DEHP release from polyvinyl chloride is diminished by heparin-coating

Objectives: Di-(2-ethylhexyl) phthalate (DEHP) is the most commonly used plasticizer for polyvinyl chloride (PVC) and may cause hepatic, renal and reproductive complications. This study investigated the release of plasticizers by comparing medical grade PVC with and without heparin coating and PVC with TEHTM (No-DOP) instead of DEHP as an alternative plasticizer. Material and Methods: Twenty ml of heparinized whole blood (1 IU/ml), taken from healthy volunteers (n=6), were recirculated in a modified Chandler-Loop (30 rpm, 37°C) formed of test-tubes (50cm). Three groups were compared: non-coated and heparin-coated PVC tubes (Carmeda) out of the same production line, and PVC with tri-(2ethylhexyl)trimellitat=TEHTM (Rehau AG, Rehau, Germany). Quantitative analysis of DEHP, dibutyl phthalate (DBP) and their metabolites was performed by selected ion monitoring gas chromatography/mass spectrometry operating in negative ion chemical ionization mode. Changes in coagulation, complement and blood cell alteration factors were measured by ELISA methods. Results: High amounts of phthalate esters and metabolites were detected in sera from PVC (DEHP) loops. In comparison, the samples of the heparin-coated tubes showed only 4% of the DEHP and 20% of the MEHP concentrations (p<0.01), and, as expected, the samples from the PVC (TEHTM/No-Dop) showed less than 0,7% for both analysts. Conclusions: Heparin coating of PVC tubes results in a good protection against the release of the phthalate esters into the blood. Therefore, especially in critical patients or infants undergoing extracorporeal circulation procedures, the use of DEHP leaching PVC should be revised to diminish the toxic effects of DEHP exposure.