Combined remifentanil/sevoflurane in paediatric tonsil surgery anesthesia: Effect on recovery time of respiration and consciousness in paediatric patients

Purpose: To evaluate the effectiveness of combined remifentanil/sevoflurane anesthesia on hemodynamic stability and postoperative recovery in paediatric tonsil surgery. Methods: In this prospective study, a total of 102 paediatric patients who underwent tonsil surgery in Taihe County People's Hospital between February 2021 and April 2022 were recruited and randomized at a ratio of 1:1 to receive either propofol alone (control group) or remifentanil plus sevoflurane (study group) during paediatric tonsil surgery, with 51 patients in each group. The anaesthetic effect of the two regimens was the primary endpoint and was evaluated by monitoring the mean arterial pressure (MAP), heart rate (HR) and oxygen saturation (SpO 2 ) levels of the patients before anaesthesia (T0), immediately after intubation (T1), at the beginning of surgery (T2) and at extubation (T3). Results: Remifentanil plus sevoflurane resulted in more stable MAP and HR of patients at T1, T2 and T3 than propofol alone (p < 0.05). Furthermore, patients in the two groups exhibited similar SpO 2 levels at T0, T1, T2 and T3 (p > 0.05). Conclusion: The combined use of remifentanil and sevoflurane anaesthetics is effective in paediatric patients undergoing tonsil surgery and thus may offer a viable alternative for such clinical practice. The drug combination maintains intraoperative haemodynamic stability in patients, boosts postoperative recovery, and lowers the risk of postoperative adverse events.


INTRODUCTION
Paediatric tonsillar lesions are associated with recurrent high fever and sore throat, which result in a detrimental impact on the growth of children [1], and recent data have shown a rising prevalence of paediatric tonsillar lesions in China [2]. Minor tonsillar lesions are typically managed by anti-infective drugs, while the worsening of tonsillar lesions often necessitates surgical interventions to improve patient prognosis [3], such as tonsillectomy. However, tonsillectomy may compromise the respiratory function of the patient. Therefore, the postoperative recovery of spontaneous breathing and consciousness of patients serve as critical indicators of patient conditions [4]. Furthermore, anaesthesia for children demands more clinical attention compared to that of adults [5].
Sevoflurane is a recently developed inhalational anaesthetic drug that offers several benefits to the paediatric population, including low blood gas distribution coefficient and low irritation, resulting in a more rapid onset of action and better postoperative recovery [6]. Rifentanil, on the other hand, is a commonly used intravenous continuous anaesthetic with rapid onset of action and rapid metabolism [7]. Previous literature [8] has reported the excellent efficacy of combining sevoflurane with remifentanil in paediatric tonsillectomy.
The present study was performed to investigate the anesthetic effect of combined remifentanil/sevoflurane in paediatric tonsil surgery.

General information
A total of 102 paediatric patients who underwent paediatric tonsil surgery in Taihe County People's Hospital between February 2021 and April 2022 were recruited and randomised into a control group and a study group, with 51 patients in each group.

Ethical approval
The study was approved by the ethics committee of Taihe County People's (approval no. 2022-10). All procedures were conducted in accordance with the protocol of Helsinki Declaration [8].

Inclusion criteria
Children who were aged ≤12 years and underwent paediatric tonsil surgery in Taihe County People's Hospital, with ASA classification of grades I-II, and whose families were informed of the study and signed the informed consent were included.

Exclusion criteria
Children with contraindications to paediatric tonsil surgery or the used anaesthesics, serious organ diseases, co-morbid psychiatric disorders or related family history, or severe immunological disorders, and whose families rescinded their consent were excluded.

Administration of anaesthesia
The patients in both groups were nil by mouth before surgery and received atropine (Shanxi Tianyuan Pharmaceutical Co. Ltd, Nation Drug Administration no. H14021324) at a dose of 0.01 mg/kg through intramuscular injection 30 min before surgery. Intravenous access was established, oxygen was administered by mask, and the patient's intraoperative vital signs such as ECG, mean arterial pressure (MAP), heart rate (HR) and blood oxygen saturation (SpO2) were monitored.

