intervention, whilst 8 (57%) presented information on the known risks of the surgical intervention. A range of terms was used across the PILs to describe the placebo component, including 'control', 'mock' and 'sham'. CONCLUSION: Developers of PILs for placebo-controlled surgical trials should carefully consider the use of language (e.g. sham, mock), be explicit about how the placebo differs (or is similar) to the surgical intervention and provide balanced presentations of potential benefits and risks of the surgical intervention separately from the placebo. Further research is required to determine optimal approaches to design and deliver this information for these trials.

Addition of High-Sensitivity Troponin to Perioperative Risk Assessment Improves the Predictive Ability of Death in Non-Cardiac Surgery Patients. / Adição da Troponina Ultrassensível à Avaliação de Risco Perioperatório Melhora a Capacidade Preditiva de Morte em Pacientes Submetidos à Cirurgia Não Cardíaca.

BACKGROUND: Risk stratification is an important step in perioperative evaluation. However, the main risk scores do not incorporate biomarkers in their set of variables. OBJECTIVE: Evaluate the incremental power of troponin to the usual risk stratification. METHODS: A total of 2,230 patients admitted to the intensive care unit after non-cardiac surgery were classified according to three types of risk: cardiovascular risk (CVR), Revised Cardiac Risk Index (RCRI); and inherent risk of surgery (IRS). The main outcome was all-cause mortality. Cox regression was used as well as c-statistics before and after addition of high-sensitivity troponin (at least one measurement up to three days after surgery). Finally, net reclassification index and integrated discrimination improvement were used to assess the incremental power of troponin for risk stratification. Significance level was set at 0.05. RESULTS: Mean age of patients was 63.8 years and 55.6% were women. The prevalence of myocardial injury after non-cardiac surgery (MINS) was 9.4%. High CVR-patients had a higher occurrence of MINS (40.1 x 24.8%, p<0.001), as well as high IRS-patients (21.3 x 13.9%, p=0.004) and those with a RCRI≥3 (3.0 x 0.7%, p=0.009). Patients without MINS, regardless of the assessed risk, had similar mortality rate. The addition of troponin to the risk assessment improved the predictive ability of death at 30 days and at 1 year in all risk assessments. CONCLUSION: The prevalence of MINS is higher in the high-risk population. However, its prevalence in lower-risk population is not negligible and causes a higher risk of death. The addition of high-sensitivity troponin increased the predictive ability of risk assessment in all groups.

FUNDAMENTO: A estratificação ode risco é uma importante etapa na avaliação perioperatória. No entanto, os principais escores de risco não incorporam biomarcadores em seus conjuntos de variáveis. OBJETIVO: Avaliar o poder incremental da troponina à estratificação de risco tradicional. MÉTODOS: Um total de 2230 pacientes admitidos na unidade de terapia intensiva após cirurgia não cardíaca foram classificados de acordo com três tipos de risco: Risco Cardiovascular (RCV), Índice de Risco Cardíaco Revisado (IRCR), e Risco Inerente da Cirurgia (RIC). O principal desfecho foi mortalidade por todas as causas. A regressão de Cox foi usada, assim como a estatística C antes e após a adição de troponina ultrassensível (pelo menos uma medida até três dias após a cirurgia). Finalmente, o índice de reclassificação líquida e a melhoria de discriminação integrada foram usadas para avaliar o poder incremental da troponina para a estratificação de risco. O nível de significância usado foi de 0,05. RESULTADOS: A idade média dos pacientes foi 63,8 anos e 55,6% eram do sexo feminino. A prevalência de lesão miocárdica após cirurgia não cardíaca (MINS) foi 9,4%. Pacientes com um RCV elevado apresentaram uma maior ocorrência de MINS (40,1% x 24,8%, p<0,001), bem como pacientes com alto RIC (21,3 x 13,9%, p=0,004) e aqueles com IRCR≥3 (3,0 x 0,7%, p=0,009). Pacientes sem MINS, independentemente do risco avaliado, apresentaram taxa de mortalidade similar. A adição de troponina à avaliação de risco melhorou a capacidade preditiva de mortalidade em 30 dias e de mortalidade em um ano em todas as avaliações de risco. CONCLUSÃO: A prevalência de MINS é mais alta na população de alto risco. No entanto, sua prevalência na população de risco mais baixo não é desprezível e causa um maior risco de morte. A adição da troponina ultrassensível melhorou a capacidade preditiva da avaliação de risco em todos os grupos.

