Pentobarbital Removal During Continuous Venovenous Hemofiltration: Case Report and Review of the Literature

Background: Renal replacement therapy may enhance the elimination of barbiturates. Pentobarbital clearance during continuous venovenous hemofiltration (CVVH) has not been described previously. We report a patient case involving the measurement of serial pentobarbital levels during CVVH and review relevant literature characterizing extracorporeal pentobarbital elimination. Methods: The following is a retrospective report of a previously healthy 26-year-old woman who sustained a severe traumatic brain injury (TBI) and required administration of pentobarbital on hospital day 0 for intracranial pressure (ICP) control. Given concern for interference with the patient’s ongoing neurologic assessments, pentobarbital was discontinued on hospital day 4. The patient’s hospital course was complicated by acute kidney injury (AKI), requiring initiation of CVVH on hospital day 5. Daily serum pentobarbital levels were obtained during CVVH. Results: While on CVVH, the patient’s estimated pentobarbital clearance ranged from 6 to 44 mL/min and the elimination half-life ranged from 17.7 to 65.9 hours. Based on reductions in pentobarbital clearance during CVVH interruption, the elimination of drug was dependent upon extracorporeal removal in this patient. CVVH facilitated pentobarbital elimination in a manner approaching endogenous clearance in healthy individuals. Conclusion: We report clinically significant pentobarbital removal by CVVH in a patient with severe TBI. Application of CVVH may expedite reliable neurologic assessments and facilitate the application of clinical brain death examination following pentobarbital exposure.