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

Modeling current practices in critical care comparative effectiveness research

Objective: To determine whether contemporaneous practices are adequately represented in recent critical care comparative effectiveness research studies. Design: All critical care comparative effectiveness research trials published in the New England Journal of Medicine from April 2019 to March 2020 were identified. To examine studies published in other high impact medical journals during the same period, such trials were subsequently also identified in the Journal of the American Medical Association and The Lancet. All cited sources were reviewed, and the medical literature was searched to find studies describing contemporary practices. Then, the designated control group or the comparable therapies studied were examined to determine if they represented contemporaneous critical care practices as described in the medical literature. Results: Twenty-five of 332 randomised clinical trials published in these three journals during this 1-year period described critical care comparative effectiveness research that met our inclusion criteria. Seventeen characterised current practices before enrolment (using surveys, observational studies and guidelines) and then incorporated current practices into one or more study arm. In the other eight, usual care arms appeared insufficient. Four of these trials randomly assigned patients to one of two fixed approaches at either end of a range of usually titrated care. However, due to randomisation, different subgroups within each arm received care that was inappropriate for their specific clinical conditions. In the other four of these trials, common practices influencing treatment choice were not reflected in the trial design, despite a prior effort to characterise usual care. Conclusion: One-third of critical care comparative effectiveness research trials published in widely read medical journals during a recent year did not include a designated control arm or comparable therapies representative of contemporary practices. Failure to incorporate contemporary practices into critical care comparative effectiveness trials appears to be a widespread design weakness.

Prospective Evaluation of a Rapid Functional Assay for Heparin-Induced Thrombocytopenia Diagnosis in Critically Ill Patients

OBJECTIVES

Overdiagnosis of heparin-induced thrombocytopenia remains an unresolved issue in the ICU leading to the unjustified switch from heparin to alternative anticoagulants or delays in anticoagulation. Platelet function assays significantly improve the specificity of heparin-induced thrombocytopenia diagnosis, but they are not readily available, involve technical difficulties and have a long turnaround time. We evaluated the performance of a rapid and easy to perform functional assay for heparin-induced thrombocytopenia diagnosis in ICU patients, known as "heparin-induced multiple electrode aggregometry."

DESIGN

In this observational prospective study patients were tested with the immunoglobulin G enzyme-linked immunosorbent assay, the serotonin release assay and heparin-induced multiple electrode aggregometry. Heparin-induced multiple electrode aggregometry was assessed against heparin-induced thrombocytopenia diagnosis (clinical picture in favor, serotonin release assay, and immunoglobulin G enzyme-linked immunosorbent assay positive) and serotonin release assay.

SETTING

Medical or surgical ICU of 35 medical centers.

PATIENTS

Patients suspected for heparin-induced thrombocytopenia hospitalized in medical or surgical ICU from January 2013 to May 2013.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Heparin-induced thrombocytopenia diagnosis was retained in 12 patients (14%). Using heparin-induced thrombocytopenia diagnosis as reference, heparin-induced multiple electrode aggregometry showed an excellent negative predictive value and sensitivity, at 98% and 92% respectively. Its positive predictive value and specificity were 100%. Receiver operating characteristic analysis with the serotonin release assay as reference showed an optimal heparin-induced multiple electrode aggregometry cut-off at 1,300 AU × minutes (specificity, 100%; sensitivity, 90%; area under the curve, 0.98; 95% CI, 0.95-1.0). The Kappa coefficient between heparin-induced multiple electrode aggregometry and the serotonin release assay was at 0.90%.

CONCLUSIONS

Heparin-induced multiple electrode aggregometry performed very well in heparin-induced thrombocytopenia diagnosis in ICU patients and agreed with the gold standard test for heparin-induced thrombocytopenia diagnosis, the serotonin release assay. Heparin-induced multiple electrode aggregometry is a reliable and rapid platelet functional assay that could decrease heparin-induced thrombocytopenia overdiagnosis in the ICU setting.

Adjunctive Intermittent Pneumatic Compression for Venous Thromboprophylaxis

BACKGROUND

Whether adjunctive intermittent pneumatic compression in critically ill patients receiving pharmacologic thromboprophylaxis would result in a lower incidence of deep-vein thrombosis than pharmacologic thromboprophylaxis alone is uncertain.

METHODS

We randomly assigned patients who were considered adults according to the local standards at the participating sites (≥14, ≥16, or ≥18 years of age) within 48 hours after admission to an intensive care unit (ICU) to receive either intermittent pneumatic compression for at least 18 hours each day in addition to pharmacologic thromboprophylaxis with unfractionated or low-molecular-weight heparin (pneumatic compression group) or pharmacologic thromboprophylaxis alone (control group). The primary outcome was incident (i.e., new) proximal lower-limb deep-vein thrombosis, as detected on twice-weekly lower-limb ultrasonography after the third calendar day since randomization until ICU discharge, death, attainment of full mobility, or trial day 28, whichever occurred first.

RESULTS

A total of 2003 patients underwent randomization - 991 were assigned to the pneumatic compression group and 1012 to the control group. Intermittent pneumatic compression was applied for a median of 22 hours (interquartile range, 21 to 23) daily for a median of 7 days (interquartile range, 4 to 13). The primary outcome occurred in 37 of 957 patients (3.9%) in the pneumatic compression group and in 41 of 985 patients (4.2%) in the control group (relative risk, 0.93; 95% confidence interval [CI], 0.60 to 1.44; P = 0.74). Venous thromboembolism (pulmonary embolism or any lower-limb deep-vein thrombosis) occurred in 103 of 991 patients (10.4%) in the pneumatic compression group and in 95 of 1012 patients (9.4%) in the control group (relative risk, 1.11; 95% CI, 0.85 to 1.44), and death from any cause at 90 days occurred in 258 of 990 patients (26.1%) and 270 of 1011 patients (26.7%), respectively (relative risk, 0.98; 95% CI, 0.84 to 1.13).

CONCLUSIONS

Among critically ill patients who were receiving pharmacologic thromboprophylaxis, adjunctive intermittent pneumatic compression did not result in a significantly lower incidence of proximal lower-limb deep-vein thrombosis than pharmacologic thromboprophylaxis alone. (Funded by King Abdulaziz City for Science and Technology and King Abdullah International Medical Research Center; PREVENT ClinicalTrials.gov number, NCT02040103; Current Controlled Trials number, ISRCTN44653506.).

Thromboprophylaxis using combined intermittent pneumatic compression and pharmacologic prophylaxis versus pharmacologic prophylaxis alone in critically ill patients: study protocol for a randomized controlled trial

BACKGROUND

Venous thromboembolism (VTE) remains a common problem in critically ill patients. Pharmacologic prophylaxis is currently the standard of care based on high-level evidence from randomized controlled trials. However, limited evidence exists regarding the effectiveness of intermittent pneumatic compression (IPC) devices. The Pneumatic compREssion for preventing VENous Thromboembolism (PREVENT trial) aims to determine whether the adjunct use of IPC with pharmacologic prophylaxis compared to pharmacologic prophylaxis alone in critically ill patients reduces the risk of VTE.