Effect of Fluid Therapy in Early Morning on the Incidence of Post-Induction Hypotension During Non-Cardiac Surgery After Noon: A Single-Center Retrospective Study.

Purpose: Post-induction hypotension (PIH) is a common clinical phenomenon linked to increased morbidity and mortality in various non-cardiac surgeries. Patients with surgery in the afternoon may have preoperative hypovolemia caused by prolonged fasting and dehydration, which increases the risk of hypotension during the induction period. However, studies on the fluid therapy in early morning combating PIH remain inadequate. Therefore, we aimed to investigate the influence of prophylactic high-volume fluid in the early morning of the operation day on the incidence of PIH during non-cardiac surgery after noon. Patients and Methods: We reviewed the medical records of patients who underwent non-cardiac surgery after noon between October 2021 and October 2022. The patients were divided into two groups based on whether they received a substantial volume of intravenous fluid (high-volume group) or not (low-volume group) in the early morning of the surgery day. We investigated the incidence of PIH and intraoperative hypotension (IOH) as well as the accumulated duration of PIH in the first 15 minutes. In total, 550 patients were included in the analysis. Results: After propensity score matching, the incidence of PIH was 39.7% in the high-volume group and 54.1% in the low-volume group. Multivariate logistic regression analysis showed that patients in the high-volume group had lower incidence of hypotension after induction compared with the low-volume group (odds ratio, 0.55; 95% CI, 0.34-0.89; p = 0.016). The high-volume fluid infusion in the preoperative morning was significantly correlated with the decreased duration of PIH (p = 0.013), but no statistical difference was observed for the occurrence of IOH between the two groups (p = 0.075). Conclusion: The fluid therapy of more than or equal to 1000 mL in the early morning of the surgery day was associated with a decreased incidence of PIH compared with the low-volume group in patients undergoing non-cardiac surgery after noon.

Association of preoperative beta-blocker use and cardiac complications after major noncardiac surgery: a prospective cohort study.

INTRODUCTION: Cardiac complications after major noncardiac surgery are common and associated with high morbidity and mortality. How preoperative use of beta-blockers may impact perioperative cardiac complications remains unclear. METHODS: In a multicentre prospective cohort study, preoperative beta-blocker use was ascertained in consecutive patients at elevated cardiovascular risk undergoing major noncardiac surgery. Cardiac complications were prospectively monitored and centrally adjudicated by two independent experts. The primary endpoint was perioperative myocardial infarction or injury attributable to a cardiac cause (cardiac PMI) within the first three postoperative days. The secondary endpoints were major adverse cardiac events (MACE), defined as a composite of myocardial infarction, acute heart failure, life-threatening arrhythmia, and cardiovascular death and all-cause death after 365 days. We used inverse probability of treatment weighting to account for differences between patients receiving beta-blockers and those who did not. RESULTS: A total of 3839/10 272 (37.4%) patients (mean age 74 yr; 44.8% female) received beta-blockers before surgery. Patients on beta-blockers were older, and more likely to be male with established cardiorespiratory and chronic kidney disease. Cardiac PMI occurred in 1077 patients, with a weighted odds ratio of 1.03 (95% confidence interval [CI] 0.94-1.12, P=0.55) for patients on beta-blockers. Within 365 days of surgery, 971/10 272 (9.5%) MACE had occurred, with a weighted hazard ratio of 0.99 (95% CI 0.83-1.18, P=0.90) for patients on beta-blockers. CONCLUSION: Preoperative use of beta-blockers was not associated with decreased cardiac complications including cardiac perioperative myocardial infarction or injury and major adverse cardiac event. Additionally, preoperative use of beta-blockers was not associated with increased all-cause death within 30 and 365 days. CLINICAL TRIAL REGISTRATION: NCT02573532.

Impact of perioperative low-molecular-weight heparin therapy on clinical events of elderly patients with prior coronary stents implanted > 12 months undergoing non-cardiac surgery: a randomized, placebo-controlled trial.

