Efficacy of charcoal hemoperfusion in paraquat poisoning

We studied the efficiency of in vitro and in vivo charcoal hemoperfusion for the removal of paraquat. At a flow rate of 200 ml/min, 93-99% of paraquat in 4 L of solution (5, 10, 100 ppm) was removed in less than 160 min. The disappearance half-time was 16 min 10 sec. At 100 ml/min, it was 49 min 30 sec. Of 23 paraquat poisoning cases, 15 patients underwent hemoperfusion (HP) of which 10 died of respiratory failure within 28 days (7.6 +/- 2.9) and 5 survived without pulmonary complications. Of eight patients who did not receive HP, six died of respiratory failure within 97 days (33.4 +/- 18.8), even when their general condition was good upon admission. Two who vomited the ingested paraquat immediately survived without HP, and their paraquat concentration in urine was less than one ppm on admission. In one patient, whose paraquat concentration in blood was followed serially, 99% of the paraquat was removed from circulating blood by a single hemoperfusion. We conclude that charcoal hemoperfusion is effective for the removal of paraquat from blood in vivo and from solution in vitro. Hemoperfusion may also improve survival after paraquat ingestion, but further data are needed.