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The Impact of Time to Hemostatic Intervention and Delayed Care for Patients with Traumatic Hemorrhage: A Systematic Review
Lamb T, Tran A, Lampron J, Shorr R, Taljaard M, Vaillancourt C
The journal of trauma and acute care surgery. 2023
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Editor's Choice
Abstract
BACKGROUND Uncontrolled bleeding is a common cause of preventable mortality in trauma. While intuitive that delays to hemostasis may lead to worse outcomes, the impacts of these delays remain incompletely explored. This systematic review aimed to characterize the extant definitions of delayed hemostatic intervention and to quantify the impacts of delays on clinical outcomes. METHODS We searched EMBASE, MEDLINE, and Web of Science from inception to August 2022. Studies defining "delayed intervention" and those comparing times to intervention among adults presenting to hospital with blunt or penetrating injuries who required major hemostatic intervention were eligible. The co-primary outcomes were mortality and the definition of delay to hemostasis employed. Secondary outcomes included units of packed red blood cells received, length of stay in hospital, and length of stay in intensive care. RESULTS We identified 2,050 studies, with 24 studies including 10,168 patients meeting inclusion criteria. The majority of studies were retrospective observational cohort studies and most were at high risk of bias. A variety of injury patterns and hemostatic interventions were considered, with 69.6% of studies reporting a statistically significant impact of increased time to intervention on mortality. Definitions of delayed intervention ranged from ten minutes to four hours. Conflicting data were reported for impact of time on receipt of blood products, while one study found a significant impact on intensive care length of stay. No studies assessed length of stay in hospital. CONCLUSIONS The extant literature is heterogeneous with respect to injuries included, methods of hemostasis employed, and durations of delay examined. While the majority of the included studies demonstrated a statistically significant relationship between time to intervention and mortality, an evidence-informed definition of delayed intervention for bleeding trauma patients at large has not been solidified. Additional, standardized research is needed to establish targets which could reduce morbidity and mortality. LEVEL OF EVIDENCE Level IV, Systematic Review.
PICO Summary
Population
Patients with traumatic haemorrhage (24 studies, n= 10,168).
Intervention
Systematic review to characterize the extant definitions of delayed haemostatic intervention and to quantify the impacts of delays on clinical outcomes.
Comparison
Outcome
The majority of studies were retrospective observational cohort studies and most were at high risk of bias. A variety of injury patterns and haemostatic interventions were considered, with 69.6% of studies reporting a statistically significant impact of increased time to intervention on mortality. Definitions of delayed intervention ranged from ten minutes to four hours. Conflicting data were reported for impact of time on receipt of blood products, while one study found a significant impact on intensive care length of stay. No studies assessed length of stay in hospital.
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Preoperative fibrinogen level and blood transfusions in liver transplantation: A systematic review
Thibeault, F., Plourde, G., Fellouah, M., Ziegler, D., Carrier, F. M.
Transplantation reviews (Orlando, Fla.). 2023;37(4):100797
Abstract
BACKGROUND Orthotopic liver transplantation (OLT) is a major surgery often associated with significant bleeding. We conducted a systematic review to explore the association between preoperative fibrinogen level and intraoperative blood products transfusion, blood loss and clinical outcomes in patients undergoing OLT. METHODS We included observational studies conducted in patients undergoing an OLT mostly for end-stage liver disease that reported an association between the preoperative fibrinogen level and our outcomes of interest. Our primary outcome was the intraoperative red blood cell (RBC) transfusion requirements. Our secondary outcomes were intraoperative blood loss, intraoperative transfusion of any blood product, postoperative RBC transfusion, postoperative thrombotic or hemorrhagic complications, and mortality. We used a standardized search strategy. We reported our results mostly descriptively but conducted meta-analyses using random-effect models when judged feasible. RESULTS We selected 24 cohort studies reporting at least one of our outcomes. We found that a high preoperative fibrinogen level was associated with fewer intraoperative RBC and other blood products transfusions, and lower blood loss. We also found a lower overall survival in patients with a higher fibrinogen level (pooled hazard ratio [95% CI] of 1.50 [1.23 to 1.84]; 5 studies, n = 1012, I(2) = 48%). Only one study formally explored a fibrinogen level threshold effect. Overall, reporting was heterogeneous, and risk of bias was variable mostly because of uncontrolled confounding. CONCLUSION A higher preoperative fibrinogen level was associated with fewer intraoperative RBC and other blood products transfusions, lower blood loss, and higher mortality. Further studies may help clarify observed associations and inform guidelines.
