Venous thromboembolism in trauma: an update for the intensive care unit practitioner

Utility of coagulation analyses to assess thromboprophylaxis with dalteparin in intensive care unit patients

BACKGROUND

The aim of this study was to evaluate the utility of coagulation analyses to assess thromboprophylaxis with dalteparin in intensive care unit (ICU) patients.

METHODS

Prospective observational study of ICU patients receiving dalteparin prophylaxis at Oslo University Hospital in Norway. Trough and peak antithrombin, protein C, anti-factor Xa activity (aFXa), d-dimer, thromboelastography, calibrated automated thrombogram and microparticles were analysed. Levels were compared in patients with and without venous thromboembolism (VTE), major bleeding, acute kidney injury (AKI) with use of renal replacement therapy (RRT) and variable dalteparin dose.

RESULTS

Among 50 included patients (76% male, mean age 62 years) five (10%) developed VTE and eight (16%) major bleeding. Median through aFXa level was 0.03 (0.02-0.05) IU/mL, and 48 (96%) of patients were within and two (4%) above target range. Peak aFXa level was 0.21 (0.13-0.29) IU/mL, the number of patients below, within and above prophylactic range were 21 (42%), 25 (50%) and four (8%). Peak aFXa levels were similar in patients with and without VTE (0.18 vs 0.21 IU/L, P = .72), major bleeding (0.22 vs 0.21 IU/mL, P = .38) and AKI with RRT (0.18 vs 0.24, P = .13), but lower in patients receiving dalteparin 5000 IU od compared to 7500 IU od (0.19 vs 0.30 IU/mL, P < .01).

CONCLUSIONS

Intensive care unit patients receiving dalteparin prophylaxis had half of patients within prophylactic peak aFXa target range. Peak aFXa levels was affected by administered dalteparin dose, but not presence of VTE, major bleeding or AKI with RRT.

Cardiovascular ultrasonography detection of embolic sources in trauma

Venous thromboembolism (deep vein thrombosis and pulmonary embolism) and bone cement implantation syndrome are major sources of embolic events in trauma patients. In these patients, embolic events due to venous thromboembolism and bone cement implantation syndrome have been detected with cardiac and vascular ultrasonography in the emergency setting, during the perioperative period, and in the intensive care unit. This article discusses the ultrasonography modalities and imaging findings of embolic events related to venous thromboembolism and bone cement implantation syndrome. The aim is to present a short review with exceptional illustrations that can enable physicians to identify sources of emboli in trauma patients with cardiovascular ultrasonography.

Outcomes in neurosurgical patients who develop venous thromboembolism: a review of the RIETE registry

OBJECTIVES

Registro Informatizado de Enfermedad TromboEmbólica (RIETE) database was used to investigate whether neurosurgical patients with venous thromboembolism (VTE) were more likely to die of bleeding or VTE and the influence of anticoagulation on these outcomes.

METHODS

Clinical characteristics, treatment details, and 3-month outcomes were assessed in those who developed VTE after neurosurgery.

RESULTS

Of 40 663 patients enrolled, 392 (0.96%) had VTE in less than 60 days after neurosurgery. Most patients in the cohort (89%) received initial therapy with low-molecular-weight heparin, (33% received subtherapeutic doses). In the first week, 10 (2.6%) patients died (8 with pulmonary embolism [PE], no bleeding deaths; P = .005). After the first week, 20 (5.1%) patients died (2 with fatal bleeding, none from PE). Overall, this cohort was more likely to develop a fatal PE than a fatal bleed (8 vs 2 deaths, P = .058).

CONCLUSIONS

Neurosurgical patients developing VTE were more likely to die from PE than from bleeding in the first week, despite anticoagulation.

Subclavian central venous catheter-related thrombosis in trauma patients: incidence, risk factors and influence of polyurethane type

Introduction

The incidence of deep venous thrombosis (DVT) related to a central venous catheter varies considerably in ICUs depending on the population included. The aim of this study was to determine subclavian central venous catheter (SCVC)-related DVT risk factors in severely traumatized patients with regard to two kinds of polyurethane catheters.

Methods

Critically ill trauma patients needing a SCVC for their usual care were prospectively included in an observational study. Depending on the month of inclusion, patients received one of the two available products in the emergency unit: either an aromatic polyurethane SCVC or an aliphatic polyurethane SCVC. Patients were screened weekly by ultrasound for SCVC-related DVT. Potential risk factors were collected, including history-related, trauma-related and SCVC-related characteristics.

