Evaluation of a Rat Cardiopulmonary Bypass Model Using an Extraluminal Flow Oxygenator

Area of Science:

• Cardiovascular Surgery
• Biomedical Engineering
• Animal Models

Background:

• Cardiopulmonary bypass (CPB) triggers systemic inflammation.
• Rat models are crucial for studying CPB mechanisms.
• Previous models used intraluminal oxygenators, limiting blood volume capacity.

Purpose of the Study:

• To evaluate a novel rat CPB model with an extraluminal flow oxygenator.
• To compare its performance against a CPB model with an intraluminal oxygenator.
• To assess hemodynamic stability, blood gas exchange, and inflammatory markers.

Main Methods:

• Developed a rat CPB model with an extraluminal flow oxygenator (0.0236 m² membrane area, 3.0 mL priming volume).
• Compared three groups: SHAM, CPB with intraluminal oxygenator (Int-oxy), and CPB with extraluminal oxygenator (Ext-oxy).
• Measured hemodynamics, blood gases, cell counts (RBC, WBC, PLT), and inflammatory cytokines (IL-6, IL-10, TNF-α) at baseline and post-CPB.

Main Results:

• Both CPB groups maintained stable hemodynamics (approx. 75 mmHg) and hemoglobin levels (9.5%) without transfusion.
• Effective oxygenation and CO2 removal were confirmed in both CPB models.
• The extraluminal oxygenator group (CPB Ext-oxy) showed significantly preserved platelet counts compared to the intraluminal group (CPB Int-oxy) at 60 and 120 minutes post-CPB initiation.
• No significant differences in IL-6, IL-10, or TNF-α levels were observed between the CPB groups.

Conclusions:

• The extraluminal flow oxygenator rat CPB model effectively simulates clinical CPB conditions.
• This model demonstrates improved preservation of platelet counts during CPB.
• It provides a valuable platform for investigating CPB-related biological responses and inflammatory mechanisms.