Prophylactic Inferior Vena Cava Filters: Do They Make a Difference in Trauma Patients?

Perioperative management of acetabular and pelvic fractures: evidence-based recommendations

PURPOSE

The American Academy of Orthopaedic Surgeons does not currently provide clinical practice guidelines for management of PAF. Accordingly, this article aims to review and consolidate the relevant historical and recent literature in important topics pertaining to perioperative management of PAF.

METHODS

A thorough literature review using PubMed, Cochrane and Embase databases was performed to assess preoperative, intraoperative and postoperative management of PAF fracture. Topics reviewed included: time from injury to definitive fixation, the role of inferior vena cava filters (IVCF), tranexamic acid (TXA) use, intraopoperative cell salvage, incisional negative pressure wound therapy (NPWT), intraoperative antibiotic powder use, heterotopic ossification prophylaxis, and pre- and postoperative venous thromboembolism (VTE) prophylaxis.

RESULTS

A total of 126 articles pertaining to the preoperative, intraoperative and postoperative management of PAF were reviewed. Articles reviewed by topic include 13 articles pertaining to time to fixation, 23 on IVCF use, 14 on VTE prophylaxis, 20 on TXA use, 10 on cell salvage, 10 on iNPWT 14 on intraoperative antibiotic powder and 20 on HO prophylaxis. An additional eight articles were reviewed to describe background information. Five articles provided information for two or more treatment modalities and were therefore included in multiple categories when tabulating the number of articles reviewed per topic.

CONCLUSION

The literature supports the use of radiation therapy for HO prophylaxis, early (< 5 days from injury) surgical intervention and the routine use of intraoperative TXA. The literature does not support the routine use of iNPWT or IVCF. There is inadequate information to make a recommendation regarding the use of cell salvage and wound infiltration with antibiotic powder. While the routine use of chemical VTE prophylaxis is recommended, there is insufficient evidence to recommend the optimal agent and duration of therapy.

Perioperative Management of Incidental Pulmonary Embolisms on Trauma CT Scans: A Narrative Review

Unsuspected pulmonary embolism (PE) may be identified on an initial trauma computed tomography (CT) scan. The clinical importance of these incidental PEs remains to be elucidated. In patients who require surgery, careful management is needed. We sought to investigate the optimal perioperative management of such patients, including the use of pharmacological and mechanical thromboprophylaxis, possible thrombolytic therapy, and inferior vena cava (IVC) filters. A literature search was conducted, and all relevant articles were identified, investigated, and included. Medical guidelines were also consulted where appropriate. Pharmacological thromboprophylaxis is the mainstay of preoperative treatment, and low-molecular-weight heparins, fondaparinux, and unfractionated heparin may all be used. It has been suggested that prophylaxis should be administered as soon as possible after trauma. Such agents may be contraindicated in patients with significant bleeding, and mechanical prophylaxis and inferior vena cava filters may be favoured in these patients. Therapeutic anticoagulation and thrombolytic therapies may be considered but are associated with an increased risk of haemorrhage. Delaying surgery might help to minimise the risk of recurrent venous thromboembolism, and any interruption of prophylaxis must be strategically planned. Recommendations for postoperative care include a continuation of prophylaxis and therapeutic anticoagulation, with follow-up clinical evaluation within six months. Incidental PE is a common finding on trauma CT scans. Although the clinical significance is unknown, careful management of the balance between anticoagulation and bleeding is needed, especially in trauma patients and even more so in trauma patients requiring surgery.

Prophylactic inferior vena cava filters for operative pelvic fractures: a twelve year experience

INTRODUCTION

Conflicting evidence exists regarding the role of inferior vena cava filters (IVCFs) in the prevention of pulmonary embolism. The aim of this study was to review an institutional policy of prophylactic IVCF placement in all operative pelvic and acetabular fractures as a means of preventing PE by comparing it to a historical prepolicy period of significantly less aggressive IVCF placement.

METHODS

The trauma registry of a single level 1 trauma center was retrospectively queried for all pelvic or acetabular fractures for the prepolicy and intervention periods as defined as January 2003-December 2008 and January 2009-December 2014, respectively-yielding 231 patients for analysis. The primary and secondary outcomes measured were the incidence of PE and deep vein thrombosis.