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A systematic review on viscoelastic testing in subarachnoid haemorrhage patients
Tjerkstra, M. A., Wolfs, A. E., Verbaan, D., Vandertop, W. P., Horn, J., Müller, M. C. A., Juffermans, N. P.
World Neurosurgery. 2023
Abstract
OBJECTIVES Bleeding and thromboembolic complications frequently occur following subarachnoid haemorrhage (SAH) and substantially contribute to poor outcome. Viscoelastic testing could be used for detection of coagulopathies following SAH. This review summarizes literature on the utility of viscoelastic testing to detect coagulopathy in SAH patients and explores whether viscoelastic parameters are associated with SAH-related complications and clinical outcome. MATERIALS AND METHODS PUBMED, EMBASE and Google Scholar were systematically searched on August 18(th), 2022. Two authors independently selected studies which performed viscoelastic testing in SAH patients and assessed the quality of studies using the Newcastle Ottawa Scale or a previously published framework for quality assessment. Data was meta-analysed if methodologically possible. RESULTS The search yielded 19 studies (1160 SAH patients). Pooling of data including all relevant studies was not possible for any of the outcome measurements due to methodological differences. Thirteen of 19 studies evaluated the association of coagulation profiles and SAH, of which 11 studies showed a hypercoagulable profile. Rebleeding was associated with platelet dysfunction, deep venous thrombosis was associated with faster clot initiation and both delayed cerebral ischemia and poor outcome were associated with increased clot strength. CONCLUSIONS This explorative review shows that SAH patients frequently have a hypercoagulable profile. TEG- and ROTEM-parameters are associated with rebleeding, delayed cerebral ischemia, deep venous thrombosis and poor clinical outcome after SAH, however more research on the subject is needed. Future studies should focus on determining the optimal time frame and cut-off values for TEG or ROTEM to predict these complications.
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Effects of hypoxia-inducible factor prolyl hydroxylase inhibitors versus erythropoiesis-stimulating agents on iron metabolism and inflammation in patients undergoing dialysis: A systematic review and meta-analysis
Zheng Q, Zhang P, Yang H, Geng Y, Tang J, Kang Y, Qi A, Li S
Heliyon. 2023;9(4):e15310
Abstract
AIMS: This study aimed to evaluate the effects of hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) on iron metabolism and inflammation in dialysis-dependent chronic kidney disease (DD-CKD) patients. METHODS PubMed, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov websites were searched for randomized controlled trials (RCTs) investigating HIF-PHIs versus ESAs for DD-CKD patients. KEY FINDINGS Twenty studies with 14,737 participants were included in the meta-analysis, which demonstrated no significant difference in the effect of transferrin saturation and ferritin between HIF-PHIs and the ESAs group (MD, 0.65; 95%CI, -0.45 to 1.75; very low certainty; SMD, -0.03; 95% CI, -0.13 to 0.07; low certainty). However, HIF-PHIs significantly increased the iron (MD, 2.30; 95% CI, 1.40 to 3.20; low certainty), total iron-binding capacity (SMD, 0.82; 95% CI, 0.66 to 0.98; low certainty), and transferrin (SMD, 0.90; 95%CI, 0.74 to 1.05; moderate certainty) levels when compared with the ESAs group. In contrast, the hepcidin level and dosage of intravenous iron were significantly decreased in the HIF-PHIs group compared with the ESAs group (MD, -15.06, 95%CI, -21.96 to -8.16; low certainty; MD, -18.07; 95% CI, -30.05 to -6.09; low certainty). The maintenance dose requirements of roxadustat were independent of baseline CRP or hsCRP levels with respect to the effect on inflammation. SIGNIFICANCE HIF-PHIs promote iron utilization and reduce the use of intravenous iron therapy. Furthermore, HIF-PHIs, such as roxadustat, maintain the erythropoietic response independent of the inflammatory state. Thus, HIF-PHIs may be an alternative treatment strategy for anemia in DD-CKD patients, where ESA is hyporesponsive due to iron deficiency and inflammation.
