Venous thromboembolism in the intensive care unit: the last frontier for prophylaxis

Patients with severe accidental tetanus admitted to an intensive care unit in Northeastern Brazil: clinical-epidemiological profile and risk factors for mortality

Introduction

Tetanus, an acute infectious disease, is highly prevalent worldwide, especially in developing countries. Due to respiratory failure and hemodynamic instability associated with dysautonomia, severe cases require intensive care, but little has been published regarding the management in the Intensive Care Unit.

Objective

To draw a 10-year clinical–epidemiological profile of Intensive Care Unit patients with severe tetanus, observe their evolution in the Intensive Care Unit and identify risk factors for mortality.

Methods

In this retrospective study, we used a standardized questionnaire to collect information from the records of patients with severe tetanus admitted to the intensive care unit of a referral hospital for infectious and contagious diseases in Northeastern Brazil.

Results

The initial sample included 144 patients, of whom 29 were excluded due to incomplete information, leaving a cohort of 115 subjects. The average age was 49.6 ± 15.3 years, most patients had no (or incomplete) vaccination against tetanus, and most were male. The main intensive care-related complications were pneumonia (84.8%) and dysautonomia (69.7%). Mortality (44.5%) was higher than expected from the mean APACHE II score (11.8), with shock/multiple organ failure as the main cause of death (72.9%). The independent factors most predictive of mortality were APACHE II score, dysautonomia, continuous neuromuscular blockade and age.

Conclusion

A high mortality rate was observed in our cohort of Intensive Care Unit patients with severe tetanus and a number of risk factors for mortality were identified. Our results provide important insights for the development of intervention protocols capable of reducing complications and mortality in this patient population.

Angel® Catheter — A Solution to Pulmonary Embolism Prophylaxis in the Critically Ill Patient

Pulmonary embolism (PE) is a serious complication among critically ill patients. Despite the recommended and effective use of prophylactic anticoagulation, new options are required, particularly for critically ill patients with absolute or temporary contraindications to the use of anticoagulation. The Angel® Catheter (BiO2 Medical, Inc. San Antonio, Texas) is intended for these critically ill patients, allowing early PE prophylaxis without additional bleeding risk. The device is inserted at the bedside, provides both central venous access and inferior vena cava filtration, and can be successfully removed in all instances. Clinical experience and ongoing research will help define the role of the Angel Catheter in PE prophylaxis for critically ill patients.

A new device for the prevention of pulmonary embolism in critically ill patients: Results of the European Angel Catheter Registry

BACKGROUND

Pulmonary embolism (PE) is a potentially life-threatening complication of critical illness. In trauma and neurosurgical patients with contraindications to anticoagulation, inferior vena cava (IVC) filters have been used to prevent PE, but their associated long-term complication rates and difficulties associated with filter removal have limited their use. The Angel catheter is a temporary device, which combined an IVC filter with a triple-lumen central venous catheter (IVC filter-catheter) and is intended for bedside placement and removal when no longer indicated.

METHODS

This study presents data from a European Registry of 60 critically ill patients in whom the IVC filter-catheter was used to prevent PE. The patients were all at high risk of PE development or recurrence and had contraindications to anticoagulation. The primary end points of this study were to evaluate the safety (in particular, the presence of infectious or thrombotic events) and effectiveness (the numbers of PEs and averted PEs) of the IVC filter-catheter.

RESULTS

The main diagnosis before catheter insertion was major trauma in 33 patients (55%), intracerebral hemorrhage or stroke in 9 (15%), a venous thromboembolic event in 9 (15%), and active bleeding in 6 (10%). The IVC filter-catheter was placed as prophylaxis in 51 patients (85%) and as treatment in the 9 patients (15%) with venous thromboembolic event. The devices were inserted at the bedside without fluoroscopic guidance in 54 patients (90%) and within a median of 4 days after hospital admission. They were left in place for a mean of 6 days (4-8 days). One patient developed a PE, without hemodynamic compromise; two PEs were averted. No serious adverse events were reported.

CONCLUSION

Early bedside placement of an IVC filter-catheter is possible, and our results suggest that this is a safe, effective alternative to short-term PE prophylaxis for high-risk patients with contraindications to anticoagulation.