METHODS/DESIGN

The PREVENT trial is a multicenter randomized controlled trial, which will recruit 2000 critically ill patients from over 20 hospitals in three countries. The primary outcome is the incidence of proximal lower extremity deep vein thrombosis (DVT) within 28 days after randomization. Radiologists interpreting the scans are blinded to intervention allocation, whereas the patients and caregivers are unblinded. The trial has 80 % power to detect a 3 % absolute risk reduction in proximal DVT from 7 to 4 %.

DISCUSSION

The first patient was enrolled in July 2014. As of May 2015, a total of 650 patients have been enrolled from 13 centers in Saudi Arabia, Canada and Australia. The first interim analysis is anticipated in July 2016. We expect to complete recruitment by 2018.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT02040103 (registered on 3 November 2013). Current controlled trials: ISRCTN44653506 (registered on 30 October 2013).

Clinical factors associated with inappropriate prophylaxis of venous thromboembolic disease in critically ill patients. A single day cross-sectional study

PURPOSE

A poor implementation of VTE prophylactic measures recommended for critically ill patients has been observed in several epidemiological studies. The clinical factors associated with this have not been clearly established. The objective of our study was to identify which factors could be related to the inappropriate use of VTE prophylaxis.

METHODS

Analytic epidemiological study based on different aspects of VTE prophylaxis performed on Spanish ICU patients. A multiple logistic regression analysis was conducted to identify the risk factors associated with inappropriate prophylaxis, according to the American College of Chest Physicians 2012 guidelines.

RESULTS

We enrolled 777 patients. On admission, 62% presented medical, 30% surgical and 8% major trauma pathology. Of all patients, 41% were receiving an inappropriate prophylaxis, including 19% which did not receive any prophylaxis. The presence of a contraindication for pharmacological prophylaxis (OR 3.91, 95% CI 2.50-6.10) and non-medical pathology at ICU admission (OR 11.09; 95% CI 7.63-16.12) were associated with inappropriate prophylaxis. In contrast, mechanical ventilation (OR 0.70, 95% CI 0.45-0.98), bed rest>48h (OR 0.61, 95% CI 0.49-0.98), the use of a protocol for VTE prophylaxis (OR 0.66, 95% CI 0.45-0.98) and a VTE risk scoring system (OR 0.49, 95% CI 0.24-0.98) were associated with adequate prophylaxis.

CONCLUSIONS

Our study highlighted a poor compliance with the VTE prophylaxis recommendations proposed for critical patients. The implementation of specific protocols for prophylaxis that include a correct evaluation according to VTE and haemorrhage risk, would allow for optimisation of mechanical and combined prophylaxis, improving adherence to the clinical practice guidelines.

Deep Vein Thrombosis in the Lower Extremities in Comatose Elderly Patients with Acute Neurological Diseases

PURPOSE

Comatose elderly patients with acute neurological illness have a great risk of deep vein thrombosis (DVT). In this study, the incidence of DVT and the effectiveness of early initiation of treatment were evaluated in those patients.

MATERIALS AND METHODS

Total 323 patients were admitted to our ward due to neurological diseases in one year, and 43 patients, whose Glasgow Coma Scale was ≤ 11 and who was older than ≥ 60 years, were included in this study. D-dimer was measured on admission and day 7, and lower-extremity ultrasonography was performed on day 7. When DVT was positive, heparin treatment was initiated, and further evaluation of pulmonary embolism (PE) was conducted. Vena cava filter protection was inserted in PE-positive patients. Incidence of DVT and PE, alteration of D-dimer value, and effect of heparin treatment were analyzed.

RESULTS

DVT was positive in 19 (44.2%) patients, and PE was in 4 (9.3%). D-dimer was significantly higher in DVT-positive group on day 7 (p<0.01). No DVT were identified in patients with ischemic disease, while 66.7% of intracerebral hemorrhage and 53.3% of brain contusion patients were DVT positive. Surgery was a definite risk factor for DVT, with an odds ratio of 5.25. DVT and PE disappeared by treatment in all cases, and no patients were succumbed to the thrombosis.

CONCLUSION

Patients with hemorrhagic diseases or who undergo operation possess high risk of DVT, and initiation of heparin treatment in 7 days after admission is an effective prophylaxis for DVT in comatose elderly patients without causing bleeding.

VTE Incidence and Risk Factors in Patients With Severe Sepsis and Septic Shock

BACKGROUND

Prospective studies on the incidence of VTE during severe sepsis and septic shock remain absent, hindering efficacy assessments regarding VTE prevention strategies in sepsis.

METHODS

We prospectively studied 113 consecutively enrolled patients in the ICU with severe sepsis and septic shock at three hospitals. All patients provided informed consent. VTE thromboprophylaxis was recorded for all patients. Patients underwent ultrasonography and were followed for VTE prior to ICU discharge. All-cause 28-day mortality was recorded. Variables from univariate analyses that were associated with VTE (including central venous catheter [CVC] insertion, age, length of stay, and mechanical ventilation) were included in a multivariable logistic regression analysis using backward stepwise elimination to determine VTE predictors.

RESULTS

Mean APACHE (Acute Physiology and Chronic Health Evaluation) II score was 18.2 ± 7.0, and age was 50 ± 18 years. Despite all patients receiving guideline-recommended thromboprophylaxis, the incidence of VTE was 37.2% (95% CI, 28.3-46.8). Most VTE events were clinically significant (defined as pulmonary embolism, proximal DVT, and/or symptomatic distal DVT) and associated with an increased length of stay (18.2 ± 9.9 days vs 13.4 ± 11.5 days, P < .05). Mortality was higher in patients with acute VTE but did not reach statistical significance. Insertion of a CVC and longer mechanical ventilation duration were significant VTE risk factors. VTE incidence did not differ by thromboprophylaxis type.

CONCLUSIONS

To our knowledge this is the first multicenter prospective study to identify a high incidence of VTE in patients with severe sepsis and septic shock, despite the use of universal, guideline-recommended thromboprophylaxis. Our findings suggest that the systemic inflammatory milieu of sepsis may uniquely predispose patients with sepsis to VTE. More effective VTE prevention strategies are necessary in patients with sepsis.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02353910; URL: www.clinicaltrials.gov.

Venous Thromboembolism in Critically Ill Medical Patients Receiving Chemoprophylaxis

Purpose:

To compare the incidence of 90-day venous thromboembolism (VTE) in obese critically ill medical patients receiving VTE chemoprophylaxis with nonobese patients of similar illness severity. We also identified other VTE risk factors.

Methods:

Eligible patients spent ≥24 hours in an intensive care unit between November 2007 and November 2013 and received VTE chemoprophylaxis within 48 hours of admission. The primary outcome was 90-day VTE.

