Propofol Requirement in Patients with Growth Hormone-Secreting Pituitary Tumors Undergoing Transsphenoidal Surgery

Growth hormone (GH) secretion is regulated by various hormones or neurotransmitters, including gamma-aminobutyric acid. The aim of this study was to determine the propofol requirement in patients with GH-secreting pituitary tumors undergoing transsphenoidal surgery. General anesthesia was induced in 60 patients with GH-secreting tumors (GH group, n = 30) or nonfunctioning pituitary tumors (NF group, n = 30) using an effect-site target-controlled intravenous propofol infusion. The effect-site concentrations were recorded at both a loss of consciousness and a bispectral index (BIS) of 40, along with the effect-site concentration after extubation, during emergence from the anesthesia. The effect-site concentration of propofol was higher in the GH group than in the NF group at a loss of consciousness and a BIS of 40 (4.09 +/- 0.81 vs. 3.58 +/- 0.67, p = 0.009 and 6.23 +/- 1.29 vs. 5.50 +/- 1.13, p = 0.025, respectively) and immediately after extubation (1.60 +/- 0.27 vs. 1.40 +/- 0.41, p = 0.046). The total doses of propofol and remifentanil during anesthesia were comparable between the groups (127.56 +/- 29.25 vs. 108.64 +/- 43.16 mu g/kg/min, p = 0.052 and 6.67 +/- 2.89 vs. 7.05 +/- 1.96 mu g/kg/h, p = 0.550, respectively). The propofol requirement for the induction of a loss of consciousness and the achievement of a BIS of 40 is increased during the induction of general anesthesia in patients with GH-secreting tumors.