Preoperative factors predict prolonged length of stay, serious adverse complications, and readmission following operative intervention of proximal humerus fractures: a machine learning analysis of a national database

Background

Proximal humerus fractures are a common injury, predominantly affecting older adults. This study aimed to develop risk-prediction models for prolonged length of hospital stay (LOS), serious adverse complications, and readmission within 30 days of surgically treated proximal humerus fractures using machine learning (ML) techniques.

Methods

Adult patients (age >18) who underwent open reduction internal fixation (ORIF), hemiarthroplasty, or total shoulder arthroplasty for proximal humerus fracture between 2016 and 2021 were included. Preoperative demographic and clinical variables were collected for all patients and used to establish ML-based algorithms. The model with optimal performance was selected according to area under the curve (AUC) on the receiver operating curve (ROC) curve and overall accuracy, and the specific predictive features most important to model derivation were identified.

Results

A total of 7473 patients were included (72.1% male, mean age 66.2 ± 13.7 years). Models produced via gradient boosting performed best for predicting prolonged LOS and complications. The model predicting prolonged LOS demonstrated good discrimination and performance, as indicated by (Mean: 0.700, SE: 0.017), recall (Mean: 0.551, SE: 0.017), accuracy (Mean: 0.717, SE: 0.010), F1-score (Mean: 0.616, SE: 0.014), AUC (Mean: 0.779, SE: 0.010), and Brier score (Mean: 0.283, SE: 0.010) Preoperative hematocrit, preoperative platelet count, and patient age were considered the strongest predictive features. The model predicting serious adverse complications exhibited comparable discrimination [precision (Mean: 0.226, SE: 0.024), recall (Mean: 0.697, SE: 0.048), accuracy (Mean: 0.811, SE: 0.010), F1-score (Mean: 0.341, SE: 0.031)] and superior performance relative to the LOS model [AUC (Mean: 0.806, SE: 0.024), Brier score (Mean: 0.189, SE: 0.010), noting preoperative hematocrit, operative time, and patient age to be most influential. However, the 30-day readmission model achieved the weakest relative performance, displaying low measures of precision (Mean: 0.070, SE: 0.012) and recall (Mean: 0.389, SE: 0.053), despite good accuracy (Mean: 0.791, SE: 0.009).

Conclusion

Predictive models constructed using ML techniques demonstrated favorable discrimination and satisfactory-to-excellent performance in forecasting prolonged LOS and serious adverse complications occurring within 30 days of surgical intervention for proximal humerus fracture. Modifiable preoperative factors such as hematocrit and platelet count were identified as significant predictive features, suggesting that clinicians could address these factors during preoperative patient optimization to enhance outcomes. Overall, these findings highlight the potential for ML techniques to enhance preoperative management, facilitate shared decision-making, and enable more effective and personalized orthopedic care by exploring alternative approaches to risk stratification.

Patient Blood Management as an Emerging Concept in Quality: The Role of Nurses

BACKGROUND

Transfusion of blood components has long been considered lifesaving therapy. While blood transfusion may be clinically indicated as a treatment option for some patients, the benefits of transfusion in asymptomatic, hemodynamically stable patients are questionable.

PROBLEM

Blood component transfusion is routinely used as a default therapy when not clinically indicated, increasing the risk of poor patient outcomes, adverse events, pressures on blood supply and availability, and increased health care costs.

APPROACH

Nurses have the responsibility to advocate for patients and reduce/avoid unnecessary blood transfusion through the implementation of patient blood management (PBM). The PBM paradigm includes treatment of anemia, minimizing blood loss and bleeding, optimization of coagulation, and employing true patient-centered decision making.

CONCLUSIONS

PBM should become the standard of care with the goal of improving health care quality and patient outcomes while using the multidisciplinary team for its implementation. As advocates for their patients, nurses can play a major role in the development, implementation, and promotion of PBM.

Preoperative Anemia and Postoperative Outcomes in Cardiac Surgery: A Mediation Analysis Evaluating Intraoperative Transfusion Exposures

BACKGROUND

Preoperative anemia is associated with adverse outcomes in cardiac surgery, yet it remains unclear what proportion of this association is mediated through red blood cell (RBC) transfusions.

METHODS

This is a historical observational cohort study of adults undergoing coronary artery bypass grafting or valve surgery on cardiopulmonary bypass at an academic medical center between May 1, 2008, and May 1, 2018. A mediation analysis framework was used to evaluate the associations between preoperative anemia and postoperative outcomes, including a primary outcome of acute kidney injury (AKI). Intraoperative RBC transfusions were evaluated as mediators of preoperative anemia and outcome relationships. The estimated total effect, average direct effect of preoperative anemia, and percent of the total effect mediated through transfusions are presented with 95% confidence intervals and P -values.

RESULTS

A total of 4117 patients were included, including 1234 (30%) with preoperative anemia. Overall, 437 of 4117 (11%) patients went on to develop AKI, with a greater proportion of patients having preoperative anemia (219 of 1234 [18%] vs 218 of 2883 [8%]). In multivariable analyses, the presence of preoperative anemia was associated with increased postoperative AKI (6.4% [4.2%-8.7%] absolute difference in percent with AKI, P < .001), with incremental decreases in preoperative hemoglobin concentrations displaying greater AKI risk (eg, 11.9% [6.9%-17.5%] absolute increase in probability of AKI for preoperative hemoglobin of 9 g/dL compared to a reference of 14 g/dL, P < .001). The association between preoperative anemia and postoperative AKI was primarily due to direct effects of preoperative anemia (5.9% [3.6%-8.3%] absolute difference, P < .001) rather than mediated through intraoperative RBC transfusions (7.5% [-4.3% to 21.1%] of the total effect mediated by transfusions, P = .220). Preoperative anemia was also associated with longer hospital durations (1.07 [1.05-1.10] ratio of geometric mean length of stay, P < .001). Of this total effect, 38% (22%, 62%; P < .001) was estimated to be mediated through subsequent intraoperative RBC transfusion. Preoperative anemia was not associated with reoperation or vascular complications.

CONCLUSIONS

Preoperative anemia was associated with higher odds of AKI and longer hospitalizations in cardiac surgery. The attributable effects of anemia and transfusion on postoperative complications are likely to differ across outcomes. Future studies are necessary to further evaluate mechanisms of anemia-associated postoperative organ injury and treatment strategies.

Standard of Care Versus Octreotide in Angiodysplasia-Related Bleeding (the OCEAN Study): A Multicenter Randomized Controlled Trial

BACKGROUND & AIMS

Gastrointestinal angiodysplasias are vascular anomalies that may result in transfusion-dependent anemia despite endoscopic therapy. An individual patient data meta-analysis of cohort studies suggests that octreotide decreases rebleeding rates, but component studies possessed a high risk of bias. We investigated the efficacy of octreotide in reducing the transfusion requirements of patients with angiodysplasia-related anemia in a clinical trial setting.

METHODS

The study was designed as a multicenter, open-label, randomized controlled trial. Patients with angiodysplasia bleeding were required to have had at least 4 red blood cell (RBC) units or parental iron infusions, or both, in the year preceding randomization. Patients were allocated (1:1) to 40-mg octreotide long-acting release intramuscular every 28 days or standard of care, including endoscopic therapy. The treatment duration was 1 year. The primary outcome was the mean difference in the number of transfusion units (RBC + parental iron) between the octreotide and standard of care groups. Patients who received at least 1 octreotide injection or followed standard of care for at least 1 month were included in the intention-to-treat analyses. Analyses of covariance were used to adjust for baseline transfusion requirements and incomplete follow-up.

RESULTS

We enrolled 62 patients (mean age, 72 years; 32 men) from 17 Dutch hospitals in the octreotide (n = 31) and standard of care (n = 31) groups. Patients required a mean number of 20.3 (standard deviation, 15.6) transfusion units and 2.4 (standard deviation, 2.0) endoscopic procedures in the year before enrollment. The total number of transfusions was lower with octreotide (11.0; 95% confidence interval [CI], 5.5-16.5) compared with standard of care (21.2; 95% CI, 15.7-26.7). Octreotide reduced the mean number of transfusion units by 10.2 (95% CI, 2.4-18.1; P = .012). Octreotide reduced the annual volume of endoscopic procedures by 0.9 (95% CI, 0.3-1.5).

CONCLUSIONS

Octreotide effectively reduces transfusion requirements and the need for endoscopic therapy in patients with angiodysplasia-related anemia.

CLINICALTRIALS

gov, NCT02384122.

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.

Maximizing longevity: erythropoietin's impact on sickle cell anaemia survival rates

Sickle cell anaemia (SCA) stands as a hereditary blood disorder characterized by mutated haemoglobin, causing red blood cells to adopt a sickle shape, leading to complications like vaso-occlusive crises, anaemia, and organ damage. Despite advancements in treatment, managing SCA remains challenging, with limited options to increase life expectancy and improve quality of life for affected individuals. This paper reviews the potential impact of erythropoietin (EPO) therapy in enhancing life expectancy and ameliorating complications in individuals with SCA. EPO, primarily recognized for its role in stimulating red blood cell production, holds promise in mitigating anaemia, reducing transfusion dependence, and possibly diminishing the frequency and severity of vaso-occlusive crises in SCA patients. Moreover, by stimulating red blood cell production, EPO therapy might alleviate the vaso-occlusive process, thus reducing the frequency of painful crises and associated complications. Additionally, considering the potential side effects and the need for continuous monitoring, the use of EPO in SCA treatment requires cautious consideration. The potential of EPO therapy in SCA offers a glimpse into novel strategies aimed at improving the quality of life and extending the life expectancy of affected individuals. In conclusion, while the application of EPO in SCA treatment holds promise, additional research is indispensable to comprehend its precise role, optimize dosing strategies, and ensure safety, thereby paving the way for enhanced life expectancy and improved outcomes for individuals living with SCA.

