Comparison of caudal ropivacaine, ropivacaine plus ketamine and ropivacaine plus tramadol administration for postoperative analgesia in children

Background: The aim of this study was to compare the effect of single-dose caudal ropivacaine, ropivacaine plus ketamine and ropivacaine plus tramadol in children for postoperative pain management. Methods: Following ethics committee approval and informed parental consent, 99 ASA PS I or 11 children, between 1 and 10 years of age, scheduled for elective inguinal hernia repair with general anaesthesia, were recruited. After induction of anaesthesia and placement of a laryngeal mask airway (LMA(TM)), the patients were randomly divided into three groups to receive either caudal ropivacaine alone (0.4%, 2 mg(.)kg(-1)) in group R (n = 32) or ropivacaine (0.2%, 1 mg(.)kg(-1)) plus ketamine (0.25 mg(.)kg(-1)) in group RK (n = 33) or ropivacaine (0.2%, 1 mg(.)kg(-1)) plus tramadol (1 mg(.)kg(-1)) in group RT (n = 34) with a total volume of 0.5 ml(.)kg(-1). Systemic blood pressure (SBP and DBP), heart rate (HR), peripheral O-2 saturation (SPO2), respiratory rate (RR), sedation and pain scores were recorded at 5, 10, 15 and 30 min, 1, 3, 4 and 6 h following recovery from anaesthesia. Pain was evaluated by Children's Hospital of Eastern Ontario Pain Scale, and sedation with a five-point sedation test. Results: No difference was found regarding age, weight and duration of operation between the groups (P > 0.05). No patient experienced hypotension, bradycardia or respiratory depression. Duration of analgesia was longer in group RT (1377 +/- 204 min) than group R (1006 +/- 506 min) (P = 0.001). In the tramadol group, fewer patients required supplementary analgesics in the first 24 h (P = 0.005). Sedation scores were below 2 in all groups. Incidence of postoperative nausea and vomiting was higher in group RT (eight patients) and group RK (seven patients) than group R (one patient, P = 0.032). Conclusions: Ropivacaine (0.4%), ropivacaine (0.2%) plus ketamine (0.25 mg(.)kg(-1)) and ropivacaine (0.2%) plus tramadol (0.5 mg(.)kg(-1)) provided sufficient analgesia in children, but the duration of analgesia was longer in the RT group.