Modified surface coatings and their effect on drug adsorption within the extracorporeal life support circuit

A recently completed study quantified the percent of fentanyl or morphine sulfate lost to uncoated polyvinylchloride (PVC) tubing or to one of two hollow fiber oxygenators within the extracorporeal life support (ECLS) circuit. The results demonstrated the majority of drug loss was due to adsorption by the PVC tubing. The purpose of this study was to determine if a tubing coating process affects fentanyl or morphine Sulfate adsorption. The goal was to quantify fentanyl or morphine sulfate lost due to adhesion within surface modified tubing. The following surface modifications were studied: 1) Maquet Safeline (synthetic immobilized albumin); 2) Maquet Softline (a heparin free biopassive polymer); 3) Maquet Bioline (recombinant human albumin + heparin) (Maquet Cardiopulmonary AG, Hirrlingen, Germany); 4) Terumo X Coating (poly2methoxylacrylate)) (Terumo Cardiovascular Systems Corporation, Ann Arbor, MI); 5) Medtronic Carmeda (covalently bonded heparin); and 6) Medtronic Trillium (covalently bonded heparin) (Medtronic, Minneapolis, MN). A total of 36 individual circuits were built from the above six available modified surface coatings, for a total of six individual circuits of each coating type. Blood samples were drawn at 5 minutes, 120 minutes, and 360 minutes followed by High-Performance Liquid Chromatography to determine available circulating levels of either fentanyl or morphine sulfate. Fentanyl concentrations decreased to an average final available concentration of 35% (+/- 5%) within the 18 circuits. Morphine sulfate however, decreased to a final available concentration of 57% (+ 1%) in all Maquet tubing and the Medtronic Trillium tubing, while it decreased to a final concentration of 35% (+ 1%) in the Medtronic Carmeda coated tubing and in the Terumo X Coating tubing. Biocompatible ECLS circuit surface coatings affected drug-adsorption and availability. Further evaluation is necessary to understand the adsorptive loss of other drugs administered to our patients while on modified surface coated ECLS circuits.