Results:

A total of 11 111 patients were evaluated, of which 1732 obese and 1831 nonobese patients were enrolled with mean BMIs of 38.9 ± 9.2 kg/m2 and 24.5 ± 3.1 kg/m2 and mean Acute Physiology and Chronic Health Evaluation II scores of 28.4 ± 11.8 and 26.6 ± 11.7, respectively. The rate of 90-day VTE for the total cohort, obese, and nonobese patients was 6.5%, 7.5%, and 5.5%, respectively. Obese patients were more likely to develop VTE compared with nonobese patients (odds ratio [OR]: 1.41; 95% confidence interval [CI]: 1.03 -1.93). Other risk factors significantly associated with 90-day VTE included prior VTE (OR: 3.93; 95% CI: 1.83-8.48), trauma with surgery in the previous 30 days (OR: 3.70; 95% CI: 1.39-9.86), central venous catheters (OR: 2.64; 95% CI: 1.87-3.72), surgery within 90 days (OR: 2.40; 95% CI: 1.61-3.58), mechanical ventilation (OR: 1.94; 95% CI: 1.39-2.71), male sex (OR: 1.55; 95% CI: 1.13-2.14), and increasing age using 1-year increments (OR: 1.02; 95% CI: 1.01 -1.03).

Conclusions:

The rate of VTE in critically ill medical patients remains high despite standard chemoprophylaxis. Obesity is among 8 risk factors independently associated with 90-day VTE.

PROF-ETEV study: prophylaxis of venous thromboembolic disease in critical care units in Spain

PURPOSE

Venous thromboembolic disease (VTE) in critically ill patients has a high incidence despite prophylactic measures. This fact could be related to an inappropriate use of these measures due to the absence of specific VTE risk scores. To assess the current situation in Spain, we have performed a cross-sectional study, analyzing if the prophylactic measures were appropriate to the patients' VTE risk.

METHODS

Through an electronic questionnaire, we carried out a single day point prevalence study on the VTE prophylactic measures used in several critical care units in Spain. We performed a risk stratification for VTE in three groups: low, moderate-high, and very high risk. The American College of Chest Physicians guidelines were used to determine if the patients were receiving the recommended prophylaxis.

RESULTS

A total of 777 patients were included; 62% medical, 30% surgical, and 7% major trauma patients. The median number of the risk factors for VTE was four. According to the proposed VTE risk score, only 2% of the patients were at low risk, whereas 83% were at very high risk. Sixty-three percent of patients received pharmacological prophylaxis, 12% mechanical prophylaxis, 6% combined prophylaxis, and 19% did not receive any prophylactic measure. According to criteria suggested by the guidelines, 23% of medical, 71% of surgical, and 70% of major trauma patients received an inappropriate prophylaxis.

CONCLUSIONS

Most critically ill patients are at high or very high risk of VTE, but there is a low rate of appropriate prophylaxis. The efforts to improve the identification of patients at risk, and the implementation of appropriate prevention protocols should be enhanced.

Physicians declining patient enrollment in a critical care trial: a case study in thromboprophylaxis

PURPOSE

To analyze the frequency, rationale and determinants of attending physicians requesting that their eligible patients not be approached for participation in a thromboprophylaxis trial.

METHODS

Research personnel in 67 centers prospectively documented eligible non-randomized patients due to physicians declining to allow their patients to be approached.

RESULTS

In 67 centers, 3,764 patients were enrolled, but 1,460 eligible patients had no consent encounter. For 218 (14.9 %) of these, attending physicians requested that their patients not be approached. The most common reasons included a high risk of bleeding (31.2 %) related to fear of heparin bioaccumulation in renal failure, the presence of an epidural catheter, peri-operative status or other factors; specific preferences for thromboprophylaxis (12.4 %); morbid obesity (9.6 %); uncertain prognosis (6.4 %); general discomfort with research (3.7 %) and unclear reasons (17.0 %). Physicians were more likely to decline when approached by less experienced research personnel; considering those with[10 years of experience as the reference category, the odds ratios (OR) for physician refusals to personnel without trial experience was 10.47 [95 % confidence interval (CI) 2.19-50.02] and those with less than 10 years experience was 1.72 (95 % CI 0.61-4.84). Physicians in open rather than closed units were more likely to decline (OR 4.26; 95 % CI 1.27-14.34). Refusals decreased each year of enrollment compared to the pilot phase.

CONCLUSIONS

Tracking, analyzing, interpreting and reporting the rates and reasons for physicians declining to allow their patients to be approached for enrollment provides insights into clinicians' concerns and attitudes to trials. This information can encourage physician communication and education, and potentially enhance efficient recruitment.

Thromboprophylaxis patterns and determinants in critically ill patients: a multicenter audit

Introduction

Heparin is safe and prevents venous thromboembolism in critical illness. We aimed to determine the guideline concordance for thromboprophylaxis in critically ill patients and its predictors, and to analyze factors associated with the use of low molecular weight heparin (LMWH), as it may be associated with a lower risk of pulmonary embolism and heparin-induced thrombocytopenia without increasing the bleeding risk.

Methods

We performed a retrospective audit in 28 North American intensive care units (ICUs), including all consecutive medical-surgical patients admitted in November 2011. We documented ICU thromboprophylaxis and reasons for omission. Guideline concordance was determined by adding days in which patients without contraindications received thromboprophylaxis to days in which patients with contraindications did not receive it, divided by the total number of patient-days. We used multilevel logistic regression including time-varying, center and patient-level covariates to determine the predictors of guideline concordance and use of LMWH.

Results

We enrolled 1,935 patients (62.3 ± 16.7 years, Acute Physiology and Chronic Health Evaluation [APACHE] II score 19.1 ± 8.3). Patients received thromboprophylaxis with unfractionated heparin (UFH) (54.0%) or LMWH (27.6%). Guideline concordance occurred for 95.5% patient-days and was more likely in patients who were sicker (odds ratio (OR) 1.49, 95% confidence interval (CI) 1.17, 1.75 per 10-point increase in APACHE II), heavier (OR 1.32, 95% CI 1.05, 1.65 per 10-m/kg² increase in body mass index), had cancer (OR 3.22, 95% CI 1.81, 5.72), previous venous thromboembolism (OR 3.94, 95% CI 1.46,10.66), and received mechanical ventilation (OR 1.83, 95% CI 1.32,2.52). Reasons for not receiving thromboprophylaxis were high risk of bleeding (44.5%), current bleeding (16.3%), no reason (12.9%), recent or upcoming invasive procedure (10.2%), nighttime admission or discharge (9.7%), and life-support limitation (6.9%). LMWH was less often administered to sicker patients (OR 0.65, 95% CI 0.48, 0.89 per 10-point increase in APACHE II), surgical patients (OR 0.41, 95% CI 0.24, 0.72), those receiving vasoactive drugs (OR 0.47, 95% CI 0.35, 0.64) or renal replacement therapy (OR 0.10, 95% CI 0.05, 0.23).

