Background
Posterior lumbar plexus block provides unilateral blockade and great hemodynamic stability. In this trial, the efficacy of addition of clonidine to bupivacaine used in lumbar plexus block (LPB) was evaluated.
Patients and methods
Sixty ASA I or II adult patients undergoing hip surgery, receiving general anesthesia, were randomly allocated to three equal sized groups, according to the technique of postoperative analgesia. In group A patients extubated when they met the standard extubation criteria. In group B, a mixed solution of 15 mL bupivacaine 0.5% and 15 mL normal saline 0.9% was injected through lumbar plexus block technique before extubation. In group C, 2.5 μg/ml clonidine was added to bupivacaine. Postoperative pain, sedation, hemodynamics, analgesic consumption, local anesthetic side effects and serum cortisol level were compared.
Results
There was a highly significant statistical difference between the three groups as regards the postoperative VAS scores ( < 0.001). In contrast to group A patients, VAS remained <50 mm till the 6th hour postoperatively in group B patients and till the 12th hour in group C with high significant difference in postoperative morphine consumption ( < 0.001). Hemodynamics and respiratory rate were in normal range 2 h postoperatively in the three groups. After the 6th hour postoperatively; SBP, DBP, HR and RR were significantly higher in group A patients in comparison to groups B and C ( < 0.05). In group C patients; SBP, DBP, HR and RR were in normal range for the first 12 h postoperatively. Blood cortisol level was higher then normal in group A patients since 2 h postoperatively (, 0.05), while started to rise from the 6th hour in group B patients and the 12th hour in group C patients.
Conclusion
The study showed that posterior lumbar plexus block was an effective postoperative analgesic technique in patients undergoing hip surgeries and that adding clonidine in a concentration of 2.5 μg/ml to bupivacaine 0.25% has resulted in decreasing the postoperative analgesic requirements.