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Small-Volume Blood Collection Tubes to Reduce Transfusions in Intensive Care: The STRATUS Randomized Clinical Trial
Siegal, D. M., Belley-Côté, E. P., Lee, S. F., Hill, S., D'Aragon, F., Zarychanski, R., Rochwerg, B., Chassé, M., Binnie, A., Honarmand, K., et al
Jama. 2023
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Editor's Choice
Abstract
IMPORTANCE Blood collection for laboratory testing in intensive care unit (ICU) patients is a modifiable contributor to anemia and red blood cell (RBC) transfusion. Most blood withdrawn is not required for analysis and is discarded. OBJECTIVE To determine whether transitioning from standard-volume to small-volume vacuum tubes for blood collection in ICUs reduces RBC transfusion without compromising laboratory testing procedures. DESIGN, SETTING, AND PARTICIPANTS Stepped-wedge cluster randomized trial in 25 adult medical-surgical ICUs in Canada (February 5, 2019 to January21, 2021). INTERVENTIONS ICUs were randomized to transition from standard-volume (n = 10 940) to small-volume tubes (n = 10 261) for laboratory testing. MAIN OUTCOMES AND MEASURES The primary outcome was RBC transfusion (units per patient per ICU stay). Secondary outcomes were patients receiving at least 1 RBC transfusion, hemoglobin decrease during ICU stay (adjusted for RBC transfusion), specimens with insufficient volume for testing, length of stay in the ICU and hospital, and mortality in the ICU and hospital. The primary analysis included patients admitted for 48 hours or more, excluding those admitted during a 5.5-month COVID-19-related trial hiatus. RESULTS In the primary analysis of 21 201 patients (mean age, 63.5 years; 39.9% female), which excluded 6210 patients admitted during the early COVID-19 pandemic, there was no significant difference in RBC units per patient per ICU stay (relative risk [RR], 0.91 [95% CI, 0.79 to 1.05]; P = .19; absolute reduction of 7.24 RBC units/100 patients per ICU stay [95% CI, -3.28 to 19.44]). In a prespecified secondary analysis (n = 27 411 patients), RBC units per patient per ICU stay decreased after transition from standard-volume to small-volume tubes (RR, 0.88 [95% CI, 0.77 to 1.00]; P = .04; absolute reduction of 9.84 RBC units/100 patients per ICU stay [95% CI, 0.24 to 20.76]). Median decrease in transfusion-adjusted hemoglobin was not statistically different in the primary population (mean difference, 0.10 g/dL [95% CI, -0.04 to 0.23]) and lower in the secondary population (mean difference, 0.17 g/dL [95% CI, 0.05 to 0.29]). Specimens with insufficient quantity for analysis were rare (≤0.03%) before and after transition. CONCLUSIONS AND RELEVANCE Use of small-volume blood collection tubes in the ICU may decrease RBC transfusions without affecting laboratory analysis. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT03578419.
PICO Summary
Population
Adult patients in 25 medical-surgical intensive care units (ICU) in Canada (n= 21,201).
Intervention
Small-volume vacuum tubes for blood collection (n= 10,261).
Comparison
Standard-volume vacuum tubes for blood collection (n= 10,940).
Outcome
In the primary analysis of 21,201 patients, which excluded 6,210 patients admitted during the early COVID-19 pandemic, there was no significant difference in red blood cell (RBC) units per patient per ICU stay (relative risk [RR] 0.91; 95% CI [0.79, 1.05]; absolute reduction of 7.24 RBC units/100 patients per ICU stay 95% CI [-3.28, 19.44]). In a prespecified secondary analysis (n= 27,411 patients), RBC units per patient per ICU stay decreased after transition from standard-volume to small-volume tubes (RR 0.88; 95% CI [0.77, 1.00]; absolute reduction of 9.84 RBC units/100 patients per ICU stay 95% CI [0.24, 20.76]). Median decrease in transfusion-adjusted haemoglobin was not statistically different in the primary population (mean difference 0.10 g/dL; 95% CI [-0.04, 0.23]) and lower in the secondary population (mean difference 0.17 g/dL; 95% CI [0.05, 0.29]). Specimens with insufficient quantity for analysis were rare (≤0.03%) before and after transition.