Conclusions

Guideline concordance for thromboprophylaxis was high, but LMWH was less commonly used, especially in patients who were sicker, had surgery, or received vasopressors or renal replacement therapy, representing a potential quality improvement target.

Heparin-induced thrombocytopenia in the critically ill: interpreting the 4Ts test in a randomized trial

BACKGROUND

Thrombocytopenia occurs in 20% to 45% of critically ill medical-surgical patients. The 4Ts heparin-induced thrombocytopenia (HIT) score (with 4 domains: Thrombocytopenia, Timing of thrombocytopenia, Thrombosis and oTher reason[s] for thrombocytopenia) might reliably identify patients at low risk for HIT. Interobserver agreement on 4Ts scoring is uncertain in this setting.

OBJECTIVE

To evaluate whether a published clinical prediction rule (the "4Ts score") reliably rules out HIT in "low-risk" intensive care unit (ICU) patients as assessed by research coordinators (who prospectively scored) and 2 adjudicators (who scored retrospectively) during an international heparin thromboprophylaxis trial (PROTECT, NCT00182143).

METHODS

Of 3746 medical-surgical ICU patients in PROTECT, 794 met the enrollment criteria for this HIT substudy. Enrollment was predicated on one of the following occurring in ICU: platelets less than 50×10(9)/L, platelets decreased to 50% of ICU admission value (if admission value<100×10(9)/L), any venous thrombosis, or if HIT was otherwise clinically suspected. Independently, 4Ts scores were completed in real time by research coordinators blinded to study drug and laboratory HIT results, and retrospectively by 2 adjudicators blinded to study drug, laboratory HIT results, and research coordinators' scores; the adjudicators arrived at consensus in all cases. Of the 763 patients, 474 had a central or local laboratory HIT test performed and had 4Ts scoring by adjudicators; 432 were scored by trained research coordinators. Heparin-induced thrombocytopenia was defined by a centrally performed positive serotonin release assay (SRA).

RESULTS

Of the 474 patients with central adjudication, 407 (85.9%) had a 4Ts score of 3 or lower, conferring a low pretest probability (PTP) of HIT; of these, 6 (1.5% [95% confidence interval, 0.7%-3.2%) had a positive SRA. Fifty-nine (12.4%) had a moderate PTP (4Ts score of 4-5); of these, 4 (6.8%) had a positive SRA. Eight patients had a high PTP (4Ts score of ≥6); of these, 1 (12.5%) had a positive SRA. Raw agreement between research coordinators and central adjudication on each domain of the 4Ts score and low, intermediate, and high PTP was good. However, chance-corrected agreement was variable between adjudicators (weighted κ values of 0.31-0.93) and between the adjudicator consensus and research coordinators (weighted κ values of 0.13 and 0.78). Post hoc review of the 6 SRA-positive cases with an adjudicated low PTP demonstrated that their scores would have been increased if the adjudicators had had additional information on heparin exposure prior to ICU admission. In general, the fourth domain of 4Ts (oTher causes of thrombocytopenia) generated the most disagreement.

CONCLUSIONS

Real-time 4Ts scoring by research coordinators at the time of testing for HIT was not consistent with 4Ts scores obtained by central adjudicators. The results of this comprehensive HIT testing highlight the need for further research to improve the assessment of PTP scoring of HIT for critically ill patients.

Barriers and facilitators of thromboprophylaxis for medical-surgical intensive care unit patients: a multicenter survey

BACKGROUND

The objective of this study was to identify the self-reported barriers to and facilitators of prescribing low-molecular-weight heparin (LMWH) thromboprophylaxis in the intensive care unit (ICU).

METHODS

We conducted an interviewer-administered survey of 4 individuals per ICU (the ICU director, a bedside pharmacist, a thromboprophylaxis research coordinator, and physician site investigator) regarding LMWH thromboprophylaxis for medical-surgical patients in 27 ICUs in Canada and the United States. Items were generated by the research team and adapted from previous surveys, audits, qualitative studies, and quality improvement research. Respondents rated the barriers to LMWH use, facilitators (effectiveness, affordability, and acceptability thereof), and perceptions regarding LMWH use.

RESULTS

Respondents had 14.5 (SD, 7.7) years of ICU experience (response rate, 99%). The 5 most common barriers in descending order were as follows: drug acquisition cost, fear of bleeding, lack of resident education, concern about bioaccumulation in renal failure, and habit. The top 5 rated facilitators were preprinted orders, education, daily reminders, audit and feedback, and local quality improvement committee endorsement. Centers using preprinted orders (mean difference [P<.01]) and computerized physician order entry (P<.01) compared with those centers not using those tools reported higher affordability for these 2 facilitators. Compared with physicians and pharmacists, research coordinators considered ICU-specific audit and feedback of thromboprophylaxis rates to be a more effective, acceptable, and affordable facilitator (odds ratio, 6.67; 95% confidence interval, 1.97-22.53; P<.01). Facilitator acceptability ratings were similar within centers but differed across centers (P≤.01).

CONCLUSIONS

This multicenter survey found several barriers to use of LMWH including cost, concern about bleeding, and lack of resident knowledge of effectiveness. The diversity of reported facilitators suggests that large scale programs may address generic barriers but also need site-specific interprofessional knowledge translation activities.

[Prevention of venous thromboembolic disease in the critical patient: an assessment of clinical practice in the Community of Madrid]

OBJECTIVE

To analyze measures referred to venous thromboembolic prophylaxis in critically ill patients.

DESIGN

An epidemiological, cross-sectional (prevalence cut), multicenter study was performed using an electronic survey. Comparison of results with quality indexes of the Spanish Society of Intensive Care Medicine, the American College of Chest Physician guidelines and international studies.

SETTING

Intensive Care Units (ICUs) in the Community of Madrid (Spain).

PATIENTS

All patients admitted to the ICU on the day of the survey.

VARIABLES OF INTEREST

General aspects of venous thromboembolic prophylaxis and protocols used (risk stratification and ultrasound screening). A descriptive analysis was performed, continuous data being expressed as the mean or median, and categorical data as percentages.

RESULTS

A total of 234 patients in 18 ICUs were included. Eighteen percent (42/234) received no prophylaxis, and 55% had no contraindication to pharmacological prophylaxis. Of the 192 patients receiving prophylaxis, 84% received pharmacological prophylaxis, 14% mechanical prophylaxis and 2% combined prophylaxis. Low molecular weight heparin was the only pharmacological prophylaxis used, with a majority use of enoxaparin (17 of 18 ICUs). In patients with mechanical prophylaxis (31/192), antiembolic stockings were the most commonly used option (58%). Pharmacological prophylaxis contraindications were reported in 20% of the patients (46/234), the most frequent cause being thrombocytopenia (28% of the cases). Fifty percent of the ICUs used no specific venous thromboembolic prophylaxis protocol.

