Preoperative anemia in older individuals undergoing major abdominal surgery is associated with early postoperative morbidity: a prospective observational study.

PURPOSE: Preoperative anemia is associated with poor postoperative outcomes. Older patients have limited physiologic reserves, which renders them vulnerable to the stress of major abdominal surgery. We aimed to determine if the severity of preoperative anemia is associated with early postoperative morbidity among older patients undergoing major abdominal surgery. METHODS: Ethics approval was obtained from SingHealth Centralized Institutional Review Board. This is a prospective observational study conducted in the preoperative anesthesia clinic of a tertiary Singapore hospital from 2017 to 2021. Patient demographic data, comorbidities, and intraoperative details were collected. Outcome measures included blood transfusions, complications according to the Postoperative Morbidity Survey, days alive and out of hospital (DaOH), length of hospital stay, and mortality. RESULTS: A total of 469 patients were analyzed, 37.5% of whom had preoperative anemia (serum hemoglobin of < 13 g·dL-1 in males and < 12 g·dL-1 in females). Anemia was significantly associated with older age, a higher age-adjusted Comprehensive Complication Index score, a higher incidence of diabetes mellitus, and a higher proportion of patients with an American Society of Anesthesiologists Physical Status of III or IV. The severity of anemia was associated with the presence of early postoperative morbidity at day 5, increased blood transfusions, longer length of hospital stay, and fewer DaOH at 30 days and six months. CONCLUSION: Anemia is significantly associated with poorer postoperative outcomes in the older population. The impact of anemia on postoperative outcomes could be further evaluated with quality of life indicators, patient-reported outcome measures, and health economic tools.

RéSUMé: OBJECTIF: L'anémie préopératoire est associée à de mauvais devenirs postopératoires. Les patient·es plus âgé·es ont des réserves physiologiques limitées, ce qui les rend vulnérables au stress d'une chirurgie abdominale majeure. Nous avons cherché à déterminer si la gravité de l'anémie préopératoire était associée à une morbidité postopératoire précoce chez les personnes âgées bénéficiant d'une chirurgie abdominale majeure. MéTHODE: L'approbation éthique a été obtenue auprès du Comité d'examen institutionnel centralisé SingHealth. Il s'agit d'une étude observationnelle prospective menée dans la clinique d'anesthésie préopératoire d'un hôpital tertiaire de Singapour de 2017 à 2021. Les données démographiques des patient·es, les comorbidités et les détails peropératoires ont été recueillis. Les critères d'évaluation comprenaient les transfusions sanguines, les complications selon l'Enquête sur la morbidité postopératoire, le nombre de jours de vie hors de l'hôpital, la durée de séjour à l'hôpital et la mortalité. RéSULTATS: Au total, 469 patient·es ont été analysé·es, dont 37,5% présentaient une anémie préopératoire (hémoglobine sérique < 13 g·dL-1 chez les hommes et < 12 g·dL-1 chez les femmes). L'anémie était significativement associée à un âge plus avancé, à un score plus élevé à l'Indice de complication globale ajusté en fonction de l'âge, à une incidence plus élevée de diabète sucré et à une proportion plus élevée de patient·es de statut physique III ou IV selon l'American Society of Anesthesiologists. La sévérité de l'anémie était associée à la présence d'une morbidité postopératoire précoce au jour 5, à une augmentation des transfusions sanguines, à une durée d'hospitalisation plus longue et à une diminution des jours en vie hors hôpital à 30 jours et six mois. CONCLUSION: L'anémie est significativement associée aux moins bons devenirs postopératoires chez les personnes âgées. L'impact de l'anémie sur les devenirs postopératoires pourrait être évalué plus en détail à l'aide d'indicateurs de qualité de vie, de mesures des issues rapportées par les patient·es et d'outils d'économie de la santé.

Transforming the perioperative medicine care model: The Singapore experience.

More than 300 million surgeries are performed worldwide annually. Established perioperative centres in the UK, USA and Australia have demonstrated the impact of improving perioperative care in reducing costs, increasing patient satisfaction and improving population health. Likewise, the surgical burden of care in Asia is increasing, but with sociocultural, economic and epigenetic differences compared to the west. As Singapore's largest hospital, the Singapore General Hospital pre-admission perioperative clinic sees about 20,000 patients annually. We aim to illustrate Singapore General Hospital's perioperative model of care to contribute to the paucity of literature describing perioperative programme implementation within Asia, and to encourage the cross-sharing of perioperative practices internationally. Our perioperative framework navigates risk assessment, risk counselling, and mitigation of health, medical and functional risks to better patients' perioperative outcomes and population health. We have implemented evidence-based pathways for common conditions such as anaemia and malnutrition, including a multidisciplinary programme for the elderly to tackle frailty and reduce length of stay. We describe how we have enhanced local risk profiling with the Combined Assessment of Risk Encountered in Surgery surgical risk calculator derived locally using a gradient boosting machine learning model. Finally, we report clinical outcomes of these interventions and discuss further challenges and new initiatives at each tier of our perioperative model. Our perioperative care model provides a framework that other centres can adopt to promote value-driven care, while catering for differences in the Asian population, thereby promoting evidence-based improvements in the area of perioperative medicine.