RESULTS

The rate of prophylactic IVCF insertion significantly increased during the study period (p < 0.001). The incidence of pulmonary embolism (1.8% vs. 5.1%, p = 0.351) and DVT (19.3% vs. 10.3%, p = 0.231) were not significantly different when comparing the prepolicy and intervention cohorts. In patients with operative fractures, a nonsignificant trend of increasing incidence of DVTs was appreciated in patients with a prophylactic IVCF versus those without prophylactic IVCF (13 vs. 2, p = 0.222).

DISCUSSION

A policy of increased use of prophylactic IVCFs in patients with operative pelvic and acetabular fractures failed to reduce the incidence of PE or DVT. In contrast, several case reports and institutional series have published several risks associated with IVCF placement including failure to retrieve temporary IVCF.

CONCLUSION

The benefit of prophylactic IVCF in this patient population is unclear.

Prevention of Deep Venous Thromboembolism

The nature of many combat wounds puts patients at a high risk of developing deep venous thrombosis (DVT) and pulmonary embolism (PE), which fall under the broader disease category of venous thromboembolism (VTE). In addition to the hypercoagulable state induced by trauma, massive injuries to the extremities, prolonged immobility, and long fixed wing transport times to higher echelons of care are unique risk factors for venous thromboembolism in the combat-injured patient. These risk factors mandate aggressive prophylaxis for DVT and PE that can effectively be achieved by the use of lower extremity sequential compression devices and low dose unfractionated heparin or low molecular weight heparin. In addition, inferior vena cava filters are often used for PE prophylaxis when chemical DVT prophylaxis fails or is contraindicated. The following Department of Defense (DoD) Joint Trauma System (JTS) Clinical Practice Guideline (CPG) discusses the current recommendations for the prevention of DVT and PE including the use of inferior vena cava filters (IVCFs).

A Systematic Review of the Risks and Benefits of Venous Thromboembolism Prophylaxis in Traumatic Brain Injury

BACKGROUND

Patients suffering from traumatic brain injury (TBI) are at increased risk of venous thromboembolism (VTE). However, initiation of pharmacological venous thromboprophylaxis (VTEp) may cause further intracranial hemorrhage. We reviewed the literature to determine the postinjury time interval at which VTEp can be administered without risk of TBI evolution and hematoma expansion.

METHODS

MEDLINE and EMBASE databases were searched. Inclusion criteria were studies investigating timing and safety of VTEp in TBI patients not previously on oral anticoagulation. Two investigators extracted data and graded the papers' levels of evidence. Randomized controlled trials were assessed for bias according to the Cochrane Collaboration Tool and Cohort studies were evaluated for bias using the Newcastle-Ottawa Scale. We performed univariate meta-regression analysis in an attempt to identify a relationship between VTEp timing and hemorrhagic progression and assess study heterogeneity using an I 2 statistic.

RESULTS

Twenty-one studies were included in the systematic review. Eighteen total studies demonstrated that VTEp postinjury in patients with stable head computed tomography scan does not lead to TBI progression. Fourteen studies demonstrated that VTEp administration 24 to 72 hours postinjury is safe in patients with stable injury. Four studies suggested that administering VTEp within 24 hours of injury in patients with stable TBI does not lead to progressive intracranial hemorrhage. Overall, meta-regression analysis demonstrated that there was no relationship between rate of hemorrhagic progression and VTEp timing.

CONCLUSIONS

Literature suggests that administering VTEp 24 to 48 hours postinjury may be safe for patients with low-hemorrhagic-risk TBIs and stable injury on repeat imaging.

Inferior vena cava filter use and patient safety: legacy or science?

