Comparison of the anesthetic effect of epidural lidocaine and tramadol and their combination in rabbit

Background and Objective: The aim of this research was to compare the anesthetic effect of epidural lidocaine and tramadol and their combination in rabbit as a model for further research on methods of epidural anesthesia in humans.

Materials and Methods: This experimental study was conducted on 12 New Zealand white rabbits that were divided into 3 groups of 4. In the first experimental group (L), 4 mg/kg of lidocaine 2% was used. For the second group (T), 4.4 mg/kg of tramadol was used. Third group (TL) received a combination of lidocaine (2 mg/kg) and tramadol (2.2 mg/kg). Sensory block, motor block, heart rate, respiratory rate and rectal temperature, 10 min before injection and at intervals of 10 minutes up to 90 minutes after injection was measured. SPSS statistical analysis software and paired sample t-test were used and significance level was p < 0.05).

Results: Based on obtained results, lidocaine group showed delayed onset of numbness and immobility (3±0.3 min) versus tramadol (1.25 ± 0.5 min) and tramadol+lidocaine (1 min) (p < 0.05). Also, the duration of numbness and immobility in tramadol group (7.13 ±5.2 min) significantly reduced as compared to the lidocaine+tramadol (20±1.14 min) and lidocaine groups (30±10 min) (p < 0.05).

Conclusion: In this study, lidocaine showed better results than tramadol and combination of lidocaine and tramadol as an epidural agent in rabbits.