LEVEL OF EVIDENCE

Therapeutic study, level V.

PROphylaxis for ThromboEmbolism in Critical Care Trial protocol and analysis plan

BACKGROUND

This article reports the preparatory studies as well as the design, implementation, and a priori analysis plans of PROphylaxis for ThromboEmbolism in Critical Care Trial (PROTECT) before dissemination of results. PROphylaxis for ThromboEmbolism in Critical Care Trial (NCT00182143) is a randomized, stratified, concealed international trial comparing subcutaneous injection of unfractionated heparin (UFH) 5000 IU or the low-molecular weight heparin (LMWH) dalteparin 5000 IU once daily plus once-daily placebo for the duration of the intensive care unit stay.

METHODS

The objective of PROTECT is to examine, among medical-surgical critically ill patients, the effect of the LMWH vs heparin on the primary outcome of proximal leg deep vein thrombosis (DVT) and the following secondary outcomes: DVT elsewhere, pulmonary embolism, any venous thromboembolism (DVT or pulmonary embolism), the composite of venous thromboembolism or death, bleeding, and heparin-induced thrombocytopenia. Patients are followed up to death or hospital discharge. Venous thromboembolism events were included after intensive care unit discharge. All patients, families, clinicians, research personnel, and the trial biostatistician are blind to allocation.

RESULTS

We describe the pilot work, large trial methodology, implementation methods, and the analytic plan. Patient recruitment is complete, but 2 patients remain in the hospital. The rigorous design of PROTECT suggests that the risk of systematic error will be low. The sample size suggests that the risk of random error will be low. PROTECT will be the largest investigator-initiated peer-review funded thromboprophylaxis trial in critical care in the world.

CONCLUSIONS

If PROTECT shows that LMWH is more effective than UFH, this trial will change practice in that LMWH may be the anticoagulant thromboprophylaxis of choice for this population. If the results show that UFH is as effective or more effective than LMWH, intensivists in many parts of the world may continue to use UFH, whereas those currently using LMWH may reconsider and change to use UFH. Unfavorable consequences such as major bleeding, ease of use, and the costs of complications will also factor into such decisions.

Thromboprophylaxis in the intensive care unit: focus on medical-surgical patients

Critically ill patients in the medical-surgical intensive care unit are at high risk for deep venous thrombosis and pulmonary embolism, which comprise venous thromboembolism. Herein, we describe the prevalence, incidence, risk factors, clinical consequences, prophylaxis against venous thromboembolism in critically ill patients, and compliance with thromboprophylaxis. We focus primarily on medical-surgical intensive care unit patients, who represent the largest subgroup of critically ill patients. Despite the large and growing number of critically ill patients in our aging society, their high risk for venous thromboembolism, and the morbidity and mortality associated with this complication of critical illness, relatively few rigorous studies are available. Large, well-designed, randomized trials of thromboprophylaxis, powered to detect differences in patient-important outcomes, are required to advance our understanding and care of these vulnerable patients. Furthermore, because thromboprophylaxis is a common error of omission in hospitalized patients, redoubled efforts are needed to ensure that it is used in practice.

A survey of thromboprophylaxis management in patients with major trauma

BACKGROUND

Venous thromboembolism (VTE) is a common life-threatening complication of major trauma. Although clinical guidelines clearly suggest routine VTE prevention with low-molecular-weight heparin (LMWH) in this specific group of patients, there is still a lack of strong recommendations regarding the timing and the modality of heparin administration and the role of mechanical prophylaxis. We tested the hypothesis that there is significant practice variation in thromboprophylaxis management of patients with major trauma among intensive care unit (ICU) specialists.

METHODS

Two hundred Italian ICU specialists, representing 200 ICU throughout the country, were contacted by telephone and were asked (1) whether they routinely prescribe pharmacological antithrombotic prophylaxis in patients with major trauma, whether prophylaxis is prescribed to all patients or to selected patients, and the type of prophylaxis and the timing of administration and (2) whether they recommend physical prevention, whether this is prescribed to all patients or to selected patients, and the type of physical prophylaxis.

