Compare the effects of low flow and high flow desflurane anaesthesia techniques by control of BIS monitoring on hemodynamy and cost.

SUMMARYToday with the usage of modern anaesthesia machines, the interest for the low flowanaesthesia is continually rising due to its benefits such as decrease in consumption of vapour,decrease in cost and the increase in sensitivity of the humanbeing for the ecology. The aim ofthis study is to compare the effects of low flow and high flow desflurane anaesthesiatechniques by control of BIS monitoring on hemodynamy and cost.In this study 40 ASA I-II patients scheduled for septorinoplasty operation were selectedrandomly (Low flow group n=20, High flow group n=20). Intramuscular midazolam 0.1mg/kg was administered as premedication to all patients 1 hour before the operation. Systolicblood pressure, diastolic blood pressure, mean blood pressure, heart rate, oxygen saturationand bispectral index, end- tidal carbondioxide, inspired-expired desflurane parameters weremonitored. Patients demographic parameters (age, weight, ASA score, gender), anaesthesiaand operation durations were recorded. Anaesthesia induction was maintained for both groupswith; Na-thiopental 4-6 mg/kg, vecuronium 0,1 mg/kg and fentanyl 2 g/kg inravenously.After endotracheal intubation desflurane %4-8 was administered with fresh gas flow 4 L/min(2 L/min O2 and 2 L/min NO2) to obtain bispectral indeks between 40-60. With thearangements of tidal volume 8 mL/kg, ETCO2 30-40 mmHg, respiratory frequency 10breath/min, SpO2 %94-100, FiO2:0.5 controlled mechanical ventilation was applied. In thelow flow anaesthesia group fresh gas flow was decreased to 1 L/min from 4 L/min, 10minutes after induction. Systolic blood pressure, diastolic blood pressure, mean bloodpressure, heart rate, oxygen saturation when patient was taken to the operation room (control),with these parameters, end- tidal carbondioxide (mmHg), inspired- expired desfluraneconcentration (%) were recorded after 1 min from intubation and at 5th, 10th, 15th, 20th,25th, 30th, 40th, 50th, 60th, 70th, 80th 90th. minutes and as a last one after 1 min fromextubation. In the recovery room systolic blood pressure, diastolic blood pressure, mean bloodpressure, heart rate, oxygen saturation, Visual Numeric Scale and Aldrete Recovery Scoringsat the 5th, 15th, 30th. minutes after extubation were recorded. Dion formula was used for costcalculation. All calculations for all time intervals were made separately and then a mean valueof whole was taken. In respect of systolic-diastolic-mean blood pressure, heart rate, oxygensaturation, end-tidal carbondioxide parameters there were no significal differences betweenthe groups. The recovery was faster in the low flow group than those in the high flow group(ARS≥9: 15th min in low flow group, 30th min in high flow group) (p<0.05). Cost and theconsumption of volatil anaesthetic were calculated lower in low flow group (p<0.05).As a result hemodynamy was stable at low flow anaesthesia technique with desfluranewith a short time of recovery as well as economic with a low cost and consumption of volatileanaesthetics.