EA is a group of unpleasant symptoms after emerging from GA, Especially in children. A child who has severe EA tends to go on to develop POBC. The incidence of EA ranges up to 80%20 depending on multiple factors. The mechanism of EA is still unknown. Some hypotheses point out that anesthetics agents mainly inhibitory neurological impulse in various brain regions.21–23 Previous studies have found that multiple factors were associated with EA, including anesthesia technique (short-acting volatile anesthetic agents), age, race, post-operative pain, surgical type, preoperative anxiety, and child’s temperament.3, 6–9, 19 Another study reported that some factors such as behavior management, anesthetic techniques (TIVA, GARA), medications such as benzodiazepine, opioids, alpha 2-agonists, clonidine, gabapentin, melatonin, propofol and ketamine, prolonged emergence time and adequate pain control could reduce the incidence of EA.24
The correlation between clinical emergence time and the incidence of EA is still controversial. 25–27 This present study in which the average emergence time in the children who had EA and severe EA was significantly shorter than in the children who had no EA. While the clinical emergence time was correlated with EA, the association between processed-EEG emergence time and EA could not be found. The average processed-EEG emergence times in the groups diagnosed as EA and severe EA were 4.5 (± 4.7) minutes and 4.5 (± 5.1) minutes. (p-values = 0.231 and 0.304, respectively). However, the numbers of children diagnosed as EA and severe EA were quite low, which might have affected the statistical analysis. Other factors including age, ASA physical status and pain score were found to be significantly related to EA and severe EA, similar to previous studies.7–9, 19 ROC curve analysis showed the significant predictors of EA: ASA physical status, clinical emergence time, and pain. Focusing on pain evaluation, pain measurement in small children was focus on the patient’s behaviors. Regarding the evaluation of EA and pain, they share the same behavior parameters, such as restlessness, which could affect the outcomes.
The processed-EEG values, state entropy, had no correlation with EA, which could imply that the depth of anesthesia at the time of ceasing anesthesia did not affect EA. This result was compatible with a study by Frederick HJ et al. who found no link between depth of anesthesia and EA.28 A possible explanation for this result in the current study involves a limitation of the processed-EEG itself that has some delay interpretation compared with the raw EEG.29–32 So at the point that the investigator recorded the processed-EEG value, the real depth of anesthesia, as indicated by the raw EEG, may have been lighter, which could have affected the study results.
Previous studies reported the effect of parental presence on the day of surgery and during the induction period, which could reduce the child's preoperative anxiety level 33–35. Regarding the hospital's policy, parents were allowed to stay with their children since arrival at the preoperative holding area until starting induction at the operating room. However, there was no significant correlation found between the child's preoperative anxiety level and EA in this study. This study result was compatible with the study by Arai YC et al., which reported that parental presence without premedication did not show any effect on emergence behaviors.36
Interestingly, our study results showed that the child who had shorter EA duration tended to have separation anxiety at POD 1,3 and 7. Multiple factors can precipitate separation anxiety, including environment changes or loss that result in separation. The surgery itself aggravates separation anxiety symptoms.37 Kain et al. reported that the anxious child who has parental presence during anesthesia induction tended to have a lower anxiety scale compared with the calm patient.38, 39 The EA management protocol may explain this study's results in our institution. Regarding the protocol, the child who had EA might be treated with IV fentanyl or propofol. Some of them responded well with medication while their parents were still not available at that period. So there may have a possibility that the acute stress from EA without parental presents can cause separation anxiety. Further investigation needed to prove the hypothesis.
A significant correlation was found between the airway device removal technique and maladaptive eating behaviors, whereas there was no correlation found between the airway device removal technique and severe EA. During awake airway removal, a patient can move their head and neck and cough, which can lead to postoperative sore throat (POST).40 POST, in turn, can affect eating behaviors depending on its severity,41, 42 while EA usually happens after the patient wakes up from the anesthesia. There were two limitations to this outcome assessment. Firstly, this present study included the type of surgeries that could precipitate POST, dysphagia, and intraoral cavity wound, which could affect the child is eating behaviors. Secondly, in the telephone interview process, the investigator did not explore more rooted in the group of children who had abnormal eating behavior to rule out POST dysphagia and pain.
As mentioned earlier, the main limitation of this study was sample size was too small to determine some factors which could affect the incidence of EA and POBC. Further investigations need to be done. In this present study, Total opioids consumptions were not collected. As we know that opioid can help to reduce EA, this might affect the study results.