Real-world results of the implementation of preoperative anaemia clinic with intravenous iron therapy for treating iron-deficiency anaemia: a propensity-matched case-control study.

BACKGROUND: Preoperative anaemia is associated with blood transfusion and longer hospital length of stay. Preoperative iron deficiency anaemia (IDA) can be treated with oral or intravenous (IV) iron. IV iron can raise haemoglobin faster compared with oral iron. However, its ability to reduce blood transfusion and length of stay in clinical trials is inconclusive. This study aims to compare blood transfusion and hospital length of stay between anemic patients who received preoperative IV iron versus standard care, after implementation of a protocol in 2017 to screen patients for preoperative IDA, and its treatment with IV iron. METHODS: Retrospective before-after cohort study comparing 89 patients who received IV iron preoperatively in 2017, with historic patients who received oral iron therapy (selected by propensity score matching (PSM) from historic cohort of 7,542 patients who underwent surgery in 2016). Propensity score was calculated using ASA status, age, gender, surgical discipline, surgical risk and preoperative haemoglobin concentration. Both 1:1 and 1:2 matching were performed as sensitivity analysis. RESULTS: After PSM, there was no statistically significant difference in distribution of preoperative clinical variables. There was no significant difference in proportion of cases requiring transfusion nor a difference in average units transfused per patient. IV iron cohort stayed in hospital on average 8.0 days compared to non-IV iron cohort 14.1-15.1 days (P=0.006, P=0.013 respectively). Average time from IV iron therapy to surgery was 10.5 days. CONCLUSIONS: Preoperative IV iron therapy for patients with IDA undergoing elective surgery may not reduce perioperative blood transfusion, but this could be due to the short time between therapy and surgery. Implementation of IV iron therapy may reduce hospital length of stay compared to standard care for anemic patients, although this may be enhanced by concomitant improvement in perioperative care.

A Newly Proposed HbA1C-Hemoglobin Ratio - A Better Predictor of Outcomes in Cardiac Surgery When Compared to HbA1C and Anemia Alone.

HbA1C's predictive value for postoperative complications in cardiac surgery has been mixed. Studies did not account for HbA1C being over-read in anemic patients. This study proposes a novel way of using a ratio of HbA1C over hemoglobin (HH ratio). Retrospective recruitment of patients undergoing cardiac surgery was done with ethics approval. The primary objective of our study is to look for the correlation of HH ratio with 90-day (short-term) and 1-year (long-term) mortality. The secondary objective is to investigate its association with other adverse events. Statistical analysis was done using multivariable regressions and Cox proportional hazard models. Of the 974 patients recruited, 618 had a HH Ratio<0.5, 284 between 0.5-0.7 and 72 had the ratio >0.7. HH ratio of 0.5-0.7 and >0.7 was associated with 90-day mortality (HR 5.12, P = 0.033 and HR 7.25, P= 0.048 respectively) and 1-year mortality (HR 4.53, P = 0.028 and HR 9.20, P = 0.022 respectively). The higher HH ratio groups were also associated with increased length of stay (hours) in the intensive care unit (P < 0.001) and renal complications (P < 0.001). Our study showed a positive association of HH ratio with 90-day and 1-year mortality and postoperative adverse outcomes in patients undergoing cardiac surgery. The HH ratio has the potential to be a new perioperative target.

Utilizing Machine Learning Methods for Preoperative Prediction of Postsurgical Mortality and Intensive Care Unit Admission.