There has been a dramatic increase in vena cava filter (VCF) use over the past 20 years in the absence of evidence that filters provide a net patient benefit or are required in most cases. This increase is largely attributable to the availability of retrievable filters and expanded indications, particularly as primary prophylaxis in patients thought to be at high risk of pulmonary embolism. Substantial variability in VCF use, unrelated to patient clinical factors, has been shown between hospitals, from region to region, and among various countries. Despite the lack of direct evidence for the benefit of VCFs for any indication, it is appropriate to insert a retrievable VCF in patients with a recent proximal deep vein thrombosis and an absolute contraindication to therapeutic anticoagulation and then to remove the filter once the bleeding risk decreases and the patient has been anticoagulated. Unfortunately, a high proportion of retrievable filters are not removed, even after the reason for their placement has long passed. Retrievable filters are associated with substantial rates of complications if they are not removed, including penetration of the vena caval wall, fracture and embolization of filter fragments, and caval occlusion. Patient safety priorities and medical-legal concerns mandate careful selection of patients for VCF placement and removal shortly after anticoagulation has been initiated.

Detailed assessment of benefits and risks of retrievable inferior vena cava filters on patients with complicated injuries: the da Vinci multicentre randomised controlled trial study protocol

INTRODUCTION

Retrievable inferior vena cava (IVC) filters have been increasingly used in patients with major trauma who have contraindications to anticoagulant prophylaxis as a primary prophylactic measure against venous thromboembolism (VTE). The benefits, risks and cost-effectiveness of such strategy are uncertain.

METHODS AND ANALYSIS

Patients with major trauma, defined by an estimated Injury Severity Score >15, who have contraindications to anticoagulant VTE prophylaxis within 72 hours of hospitalisation to the study centre will be eligible for this randomised multicentre controlled trial. After obtaining consent from patients, or the persons responsible for the patients, study patients are randomly allocated to either control or IVC filter, within 72 hours of trauma admission, in a 1:1 ratio by permuted blocks stratified by study centre. The primary outcomes are (1) the composite endpoint of (A) pulmonary embolism (PE) as demonstrated by CT pulmonary angiography, high probability ventilation/perfusion scan, transoesophageal echocardiography (by showing clots within pulmonary arterial trunk), pulmonary angiography or postmortem examination during the same hospitalisation or 90-day after trauma whichever is earlier and (B) hospital mortality; and (2) the total cost of treatment including the costs of an IVC filter, total number of CT and ultrasound scans required, length of intensive care unit and hospital stay, procedures and drugs required to treat PE or complications related to the IVC filters. The study started in June 2015 and the final enrolment target is 240 patients. No interim analysis is planned; incidence of fatal PE is used as safety stopping rule for the trial.

ETHICS AND DISSEMINATION

Ethics approval was obtained in all four participating centres in Australia. Results of the main trial and each of the secondary endpoints will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ACTRN12614000963628; Pre-results.

The high-risk polytrauma patient and inferior vena cava filter use

OBJECTIVES

The aim of this study was to assess the impact on practice of vena cava filter insertion guidelines (Eastern Association for the Surgery of Trauma: practice management guidelines).

DESIGN

The study was performed at a level 1 trauma centre with data from the 'Trauma Audit and Research Network' cross-referenced to hospital data.

RESULTS

A total of 1138 specific 'high-risk' major trauma patients were identified over a 6-year period. The mean age was 46 years (18-102) and the male to female ratio was 3.3:1. The average Injury Severity Score was 23.6 (4-75). The overall DVT rate was 2.6% and the PE rate was 1.8%. A retrievable IVC filter was inserted in 42 cases (3.8%). The filter retrieval rate was 23.8% at a mean of 68.5days (4-107). Only one complication was reported of a breakthrough PE despite filter. Applying the EAST guidelines to this cohort would have suggested filter insertion in 279 (24.6%) cases. The kappa concordance value between observed practice and the 'EAST filter group' was 0.103 (poor). The PE rate in the 'EAST filter group' was 2.2% vs 1.6% in the 'no filter group' (p=0.601, no statistical difference) and the observed odds ratio was 0.814 (95% CI 0.413, 1.602).

CONCLUSION

The EAST guidelines are useful but may be overestimating the need for filter insertion.