Alternative blood transfusion triggers: a narrative review

BACKGROUND

Anemia, characterized by low hemoglobin levels, is a global public health concern. Anemia is an independent factor worsening outcomes in various patient groups. Blood transfusion has been the traditional treatment for anemia; its triggers, primarily based on hemoglobin levels; however, hemoglobin level is not always an ideal trigger for blood transfusion. Additionally, blood transfusion worsens clinical outcomes in certain patient groups. This narrative review explores alternative triggers for red blood cell transfusion and their physiological basis.

MAIN TEXT

The review delves into the physiology of oxygen transport and highlights the limitations of using hemoglobin levels alone as transfusion trigger. The main aim of blood transfusion is to optimize oxygen delivery, necessitating an individualized approach based on clinical signs of anemia and the balance between oxygen delivery and consumption, reflected by the oxygen extraction rate. The narrative review covers different alternative triggers. It presents insights into their diagnostic value and clinical applications, emphasizing the need for personalized transfusion strategies.

CONCLUSION

Anemia and blood transfusion are significant factors affecting patient outcomes. While restrictive transfusion strategies are widely recommended, they may not account for the nuances of specific patient populations. The search for alternative transfusion triggers is essential to tailor transfusion therapy effectively, especially in patients with comorbidities or unique clinical profiles. Investigating alternative triggers not only enhances patient care by identifying more precise indicators but also minimizes transfusion-related risks, optimizes blood product utilization, and ensures availability when needed. Personalized transfusion strategies based on alternative triggers hold the potential to improve outcomes in various clinical scenarios, addressing anemia's complex challenges in healthcare. Further research and evidence are needed to refine these alternative triggers and guide their implementation in clinical practice.

Part II: Blood Transfusion and Donor Exposure in the Surgical Management of Trigonocephaly Patients: A Protocol From Alder Hey Craniofacial Unit

Trigonocephaly is a craniofacial malformation caused by premature fusion of the metopic suture. Surgical correction frequently results in the need for blood transfusion. Transfusion complications include transfusion-transmitted infections (TTIs), immune-mediated reactions, and volume overload. Donor exposure (DE) describes the number of blood products from unique donors with increasing DE equating to an increased risk of TTI. We evaluate data on 204 trigonocephaly patients covering 20 years of practice with respect to blood transfusions and DE. This represents the largest series from a single unit to date. A protocol based on our experiences has been devised that summarizes the key interventions we recommend to minimize blood transfusions and DE in craniofacial surgery. Patients operated on between 2000 and 2020 were included. DE and a range of values were calculated including estimated red cell loss (ERCL) and estimated red cell volume transfused (ERCVT). Groups were established by relevant interventions and compared using the Mann-Whitney U test. Mean DE fell from 1.46 at baseline to 0.85 ( P <0.05). Median allogenic transfusion volume fell from 350 mL at baseline to 250 mL ( P <0.05). Median ERCL fell from 15.05 mL/kg at baseline to 12.39 mL/kg and median ERCVT fell from 20.85 to 15.98 mL/kg. Changes in ERCL and ERCVT did not reach statistical significance. DE can be minimized with the introduction of key interventions such as a restrictive transfusion policy, preoperative iron, cell saver, tranexamic acid, and use of a matchstick burr for osteotomies.

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.

Point-of-care haemoglobin accuracy and transfusion outcomes in non-cardiac surgery at a Canadian tertiary academic hospital: protocol for the PREMISE observational study

INTRODUCTION

Transfusions in surgery can be life-saving interventions, but inappropriate transfusions may lack clinical benefit and cause harm. Transfusion decision-making in surgery is complex and frequently informed by haemoglobin (Hgb) measurement in the operating room. Point-of-care testing for haemoglobin (POCT-Hgb) is increasingly relied on given its simplicity and rapid provision of results. POCT-Hgb devices lack adequate validation in the operative setting, particularly for Hgb values within the transfusion zone (60-100 g/L). This study aims to examine the accuracy of intraoperative POCT-Hgb instruments in non-cardiac surgery, and the association between POCT-Hgb measurements and transfusion decision-making.

METHODS AND ANALYSIS

PREMISE is an observational prospective method comparison study. Enrolment will occur when adult patients undergoing major non-cardiac surgery require POCT-Hgb, as determined by the treating team. Three concurrent POCT-Hgb results, considered as index tests, will be compared with a laboratory analysis of Hgb (lab-Hgb), considered the gold standard. Participants may have multiple POCT-Hgb measurements during surgery. The primary outcome is the difference in individual Hgb measurements between POCT-Hgb and lab-Hgb, primarily among measurements that are within the transfusion zone. Secondary outcomes include POCT-Hgb accuracy within the entire cohort, postoperative morbidity, mortality and transfusion rates. The sample size is 1750 POCT-Hgb measurements to obtain a minimum of 652 Hgb measurements <100 g/L, based on an estimated incidence of 38%. The sample size was calculated to fit a logistic regression model to predict instances when POCT-Hgb are inaccurate, using 4 g/L as an acceptable margin of error.

ETHICS AND DISSEMINATION

Institutional ethics approval has been obtained by the Ottawa Health Science Network-Research Ethics Board prior to initiating the study. Findings from this study will be published in peer-reviewed journals and presented at relevant scientific conferences. Social media will be leveraged to further disseminate the study results and engage with clinicians.

Outcomes following perioperative red blood cell transfusion in patients undergoing elective major abdominal surgery: a systematic review and meta-analysis

BACKGROUND

Perioperative red blood cell transfusion is a double-edged sword for surgical patients. While transfusion of red cells can increase oxygen delivery by increasing haemoglobin levels, its impact on short- and long-term postoperative outcomes, particularly in patients undergoing elective major abdominal surgery, is unclear.

METHODS

We conducted a systematic review and meta-analysis on the effect of perioperative blood transfusions on postoperative outcomes in elective major abdominal surgery. PubMed, Cochrane, and Scopus databases were searched for studies with data collected between January 1, 2000 and June 6, 2020. The primary outcome was short-term mortality, including all-cause 30-day or in-hospital mortality. Secondary outcomes included long-term all-cause mortality, any morbidity, infectious complications, overall survival, and recurrence-free survival. No randomised controlled trials were found. Thirty-nine observational studies were identified, of which 37 were included in the meta-analysis.

RESULTS

Perioperative blood transfusion was associated with short-term all-cause mortality (odds ratio [OR] 2.72, 95% confidence interval [CI] 1.89-3.91, P<0.001), long-term all-cause mortality (hazard ratio 1.35, 95% CI 1.09-1.67, P=0.007), any morbidity (OR 2.18, 95% CI 1.81-2.64, P<0.001), and infectious complications (OR 1.90, 95% CI 1.60-2.26, P<0.001). Perioperative blood transfusion remained associated with short-term mortality in the sensitivity analysis after excluding studies that did not control for preoperative anaemia (OR 2.27, 95% CI 1.59-3.24, P<0.001).

CONCLUSIONS

Perioperative blood transfusion in patients undergoing elective major abdominal surgery is associated with poorer short- and long-term postoperative outcomes. This highlights the need to implement patient blood management strategies to manage and preserve the patient's own blood and reduce the need for red blood cell transfusion.

TRIAL REGISTRATION

PROSPERO (CRD42021254360).

Preoperative moderate to severe anemia is associated with increased postoperative major adverse cardiac and cerebral events and pulmonary complications: a propensity score-matched analysis in hip fracture surgery patients over 80 years old

BACKGROUND

Anemia is a common health problem in the elderly. Preoperative anemia is a risk factor for postoperative outcomes in the elderly for hip fracture. The objective of the study was to explore the relationship between preoperative moderate to severe anemia and postoperative morbidity and mortality in hip fracture patients over 80 years old.

METHODS

We performed a retrospective cohort study exploring preoperative moderate to severe anemia and postoperative morbidity and mortality. Patients over 80 years old undergoing hip fracture surgery were included in the study. Data were collected for major adverse cardiac and cerebral events (MACCE), postoperative pulmonary complications (PPCs), in-hospital mortality, delirium, gastrointestinal complication, deep venous thrombus (DVT), acute renal failure, ICU admission, and perioperative transfusion > 2 units rate.

RESULTS

A total of 912 eligible patients were included for unmatched cohort analysis, and 512 patients were included for matched cohort analysis after propensity score matching. Baseline characteristics between the normal to mild anemia and moderate to severe anemia groups were significantly different. More patients in the moderate to severe cohort had a higher ASA classification grade III and female ratio. Patients in the moderate and severe anemia cohorts had more MACCE (unadjusted: odds ratio [OR] 1.968, 96% CI 1.090-3.555, P 0.023; adjusted: OR 1.929, 95% CI 1.014-3.668, P 0.045) and PPCs (unadjusted: OR 2.616, 95% CI 1.442-4.748, P 0.001; adjusted: OR 2.352, 95% CI 1.225-4.516, P 0.010) than patients with normal or mild anemia. However, the transfusion > 2 units rate was not significantly different between the two cohorts (unadjusted: OR 0.967, 95% CI 0.737-1.270, P 0.811; adjusted: OR 0.941, 95% CI 0.693-1.278, P 0.697). The in-hospital mortality, delirium rate, gastrointestinal complication, ICU admission, and DVT were similar. However, the in-hospital mortality was much higher (3.6%, 21/591 vs 1.6%, 5/321) in the moderate to severe anemia cohort. Furthermore, after propensity score-matched analysis, MACCE and PPCs were also significantly increased in the moderate to severe anemia cohort (OR 2.196 & 3.171, 95% CI 1.0794.470 & 1.563-6.436, P 0.027 & 0.001), which were in accordance with the unadjusted and adjusted results in the unmatched cohorts.