BACKGROUND: Little is known about the safety and efficacy of discontinuing antiplatelet therapy via LMWH bridging therapy in elderly patients with coronary stents implanted for > 12 months undergoing non-cardiac surgery. This randomized trial was designed to compare the clinical benefits and risks of antiplatelet drug discontinuation via LMWH bridging therapy. METHODS: Patients were randomized 1:1 to receive subcutaneous injections of either dalteparin sodium or placebo. The primary efficacy endpoint was cardiac or cerebrovascular events. The primary safety endpoint was major bleeding. RESULTS: Among 2476 randomized patients, the variables (sex, age, body mass index, comorbidities, medications, and procedural characteristics) and percutaneous coronary intervention information were not significantly different between the bridging and non-bridging groups. During the follow-up period, the rate of the combined endpoint in the bridging group was significantly lower than in the non-bridging group (5.79% vs. 8.42%, p = 0.012). The incidence of myocardial injury in the bridging group was significantly lower than in the non-bridging group (3.14% vs. 5.19%, p = 0.011). Deep vein thrombosis occurred more frequently in the non-bridging group (1.21% vs. 0.4%, p = 0.024), and there was a trend toward a higher rate of pulmonary embolism (0.32% vs. 0.08%, p = 0.177). There was no significant difference between the groups in the rates of acute myocardial infarction (0.81% vs. 1.38%), cardiac death (0.24% vs. 0.41%), stroke (0.16% vs. 0.24%), or major bleeding (1.22% vs. 1.45%). Multivariable analysis showed that LMWH bridging, creatinine clearance < 30 mL/min, preoperative hemoglobin < 10 g/dL, and diabetes mellitus were independent predictors of ischemic events. LMWH bridging and a preoperative platelet count of < 70 × 109/L were independent predictors of minor bleeding events. CONCLUSIONS: This study showed the safety and efficacy of perioperative LMWH bridging therapy in elderly patients with coronary stents implanted > 12 months undergoing non-cardiac surgery. An alternative approach might be the use of bridging therapy with half-dose LMWH. TRIAL REGISTRATION: ISRCTN65203415.

Perioperative Risk of Noncardiac Surgery in Patients With Asymptomatic Significant Aortic Stenosis: A 10-Year Retrospective Study.

BACKGROUND: Aortic stenosis (AS) is a representative geriatric disease, and there is an anticipated rise in the number of patients requiring noncardiac surgeries in patients with AS. However, there is still a lack of research on the primary predictors of noncardiac perioperative complications in patients with asymptomatic significant AS. METHODS AND RESULTS: Among the cohort of noncardiac surgeries under general anesthesia, with an intermediate to high risk of surgery from 2011 to 2019, at Samsung Medical Center, 221 patients were identified to have asymptomatic significant AS. First, to examine the impact of significant AS on perioperative adverse events, the occurrences of major adverse cardiovascular events and perioperative adverse cardiovascular events were compared between patients with asymptomatic significant AS and the control group. Second, to identify the factors influencing the perioperative adverse events in patients with asymptomatic significant AS, a least absolute shrinkage and selection operator regression model was used. There was no significant difference between the control group and the asymptomatic significant AS group in the event rate of major adverse cardiovascular events (4.6% at control group versus 5.5% at asymptomatic significant AS group; P=0.608) and perioperative adverse cardiovascular events (13.8% at control group versus 18.3% at asymptomatic significant AS group; P=0.130). Cardiac damage stage was a significant risk factor of major adverse cardiovascular events and perioperative adverse cardiovascular events. CONCLUSIONS: There was no significant difference in major postoperative cardiovascular events between patients with asymptomatic significant AS and the control group. Advanced cardiac damage stage in significant AS is an important factor in perioperative risk of noncardiac surgery.

A Mediation Analysis Examining High Risk, Anticholinergic Medication Use, Delirium, and Dementia After Major Surgery.

