Optimum time of LMA ProSeal removal in adult patients undergoing isoflurane anesthesia: A randomized controlled trial

Background and Aims: Optimum timing of laryngeal mask airway (LMA) removal after general anesthesia with isoflurane is debatable. The objective was to investigate the potential benefits of removing LMA ProSeal at <= 0.4 Minimum alveolar concentration (MAC) isoflurane over awake and "deep plane" extubation after short duration laparoscopic gynecological surgery. Material and Methods: In this prospective randomized trial 90 adult female patients undergoing elective laparoscopic surgery under general anesthesia using LMA ProSeal (TM) as airway device were included. At the end of surgery, LMA ProSeal (TM) was removed when the patient was awake, could open mouth following verbal command (Group A); at MAC <= 0.4 (Group B); or at MAC of 0.6 (Group C). Adverse airway events like nausea, vomiting, airway obstruction, coughing, bucking, laryngospasm were noted. Statistical analyses were done by SPSS statistical software (IBM SPSS Statistics for Mac OS X, Version 21.0. IBM Corp, Armonk, NY). Results: Baseline demographic characteristics were comparable in all three groups. Coughing or bucking at the time of LMA removal was higher in group A (P = 0.004). Snoring and airway obstruction after LMA removal was significantly higher in group C compared to group A and group B (P = 0.002 and P = 0.011, respectively). There was significant change in mean arterial pressure and heart rate between before and after LMA removal on group A (P = 0.008 and P < 0.001, respectively) but not in other groups. Conclusion: MAC <= 0.4 can be considered optimum depth of anesthesia for removal of LMA Proseal in adult patients undergoing isoflurane anesthesia.