The Parkland Protocol's modified Berne-Norwood criteria predict two tiers of risk for traumatic brain injury progression

As a basis for venous thromboembolism (VTE) prophylaxis after traumatic brain injury (TBI), we have previously published an algorithm known as the Parkland Protocol. Patients are classified by risk for spontaneous progression of hemorrhage with chemoprophylaxis regimens tailored to each tier. We sought to validate this schema. In our algorithm, patients with any of the following are classified "low risk" for spontaneous progression: subdural hemorrhage ≤8 mm thick; epidural hemorrhage ≤8 mm thick; contusions ≤20 mm in diameter; a single contusion per lobe; any amount of subarachnoid hemorrhage; or any amount of intraventricular hemorrhage. Patients with any injury exceeding these are "moderate risk" for progression, and any patient receiving a monitor or craniotomy is "high risk." From February 2010 to November 2012, TBI patients were entered into a dedicated database tracking injury types and sizes, risk category at presentation, and progression on subsequent computed tomgraphies (CTs). The cohort (n=414) was classified as low risk (n=200), moderate risk (n=75), or high risk (n=139) after first CT. After repeat CT scan, radiographic progression was noted in 27% of low-risk, 53% of moderate-risk, and 58% of high-risk subjects. Omnibus analysis of variance test for differences in progression rates was highly significant (p<0.0001). Tukey's post-hoc test showed the low-risk progression rate to be significantly different than both the moderate- and high-risk arms; no difference was noted between the moderate- and high-risk arms themselves. These criteria are a valid tool for classifying TBI patients into two categories of risk for spontaneous progression. This supports tailored chemoprophylaxis regimens for each arm.

Inferior vena cava filters for primary prophylaxis: when are they indicated?

Over the past several years there has been a rapid increase in the number of inferior vena cava (IVC) filters placed for primary thromboprophylaxis. Increased use has occurred in settings where other methods of thromboprophylaxis are viewed to be inadequate, technically challenging, or that place patients at an unacceptably high bleeding risk. These clinical services include trauma, bariatric surgery, neurosurgery, cancer, intensive care unit populations, and patients with a relative contraindication to anticoagulation. We review the studies to date addressing filter placement for these indications. Although preliminary data are promising, the patient populations most likely to benefit from prophylactic IVC filter placement have not been well defined, and randomized studies demonstrating efficacy have not been conducted. Moving forward, it will be critical to accomplish these two tasks if IVC filters are to continue to have a role in primary thromboprophylaxis.

Pulmonary emboli after blunt trauma: timing, clinical characteristics and natural history

BACKGROUND

Venous thromboembolism (VTE) frequently complicates the recovery of trauma patients, and contributes to morbidity and mortality. Recent studies showed an increase in diagnosis of pulmonary embolism (PE) mainly in the early or immediate period after trauma. The clinical significance of those incidental PEs is unclear.

METHODS

The study cohort included all blunt trauma patients who had a contrast-enhanced CT of the chest performed as part of their initial trauma assessment from January 1, 2005 to January 31, 2007 in a large academic Canadian trauma centre. Patients diagnosed with PE at any point during admission were identified using our institutional trauma registry. All chest CT scans and electronic charts were reviewed. Patients were classified according to time of PE detection (immediate, early or late) and symptoms (asymptomatic or symptomatic). The clinical characteristics and hospital course of the patients who were diagnosed with immediate PE were described.

RESULTS

1259 blunt trauma patients were reviewed. Six patients presented with immediate PE (0.5%); nine patients were found to have early PE (0.7%) and 13 had late PE (1.0%). All six of the patients with immediate PE were classified as asymptomatic. Five of the nine patients with early PE were symptomatic and all 13 patients who developed late PE were symptomatic. Amongst the six patients with immediate PE, five survived 24h hospitalisation. Four of them were managed with prophylactic low molecular weight heparin and no other thromboembolic events were observed during admission or after discharge.

CONCLUSIONS

The increased use of advanced CT technology in trauma patients has resulted in an increased diagnosis of incidental PEs that are asymptomatic. The clinical significance and management of these small, incidental PE are uncertain and further studies are needed to clarify the natural history of this controversial finding.

The use of prophylactic inferior vena cava filters in trauma patients: a systematic review

INTRODUCTION

Pulmonary embolisms (PE) are an often preventable cause of late morbidity and mortality after trauma. Although there is evidence for the use of therapeutic inferior vena cava (IVC) filters (defined as IVC filters implanted in those with proven deep venous thrombosis [DVT] in order to prevent PE), there is not as much evidence to support the use of prophylactic IVC filters. Thus, we undertook a systematic review of the literature to assess the following in prophylactic IVC filters: efficacy in PE reduction, prevalence of filter-related complications and the indications for use.