CONCLUSIONS

Moderate to severe preoperative anemia (< 11 g/dl) is associated with increased postoperative major adverse cardiac and cerebral events and pulmonary complications. Additionally, in-hospital mortality was not significant but was higher in the preoperative moderate to severe anemia cohort. Preoperative assessment and correction of hemoglobin level to above 11 g/dl might reduce MACCE, PPCs, and in-hospital mortality in hip fracture patients over 80 years old.

Preoperative Anemia is Associated with Poorer Postoperative Outcomes in Patients Undergoing Infrainguinal Bypass Surgery

BACKGROUND

Preoperative anemia is an important, modifiable risk factor among surgical patients. However, data are scarce on the impact of preoperative anemia on postoperative outcomes after infrainguinal bypass.

METHODS

In this multi-institutional analysis, data were retrospectively collected on all infrainguinal bypass procedures performed between 2010 and 2020. Patients were grouped by preoperative hemoglobin as per the National Cancer Institute anemia scale (mild, 10 g/dL-lower limit of normal; moderate, 8.0-9.9 g/dL; severe, 6.5-7.9 g/dL). Multivariable comparisons were performed using logistic regression analysis.

RESULTS

A total of 492 patients underwent bypass for peripheral artery disease over the 10-year study period. Median preoperative hemoglobin was 11.0 g/dL (interquartile range 9.5-12.7) and median follow-up was 1.7 years. Preoperative anemia was prevalent among bypass patients (mild 52.4% [n = 258], moderate 26.4% [n = 130], and severe 5.1% [n = 25]). Women were more likely to have moderate (49.2% [women] vs. 50.8% [men]) or severe anemia (52.0% [women] vs. 48.0% [men]) compared with normal hemoglobin (17.7% [women] vs. 82.3% [men]) (P < 0.001). Patients with preoperative anemia were more likely to present with tissue loss (22.8% [normal] vs. 47.7% [moderate] vs. 52.0% [severe], P = 0.01). Bypass target and conduit types were similar between groups. Anemic patients had longer median hospital length of stay compared with nonanemic patients (4 days [normal] vs. 5 days [mild] vs. 6 days [moderate] vs. 7 days [severe], P < 0.001). Postoperative mortality at 30 days was similar across anemia groups (2.5% [normal] vs. 4.6% [moderate] vs. 8.0% [severe], P = 0.23). On multivariable analysis, however, postoperative mortality was independently associated with severe anemia (odds ratio 7.5 [1.2-48.8], P = 0.04) and male gender (odds ratio 7.5 [1.2-26.4], P = 0.03).

CONCLUSIONS

Preoperative anemia is common among patients undergoing infrainguinal bypass surgery and is an independent risk factor for postoperative mortality. Future investigation is needed to determine whether correction of anemia improves postoperative outcomes in these high-risk patients.

A model based on electronic health records to predict transfusion events in on-pump cardiac surgery

Perioperative blood transfusion is costly and raises safety concerns. We developed and validated a model for predicting minor, moderate, or major transfusion given to patients during on-pump cardiac procedures based on two centers' database. Model performance incorporating 7 variables on the development set had an AUC of 0.803 [95% CI, 0.790-0.815] for minor transfusion; moderate transfusion, giving an AUC of 0.822 (95% CI, 0.803-0.841); and major transfusion, giving an AUC of 0.813 (95% CI, 0.759-0.866). Model performance on the validation set had an AUC of 0.739 (95% CI 0.714-0.765), 0.730 (95% CI 0.702-0.758), and 0.713 (95% CI 0.677-0.749), respectively. A model based entirely on readily available electronic health records can accurately predict intraoperative minor, moderate, or major transfusion and provide individualized transfusion risk profiles before surgery among those on-pump cardiac surgical patients, and may help guide patient management.

Predictive indicators for determining red blood cell transfusion strategies in the emergency department

BACKGROUND AND IMPORTANCE

Appropriate decision-making is critical for transfusions to prevent unnecessary adverse outcomes; however, transfusion in the emergency department (ED) can only be decided based on sparse evidence in a limited time window.

OBJECTIVES

This study aimed to identify factors associated with appropriate red blood cell (RBC) transfusion in the ED by analyzing retrospective data of patients who received transfusions at a single center.

OUTCOME MEASURES AND ANALYSIS

This study analyzed associations between transfusion appropriateness and sex, age, initial vital signs, an ED triage score [the Korean Triage and Acuity Scale (KTAS)], the length of stay, and the hemoglobin (Hb) concentration.

MAIN RESULTS

Of 10 490 transfusions, 10 109 were deemed appropriate, and 381 were considered inappropriate. A younger age ( P  < 0.001) and a KTAS level of 3-5 ( P  = 0.028) were associated with inappropriate transfusions, after adjusting for O 2 saturation and the Hb level.

CONCLUSIONS

In this single-center retrospective study, younger age and higher ED triage scores were associated with the appropriateness of RBC transfusions.

Impact of Red Blood Cell Transfusion on In-hospital Mortality of Isolated Coronary Artery Bypass Graft Surgery: A Retrospective Observational Study of French Nationwide 3-year Cohort

OBJECTIVE

To assess the relationship between red blood cell (RBC) transfusion exposure and in-hospital mortality after isolated coronary artery bypass graft (CABG) surgery.

BACKGROUND

RBC transfusion was commonly used to treat anemia in isolated CABG surgery, but transfusion was found an independent risk factor of postoperative mortality; recent guidelines on patient blood management strategy issued in the last decade may have changed transfusion incidence and related mortality.

METHODS

A retrospective cohort study was conducted from the National database on patients' hospital discharge reports. Consecutive adult patients who underwent isolated CABG surgery in France from January 1, 2016, to December 31, 2018, were included. The primary outcome was the in-hospital mortality rate. RBC transfusion during the hospital stay was identified by specific codes and ordered as categorical variables (no, moderate, or massive transfusion).

RESULTS

A total of 37,498 participants were studied [mean (SD) age, 66.5 (9.6) years, 31,587 (84.2%) were men]. In-hospital mortality rate was 1.45% (n=541) and RBC transfusion rate was 9.4% (n=3521). In-hospital deaths were more frequent among transfused patients [1.06% (361) if no transfusion up to 10.2% (n=113) if massive transfusion]. After adjustment for confounding variables, RBC transfusion remained a significant independent factor of in-hospital mortality: odds ratio=1.66 (95% confidence interval: 1.27-2.19, P <0.001) for moderate transfusion, 6.40 (95% confidence interval: 5.07-8.09, P <0.001) if massive.

CONCLUSIONS AND RELEVANCE

Despite a modest patients' exposure to transfusion, this study suggests that RBC administration is an independent factor of in-hospital mortality in isolated CABG surgery.

Benefits of Prehabilitation before Complex Aortic Surgery

The purpose of this narrative review was to detail and discuss the underlying principles and benefits of preoperative interventions addressing risk factors for perioperative adverse events in open aortic surgery (OAS). The term "complex aortic disease" encompasses juxta/pararenal aortic and thoraco-abdominal aneurysms, chronic aortic dissection and occlusive aorto-iliac pathology. Although endovascular surgery has been increasingly favored, OAS remains a durable option, but by necessity involves extensive surgical approaches and aortic cross-clamping and requires a trained multidisciplinary team. The physiological stress of OAS in a fragile and comorbid patient group mandates thoughtful preoperative risk assessment and the implementation of measures dedicated to improving outcomes. Cardiac and pulmonary complications are one of the most frequent adverse events following major OAS and their incidences are correlated to the patient's functional status and previous comorbidities. Prehabilitation should be considered in patients with risk factors for pulmonary complications including advanced age, previous chronic obstructive pulmonary disease, and congestive heart failure with the aid of pulmonary function tests. It should also be combined with other measures to improve postoperative course and be included in the more general concept of enhanced recovery after surgery (ERAS). Although the current level of evidence regarding the effectiveness of ERAS in the setting of OAS remains low, an increasing body of literature has promoted its implementation in other specialties. Consequently, vascular teams should commit to improving the current evidence through studies to make ERAS the standard of care for OAS.

Recommendations From the International Consensus Conference on Anemia Management in Surgical Patients (ICCAMS)

BACKGROUND

Perioperative anemia has been associated with increased risk of red blood cell transfusion and increased morbidity and mortality after surgery. The optimal approach to the diagnosis and management of perioperative anemia is not fully established.

OBJECTIVE

To develop consensus recommendations for anemia management in surgical patients.

METHODS

An international expert panel reviewed the current evidence and developed recommendations using modified RAND Delphi methodology.

RESULTS

The panel recommends that all patients except those undergoing minor procedures be screened for anemia before surgery. Appropriate therapy for anemia should be guided by an accurate diagnosis of the etiology. The need to proceed with surgery in some patients with anemia is expected to persist. However, early identification and effective treatment of anemia has the potential to reduce the risks associated with surgery and improve clinical outcomes. As with preoperative anemia, postoperative anemia should be treated in the perioperative period.

CONCLUSIONS

Early identification and effective treatment of anemia has the potential to improve clinical outcomes in surgical patients.

