Use of a Modified Dosing Weight for Heparin Therapy in a Morbidly Obese Patient

Schwiesow, Sarah; Wessell, Andrea M.; Steyer, Terrence E.

doi:10.1345/aph.1e300

Cited by 18 publications

(11 citation statements)

References 12 publications

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“…A case report of a 54-year-old morbidly obese (182.4 kg, BMI 75 kg/m 2 ) woman treated with heparin for a highly probable pulmonary embolism described the use of a modified DW (average of IBW and ABW) of 120 kg to calculate the heparin bolus (80 units/kg [9600 units]) and initial infusion rate (18 units/kg/hr [2160 units/hr]). 17 A therapeutic aPTT (target range 70-115 sec; equivalent to a heparin concentration of 0.3-0.7 units/ml) was achieved in this patient within 10 hours with the initial infusion rate of 2160 units/hour. The heparin aPTT was maintained at the higher end (94.7-116.9 sec) of the target aPTT range (70-115 sec) for the duration of therapy (6 days).…”

Section: Reports From the Centers For Disease Control And Prevention mentioning

confidence: 72%

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Unfractionated Heparin Dosing for Venous Thromboembolism in Morbidly Obese Patients: Case Report and Review of the Literature

2010

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Unfractionated heparin infusion therapy is often administered using a weight-based dosing strategy for the treatment of venous thromboembolism. In the last several decades, the prevalence of obesity in the United States has increased significantly. The applicability of weight-based heparin dosing recommendations in the obese and morbidly obese population is uncertain, as limited data are available. We describe a 388-kg man who was started on an intravenous infusion of heparin according to hospital protocol for suspected pulmonary embolism. The patient was given a 5000-unit heparin bolus followed by an initial heparin infusion rate of 1500 units/hour, the maximum initial rate specified in the protocol. After additional infusion rate adjustments, a therapeutic activated partial thromboplastin time (aPTT) was reached 55 hours later with a heparin infusion rate of 3650 units/hour. Due to concerns of heparin-induced thrombocytopenia, heparin therapy was discontinued, and fondaparinux 5 mg/day was started. However, heparin therapy was restarted 4 days later for persistent, refractory hypoxemia and recurrent concerns of possible pulmonary embolism. During this second course, a therapeutic aPTT was achieved with a heparin infusion rate of 3550 units/hour. The patient developed bloody pulmonary secretions (with a therapeutic aPTT), necessitating the discontinuation of the heparin infusion. The patient later died after developing pulseless electrical activity. Standard weight-based heparin dosing protocols that specify maximum doses for initial bolus and infusion rates can result in significant delays in time to achieve therapeutic anticoagulation in the obese and morbidly obese patient. Despite limited data on heparin dosing in obesity, we recommend the use of a dosing weight to determine initial heparin dosing when treating venous thromboembolism in morbidly obese patients. It is reasonable to consider one of the following formulas: dosing weight = ideal body weight (IBW) + 0.3(actual body weight [ABW] - IBW), or dosing weight = IBW + 0.4(ABW - IBW).

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Section: Reports From the Centers For Disease Control And Prevention mentioning

confidence: 72%

“…A variety of case reports and retrospective studies were identified. [11][12][13][14][15][16][17][18] References of the articles were reviewed to identify additional literature. The variability in the weight evaluated-ABW versus dosing weight (DW)-and in the definition of obesity used limits the ability to draw a definitive recommendation on the best approach.…”

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confidence: 99%

Unfractionated Heparin Dosing for Venous Thromboembolism in Morbidly Obese Patients: Case Report and Review of the Literature

2010

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“…Additionally, Riney et al have found that the required heparin dose per kilogram of body weight for high BMI patients was obviously lower than that for low BMI patients to reach similar APTT values (18). Therefore, the heparin loading doses could be administered according to ideal body weight, corrected weight, or dose of heparin per blood volume of the obese patients to avoid bleeding complications that was still lack of practical clinical researches (17). In conclusion, the results of our study have shown that a standardized dosing nomogram that uses the actual body weight to calculate the heparin doses may result in UFH overdose for patients with higher BMI compared to patients with lower BMI.…”

Section: Discussionmentioning

confidence: 99%

Influence of Body Mass Index on the Activated Clotting Time Under Weight‐Based Heparin Dose

Hong

Shan

Huang

et al. 2014

Clinical Laboratory Analysis

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“…Multiple case reports have suggested the use of various modified or adjusted ''dosing weight'' (DW) for calculation of doses in obese patients (30)(31)(32). Delays varied from 10 to 48 hours to achieve a threshold aPTT.…”

Section: Obesitymentioning

confidence: 99%

Delayed efficient anticoagulation with heparin in patients with a weight of 110 kg and more treated for acute coronary syndrome

Joncas

Poirier

Ardilouze

et al. 2013

Obesity

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Objective: The use of a weight-based nomogram is considered as standard care for prescribing appropriate doses of unfractionated heparin (UFH). Because of the need for multiple other medications that may affect bleeding and that clinical data have relied on similar dosing algorithms, maximum initial bolus and infusion rates have been suggested (capped initial dose). Whether these weight-based heparin nomograms properly address therapeutic dosing in obese patients remains questionable. Design and Methods: Thirty patients treated for acute coronary syndrome and weighing !110 kg were retrospectively compared with 90 controls (three groups of 30 patients, weighting 50-69.9, 70-89.9, or 90-109.9 kg), all treated with UFH, July 2008 to April 2009. The primary end point was the time required to obtain a threshold activated partial thromboplastin time (aPTT). Results: Mean time to achieve threshold aPTT was longer for obese patients weighing !110 kg than for controls (31.47 vs. 12.89 hours; P < 0.0001). At 24 hours, 63% of obese patients weighing !110 kg had not reached threshold aPTT vs. 7% of controls (P < 0.0001). However, threshold infusion rate did not differ between weight categories (13.0 vs. 13.1 U/kg/h; P ¼ NS) and approximated the initial infusion rate recommended by nomograms without applying the dose cap (12 U/kg/h). Conclusions: Adequate anticoagulation time doubled in patients weighing !110 kg, suggesting that these patients were not receiving appropriate heparin doses initially to achieve threshold aPTT rapidly. Using initial infusion rate recommended by a nomogram without capping for total body weight is suggested as acceptable in this study. This approach should be further evaluated in a prospective study.

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Use of a Modified Dosing Weight for Heparin Therapy in a Morbidly Obese Patient

Abstract: Further investigation is necessary to determine the optimal DW for UFH in morbidly obese patients presenting with acute thrombosis.

Cited by 18 publications

References 12 publications

Unfractionated Heparin Dosing for Venous Thromboembolism in Morbidly Obese Patients: Case Report and Review of the Literature

Unfractionated Heparin Dosing for Venous Thromboembolism in Morbidly Obese Patients: Case Report and Review of the Literature

Influence of Body Mass Index on the Activated Clotting Time Under Weight‐Based Heparin Dose

Delayed efficient anticoagulation with heparin in patients with a weight of 110 kg and more treated for acute coronary syndrome

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