A Randomized Trial of Intravenous Amino Acids for Kidney Protection.

BACKGROUND: Acute kidney injury (AKI) is a serious and common complication of cardiac surgery, for which reduced kidney perfusion is a key contributing factor. Intravenous amino acids increase kidney perfusion and recruit renal functional reserve. However, the efficacy of amino acids in reducing the occurrence of AKI after cardiac surgery is uncertain. METHODS: In a multinational, double-blind trial, we randomly assigned adult patients who were scheduled to undergo cardiac surgery with cardiopulmonary bypass to receive an intravenous infusion of either a balanced mixture of amino acids, at a dose of 2 g per kilogram of ideal body weight per day, or placebo (Ringer's solution) for up to 3 days. The primary outcome was the occurrence of AKI, defined according to the Kidney Disease: Improving Global Outcomes creatinine criteria. Secondary outcomes included the severity of AKI, the use and duration of kidney-replacement therapy, and all-cause 30-day mortality. RESULTS: We recruited 3511 patients at 22 centers in three countries and assigned 1759 patients to the amino acid group and 1752 to the placebo group. AKI occurred in 474 patients (26.9%) in the amino acid group and in 555 (31.7%) in the placebo group (relative risk, 0.85; 95% confidence interval [CI], 0.77 to 0.94; P = 0.002). Stage 3 AKI occurred in 29 patients (1.6%) and 52 patients (3.0%), respectively (relative risk, 0.56; 95% CI, 0.35 to 0.87). Kidney-replacement therapy was used in 24 patients (1.4%) in the amino acid group and in 33 patients (1.9%) in the placebo group. There were no substantial differences between the two groups in other secondary outcomes or in adverse events. CONCLUSIONS: Among adult patients undergoing cardiac surgery, infusion of amino acids reduced the occurrence of AKI. (Funded by the Italian Ministry of Health; PROTECTION ClinicalTrials.gov number, NCT03709264.).

Preoperative anemia and anemia treatment in cardiac surgery: a systematic review and meta-analysis.

PURPOSE: We aimed to conduct a systematic review and meta-analysis to assess the effects of anemia and anemia severity on patient outcomes in cardiac surgery and determine whether preoperative treatments confer postoperative benefit. SOURCE: We searched four international databases for observational and randomized studies published until 1 October 2022. Study quality was assessed via Newcastle-Ottawa scores and the Cochrane Risk-of-Bias 2 tool and certainty of evidence was rated with the Grading of Recommendations, Assessment, Development and Evaluations approach. We conducted random-effects meta-analyses for our primary outcome of mortality, for secondary outcomes including length of stay (LOS) in the hospital and intensive care unit, and for postsurgical complications. As part of a secondary analysis, we analyzed short-term preoperative anemia treatments and conducted trial sequential analysis of randomized trials to assess the efficacy of these treatment programs. PRINCIPAL FINDINGS: We included 35 studies (159,025 patients) in our primary meta-analysis. Preoperative anemia was associated with increased mortality (odds ratio [OR], 2.5; 95% confidence interval [CI], 2.2 to 2.9; P < 0.001, high certainty). Study-level meta-regression revealed lower hemoglobin levels and studies with lower proportions of male patients to be associated with increased risk of mortality. Preoperative anemia was also associated with an increase in LOS and postsurgical complications. Our secondary analysis (seven studies, 1,012 patients) revealed short-term preoperative anemia treatments did not significantly reduce mortality (OR, 1.1; 95% CI, 0.65 to 1.9; P = 0.69). Trial sequential analysis suggested that there was insufficient evidence to conclude if treatment programs yield any benefit or harm. CONCLUSIONS: Preoperative anemia is associated with mortality and morbidity after cardiac surgery. More research is warranted to test the efficacy of current anemia treatment programs. STUDY REGISTRATION: PROSPERO (CRD42022319431); first submitted 17 April 2023.