CONCLUSIONS

Pharmacological prophylaxis with low molecular weight heparin was the most frequently used venous thromboembolic prophylactic measure. In patients with contraindications to pharmacological prophylaxis, mechanical measures were little used. The use of combined prophylaxis was anecdotal. Many of our ICUs lack specific prophylaxis protocols.

Current prevention practice for venous thromboembolism in Japanese intensive care units

Venous thromboembolism (VTE) is a well-recognized life-threatening complication in the intensive care unit (ICU). However, no data have been reported regarding the prevalence and methods of prevention of VTE in Japanese ICUs. This study aimed to document the current practice of VTE prevention across a broad sample of medical-surgical ICU patients in Japan. In November 2010, we performed a point-prevalence survey of Japanese ICUs in training facilities for intensive care specialists. We recorded data from five consecutive ICU patients in each facility at any time on the day of the survey. A total of 470 patients were registered in this study. VTE prophylaxis was received by 85.3 % of participants. Of these, 69.8 % received mechanical prophylaxis and 12.5 % received pharmacological methods, with 17.7 % receiving both methods. Analyzing a comparison of the presence or absence of a hospital prevention protocol, the protocol group had higher rates of receiving prophylaxis (88.8 % vs. 80.0 %, P < 0.01) than the no-protocol group. In conclusion, VTE prophylaxis by mechanical methods was the main method in a high number of medical-surgical ICU patients in Japan. The ICUs with a hospital VTE prevention protocol in place performed significantly higher rates of prophylaxis than those without a protocol.

Coagulation Day 2010: an Austrian survey on the routine of thromboprophylaxis in intensive care

PURPOSE

Venous thromboembolism (VTE) is a common but often overlooked life-threatening complication of critical illness. The aim of this cross-sectional survey was to assess current practice of thromboprophylaxis as well as adherence to international guidelines.

METHODS

After ethics committee approval, all intensive care units in Austrian hospitals treating adult patients were invited to participate in this web-based survey. Anonymized data on each patient treated at the participating intensive care units on Coagulation Day 2010 were collected using an electronic case report form. Risk assessment, choice and monitoring of anticoagulants, means of mechanical prophylaxis, and demographic data were recorded.

RESULTS

Data from 325 critically ill patients were collected. Patients had a median of four risk factors for thrombosis and 6 % suffered from VTE. Of the 325 patients, 80 % received low molecular weight heparins subcutaneously, 10 % received unfractionated heparin intravenously, 1 % received alternative anticoagulants and 9 % received no pharmacological prophylaxis. Mechanical prophylaxis was used in 49 % with a predominant use of graduated compression stockings. In 39 % a combination of pharmacological and mechanical prophylaxis was applied and 5 % received no prophylaxis at all. Overall guideline adherence was 40 % on Coagulation Day 2010.

CONCLUSION

Current practice of thromboprophylaxis is predominantly based on the administration of low molecular weight heparins prescribed at rather arbitrary doses without a discernible relationship to drug monitoring, thromboembolic risk factors, vasopressor use or fluid balance. The use of mechanical prophylaxis, evaluation of risk scores and overall guideline adherence must be further encouraged by education, training and communication.

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.

Screening and prevention of venous thromboembolism in critically ill patients: a decision analysis and economic evaluation

RATIONALE

Venous thromboembolism is difficult to diagnose in critically ill patients and may increase morbidity and mortality.

OBJECTIVES

To evaluate the cost-effectiveness of strategies to reduce morbidity from venous thromboembolism in critically ill patients.

METHODS

A Markov decision analytic model to compare weekly compression ultrasound screening (screening) plus investigation for clinically suspected deep vein thrombosis (DVT) (case finding) versus case finding alone; and a hypothetical program to increase adherence to DVT prevention. Probabilities were derived from a systematic review of venous thromboembolism in medical-surgical intensive care unit patients. Costs (in 2010 $US) were obtained from hospitals in Canada, Australia, and the United States, and the medical literature. Analyses were conducted from a societal perspective over a lifetime horizon. Outcomes included costs, quality-adjusted life-years (QALY), and incremental cost-effectiveness ratios.

MEASUREMENTS AND MAIN RESULTS

In the base case, the rate of proximal DVT was 85 per 1,000 patients. Screening resulted in three fewer pulmonary emboli than case-finding alone but also two additional bleeding episodes, and cost $223,801 per QALY gained. In sensitivity analyses, screening cost less than $50,000 per QALY only if the probability of proximal DVT increased from a baseline of 8.5-16%. By comparison, increasing adherence to appropriate pharmacologic thromboprophylaxis by 10% resulted in 16 fewer DVTs, one fewer pulmonary emboli, and one additional heparin-induced thrombocytopenia and bleeding event, and cost $27,953 per QALY gained. Programs achieving increased adherence to best-practice venous thromboembolism prevention were cost-effective over a wide range of program costs and were robust in probabilistic sensitivity analyses.

CONCLUSIONS

Appropriate prophylaxis provides better value in terms of costs and health gains than routine screening for DVT. Resources should be targeted at optimizing thromboprophylaxis.

Thromboprophylaxis in Intensive Care: A Nationwide, Multidisciplinary Quality Improvement Project

Patients admitted to intensive care units (ICUs) are at high risk of developing venous thromboemboli. Pharmacological thromboprophylaxis is efficacious in critically ill patients; however, prescription of such agents is often found to be suboptimal. The aim of this study was to assess the quality of pharmacoprophylaxis prescribing across Scottish ICUs, and to introduce measures to improve this. A point-prevalence survey of thromboprophylaxis was followed by a pharmacist-delivered intervention and a subsequent point-prevalence survey, in 22 Scottish ICUs. In the initial survey, 15% of eligible patients (n=94) were not receiving pharmacoprophylaxis, while 10% of ineligible patients had thromboprophylaxis prescribed. A quality improvement programme was instituted with pharmacist-delivered daily checks for thromboprophylaxis prescription, prompting of medical staff and local checklists. Following implementation of the intervention, a repeat survey of 130 patients revealed that the rate of eligible patients receiving thromboprophylaxis rose to 96%, (p=0.02, relative risk reduction 0.89). Additionally mechanoprophylaxis use increased and those receiving no prophylaxis fell to 8% (p=0.005 relative risk reduction 0.85). The rate of prescription of thromboprophylaxis to ineligible patients was 14% (p=0.65). A simple intervention led to significant improvements in the use of thromboprophylaxis in ICU, with an effect achievable on a national scale.

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.

Effect of time of admission on compliance with deep vein thrombosis prophylaxis in a tertiary medical intensive care unit

OBJECTIVE

We sought to evaluate deep vein thrombosis (DVT) prophylaxis compliance according to time of admission in a medical intensive care unit (MICU).

METHODS

This was a retrospective cohort study at a closed tertiary MICU. We classified patients into three groups (week days, weekends, and week nights), according to time of admission. An unweighted risk factor score (RFS) was calculated from 20 known risk factors. We defined DVT prophylaxis compliance as any type of prophylaxis (mechanical or pharmacologic) for RFS 3. Non-compliance was defined as no prophylaxis or single-type prophylaxis for RFS > 3.

