Effects of Anesthesia and Surgery on Plasma Endothelin Levels

Abstract

To investigate the clinical significance of endothelin (ET), a potent and long-acting vasoconstrictor peptide in anesthesia and surgery, we measured plasma ET-like immunoreactivity (ET-LI) levels by using radioimmunoassay in patients undergoing various kinds of surgery under general anesthesia. No significant changes in plasma ET-LI levels were observed in patients undergoing relatively minor surgery under general anesthesia with nitrous oxide and halothane (n=6), enflurane (n=6), or isoflurane (n=5). Although plasma ET-LI levels after surgery in patients undergoing total knee replacement (12.4 +/- 0.9 [mean +/- SEM] pg/mL, n=7), hysterectomy (11.4 +/- 0.6 pg/mL, n=8) or cholecystectomy (14.8 +/- 1.2 pg/mL, n=9) were no different from those before surgery, plasma ET-LI levels after surgery in patients undergoing gastrectomy (20.4 +/- 1.9 pg/mL, n=15), esophagectomy (24.7 +/- 2.5 pg/mL, n=12), hepatectomy (27.5 +/- 3.4 pg/mL, n=12), or heart surgery (43.1 +/- 4.1 pg/mL, n=18) were higher than those before surgery (P < 0.05). Changes in plasma ET-LI levels during surgery had positive correlations with the duration of the operation (n=100, r=0.51, P < 0.01) and intraoperative blood loss (n=100, r=0.30, P < 0.01). In patients undergoing subtotal esophagectomy, the plasma ET-LI level did not increase during the initial 2 h, but increased gradually during surgery, reached a peak within a few hours after surgery, and declined slowly thereafter. These results demonstrate that the plasma ET level increases gradually during major surgery, whereas it does not during anesthesia and minor surgery, and plasma ET level varies with blood loss and duration of operation. (Anesth Analg 1995;80:449-53)