RéSUMé: OBJECTIF: Notre objectif était de mener une revue systématique et une méta-analyse pour évaluer les effets de l'anémie et de la gravité de l'anémie sur les devenirs des patient·es en chirurgie cardiaque et déterminer si les traitements préopératoires conféraient un bénéfice postopératoire. SOURCES: Nous avons réalisé des recherches dans quatre bases de données internationales pour en extraire des études observationnelles et randomisées publiées jusqu'au 1er octobre 2022. La qualité des études a été évaluée à l'aide des scores de Newcastle-Ottawa et de l'outil Cochrane 2 sur le risque de biais, et la certitude des données probantes a été évaluée selon l'approche GRADE (Grading of Recommendations, Assessment, Development and Evaluations). Nous avons réalisé des méta-analyses à effets aléatoires pour notre critère d'évaluation principal de mortalité, pour les critères d'évaluation secondaires, notamment la durée du séjour à l'hôpital et à l'unité de soins intensifs, et pour les complications postopératoires. Dans le cadre d'une analyse secondaire, nous avons examiné les traitements préopératoires de l'anémie à court terme et effectué une analyse séquentielle d'études randomisées afin d'évaluer l'efficacité de ces modalités de traitement. CONSTATATIONS PRINCIPALES: Nous avons inclus 35 études portant sur 159 025 patient·es dans notre méta-analyse. L'anémie préopératoire était associée à une augmentation de la mortalité (rapport de cotes [RC], 2,5; intervalle de confiance [IC] à 95 %, 2,2 à 2,9; P < 0,001, certitude élevée). La méta-régression au niveau de l'étude a révélé que des taux d'hémoglobine plus faibles et des études avec des proportions plus faibles de patients masculins étaient associées à un risque accru de mortalité. L'anémie préopératoire était également associée à une augmentation de la durée de séjour et des complications postopératoires. Notre analyse secondaire (sept études, 1012 patient·es) a révélé que les traitements préopératoires de l'anémie à court terme ne réduisaient pas significativement la mortalité (RC, 1,1; IC 95 %, 0,65 à 1,9; P = 0,69). L'analyse séquentielle des études a suggéré qu'il n'y avait pas suffisamment de données probantes pour conclure si les modalités de traitement entraînaient un bénéfice ou un préjudice. CONCLUSION: L'anémie préopératoire est associée à la mortalité et à la morbidité après une chirurgie cardiaque. D'autres recherches sont justifiées pour tester l'efficacité des programmes actuels de traitement de l'anémie. ENREGISTREMENT DE L'éTUDE: PROSPERO (CRD42022319431); première soumission le 17 avril 2023.

Feasibility of continuous non-invasive delivery of oxygen monitoring in cardiac surgical patients: a proof-of-concept preliminary study.

PURPOSE: Oxygen delivery (DO2) and its monitoring are highlighted to aid postoperative goal directed therapy (GDT) to improve perioperative outcomes such as acute kidney injury (AKI) after high-risk cardiac surgeries associated with multiple morbidities and mortality. However, DO2 monitoring is neither routine nor done postoperatively, and current methods are invasive and only produce intermittent DO2 trends. Hence, we proposed a novel algorithm that simultaneously integrates cardiac output (CO), hemoglobin (Hb) and oxygen saturation (SpO2) from the Edwards Life Sciences ClearSight System® and Masimo SET Pulse CO-Oximetry® to produce a continuous, real-time DO2 trend. METHODS: Our algorithm was built systematically with 4 components - machine interface to draw data with PuTTY, data extraction with parsing, data synchronization, and real-time DO2 presentation using a graphic-user interface. Hb readings were validated. RESULTS: Our algorithm was implemented successfully in 93% (n = 57 out of 61) of our recruited cardiac surgical patients. DO2 trends and AKI were studied. CONCLUSION: We demonstrated a novel proof-of-concept and feasibility of continuous, real-time, non-invasive DO2 monitoring, with each patient serving as their own control. Our study also lays the foundation for future investigations aimed at identifying personalized critical DO2 thresholds and optimizing DO2 as an integral part of GDT to enhance outcomes in perioperative cardiac surgery.

Paramedian versus midline approach of spinal anesthesia: a systematic review and meta-analysis with trial sequential analysis.

PURPOSE: Midline approach of spinal anesthesia has been widely used for patients undergoing surgical procedures. However, it might not be effective for obstetric patients and elderly with degenerative spine changes. Primary objective was to examine the success rate at the first attempt between the paramedian and midline spinal anesthesia in adults undergoing surgery. METHODS: Databases of MEDLINE, EMBASE, and CENTRAL were searched from their starting date until February 2023. Randomized clinical trials (RCTs) comparing the paramedian versus midline approach of spinal anesthesia were included. The primary outcome was the success rate at the first attempt of spinal anesthesia. RESULTS: Our review included 36 RCTs (n = 5379). Compared to the midline approach, paramedian approach may increase success rate at the first attempt but the evidence is very uncertain (OR: 0.47, 95% CI 0.27-0.82, ρ = 0.007, level of evidence:very low). Our pooled data indicates that the paramedian approach likely reduced incidence of post-spinal headache (OR: 2.07, 95% CI 1.51-2.84, ρ < 0.00001, level of evidence:moderate). The evidence suggests that the paramedian approach may result in a reduction in the occurrence of paresthesia (OR: 1.61, 95% CI 1.06-2.45, ρ = 0.03, level of evidence:low). CONCLUSIONS: Our meta-analysis of 36 RCTs showed that paramedian approach may result in little to no difference in success rate at the first attempt owing to its very low level of evidence. However, given the low level of evidence and studies with small sample sizes, these findings need to be interpreted with caveat. CLINICAL TRIAL REGISTRATION NUMBER: CRD42023397781.

Thoracic Epidural Anesthesia in Cardiac Surgery: A Systematic Review, Meta-Analysis, and Trial Sequential Analysis of Randomized Controlled Trials.