Results

A total of 186 patients were included with a median Injury Severity Sore of 30 and a high rate of severe brain injuries (21% of high intracranial pressure). Incidence of SCVC-related DVT was 37% (95% confidence interval: 26 to 40) in patients or 20/1,000 catheter-days. SCVC-related DVT occurred within 8 days in 65% of cases. There was no significant difference in DVT rates between the aromatic polyurethane and aliphatic polyurethane SCVC groups (38% vs. 36%). SCVC-related DVT independent risk factors were age >30 years, intracranial hypertension, massive transfusion (>10 packed red blood cell units), SCVC tip position in the internal jugular or in the innominate vein, and ipsilateral jugular catheter.

Conclusion

SCVC-related DVT concerned one-third of these severely traumatized patients and was mostly clinically silent. Incidence did not depend on the type of polyurethane but was related to age >30 years, intracranial hypertension or misplacement of the SCVC. Further studies are needed to assess the cost-effectiveness of routine screening in these patients in whom thromboprophylaxis may be hazardous.

Optional inferior vena cava filters in the trauma patient

Trauma patients are at exceedingly high risk of development of venous thromboembolism (VTE) including deep venous thrombosis and pulmonary embolism (PE). The epidemiology of VTE in trauma patients is reviewed. PE is thought to be the third major cause of death after trauma in those patients who survive longer than 24 hours after onset of injury. In fact, patients recovering from trauma have the highest rate of VTE among all subgroups of hospitalized patients. Various prophylactic and surveillance methods have been evaluated and found helpful in certain situations, but VTE complications can occur despite such measures. Therapeutic and prophylactic uses of inferior vena cava (IVC) filters in trauma patients are reviewed. Prophylactic IVC filter use is revealed to be a controversial subject with valid arguments on both sides of the issue. With the lack of prospective randomized trials of IVC filter use in trauma, it is impossible to make evidence-based recommendations. Unfortunately, two sets of guidelines are available for insertion of filters in trauma patients, with conflicting recommendations. The introduction of retrievable IVC filters seems to offer a unique solution for VTE protection in the trauma patient population, which often consists of younger members of our population. Lastly, current generations of FDA-approved retrieval filters are discussed.

Rates of symptomatic venous thromboembolism in US surgical patients: a retrospective administrative database study

US national performance measures may reduce the burden of venous thromboembolism (VTE) in surgical patients. To characterize the VTE rate in US surgical patients, and identify real-world independent VTE risk-factors, a national managed-care database was analyzed. 172,320 eligible surgical discharges (23.9% orthopedic, 76.1% abdominal surgery) from the PharMetrics database (January 2001-December 2005) were evaluated. The rate of thromboprophylaxis was low in orthopedic (40.5%) and abdominal (1.8%) surgery discharges, with the event rates of symptomatic VTE in these groups being 4.7% and 3.1%, respectively. The median time to VTE was 51 days: the majority of VTE events occurred post-discharge. Independent predictors of VTE included prior VTE (odds ratio [OR] 10.2; 95% CI: 9.2-11.4), and orthopedic versus abdominal surgery (OR 1.4; 95% CI: 1.4-1.6). Patients undergoing orthopedic or abdominal surgery remain at-risk for VTE. Implementation of national performance measures may help reduce the burden of VTE.

Venous thromboembolism as a marker of quality of care in trauma

BACKGROUND

Venous thromboembolism (VTE) is reported to occur among 7% to 58% of trauma patients. Variability in VTE rates might reflect differences in case mix and quality of care, but also screening practices or data capture. We explored the variation in VTE rates across trauma centers to determine its use as a measure of the quality of patient care.

STUDY DESIGN

The National Trauma Data Bank (version 7.1, admission year 2006) was used to capture a cohort at risk for VTE. Crude and adjusted rates of VTE were determined, and the observed and expected rates were compared across centers. Outlier hospitals were defined as those with considerably more (or fewer) patients than expected. We then assessed the level of concordance between outlier status for deep vein thrombosis (DVT) and pulmonary embolism (PE). Intraclass correlation coefficients (ICC) were calculated to evaluate for the presence of a "center" effect using multilevel modeling.

RESULTS

The 22,421 patients met inclusion criteria from 30 trauma centers. There was marked variability in the rate of VTE across centers, ranging from 0.2% to 13.3%, which was more pronounced for DVT (0.2% to 13.1%) than for PE (0% to 1.7%). There was poor concordance for DVT and PE outlier status. Intraclass correlation coefficient was four times greater for DVT (0.23) than for PE (0.06).

CONCLUSIONS

There was substantial variation in rates of VTE across trauma centers. There was no relationship between DVT and PE outlier status, which is counter to the understanding of the biologic relationship between the two. Lastly, the very low Intraclass correlation coefficient for PE compared with DVT suggests that to a large extent, practice variation has very little impact on PE rates. In light of these findings and concerns about patient ascertainment of DVT, VTE rates might not be a useful measure of quality of care.