INTRODUCTION: Anticholinergic medications are known to cause adverse cognitive effects in community-dwelling older adults and medical inpatients, including dementia. The prevalence with which such medications are prescribed in older adults undergoing major surgery is not well described nor is their mediating relationship with delirium and dementia. We sought to determine the prevalence of high-risk medication use in major surgery patients and their relationship with the subsequent development of dementia. METHODS: This was a retrospective cohort study which used data between January 2013 and December 2019, in a large midwestern health system, including sixteen hospitals. All patients over age 50 undergoing surgery requiring an inpatient stay were included. The primary exposure was the number of doses of anticholinergic medications delivered during the hospital stay. The primary outcome was a new diagnosis of Alzheimer's disease and related dementias at 1-y postsurgery. Regression methods and a mediation analysis were used to explore relationships between anticholinergic medication usage, delirium, and dementia. RESULTS: There were 39,665 patients included, with a median age of 66. Most patients were exposed to anticholinergic medications (35,957/39,665; 91%), and 7588/39,665 (19.1%) patients received six or more doses during their hospital stay. Patients with at least six doses of these medications were more likely to be female, black, and with a lower American Society of Anesthesiologists class. Upon adjusted analysis, high doses of anticholinergic medications were associated with increased odds of dementia at 1 y relative to those with no exposure (odds ratio 2.7; 95% confidence interval 2.2-3.3). On mediation analysis, postoperative delirium mediated the effect of anticholinergic medications on dementia, explaining an estimated 57.6% of their association. CONCLUSIONS: High doses of anticholinergic medications are common in major surgery patients and, in part via a mediating relationship with postoperative delirium, are associated with the development of dementia 1 y following surgery. Strategies to decrease the use of these medications and encourage the use of alternatives may improve long-term cognitive recovery.

Postoperative haemoglobin and anaemia-associated ischaemic events after major noncardiac surgery: A sex-stratified cohort study.

STUDY OBJECTIVE: To determine the sex-specific associations between postoperative haemoglobin and mortality or complications reflecting ischaemia or inadequate oxygen supply after major noncardiac surgery. DESIGN: A retrospective cohort study with prospective validation. SETTING: A large university hospital health system in China. PATIENTS: Men and women undergoing elective major noncardiac surgery. INTERVENTIONS AND MEASUREMENTS: The primary exposure was nadir haemoglobin within 48 h after surgery. The outcome of interest was a composite of postoperative mortality or ischaemic events including myocardial injury, acute kidney injury and stroke within hospitalisation. MAIN RESULTS: The study included 26,049 patients (15,757 men and 10,292 women). Low postoperative haemoglobin was a strong predictor of the composite outcome in both sexes, with the risk progressively increasing as the nadir haemoglobin concentration dropped below 130 g l-1 in men and 120 g l-1 in women (adjusted odds ratio [OR] 1.43, 95% CI 1.37-1.50 in men, and OR 1.45, 95% CI 1.35-1.55 in women, per 10 g l-1 decrease in postoperative nadir haemoglobin). Above these sex-specific thresholds, the change of nadir haemoglobin was no longer associated with odds of the composite outcome in either men or women. There was no significant interaction between patient sex and the association between postoperative haemoglobin and the composite outcome (Pinteraction = 0.673). Validation in an external prospective cohort (n = 2120) with systematic postoperative troponin and creatinine measurement confirmed our findings. CONCLUSIONS: Postoperative haemoglobin levels following major noncardiac surgery were nonlinearly associated with ischaemic complications or mortality, without any clinically important interaction with patient sex.

Development and validation of a novel score for predicting perioperative major adverse cardiovascular events in patients with stable coronary artery disease undergoing noncardiac surgery.