Importance of assessing biomarkers and physiological parameters of anemia-induced tissue hypoxia in the perioperative period

Anemia is associated with increased risk of Acute Kidney Injury (AKI), stroke and mortality in perioperative patients. We sought to understand the mechanism(s) by assessing the integrative physiological responses to anemia (kidney, brain), the degrees of anemia-induced tissue hypoxia, and associated biomarkers and physiological parameters. Experimental measurements demonstrate a linear relationship between blood Oxygen Content (C_aO₂) and renal microvascular PO₂ (y = 0.30x + 6.9, r² = 0.75), demonstrating that renal hypoxia is proportional to the degree of anemia. This defines the kidney as a potential oxygen sensor during anemia. Further evidence of renal oxygen sensing is demonstrated by proportional increase in serum Erythropoietin (EPO) during anemia (y = 93.806*10^-0.02, r² = 0.82). This data implicates systemic EPO levels as a biomarker of anemia-induced renal tissue hypoxia. By contrast, cerebral Oxygen Delivery (DO₂) is defended by a profound proportional increase in Cerebral Blood Flow (CBF), minimizing tissue hypoxia in the brain, until more severe levels of anemia occur. We hypothesize that the kidney experiences profound early anemia-induced tissue hypoxia which contributes to adaptive mechanisms to preserve cerebral perfusion. At severe levels of anemia, renal hypoxia intensifies, and cerebral hypoxia occurs, possibly contributing to the mechanism(s) of AKI and stroke when adaptive mechanisms to preserve organ perfusion are overwhelmed. Clinical methods to detect renal tissue hypoxia (an early warning signal) and cerebral hypoxia (a later consequence of severe anemia) may inform clinical practice and support the assessment of clinical biomarkers (i.e., EPO) and physiological parameters (i.e., urinary PO₂) of anemia-induced tissue hypoxia. This information may direct targeted treatment strategies to prevent adverse outcomes associated with anemia.

Current Practices and Guidelines for Perioperative Blood Management in Post-Bariatric Body Contouring Surgery: A Comprehensive Review of Literature

With the increase in obesity prevalence, a noticeable increase in bariatric surgeries has been reported in national and international statistics. Therefore, body contouring surgeries have increased to help individuals achieve their desired body shape. Plastic surgeons need to consider potential hematologic complications that may occur in this specific group of patients before performing body contouring surgery. This review illustrates the perioperative medical, laboratory, and management strategies needed to minimize blood loss and blood transfusion requirements during body contouring. Using Google Scholar and PubMed, a comprehensive literature review was conducted to identify articles discussing post-bariatric body contouring perioperative blood management strategies, including the effects of bariatric surgery on hemostasis as well as basic hematology and coagulation. In preoperative blood management, blood investigations aid in the early detection of electrolytes, protein, and vitamin deficiencies and anemia, resulting in the early correction of nutritional deficiencies. In order to reduce postoperative complications, surgical and anesthesia techniques, as well as intraoperative pharmacological therapy, play an essential role. Postoperative blood transfusion and restrictive transfusion thresholds are tailored to the patient's needs and depend on various physiological indicators, such as heart rate, blood pressure, urine output, and laboratory findings, such as acidosis and hematocrit level. Generally, post-bariatric body contouring blood management measures are still lacking, and more research is required to develop standardized guidelines for optimizing patient safety and satisfaction.Level of Evidence III This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Association of red blood cell transfusion volume with postoperative complications and mortality in neonatal surgery

INTRODUCTION

Red blood cell transfusion (RBCT) is commonly administered in neonatal surgical care in the absence of clear clinical indications such as active bleeding or anemia. We hypothesized that higher RBCT volumes are associated with worse postoperative outcomes.

METHODS

Neonates within the National Surgical Quality Improvement Program-Pediatric database who underwent inpatient surgery (2012-2016) were stratified by weight-based RBCT volume: <20cc/kg, 20-40cc/kg, and >40cc/kg. Postoperative complications were categorized as wound, systemic infection, central nervous system (CNS), renal, pulmonary, and cardiovascular. Multivariable logistic regression and cubic spline analysis were used to evaluate the association between RBCT volume, postoperative complications, and 30-day mortality. Sensitivity analysis was conducted by performing propensity score matching.

RESULTS

Among 9,877 neonates, 1,024 (10%) received RBCTs. Of those who received RBCT, 53% received <20cc/kg, 27% received 20-40cc/kg, and 20% received >40cc/kg. Relative to neonates who were not transfused, RBCT volume was associated with a dose-dependent increase in renal complications, CNS complications, cardiovascular complications, and 30-day mortality. With cubic spline analysis, a lone inflection point for 30-day mortality was identified at a RBCT volume of 30 - 35 cc/kg. After propensity score matching, the dose-dependent relationship was still present for 30-day mortality.

CONCLUSION

Total RBCT volume is associated with worse postoperative outcomes in neonates with a significant increase in 30-day mortality at a RBCT volume of 30 - 35 cc/kg. Future prospective studies are needed to better understand the association between large RBCT volumes and poor outcomes after neonatal surgery.

LEVEL OF EVIDENCE

Level IV, Retrospective cohort study.

ONTraC: A 20-Year History of a Successfully Coordinated Provincewide Patient Blood Management Program: Lessons Learned and Goals Achieved

Our understanding of the risks associated with perioperative anemia and transfusion, in terms of increased morbidity and mortality, has evolved over the past 2 decades. By contrast, our understanding of the potential mechanisms of injury and optimal treatment strategies remains incomplete. As such, the important role of effective patient blood management (PBM) programs, which address both the effective treatment of anemia and minimizes the need for red blood cell (RBC) transfusion, is of central importance to optimizing patient care and improving patient outcomes. We report on important clinical outcomes of the Ontario Transfusion Coordinator (ONTraC Program), a network of 25 hospital sites, working in coordination over the past 20 years. Transfusion nurse coordinators were assigned to apply multimodal best practice in PBM (including recommended changes in surgical approach; diagnosis, assessment, and treatment of anemia; and adherence to more restrictive RBC transfusion thresholds). Data were collected on various clinical parameters. We further described lessons learned and difficulties encountered in this multisite PBM initiative. A significant reduction in RBC transfusions was observed for numerous indexed surgeries. For example, RBC transfusion rates for knee arthroplasty decreased from 25% in 2002 to 0.4% in 2020. For coronary artery bypass graft (CABG) surgery, transfusion rates decreased from 60% in 2002 to 27% in 2020. We also observed a decrease in RBC units utilized per transfused patient for knee (2.1 ± 0.5 [2002] vs 1.0 ± 0.6 [2020] units per patient) and CABG surgery (3.3 ± 0.6 [2002] vs 2.3 ± 1.9 [2020] units per patient). These reductions were associated with favorable clinical outcomes, including reduced length of hospital stay (P = .00003) and a reduced rate of perioperative infections (P < .001) for nontransfused versus transfused patients. These advances have been achieved with estimated savings in the tens of millions of dollars annually. Our experience and data support the hypothesis that instituting an integrated network of transfusion nurse coordinators can provide an effective provincewide PBM program, reduce RBC transfusions, improve some patient outcomes, and reduce health care costs, as an example of a "win-win-win" medical program.

Effectiveness of intraoperative cell salvage in aseptic revision total hip arthroplasty: a single-center retrospective study

Background and study aim: Revision of total hip arthroplasty (rTHA) is associated with significant blood loss. We have used intraoperative cell savage (ICS) systematically in these patients for the last ten years. We sought to determine how often re-suspended red blood cells could be re-transfused and to identify predictors of re- transfusion. Materials and methods: Patients who underwent aseptic rTHA between January 2011 and December 2020 at our center were enrolled in this retrospective observational study. Exclusion criteria were revision for infection or tumor. The primary outcome was the successful use of ICS defined as the ability to re-transfuse at least 125 mL of ICS blood. Secondary outcome measures included re-transfused ICS blood volume, aspirated blood volume, allogenic blood transfusion, and post-operative hemoglobin level. Uni- and multi-variable logistic regressions were used to identify patients and procedure characteristics associated with successful ICS. Mann-Whitney U tests, Student’s t tests and Chi-square tests were used to compare outcomes between patients with and without successful ICS. A P value < 0.05 was considered statistically significant. Results: ICS was successful in 93 (69.9%) out of 133 patients. The extent of revision, categorized as isolated acetabulum, isolated femur, or combined revision was the only predictor of successful ICS. Postoperative hemoglobin levels as well as rate and amount of allogenic red blood cells transfusion did not differ between the groups. Conclusions: ICS is useful in most patients undergoing rTHA. Those requiring a combined revision have the greatest chance of successful re-infusion.

Anemia tolerance versus blood transfusion on long-term outcomes after colorectal cancer surgery: A retrospective propensity-score-matched analysis

Background

Perioperative anemia and transfusion are intertwined with each other, and both have adverse impacts on the survival of colorectal cancer (CRC) patients. But the treatment of anemia still relies on transfusion in several countries, which leads us to question the effects of anemia tolerance and transfusion on the long-term outcomes of CRC patients. We investigated the combined effect of preoperative anemia and postoperative anemia and of preoperative anemia and blood transfusion, which imposes a greater risk to survival, to compare the effects of anemia tolerance and transfusion on overall survival (OS) and disease-free survival (DFS) in patients undergoing CRC surgery.

Methods

A retrospective propensity-score-matched analysis included patients with CRC undergoing elective surgery between January 1, 2008, and December 31, 2014. After propensity-score matching, Kaplan–Meier survival analysis and univariable and multivariable Cox proportional hazards models were used to study the prognostic factors for survivals. In univariate and multivariate Cox regression analysis, two novel models were built.

