Changes in plasma endothelin in patients undergoing cardiac valve replacement under high dose fentanyl anesthesia

We measured plasma endothelin (ET) in 11 patients undergoing cardiac valve replacement under high dose fentanyl (116.6 ± 15.4 μg · kg^-1, mean ± SD) anesthesia. Arterial blood samples were obtained: 1) before induction of anesthesia (control), 2) just before the start of cardiopulmonary bypass (CPB), and 3) just before the end of CPB. Endothelin levels were analyzed by radioimmunoassay based on double antibody method using Silica ODS suspension. ET concentrations in period 1, 2, and 3 were 3.0 ± 1.1, 4.2 ± 1.7 and 4.5 ± 1.8 pg · ml^-1 (mean ± SD), respectively. There were no significant differences among these three values (P < 0.05). The results suggest that under high dose fentanyl anesthesia, surgical stress including that of CPB might not affect ET concentration in plasma.