Effectiveness of Continuous Veno-Venous Hemofiltration and Intermittent Hemodialysis in the Treatment of Severe Acute Phenobarbital Poisoning

Background: Phenobarbital poisoning is common in Vietnam. The aim of this study was to compare the effectiveness of continuous veno-venous hemofiltration (CVVH) and hemodialysis (HD) on clinical outcomes in the treatment of severe acute phenobarbital poisoning. Methods: This was a retrospective observational historically controlled study. 42 patients with severe phenobarbital poisoning were enrolled. 21 patients were treated with HD and 21 with CVVH. Both groups received similar supportive therapies consisting of mechanical ventilation, forced alkaline diuresis and multiple-dose activated charcoal. Results: Following one course of treatment with HD (4 hours) or CVVH (~19.5 hours) the mean (SD) blood phenobarbital concentration (BPC) had decreased to 3.9 (2.5) and 3.2 (2.3) mg/dL respectively (P=0.232). Mean percentage decrease in BPC after HD and CVVH were 62.7 (12.4) and 61.5 (22.0) % respectively, showing no significant difference (P=0.782). Mean duration of coma and mechanical ventilation in CVVH group was 31.9 (26.6) and 39.7 (27.9) hours, significantly shorter than those in HD group with 66.1 (32.5) and 66.7 (32.2) hours (P=0.002; 0.001) respectively. Conclusion: One course of treatment with CVVH and HD decreased the BPC to a similar extent but this was not associated with similar clinical outcomes. Although, CVVH was not associated with rapid fall in blood phenobarbital level, it clearly had clinical advantages by shortening the duration of coma and mechanical ventilation and with lack of coma recurrence in severe phenobarbital poisoning.