Results

Of the 8,121 patients with CRC, 1,975 (24.3%) and 6,146 (75.7%) patients presented with and without preoperative anemia, respectively. After matching, 1,690 patients remained in each group. In the preoperative anemia and postoperative anemia model, preoperative anemia and postoperative anemia was independent risk factor for OS (HR, 1.202; 95% CI, 1.043–1.385; P=0.011) and DFS (HR, 1.210; 95% CI, 1.050–1.395; P=0.008). In the preoperative anemia and transfusion model, preoperative anemia and transfused was the most dangerous independent prognostic factor for OS (HR, 1.791; 95% CI, 1.339–2.397; P<0.001) and DFS (HR, 1.857; 95% CI, 1.389–2.483; P<0.001). In patients with preoperative anemia, the OS and DFS of patients with transfusion were worse than those of patients without transfusion (P=0.026 in OS; P=0.037 in DFS).

Conclusions

Preoperative anemia and blood transfusion imposed a greater risk to OS and DFS in patients undergoing CRC surgery, indicating that the harm associated with blood transfusion was greater than that associated with postoperative anemia. These findings should encourage clinicians to be vigilant for the timely prevention and treatment of anemia, by appropriately promoting toleration of anemia and restricting the use of blood transfusion in patients with CRC.

Iatrogenic blood loss in critical care: A prospective observational study conducted at Universitas Academic Hospital in the Free State Province, South Africa

Background

Prevention of iatrogenic blood loss is an essential component of patient blood management (PBM) in intensive care units (ICUs). The amount of iatrogenic blood loss from diagnostic phlebotomy in the ICUs at Universitas Academic Hospital, Free State Province, South Africa, is unknown.

Objectives

To quantify diagnostic phlebotomy volumes, and volumes submitted in excess for diagnostic testing in the ICU.

Methods

We conducted a prospective descriptive observational study on adults who were admitted to ICUs at a single centre over a period of 14 days. The weight of each filled phlebotomy tube was calculated using the specific gravity of blood and averages of empty phlebotomy tubes, establishing the total volume.

Results

Data from 59 participants with a median length of stay at the ICU of 3 days were analysed. The median phlebotomy volume was 7.0 mL day and 13.6 mL/ICU admission. The volume of blood required for analysis daily and ICU admission was 0.7 mL and 2.2 mL, respectively. The median phlebotomy volume in excess of the amount required for analysis daily and ICU admission was 5.05 mL and 12.11 mL, respectively.

Conclusion

While the median excess daily phlebotomy volume in this present study may seem insignificant and underestimating the true excess of phlebotomy volume, interventions to reduce phlebotomy volumes and development of a PBM guideline for appropriate phlebotomy volumes and preventing wastage of patients’ blood in the ICU is required.

Contributions of the study

We determined blood volume requirements for laboratory instrumentation, which allows phlebotomists to be cognisant of the true requirements for diagnostic tests to be undertaken accurately. We established diagnostic blood loss volumes in critical care units at a tertiary hospital in South Africa and we advocate for the introduction of patient blood management practice guidelines at local institutions.

Community Pharmacists’ Perceptions of Their Role in Provision of Anemia Management in Jazan Region, Saudi Arabia, and the Associated Barriers

Background: As a result of the lack of research exploring community pharmacists’ perspectives on anemia care, this study examined the perceived practices and barriers to anemia management services in Saudi Arabia. Methods: A questionnaire was administered to community pharmacists to validate pharmacist perceptions of their role in anemia care. Using an 11-item role test, pharmacists were asked about their perceptions of anemia management. Pharmacy anemia management barriers were explored using 20 items, and their perceptions of inter-professional contact were examined by two items. Data analyses were performed using SPSS version 22. Results: This research involved 324 community pharmacists, 62.3% of whom were males. There were significant differences between the location of pharmacy education and the perceived practice of anemia management. The most common barriers to anemia counseling were patients’ lack of knowledge about anemia, health beliefs, patients’ perceptions that their doctor takes care of them, and time constraints. The majority of respondents said they would like to have more contact with other healthcare professionals regarding the care of anemia patients. Conclusions: A positive perception of pharmacists’ role in anemia management is prevalent among Saudi pharmacists in the Jazan region. Anemia management is challenging due to time limitations and patient-related problems.

The impact of surgical trainee involvement in total hip arthroplasty: a systematic review of surgical efficacy, patient safety, and outcomes

PURPOSE

Concerns persist that trainee participation in surgical procedures may compromise patient care and potentiate adverse events and costs. We aimed to analyse the potential impact and consequences of surgical trainee involvement in total hip arthroplasty (THA) procedures in terms of surgical efficacy, patient safety, and functional outcomes.

METHODS

We systematically reviewed Medline/PubMed, EMBASE, the Cochrane library, and Scopus databases in October 2021. Eligible studies reported a direct comparison between THA cases performed with and without trainee involvement.

RESULTS

Eighteen publications met our eligibility criteria and were included in our study. The included studies reported on 142,450 THAs completed on 142,417 patients. Specifically, 48,155 and 94,295 surgeries were completed with and without trainee involvement, respectively. The mean operative times for procedures with (n = 5,662) and without (n = 14,763) trainee involvement were 106.20 and 91.41 min, respectively. Mean overall complication rates were 6.43% and 5.93% for THAs performed with (n = 4842) and without (n = 12,731) trainees. Lastly, the mean Harris Hip Scores (HHS) for THAs performed with (n = 442) and without (n = 750) trainee participation were 89.61 and 86.97, respectively.

CONCLUSION

Our systematic review confirmed previous studies' reports of increased operative time for THA cases with trainee involvement. However, based on the overall similar complication rates and functional hip scores obtained, patients should be reassured concerning the relative safety of trainee involvement in THA. Future prospective studies with higher levels of evidence are still needed to reinforce the existing evidence.

Recovery of organ-specific tissue oxygen delivery at restrictive transfusion thresholds after fluid treatment in ovine haemorrhagic shock

Background

Fluid resuscitation is the standard treatment to restore circulating blood volume and pressure after massive haemorrhage and shock. Packed red blood cells (PRBC) are transfused to restore haemoglobin levels. Restoration of microcirculatory flow and tissue oxygen delivery is critical for organ and patient survival, but these parameters are infrequently measured. Patient Blood Management is a multidisciplinary approach to manage and conserve a patient’s own blood, directing treatment options based on broad clinical assessment beyond haemoglobin alone, for which tissue perfusion and oxygenation could be useful. Our aim was to assess utility of non-invasive tissue-specific measures to compare PRBC transfusion with novel crystalloid treatments for haemorrhagic shock.

Methods

A model of severe haemorrhagic shock was developed in an intensive care setting, with controlled haemorrhage in sheep according to pressure (mean arterial pressure 30–40 mmHg) and oxygen debt (lactate > 4 mM) targets. We compared PRBC transfusion to fluid resuscitation with either PlasmaLyte or a novel crystalloid. Efficacy was assessed according to recovery of haemodynamic parameters and non-invasive measures of sublingual microcirculatory flow, regional tissue oxygen saturation, repayment of oxygen debt (arterial lactate), and a panel of inflammatory and organ function markers. Invasive measurements of tissue perfusion, oxygen tension and lactate levels were performed in brain, kidney, liver, and skeletal muscle. Outcomes were assessed during 4 h treatment and post-mortem, and analysed by one- and two-way ANOVA.

Results

Each treatment restored haemodynamic and tissue oxygen delivery parameters equivalently (p > 0.05), despite haemodilution after crystalloid infusion to haemoglobin concentrations below 70 g/L (p < 0.001). Recovery of vital organ-specific perfusion and oxygen tension commenced shortly before non-invasive measures improved. Lactate declined in all tissues and correlated with arterial lactate levels (p < 0.0001). The novel crystalloid supported rapid peripheral vasodilation (p = 0.014) and tended to achieve tissue oxygen delivery targets earlier. PRBC supported earlier renal oxygen delivery (p = 0.012) but delayed peripheral perfusion (p = 0.034).

Conclusions

Crystalloids supported vital organ oxygen delivery after massive haemorrhage, despite haemodilution to < 70 g/L, confirming that restrictive transfusion thresholds are appropriate to support oxygen delivery. Non-invasive tissue perfusion and oximetry technologies merit further clinical appraisal to guide treatment for massive haemorrhage in the context of Patient Blood Management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-022-00439-6.

Effect of severity and cause of preoperative anemia on the transfusion rate after total knee arthroplasty

This study aimed to (1) evaluate the preoperative Hb cut-off value for transfusion after unilateral and bilateral staged (1 week apart) TKAs, respectively, and (2) determine whether cause of preoperative anemia can affect transfusion rate after TKA. A total of 951 patients who underwent TKA (unilateral: 605, bilateral staged: 346) from 2016 to 2019 were reviewed retrospectively. Patient demographics, comorbidities, preoperative Hb level, surgery types, and cause of anemia were evaluated as possible risk factors. The cut-off values for preoperative Hb level to reduce transfusion after TKA were evaluated in each surgery type. Preoperative Hb level, surgery type, and cardiac disease were identified as the risk factors for transfusion after TKA, and preoperative Hb levels of 11.8 (AUC 0.88) and 12.8 (AUC 0.76) were the cut-off values for transfusion after unilateral and staged bilateral TKAs, respectively. Although transfusion rate was higher in anemia with iron deficiency (ID) group than anemia without ID group, preoperative Hb level was also lower in anemia with ID group than anemia without ID group. Single use of preoperative Hb level with different cut-offs depending on the surgery types can be useful indicator for preoperative optimization regardless of cause of anemia.

