Complement activation during cardiopulmonary bypass. Comparison of bubble and membrane oxygenators

Area of Science:

• Cardiovascular Surgery
• Immunology
• Biomaterials

Background:

• Cardiopulmonary bypass (CPB) is essential for cardiac surgery but can trigger inflammatory responses.
• Bubble oxygenators are known to activate the complement system and lead to leukocyte sequestration.
• The use of methylprednisolone or membrane oxygenators may mitigate these CPB-induced inflammatory effects.

Purpose of the Study:

• To compare the effects of bubble oxygenators (with and without methylprednisolone) and membrane oxygenators on complement activation and leukocyte sequestration during CPB.
• To evaluate the efficacy of methylprednisolone sodium succinate in reducing CPB-induced inflammation.
• To assess the inflammatory potential of membrane oxygenators versus bubble oxygenators.

Main Methods:

• A prospective randomized trial was conducted with 91 patients undergoing CPB.
• Patients were divided into three groups: bubble oxygenator alone (Group I), bubble oxygenator with methylprednisolone (Group II), and membrane oxygenator (Group III).
• Complement activation (C3a, C5a) and transpulmonary leukocyte sequestration were measured.

Main Results:

• Group I showed a significant increase in C3a levels during and after CPB.
• Groups II and III exhibited significantly lower C3a levels compared to Group I.
• Transpulmonary leukocyte sequestration was significantly reduced in Groups II and III compared to Group I.

Conclusions:

• Bubble oxygenators alone induce significantly more C3a activation and leukocyte sequestration during CPB.
• Pre-treatment with methylprednisolone or the use of a membrane oxygenator significantly attenuates these inflammatory responses.
• These findings suggest that alternative strategies can mitigate CPB-associated inflammation in cardiac surgery.