BACKGROUND: Research on fast-track recovery protocols postulates that thoracic epidural anesthesia (TEA) in cardiac surgery contributes to improved postoperative outcomes. However, concerns about TEA's safety hinder its widespread usage. We conducted a systematic review and meta-analysis to assess the benefits and risks of TEA in cardiac surgery. METHODS: We searched 4 databases for randomized controlled trials (RCTs) assessing the use of TEA against only general anesthesia (GA) in adults undergoing cardiac surgery, up till June 4, 2022. We conducted random-effects meta-analyses, evaluated risk of bias using the Cochrane Risk-of-Bias 2 tool, and rated certainty of evidence via the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach. Primary outcomes were intensive care unit (ICU), hospital length of stay, extubation time (ET), and mortality. Other outcomes included postoperative complications. Trial sequential analysis (TSA) was conducted on all outcomes to elicit statistical and clinical benefit. RESULTS: Our meta-analysis included 51 RCTs (2112 TEA patients and 2220 GA patients). TEA significantly reduced ICU length of stay (-6.9 hours; 95% confidence interval [CI], -12.5 to -1.2; P = .018), hospital length of stay (-0.8 days; 95% CI, -1.1 to -0.4; P < .0001), and ET (-2.9 hours; 95% CI, -3.7 to -2.0; P < .0001). However, we found no significant change in mortality. TSA found that the cumulative Z-curve passed the TSA-adjusted boundary for ICU length of stay, hospital length of stay, and ET, suggesting a clinical benefit. TEA also significantly reduced pain scores, pooled pulmonary complications, transfusion requirements, delirium, and arrhythmia, without additional complications such as epidural hematomas, of which the risk was estimated to be <0.14%. CONCLUSIONS: TEA reduces ICU and hospital length of stay, and postoperative complications in patients undergoing cardiac surgery with minimal reported complications such as epidural hematomas. These findings favor the use of TEA in cardiac surgery and warrant consideration for use in cardiac surgeries worldwide.

Non-invasive mid-term electrocardiogram patch monitoring is effective in detecting atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a cause of serious morbidity such as stroke. Early detection and treatment of AF is important. Current guidelines recommend screening via opportunistic pulse taking or 12­lead electrocardiogram. Mid-term ECG patch monitors increases the sensitivity of AF detection. METHODS: The Singapore Atrial Fibrillation Study is a prospective multi-centre study aiming to study the incidence of AF in patients with no prior AF and a CHA2DS2-VASc score of at least 1, with the use of a mid-term continuous ECG monitoring device (Spyder ECG). Consecutive patients from both inpatient and outpatient settings were recruited from 3 major hospitals from May 2016 to December 2019. RESULTS: Three hundred and fifty-five patients were monitored. 6 patients (1.7%) were diagnosed with AF. There were no significant differences in total duration of monitoring between the AF and non-AF group (6.39 ± 3.19 vs 5.42 ± 2.46 days, p = 0.340). Patients with newly detected AF were more likely to have palpitations (50.0% vs 11.8%, p = 0.027). Half of the patients (n = 3, 50.0%) were diagnosed on the first day of monitoring and the rest were diagnosed after 24 h. On univariate analysis, only hyperlipidemia was associated with reduced odds of being diagnosed with AF (OR HR 0.08 CI 0.01-0.74, p = 0.025). In a group of 128 patients who underwent coronary artery bypass grafting and had post-operative ECG monitoring, 9 patients (7.0%) were diagnosed with post-operative AF. CONCLUSIONS: The use of non-invasive mid-term patch-based ECG monitoring is an effective modality for AF screening.

Predictors of unplanned hospital readmission after non-cardiac surgery in Singapore: a 2-year retrospective review.

INTRODUCTION: Unplanned hospital readmissions after surgery contribute significantly to healthcare costs and potential complications. Identifying predictors of readmission is inherently complex and involves an intricate interplay between medical factors, healthcare system factors and sociocultural factors. Therefore, the aim of this study was to elucidate the predictors of readmissions in an Asian surgical patient population. METHODS: A two-year single-institution retrospective cohort study of 2744 patients was performed in a university-affiliated tertiary hospital in Singapore, including patients aged 45 and above undergoing intermediate or high-risk non-cardiac surgery. Unadjusted analysis was first performed, followed by multivariable logistic regression. RESULTS: Two hundred forty-nine patients (9.1%) had unplanned 30-day readmissions. Significant predictors identified from multivariable analysis include: American Society of Anaesthesiologists (ASA) Classification grades 3 to 5 (adjusted OR 1.51, 95% CI 1.10-2.08, p = 0.01), obesity (adjusted OR 1.66, 95% CI 1.18-2.34, p = 0.04), asthma (OR 1.70, 95% CI 1.03-2.81, p = 0.04), renal disease (OR 2.03, 95% CI 1.41-2.92, p < 0.001), malignancy (OR 1.68, 95% CI 1.29-2.37, p < 0.001), chronic obstructive pulmonary disease (OR 2.46, 95% CI 1.19-5.11, p = 0.02), cerebrovascular disease (OR 1.73, 95% CI 1.17-2.58, p < 0.001) and anaemia (OR 1.45, 95% CI 1.07-1.96, p = 0.02). CONCLUSION: Several significant predictors of unplanned readmissions identified in this Asian surgical population corroborate well with findings from Western studies. Further research will require future prospective studies and development of predictive risk modelling to further address and mitigate this phenomenon.