MATERIALS AND METHODS

After screening 249 studies, 24 studies met inclusion criteria for qualitative synthesis.

RESULTS

Overall, the literature is supportive of the use of prophylactic IVC filters in high-risk poly-trauma patients who may have contraindications to DVT prophylaxis. Filter-associated complications are uncommon and, when they do occur, tend to be of limited clinical significance. Limited data, mostly in the form of case series, supports a reduction in PE and PE-related mortality. There has been increasing use of retrievable filters as well as the ability to safely retrieve them at longer intervals.

CONCLUSION

Despite the addition of a few matched-control studies, the literature is still plagued by a lack of high quality data, and therefore the true efficacy of prophylactic IVC filters for prevention of PE in trauma patients remains unclear. Further studies are required to determine the true role of prophylactic IVC filters in trauma patient.

Filtro de veia cava: uma década de experiência em um centro de trauma nível I

OBJETIVO: Avaliar os dados relativos à utilização de filtro de veia cava na Divisão de Trauma do Centro Médico da UCSD San Diego, CA/EUA. MÉTODOS: Estudo descritivo realizado na Divisão de Trauma visando avaliar a experiência acumulada e a conduta terapêutica nos doentes atendidos pela equipe da Divisão de Trauma e submetidos à colocação de filtro de veia cava como método de prevenção ou tratamento do TEP no período de janeiro de 1999 a dezembro de 2008. RESULTADOS: O estudo compreendeu 512 doentes, destacando-se o sexo masculino (73%). Quanto à causa do traumatismo predominou o acidente automobilístico, seguido por lesões provocadas por quedas. A relação homem/mulher foi 3:1. A faixa etária mais atingida foi 21 a 40 anos, representando 36% dos doentes. O percentual de filtros de cava profiláticos foi de 82% contra 18% de filtros terapêuticos. O traumatismo craniano foi a principal causa para indicação de filtros profiláticos seguido dos traumas raquimedulares. O índice de TVP pós-filtro foi 11%. CONCLUSÃO: Na presença de contraindicação ao uso de anticoagulantes em doentes vítimas de trauma grave, os filtros de veia cava inferior demonstraram ser uma opção efetiva e segura. Entretanto, deve-se aplicar rigor ao julgamento clínico para todas as indicações, mesmo após o advento de filtros "recuperáveis".

Review of indications and practices of vena caval filters at a large university hospital

BACKGROUND

Vena caval filter (VCF) use has been increasing in recent years. Prophylactic VCF placement has been applied liberally in high-risk patients.

METHODS

Consecutive patients with VCF placement over a 2-year period at a university hospital were reviewed.

RESULTS

A total of 244 patients underwent VCF placement in 2 years. Of all, 54% of the patients had the VCF placed for an absolute indication, 14% for a relative indication, and 32% for prophylaxis. Only 14 (9%) of the retrievable filters were removed. Eight patients had a complication of VCF placement; there were no complications of filter retrieval. Vena caval filter placement for prophylaxis alone was 57% from the division of trauma and surgical critical care, 18.3% from interventional radiology department, and 5.2% from the division of vascular surgery.

CONCLUSIONS

This study indicates that many VCFs are placed for prophylaxis. A low percentage of VCFs was retrieved. This may be the practice at many other large university-based hospitals, necessitating strategies for reducing their placement.

A method for following patients with retrievable inferior vena cava filters: results and lessons learned from the first 1,100 patients

PURPOSE

Patients who have undergone implantation of a retrievable inferior vena cava (IVC) filter require continued follow-up to have the device removed when clinically appropriate and in a timely fashion to avoid potential long-term filter-related complications. The efficacy of a method for patient follow-up was evaluated based on a retrospective review of a single-institutional retrievable IVC filter experience.

MATERIALS AND METHODS

Patients with retrievable IVC filters were tracked via a prospectively collected database designed specifically for patient follow-up. Follow-up consisted of periodic review of the electronic medical record. Patients were contacted by mail (at regular intervals one or more times) when removal of the filter was deemed appropriate. A retrospective review of the ultimate fate of the first 1,127 retrievable IVC filters placed at a single institution was performed. Retrieval rates were compared with those seen in the initial experience, during which no structured follow-up was performed.

