Diethylhexyl phthalate as a factor in blood transfusion and haemodialysis

Di-2-ethylhexyl phthalate (DEHP), the most frequently occurring plasticiser in medical equipment manufactured from polymers of vinyl chloride, forms about 40% w/w of tubes and containers used for storing blood and for haemodialysis. The plasticiser leaches out into liquids with lipid contents, although it is very sparingly soluble in purely aqueous solutions. On infusion of 2-3 1 of stored blood, up to 200 mg DEHP may be transferred to the patient, while much higher quantities may be given during dialysis, which is moreover often repeated frequently over long periods. The acute toxicity of DEHP is very low (greater than 20 g/kg as LD50 in rats), and the ester is rapidly metabolised to products which are excreted in the urine and bile; chronic toxicity from the levels of dosage obtaining is thus very improbable. Carcenogenicity has never been demonstrable in animals, while teratological effects are of a very low order. Serious acute results observed after transfusion of neonates have not been proved to be caused by DEHP, and might be ascribable to accompanying foreign substances. Atheroma in chronic dialysis subjects is still unexplained, but hepatitis probably caused by diethylphthalate from plastic was resolved when apparatus plasticised by DEHP alone was substituted. The benefits of DEHP appear vastly to outweigh any risks. The status of DEHP as environmental contaminant is noted.