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Cardiac surgery in Jehovah's Witnesses patients and association with peri-operative outcomes: a systematic review and meta-analysis
Vitolo M, Mei DA, Cimato P, Bonini N, Imberti JF, Cataldo P, Menozzi M, Filippini T, Vinceti M, Boriani G
Current problems in cardiology. 2023;:101789
Abstract
BACKGROUND Strategies for blood conservation, coupled with a careful preoperative assessment, may be applied to Jehovah's Witnesses (JW) patients who are candidates for cardiac surgery interventions. There is a need to assess clinical outcomes and safety of bloodless surgery in JW patients undergoing cardiac surgery. METHODS We performed a systematic review and meta-analysis of studies comparing JW patients with controls undergoing cardiac surgery. The primary endpoint was short-term mortality (in-hospital or 30-day mortality). Peri-procedural myocardial infarction, re-exploration for bleeding, pre-and post-operative Hb levels and cardiopulmonary bypass (CPB) time were also analyzed. RESULTS A total of 10 studies including 2,302 patients were included. The pooled analysis showed no substantial differences in terms of short-term mortality among the two groups (OR 1.13, 95% CI 0.74-1.73, I(2)=0%). There were no differences in peri-operative outcomes among JW patients and controls (OR 0.97, 95% CI 0.39-2.41, I(2)=18% for myocardial infarction; OR 0.80, 95% CI 0.51-1.25, I(2)=0% for re-exploration for bleeding). JW patients had a higher level of pre-operative Hb (Standardized Mean Difference [SMD] 0.32, 95% CI 0.06-0.57) and a trend toward a higher level of post-operative Hb (SMD 0.44, 95% CI -0.01-0.90). A slightly lower CPB time emerged in JWs compared with controls (SMD -0.11, 95% CI -0.30-0.07). CONCLUSIONS JW patients undergoing cardiac surgery, with avoidance of blood transfusions, did not have substantially different peri-operative outcomes compared with controls, with specific reference to mortality, myocardial infarction, and re-exploration for bleeding. Our results support the safety and feasibility of bloodless cardiac surgery, applying patient blood management strategies.
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Comparison of quantitative and calculated postpartum blood loss after vaginal delivery
Madar, H., Sentilhes, L., Goffinet, F., Bonnet, M. P., Rozenberg, P., Deneux-Tharaux, C.
American journal of obstetrics & gynecology MFM. 2023;:101065
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Editor's Choice
Abstract
BACKGROUND Because there is no consensual method of assessing postpartum blood loss, the comparability and relevance of the postpartum hemorrhage-related literature is questionable. Quantitative blood loss assessment using a volumetric technique with a graduated collector bag has been proposed to overcome limitations of intervention-based outcomes but remains partly subjective and potentially biased by amniotic fluid or missed out-of-bag losses. Calculated blood loss based on laboratory parameters has been published and used as an objective method expected to reflect total blood loss, but few studies have compared quantitative with calculated blood loss. OBJECTIVE This study aimed to compare the distribution of postpartum blood loss after vaginal delivery assessed by two methods - quantitative and calculated blood loss - and the incidence of abnormal blood loss with each method. STUDY DESIGN The data came from the merged database of 3 multicenter, randomized controlled trials, all testing different interventions to prevent postpartum blood loss in individuals with a singleton live fetus ≥ 35 weeks, born vaginally. All 3 trials measured blood loss volume by using a graduated collector bag. Hematocrit was measured in the eighth or ninth month of gestation and on day 2 postpartum. The two primary outcomes were: quantitative blood loss defined by the total volume of blood loss measured in a graduated collector bag, and calculated blood loss mathematically defined from the peripartum hematocrit change (estimated blood volume × [(antepartum hematocrit - postpartum hematocrit)/antepartum hematocrit], where estimated blood volume (mL) = booking weight (kg) × 85). We modelled the association between positive quantitative blood loss and positive calculated blood loss with polynomial regression and calculated the Spearman correlation coefficient. RESULTS Among the 8341 individuals included in this analysis, the median quantitative blood loss (100 mL, interquartile range 50-275) was significantly lower than the median calculated blood loss (260 mL, interquartile range 0-630) (P<.05). The incidence of abnormal blood loss was lower with quantitative blood loss than calculated blood loss for blood loss ≥ 500 mL, ≥ 1000 mL and ≥ 2000 mL, respectively, it was 9.6% (799/8341) vs 32.3% (2691/8341), 2.1% (176/8341) vs 11.5% (959/8341), and 0.1% (10/8341) vs 1.4% (117/8341); (P<.05). Quantitative blood loss and calculated blood loss were significantly but moderately correlated (Spearman coefficient=0.44; P<.05). The association between them was not linear, and their difference tended to increase with blood loss. Negative calculated blood loss values occurred in 23% (1958/8341) of individuals; among them, more than 99% (1939/1958) had quantitative blood loss ≤ 500 mL. CONCLUSION Quantitative and calculated blood loss were significantly but moderately correlated after vaginal delivery. However, clinicians should be aware that quantitative blood loss is lower than calculated blood loss, with a difference that tended to rise as blood loss increased.