RESULTS

In patients with major trauma, 85% of the interviewed ICU specialists answered that they prescribe pharmacological prophylaxis for VTE. 37.6% of them prescribe prophylaxis only to selected patients based on the level of risk, 87.7% prescribe low-molecular-weight heparin, and 42.4% start prophylaxis immediately after hospitalization. Only 61% of the interviewed specialists prescribe physical prophylaxis; 82.8% of them use elastic stockings, 9.8% intermittent pneumatic compression, and 7.4% other mechanical devices. Physical prophylaxis is prescribed to all patients by 41%, and by 59% only in case of contraindication to pharmacological prevention. Inferior vena cava (IVC) filter insertion is considered by 47% when anticoagulation is contraindicated; 91.4% of them recommend the IVC filter only if deep vein thrombosis (DVT) has been diagnosed.

CONCLUSIONS

Even when there are clinical guidelines, prescription of VTE prevention in patients with major trauma is underused and timing and modality of prophylaxis are rather heterogeneous. When anticoagulation is contraindicated, IVC filters are commonly recommended only in the presence of DVT.

Minimizing errors of omission: Behavioural rEenforcement of Heparin to Avert Venous Emboli: The BEHAVE Study*

OBJECTIVE

To improve patient safety by increasing heparin thromboprophylaxis for medical-surgical intensive care unit patients using a multiple-method approach to evidence-based guideline development and implementation.

DESIGN

Prospective longitudinal observational study.

SETTING

Medical-surgical intensive care unit.

PARTICIPANTS

Multidisciplinary clinicians caring for critically ill patients in a 15-bed medical-surgical closed intensive care unit.

INTERVENTIONS

Phase 1 was a 3-month baseline period during which we documented anticoagulation and mechanical thromboprophylaxis. Phase 2 was a 1-yr period in which we implemented a thromboprophylaxis guideline using a) interactive multidisciplinary educational in-services; b) verbal reminders to the intensive care unit team; c) computerized daily nurse recording of thromboprophylaxis; d) weekly graphic feedback to individual intensivists on guideline adherence; and e) publicly displayed graphic feedback on group performance. Phase 3 was a 3-month follow-up period 10 months later, during which we documented thromboprophylaxis. Computerized daily nurse recording of thromboprophylaxis continued in this period.

MEASUREMENTS AND MAIN RESULTS

Intensive care unit and hospital mortality rates were similar across phases, although patients in phase 2 had higher Acute Physiology and Chronic Health Evaluation II scores than patients in phases 1 and 3. The proportion (median % [interquartile range]) of intensive care unit patient-days of heparin thromboprophylaxis in phases 1, 2, and 3 was 60.0 (0, 100), 90.9 (50, 100), and 100.0 (60, 100), respectively (p=.01). The proportion (median % [interquartile range]) of days during which heparin thromboprophylaxis was omitted in error in phases 1, 2, and 3 was 20 (0, 53.8), 0 (0, 6.3), and 0 (0, 0), respectively (p<.001).

CONCLUSIONS

After development and implementation of an evidence-based thromboprophylaxis guideline, we found significantly more patients receiving heparin thromboprophylaxis. Guideline adherence was maintained 1 yr later. Further research is needed on which are the most effective strategies to implement patient safety initiatives in the intensive care unit.

Deep venous thrombosis in medical-surgical critically ill patients: prevalence, incidence, and risk factors

OBJECTIVE

Critically ill patients may be at high risk of venous thromboembolism. The objective was to determine the prevalence, incidence, and risk factors for proximal lower extremity deep venous thrombosis among critically ill medical-surgical patients.

DESIGN

Prospective cohort.

SETTING

Closed university-affiliated intensive care unit.

PATIENTS

We enrolled consecutive patients > or =18 yrs of age expected to be in intensive care unit for > or =72 hrs. Exclusion criteria were an admitting diagnosis of trauma, orthopedic surgery, pregnancy, and life support withdrawal.

INTERVENTIONS

Interventions included bilateral lower extremity compression ultrasound within 48 hrs of intensive care unit admission, twice weekly, and if venous thromboembolism was clinically suspected. Thromboprophylaxis was protocol directed and universal. We recorded deep venous thrombosis risk factors at baseline and daily, using multivariate regression analysis to determine independent predictors. Patients were followed to hospital discharge.

