Use of Continuous Venovenous Hemodiafiltration to Enhance the Elimination of Serum Pentobarbital before Diagnosis of Brain Death

Abstract

Continuous venovenous hemodiafiltration (CVVHDF) was used to eliminate pentobarbital from the blood of a 30-year-old potentially brain dead male patient with traumatic intracranial hemorrhage after a motorcycle accident. The Acute Physiology and Chronic Health Evaluation (APACHE) II score of hospital day 1 was 24, but by day 8 it was 36, when the patient was considered to be brain dead. To control seizures and reduce intracranial pressure, pentobarbital had been administered in a continuous flow (2,880 mg/day for 5 days). Coma can be induced by pentobarbital at a serum level of 1∼5 mg/dL. However, drug intoxication should be excluded from a brain death evaluation; therefore, the patient was not given any drug for approximately 88 hrs after ceasing pentobarbital in order for serum level to dip below 0.5 mg/dL (which is the hypnotic level). At 48 hours from CVVHDF, the pentobarbital level was close to the hypnotic level (0.1∼0.5 mg/dL). Before stopping, the serum level of pentobarbital was 3.89 mg/dL and between 48 and 72 hours from CVVHDF, 4 cycles of pentobarbital half-life elimination (0.24 mg/dL) could be measured. Therefore, we suggest that in case of potential brain dead patients who have been administered pentobarbital, CVVHDF can enhance the elimination of pentobarbital from the circulatory system and shorten the waiting time for a brain death evaluation.

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

“…14 Serum pentobarbital levels less than 5 mg/L are not expected to interfere with neurologic assessment or brain death examination. 11…”

“…Lee et al reported the case of a 30-year-old male patient who sustained TBI after a motorcycle accident. 11 Pentobarbital was administered to treat seizures and control ICPs. After discontinuation of pentobarbital, CVVHDF was initiated to expedite reliable neurologic assessments and hasten the potential application of a brain death examination.…”

“…The use of continuous venovenous hemodiafiltration (CVVHDF) to enhance pentobarbital elimination prior to brain death examination has been described elsewhere. 11 To our knowledge, pentobarbital clearance during continuous venovenous hemofiltration (CVVH) has not been reported previously. Herein, we describe a patient case in which serial serum pentobarbital levels allowed for characterization of drug removal during CVVH.…”

“…10 Where laboratory measurement is available, serum pentobarbital levels less than 5 mg/L are conducive to brain death examination. 11 Given the drug’s elimination half-life of up to 50 hours, brain death examination delays following pentobarbital administration may be substantial. 1…”