Outcome variation among Canadian trauma centres: toward a clinical prediction rule for standardizing approaches to clinical assessment of hemorrhage

Prognostic factors associated with venous thromboembolism following traumatic injury: A systematic review and meta-analysis

INTRODUCTION

Trauma patients are at increased risk of venous thromboembolism (VTE), including deep venous thrombosis and/or pulmonary embolism. We conducted a systematic review and meta-analysis summarizing the association between prognostic factors and the occurrence of VTE following traumatic injury.

METHODS

We searched the Embase and Medline databases from inception to August 2023. We identified studies reporting confounding adjusted associations between patient, injury, or postinjury care factors and risk of VTE. We performed meta-analyses of odds ratios using the random-effects method and assessed individual study risk of bias using the Quality in Prognosis Studies tool.

RESULTS

We included 31 studies involving 1,981,946 patients. Studies were predominantly observational cohorts from North America. Factors with moderate or higher certainty of association with increased risk of VTE include older age, obesity, male sex, higher Injury Severity Score, pelvic injury, lower extremity injury, spinal injury, delayed VTE prophylaxis, need for surgery, and tranexamic acid use. After accounting for other important contributing prognostic variables, a delay in the delivery of appropriate pharmacologic prophylaxis for as little as 24 to 48 hours independently confers a clinically meaningful twofold increase in incidence of VTE.

CONCLUSION

These findings highlight the contribution of patient predisposition, the importance of injury pattern, and the impact of potentially modifiable postinjury care on risk of VTE after traumatic injury. These factors should be incorporated into a risk stratification framework to individualize VTE risk assessment and support clinical and academic efforts to reduce thromboembolic events among trauma patients.

LEVEL OF EVIDENCE

Systematic Review and Meta-Analysis; Level III.

Efficacy and Safety of Anti-Xa-Guided Versus Fixed Dosing of Low Molecular Weight Heparin for Prevention of Venous Thromboembolism in Trauma Patients: A Systematic Review and Meta-Analysis

PURPOSE

Trauma patients are at high risk of venous thromboembolism (VTE). We summarize the comparative efficacy and safety of anti-Xa-guided versus fixed dosing for low molecular weight heparin (LMWH) for the prevention of VTE in adult trauma patients.

METHODS

We searched Medline and Embase from inception through June 1, 2022. We included randomized controlled trials or observational studies comparing anti-Xa-guided versus fixed dosing of LMWH for thromboprophylaxis in adult trauma patients. We incorporated primary data from 2 large observational cohorts. We pooled effect estimates using a random-effects model. We assessed risk of bias using the ROBINS-I tool for observational studies and assessed certainty of findings using GRADE methodology.

RESULTS

We included 15 observational studies involving 10,348 patients. No randomized controlled trials were identified. determined that, compared to fixed LMWH dosing, anti-Xa-guided dosing may reduce deep vein thrombosis [adjusted odds ratio (aOR); 0.52, 95% CI: 0.40-0.69], pulmonary embolism (aOR: 0.48, 95% CI: 0.30-0.78) or any VTE (aOR: 0.54, 95% CI: 0.42-0.69), though all estimates are based on low certainty evidence. There was an uncertain effect on mortality (aOR: 1.06, 95% CI: 0.85-1.32) and bleeding events (aOR: 0.84, 95% CI: 0.50-1.39), limited by serious imprecision. We used several sensitivity and subgroup analyses to confirm the validity of our assumptions.

CONCLUSION

Anti-Xa-guided dosing may be more effective than fixed dosing for prevention of deep vein thrombosis, pulmonary embolism, and VTE for adult trauma patients. These promising findings justify the need for a high-quality randomized study with the potential to deliver practice changing results.

Efficacy and Safety of Low Molecular Weight Heparin Versus Unfractionated Heparin for Prevention of Venous Thromboembolism in Trauma Patients: A Systematic Review and Meta-analysis

PURPOSE

Trauma patients are at high risk of VTE. We summarize the efficacy and safety of LMWH versus UFH for the prevention of VTE in trauma patients.

METHODS

We searched 6 databases from inception through March 12, 2021. We included randomized controlled trials (RCTs) or observational studies comparing LMWH versus UFH for thromboprophylaxis in adult trauma patients. We pooled effect estimates across RCTs and observational studies separately, using random-effects model and inverse variance weighting. We assessed risk of bias using the Cochrane tool for RCTs and the Risk of Bias in Non-Randomized Studies (ROBINS)-I tool for observational studies and assessed certainty of findings using Grading of Recommendations, Assessment, Development and Evaluations methodology.