RESULTS

Among 261 patients with a mean Acute Physiology and Chronic Health Evaluation II score of 25.5 (+/-8.4), the prevalence of deep venous thrombosis was 2.7% (95% confidence interval 1.1-5.5) on intensive care unit admission, and the incidence was 9.6% (95% confidence interval 6.3-13.8) over the intensive care unit stay. We identified four independent risk factors for intensive care unit-acquired deep venous thrombosis: personal or family history of venous thromboembolism (hazard ratio 4.0, 95% confidence interval 1.5-10.3), end-stage renal failure (hazard ratio 3.7, 95% confidence interval 1.2-11.1), platelet transfusion (hazard ratio 3.2, 95% confidence interval 1.2-8.4), and vasopressor use (hazard ratio 2.8, 95% confidence interval 1.1-7.2). Patients with deep venous thrombosis had a longer duration of mechanical ventilation (p = .03), intensive care unit stay (p = .005), and hospitalization (p < .001) than patients without deep venous thrombosis.

CONCLUSIONS

Despite universal thromboprophylaxis, medical-surgical critically ill patients remain at risk for lower extremity deep venous thrombosis. Further research is needed to evaluate the risks and benefits of more intense venous thromboembolism prophylaxis.

Preventing venous thromboembolism in medical patients

Given the increased number of patients hospitalized for acute medical illnesses and the associated risk of venous thromboembolism (VTE), the use of prophylaxis has become a public health matter. Thromboprophylaxis is not widely practiced in acutely ill medical patients, due in part to the heterogeneity of this group and the perceived difficulty in assessing those who would most benefit from treatment. Nevertheless, the results of recent well-conducted clinical trials support the evidence-based recommendations for more widespread systematic use of low-dose low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) in this population. Three large well-controlled studies (MEDENOX, PREVENT, and ARTEMIS) in acutely ill medical patients confirm previous findings that different at-risk patient populations show a consistent 50% reduction in VTE events with LMWH and fondaparinux. A meta-analysis in nearly 5000 patients in internal medicine comparing UFH and LMWH revealed a trend for reduction of deep vein thrombosis and pulmonary embolism with LMWH. Based on duration of use in clinical trials in acutely ill medical patients, prophylactic treatment with UFH and LMWH is recommended for 2 weeks.

Prevention of venous thromboembolism in critically ill medical patients: a Franco-Canadian cross-sectional study

BACKGROUND

Medical intensive care unit (ICU) patients are at moderate risk of venous thromboembolism (VTE) and prophylaxis against VTE is recommended.

OBJECTIVES

To observe the range and frequency of VTE prophylaxis administered to medical ICU patients and to determine factors associated with different strategies in French and Canadian ICUs.

DESIGN

Prospective cross-sectional observational study.

RESULTS

113/251 (45.0%) French and 29/30 (96.6%) Canadian ICUs agreed to participate. Of 1,222 critically ill medical patients, most were mechanically ventilated (62.5%). Overall, heparin VTE prophylaxis was administered to 63.9% patients, similarly between the 2 countries. Excluding patients with contraindications to heparin and those receiving therapeutic anticoagulation, 91.7% of medical ICU patients appropriately received either low dose unfractionated heparin (UFH) or low molecular weight heparin (LMWH) prophylaxis. Independent predictors of heparin prophylaxis were invasive mechanical ventilation (odds ratio [OR]; 95%CI, 2.4 (1.4-4.3) and obesity (OR 3.1; 1.1-8.8). LMWH was less likely to be prescribed for patients with renal failure (OR 0.1; 0.0009-0.9), or receiving antiembolic stockings (OR 0.4, 0.1-0.9), and much more likely to be prescribed in French ICUs (OR 9.2; 5.0-16.9); however, among patients receiving LMWH, high doses were more likely to be prescribed in Canadian ICUs (OR 8.7; 2.0-37.6). Patients who were pregnant or postpartum (OR 7.7, 1.3-44.3), had neurologic failure (OR 2.1, 1.3-3.4), or were Canadian (OR 3.0, 2.1-4.4) were most likely to receive mechanical VTE prophylaxis (with antiembolic stockings or pneumatic compression devices), whereas those who were already receiving heparin were less likely to receive mechanical prophylaxis (OR 0.5, 0.3-0.7).