A Global Definition of Patient Blood Management

While patient blood management (PBM) initiatives are increasingly adopted across the globe as part of standard of care, there is need for a clear and widely accepted definition of PBM. To address this, an expert group representing PBM organizations, from the International Foundation for Patient Blood Management (IFPBM), the Network for the Advancement of Patient Blood Management, Haemostasis and Thrombosis (NATA), the Society for the Advancement of Patient Blood Management (SABM), the Western Australia Patient Blood Management (WAPBM) Group, and OnTrac (Ontario Nurse Transfusion Coordinators) convened and developed this definition: "Patient blood management is a patient-centered, systematic, evidence-based approach to improve patient outcomes by managing and preserving a patient's own blood, while promoting patient safety and empowerment." The definition emphasizes the critical role of informed choice. PBM involves the timely, multidisciplinary application of evidence-based medical and surgical concepts aimed at screening for, diagnosing and appropriately treating anemia, minimizing surgical, procedural, and iatrogenic blood losses, managing coagulopathic bleeding throughout the care and supporting the patient while appropriate treatment is initiated. We believe that having a common definition for PBM will assist all those involved including PBM organizations, hospital administrators, individual clinicians and policy makers to focus on the appropriate issues when discussing and implementing PBM. The proposed definition is expected to continue to evolve, making this endeavor a work in progress.

Potential of cell tracking velocimetry as an economical and portable hematology analyzer

Anemia and iron deficiency continue to be the most prevalent nutritional disorders in the world, affecting billions of people in both developed and developing countries. The initial diagnosis of anemia is typically based on several markers, including red blood cell (RBC) count, hematocrit and total hemoglobin. Using modern hematology analyzers, erythrocyte parameters such as mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), etc. are also being used. However, most of these commercially available analyzers pose several disadvantages: they are expensive instruments that require significant bench space and are heavy enough to limit their use to a specific lab and lead to a delay in results, making them less practical as a point-of-care instrument that can be used for swift clinical evaluation. Thus, there is a need for a portable and economical hematology analyzer that can be used at the point of need. In this work, we evaluated the performance of a system referred to as the cell tracking velocimetry (CTV) to measure several hematological parameters from fresh human blood obtained from healthy donors and from sickle cell disease subjects. Our system, based on the paramagnetic behavior that deoxyhemoglobin or methemoglobin containing RBCs experience when suspended in water after applying a magnetic field, uses a combination of magnets and microfluidics and has the ability to track the movement of thousands of red cells in a short period of time. This allows us to measure not only traditional RBC indices but also novel parameters that are only available for analyzers that assess erythrocytes on a cell by cell basis. As such, we report, for the first time, the use of our CTV as a hematology analyzer that is able to measure MCV, MCH, mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RDW), the percentage of hypochromic cells (which is an indicator of insufficient marrow iron supply that reflects recent iron reduction), and the correlation coefficients between these metrics. Our initial results indicate that most of the parameters measured with CTV are within the normal range for healthy adults. Only the parameters related to the red cell volume (primarily MCV and RDW) were outside the normal range. We observed significant discrepancies between the MCV measured by our technology (and also by an automated cell counter) and the manual method that calculates MCV through the hematocrit obtained by packed cell volume, which are attributed to the artifacts of plasma trapping and cell shrinkage. While there may be limitations for measuring MCV, this device offers a novel point of care instrument to provide rapid RBC parameters such as iron stores that are otherwise not rapidly available to the clinician. Thus, our CTV is a promising technology with the potential to be employed as an accurate, economical, portable and fast hematology analyzer after applying instrument-specific reference ranges or correction factors.

A model of anemic tissue perfusion after blood transfusion shows critical role of endothelial response to shear stress stimuli

Although some of the cardiovascular responses to changes in hematocrit (Hct) are not fully quantified experimentally, available information is sufficient to build a mathematical model of the consequences of treating anemia by introducing RBCs into the circulation via blood transfusion. We present such a model, which describes how the treatment of normovolemic anemia with blood transfusion impacts oxygen (O₂) delivery (DO₂, the product of blood O₂ content and arterial blood flow) by the microcirculation. Our analysis accounts for the differential response of the endothelium to the wall shear stress (WSS) stimulus, changes in nitric oxide (NO) production due to modification of blood viscosity caused by alterations of both hematocrit (Hct) and cell free layer thickness, as well as for their combined effects on microvascular blood flow and DO₂. Our model shows that transfusions of 1- and 2-unit of blood have a minimal effect on DO₂ if the microcirculation is unresponsive to the WSS stimulus for NO production that causes vasodilatation increasing blood flow and DO₂. Conversely, in a fully WSS responsive organism, blood transfusion significantly enhances blood flow and DO₂, because increased viscosity stimulates endothelial NO production causing vasodilatation. This finding suggests that evaluation of a patients' pretransfusion endothelial WSS responsiveness should be beneficial in determining the optimal transfusion requirements for treating patients with anemia.NEW & NOTEWORTHY Transfusion of 1 or 2 units of blood accounts for about 3/4 of the world blood consumption of 119 million units per year, whereas a current world demand deficit is on the order of 100 million units. Therefore, factors supporting the practice of transfusing 1 unit instead of 2 are of interest, given their potential to expand the number of interventions without increasing blood availability. Our mathematical model provides a physiological support for this practice.

Changing red blood cell transfusion practice in obstetrics and gynaecology: A before and after study of hospital-wide education

OBJECTIVES

To assess transfusion practices at a Canadian tertiary care center before and after a hospital-wide blood management educational campaign based on the Choosing Wisely toolkit.

BACKGROUND

Red blood cell (RBC) transfusions are an essential intervention in obstetrics and gynaec ology (O&G). However, with limited guidelines outlining the appropriate use of RBC transfusions, clinicians routinely transfuse based on haemoglobin values and habits.

METHODS/MATERIALS

We conducted a retrospective chart review of all patients who received a RBC transfusion while admitted under an O&G provider in two 12-month periods-before and after the intervention. The campaign consisted of Grand Rounds, formal and informal teaching, and posters placed within the hospital. We judged appropriateness from a set of criteria guided by the status of ongoing bleeding, pre-transfusion haemoglobin, and the number of units ordered simultaneously.

RESULTS

Transfusion appropriateness was poor in pre- and post-intervention periods (46% vs. 51%, p = 0.59). The overall rate of RBC transfusion was reduced from 1.8% to 1.2% (83/4610 vs. 55/4618, p = 0.02) after the intervention. There was a 52% reduction in the total number of RBC units of transfused (229 vs. 111, p < 0.001), a 33% reduction in the number of patients transfused (83 vs. 55, p = 0.016), and fewer multiple-unit transfusions without reassessment (39 vs. 13, p = 0.005).

CONCLUSION

RBC transfusion appropriateness remained low after a hospital-wide educational campaign. However, there was a marked decrease in overall transfusion use, reflecting the adoption of more restrictive transfusion practices. The low rate of transfusion appropriateness represents an opportunity for further improvement.

The Impact of Anemia on One-Year Amputation-Free Survival in Patients Undergoing Revascularization for Chronic Limb-Threatening Ischemia: A Retrospective Cohort Study

BACKGROUND

Anemia is potentially associated with increased morbidity and mortality following vascular surgery procedures. This study investigated whether peri-procedural anemia is associated with reduced 1-year amputation-free survival (AFS) in patients undergoing revascularization for chronic limb-threatening ischemia (CLTI).

METHODOLOGY

A retrospective analysis of patients diagnosed with CLTI between February 2018-February 2019, who subsequently underwent revascularization, was conducted. Hemoglobin concentration measured at index assessment was recorded and stratified by WHO criteria. Subsequent peri-procedural red blood cell transfusions (RBC) were also recorded. The primary outcome was 1-year AFS. Kaplan Meier survival analysis and Cox's proportional hazard modelling were conducted to assess the effect of anemia and peri-procedure transfusion on outcomes.

RESULTS

283 patients were analyzed, of which 148 (52.3%) were anemic. 53 patients (18.7%) underwent RBC transfusion. Patients with anemia had a significantly lower 1-year AFS (64.2% vs. 78.5%, P = 0.009). A significant difference in 1-year AFS was also observed based upon anemia severity (P = 0.008) and for patients who received RBC transfusion (45.3% vs 77.0%, P < 0.001). On multivariable analysis, moderately severe anemia was independently associated with increased risk of major amputation/death (aHR 1.90, 95% CI 1.06-3.38, P = 0.030). After adjusting for severity of baseline anemia, peri-procedural RBC transfusion was associated with a significant increase in the combined risk of major amputation/death (aHR 3.15, 95% CI 1.91-5.20, P < 0.001).

CONCLUSION

Moderately severe peri-procedural anemia and subsequent RBC transfusion are independently associated with reduced 1-year AFS in patients undergoing revascularization for CLTI. Future work should focus on investigating alternative measures to managing anemia in this cohort.

Organizational Strategies for the Management of Intravenous Iron Therapy in Non-Hospitalized Settings: A Safe Opportunity to Implement Patient Blood Management in Italy

This article analyzes the recommendations issued by the Emilia Romagna region in July 2020 on “Organizational strategies for the safe management of intravenous iron therapy in patients in non-hospitalized settings”. The objective of these recommendations is to set up safe intravenous iron administration sites outside the hospital environment across the national territory. The document facilitates the organization of methods for intravenous iron infusion that are safe for the patient and correct from a medico-legal perspective. In addition, it opens the way for the widespread use of iron infusion in the field, providing benefits to patient quality of life. This program prevents unnecessary transfusions, reduces costs, prevents overcrowding in hospitals in the event of a pandemic, and enables patient treatment in the field, thus, saving on the use of personnel.