PICO Summary
Population
Patients who gave birth vaginally, participating in the TRACOR, CYTOCINON, and TRAAP randomised controlled trials (RCTs) in several French maternity units (n= 8,341).
Intervention
This study aimed to compare the distribution of postpartum blood assessed by two methods - quantitative and calculated blood loss - and the incidence of abnormal blood loss with each method.
Comparison
Outcome
The data came from 3 RCTs testing different interventions to prevent postpartum blood loss. All 3 trials measured blood loss volume by using a graduated collector bag. The authors modelled the association between positive quantitative blood loss and positive calculated blood loss with polynomial regression and calculated the Spearman correlation coefficient. The median quantitative blood loss (100 mL, IQR= 50, 275) was significantly lower than the median calculated blood loss (260 mL, IQR= 0, 630). The incidence of abnormal blood loss was lower with quantitative blood loss than calculated blood loss. Quantitative blood loss and calculated blood loss were significantly but moderately correlated (Spearman coefficient= 0.44). The association between them was not linear, and their difference tended to increase with blood loss. Negative calculated blood loss values occurred in 23% (1,958/8,341) of individuals; among them, more than 99% (1,939/1,958) had quantitative blood loss ≤ 500 mL.
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The Effectiveness of Student-Led Ward Round Training on Knowledge Acquisition, Critical Thinking Ability, and Self-Confidence of Acute Upper Gastrointestinal Bleeding for Nursing Students
Liu N, Zheng Z, Liao J, Li J, Yang Z, Lai X
Advances in medical education and practice. 2023;14:21-30
Abstract
INTRODUCTION Nursing knowledge, critical thinking ability, and self-perceived confidence are imperative to nursing skills in professional nursing practice. Therefore, nurse educators are required to use teaching strategies that will help promote their knowledge, critical thinking, and self-confidence in complex contents such as the nursing of acute upper gastrointestinal bleeding (AUGIB). PURPOSE This study compares the effect of student-led and instructor-led ward-round training methods on knowledge acquisition, critical thinking ability, and self-perceived confidence during AUGIB sessions. METHODS Forty nursing students in the first year of the Emergency Nursing Residency Program were randomly divided into a student-led ward round training group (SG) and an instructor-led ward round training group (IG) with a ratio of 1:1. A knowledge quiz, critical thinking ability test, and self-perceived confidence questionnaire were performed before and after the ward round training to assess both groups of students for their knowledge acquisition, critical thinking ability, and self-perceived confidence improvement. Feedback questionnaires were conducted after the training to evaluate students' perspectives and interests concerning the teaching module. RESULTS The scores of the post-training quiz were significantly higher than that of the pre-training quiz in both the SG (44.10±2.92 vs 31.10±4.27, p<0.001) and IG (32.35±2.21 vs 30.55±2.24, p=0.01). In the post-training quiz, scores achieved by the students from the SG (44.10±2.92) were significantly higher than those achieved by the students from the IG (32.35±2.21, p< 0.001). The level of self-perceived confidence improved significantly after ward round training in the SG (p< 0.001). However, there was no statistically significant difference in the IG with respect to the change from pre- to post-training (p=0.43).The students' critical thinking ability improved significantly in the SG (14.95±2.58 vs 7.10±1.79, p<0.001), while no significant improvement was found in the IG (7.91±2.28 vs 6.52±2.21, p=0.07) after ward round training. CONCLUSION The teaching method of SWRT improves nursing students' knowledge acquisition, critical thinking ability, and self-perceived confidence in AUGIB.