CONCLUSIONS

In this binational cross-sectional observational study of medical ICU patients, we found that 92% of eligible patients received either UFH or LWMH for VTE prophylaxis. Differences in prescribing between countries include significantly greater use of LMWH in France, but use of lower doses than in Canada, and greater use of mechanical VTE prophylaxis in Canada. More randomized trials of VTE prophylaxis in critically ill medical patients would better inform practice.

Venous thromboembolism in intensive care patients

Venous thromboembolism frequently complicates the management of patients with severe medical and surgical illnesses. Because the diagnosis of VTE is especially challenging in critically ill patients, the focus of intensivists should be on characterization of risk factors and the appropriate choice of VTE prophylaxis. LDUH or LMHW is the preferred choice for VTE prophylaxis in ICU patients. Mechanical methods of prophylaxis should be reserved for patients with a high risk for bleeding. The effectiveness of mechanical methods and of combined strategies of prevention and the clinically important outcomes of therapy need to be explored further in critically ill patients. Few diagnostic strategies have been assessed in ICU patients with suspected PE. Ventilation-perfusion lung scans remain a pivotal diagnostic test but retain the same limitations in critically ill patients as seen in other patient populations. Newer noninvasive techniques, such as spiral CT associated with imaging of the extremities, are gaining more wide-spread use, but, thus far, pulmonary angiography remains the most reliable technique to confirm or exclude PE in patients with respiratory failure. A consensus must be reached regarding the most appropriate combination of tests for adequate and cost-effective diagnosis of VTE. Further investigation of diagnostic strategies that include adequate consideration of clinical diagnosis using standardized models and noninvasive imaging are warranted.

Differential effects of clivarin and heparin in patients undergoing hip and knee surgery for the generation of anti-heparin-platelet factor 4 antibodies

The pathophysiology of heparin-induced thrombocytopenia (HIT) syndrome is mediated via a heterogeneous group of heparin(s)-platelet factor 4 (H-PF4) complexes bound to their antibodies. These anti-H-PF4 (AHPF4) antibodies that are capable of binding to the FcgammaRIIA receptor [cluster of differentiation (CD) 32] on platelets, resulting in platelet activation, widely vary in their specific activities as platelet activation (functionality). Predisposing factors related to specific pathologic conditions may also contribute to the generation of these antibodies and their relative functionality during HIT syndrome. To understand this phenomenon, a sub-study was carried out in patients undergoing elective total hip and knee replacement surgery (ECHOS Study) and who were treated with unfractionated heparin (UFH) and a low-molecular-weight heparin (LMWH; Clivarin). Approximately 600 patients per arm [UFH=7,500 anti-Xa U twice a day (b.i.d.) subcutaneous (s.c.) and clivarin=4200 U once daily (o.d.) s.c.], age >40 years, received prophylactic treatment for a minimum of 11-14 days. Plasma samples were collected at pre-dose, days 2-4, days 11-14 and at follow-up 6-8 weeks after discharge and were analyzed for AHPF4 antibody titers. Functionality of the enzyme-linked immunosorbant assay (ELISA)-positive AHPF4 antibodies to cause platelet activation was tested by 14C-serotonin release assay (SRA). Both UFH and clivarin treatments in orthopedic surgical patients resulted in a progressive generation of AHPF4 antibodies. The relative prevalence/functionality of AHPF4 antibodies in clivarin arm was markedly lower (two- to threefold, p<0.001) as compared to UFH at each time point. Most of the samples in clivarin group were found to be SRA negative, suggesting the presence of AHPF4 antibodies that did not activate platelets (nonfunctional). Within the UFH arm, the relative prevalence/functionality of AHPF4 antibodies was much higher (p<0.002) in knee group compared to the corresponding hip group. This study, for the first time, reports on the elevated levels of AHPF4 antibodies generated by heparin associated with the pathogenesis of knee surgery. Clinical significance of the differential generation of HIT-associated antibodies remains unexplored at this time.

