Prophylactic unfractionated heparin and hemorrhage in neurocritically ill underweight patients: A case series and review of the literature
© American Society of Health-System Pharmacists 2020. All rights reserved. Purpose. Three cases of major bleeding associated with thromboprophylactic unfractionated heparin (UFH) therapy in underweight neurocritically ill patients are reported. Summary. Three underweight patients (body mass index of <18.5 kg/m2) were treated in the intensive care unit with major bleeds associated with UFH thromboprophylaxis. Two of the patients, a 76-year-old female and a 56-year-old female, had hemorrhages on presentation; the third patient, a 29-year-old male, developed bleeding during his admission. All 3 patients had past medical histories consisting of acute neurologic conditions within 6 weeks of presentation, including subdural hematoma, subarachnoid hemorrhage, and obstructive hydrocephalus secondary to a brain mass. All hemorrhages developed following the receipt of prophylactic UFH at doses of 5,000 units every 8 to 12 hours, which translated to high weight-based dosages (>300 units/kg/d). Additionally, hemorrhages were associated with prolonged activated partial thromboplastin time, which declined following heparin discontinuation. The major bleeds following UFH administration included an acute on chronic subdural hematoma, acute rectus sheath hematoma, and cerebellar hematoma. Stabilization of the subdural hematoma was achieved without the use of protamine and the patient was discharged in stable condition. The other 2 patients expired secondary to their hemorrhagic events. Naranjo nomogram scores for the patients indicated that heparin was the probable cause of bleed in 2 cases and a possible cause in 1 case. Conclusion. Three major hemorrhages developed following the administration of UFH. Underweight patients with neurologic injury may require increased clinical vigilance, reduced doses, and pharmacodynamic monitoring to improve safety outcomes associated with thromboprophylaxis.