Association Between Race and Opioid-Induced Respiratory Depression: An International Post Hoc Analysis of the Prediction of Opioid-induced Respiratory Depression In Patients Monitored by Capnography Trial.

BACKGROUND: Opioid-induced respiratory depression (OIRD) is common on the medical and surgical wards and is associated with increased morbidity and health care costs. While previous studies have investigated risk factors for OIRD, the role of race remains unclear. We aim to investigate the association between race and OIRD occurrence on the medical/surgical ward. METHODS: This is a post hoc analysis of the PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) trial; a prospective multinational observational blinded study of 1335 general ward patients who received parenteral opioids and underwent blinded capnography and oximetry monitoring to identify OIRD episodes. For this study, demographic and perioperative data, including race and comorbidities, were analyzed and assessed for potential associations with OIRD. Univariable χ 2 and Mann-Whitney U tests were used. Stepwise selection of all baseline and demographic characteristics was used in the multivariable logistic regression analysis. RESULTS: A total of 1253 patients had sufficient racial data (317 Asian, 158 Black, 736 White, and 42 other races) for inclusion. The incidence of OIRD was 60% in Asians (N = 190/317), 25% in Blacks (N = 40/158), 43% in Whites (N = 316/736), and 45% (N = 19/42) in other races. Baseline characteristics varied significantly: Asians were older, more opioid naïve, and had higher opioid requirements, while Blacks had higher incidences of heart failure, obesity, and smoking. Stepwise multivariable logistic regression revealed that Asians had increased risk of OIRD compared to Blacks (odds ratio [OR], 2.49; 95% confidence interval [CI], 1.54-4.04; P = .0002) and Whites (OR, 1.38; 95% CI, 1.01-1.87; P = .0432). Whites had a higher risk of OIRD compared to Blacks (OR, 1.81; 95% CI, 1.18-2.78; P = .0067). The model's area under the curve was 0.760 (95% CI, 0.733-0.787), with a Hosmer-Lemeshow goodness-of-fit test P value of .23. CONCLUSIONS: This post hoc analysis of PRODIGY found a novel association between Asian race and increased OIRD incidence. Further study is required to elucidate its underlying mechanisms and develop targeted care pathways to reduce OIRD in susceptible populations.

Bispectral Index (BIS) Monitoring and Postoperative Delirium in Elderly Patients Undergoing Surgery: A Systematic Review and Meta-Analysis With Trial Sequential Analysis.

OBJECTIVE: To examine the effect of bispectral index (BIS)-guided anesthesia on the incidence of postoperative delirium (POD) in elderly patients undergoing surgery. DESIGN: A systematic review, meta-analysis, and trial sequential analysis (TSA). SETTING: In the operating room, postoperative anesthesia care units (PACU), and ward. PARTICIPANTS: Elderly patients (>60 years old) undergoing surgery. INTERVENTIONS: The EMBASE, MEDLINE, and CENTRAL databases were searched systematically from their inception until December 2020 for randomized controlled trials comparing BIS and usual care or blinded BIS. MEASUREMENTS AND MAIN RESULTS: Ten trials (N = 3,891) were included for quantitative meta-analysis. In comparison to the control group, there was no significant difference in the incidence of POD in elderly patients randomized to BIS-guided anesthesia (odds ratio [OR] 0.71, 95% CI 0.47-1.08, I2 = 76%, p = 0.11, level of evidence = very low, TSA = inconclusive). The authors' review demonstrated that elderly patients with BIS-guided anesthesia were significantly associated with a lower incidence of postoperative cognitive dysfunction (POCD) (OR 0.64, 95% CI 0.46-0.88, p = 0.006), extubation time (mean difference [MD] -3.38 minutes, 95% CI -4.38 to -2.39, p < 0.00001), time to eye opening (MD -2.17 minutes, 95% CI -4.21 to -0.14, p = 0.04), and time to discharge from the PACU (MD -10.77 minutes, 95% CI -11.31 to - 10.23, p < 0.00001). CONCLUSION: The authors' meta-analysis demonstrated that BIS-guided anesthesia was not associated with a reduced incidence of POD, but it was associated with a reduced incidence of POCD and improved recovery parameters.

Assessment of acute kidney injury risk using a machine-learning guided generalized structural equation model: a cohort study.