RESULTS

Of 1,127 filters placed, 658 (58.4%) were removed. Filter removal or declaration of the device as permanent was achieved in 860 patients (76.3%). Filter removal, declaration of the device as permanent, or establishment of the need for continued follow-up was achieved in 941 patients (83.5%). Only 186 patients (16.5%) were lost to follow-up.

CONCLUSIONS

The follow-up method described in the present study resulted in a statistically significant difference (P < .001) in the likelihood of a patient returning for IVC filter removal compared with a lack of follow-up (59% vs 24%).

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.

Retrievable inferior vena cava filters are not getting retrieved: where is the gap?

OBJECTIVE

The purpose of this study is to assess the retrieval rate and the predictors of successful retrieval of Retrievable Inferior Vena Cava (RIVC) filters.

METHODS

We retrospectively reviewed the medical records of adult patients who had RIVC filter placements from 2004-2008. We excluded patients who died or were lost to follow-up and those who refused or had unsuccessful retrieval. We collected demographic and clinical data including indications for placement and follow-up. Successful retrieval was defined as objective evidence of retrieval by medical records.

RESULTS

Over a 4 year period, we identified 351 patients who had RIVC filter placements. We excluded 99 patients (65 died, 24 decided to leave filter in place, 7 had unsuccessful retrieval and 3 lost follow-up). Majority of the filters were placed for surgical patients (161, 63.9%). Of 252 eligible patients for retrieval, only 47 filters were successfully retrieved yielding a retrieval rate of 18.7%. We identified three predictors for successful retrieval: Male gender, home discharge and follow up with procedural service.

CONCLUSION

In this large cohort we found that the retrieval rate of retrievable IVCF is extremely low consistent with national statistics. Male patients, patients who were discharged home and patients who were followed by the procedural service had higher chance of successful retrieval. We recommend that procedural service placing the filter should ascertain adequate follow-up. We are not certain why more males had successful retrieval than females. Further studies are necessary to investigate this finding.

Deep vein thrombosis prophylaxis in trauma patients

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are known collectively as venous thromboembolism (VTE). Venous thromboembolic events are common and potentially life-threatening complications following trauma with an incidence of 5 to 63%. DVT prophylaxis is essential in the management of trauma patients. Currently, the optimal VTE prophylaxis strategy for trauma patients is unknown. Traditionally, pelvic and lower extremity fractures, head injury, and prolonged immobilization have been considered risk factors for VTE; however it is unclear which combination of risk factors defines a high-risk group. Modalities available for trauma patient thromboprophylaxis are classified into pharmacologic anticoagulation, mechanical prophylaxis, and inferior vena cava (IVC) filters. The available pharmacologic agents include low-dose heparin (LDH), low molecular weight heparin (LMWH), and factor Xa inhibitors. Mechanical prophylaxis methods include graduated compression stockings (GCSs), pneumatic compression devices (PCDs), and A-V foot pumps. IVCs are traditionally used in high risk patients in whom pharmacological prophylaxis is contraindicated. Both EAST and ACCP guidelines recommend primary use of LMWHs in trauma patients; however there are still controversies regarding the definitive VTE prophylaxis in trauma patients. Large randomized prospective clinical studies would be required to provide level I evidence to define the optimal VTE prophylaxis in trauma patients.

Incidence and risk factors for fatal pulmonary embolism after major trauma: a nested cohort study

BACKGROUND

Venous thromboembolism is common after major trauma. Strategies to prevent fatal pulmonary embolism (PE) are widely utilized, but the incidence and risk factors for fatal PE are poorly understood.

METHODS

Using linked data from the intensive care unit, trauma registry, Western Australian Death Registry, and post-mortem reports, the incidence and risk factors for fatal PE in a consecutive cohort of major trauma patients, admitted between 1994 and 2002, were assessed. Non-linear relationships between continuous predictors and risk of fatal PE were modelled by logistic regression.

