PMEA is a hydrophilic polymer coating with a unique design that minimizes the adsorption and denaturation of proteins and blood cells. This study compares thrombus resistance, blood path resistance, thrombocyte profile, and blood trauma of the PMEA coated Capiox membrane oxygenator (Terumo, Japan) vs. an uncoated version.
METHOD: Six calves (mean bodyweight: 75.3 +/- 4.5kg) were placed on cardiopulmonary bypass for 6 hours and randomly assigned to the coated or uncoated oxygenator, with a low heparinisation protocol (ACT > 180s).
RESULTS: Macroscopically, red staining was observed in all uncoated oxygenators, and in none of the coated ones. Inlet pressure was significantly higher in the uncoated group (at 1 h: 279 +/- 25 vs. 175 +/- 11mmHg, p < 0.01 and at 6h: 217 +/- 10 vs. 171(8mmHg, p < 0.01). Thrombocyte count values (corrected for hematocrit and normalized by prebypass values) were significantly higher in the coated group (at 1 h: 76 +/- 6 vs. 53 +/- 13%, p < 0.01 and at 6 h: 70 +/- 6 vs. 44 +/- 26%, p < 0.01). Plasma hemoglobin was below 100mg/L in both groups throughout the experiments.
CONCLUSIONS: When compared with uncoated oxygenator, PMEA coated oxygenator exhibited increased thrombus resistance with lower inlet pressure and lower thrombocyte consumption. In both groups, trauma to red cells was minimal, emphasizing the efficient design of this type of oxygenator.