Pediatric patients who received treatment in Children's Hospital of Xuzhou Medical University (Xuzhou, China) from December 2016 to March 2018 were included. Clinical data, agitation index, anaesthesia recovery index, extubation time and PACU time were analyzed. Among those patients, 120 patients who received inhaled sevoflurane for pediatric anesthesia and intravenous infusion of propofol (2 mg/kg) were included in observation group. The remaining 80 patients who were directly anesthetized by sevoflurane alone were included in the control group. Pediatric Anesthesia Emergence Delirium (PAED), Aldrete scores, extubation time, PACU time and adverse reaction (gastrointestinal tract reaction) were compared between observation and control group, and PAED scores and Aldrete scores were recorded.

The present study was approved by the Ethics Committee of Children's Hospital of Xuzhou Medical University. Signed written informed consents were obtained from the parents of the child patients.

Inclusion criteria were: Patients who signed informed consent forms; who treated with ligation of inguinal hernia; without other severe diseases and with normal height, and weight. All patients were in American Society of Anesthesiologists (ASA) rate class I–II.

Exclusion criteria were: Patients combined with serious heart disease; with liver and kidney dysfunction; with dementia or mental disorders; allergic to propofol or sevoflurane and other drugs used in this study.

Atropine (national medicine permission no. H50020044, Southwest Pharmaceutical Co., Ltd., Chongqing, China); sevoflurane (national medicine permission no. H20080681, Nonan Bate Pharmaceuticals Co., Ltd., Linyi, China); dexamethasone 0.3 mg/kg (national medicine permission no. H41020056, Zhengzhou Zhuo Feng Pharmaceutical Co., Ltd., Zhengzhou, China); sodium chloride 0.9% (national medicine permission no. H37021756, Shandong Lu Chen Xin Pharmaceutical Co., Ltd., Shandong, China); propofol (national medicine permission no. H20051842, Guangdong Gabor Pharmaceutical Co., Ltd.); anesthesia monitor (General Electric Company, Boston, MA, USA).

Both groups of patients were not allowed to drink water 6 h before operation, and were not allowed to eat 4 h before operation. Intramuscular injection of atropine (0.01 mg/kg) was performed 30 min before operation. By setting a venous trocar, 4 ml dexamethasone (0.3 mg/kg) sodium chloride (0.9%) solution were injected through the indwelling needle. An anaesthesia monitor was used to monitor the vital signs of the children.

Intraoperative anesthesia: General anesthesia was performed with mask inhalation. Sevoflurane (8%) was first used to induce anaesthesia and the reactions of children's eyelashes and spontaneous breathing were observed. When there was no reaction of eyelashes but spontaneous breathing was maintained, the concentration of sevoflurane was reduced to 3–4% (adjusted according to the depth of the anaesthesia). Oxygen inhalation was kept at a speed of 2 l/min, and anesthesia was maintained until 5 min before the end of operation.

Post-operative treatment: Oxygen inhalation speed was raised to 6 l/min. Patients in observation group were intravenously injected with 2 mg/kg propofol, while patients in control group received intravenous drip of 0.1 ml/kg of normal saline. Monitoring blood pressure and other indexes of children was performed. After vital signs returned to normal, children were sent back to the ward.

PAED (9) mainly evaluates the conditions through 3 aspects: i) Whether they have eye contact with other people, ii) whether they can perceive changes in surrounding environment, and iii) whether they can dominate their own activities. The 3 items are reversely rated according to the severity, 4 points for none, 3 points for poor activity, 2 points for fair activity, 1 point for good activity and 0 point for excellent activity. The total scores is 20 points, the higher the scores is, the more serious the restlessness is; 11–15 points are evaluated as restlessness, and more than 15 points are evaluated as severe agitation.

Modified Aldrete scoring (10) were performed according to the standard shown in Table I. The total score is 10. Higher scores indicate better awakening situation. Patients with scores >9 points were extubated. Patients were monitored in recovery room for 15 min and were sent back to ICU if no abnormal conditions were observed.

Extubation time, time period from the end of the operation to the extubation; PACU time, from the time of the operation to the time of stay in the recovery room. Incidence of adverse reactions: Adverse reactions include mental stress, nausea and vomiting, gastrointestinal reactions, hypotension and arrhythmia.

The scoring results, extubation time, PACU time and other measurement data were recorded as mean ± standard deviation and compared by t-test. Incidence of adverse reactions was tested by χ². Correlation between PAED scores/modified Aldrete scores and extubation time/PACU time/incidence of adverse reactions was analyzed by Spearman's correlation coefficient. The significant level of the test was α=0.05.

There was no significant difference in age, weight, sex, operation time and classification of ASA between observation and control group (P>0.05) (Table II).

Mean PAED score of the control group was 9.87±3.15, and mean PAED score of the observation group was 5.66±1.74. PAED score of the observation group were significantly lower in observation group than those in control group (P<0.01; Fig. 1).

Mean modified Aldrete scores of the observation group was 7.91±2.14, which was significantly higher than that in control group (5.41±1.22) (P<0.01; Fig. 2).

Mean extubation time of observation group was 11.35±3.17 min, which was significantly lower than that of control group (21.41±4.62 min). PACU time of observation group was 46.57±7.43 min, which was significantly lower than that in control group (49.23±8.22 min). Incidence of adverse reactions in observation group was 5.00%, which was also significantly lower than that in control group (13.75%; P<05) (Table III).

PAED scores were positively correlated with extubation time, PACU time and incidence of adverse reactions (r=0.774, 0.689, 0.433). Modified Aldret scores were negatively correlated with PACU time and incidence of adverse reactions (r= − 0.821, − 0.769, − 0.524) (all P<0.05) (Table IV).