Effectiveness and predictors of response to somatostatin analogues in patients with gastrointestinal angiodysplasias: a systematic review and individual patient data meta-analysis

BACKGROUND

Gastrointestinal angiodysplasias are vascular malformations that often cause red blood cell transfusion-dependent anaemia. Several studies suggest that somatostatin analogues might decrease rebleeding rates, but the true effect size is unknown. We therefore aimed to investigate the efficacy of somatostatin analogues on red blood cell transfusion requirements of patients with gastrointestinal angiodysplasias and to identify subgroups that might benefit the most from somatostatin analogue therapy.

METHODS

We did a systematic review and individual patient data meta-analysis. We searched MEDLINE, Embase, and Cochrane on Jan 15, 2016, with an updated search on April 25, 2021. All published randomised controlled trials and cohort studies that reported on somatostatin analogue therapy in patients with gastrointestinal angiodysplasias were eligible for screening. We excluded studies without original patient data, single case reports, small case series (ie, <10 participants), studies in which patients had a specific aetiology of gastrointestinal angiodysplasias, and studies in which somatostatin analogue therapy was initiated simultaneously with other treatment modalities. Authors of eligible studies were invited to share individual patient data. Aggregated data was used if individual patient data were not provided. The primary outcome was the mean reduction in the number of red blood cell transfusions during somatostatin analogue therapy, compared with baseline, expressed as the incidence rate ratio (IRR) and absolute mean decrease. We defined patients as either good responders (≥50% reduction in the number of red blood cell transfusions) or poor responders (<50% reduction). A mixed-effects negative binomial regression was used to account for clustering of patients and skewness in data. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO), number CRD42020213985.

FINDINGS

We identified 11 eligible studies (one randomised controlled trial and ten cohort studies) of moderate-to-high quality and obtained individual patient data from the authors of nine (82%) studies. The remaining two (18%) studies provided sufficient information in the published manuscript to extract individual patient data. In total, we analysed data from 212 patients. Somatostatin analogues reduced the number of red blood cell transfusions with an IRR of 0·18 (95% CI 0·14-0·24; p<0·0001) during a median treatment duration of 12 months (IQR 6·0-12·0) and follow-up period of 12 months (12·0-12·0), correlating with a mean absolute decrease in the number of red blood cell transfusions from 12·8 (95% CI 10·4-15·8) during baseline to 2·3 (1·9-2·9) during follow-up-ie, a reduction of 10·5 red blood cell transfusions (p<0·0001). 177 (83%) of 212 patients had a good response to somatostatin analogue therapy (defined as at least a 50% reduction in the number of red blood cell transfusions). Heterogeneity across studies was moderate (I²=53%; p=0·02). Location of gastrointestinal angiodysplasias in the stomach compared with angiodysplasias in the small bowel and colon (IRR interaction 1·92 [95% CI 1·13-3·26]; p=0·02) was associated with worse treatment response. Octreotide was associated with a better treatment response than lanreotide therapy (IRR interaction 2·13 [95% CI 1·12-4·04]; p=0·02). The certainty of evidence was high for the randomised controlled trial and low for the ten cohort studies. Adverse events occurred in 38 (18%) of 212 patients receiving somatostatin analogue therapy, with ten (5%) discontinuing this therapy because of adverse events. The most common adverse events were loose stools (seven [3%] of 212), cholelithiasis (five [2%]), flatulence (four [2%]), and administration site reactions (erythema, five [2%]).

INTERPRETATION

Somatostatin analogue therapy is safe and effective in most patients with red blood cell transfusion-dependent bleeding due to gastrointestinal angiodysplasias. Somatostatin analogue therapy is more effective in patients with angiodysplasias located in the small bowel and colon, and octreotide therapy seems to be more effective than lanreotide therapy.

FUNDING

The Netherlands Organisation for Health Research and Development and the Radboud University Medical Center.

Ascariasis, trichuriasis and fatal non-transfusion

Blood transfusion for chronic anemia can lead to acute or decompensated heart failure in patients who have fluid overload as part of their compensatory response and/or have intrinsic heart disease, and then it could be fatal in such clinical scenarios. This is the report of a case of profound chronic anemia in a young male patient, who was not transfused and then developed confusion followed by terminal cardiopulmonary arrest. Autopsy revealed severe trichuriasis to be the cause of the anemia, along with severe ascariasis, but minimal intrinsic brain disease. This supports the conclusion that anemia was the cause of the confusion, and the lesson that confusion may be a sign that the benefit of blood transfusion outweighs the risk in a patient with severe chronic anemia.

Efficacy and cost-effectiveness of universal pre-operative iron studies in total hip and knee arthroplasty

Background

The prevalence of anaemia in patients planned for total hip and knee arthroplasty is about 20%. Optimising pre-operative haemoglobin levels by iron supplementation has been shown to decrease transfusion rates, complications and associated morbidity. The need for universal screening with iron studies of all elective arthroplasty patients is not clearly defined at present.

Methods

Retrospective review of 2 sequential cohorts of patients undergoing primary hip or knee arthroplasty by a single surgeon at a single centre between January 2013 and December 2017. The first group of patients underwent pre-operative iron studies only if found to be anaemic, with a haemoglobin below 12g/dl. From January 2015, all patients irrespective of the presence of anaemia were screened with a complete iron profile before surgery. Patients with a confirmed iron deficiency were administered with intravenous iron prior to surgery. The 2 cohorts were compared with regard to blood transfusion rate post-operatively and cost efficiency for universal screening with iron studies.

Results

There was a net decrease in the allogenic blood transfusion rate from 4.76 to 2.92% when universal iron studies were introduced but the difference was not statistically significant. Obtaining universal pre-operative iron studies is cost neutral with the price of allogenic blood transfusion in a similar cohort. We also diagnosed 5 patients with occult malignancies.

Conclusions

Universal screening with pre-operative iron studies and iron infusion in elective arthroplasty patients may reduce allogenic blood requirements and is cost neutral. An additional benefit is the potential to diagnose asymptomatic malignancies. Further studies are required to show the true benefit of universal pre-operative iron screening.

Patient Blood Management Strategies to Avoid Transfusions in Body Contouring Operations: Controlled Clinical Trial

BACKGROUND

Anemia is a frequent process of morbidity and mortality in body contouring procedures. In aesthetic surgery, there are no standardized processes to minimize bleeding during surgery. For this reason, a study was designed to implement patient blood management strategies to reduce bleeding and transfusions in patients undergoing body contouring operations.

METHODS

From January of 2017 to May of 2018, a prospective cohort-type observational study was conducted, including two groups of patients undergoing single or combined body contouring procedures. The first group did not receive patient blood management strategies, whereas the second group did receive these strategies. These measures consisted of preoperative strategies to ensure the patient had optimal hemoglobin and hematocrit levels and supportive intraoperative measures to minimize blood loss. The results were validated with different statistical tests according to the variables studied.

RESULTS

A total of 409 patients were included in the study and were divided into two groups. The anthropometric and hemoglobin variables were similar in both groups. The 207 patients for whom patient blood management strategies were implemented lost an average of 1.2 g/dl less hemoglobin at 72 hours than the 202 patients for whom patient blood management strategies were not implemented (p ≤ 0.0001).

CONCLUSIONS

Patient blood management strategies, such as increasing hemoglobin before surgery, and strategies to minimize blood loss during surgery, proved to be effective at reducing bleeding in patients undergoing body contouring surgery, also decreasing the need to perform postoperative blood transfusions.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Intraoperative Red Blood Cell Transfusion Decision-making: A Systematic Review of Guidelines

OBJECTIVES

The objective of this work was to carry out a systematic review of clinical practice guidelines (CPGs) pertaining to intraoperative red blood cell (RBC) transfusions, in terms of indications, decision-making, and supporting evidence base.

SUMMARY OF BACKGROUND DATA

RBC transfusions are common during surgery and there is evidence of wide variability in practice.

METHODS

Major electronic databases (MEDLINE, EMBASE, and CINAHL), guideline clearinghouses and Google Scholar were systematically searched from inception to January 2019 for CPGs pertaining to indications for intraoperative RBC transfusion. Eligible guidelines were retrieved and their quality assessed using AGREE II. Relevant recommendations were abstracted and synthesized to allow for a comparison between guidelines.

RESULTS

Ten guidelines published between 1992 and 2018 provided indications for intraoperative transfusions. No guideline addressed intraoperative transfusion decision-making as its primary focus. Six guidelines provided criteria for transfusion based on hemoglobin (range 6.0-10.0 g/dL) or hematocrit (<30%) triggers. In the absence of objective transfusion rules, CPGs recommended considering other parameters such as blood loss (n = 7), signs of end organ ischemia (n = 5), and hemodynamics (n = 4). Evidence supporting intraoperative recommendations was extrapolated primarily from the nonoperative setting. There was wide variability in the quality of included guidelines based on AGREE II scores.

CONCLUSION

This review has identified several clinical practice guidelines providing recommendations for intraoperative transfusion. The existing guidelines were noted to be highly variable in their recommendations and to lack a sufficient evidence base from the intraoperative setting. This represents a major knowledge gap in the literature.

The Effect of Discharging Patients with Low Hemoglobin Levels on Hospital Readmission and Quality of Life after Adult Spinal Deformity Surgery

Study Design

Retrospective cohort.

Purpose

This study aims to evaluate the impact of anemia on functional outcomes, health-related quality of life (HRQoL), and early hospital readmission (EHR) rates after adult spinal deformity (ASD) surgery at the time of discharge from the hospital.

