Continuous venovenous hemodiafiltration is the modality of choice for acute blood purification therapy at almost all medical institutions in Japan. Nafamostat mesilate, an ultrashort-acting anticoagulant, is widely used for anticoagulation. Due to restrictions imposed by national health insurance, Japanese institutions use an effluent flow rate of 15 mL/kg/h, which is lower than the standard effluent flow rate used in the West. In addition, hemofilters are believed to adsorb cytokines, and thus some institutions also proactively perform continuous renal replacement therapy with a hemofilter at an early stage for cytokine modulation in patients with sepsis. Although some aspects of these Japanese practices differ greatly from Western practices, there has not been much evidence to support current standard methods. Therefore, Japanese researchers must continue working to produce evidence for those methods, at least those that are widely used in Japan.

Phenobarbital overdose can cause coma and even death. The consciousness disturbance is often prolonged due to its long half-life. In this study, we investigated the efficacy of direct hemoperfusion (DHP) for the removal of phenobarbital by measuring the blood levels of phenobarbital. Methods: Study subjects included five patients with phenobarbital poisoning who were transferred to our hospital. Direct hemoperfusion was carried out in three of the five patients (six times in total), and the elimination rate was calculated by measuring the blood levels before and after DHP. Furthermore, the disappearance rate of phenobarbital without DHP was calculated in all five patients (seven times in total) for comparison with the elimination rate. Results: The elimination rate of phenobarbital with DHP was significantly higher than the disappearance rate without DHP． Conclusion: This study suggests that early introduction of DHP should be considered as a treatment option for phenobarbital poisoning.