RESULTS

We analyzed 105 admissions. Eighty (76.19%) patients received compliant DVT prophylaxis, and 25 (23.81%) patients received non-compliant regimens of whom 11 (10.48%) were not on any prophylaxis. DVT prophylaxis compliance was not different across the three admission groups. The non-compliant DVT prophylaxis group had a higher RFS (3.48 +/- 2.1 vs. 2.25 +/- 1.5; P = 0.011), a trend towards fewer female patients (40% vs. 60%; P = 0.079), and a higher percentage of admissions by interns at the first postgraduate year (PGY) level (28% vs. 5.4%; P = 0.01). Logistic regression revealed that only RFS and PGY level were independent predictors for compliance (P = 0.015 and 0.005 respectively). Time of admission was not a significant factor.

CONCLUSIONS

Time of admission did not influence DVT prophylaxis compliance. Compliance improved with higher PGY level and lower RFS. A higher level of knowledge probably explains the association with PGY level; however, we cannot explain the inverse relationship between RFS and compliance.

[Prevention of thromboembolism in German intensive care units : Results of a nationwide survey]

BACKGROUND

Intensive care unit (ICU) patients have a high risk of developing venous thromboembolism (VTE) and prophylaxis is recommended. Venous thromboembolism confers considerable morbidity and mortality in hospitalized patients, although few studies have focused on critically ill patients.

METHOD AND OBJECTIVE

A systematic prospective mailed self-administered survey of 645 German ICU directors was performed, representing 652 ICUs throughout the country. The objective of this study was to understand current approaches to the prevention of VTE among patients in ICUs.

RESULTS

Of the 652 ICUs approached, 470 (72.3%) participated. Thromboembolism prophylaxis was prescribed in 98% of the ICUs. For mechanical prophylaxis graded elastic stockings were used in 93% and pneumatic compression devices in 24%. For pharmacologic prophylaxis low molecular weight heparin was the predominant prophylactic strategy in 88%, whereas unfractionated heparin was used less often in 45%.

CONCLUSION

The prescribed prophylaxis for thromboembolism in 98% of the German ICUs is surprisingly high compared to that given in the literature. A combination of mechanical and pharmacologic prophylaxis is the predominant prophylactic strategy.

[Risk of venous thromboembolism in acute medical illnesses. Part 2: Situations at risk in ambulatory, hospital and internal medicine settings]

PURPOSE

The increased risk of thromboembolism in acute medical illnesses (AMI) is difficult to assess because of the diversity of medical conditions. The first part of this review of the literature was dedicated to methods of risk analysis based on our current pathophysiological knowledge. This second part describes more specifically the risk of venous thrombosis linked to AMI in hospital, ambulatory and internal medicine settings.

CURRENT KNOWLEDGE AND KEY POINTS

The incidence of venous thromboembolism is higher in hospital than in ambulatory setting, albeit the latter remains significant. Stroke and affections leading to intensive care management represent conditions at great risk. Several mechanisms leading to a prothrombotic state have been identified, explaining the increased risk observed during relapses of pathologies specifically treated in internal medicine such as lupus erythematosus, Wegener granulomatosis, inflammatory bowel diseases and Behcet's disease.

FUTURE PROSPECTS AND PROJECTS

Next to the pathophysiological understanding of venous thrombosis, the assessment of the specific thrombogenic burden of an AMI is an additive tool to screen medical patients at high risk. This systematic review of the literature shows uncertainties towards some risk factors as bedrest or acute inflammatory response. Taking into account the methodological difficulties inherent to prospective and epidemiological studies, a meta-analysis focusing on these factors would be useful to refine prevention guidelines for venous thromboembolism in medical setting.

Knowledge translation in critical care: factors associated with prescription of commonly recommended best practices for critically ill patients

OBJECTIVE

To describe prescription rates of commonly recommended best practices (clinical interventions with a strong base of evidence supporting their implementation) for critically ill patients and determine factors associated with increased rates of prescription.

DESIGN

A retrospective observational study.

SETTING

A university-affiliated medical-surgical-trauma intensive care unit over a 1-yr period.

PATIENTS

One hundred randomly selected critically ill patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among the best practices studied, there was great variability in the proportion of patients eligible (median 36.5%, range 10% to 100%) and the proportion without contraindication (32.5%, range 10% to 86%) for each practice. The median rate of prescription of best practices for eligible patients was 56.5%, with a range from 8% to 95%. There was greater prescription of best practices when standard admission orders included an option to prescribe them (p = .048). Among those practices with standard admission orders, there was greatest prescription for practices additionally having a specialty consultation service (p = .004). There was an inverse association between severity of illness and prescription of best practices (p = .001): Sicker patients were less likely to be prescribed best practices.

CONCLUSIONS

There may be substantial variability in the acceptance and prescription of commonly recommended best practices for critically ill patients. Standard order sets and focused specialty consultation may improve knowledge translation and prescription of best practice.

Mechanical Thromboprophylaxis in Critically Ill Patients: A Systematic Review and Meta-Analysis

• Objective To systematically review the randomized trials, observational studies, and survey evidence on compression and pneumatic devices for thromboprophylaxis in intensive care patients.

• Methods Published studies on the use of compression and pneumatic devices in intensive care patients were assessed. A meta-analysis was conducted by using the randomized controlled trials.

• Results A total of 21 relevant studies (5 randomized controlled trials, 13 observational studies, and 3 surveys) were found. A total of 811 patients were randomized in the 5 randomized controlled trials; 3421 patients participated in the observational studies. Trauma patients only were enrolled in 4 randomized controlled trials and 4 observational studies. Meta-analysis of 2 randomized controlled trials with similar populations and outcomes revealed that use of compression and pneumatic devices did not reduce the incidence of venous thromboembolism. The pooled risk ratio was 2.37, indicative of favoring the control over the intervention in reducing the deep venous thrombosis; however, the 95% CI of 0.57 to 9.90 indicated no significant differences between the intervention and the control. A range of methodological issues, including bias and confounding variables, make meaningful interpretation of the observational studies difficult.

• Conclusions The limited evidence suggests that use of compressive and pneumatic devices yields results not significantly different from results obtained with no treatment or use of low-molecular-weight heparin. Until large randomized controlled trials are conducted, the role of mechanical approaches to thromboprophylaxis for intensive care patients remains uncertain.

Anti-Xa activity after subcutaneous administration of dalteparin in ICU patients with and without subcutaneous oedema: a pilot study

INTRODUCTION

Intensive care unit (ICU) patients often suffer from subcutaneous oedema, due to administration of large fluid volumes and the underlying pathophysiological condition. It is unknown whether the presence of subcutaneous oedema impairs the absorption of dalteparin, a low molecular weight heparin, when it is given by subcutaneous administration for venous thromboembolism prophylaxis. The objective of this study is to compare the anti-Xa activity of dalteparin after subcutaneous administration in ICU patients with and without subcutaneous oedema.

