The study testified that nasal spray esketamine could not only reduce preoperative separation anxiety but also decreased the high incidence of postoperative emergence agitation in preschoolers underwent general anesthesia with sevoflurane for strabismus surgery. Moreover, the advantage of esketamine are that the nasal spray is easy to be been accepted by the children and action quickly. There are no side effects such as respiratory depression and prolonged PACU staying time.
Preschool children were emotionally vulnerable and highly depended on their parents, so when separated from parents they often show anxiety, fear and even crying refused to separate [2, 12].Children with preoperative adverse separation memory will affect the implementation of the anesthesia induction and the quality of anesthesia leading to emergence agitation [13, 14], more serious may cause mental trauma, fear, urinary incontinence, depression, anxiety and other sequelae. So it is very important meaningful to reduce the separation anxiety before anesthesia in children undergo strabismus surgery. Preoperative psychological intervention and non-drug measures can ease some children with the separation anxiety rate, but preoperative medication is still is the most effective way to relieve patients preoperative separation anxiety.
Esketamine, a dextral ketamine isomers is now available in China.It has twice the anesthetic potency of racemic ketamineand produces less psychomimetic side effects than racemic ketamine .Because awake children are more likely to receive nasal spray, so we used nasal spray esketamine in the present study. Moreover, the benzene ring structure of esketamine enhances its fat solubility. After nasal spray administration, it is easy to penetrate the cell membrane of nasal mucosa, and the onset time is fast. In this experiment, it is observed that the onset time is 5–10 minutes after nasal spray, which is faster than that before dexmedetomidine surgery reported by Cimen ZS .
Strabismus surgery is a short surgery with little stimulation but needs meticulous operation ,therefore, the anesthesia for pediatric strabismus surgery requires absolute braking and appropriate analgesia. Sevoflurane inhalation anesthesia induction and laryngeal mask to maintain spontaneous breathing is a very suitable anesthesia scheme for pediatric strabismus surgery. Sevoflurane inhalation anesthesia induction and maintenance is widely used in pediatric anesthesia, because sevoflurane can retain the patient's spontaneous breathing, the induction of recovery is fast and controllable[19–20]. Although sevoflurane does not stimulate the respiratory tract, many children still often resist sevoflurane mask induction due to the unpleasant smell. Moreover,the unpleasant experience induced by anesthesia induction has been demonstrated to impact on postoperative emergence agitation when waking up.Therefore, it is necessary to give appropriate sedation before anesthesia induction . In the our study, we found that esketamine nasal spray provided adequate sedation effect for pediatric patients undergoing inhalational mask induction, and nasal spray esketamine (0.5 or 1 mg/kg) significantly reduced the mask scores as compared with group C. The quality of anesthesia induction was improved.
Postoperative emergence agitation is very common in children under sevoflurane general anesthesia, and the incidence of ophthalmic surgery is higher . Postoperative pain is often considered to be one of the main causes of postoperative agitation ; however, due to less surgical stimulation and the application of local anesthetics, the severity of postoperative pain after strabismus surgery is relative low, and the VAS score is 1 to 2 . There was no difference in CHEOPS scores among 3 groups in our study. We speculate that the main causes of postoperative emergence agitation are the use of sevoflurane and postoperative visual field occlusion. Previous studies have reported, a single dose or continuous infusion of ketamine has been shown to reduce emergence agitation after sevoflurane in children. Interestingly, we found that a single dose of esketamine spay prior to induction can also suppress postoperative emergence agitation without prolonging emergence time.
Furthermore, we found that 0.5 or 1mg/kg nasal spray of esketamine has no respiratory depression and can be safely used for preoperative sedation in children. We observed that the whole course of blood oxygen in the three groups was more than 97%. There are some limitations in our study. No midazolam or dexmedetomidine group was established to compare the effects with esketamine in preschoolers.
In conclusion, nasal spray esketamine 0.5 or 1mg/kg significantly reduced separation anxiety and also decreased the incidence of postoperative emergence agitation in children undergoing general anesthesia with sevoflurane for strabismus surgery.