Blood trauma induced by clinically accepted oxygenators

Hemolysis remains one of the most serious problems during cardiopulmonary b ypass (CPB), extracorporeal membrane oxygenation (ECMO), and percutaneous c ardiopulmonary support (PCPS). However, the hemolytic characteristics assoc iated with oxygenators are not well defined. A specialized hemolysis test p rotocol for oxygenators was developed. A comparative study was performed fo llowing this protocol to determine the hemolytic characteristics of the cli nically available oxygenators during CPB; pressure drop measurements in the blood chamber were also performed. Four oxygenators (Medtronic Affinity, C obe Optima, Terumo Capiox SX25, and Bard Quantum) were evaluated. Fresh blo od from healthy Dexter calves anticoagulated with citrate phosphate dextros e adenine solution was used. The blood flow was fixed at 5 L/min, similar t o that used in CPB. The Normalized Index of Hemolysis for Oxygenators (NIHO ) has been modified according to the American Society of Testing and Materi als (ASTM) standards. The NIH value, which was obtained from the circuit wi thout an oxygenator, was subtracted from the primary NIH value, obtained fr om the circuit with an oxygenator to eliminate the effects of a centrifugal pump or other artifacts. The NIHO value was the lowest in the Affinity (0. 0116 +/- 0.0017) and increased from Affinity < Optima (0.0270 +/- 0.0038) < Capiox (0.0335 +/- 0.0028) < Quantum (0.0416 +/- 0.0015 g/100 L). The Opti ma and Capiox did not demonstrate a significant difference. in addition, th is NIHO value has a close relationship to the pressure drop. In conclusion, this new evaluation method is suitable to compare the biocompatibility per formance of different types of clinically available oxygenators for CPB usa ge.