BACKGROUND: Acute kidney injury is common in the surgical intensive care unit (ICU). It is associated with poor patient outcomes and high healthcare resource usage. This study's primary objective is to help identify which ICU patients are at high risk for acute kidney injury. Its secondary objective is to examine the effect of acute kidney injury on a patient's prognosis during and after the ICU admission. METHODS: A retrospective cohort of patients admitted to a Singaporean surgical ICU between 2015 to 2017 was collated. Patients undergoing chronic dialysis were excluded. The outcomes were occurrence of ICU acute kidney injury, hospital mortality and one-year mortality. Predictors were identified using decision tree algorithms. Confirmatory analysis was performed using a generalized structural equation model. RESULTS: A total of 201/940 (21.4%) patients suffered acute kidney injury in the ICU. Low ICU haemoglobin levels, low ICU bicarbonate levels, ICU sepsis, low pre-ICU estimated glomerular filtration rate (eGFR) and congestive heart failure was associated with the occurrence of ICU acute kidney injury. Acute kidney injury, together with old age (> 70 years), and low pre-ICU eGFR, was associated with hospital mortality, and one-year mortality. ICU haemoglobin level was discretized into 3 risk categories for acute kidney injury: high risk (haemoglobin ≤9.7 g/dL), moderate risk (haemoglobin between 9.8-12 g/dL), and low risk (haemoglobin > 12 g/dL). CONCLUSION: The occurrence of acute kidney injury is common in the surgical ICU. It is associated with a higher risk for hospital and one-year mortality. These results, in particular the identified haemoglobin thresholds, are relevant for stratifying a patient's acute kidney injury risk.

Perioperative temperature management: a survey of 6 Asia-Pacific countries.

BACKGROUND: Anesthesia leads to impairments in central and peripheral thermoregulatory responses. Inadvertent perioperative hypothermia is hence a common perioperative complication, and is associated with coagulopathy, increased surgical site infection, delayed drug metabolism, prolonged recovery, and shivering. However, surveys across the world have shown poor compliance to perioperative temperature management guidelines. Therefore, we evaluated the prevalent practices and attitudes to perioperative temperature management in the Asia-Pacific region, and determined the individual and institutional factors that lead to noncompliance. METHODS: A 40-question anonymous online questionnaire was distributed to anesthesiologists and anesthesia trainees in six countries in the Asia-Pacific (Singapore, Malaysia, Philippines, Thailand, India and South Korea). Participants were polled about their current practices in patient warming and temperature measurement across the preoperative, intraoperative and postoperative periods. Questions were also asked regarding various individual and environmental barriers to compliance. RESULTS: In total, 1154 valid survey responses were obtained and analyzed. 279 (24.2%) of respondents prewarm, 508 (44.0%) perform intraoperative active warming, and 486 (42.1%) perform postoperative active warming in the majority of patients. Additionally, 531 (46.0%) measure temperature preoperatively, 767 (67.5%) measure temperature intraoperatively during general anesthesia, and 953 (82.6%) measure temperature postoperatively in the majority of patients. The availability of active warming devices in the operating room (p < 0.001, OR 10.040), absence of financial restriction (p < 0.001, OR 2.817), presence of hospital training courses (p = 0.011, OR 1.428), and presence of a hospital SOP (p < 0.001, OR 1.926) were significantly associated with compliance to intraoperative active warming. CONCLUSIONS: Compliance to international perioperative temperature management guidelines in Asia-Pacific remains poor, especially in small hospitals. Barriers to compliance were limited temperature management equipment, lack of locally-relevant standard operating procedures and training. This may inform international guideline committees on the needs of developing countries, or spur local anesthesiology societies to publish their own national guidelines.

Opioid-induced respiratory depression increases hospital costs and length of stay in patients recovering on the general care floor.

BACKGROUND: Opioid-induced respiratory depression is common on the general care floor. However, the clinical and economic burden of respiratory depression is not well-described. The PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) trial created a prediction tool to identify patients at risk of respiratory depression. The purpose of this retrospective sub-analysis was to examine healthcare utilization and hospital cost associated with respiratory depression. METHODS: One thousand three hundred thirty-five patients (N = 769 United States patients) enrolled in the PRODIGY trial received parenteral opioids and underwent continuous capnography and pulse oximetry monitoring. Cost data was retrospectively collected for 420 United States patients. Differences in healthcare utilization and costs between patients with and without ≥1 respiratory depression episode were determined. The impact of respiratory depression on hospital cost per patient was evaluated using a propensity weighted generalized linear model. RESULTS: Patients with ≥1 respiratory depression episode had a longer length of stay (6.4 ± 7.8 days vs 5.0 ± 4.3 days, p = 0.009) and higher hospital cost ($21,892 ± $11,540 vs $18,206 ± $10,864, p = 0.002) compared to patients without respiratory depression. Patients at high risk for respiratory depression, determined using the PRODIGY risk prediction tool, who had ≥1 respiratory depression episode had higher hospital costs compared to high risk patients without respiratory depression ($21,948 ± $9128 vs $18,474 ± $9767, p = 0.0495). Propensity weighted analysis identified 17% higher costs for patients with ≥1 respiratory depression episode (p = 0.007). Length of stay significantly increased total cost, with cost increasing exponentially for patients with ≥1 respiratory depression episode as length of stay increased. CONCLUSIONS: Respiratory depression on the general care floor is associated with a significantly longer length of stay and increased hospital costs. Early identification of patients at risk for respiratory depression, along with early proactive intervention, may reduce the incidence of respiratory depression and its associated clinical and economic burden. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02811302 .

