Elevated troponin I level with hemoglobin based oxygen carrying solutions (HBOCs) as a priming solution despite...

Area of Science:

• Cardiovascular Research
• Biomedical Engineering
• Hematology

Background:

• Hemoglobin-based oxygen-carrying solutions (HBOCs) are investigated as blood substitutes.
• HBOCs may serve as priming solutions for cardiopulmonary bypass (CPB).
• Elevated troponin levels are a concern with HBOC use, especially in patients with myocardial damage.

Purpose of the Study:

• To evaluate HBOCs as a priming solution for CPB in a canine model.
• To assess the impact of HBOC priming on hemodynamic parameters, myocardial oxygenation, and cardiac markers.

Main Methods:

• Mongrel dogs underwent cardiac arrest and CPB.
• HBOC was used as the priming solution in the study group (n=7), while Lactated Ringer's was used in the control group (n=7).
• Extreme hemodilution (>80% blood replacement with HBOC) was performed; hemodynamic parameters, coronary sinus flow, PO2, hematocrit, hemoglobin, and troponin I were measured.

Main Results:

• HBOC priming allowed CPB at significantly lower hematocrit (5.37% vs. 15%) but maintained higher hemoglobin levels (8.34 g/dL vs. 5.37 g/dL).
• Left atrial pressure and left ventricular end-diastolic pressure were lower in the HBOC group during CPB.
• Post-ischemic troponin I levels were significantly higher in the HBOC group (49.64 ng/mL vs. 28.33 ng/mL).

Conclusions:

• HBOC-based priming supports cardiopulmonary bypass at very low hematocrit, potentially preserving myocardium and ensuring adequate oxygen supply.
• The significant elevation in post-ischemic troponin I levels with HBOC use requires further investigation before widespread clinical application.