METHODS

This non-randomized open parallel group follow-up pilot study was conducted in two mixed medical-surgical intensive care units at two teaching hospitals. Seven ICU patients with subcutaneous oedema (index group) and seven ICU patients without subcutaneous oedema (reference group) were studied. Anti-Xa activity was determined at 0, 3, 4, 6, 8, 12 and 24 hours after subcutaneous administration of 2,500 IU dalteparin. Plasma concentrations of factor anti-Xa activity were measured using a chromogenic factor Xa inhibition assay.

RESULTS

The characteristics of the index group were: age, 58 years; male/female ratio, 5/2; body mass index at admission, 23.4 kg/m2 (at study day, 30.6 kg/m2). The characteristics of the reference group were: age, 49 years; male/female ratio, 6/1; body mass index at admission, 24.8 kg/m2 (at study day, 25.0 kg/m2). In the index group, creatinine clearance was lower compared to the reference group (71 versus 131 ml/minute, p = 0.003). Sequential organ failure assessment score did not differ between index and reference groups (4 versus 5). Mean arterial pressure was comparable between index and reference groups (91 versus 95 mmHg) and within the normal range. The mean Cmax value was not different between ICU patients with and without subcutaneous oedema (0.15 +/- 0.02 versus 0.14 +/- 0.02 IU/ml, p = 0.34). In the index group, the mean AUC(0-24 h) value was slightly higher compared with the reference group (1.50 +/- 0.31 versus 1.15 +/- 0.25 h.IU/ml, p = 0.31). This difference was not significant.

CONCLUSION

In this pilot study, there was no clinically relevant difference in anti-Xa activity after subcutaneous administration of 2,500 IU dalteparin for venous thromboembolism prophylaxis between ICU patients with and without subcutaneous oedema. Critically ill patients seem to have lower anti-Xa activity levels than healthy volunteers.

Prophylactic low-molecular-weight heparin: Prescription practice in an intensive care unit

AIM

The aim of this study was to review the use of low-molecular-weight heparin (LMWH) in a medical intensive care unit.

MATERIALS AND METHODS

Double-blind prospective study conducted in a 14-bed intensive care unit, covering all patients admitted over a 2-month period. A comparison with 2 guidelines based on indication, age of the patient, kidney function, platelet count, and duration of treatment was performed. Bleeding complication and clinically diagnosed phlebitis episodes were collected.

RESULTS

One hundred thirty-six patients (71 treated with LMWH and 65 untreated) were included in the study (mean age, 60 +/- 18 years; SAPS (Simplified Acute Physiology Score) II, 39 +/- 23). Among treated patients, 9 were overtreated (13%), and among nontreated patients, 13 were undertreated (20%). In the cohort of treated patients, reasons for failure to comply with recommendations included age of the patient (30%), creatinine clearance (18%), platelet count (32.4%), and duration of treatment (12.7%). Low-molecular-weight heparin prescriptions were conforming to the 4 criteria in 35.2% of patients, to 3 in 43.7%, to 2 in 19.7%, and to 1 in 1.4%.

CONCLUSION

The prescription of prophylactic LMWH in intensive care has become a routine. Our study shows that over- and underprescription are common together with misuse.

Incorrect use of thromboprophylaxis for venous thromboembolism in medical and surgical patients: results of a multicentric, observational and cross-sectional study in Brazil

OBJECTIVES

Although effective strategies for the prevention of venous thromboembolism (VTE) are widely available, a significant number of patients still develop VTE because appropriate thromboprophylaxis is not correctly prescribed. We conducted this study to estimate the risk profile for VTE and the employment of adequate thromboprophylaxis procedures in patients admitted to hospitals in the state of São Paulo, Brazil.

METHODS

Four hospitals were included in this study. Data on risk factors for VTE and prescription of pharmacological and non-pharmacological thromboprophylaxis were collected from 1454 randomly chosen patients (589 surgical and 865 clinical). Case report forms were filled according to medical and nursing records. Physicians were unaware of the survey. Three risk assessment models were used: American College of Chest Physicians (ACCP) Guidelines, Caprini score, and the International Union of Angiololy Consensus Statement (IUAS). The ACCP score classifies VTE risk in surgical patients and the others classify VTE risk in surgical and clinical patients. Contingency tables were built presenting the joined distribution of the risk score and the prescription of any pharmacological and non-pharmacological thromboprophylaxis (yes or no).

RESULTS

According to the Caprini score, 29% of the patients with the highest risk for VTE were not prescribed any thromboprophylaxis. Considering the patients under moderate, high or highest risk who should be receiving prophylaxis, 37% and 29% were not prescribed thromboprophylaxis according to ACCP (surgical patients) and IUAS risk scores, respectively. In contrast, 27% and 42% of the patients at low risk of VTE, according to Caprini and IUAS scores, respectively, had thromboprophylaxis prescribed.

CONCLUSION

Despite the existence of several guidelines, this study demonstrates that adequate thromboprophylaxis is not correctly prescribed: high-risk patients are under-treated and low-risk patients are over-treated. This condition must be changed to insure that patients receive adequate treatment for the prevention of thromboembolism.

Prophylaxis of Thromboembolism in Critical Care (PROTECT) Trial: a pilot study

PURPOSE

There is no randomized trial comparing low-molecular weight heparin (LMWH) and unfractionated heparin (UFH) for thromboprophylaxis in medical-surgical ICU patients. The primary objective of this randomized pilot study on LMWH vs UFH was to assess the feasibility of conducting a large randomized trial with respect to timely enrollment and blinded study drug administration, practicality of twice-weekly lower limb ultrasounds to screen for deep venous thrombosis, LMWH bioaccumulation and dose adjustment in renal insufficiency, and recruitment rates for a future trial in medical-surgical intensive care unit (ICU) patients. Its additional goals were to evaluate the suitability of the exclusion criteria and to document the range of research activities that precede accrual of patients into a trial to plan multisite management.

MATERIALS AND METHODS

By computerized telephone randomization, we allocated 129 medical-surgical ICU patients to treatment with dalteparin 5,000 IU QD SC or that with UFH 5,000 IU BID SC. Within each clinical center, only the study pharmacist was not blinded. We performed bilateral lower limb compression ultrasounds within 48 hours of ICU admission, twice weekly, on suspicion of deep venous thrombosis, and 7 days after ICU discharge. Research coordinators and investigators at 7 centers reported the time they engaged in all research activities before the first patient was randomized.

RESULTS

Timely complete study drug administration occurred after enrollment. More than 99% of scheduled doses were administered in a blinded fashion. Scheduled ultrasounds were performed without exception. No bioaccumulation of dalteparin was observed when creatinine clearance decreased to lower than 30 mL/min. Average recruitment was 2 patients/center per month before the study exclusion criteria were modified. Study startup activities required, on average, 65.5 hours of combined investigator and research coordinator time at each center. Careful examination of the accrual in the pilot study led to a reexamination of the Prophylaxis of Thromboembolism in Critical Care Trial (PROTECT) study exclusion criteria.