Venous thromboembolism and its prevention in critical care

BACKGROUND

Evidence-based guidelines for the prevention of venous thromboembolism (VTE) are available for most major surgical and medical patient groups. Such guidelines have not been established for critically ill patients.

OBJECTIVE

To perform a systematic review of the prevalence of deep vein thrombosis (DVT), the efficacy of thromboprophylaxis, and the rates of thromboprophylaxis use in critically ill patients.

METHODS

Computerized literature search for relevant studies meeting prespecified criteria.

RESULTS

The rates of objectively confirmed DVT in 4 prospective studies ranged from 13% to 31%. We identified only 3 randomized trials (1 in abstract form) of thromboprophylaxis in critical care unit patients. These studies show the efficacy of low-dose heparin and low molecular weight heparin compared with no prophylaxis; however, we found no trials comparing these 2 interventions. Eleven compliance studies reported that some form of thromboprophylaxis was used in 33% to 100% of critically ill patients, although only 1 study addressed the issue of appropriate prophylaxis use.

CONCLUSIONS

Data on the epidemiology of VTE and its prevention in critically ill patients are very limited. Further research is needed to better define patient risk factors for VTE, optimal methods of thromboprophylaxis, and strategies to improve compliance with prophylaxis recommendations. In the meantime, prevention strategies, shown to be effective in other related patient groups, and general principles of individual pharmacotherapy should guide the routine use of prophylaxis during critical illness.

Prevention and diagnosis of venous thromboembolism in critically ill patients: a Canadian survey

BACKGROUND

Venous thromboembolism (VTE) confers considerable morbidity and mortality in hospitalized patients, although few studies have focused on the critically ill population. The objective of this study was to understand current approaches to the prevention and diagnosis of deep venous thrombosis (DVT) and pulmonary embolism (PE) among patients in the intensive care unit (ICU).

DESIGN

Mailed self-administered survey of ICU Directors in Canadian university affiliated hospitals.

RESULTS

Of 29 ICU Directors approached, 29 (100%) participated, representing 44 ICUs and 681 ICU beds across Canada. VTE prophylaxis is primarily determined by individual ICU clinicians (20/29, 69.0%) or with a hematology consultation for challenging patients (9/29, 31.0%). Decisions are usually made on a case-by-case basis (18/29, 62.1%) rather than by preprinted orders (5/29, 17.2%), institutional policies (6/29, 20.7%) or formal practice guidelines (2/29, 6.9%). Unfractionated heparin is the predominant VTE prophylactic strategy (29/29, 100.0%) whereas low molecular weight heparin is used less often, primarily for trauma and orthopedic patients. Use of pneumatic compression devices and thromboembolic stockings is variable. Systematic screening for DVT with lower limb ultrasound once or twice weekly was reported by some ICU Directors (7/29, 24.1%) for specific populations. Ultrasound is the most common diagnostic test for DVT; the reference standard of venography is rarely used. Spiral computed tomography chest scans and ventilation-perfusion scans are used more often than pulmonary angiograms for the diagnosis of PE. ICU Directors recommend further studies in the critically ill population to determine the test properties and risk:benefit ratio of VTE investigations, and the most cost-effective methods of prophylaxis in medical-surgical ICU patients.

INTERPRETATION

Unfractionated subcutaneous heparin is the predominant VTE prophylaxis strategy for critically ill patients, although low molecular weight heparin is prescribed for trauma and orthopedic patients. DVT is most often diagnosed by lower limb ultrasound; however, several different tests are used to diagnose PE. Fundamental research in critically ill patients is needed to help make practice evidence-based.

Venous thromboembolic disease: an observational study in medical-surgical intensive care unit patients

PURPOSE

Acute and chronic illness, immobility, and procedural and pharmacologic interventions may predispose patients in the intensive care unit (ICU) to venous thromboembolic (VTE) disease. The purpose of this study was to observe potential risk factors and diagnostic tests for VTE, and prophylaxis against VTE in medical-surgical ICU patients.

