Air-handling capabilities of blood cardioplegia delivery systems in a simulated pediatric model

Blood cardioplegia delivery systems are employed in most pediatric open heart cases to arrest the heart and keep it preserved during aortic cross-clamping. They are also used as part of a modified ultrafiltration system at the end of cardiopulmonary bypass. We evaluated and compared the air-handling capabilities of different types of blood cardioplegia delivery devices. A simple circuit incorporating a cardiotomy reservoir, a roller pump, a cardioplegia test system, and two emboli detection and classification sensors were used to investigate the air-handling capabilities of the following cardioplegia delivery systems: GISH Vision, Maquet Plegiox, Medtronic Trillium MYOtherm XP, Sorin Group BCD Vanguard, Sorin Group CSC14, and Terumo Sarns Conducer and Bubble Trap. The 0.25-in. circuit was primed with 400mL of Lactated Ringer's. Outdated packed red blood cells were added to obtain a hematocrit of 24-28%. System pressure was maintained at 50mmHg. Air (0.1, 0.3, 0.5mL) was injected at a speed of 0.1mL/s into the circuit just after the pump head. Gaseous microemboli (GME) were measured prior to the cardioplegia system and after the device to evaluate the air-handling characteristics. The tests were run at 100, 200, and 400mL/min blood flow for both 4 and 37°C. There were no significant differences among the groups when comparing precardioplegia delivery system GME, thus demonstrating that all devices received the same amount of injected air. When comparing the groups for postcardioplegia delivery system GME, significant differences were noted especially at the 400mL/min blood flow rate. These results suggest that for the devices compared in this study, the Maquet Plegiox and the Medtronic Trillium MYOtherm XP eliminated GME the best.