Propranolol binding in plasma during cardiopulmonary bypass

Area of Science:

• Pharmacology
• Cardiovascular Surgery

Background:

• Propranolol is a beta-blocker commonly used in cardiovascular medicine.
• Plasma protein binding influences drug efficacy and distribution.
• Cardiopulmonary bypass (CPB) is a complex procedure involving physiological changes.

Purpose of the Study:

• To investigate the impact of cardiopulmonary bypass on the plasma protein binding of propranolol.
• To understand how CPB-induced changes affect the free fraction of propranolol.

Main Methods:

• Seven patients undergoing CPB were studied.
• Plasma samples were analyzed for propranolol free fraction before, during, and after CPB.
• Heparin and protamine administration effects were assessed.

Main Results:

• The free fraction of propranolol doubled after heparin administration (6.6% to 13.5%).
• Following CPB and protamine, the free fraction decreased significantly (13.4% to 8.7%).
• Further decrease in free fraction observed post-CPB (to 6.5%).

Conclusions:

• Cardiopulmonary bypass significantly alters propranolol's plasma binding.
• Changes in free fatty acids and hemodilution are key factors influencing propranolol free fraction during CPB.
• These alterations impact the amount of propranolol available for therapeutic effect.