Control group
The patients in the control group received propofol (Hebei Yipin Pharmaceutical Co., Ltd., Nation Drug Administration NO. H20093542) at a dose of 2 -3 mg/kg and cisatracurium besilate (Jiangsu Hengrui Pharmaceutical Co., Ltd., Nation Drug Administration NO. H20183042) at a dose of 0.1 mg/kg via intravenous injection. This was followed by induction of anaesthesia with remifentanil (Jiangsu Enhua Pharmaceutical Co., Ltd., Nation Drug Administration NO. H20143314) at a dose of 1 μg/kg, and tracheal intubation was performed. Intraoperatively, remifentanil at a dose of 0.25 μg/kg/min) and propofol at a dose of 100 μg/kg/min were administered for intraoperative anaesthetic maintenance.

Study group
The patients in the study group were given sevoflurane mixed with oxygen via mask inhalation, with the sevoflurane concentration being gradually increased from 1 to 3 % and at an oxygen flow rate of 4 L/min. After loss of consciousness, the patient was given remifentanil at a dose of 1 μg/kg and cisatracurium besilate at a dose of 0.1 mg/kg via slow intravenous drip. The patient was then intubated with conventional mechanical ventilation set at a frequency of 12 breath/min, a tidal volume of 8 mL/kg and a partial pressure of 35 -49 mmHg of end-expiratory carbon dioxide. Intraoperative inhalation of sevoflurane at 3 % and pumping of remifentanil at a dose of 0.25 μg/kg/min were continued. The concentration and pump speed were adjusted according to the depth of anaesthesia of the patient. At the end of the operation, sevoflurane inhalation and remifentanil pumping were discontinued.

Anaesthetic effect
Anaesthetic effect was evaluated based on the haemodynamic indexes of the patient at different surgical time points. The haemodynamic indexes evaluated included arterial pressure (MAP), heart rate (HR) and oxygen saturation (SpO2) levels before anaesthesia (T0), immediately after intubation (T1), at the beginning of surgery (T2) and at extubation (T3) in the two groups. The more stable the haemodynamic parameters at each time point, the better the anaesthetic outcome.

Post-operative related recovery indicators
The postoperative recovery indicators, including time-elapsed before postoperative recovery of spontaneous breathing, consciousness, and extubation, were recorded.

Adverse reactions
Adverse reactions in the patients due to anaesthetic drugs were nausea and vomiting, respiratory depression, restlessness and cardiac arrhythmias.

Satisfaction with treatment
A satisfaction questionnaire was developed by the hospital and given to the patient's family for satisfaction scoring. There were 20 questions on this form, and the child's family members scored each question out of 5 points, with a total score of <70 points indicating dissatisfied, 70-89 points indicating satisfied, and ≥90 points indicating highly satisfied.

Statistical analysis
All the data obtained in this study were collated and analysed using SPSS 22.0. Measurement data are expressed as mean ± standard deviation (SD) and compared using t-test, while count data are expressed as number/proportion of cases (%) and tested using χ². P < 0.05 indicates that the difference is statistically significant. GraphPad Prism 8 was used as the software for plotting the images.

General information
The two groups were well-balanced in terms of baseline patient profiles (p > 0.05), as shown in Table 1.

Haemodynamic index levels at different time points
Remifentanil plus sevoflurane resulted in more stable MAP and HR levels of patients at T1, T2 and T3 than propofol alone (p < 0.05). Furthermore, patients in the two groups exhibited similar oxygen saturation (SpO2) levels at T0, T1, T2 and T3 (p > 0.05). (Figure 1)

Levels of selected recovery indicators after surgery
As shown in Figure 2, the time-elapsed before postoperative recovery of spontaneous breathing, consciousness, and extubation were 6.84 ± 2.39, 8.92 ± 3.47, and 9.54 ± 3.18 for the control group and were 3.64 ± 1.72, 5.43 ± 2.51, and 6.81 ± 2.83 for the study group. Patients administered with remifentanil plus sevoflurane experienced significantly shorter time-elapsed before postoperative recovery of spontaneous breathing, consciousness, and extubation than those with propofol (p < 0.05).

