The effect of LOW flow anesthesia on respiratory function tests with undergoing obesity surgery patients

After getting approval from the ethics committee ASA status II-III, between 18-65 years of age who were scheduled to undergo elective laparoscopic bariatric surgery were enrolled in the study. The patients were divided into two groups according to anesthesia flow as Low Flow Anesthesia (Group 1) and High Flow Anesthesia (Group 2) . After preoxygenation, 1-2mcq/kg fentanyl, 5-7 mg/kg thiopental was applied to the patients, and the muscle relaxation was achieved with 0.6 mg/kg rocuronium, and they were intubated orotracheally with an appropriate diameter intubation tube. As maintaining peroperative SAB ± 20 % in anesthesia management, gas flow was 4.5 l/min in first 10 minutes (50 % O2, 50% N2O) then 1 l/dk (% 50 O2,% 50 N2O) in Group 1 (n=25) and 4 l/min (50 % O2, 50 % N2O) in Group 2 (n=25). TGA was adjusted to 6 L / min at the end of anesthesia and the gases were switched to 100 % O2. Hemodynamic parameters, SpO2, ETCO2 were recorded intraoperatively at time intervals. Duration of surgery, eye opening times, extubation times, Modified Alderete Score ≥9, duration of anesthesia and were also calculated. These parameters were compared between group 1 and group 2. İn the preoperative, postoperative 2nd hour and 24th hour portable spirometry was used to measure PFTs and compared group1 with group 2. Group 1 and Group 2 were similar in terms of age, gender and BMI. There was no statistically significant difference between the groups in terms of intraoperative SAB, DAB, KTA,SpO2 and in the evaluation of the recovery period; extubation time, eye opening time Group 1 and Group 2. The ETCO2 was high at Group 1. There was a statistically significant difference in the Modified Aldrete Score ≥ 9, group 1 was seen to be lower. In terms of PFT parameters, FVC, FEV1, PEF, FEF 25-75 and FET values were statistically significantly decreased in the postoperative 2nd hour compared to the preoperative values. When the groups were compared, it was found that the significantly in group 1 than in group 2. Postoperatively at the 24th hour, FVC, FEV1, PEF and FEF 25-75 levels were increased compared to 2th hour. At FVC, FEV1, PEF and FEF 25-75 levels significant change were detected at the postoperatively 24th hour to preop levels but there were no significant differences between groups. The low-flow anesthesia affects PFT parameters less than high-flow anesthesia in bariatric surgery. Therefore, we believe that low flow anesthesia can be used safely for bariatric surgery in obese patients. Key Words: Low Flow Anesthesia, Bariatric Surgery, Respiratory Function Tests