CONCLUSIONS

This pilot study suggests that a multicenter randomized clinical trial comparing LMWH with UFH in critically ill medical-surgical patients is feasible. Pilot studies can improve the design of larger trials and may enhance successful timely completion.

Dalteparin thromboprophylaxis for critically ill medical-surgical patients with renal insufficiency

PURPOSE

Thromboprophylaxis with low-molecular-weight heparin (LMWH) may be more effective than unfractionated heparin but also more likely to bioaccumulate and potentially cause bleeding in patients with renal insufficiency. The objectives of this study were to assess, among medical-surgical patients in the intensive care unit receiving dalteparin 5,000 IU daily for thromboprophylaxis, (1) the relationship between renal dysfunction and LMWH bioaccumulation as measured by trough anti-Xa levels, (2) the relationship between renal dysfunction and risk of bleeding as measured by a surrogate marker (peak anti-Xa levels), and (3) the relationship between anti-Xa levels, bleeding events, and thrombotic events.

MATERIALS AND METHODS

In this prospective single-center cohort study, we enrolled patients 18 years or older, expected to stay 72 hours or longer, and with a creatinine clearance 30 mL/min or higher at intensive care unit admission. We administered 5,000 IU dalteparin subcutaneously each day. The main phase 1 objective was to detect bioaccumulation of dalteparin by measuring trough anti-Xa levels (22-23 hours post dalteparin). The main phase 2 objective was to examine the relationship between renal dysfunction and peak anti-Xa levels (4 hours post dalteparin). We recorded creatinine clearance daily and bleeding and thrombotic events, blinded to anti-Xa levels.

RESULTS

We enrolled 19 patients aged 62.7 (13.2) years with an APACHE II score of 23.5 (9.4). We measured trough anti-Xa levels on 185 occasions in 19 patients; we measured peak anti-Xa levels on 113 occasions in 11 patients. We identified no bioaccumulation of LMWH in this study, as detected by trough anti-Xa levels. Most peak anti-Xa levels were in the conventional prophylactic range.

CONCLUSIONS

When administered in prophylactic doses to critically ill patients with a wide range of calculated creatinine clearances, we found no evidence of bioaccumulation of dalteparin. If dalteparin does not bioaccumulate, it may be an attractive alternative agent for thromboprophylaxis.

Thromboprophylaxis for intensive care patients in Australia and New Zealand: a brief survey report

PURPOSE

Internationally, there is practice variation concerning optimal thromboprophylaxis for patients in the intensive care unit (ICU). The current practice in Australia and New Zealand is unknown.

METHOD

We conducted a self-administered e-mail survey of 22 Australian and New Zealand ICUs expressing interest in participating in a proposed international randomized trial (PROphylaxis for ThromboEmbolism in Critical Care Trial).

RESULTS

Our response rate was 95.4% (95% CI, 77%-100%). Of participating ICUs, 90.5% (95% CI, 70%-99%) used subcutaneous unfractionated heparin for routine thromboprophylaxis in ICU patients. Low-molecular-weight heparin was reserved for specific high-risk patients in many units.

CONCLUSION

Routine thromboprophylaxis for ICU patients in Australia and New Zealand is similar to Canada but different to France. Optimal thromboprophylaxis for ICU patients is currently unclear in the absence of randomized trial data.

Heparin, Low Molecular Weight Heparin, and Heparin-Induced Thrombocytopenia in the ICU

Thrombocytopenia is common in critically ill patients who receive heparin. However, heparin-induced thrombocytopenia (HIT) is a relatively uncommon explanation for thrombocytopenia in this patient population. This article describes clinical features of HIT and interpretation of laboratory tests for HIT antibodies from the perspective of the intensive care unit.

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.

Venous thromboembolism prophylaxis in medical patients: Future perspectives

Venous thromboembolism is a common potentially life-threatening complication in acutely ill medical patients. Actually, over 70% fatal episodes of pulmonary embolism during hospitalization occur in non-surgical patients. In the absence of thromboprophylaxis, the incidence of venographically detected deep vein thrombosis is about 15% in medical patients and several trials and meta-analyses have clearly demonstrated the prophylactic role of unfractioned heparin and low-molecular-weight heparins. Although over the last years the knowledge of epidemiology, clinical features and prophylaxis in medical patients has significantly improved, there are still several relevant issues to investigate thoroughly. Scarce data are available on a simple way to stratify patients in order to identify those who should undergo prophylaxis and several studies clearly show that thromboprophylaxis in medical conditions is underused. Moreover, in comparison to surgical settings, very few randomized clinical trials on the efficacy of pharmacologic prophylaxis have been performed and no data at all have been published concerning mechanical prophylaxis in medical conditions. According to previous studies and results of very recently published trials, new data are available to tailor low molecular weight heparin optimal dose, whereas the optimal duration of prophylaxis in medical patients is still a matter of debate. Moreover, the possible role of the new antithrombotic drugs in the venous thromboembolism prevention in medical conditions and the optimal management of thromboprophylaxis in patients with ischaemic stroke have not been fully investigated. Although new evidence represents a significant improvement both in stratification of VTE risk and in decisions about the appropriate type and duration of prophylactic strategies in medical patients, additional data are still needed.

Prophylaxis of venous thromboembolism in medical patients

PURPOSE OF REVIEW

Venous thromboembolism is a multifactorial silent disease and tends not to be suspected by physicians, especially in medical patients. Pulmonary embolism is the most preventable cause of death among hospitalized patients. It is of major importance to assess the risk for venous thromboembolism and to adapt the prophylactic strategy with the aim of improving the risk-benefit ratio of the prophylaxis.

RECENT FINDINGS

Prophylaxis of venous thromboembolism can be done by either mechanical means or pharmacologic agents or both. The Medenox trial, the Prime study, the Prince study, the Prevent study, and the Artemis trial demonstrated that acutely ill medical patients are at increased risk of venous thromboembolism and that low molecular weight heparins (enoxaparin 40 mg or dalteparin 5000 IU subcutaneously once daily for 10 days) as well as fondaparinux 2,5 mg subcutaneously once daily for 10 days have a favorable risk-benefit ratio in the prevention of venous thromboembolism in acutely ill medical patients. The publication of the results of the Exclaim study is expected to clarify the optimal duration of prophylaxis in this group of patients. Patients hospitalized in medical intensive care units as well as patients with active cancer or central venous catheters are at increased risk of venous thromboembolism, and the studies published so far demonstrate the favorable risk-benefit ratio of thromboprophylaxis with either low molecular weight heparins or low-dose warfarin.

SUMMARY

Acutely ill medical patients are at increased risk of venous thromboembolism. Prophylaxis with low molecular weight heparins and fondaparinux is effective and safe. Initiatives to improve venous thromboembolism prophylaxis should be based on the education of physicians regarding the individualized risk assessment.