[Changes in endothelin in plasma in patients undergoing coronary artery bypass grafting under high dose fentanyl...

We measured plasma endothelin-1 (ET) in 10 patients undergoing coronary artery bypass grafting under high dose fentanyl (107.0 +/- 11.9 micrograms.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. ET levels were analyzed by radioimmunoassay based on double antibody method using Silica ODS suspension. ET concentrations in period 1, 2, and 3 were 1.8 +/- 0.7, 3.4 +/- 1.1 and 3.1 +/- 1.3 pg.ml-1 (mean +/- SD), respectively. There were significant differences between the control value and the values obtained at periods 2 and 3 (P less than 0.05). The elevation in ET level before CPB suggests the existence of hidden coronary ischemia despite the absence of detectable sign indicating myocardial oxygen supply demand imbalance. It was also suggested that, under high dose fentanyl anesthesia, stress evoked by CPB might not affect plasma ET concentration.