Effect of operation duration on pharmacokinetics of desflurane in patients undergoing tumor resection / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of operation duration on the pharmacokinetics of desflurane in the patients undergoing tumor resection.Methods:One hundred and fifty patients of both sexes, aged 18-75 yr, with body mass index of 19-25 kg/m 2, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, in whom abnormal preoperative lung function was not found, undergoing elective surgery with general anesthesia from November 2019 to March 2020, were enrolled in this study.Anesthesia was induced with intravenous injection of sufentanil 0.3 μg/kg, cisatracurium besylate 0.2 mg/kg and propofol 2 mg/kg.The patients were tracheally intubated after mechanical ventilation.Anesthesia was maintained with inhalation of desflurane, the vaporizer dial was adjusted to 6% with fresh gas flow rate of 2 L/min, and sufentanil and cisatracurium besylate were intermittently injected intravenously according to the changes in hemodynamics and degree of muscle relaxation during operation.The duration required for the end-tidal concentration of desflurane reaching 0.5 minimum alveolar concentration (MAC), time when the ratio of the end-tidal concentration of desflurane to the pre-set concentration of the vaporizer reached 1/2, time when the ratio of the end-tidal concentration of desflurane to the inhaled concentration reached 1/2, time for the end-tidal concentration of desflurane to decrease to 0.5 MAC and time for the end-tidal concentration to decrease from 0.5 MAC to 0.2 MAC immediately after closing the volatile tank were recorded.The patients were divided into 3 groups according to the operation time operation time <2 h group (group S), operation time 2-4 h group (group M), and operation time >4 h group (group L). Results:There were no significant differences among the 3 groups in the duration required for the end-tidal concentration of desflurane reaching 0.5 MAC, time when the ratio of the end-tidal concentration of desflurane to the pre-set concentration of the vaporizer reached 1/2, time when the ratio of the end-tidal concentration of desflurane to the inhaled concentration reached 1/2, time for the end-tidal concentration of desflurane to decrease to 0.5 MAC and time for the end-tidal concentration to decrease from 0.5 MAC to 0.2 MAC immediately after closing the vaporizer ( P>0.05). Conclusion:Operation duration does not affect the pharmacokinetics of desflurane in the patients undergoing tumor resection.