The main findings of this study were that safe management of anesthesia and shorter induction and recovery times with lower postoperative complications could be achieved with LMA.
A recent study [4] reported the safety of LMA in laparoscopic surgery among both adults and children. Our study indicated that induction and recovery times were significantly shorter in the LMA group; however, there were no significant differences in the duration of anesthesia or surgery between the two groups. Nevešćanin et al. [5] reported that LMA has the advantage of securing patients’ airways faster than ETT because a laryngoscope is not needed, and there is a higher rate of successful first attempts; these advantages suggested that induction was significantly shorter using LMA in our study. Our study indicated that LMA using a muscle relaxant proceeded to decrease recovery times compared to ETT. Although Ahiskalioglu et al. [6] reported that recovery times were significantly shorter for LMA without using a muscle relaxant, Tulgar et al. [4] reported that there was a significant difference between ETT and LMA using a muscle relaxant during recovery. Using a muscle relaxant was beneficial in terms of the clinical performance of LMA in pediatric patients under general anesthesia [4, 7]. Our study suggested that LMA may provide and maintain the same visibility as ETT to secure surgical safety and may shorten induction and recovery times using a muscle relaxant, in agreement with previous reports [4, 7]. Despite these results, ETT continues to be preferred over LMA owing to easier airway management and low risk of abdominal insufflation [4, 5].
Changes in hemodynamics were not significantly different between the LMA and ETT groups in our study. In previously reported adult laparoscopic surgeries, no significant changes in hemodynamic responses (HR and mean BP) between the LMA and ETT groups were observed [8]. Previous studies [3, 9] on general pediatric surgery reported that the hemodynamic responses were lower when using LMA. However, in pediatric laparoscopic surgery, our study was the first to compare hemodynamic responses between the LMA and ETT groups. In our study, although the HR and S/DBP were elevated in the LMA group, no significant differences in the changes in HR and S/DBP were observed between the LMA and ETT groups. This suggests that, although the elevation in HR and S/DBP in the LMA group was observed during LPEC, the changes in HR and S/DBP may be stable with either device. Thus, we suggest that elevation of hemodynamics with LMA could be permissive during LPEC.
BIS is a processed electroencephalographic parameter that quantifies the depth of anesthesia. It is represented by a number between 0 and 100, with 0 representing deep anesthesia and 100 indicating complete consciousness; the depth of general anesthesia and the depth of deep sedation are represented by BIS values of 40–60 and 60–70, respectively. Although BIS in pediatric anesthesia may be used to guide anesthetic administration in children > 2 years of age, BIS is not recommended for infants < 6 months of age [10, 11]. The age of the patients in the ETT and LMA groups were 65.0 ± 34.97 and 75.5 ± 27.74 months, respectively. Therefore, we believe that BIS was reliable for measuring the depth of anesthesia. The BIS values in our study ranged between 59.0 ± 6.77 and 65.5 ± 5.32 in the ETT group and between 60.4 ± 6.16 and 69.1 ± 4.35 in the LMA group. These results showed that the depth of anesthesia corresponded with deep sedation in the two groups. The change in BIS was 6.5 ± 3.51 and 8.8 ± 5.44 in the ETT and LMA groups, respectively; no significant difference was observed. These findings suggested that the same depth of anesthesia may be achieved with either device. Sinha et al. [11] reported that the removal of LMA during deep sedation (median BIS, 60; range, 58–76) reduced the prevalence of airway complications. Our finding that intraoperative BIS values between 60.4 ± 6.16 and 69.1 ± 4.35 corresponded with deep sedation may be a suitable indicator for the removal of LMA during LPEC owing to a low incidence of postoperative complications with LMA. Furthermore, our study suggests that during LPEC with LMA, the depth of anesthesia may be managed by deep sedation.
The maximum ETCO2 value and change in ETCO2 were significantly higher between the LMA and ETT groups in our study. Previous studies [3, 6, 8, 9] of general or laparoscopic surgery in adult or pediatric patients reported that no significant difference in the change in ETCO2 was observed between the two devices. Our findings were not consistent with the findings reported in previous studies. However, the maximum ETCO2 value in the LMA group was close to the upper normal limit of ETCO2. Thus, we supposed that the elevation in ETCO2 did not affect surgical performance and airway management, if the maximum ETCO2 value was close to the upper normal limit of ETCO2.
In our study, there was a greater incidence of postoperative complications, such as nausea and sore throat, with ETT. Additionally, previous studies [3, 8, 12] reported that ETT was associated with a greater incidence of sore throat (13.3–54.7%) than LMA; our finding was consistent with those of previous studies. In our study, we did not observe laryngospasm and aspiration in all cases; however, such complications were reported in previous studies [5, 8, 12].
Our study has two limitations. First, it was a retrospective comparative study. Second, the study was conducted in a single institution with a small study sample. However, the aim was to compare the duration of anesthesia and the changes in vital signs, ETCO2, and BIS, and postoperative complications. Additionally, the sample size was determined based on previous studies. Future studies with larger sample sizes are required to accurately determine the usefulness of LMA during LPEC in pediatric day surgery. While no previous reports compare changes in BIS achieved while using ETT versus LMA during LPEC, our study revealed that LMA was able to maintain the same quality and depth of anesthesia as ETT. Furthermore, while the use of LMA was equivalent to that of ETT with respect to the changes in hemodynamics and BIS, induction and recovery times were shorter when using LMA, with a low incidence of postoperative complications.