BACKGROUND: A model developed specifically for stable coronary artery disease (SCAD) patients to predict perioperative major adverse cardiovascular events (MACE) has not been previously reported. METHODS: The derivation cohort consisted of 5780 patients with SCAD undergoing noncardiac surgery at the First Affiliated Hospital of Zhejiang University School of Medicine, from January 1, 2013 until May 31, 2021. The validation cohort consisted of 2677 similar patients from June 1, 2021 to May 31, 2023. The primary outcome was a composite of MACEs (death, resuscitated cardiac arrest, myocardial infarction, heart failure, and stroke) intraoperatively or during hospitalization postoperatively. RESULTS: Six predictors, including Creatinine >90 µmol/L, Hemoglobin <110 g/L, Albumin <40 g/L, Leukocyte >10 ×109/L, high-risk Surgery (general abdominal or vascular), and American Society of Anesthesiologists (ASA) class (III or IV), were selected in the final model (CHALSA score). Each patient was assigned a CHALSA score of 0, 1, 2, 3, or > 3 according to the number of predictors present. The incidence of perioperative MACEs increased steadily across the CHALSA score groups in both the derivation (0.5%, 1.4%, 2.9%, 6.8%, and 23.4%, respectively; p < 0.001) and validation (0.3%, 1.5%, 4.1%, 9.2%, and 29.2%, respectively; p < 0.001) cohorts. The CHALSA score had a higher discriminatory ability than the revised cardiac risk index (C statistic: 0.827 vs. 0.695 in the validation dataset; p < 0.001). CONCLUSIONS: The CHALSA score showed good validity in an external dataset and will be a valuable bedside tool to guide the perioperative management of patients with SCAD undergoing noncardiac surgery.

Metformin Use in Type 2 Diabetics and Delirium After Noncardiac Surgery: A Retrospective Cohort Analysis.

INTRODUCTION: The cause of postoperative delirium is unknown, but it is thought to result at least in part from inflammation. Metformin, besides its hypoglycemic properties, demonstrates anti-inflammatory effects systemically and in the brain. We tested the primary hypothesis that chronic metformin use in adults with type 2 diabetes is associated with less delirium during the first 5 days after major noncardiac surgery. Secondary outcomes were a composite of serious complications (myocardial infarction, cardiac arrest, stage 2-3 acute kidney injury [AKI], and mortality) and time to discharge alive. METHODS: We considered adults with type 2 diabetes who did or did not routinely use metformin daily and had noncardiac surgery. Delirium was assessed by Confusion Assessment Method for Intensive Care Unit (CAM-ICU) or brief Confusion Assessment Method (bCAM) for 5 postoperative days. Postoperative AKI was defined by Kidney Disease Improving Global Guidelines. Logistic regression and generalized estimating equation models accounted for within-patient correlation across multiple surgeries and explored the association between metformin use and postoperative delirium and complications. Inverse propensity score weighting and propensity score calibration (PSC) adjusted for confounding variables. RESULTS: No significant difference was observed in the incidence of postoperative delirium between the 2 groups, with 260 of 4744 cases (5.5%) among metformin users and 502 of 5918 cases (8.5%) cases in nonmetformin users, for an odds ratio of 0.88 (95% confidence interval [CI], 0.73-1.05; P = .155), number-needed-to-expose = 118 patients. Similarly, there were fewer composite complications in metformin users (3.3%) than in nonusers (11.7%); However, the common-effect odds ratio of 0.67 was not statistically significant (97.5% CI, 0.39-1.17; P = .106). Discharge from the hospital was significantly faster in patients who took metformin (3 [interquartile range, IQR, 1-5] days for metformin users and 3 [IQR, 2-6] days for nonmetformin users), with a hazard ratio of 1.07 for early discharge, and tight CIs (1.01-1.13). CONCLUSIONS: Chronic metformin use was associated with slightly and nonsignificantly less delirium. However, patients who used metformin had clinically meaningfully fewer major complications, mostly stage 2 to 3 kidney injury. While not statistically significant, the reduction was substantial and warrants further investigation because there is currently no effective preventive measure for perioperative renal injury. Benefit would be especially meaningful if it could be produced by acute perioperative treatment. Finally, metformin was associated with faster hospital discharge, although not by a clinically meaningful amount.

Development of interpretable machine learning models for prediction of acute kidney injury after noncardiac surgery: a retrospective cohort study.

