Alternatives to DEHP plasticizers for extracorporeal circulation equipments

Objectives: The most frequently used plasticizer for polyvinyl chloride (PVC) is Di-(2ethyl-hexyl)phthalate (DEHP). Several studies warned of using DEHP because it might cause hepatic, renal and reproductive complications, especially in newborns and male infants. Meanwhile, DEHP containing toys used for children below 2 years are prohibited. This study investigates the release of plasticizers by comparing medical grade PVC with several DEHP blocking surface coatings and PVC with the alternative plasticizer Tri-(2ethyl-hexyl)trimellitat (TEHTM). Material and Methods: Six groups of different PVC formulations were investigated in a well established Chandler-Loop model by using fresh whole blood, taken from healthy volunteers (n=6). The loops were formed out of test-tubes (50cm) from ordinary PVC tubes, PVC with blocking surface coatings and PVC with the plasticizer 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. Additionally, changes in coagulation, complement and blood cell alteration were measured to control the hemocompatibility. Results: Blood samples from the TEHTM plasticized PVC had less than 1% phthalate esters and metabolites compared to ordinary PVC (p<0.01). PVC tubings with different blocking coatings still released 14 to 73% DEHP of noncoated PVC. Conclusions: All DEHP containing PVC materials, even with blocking coatings cannot completely prevent leaching of the phthalate esters into the blood. Therefore, especially in critical patients, neonates or infants undergoing extracorporeal circulation procedures, the use of DEHP free PVC should be considered to diminish the toxic effects of DEHP exposure.