Effect of chronic obstructive pulmonary disease on washout time of sevoflurane anesthesia: a placebo controlled randomized trial
AuthorSeker, Ilknur Suidiye
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Background: Respiratory functions and gas exchange deteriorates in patients with COPD. In our study, we aimed to investigate if there is any relationship between the washout time of sevoflurane and chronic obstructive pulmonary disease (COPD). Method: Sixty patients, American Society of Anesthesiology (ASA) 1-3 status; aged between 18-60 years old who underwent general anesthesia for an operation were enrolled in our study. Patients were divided into two groups: Group N (non-COPD n = 33), group COPD (patients with COPD, n = 33). Two patients were excluded from the study, a total of 31 patients in Group COPD. Pre-operative respiratory function tests were performed and standard monitoring was provided in the operation room. Both groups received propofol 2 mg/kg, fentanyl 1.5-2 mcg/kg and rocuronium 0.6 mg/kg intravenously, and an oxygen-air mixture of 50%/50% with a tidal volume of 6 ml/kg (ideal body weight) and sevoflurane of 1 MAC. Remifentanil was administered at 0.05-0.1 mcg/ kg/min intravenously in the maintenance of anesthesia. All patients were monitored by an anesthesia machine until extubation. A sevoflurane vaporizer was closed at the end of the operation and the measurement time was started. FiO2, Fi(ins), Fi(exp) of sevorain, End-tidal CO2 were recorded during the operation and Fins (Sevo)/Fexp (Sevo) ratio, MAC1, MAC2, MAC3, MAC4, extubation times were recorded. Fi(ins)1: percentage of sevorain filiation in inspirium before closing 1 MAC vaporizer. Fi(exp)1: percentage of sevorain filiation in expirium before closing 1 MAC vaporizer. Fi(ins)2: percentage of sevorain filiation in inspirium after closing 0.1 MAC vaporizer. Fi(exp)2: percentage of sevorain filiation in expirium after closing 0.1 MAC vaporizer. Results: There was no significant relationship between the respiratory function tests of individuals with or without COPD and MAC1, MAC2, MAC3, MAC4 and extubation time (P > 0.05). The cut-off criterion for MAC4 was determined to be 210 seconds. Conclusion: Although there was no difference between the washout and extubation times of both groups, increased BMI and decreased intraoperative hemoglobin values should be carefully considered during anesthetic management in the COPD group.