RESULTS

Of the 971 consecutive trauma patients considered in the study, 134 (13.8%) died after their injuries. Fatal PE accounted for 11.9% of all deaths despite unfractionated heparin prophylaxis being used in 44% of these patients. Fatal PE occurred in those who were older (mean age 51- vs 37-yr-old, P=0.01), with more co-morbidities (Charlson's co-morbidity index 1.1 vs 0.2, P=0.01), had a larger BMI (31.8 vs 24.5, P=0.01), and less severe head and systemic injuries when compared with those who died of other causes. Sites of injuries were not significantly related to the risk of fatal PE. Fatal PE occurred much later than deaths from other causes (median 18 vs 2 days, P=0.01), and the estimated attributable mortality of PE was 49% (95% confidence interval 36-62%).

CONCLUSIONS

Fatal PE appeared to be a potential preventable cause of late mortality after major trauma. Severity of injuries, co-morbidity, and BMI were important risk factors for fatal PE after major trauma.

[Vena cava filters in trauma patients]

BACKGROUND

The introduction of removable inferior vena cava filters (IVCF) has created new options for the prevention of pulmonary embolisms in surgical trauma patients. We have observed increasing use in trauma patients.

PATIENTS AND METHODS

A retrospective analysis was carried out of 49 trauma patients out of 85 who received IVCFs at our level 1 trauma centre in 2008.

RESULTS

The indications for IVCF placement were multiple trauma in 33 patients, severe head injury in 13 and spinal injury in 3 patients. Of the patients 34 underwent successful removal, 11 (22%) patients had had no retrieval attempt by December 2009 and attempts at removal were unsuccessful in 3 patients. The mean age of the patients was 33.3 years.

CONCLUSION

In 2008 the vast majority of IVCFs were inserted for prophylaxis in trauma patients. To increase the number of retrieved IVCFs, responsibility for the removal should be clarified in every hospital. The indications, advantages, safety and also the design of IVCFs are still under debate. A randomized controlled trial is needed to determine the appropriate use and indications for this potentially useful device in trauma patients.

An economic evaluation of venous thromboembolism prophylaxis strategies in critically ill trauma patients at risk of bleeding

BACKGROUND

Critically ill trauma patients with severe injuries are at high risk for venous thromboembolism (VTE) and bleeding simultaneously. Currently, the optimal VTE prophylaxis strategy is unknown for trauma patients with a contraindication to pharmacological prophylaxis because of a risk of bleeding.

METHODS AND FINDINGS

Using decision analysis, we estimated the cost effectiveness of three VTE prophylaxis strategies-pneumatic compression devices (PCDs) and expectant management alone, serial Doppler ultrasound (SDU) screening, and prophylactic insertion of a vena cava filter (VCF) -- in trauma patients admitted to an intensive care unit (ICU) with severe injuries who were believed to have a contraindication to pharmacological prophylaxis for up to two weeks because of a risk of major bleeding. Data on the probability of deep vein thrombosis (DVT) and pulmonary embolism (PE), and on the effectiveness of the prophylactic strategies, were taken from observational and randomized controlled studies. The probabilities of in-hospital death, ICU and hospital discharge rates, and resource use were taken from a population-based cohort of trauma patients with severe injuries (injury severity scores >12) admitted to the ICU of a regional trauma centre. The incidence of DVT at 12 weeks was similar for the PCD (14.9%) and SDU (15.0%) strategies, but higher for the VCF (25.7%) strategy. Conversely, the incidence of PE at 12 weeks was highest in the PCD strategy (2.9%), followed by the SDU (1.5%) and VCF (0.3%) strategies. Expected mortality and quality-adjusted life years were nearly identical for all three management strategies. Expected health care costs at 12 weeks were Can$55,831 for the PCD strategy, Can$55,334 for the SDU screening strategy, and Can$57,377 for the VCF strategy, with similar trends noted over a lifetime analysis.

CONCLUSIONS

The attributable mortality due to PE in trauma patients with severe injuries is low relative to other causes of mortality. Prophylactic placement of VCF in patients at high risk of VTE who cannot receive pharmacological prophylaxis is expensive and associated with an increased risk of DVT. Compared to the other strategies, SDU screening was associated with better clinical outcomes and lower costs.