Lipid hemodialysis versus charcoal hemoperfusion in imipramine poisoning

Previous experimental results have demonstrated the possibility of eliminating imipramine (14 C-IP) by hemodialysis. A simultaneous uptake of the substance by the polyvinyl chloride extracorporeal blood lines could be shown. Based on these results the imipramine absorption capacity of the blood lines and of the artificial kidney (Hollow Fiber Artificial Kidney, HFAK, Model 4) were studied. Imipramine (IP) absorption capacity of a usual blood-line set (arterial and venous, surface area 86,000 mm) was estimated to be 43 mg, and that of the HFAK to be 207 mg. Charcoal hemoperfusion (300 gm of coated activated coconut charcoal) eliminated more than 90% of IP from the blood within 3 hr if the initial IP blood concentration was 2 mg/ml. In comparison, lipid hemodialysis using 20% soybean oil as dialysate eliminated 95% of IP from the blood when the initial IP blood concentration was 1 mg/ml and 98% when the initial IP blood concentration was 2 mg/ml. In vivo studies on the elimination of IP by lipid (10%) hemodialysis demonstrated a substantial removal of the substance. Within 2 hr of treatment, 12% of the administered dose (75% of the LD50) was eliminated.