RESULTS

We included 4 RCTs (879 patients) and 8 observational studies (306,747 patients). Based on pooled RCT data, compared to UFH, LMWH reduces deep vein thrombosis (RR 0.67, 95% CI 0.50 to 0.88, moderate certainty) and VTE (RR 0.68, 95% CI 0.51 to 0.90, moderate certainty). As compared to UFH, LMWH may reduce pulmonary embolism [adjusted odds ratio from pooled observational studies 0.56 (95% CI 0.50 to 0.62)] and mortality (adjusted odds ratio from pooled observational studies 0.54, 95% CI 0.45 to 0.65), though based on low certainty evidence. There was an uncertain effect on adverse events (RR from pooled RCTs 0.80, 95% CI 0.48 to 1.33, very low certainty) and heparin induced thrombocytopenia [RR from pooled RCTs 0.26 (95% CI 0.03 to 2.38, very low certainty)].

CONCLUSIONS

Among adult trauma patients, LMWH is superior to UFH for deep vein thrombosis and VTE prevention and may additionally reduce pulmonary embolism and mortality. The impact on adverse events and heparin induced thrombocytopenia is uncertain.

Early identification of the need for major intervention in patients with traumatic hemorrhage: development and internal validation of a simple bleeding score

BACKGROUND

Failure to rapidly identify bleeding in trauma patients leads to substantial morbidity and mortality. We aimed to develop and validate a simple bedside score for identifying bleeding patients requiring escalation of care beyond initial resuscitation.

METHODS

We included patients with major blunt or penetrating trauma, defined as those with an Injury Severity Score greater than 12 or requiring trauma team activation, at The Ottawa Hospital from September 2014 to September 2017. We used logistic regression for derivation. The primary outcome was a composite of the need for massive transfusion, embolization or surgery for hemostasis. We prespecified clinical, laboratory and imaging predictors using findings from our prior systematic review and survey of Canadian traumatologists. We used an AIC-based stepdown procedure based on the Akaike information criterion and regression coefficients to create a 5-variable score for bedside application. We used bootstrap internal validation to assess optimism-corrected performance.

RESULTS

We included 890 patients, of whom 133 required a major intervention. The main model comprised systolic blood pressure, clinical examination findings suggestive of hemorrhage, lactate level, focused assessment with sonography in trauma (FAST) and computed tomographic imaging. The C statistic was 0.95, optimism-corrected to 0.94. A simplified Canadian Bleeding (CAN-BLEED) score was devised. A score cut-off of 2 points yielded sensitivity of 97.7% (95% confidence interval [CI] 93.6 to 99.5) and specificity 73.2% (95% CI 69.9 to 76.3). An alternative version that included mechanism of injury rather than CT had lower discriminative ability (C statistic = 0.89).

CONCLUSION

A simple yet promising bleeding score is proposed to identify highrisk patients in need of major intervention for traumatic bleeding and determine the appropriateness of early transfer to specialized trauma centres. Further research is needed to evaluate the performance of the score in other settings, define interrater reliability and evaluate the potential for reduction of time to intervention.

Early identification of the need for major intervention in patients with traumatic hemorrhage: development and internal validation of a simple bleeding score

BACKGROUND

Failure to rapidly identify bleeding in trauma patients leads to substantial morbidity and mortality. We aimed to develop and validate a simple bedside score for identifying bleeding patients requiring escalation of care beyond initial resuscitation.

METHODS

We included patients with major blunt or penetrating trauma, defined as those with an Injury Severity Score greater than 12 or requiring trauma team activation, at The Ottawa Hospital from September 2014 to September 2017. We used logistic regression for derivation. The primary outcome was a composite of the need for massive transfusion, embolization or surgery for hemostasis. We prespecified clinical, laboratory and imaging predictors using findings from our prior systematic review and survey of Canadian traumatologists. We used an AIC-based stepdown procedure based on the Akaike information criterion and regression coefficients to create a 5-variable score for bedside application. We used bootstrap internal validation to assess optimism-corrected performance.

RESULTS

We included 890 patients, of whom 133 required a major intervention. The main model comprised systolic blood pressure, clinical examination findings suggestive of hemorrhage, lactate level, focused assessment with sonography in trauma (FAST) and computed tomographic imaging. The C statistic was 0.95, optimism-corrected to 0.94. A simplified Canadian Bleeding (CAN-BLEED) score was devised. A score cut-off of 2 points yielded sensitivity of 97.7% (95% confidence interval [CI] 93.6 to 99.5) and specificity 73.2% (95% CI 69.9 to 76.3). An alternative version that included mechanism of injury rather than CT had lower discriminative ability (C statistic = 0.89).

CONCLUSION

A simple yet promising bleeding score is proposed to identify highrisk patients in need of major intervention for traumatic bleeding and determine the appropriateness of early transfer to specialized trauma centres. Further research is needed to evaluate the performance of the score in other settings, define interrater reliability and evaluate the potential for reduction of time to intervention.