BACKGROUND: Early identification of patients at high-risk of postoperative acute kidney injury (AKI) can facilitate the development of preventive approaches. This study aimed to develop prediction models for postoperative AKI in noncardiac surgery using machine learning algorithms. The authors also evaluated the predictive performance of models that included only preoperative variables or only important predictors. MATERIALS AND METHODS: Adult patients undergoing noncardiac surgery were retrospectively included in the study (76 457 patients in the discovery cohort and 11 910 patients in the validation cohort). AKI was determined using the KDIGO criteria. The prediction model was developed using 87 variables (56 preoperative variables and 31 intraoperative variables). A variety of machine learning algorithms were employed to develop the model, including logistic regression, random forest, extreme gradient boosting, and gradient boosting decision trees. The performance of different models was compared using the area under the receiver operating characteristic curve (AUROC). Shapley Additive Explanations (SHAP) analysis was employed for model interpretation. RESULTS: The patients in the discovery cohort had a median age of 52 years (IQR: 42-61 years), and 1179 patients (1.5%) developed AKI after surgery. The gradient boosting decision trees algorithm showed the best predictive performance using all available variables, or only preoperative variables. The AUROCs were 0.849 (95% CI: 0.835-0.863) and 0.828 (95% CI: 0.813-0.843), respectively. The SHAP analysis showed that age, surgical duration, preoperative serum creatinine, and gamma-glutamyltransferase, as well as American Society of Anesthesiologists physical status III were the most important five features. When gradually reducing the features, the AUROCs decreased from 0.852 (including the top 40 features) to 0.839 (including the top 10 features). In the validation cohort, the authors observed a similar pattern regarding the models' predictive performance. CONCLUSIONS: The machine learning models the authors developed had satisfactory predictive performance for identifying high-risk postoperative AKI patients. Furthermore, the authors found that model performance was only slightly affected when only preoperative variables or only the most important predictive features were included.

Multicentre validation of a machine learning model for predicting respiratory failure after noncardiac surgery.

BACKGROUND: Postoperative respiratory failure is a serious complication that could benefit from early accurate identification of high-risk patients. We developed and validated a machine learning model to predict postoperative respiratory failure, defined as prolonged (>48 h) mechanical ventilation or reintubation after surgery. METHODS: Easily extractable electronic health record (EHR) variables that do not require subjective assessment by clinicians were used. From EHR data of 307,333 noncardiac surgical cases, the model, trained with a gradient boosting algorithm, utilised a derivation cohort of 99,025 cases from Seoul National University Hospital (2013-9). External validation was performed using three separate cohorts A-C from different hospitals comprising 208,308 cases. Model performance was assessed by area under the receiver operating characteristic (AUROC) curve and area under the precision-recall curve (AUPRC), a measure of sensitivity and precision at different thresholds. RESULTS: The model included eight variables: serum albumin, age, duration of anaesthesia, serum glucose, prothrombin time, serum creatinine, white blood cell count, and body mass index. Internally, the model achieved an AUROC of 0.912 (95% confidence interval [CI], 0.908-0.915) and AUPRC of 0.113. In external validation cohorts A, B, and C, the model achieved AUROCs of 0.879 (95% CI, 0.876-0.882), 0.872 (95% CI, 0.870-0.874), and 0.931 (95% CI, 0.925-0.936), and AUPRCs of 0.029, 0.083, and 0.124, respectively. CONCLUSIONS: Utilising just eight easily extractable variables, this machine learning model demonstrated excellent discrimination in both internal and external validation for predicting postoperative respiratory failure. The model enables personalised risk stratification and facilitates data-driven clinical decision-making.

Anesthetic recommendations for maternal and fetal safety in nonobstetric surgery: a balancing act.

PURPOSE OF REVIEW: Nonobstetric surgery during pregnancy is associated with maternal and fetal risks. Several physiologic changes create unique challenges for anesthesiologists. This review highlights physiologic changes of pregnancy and presents clinical recommendations based on recent literature to guide anesthetic management for the pregnant patient undergoing nonobstetric surgery. RECENT FINDINGS: Nearly every anesthetic technique has been safely used in pregnant patients. Although it is difficult to eliminate confounding factors, exposure to anesthetics could endanger fetal brain development. Perioperative fetal monitoring decisions require an obstetric consult based on anticipated maternal and fetal concerns. Given the limitations of fasting guidelines, bedside gastric ultrasound is useful in assessing aspiration risk in pregnant patients. Although there is concern about appropriateness of sugammadex for neuromuscular blockade reversal due its binding to progesterone, preliminary literature supports its safety. SUMMARY: These recommendations will equip anesthesiologists to provide safe care for the pregnant patient and fetus undergoing nonobstetric surgery.