Antifactor Xa Levels in Four Patients with Burn Injuries Who Received Enoxaparin to Prevent Venous Thromboembolism

Yogaratnam, Dinesh; Smith, Brian S.; Angood, Peter B.; Gandhi, Pritesh J.

doi:10.1592/phco.24.17.1793.52344

Cited by 17 publications

(14 citation statements)

References 25 publications

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“…24 Approximately 48 hours postinjury, burn patients become hyperdynamic with an increased cardiac output, resulting in enhanced hepatic and renal clearance of drugs. In a case series by Yogaratnam et al 15 providers saw an increase in anti-Xa levels (above 0.4 U/ ml) in two of their four patients later in their hospital stay (more than 28 days postadmission). 22,26 However, when the acute phase of burn injury resolves and the enoxaparin dose-response relationship normalizes is unknown.…”

Section: Discussionmentioning

confidence: 89%

Evaluation of an Enoxaparin Dosing Calculator Using Burn Size and Weight

Faraklas

Ghanem

Brown

et al. 2013

Journal of Burn Care & Research

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Previous research has shown that inadequate antifactor Xa levels (anti-Xa) occur in burn patients and may increase the risk of venous thromboembolic events (VTE). The objective of this retrospective review was to investigate the usefulness of an enoxaparin dosing algorithm using a previously published equation. With institutional review board approval, all acute burn patients at an American Burn Association-verified regional burn center who were treated with enoxaparin for VTE prophylaxis and had at least one anti-Xa from May 1, 2011 to December 15, 2012 were included. Patients with subprophylactic anti-Xa received increased enoxaparin dose per unit protocol with the goal of obtaining a prophylactic anti-Xa (0.2-0.4 U/ml). Sixty-four patients were included in our analysis. The regression equation was used in 33 patients for initial enoxaparin dosing (Eq) whereas 31 patients received traditionally recommended prophylaxis dosing (No-Eq). Groups were comparable in sex, age, weight, inhalation injury, and burn size. Initial enoxaparin dosing in Eq was significantly more likely to reach target than in No-Eq (73 vs 32%; P = .002). No episodes of hemorrhage, thrombocytopenia, or heparin sensitivity were documented in either group. Median final enoxaparin dose required to reach prophylactic level was 40 mg every 12 hours (range, 30-80 mg). Twenty-one No-Eq patients ultimately reached target, and 11 of these final doses were equivalent to or greater than the predicted equation. Ten patients never reached prophylactic anti-Xa before enoxaparin was discontinued (nine from No-Eq). Two patients, one from each group, developed VTE complications despite appropriate anti-Xa for prophylaxis. A strong correlation was shown between weight, burn size, and enoxaparin dose (r = .68; P < .001). Use of the enoxaparin dosing algorithm significantly increased the frequency of obtaining a target initial anti-Xa. There were no bleeding complications. Enoxaparin dosing correlates to burn size and weight, making a standard dose inappropriate because patient habitus and extent of burn injury are highly variable. This simple equation improves enoxaparin dosing for acute adult burn patients.

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Section: Discussionmentioning

confidence: 89%

Evaluation of an Enoxaparin Dosing Calculator Using Burn Size and Weight

Faraklas

Ghanem

Brown

et al. 2013

Journal of Burn Care & Research

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“…[11][12][13][14] The activity of nadroparin was significantly reduced in ICU patients receiving vasopressor medications compared with both ICU patients not receiving vasopressors and general surgery patients. 11 Because aggressive volume resuscitation is often administered to patients receiving vasopressors in the ICU, it is possible that these patients had significant peripheral edema that may have contributed to the observed reduction in plasma anti-Xa activity, similar to the findings in our study.…”

Section: Discussionmentioning

confidence: 99%

“…[11][12][13][14] The results emphasize the need for additional research to define the optimal treatment option, dose, and route of administration for the prevention of VTE in critically ill patients. The SC route of administration may lead to poor and erratic drug absorption in critically ill patients due to poor local perfusion in the setting of reduced cardiac output, peripheral edema, hypotension, or localized vasoconstriction.…”

Section: Enoxaparin Pharmacokinetics In Trauma Icu Patientsmentioning

confidence: 94%

“…9,10 Several recent studies have reported altered pharmacokinetics of LMWH products in critically ill patients leading to subtherapeutic plasma anti-Xa activity. [11][12][13][14] However, none of these studies specifically enrolled ICU patients with multiple trauma, evaluated the enoxaparin dose most commonly recommended for prevention of VTE in the trauma population, or attempted to study the influence of marked peripheral edema, which is a common finding in the ICU.…”

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confidence: 99%

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Pharmacokinetics and Pharmacodynamics of Enoxaparin in Multiple Trauma Patients

Haas

Nelsen

Raghavendran

et al. 2005

The Journal of Trauma: Injury, Infection, and Critical Care

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“…One observational study of four burn patients showed that standard starting dosage of enoxaparin in surgical patients was not adequate to achieve goal antifactor Xa peak levels. 9 We hypothesized that low antifactor Xa levels would be found in our acute burn patients as well. Therefore, we began monitoring antifactor Xa levels to ensure adequate enoxaparin therapy on June 1, 2009.…”

mentioning

confidence: 97%

Enoxaparin and Antifactor Xa Levels in Acute Burn Patients

Lin

Faraklas

Cochran

et al. 2011

Journal of Burn Care & Research

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Altered pharmacokinetics in critically ill patients have been shown to result in inadequate enoxaparin dosing for venous thromboembolism (VTE) prophylaxis. In the burn unit, routine monitoring of antifactor Xa levels was implemented to ensure adequate VTE prophylaxis. The purpose of this study was to examine the appropriateness of enoxaparin dosing for VTE prophylaxis in this specialized patient population. The authors reviewed patients with acute burn injury from June 1, 2009, to October 20, 2009, who had enoxaparin therapy monitored with antifactor Xa levels. Data collection occurred prospectively. Thirty-eight patients received enoxaparin subcutaneously for prophylaxis of VTE and had antifactor Xa levels measured. Thirty (79%) patients had initial antifactor Xa levels less than 0.2 U/ml. Enoxaparin dosages were subsequently increased as needed to achieve antifactor Xa levels of 0.2 to 0.4 U/ml. Eight of 38 patients never achieved goal antifactor Xa level before enoxaparin was discontinued. The median final dose required to achieve an antifactor Xa level within therapeutic range was 50 mg every 12 hours (range 30-70 mg). In linear regression, final enoxaparin dose correlated with TBSA. Two patients had clinically significant thromboembolic events. There were no documented episodes of significant hemorrhage, thrombocytopenia, or heparin-associated allergy. The low antifactor Xa levels observed in this study demonstrate that standard dosing of enoxaparin for VTE prophylaxis is inadequate for patients with acute burns. In these patients, both a higher initial enoxaparin dose and routine monitoring of antifactor Xa levels are recommended.

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Antifactor Xa Levels in Four Patients with Burn Injuries Who Received Enoxaparin to Prevent Venous Thromboembolism

Cited by 17 publications

References 25 publications

Evaluation of an Enoxaparin Dosing Calculator Using Burn Size and Weight

Evaluation of an Enoxaparin Dosing Calculator Using Burn Size and Weight

Pharmacokinetics and Pharmacodynamics of Enoxaparin in Multiple Trauma Patients

Enoxaparin and Antifactor Xa Levels in Acute Burn Patients

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