A prospective, randomized comparison of the effects of inhaled sevoflurane anesthesia and propofol/ remifentanil intravenous anesthesia on salivary excretion during laryngeal microsurgery

BACKGROUND: One of the goals of anesthesia for laryngeal microsurgery is to provide a clear surgical view, and therefore anesthetics that produce less saliva are desirable. Sevoflurane inhalation anesthesia and total IV anesthesia with propofol/remifentanil are widely used for anesthesia during laryngeal microsurgery; however, few rigorous comparisons of the effects of sevoflurane and propofol/remifentanil on salivation have been performed. METHODS: Forty subjects undergoing laryngeal microsurgery were randomly assigned for sevoflurane or propofol/remifentanil anesthesia. We prospectively compared the salivary flow rates, compositions, the number of suction episodes required to clearly view the laryngeal lesions before the main procedures, and residual secretion volume after the procedure in both groups. RESULTS: The mean salivary excretion rate was significantly higher in the propofol/remifentanil group than in the sevoflurane group (0.53 ± 0.39 vs 0.28 ± 0.15 mL/min, P < 0.001). Before starting the main procedure, the number of suction episodes required to clearly view the laryngeal lesions was also higher in the propofol/remifentanil group (5.0 ± 2.3 vs 2.1 ± 1.5, P < 0.001). Mean residual secretion in the oral cavity and oropharynx after the procedure was greater in the propofol/remifentanil group (2.13 ± 0.59 vs 0.45 ± 0.32 mL, P < 0.001). In addition, a significant difference in chloride levels in collected secretion was noted (sevoflurane; 93 ± 19 vs propofol/remifentanil; 135 ± 58 U/L, P = 0.004). CONCLUSIONS: Salivary excretion under propofol/remifentanil anesthesia is greater than under sevoflurane anesthesia during laryngeal surgery.