New-Onset Atrial Fibrillation After Cardiac Surgery is a Significant Risk Factor for Long-Term Stroke: An Eight-Year Prospective Cohort Study.

OBJECTIVES: This study sought to determine the incidence and significance of new-onset atrial fibrillation as a risk factor for long-term stroke and mortality after cardiac surgery. DESIGN: A prospective cohort study. SETTING: Two large tertiary public hospitals. PARTICIPANTS: The study comprised 3008 patients who underwent coronary artery bypass grafting and/or valve surgery from 2008 to 2012. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: New-onset atrial fibrillation was analyzed as a risk factor for postoperative stroke using a multivariate logistic regression model after adjustment for potential confounders. A Cox regression model with time-dependent variables was used to analyze relationships between new-onset atrial fibrillation and postoperative survival. New-onset atrial fibrillation was detected in 573 (19.0%) patients. Stroke occurred in 234 (7.8%) patients during the mean postoperative follow-up period of six ± two years. The incidence of postoperative stroke in patients with new-onset atrial fibrillation (9.9%) and patients with both preoperative and postoperative atrial fibrillation (13.8%) was higher than in patients with no atrial fibrillation (6.8%) (p = 0.002). New-onset atrial fibrillation (odds ratio, 1.53; 95% confidence interval [CI], 1.08-2.18; p = 0.017) was identified as an independent risk factor for postoperative stroke. A total of 518 (17.2%) mortalities occurred within the mean postoperative follow-up period of eight ± two years. New-onset atrial fibrillation was associated with shorter survival (hazard ratio, 1.49; 95% CI, 1.22-1.81; p < 0.001) compared with patients with no atrial fibrillation. CONCLUSIONS: New-onset atrial fibrillation is a significant risk factor for long-term stroke and mortality after cardiac surgery. Close monitoring and treatment of this condition may be necessary to reduce the risk of postoperative stroke and mortality.

Prediction of Opioid-Induced Respiratory Depression on Inpatient Wards Using Continuous Capnography and Oximetry: An International Prospective, Observational Trial.

BACKGROUND: Opioid-related adverse events are a serious problem in hospitalized patients. Little is known about patients who are likely to experience opioid-induced respiratory depression events on the general care floor and may benefit from improved monitoring and early intervention. The trial objective was to derive and validate a risk prediction tool for respiratory depression in patients receiving opioids, as detected by continuous pulse oximetry and capnography monitoring. METHODS: PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) was a prospective, observational trial of blinded continuous capnography and oximetry conducted at 16 sites in the United States, Europe, and Asia. Vital signs were intermittently monitored per standard of care. A total of 1335 patients receiving parenteral opioids and continuously monitored on the general care floor were included in the analysis. A respiratory depression episode was defined as respiratory rate ≤5 breaths/min (bpm), oxygen saturation ≤85%, or end-tidal carbon dioxide ≤15 or ≥60 mm Hg for ≥3 minutes; apnea episode lasting >30 seconds; or any respiratory opioid-related adverse event. A risk prediction tool was derived using a multivariable logistic regression model of 46 a priori defined risk factors with stepwise selection and was internally validated by bootstrapping. RESULTS: One or more respiratory depression episodes were detected in 614 (46%) of 1335 general care floor patients (43% male; mean age, 58 ± 14 years) continuously monitored for a median of 24 hours (interquartile range [IQR], 17-26). A multivariable respiratory depression prediction model with area under the curve of 0.740 was developed using 5 independent variables: age ≥60 (in decades), sex, opioid naivety, sleep disorders, and chronic heart failure. The PRODIGY risk prediction tool showed significant separation between patients with and without respiratory depression (P < .001) and an odds ratio of 6.07 (95% confidence interval [CI], 4.44-8.30; P < .001) between the high- and low-risk groups. Compared to patients without respiratory depression episodes, mean hospital length of stay was 3 days longer in patients with ≥1 respiratory depression episode (10.5 ± 10.8 vs 7.7 ± 7.8 days; P < .0001) identified using continuous oximetry and capnography monitoring. CONCLUSIONS: A PRODIGY risk prediction model, derived from continuous oximetry and capnography, accurately predicts respiratory depression episodes in patients receiving opioids on the general care floor. Implementation of the PRODIGY score to determine the need for continuous monitoring may be a first step to reduce the incidence and consequences of respiratory compromise in patients receiving opioids on the general care floor.

Ideal Sequence of Didactic Lectures and Simulation in Teaching Transesophageal Echocardiography Among Anesthesiologists.

