Effect of surgery and cardiopulmonary bypass on indocyanine green pharmacokinetics

The pharmacokinetics of indocyanine green (ICG), a marker for hepatic blood flow (HBF), were studied at selected times during the initial 24-hour postoperative period in patients undergoing cardiac surgery with (n = 33) and without (n = 13) cardiopulmonary bypass. Cardiopulmonary bypass (CPB) caused a depression in ICG clearance and, by implication, HBF, reaching 48% of the pre-anesthetic and 60% of the pre-bypass values 2 hours post-CPB, returning to control values between 8 and 12 hours post-CPB. Similar decreases, although to a lesser extent, were seen in the non-CPB patients. Simulations with model compounds showed that these changes could produce clinically significant alterations in drug concentration-time profiles.