Overview of Literature

Concerns with risks of transfusion, insufficient evidence for its benefits, and the possibility of associated adverse outcomes have led to restrictive transfusion practices. Therefore, patients are discharged according to patient blood management programs that are implemented in hospitals nationwide to reduce unnecessary blood transfusions. However, not many comprehensive kinds of studies exist on the effect of postoperative anemia on functional life and complications.

Methods

Anemia severity was defined following the 2011 World Health Organization guidelines. All patients had HRQoL tests as well as complete blood counts pre- and postoperatively. EHR is the admission within 30 days of discharge and was used as the dependent parameter.

Results

This study comprised 225 surgically treated ASD patients with a median age of 62.0 years, predominantly women (80%). Of the 225 patients, 82, 137, and six had mild, moderate, and severe anemia at the time of discharge, respectively. Seventeen of the patients (mild [11, 64.7%]; moderate [5, 29.4%]; severe [1, 5.9%]) were readmitted within 30 days. The mean hemoglobin values were higher in readmitted patients (p=0.071). Infection was the leading cause of readmission (n=12), but a low hemoglobin level was not observed in any of these patients at the time of discharge. Except for Scoliosis Research Society-22 questionnaire, HRQoL improvements did not reach statistical significance in early readmitted patients in the first year after surgery.

Conclusions

The results of this study demonstrated that the occurrence and the severity of postoperative anemia are not associated with EHR in surgically treated patients with ASD. The findings of the current research suggested that clinical awareness of the parameters other than postoperative anemia may be crucial. Thus, improvements in HRQoL scores were poor in early readmitted patients 1 year after surgery.

Pre-operative anaemia and myocardial injury after noncardiac surgery: A retrospective study

BACKGROUND

Pre-operative anaemia is associated with adverse outcomes of noncardiac surgery, but its association with myocardial injury after noncardiac surgery (MINS) has not been fully investigated.

OBJECTIVE

The association between pre-operative anaemia and MINS.

DESIGN

A single-centre retrospective cohort study.

SETTING

Tertiary care referral centre.

PATIENTS

Patients with measured cardiac troponin (cTn) I levels after noncardiac surgery.

INTERVENTIONS

Patients were separated according to pre-operative anaemia (haemoglobin <13 g dl-1 in men and <12 g dl-1 in women). Anaemia was further stratified into mild and moderate-to-severe at a haemoglobin level threshold of 11 g dl-1.

MAIN OUTCOME MEASURES

The primary outcome was MINS, defined as a peak cTn I level more than 99th percentile of the upper reference limit within 30 postoperative days.

RESULTS

Data from a total of 35 170 patients were collected, including 22 062 (62.7%) patients in the normal group and 13 108 (37.3%) in the anaemia group. After propensity score matching, 11919 sets of patients were generated, and the incidence of MINS was significantly associated with anaemia [14.5 vs. 21.0%, odds ratio (OR) 1.57, 95% confidence interval (CI) 1.47 to 1.68, P < 0.001]. For the entire population, multivariable analysis showed a graded association between anaemia severity and MINS (OR 1.32, 95% CI 1.22 to 1.43, P < 0.001 for mild anaemia and OR 1.80, 95% CI 1.66 to 1.94, P < 0.001 for moderate-to-severe anaemia compared with the normal group) and a significantly higher incidence of MINS for moderate-to-severe anaemia than mild anaemia (18.6 vs. 28.6%, OR 1.37, 95% CI 1.25 to 1.50, P < 0.001). The estimated threshold for pre-operative haemoglobin associated with MINS was 12.2 g dl-1, with an area under the curve of 0.622.

CONCLUSIONS

Pre-operative anaemia was independently associated with MINS, suggesting that MINS may be related to the association between anaemia and postoperative mortality.

TRIAL REGISTRATION

SMC 2019-08-048.

Physician autonomy and patient rights: lessons from an enforced blood transfusion and the role of patient blood management

This article provides an ethical and medico-legal analysis of ruling no. 465 of 30 May 2018 issued by the Court of Termini Imerese (Palermo) and confirmed on appeal on 11 November 2020, which, in the absence of similar historical precedents in Europe, convicted a medical doctor of a crime of violent assault for having ordered the administration of a blood transfusion to a patient specifically declining blood transfusion on religious grounds. We analyse the Court's decision regarding the identification of assault in performing the blood transfusion and its decision not to accept exculpatory urgent 'necessity' as a defence. In addition, we present an updated revision of the current standard of care in transfusion medicine as well as the ethical principles governing the patient's declining of transfusion. In doing so, we highlight that respect for the patient's self-determination in declining transfusions and respect for the professional autonomy of the doctor protecting the safety and life of the patient could be equally satisfied by applying the current peer-reviewed evidence.

Sex-Specific Associations Between Preoperative Anemia and Postoperative Clinical Outcomes in Patients Undergoing Cardiac Surgery

BACKGROUND

Preoperative anemia is common in cardiac surgery, yet there were limited data describing the role of sex in the associations between anemia and clinical outcomes. Understanding these relationships may guide preoperative optimization efforts.

METHODS

This is an observational cohort study of adults undergoing isolated coronary artery bypass grafting or single- or double-valve surgery from 2008 to 2018 at a large tertiary medical center. Multivariable regression assessed the associations between preoperative hemoglobin concentrations and a primary outcome of postoperative acute kidney injury (AKI) and secondary outcomes of perioperative red blood cell (RBC) transfusion, reoperation, vascular complications (ie, stroke, pulmonary embolism, and myocardial infarction), and hospital length of stay (LOS). Each outcome was a single regression model, using interaction terms to assess sex-specific associations between hemoglobin and outcome.

RESULTS

A total of 4117 patients were included (57% men). Linear splines with sex-specific knots (13 g/dL in women and 14 g/dL in men) provided the best overall fit for preoperative hemoglobin and outcome relationships. In women, each 1 g/dL decrease in hemoglobin <13 g/dL was associated with increased odds of AKI (odds ratio = 1.49; 95% confidence interval [CI], [1.23-1.81]; P < .001), and there was no significant association between hemoglobin per 1 g/dL >13 g/dL and AKI (0.90 [0.56-1.45]; P = .67). The association between hemoglobin and AKI in men did not meet statistical significance (1.10 [0.99-1.22]; P = .076, per 1 g/dL decrease <14 g/dL; 1.00 [0.79-1.26]; P = .98 for hemoglobin per 1 g/dL >14 g/dL). In women, lower preoperative hemoglobin (per 1 g/dL decrease <13 g/dL) was associated with increased odds of RBC transfusion (2.90 [2.33-3.60]; P < .001), reoperation (1.27 [1.11-1.45]; P < .001) and a longer hospital LOS (multiplicative increase in geometric mean 1.05 [1.03-1.07]; P < .001). In men, preoperative hemoglobin (per 1 g/dL decrease <14 g/dL) was associated with increased odds of perioperative RBCs (2.56 [2.27-2.88]; P < .001) and longer hospital LOS (multiplicative increase in geometric mean 1.02 [1.01-1.04] days; P < .001) but not reoperation (0.94 [0.85-1.04]; P = .256). Preoperative hemoglobin per 1 g/dL >13 g/dL in women and 14 g/dL in men were associated with lower odds of RBCs transfusion (0.57 [0.47-0.69]; P < .001 and 0.74 [0.60-0.91]; P = .005, respectively).

CONCLUSIONS

Preoperative anemia was associated with inferior clinical outcomes after cardiac surgery. The associations between hemoglobin and outcomes were distinct for women and men, with different spline knot points identified (13 and 14 g/dL, respectively). Clinicians should consider data-driven approaches to determine preoperative hemoglobin values associated with increasing risk for adverse perioperative outcomes across sexes.

Restrictive Transfusion Strategy after Cardiac Surgery

BACKGROUND

Recent guidelines on transfusion in cardiac surgery suggest that hemoglobin might not be the only criterion to trigger transfusion. Central venous oxygen saturation (Svo2), which is related to the balance between tissue oxygen delivery and consumption, may help the decision process of transfusion. We designed a randomized study to test whether central Svo2-guided transfusion could reduce transfusion incidence after cardiac surgery.

METHODS

This single center, single-blinded, randomized controlled trial was conducted on adult patients after cardiac surgery in the intensive care unit (ICU) of a tertiary university hospital. Patients were screened preoperatively and were assigned randomly to two study groups (control or Svo2) if they developed anemia (hemoglobin less than 9 g/dl), without active bleeding, during their ICU stay. Patients were transfused at each anemia episode during their ICU stay except the Svo2 patients who were transfused only if the pretransfusion central Svo2 was less than or equal to 65%. The primary outcome was the proportion of patients transfused in the ICU. The main secondary endpoints were (1) number of erythrocyte units transfused in the ICU and at study discharge, and (2) the proportion of patients transfused at study discharge.

RESULTS

Among 484 screened patients, 100 were randomized, with 50 in each group. All control patients were transfused in the ICU with a total of 94 transfused erythrocyte units. In the Svo2 group, 34 (68%) patients were transfused (odds ratio, 0.031 [95% CI, 0 to 0.153]; P < 0.001 vs. controls), with a total of 65 erythrocyte units. At study discharge, eight patients of the Svo2 group remained nontransfused and the cumulative count of erythrocyte units was 96 in the Svo2 group and 126 in the control group.

CONCLUSIONS

A restrictive transfusion strategy adjusted with central Svo2 may allow a significant reduction in the incidence of transfusion.

EDITOR’S PERSPECTIVE