OBJECTIVE: Performing a basic perioperative transesophageal echocardiography (TEE) requires 3-dimensional knowledge of cardiac anatomy, psychomotor skills, and image interpretation. Commonly, lectures followed by simulation sequence is used for teaching TEE. Differences may occur among learners when this sequencing of instructional components is altered. The authors investigated the ideal sequence of lectures and simulation in teaching basic perioperative TEE. DESIGN: Prospective randomized comparative study. SETTING: Simulation room in a large academy tertiary care center. PARTICIPANTS: Noncardiac anesthesiologists in Singapore with no prior knowledge of TEE. INTERVENTION: Comparison of acquisition and retention of knowledge and skills between the lecture followed by simulation group (LS) and the simulation followed by lecture (SL) group. MEASUREMENTS AND MAIN RESULTS: Knowledge was assessed using multiple-choice questions (MCQs) and skills using a skill test. The primary outcome measured was the MCQ scores (post-course and retest) and the skill test scores (post-course and retest). Of the 43 anesthesiologists who were recruited, 22 were randomized into the LS group and 21 to the SL group. All participants took pre-course and post-course MCQs and post-course skill tests. Post-tests were repeated 1 month after the course to assess retention. There was no significant difference in the post-course MCQ (85.87% v 81.82%) and skill test scores (85.78% v 81.55%) between the SL and LS groups, respectively. The SL group demonstrated significantly better retention of knowledge at 1 month (MCQ score 83.5% v 72.73%; p = 0.003) and skills (skill test score 85.32% v 1.90%; p = 0.016) than the other. CONCLUSION: This study showed that, for retention (at 1 month) of both knowledge and skills, it is preferable to teach practical skills followed by theoretical knowledge to anesthesiologists who are complete novices to TEE.

Factors predicting one-year post-surgical mortality amongst older Asian patients undergoing moderate to major non-cardiac surgery - a retrospective cohort study.

BACKGROUND: While short-term perioperative outcomes have been well studied in Western surgical populations, the aim of this study is to look at the one-year perioperative mortality and its associated factors in an Asian surgical population after non-cardiac surgery. METHODS: A retrospective cohort study of 2163 patients aged above 45 undergoing non-cardiac surgery in a university-affiliated tertiary hospital from January to July 2015 was performed. Relevant demographic, clinical and surgical data were analysed to elicit their relationship to mortality at one year after surgery. A univariate analysis was first performed to identify significant variables with p-values ≤ 0.2, which were then analysed using Firth multiple logistic regression to calculate the adjusted odds ratio. RESULTS: The one-year mortality in our surgical population was 5.9%. The significant factors that increased one-year mortality include smoking (adjusted OR 2.17 (1.02-4.45), p = 0.044), anaemia (adjusted OR 1.32 (1.16-1.47), p < 0.001, for every 1 g/dL drop in haemoglobin level), lower BMI (adjusted OR 0.93 (0.87-0.98), p = 0.005, for every 1 point increase in BMI), Malay and Indian ethnicity (adjusted OR 2.68 (1.53-4.65), p = 0.001), peripheral vascular disease (adjusted OR 4.21 (1.62-10.38), p = 0.004), advanced age (adjusted OR 1.04 (1.01-1.06), p = 0.004, for every one year increase in age), emergency surgery (adjusted OR 2.26 (1.29-3.15), p = 0.005) and malignancy (adjusted OR 3.20 (1.85-5.52), p < 0.001). CONCLUSIONS: Our study shows that modifiable risk factors such as malnutrition, anaemia and smoking which affect short term mortality extend beyond the immediate perioperative period into longer term outcomes. Identification and optimization of this subset of patients are therefore vital. Further similar large studies should be done to develop a risk scoring system for post-operative long-term outcomes. This would aid clinicians in risk stratification, counselling and surgical planning, which will help in patients' decision making and care planning.

Prediction of failed facemask ventilation: new scoring system for difficult airway.

BACKGROUND: We previously have shown that there was a strong correlation between failed facemask ventilation, failed ventilation through a supraglottic airway, and difficult tracheal intubation. The primary aim of this study was to evaluate whether or not an established method to predict difficult ventilation through a supraglottic airway was also useful for predicting failed facemask ventilation. METHODS: This was a single-center, retrospective observational study. We studied 28,081 anesthetized patients in whom ventilation through a facemask, and supraglottic airway was attempted as the initial technique during induction of anesthesia, between May 2011 and March 2016. For each patient, the score which had been validated to be useful for predicting difficult ventilation through a supraglottic airway was calculated. The score ranged between 0 and 7 points, and we defined a low risk when the score was 0-3, and a high risk when the score was 4-7. To measure and compare the predictive accuracy of the score, we generated a receiver operating characteristic curve and compared the area under the curve (AUC). RESULTS: The incidence of failed facemask ventilation was significantly higher in patients with high-risk predictive score than in patients with low-risk predictive score [0.38% vs 0.056%, odds ratio 6.8 (95% CI 2.6-18.1, p value = 0.002)], and the sensitivity of the score was 25%, while the specificity was 95%, with a negative predictive value of 99%. The AUC of the score was 0.71 (95% CI 0.58-0.83). CONCLUSIONS: The predictive score for difficult ventilation through a supraglottic airway is also useful to predict failed facemask ventilation.

Comprehensive and Integrative Experimentation Setup for Large Animal Hybrid Valvular Heart Surgery.

