After obtaining our Institutional Ethics Committee approval of, parents of each child read and signed a informed consent form before enrolment in the study. We studied 80 children, ASA I, aged 5–10 years old, undergoing unilateral internal fixation for upper limb fractures. The exclusion criteria were bilateral upper limb surgery, previous history of allergy to local anaesthetics, neuromuscular disease, preoperative history of upper respiratory tract infection, coagulopathy and communication difficulties. All children were randomly divided into two groups: RS group (0.25% ropivacaine combined with 0.1µg/kg sufentanil)and R group (0.25% ropivacaine alone). The dosage of 0.25% ropivacaine administered in each group was 0.5ml/kg. A randomization protocol was created by a specific investigator using random number generator software. Information about the groups, to which the children had been randomized, was kept in prepared non-transparent envelopes. All patients, PACU nurses and postoperative follow-up personnel were blinded to group allocation.
Patients were given no premedication. They were monitored with electrocardiogram and pulse oximetry, and their blood pressure were measured non-invasively after arrivingat the operating room. After an intravenous infusion of saline 0.9% was established, the anaesthesia was induced with propofol 2 mg/kg. When the patient's consciousness disappeared, 6% sevoflurane was inhaled by the mask, and the oxygen flow was adjusted to 5 L/min. After loss of the eyelash reflex and jaw relaxation, a laryngeal mask was placed and fixed, preserving the patient's spontaneous breathing. The anesthesia was maintained using 3% sevoflurane. All patients underwent ultrasound-guided intermuscular groove brachial plexus block and were performed by the same experienced anesthetist. A 5–10 MHz line type ultrasound probe was selected to discern target nerves and surrounding anatomy. The probe was placed above the clavicle and the structures of the anterior medial scalenus and beaded brachial plexus was obtained on ultrasound images. A 21G puncture needle was selected and inserted into the plane along the long axis of the probe. The drug was administered when the tip of the needle was near the brachial plexus. No other opioids were used during the operation. When the patient's plaster was fixed at the end of the procedure, sevoflurane was stopped and inhaled with oxygen 5 L/min, and the laryngeal mask was removed and admitted to the PACU when the MAC decreased to 0.6. During surgery if HR or MAP increasesd more than 20% of the baseline value, sevoflurane concentration could be increased to deepen anesthesia. Atropine 0.01mg/kg or ephedrine 0.3mg/kg was given if the reduction of HR or MAP was greater than 20% of the baseline value. Postoperative agitation was assessed by the Ramsay Scale. Sedation with propofol 1 mg/kg if agitation occurred in PACU. Postoperative pain was measured by the FLACC score (Face, Legs, Activity, Cry, Consolability scale: Each item was 0 to 2 points, and the total score was 10 points. 0 was relatively comfortable, 1 ~ 3 was mild discomfort, 4 ~ 6 was moderate pain, 7 ~ 10 was severe pain). If the score was greater than 4, a treatment of 0.5mg/kg ketorolac tromethamine was given.
The primary outcome measures were the FLACC score at 2, 4, and 6 h after surgery and the duration of analgesia in each group. Secondary outcome measures were the changes in vital signs during surgery in each group, the incidence of postoperative agitation, the postoperative awake time and the duration of stay in PACU. All adverse events were recorded. The sample size was calculated based on our preliminary experiment that enrolled 10 cases in each group. The duration of analgesia was 341.7 ± 53.5 for RS group and 307.4 ± 50.6 for R group. Using standard sample size calculation formula to achieve a power of 0.8 at α = 0.05, there should be at least 36 patients included in each group to detect a significant difference. To account for any patient dropouts or missing data, we planned to enroll 40 patients per study group. SPSS 18.0 was used for statistical analysis. Measurement data were expressed as mean ± standard deviation and inter-group comparisons were used for Group t test. Count data were expressed as percentage and the chi-square test was used for the comparison between groups. P < 0.05 was considered statistically significant.