OBJECTIVE: To compare the performance of machine learning models against the traditionally derived Combined Assessment of Risk Encountered in Surgery (CARES) model and the American Society of Anaesthesiologists-Physical Status (ASA-PS) in the prediction of 30-day postsurgical mortality and need for intensive care unit (ICU) stay >24 hours. BACKGROUND: Prediction of surgical risk preoperatively is important for clinical shared decision-making and planning of health resources such as ICU beds. The current growth of electronic medical records coupled with machine learning presents an opportunity to improve the performance of established risk models. METHODS: All patients aged 18 years and above who underwent noncardiac and nonneurological surgery at Singapore General Hospital (SGH) between 1 January 2012 and 31 October 2016 were included. Patient demographics, comorbidities, preoperative laboratory results, and surgery details were obtained from their electronic medical records. Seventy percent of the observations were randomly selected for training, leaving 30% for testing. Baseline models were CARES and ASA-PS. Candidate models were trained using random forest, adaptive boosting, gradient boosting, and support vector machine. Models were evaluated on area under the receiver operating characteristic curve (AUROC) and area under the precision-recall curve (AUPRC). RESULTS: A total of 90,785 patients were included, of whom 539 (0.6%) died within 30 days and 1264 (1.4%) required ICU admission >24 hours postoperatively. Baseline models achieved high AUROCs despite poor sensitivities by predicting all negative in a predominantly negative dataset. Gradient boosting was the best performing model with AUPRCs of 0.23 and 0.38 for mortality and ICU admission outcomes respectively. CONCLUSIONS: Machine learning can be used to improve surgical risk prediction compared to traditional risk calculators. AUPRC should be used to evaluate model predictive performance instead of AUROC when the dataset is imbalanced.

Society for Perioperative Assessment and Quality Improvement (SPAQI) Consensus Statement on Perioperative Smoking Cessation.

Smokers are at increased risk for surgical complications. Despite the known benefits of smoking cessation, many perioperative health care providers do not routinely provide smoking cessation interventions. The variation in delivery of perioperative smoking cessation interventions may be due to limited high-level evidence for whether smoking cessation interventions used in the general population are effective and feasible in the surgical population, as well as the challenges and barriers to implementation of interventions. Yet smoking is a potentially modifiable risk factor for improving short- and long-term patient outcomes. The purpose of the Society for Perioperative Assessment and Quality Improvement (SPAQI) Consensus Statement on Perioperative Smoking Cessation is to present recommendations based on current scientific evidence in surgical patients. These statements address questions regarding the timing and intensity of interventions, roles of perioperative health care providers, and behavioral and pharmacological interventions. Barriers and strategies to overcome challenges surrounding implementation of interventions and future areas of research are identified. These statements are based on the current state of knowledge and its interpretation by a multidisciplinary group of experts at the time of publication.

STOP-Bang Questionnaire: A Practical Approach to Screen for Obstructive Sleep Apnea.

There exists a high prevalence of OSA in the general population, a great proportion of which remains undiagnosed. The snoring, tiredness, observed apnea, high BP, BMI, age, neck circumference, and male gender (STOP-Bang) questionnaire was specifically developed to meet the need for a reliable, concise, and easy-to-use screening tool. It consists of eight dichotomous (yes/no) items related to the clinical features of sleep apnea. The total score ranges from 0 to 8. Patients can be classified for OSA risk based on their respective scores. The sensitivity of STOP-Bang score ≥ 3 to detect moderate to severe OSA (apnea-hypopnea index [AHI] > 15) and severe OSA (AHI > 30) is 93% and 100%, respectively. Corresponding negative predictive values are 90% and 100%. As the STOP-Bang score increases from 0 to 2 up to 7 to 8, the probability of moderate to severe OSA increases from 18% to 60%, and the probability of severe OSA rises from 4% to 38%. Patients with a STOP-Bang score of 0 to 2 can be classified as low risk for moderate to severe OSA whereas those with a score of 5 to 8 can be classified as high risk for moderate to severe OSA. In patients whose STOP-Bang scores are in the midrange (3 or 4), further criteria are required for classification. For example, a STOP-Bang score of ≥ 2 plus a BMI > 35 kg/m(2) would classify that patient as having a high risk for moderate to severe OSA. In this way, patients can be stratified for OSA risk according to their STOP-Bang scores.

Perioperative management for the obese outpatient.

PURPOSE OF REVIEW: Incidence of obesity continues to rise and ambulatory surgical centers will need to be prepared for the increase in the obese surgical patients. This review aims to provide recent updates in managing the obese patients in an ambulatory surgical center and to address key clinical questions, such as patient selection, assessment and optimization, as well as important perioperative consideration. RECENT FINDINGS: With low rate of major intraoperative adverse events, obesity has not been associated with unplanned admission after day surgical procedures. There is, however, a higher rate of perioperative adverse events in the super-obese patients. Recent developments in patient assessment include validation of STOP-Bang questionnaire for obstructive sleep apnea in the obese population. Nevertheless, patients with obesity hypoventilation syndrome should be identified and optimized as they are more prone to develop adverse events. The obese patients are also at a higher risk of difficult airway, and recommendations for the airway management are available. SUMMARY: With extra considerations and meticulous perioperative management, it is well tolerated to accept obese patients for ambulatory surgery. The super-obese patients, however, are at a higher risk for perioperative adverse events.