Comparison of Caudal Vs Intravenous Tramadol Administered Either Preoperatively or Postoperatively for Pain Relief in Boys

Background: In this study we compared caudal with intravenous (i.v.) tramadol given pre- or postoperatively for pain relief in boys having hypospadias repair.

Methods: The study was approved by the Ethics Committee and informed written consent was obtained from the parents of each patient. Patients (n = 134), aged 1-3 years, American Society of Anesthesiologists (ASA) physical status I, scheduled for hypospadias surgery were recruited. The patients were randomly allocated to one of the four groups: group I (n = 33), received 2 mg.kg(-1) (0.5 ml.kg(-1)) of caudal tramadol after the surgical procedure was completed, group II (n = 33) received 2 mg.kg(-1) (0.5 ml.kg(-1)) of caudal tramadol before incision, group III (n = 34) received 2 mg.kg(-1) tramadol intravenously, after surgery and group IV (n = 34) received 2 mg.kg(-1) tramadol intravenously, after anaesthesia induction. When the patients were fully awake in the recovery area, heart rate, arterial pressure, peripheral oxygen saturation, respiratory rate, pain and sedation scores were recorded at 5, 10, 15, 30, 60 min, and 2, 3, 4, 6, 12 and 24 h postoperatively and side-effects were noted. Pain was assessed using an objective pain score (OPS).

Results: The OPS were lower in caudal tramadol groups than in i.v. tramadol groups only at 3 h (P < 0.05). The duration of postoperative analgesia was longer in the caudal groups than in the i.v. groups (P = 0.001). However, the duration of postoperative analgesia was unaffected by the timing of administration.

Conclusions: Caudal tramadol provides better and longer lasting postoperative analgesia than i.v. tramadol. These results also suggest that preoperative caudal tramadol did not provide any clinically perceptible benefits compared with postoperative caudal tramadol.