BACKGROUND: Experimental surgical procedures for atrioventricular valves present promising translational capabilities, and preclinical studies are necessary to assess their applicability and to train young enthusiastic heart teams. Here, we present a synopsis of experimental surgical procedures on porcine models for mitral valvular (MV) and tricuspid valvular (TV) interventions; mitral valve-in-valve implantation (MViV), transapical cardioscopic (TAC) MV replacement (MVR), TAC-MV annuloplasty, and tricuspid valve-in-a-ring (TViR) procedures. METHODS: Twenty-five (n = 25) female Yorkshire pigs of 55-65 kg is the total number used in the four approaches; seven animals underwent MViV, six TAC-MVR, six TAC-MV annuloplasty, and six TViR, respectively. All were subjected to a first conventional valvular surgery (bioprosthetic valve replacement and/or prosthetic ring repair). Then, after 4 wk, a less-invasive second surgery was performed using the transcatheter approaches under investigation. Except for the TAC-MVR and annuloplasty procedures, all animals were followed up for additional 4 wk. RESULTS: (1) MViV (n = 7): Standard MVR was successfully performed in all animals. Transvalvular pressure gradients and flow velocities were (Pmax 3.77 ± 0.8 mmHg; Pmean 2.1 ± 0.6 mmHg, Vmax 97 ± 13 cm/s; Vmean 68 ± 21 cm/s). Effective MViV followed (Pmax 16.7 ± 1.8 mmHg; Pmean 6.2 ± 1.2 mmHg, Vmax 216 ± 32 cm/s; Vmean 110 ± 24 cm/s). (2) TAC-MVR (n = 6): The overall bypass time was 177.2 ± 44.2 min. Transprosthetic Pmean was 4.6 ± 2.4 mmHg; no paravalvular leaks in all animals. (3) TAC-MV annuloplasty (n = 6): The implantation time was 47 ± 6 min. MV was competent, left ventricular ejection fraction (LV-EF%) was 63 ± 4%. (4) TViR (n = 6): Conventional TV ring repair was performed in all animals (Pmax 2.42 ± 0.7 mmHg; Pmean 1.3 ± 0.6 mmHg, Vmax 82 ± 10.4 cm/s; Vmean 65.4 ± 21 cm/s). All TViRs were implanted efficiently (Pmax 4.7 ± 1.6 mmHg; Pmean 2.7 ± 0.8 mmHg, Vmax 105 ± 31 cm/s; Vmean 81 ± 16 cm/s). A mild paravalvular leak was observed in one animal (16%). CONCLUSIONS: All studied experimental valvular interventions are feasible, within the context of well-trained cardiac surgery specialists, and all possibilities should be considered when treating a patient to determine which one suits best his individual challenges and scope.

Association Between Ethnicity and Postoperative Hyperglycemia in a Southeast Asian Population Undergoing Cardiac Surgery.

OBJECTIVE: Postoperative hyperglycemia is a known risk factor for adverse outcomes following cardiac surgery. Therefore, the authors investigated the association between ethnicity and postoperative hyperglycemia in a Southeast Asian multiethnic population undergoing cardiac surgery. DESIGN: Perioperative data were analyzed prospectively. SETTING: Perioperative data were obtained from 2008 to 2010 at the 2 main heart centers in Singapore. PARTICIPANTS: Data from 911 adult patients were collected. INTERVENTIONS: All patients underwent elective cardiac surgery. MEASUREMENTS AND MAIN RESULTS: Perioperative variables, genetic associations, and outcomes of hyperglycemic versus normoglycemic patients were compared. Of the 911 patients analyzed, 47.7% (n = 435) were diabetic and 77.7% (n = 708) had postoperative hyperglycemia. Patients with postoperative hyperglycemia after cardiac surgery were more likely to have diabetes; be female, older, and more obese; and have hypertension and renal impairment. Patients of Indian ethnicity had a significantly higher incidence of postoperative hyperglycemia (86.7%, p = 0.043), as compared to Malays (79.1%) and Chinese (75.9%). Ethnicity was identified as an independent risk factor for postoperative hyperglycemia, with Indians having a significantly higher risk than Chinese (OR 2.115, p = 0.015). Although Indian ethnicity was associated with the presence of angiotensin-converting enzyme D allele (65.7%, p = 0.044), no genetic associations with postoperative hyperglycemia were identified. Postoperative hyperglycemia also was associated significantly with poorer outcomes of longer high-dependency unit stay and new-onset cardiac arrhythmias. CONCLUSION: The authors' findings demonstrated Indian ethnicity as an independent risk factor of postoperative hyperglycemia, likely due to insulin resistance and exaggerated hyperglycemic stress response, emphasizing the need for ethnic-based data unique to each population group.

History and Current Status of Cardiac Anesthesia in Singapore.

Singapore is a small Southeast Asian island city-state located at the tip of the Malay peninsula with a population of 5.61 million people. It was a former British colony that went on to become a part of Malaysia before gaining independence in 1965. Since then, Singapore has developed tremendously from a small fishing village into the region's medical hub. This article will explore the roots of cardiac anesthesia in Singapore and how it has developed into a subspecialty today.