Adverse reactions
The incidence of postoperative adverse reactions in the control group was 17.6 % (9 / 51),   Table 2.

Treatment satisfaction
The total treatment satisfaction in the control group was 82.4 % (42 / 51), comprising of 9 cases of dissatisfied, 27 cases of satisfied, and 15 cases of highly satisfied. The total treatment satisfaction of the study group was 98.0 % (50 / 51), comprising of 1 case of dissatisfied, 29 cases of satisfied and 21 cases of highly satisfied. The patients were more satisfied with the dual-drug anaesthesia regimen combining remifentanil with sevoflurane than single propofol (p < 0.05), as shown in Table 3.

DISCUSSION
Paediatric tonsillar lesions are associated with a high morbidity rate and usually require surgical interventions for improved prognosis [9]. Local anaesthesia has been used for tonsil surgery previously, but the outcome of local anaesthesia is compromised when applied in paediatric patients due to their young age and poor compliance [10].
General anaesthesia with tracheal intubation is recommended for managing paediatric tonsillar lesions in order to ensure the smooth performance of surgery and reduce the risk of adverse events in paediatric patients [11]. Proper selection of anaesthetic drugs and doses for paediatric patients is particularly critical. The clinical requirements for paediatric general anaesthesia are adequate analgesia, rapid onset of action and metabolism, preservation of physiological reflexes and minimal impact on circulatory and respiratory function [12]. Sevoflurane is a commonly used inhalation anaesthetic agent for induction and maintenance of anaesthesia during paediatric surgery due to its benefits such as low blood gas distribution coefficient, rapid induction of anaesthesia and postoperative recovery, easy adjustability of anaesthesia depth, and low respiratory tract irritation [13]. Furthermore, it distributes evenly across the alveolar mucosa and significantly improves the absorption efficiency, thereby stabilising the patient's intraoperative haemodynamic parameters [14]. Moreover, it does not increase the risk of postoperative respiratory complications [15].
Rifentanil is a clinical opioid agonist with a rapid onset of action, good analgesia and a unique metabolic profile that allows for sustained extrahepatic hydrolysis by non-specific esterases [16]. The elimination half-life of plasma concentrations after discontinuation is only 3 -5 min, which provides good circulatory stability, controllability and non-accumulation [17]. It has been observed that the metabolism, volume of drug distribution and clearance of remifentanil are negatively correlated with the age of the patient [18]. In this study, patients in the control group received propofol, while those in the study group were treated with remifentanil/sevoflurane. The results indicated better anaesthetic effects produced by remifentanil/sevoflurane than propofol alone. Patients administered with remifentanil plus sevoflurane experienced significantly shorter time-elapsed before postoperative recovery of spontaneous breathing, consciousness, and extubation than those with propofol. The results of this study were similar to those of previous studies [19,20]. This suggests that the dual drug regimen of remifentanil and sevoflurane was significantly better than propofol for general anaesthesia induction in paediatric patients undergoing tonsil surgery.
Furthermore, the incidence of postoperative adverse reactions in the study group was significantly lower than that in the control group. Also, treatment satisfaction in the study group was significantly better than that in the control group. These findings provide additional evidence that the use of both remifentanil and sevoflurane is a reliable method for maintaining the patient's respiratory and circulatory stability during paediatric tonsil surgery. This anesthetic regimen provides a quicker and safer recovery for the patient and reduces the risk of postoperative complications. Ultimately, this approach is likely to enhance the family's satisfaction with the clinical care received.

Administration
of combined remifentanil/sevoflurane anaesthesia is more effective than propofol anaesthesia in paediatric patients undergoing tonsil surgery. The combination facilitates the maintenance of intraoperative haemodynamic stability and postoperative recovery and reduces the risk of postoperative adverse events.

Acknowledgements
None provided.

Funding
None provided.

Ethical approval
None provided.

Availability of data and materials
The datasets used and/or analyzed during the current study are available from the correspon-ding author on reasonable request.