MATERIALS AND METHODS

In a prospective observational study, 93 consecutive patients admitted to a mixed medical-surgical ICU were followed. We recorded demographics, admitting diagnoses, APACHE II score, VTE risk factors, antithrombotic, anticoagulant and thrombolytic agents, diagnostic tests for deep venous thrombosis (DVT) and pulmonary embolus (PE), and clinical outcomes.

RESULTS

Patients were 65.5 (15.5) years old with an APACHE II score of 21.1 (9.0); 44 (47.3%) were female. Admission diagnoses were medical (58, 67.4%) and surgical (35, 37.6%). The duration of ICU stay was 3 days (interquartile range: 1, 8.5 days) and the ICU mortality rate was 20.4% (19 of 93). We observed 8 VTE events among 5 of 93 patients (incidence 5.4% [0.8 to 10.0]); 2 patients had DVT and PE before admission, 1 had DVT as an admitting diagnosis, 1 had DVT on day 2 and PE on day 3, and 1 had PE on day 2. Over 804 ICU patient-days, 2 of 5 ultrasound examinations diagnosed DVT and 2 of 3 ventilation-perfusion lung scans diagnosed PE. Of 64 patients in whom heparin was not contraindicated and who were not anticoagulated, subcutaneous heparin prophylaxis was prescribed for 40 (62.5%) patients. ICU-acquired VTE risk factors were mechanical ventilation (odds ratio [OR] 1.56), immobility (OR 2.14), femoral venous catheter (OR 2.24), sedatives (OR 1.52), and paralytic drugs (OR 4.81), whereas VTE heparin prophylaxis (OR 0.08), aspirin (OR 0.42), and thromboembolic disease stockings (OR 0.63) were associated with a lower risk. Only warfarin (OR 0.07, P =.01) and intravenous heparin (OR 0.04, P<.01) were associated with a significantly decreased risk of VTE.

CONCLUSIONS

Several ICU-acquired risk factors for VTE were documented in this medical-surgical ICU. VTE prophylaxis was underprescribed, and VTE diagnostic tests were infrequent. Further research is required to determine the incidence, predisposing factors, attributable morbidity, mortality, and costs of VTE in medical-surgical ICU patients, the optimal diagnostic test strategies, and the most cost-effective approaches of prophylaxis.

Novel approaches to the management of disseminated intravascular coagulation

OBJECTIVE

Disseminated intravascular coagulation (DIC) is a syndrome characterized by systemic intravascular activation of coagulation, leading to widespread deposition of fibrin in the circulation. We addressed the issue of whether there is evidence that this fibrin deposition contributes to multiple organ failure. We also explored the current knowledge on the pathogenesis of DIC and reviewed current and future treatment for DIC.

DATA SOURCES

We searched and reviewed published articles on experimental studies of DIC models in animals and clinical studies in patients with DIC.

DATA SYNTHESIS

There is ample experimental and clinical evidence that DIC contributes to morbidity and mortality. Recent knowledge on important pathogenetic mechanisms that may lead to DIC has resulted in novel preventive and therapeutic approaches to patients with DIC. Although the trigger for the activation of the coagulation system may vary depending on the underlying condition, it is usually mediated by several cytokines. Thrombin generation proceeds via the (extrinsic) tissue factor/factor VIIa route and simultaneously occurring depression of inhibitory mechanisms, such as antithrombin III and the protein C-protein S system. Also, impaired fibrin degradation, because of high circulating levels of plasminogen activator inhibitor, type 1, contributes to enhanced intravascular fibrin deposition.

CONCLUSIONS

Although the cornerstone of DIC management is the specific and vigorous treatment of the underlying disorder, strategies aimed at inhibiting coagulation activation may theoretically be justified. Such strategies have been found to be beneficial in experimental and initial clinical studies. These strategies, which follow from our current understanding of the pathophysiology of DIC, involve inhibition of tissue factor-mediated activation of coagulation or restoration of physiologic anticoagulant pathways by means of the administration of antithrombin concentrate or (activated) protein C concentrate. Although no complete evidence from controlled clinical trials is available for most of the proposed therapeutic interventions, these novel strategies are being studied.