Summary of Results
This systematic review and meta-analysis investigated the safety and efficacy of using various SADs in children and adolescents undergoing adenotonsillectomy when compared to ETT. A pooled analysis revealed that the incidence of laryngospasm was comparable with the use of either of the airway adjuncts, with a moderate level of evidence. The failure rate with SADs, i.e., conversion to ETT, was considerably high. The failure of the airway in the ETT group was zero because an ETT is a definitive airway and is unlikely to fail. The overall recovery time with the use of SAD was significantly less.
Airway management is of paramount importance in pediatric anesthesia [23,24]. This responsibility is even more crucial when the anesthesiologists are sharing the airway with the surgeons, as during adenotonsillectomies. These children have a higher propensity of having respiratory tract infections, mostly viral, and even if they do not have fever, the symptoms like cough and running nose are persistent. Such patients are more prone to perioperative respiratory adverse events (PRAE) like laryngospasm, bronchospasm, and desaturation [25].
The use of SADs in various pediatric surgeries became popular as it involves reduced airway stimulation, facilitates faster recovery, and leads to lesser hemodynamic changes, especially during intubation and extubation [26,27]. In a systematic review and meta-analysis investigating the safety and efficacy of LMA in pediatric laparoscopic hernia surgeries, Yang et al. concluded that the use of LMA is safe and leads to lesser anesthesia and recovery time and hence is an appropriate option when compared to ETT [28]. The use of a non-depolarizing muscle for placing LMA is not necessary and depends on the type of surgery and the comfort of the anesthesiologist [29,30]. However, Wu et al. suggested the use of non-depolarizing muscle relaxants can improve surgical conditions and reduce the incidence of adverse events like laryngospasm and bronchospasm [31].
Although several clinicians have started using SAD for various pediatric surgeries, its use in adenotonsillectomies is still considered controversial. Lalwani et al. retrospectively reviewed medical records of 1199 children who underwent adenotonsillectomy from 2003 to 2006, using both LMA and ETT [32]. On analysis, the authors concluded that the use of LMA for pediatric adenoidectomies is linked to a higher rate of complications, primarily from airway obstruction that occurs after LMA insertion or mouth gag placement. They also mentioned that in tonsillectomy, careful patient selection, insertion technique, and avoidance of controlled ventilation may reduce the risk of LMA failure. Surgeons’ ability to operate around the LMA may significantly impact the failure rate.
In a study involving 100 patients from 10 to 35 years undergoing adenotonsillectomy randomized for armored LMA and ETT as the definitive airway for surgery, the authors concluded that an armored laryngeal mask is reliable for performing adenotonsillectomy, provides adequate surgical access for adenotonsillectomy, and is also associated with a lower occurrence of respiratory adverse events like cough, bronchospasm and stridor at recovery. Patients with an armored LMA even demonstrated stable hemodynamics when compared to ETT [33].
In a prospective audit by Thorning et al. comprising 366 day-case pediatric ENT surgeries with LMA, the overall conversion from LMA to ETT was 4.3% (15 patients) [34]. Other than transient desaturation, the rest of the patients were successfully managed over an LMA. In a study comprising 139 pediatric patients (110 LMA, 27 with ETT, and 2 patients with LMA changed to ETT due to ventilatory difficulties) undergoing adenoidectomy, Boroda et al. attempted to investigate the success rate of LMA in these patients as an airway adjunct [35]. The authors concluded that the use of LMA is safe, without any significant adverse events, and also contributes to a reduced operating room time.
Gravningsbråten et al. reported their experience of 1126 pediatric patients (less than 16 years) undergoing office-based adenotonsillectomy using LMA [7]. In this series, one patient was reintubated because of atelectasis, and in six patients the LMA was replaced with ETT due to inadequate ventilation. Two patients underwent reoperation and eight patients were readmitted (two for reoperation and six for observation). They concluded that adenotonsillectomy can be safely performed in an office-based setting using LMA.
In another RCT involving 290 pediatric patients (less than 16 years) undergoing tonsillectomies, Ramgolam et al. compared the occurrence of perioperative respiratory adverse events during the emergence and post-anesthesia care unit phases of anesthesia [36]. On analysis, the authors concluded that there was no evidence for a difference in the timing of the LMA removal on the incidence of respiratory adverse events during the emergence and post-anesthesia care unit phases. However, in the post-anesthesia care unit solely, awake removal was associated with significantly more respiratory adverse events than deep removal. In a retrospective study comprising 179 pediatric patients who underwent adenotonsillectomy with LMA, Eguia et al. concluded that the use of LMA led to an overall reduced intraoperative time [37].
However, there was a study by Gehrke et al. in which the authors retrospectively analyzed pediatric adenotonsillectomy in around 1500 patients (683 in the LMA group and 849 in the ETT group) [38]. The authors reported that in at least 10 percent of cases, LMA was replaced with ETT and that the complications were more in the LMA group than ETT group. Based on the results of their study, the authors did not support the use of LMA as an airway device for pediatric adenotonsillectomies. The reason why the use of SGA is not used by several anesthesiologists is due to the fear of adverse events and also that the surgeons might find it difficult to operate with the SGA inside. However, the surgeons can be reassured about this, and in case of difficulty, an ETT can always be placed. The results of the meta-analysis also show that the incidence of respiratory adverse events is similar to SGA when compared to ETT.
The strength of this systematic review and meta-analysis is that only RCTs were included in the review. The overall heterogeneity of the studies included was low, but the level of evidence was moderate to low. The limitation was a relatively small number of studies can be analyzed. TSA confirmed that the postoperative recovery time was less with the use of SAD than with ETT. The SADs used were of different types in the included studies. Meta-analysis can be performed for three outcomes only as several outcomes were inconsistently reported.
