Manual and target controlled methods comparison in minimal flow anesthesia with laringeal mask

Background: Fresh gas flow and anesthetic agent delivery can be maintained by the anesthesiologist manually or by automatic adjustments with a target-controlled method in low and minimal flow anesthesia. Target controlled method; it is a gas delivery mode in which the desired agent and oxygen values on the device are determined by the anesthesiologist and the agent and oxygen delivery is automatically adjusted by the system without the need for additional manual adjustments to reach the targeted levels. The aim of our study was to compare the manual controlled method of the target controlled method in minimal flow anesthesia with laryngeal mask. Materials and Methods: 82 patients who underwent general anesthesia with laryngeal mask for inguinal surgery under elective conditions were included in our study. Target and manual controlled methods in minimal flow anesthesia were compared in terms of the time to reach the target value, inhalation agent stability and gas consumption. In addition, it was also evaluated whether the target-controlled anesthesia method reduced the number of interventions to provide similar anesthetic depth and prevent hypoxia. Results: End tidal sevoflurane concentration showed less variability in target-controlled anesthesia compared to manual control. The time to reach the targeted minimal alveolar concentration in the manually controlled group was found to be significantly shorter than the target control group (77 seconds versus 120 seconds). More device interventions were required to maintain targeted oxygen and anesthetic agent concentrations in the manually controlled group (8 and 2 respectively, P < 0,001). Oxygen and air consumption were statistically significantly lower in the manually controlled group. There was no significant difference in sevoflurane consumption and awakening time. Conclusion: As a result of our study, we showed that the target-controlled method can be used safely with minimal flow anesthesia in laryngeal mask applications. The target-controlled method has greatly simplified the minimal-flow anesthesia management by requiring fewer interventions to the device to maintain sevoflurane and oxygen concentration within desired ranges and contributed positively to the anesthesia process. Keywords: Target control, Manual Control, Minimal Flow, Laryngeal Mask,