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Evaluating the costs and consequences of computerized clinical decision support systems in hospitals: a scoping review and recommendations for future practice
White NM, Carter HE, Kularatna S, Borg DN, Brain DC, Tariq A, Abell B, Blythe R, McPhail SM
Journal of the American Medical Informatics Association : JAMIA. 2023
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Editor's Choice
Abstract
OBJECTIVE Sustainable investment in computerized decision support systems (CDSS) requires robust evaluation of their economic impacts compared with current clinical workflows. We reviewed current approaches used to evaluate the costs and consequences of CDSS in hospital settings and presented recommendations to improve the generalizability of future evaluations. MATERIALS AND METHODS A scoping review of peer-reviewed research articles published since 2010. Searches were completed in the PubMed, Ovid Medline, Embase, and Scopus databases (last searched February 14, 2023). All studies reported the costs and consequences of a CDSS-based intervention compared with current hospital workflows. Findings were summarized using narrative synthesis. Individual studies were further appraised against the Consolidated Health Economic Evaluation and Reporting (CHEERS) 2022 checklist. RESULTS Twenty-nine studies published since 2010 were included. Studies evaluated CDSS for adverse event surveillance (5 studies), antimicrobial stewardship (4 studies), blood product management (8 studies), laboratory testing (7 studies), and medication safety (5 studies). All studies evaluated costs from a hospital perspective but varied based on the valuation of resources affected by CDSS implementation, and the measurement of consequences. We recommend future studies follow guidance from the CHEERS checklist; use study designs that adjust for confounders; consider both the costs of CDSS implementation and adherence; evaluate consequences that are directly or indirectly affected by CDSS-initiated behavior change; examine the impacts of uncertainty and differences in outcomes across patient subgroups. DISCUSSION AND CONCLUSION Improving consistency in the conduct and reporting of evaluations will enable detailed comparisons between promising initiatives, and their subsequent uptake by decision-makers.
PICO Summary
Population
Patients in hospital settings – including those receiving inpatient, emergency, or ambulatory care (29 studies).
Intervention
Computerized decision support systems (CDSS) based intervention.
Comparison
Current hospital workflows.
Outcome
Studies evaluated CDSS for adverse event surveillance (5 studies), antimicrobial stewardship (4 studies), blood product management (8 studies), laboratory testing (7 studies), and medication safety (5 studies). All studies evaluated costs from a hospital perspective but varied based on the valuation of resources affected by CDSS implementation, and the measurement of consequences.
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Systematic review highlights high risk of bias of clinical prediction models for blood transfusion in patients undergoing elective surgery
Dhiman P, Ma J, Gibbs VN, Rampotas A, Kamal H, Arshad SS, Kirtley S, Doree C, Murphy MF, Collins GS, et al
Journal of clinical epidemiology. 2023
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Editor's Choice
Abstract
BACKGROUND Blood transfusion can be a lifesaving intervention after perioperative blood loss. Many prediction models have been developed to identify patients most likely to require blood transfusion during elective surgery, but it is unclear whether any are suitable for clinical practice. STUDY DESIGN AND SETTING We conducted a systematic review, searching MEDLINE, Embase, PubMed, The Cochrane Library, Transfusion Evidence Library, Scopus, and Web of Science databases for studies reporting the development or validation of a blood transfusion prediction model in elective surgery patients between 01/01/2000 to 30/06/2021. We extracted study characteristics, discrimination performance (c-statistics) of final models and data which we used to perform risk of bias assessment using the Prediction model Risk Of Bias ASsessment Tool (PROBAST). RESULTS We reviewed 66 studies (72 developed and 48 externally validated models). Pooled c-statistics of externally validated models ranged from 0.67 to 0.78. Most developed and validated models were at high risk of bias due to handling of predictors, validation methods, and too small sample sizes. CONCLUSION Most blood transfusion prediction models are at high risk of bias and suffer from poor reporting and methodological quality, which must be addressed before they can be safely used in clinical practice.
PICO Summary
Population
Patients undergoing elective surgery (66 studies).
Intervention
Blood transfusion prediction models used perioperatively.
Comparison
Outcome
This systematic review appraised 120 prediction models developed or validated for predicting blood transfusion in elective surgery (72 developed and 48 externally validated models). Pooled c-statistics of externally validated models ranged from 0.67 to 0.78. Most developed and validated models were at high risk of bias due to handling of predictors, validation methods, and too small sample sizes.