A randomized controlled study of the effects of adding ultra-low dose naloxone to lidocaine for intravenous regional anesthesia

Objective
This study was designed to evaluate the effect of adding ultra-low dose of naloxone as an adjuvant to lidocaine for intravenous regional anesthesia (IVRA).
Method
Forty patients undergoing elective short procedures in the upper limb were randomly and blindly divided into two groups of twenty patients each. Group L ( = 20) received 3 mg/kg of 2% lidocaine diluted with normal saline to 30 ml. Group LN ( = 20) received 3 mg/kg of 2% lidocaine and naloxone 100 ng (1 ml) diluted with normal saline to 30 ml. Onset and recovery time of sensory and motor block, intraoperative and post-operative pain were measured by visual analog score (VAS), and also intraoperative analgesic requirement, time of first requirement of diclofenac postoperatively, total amount of diclofenac needed in 24 h, patient’s satisfaction and surgeon’s satisfaction scores were measured.
Results
Recovery of sensory block was significantly longer in group LN (26.7 ± 2.8 min) compared to group L (16.3 ± 0.6 min); value (0.000). Also the recovery of motor block was significantly longer in group LN (19.1 ± 1.0 min) compared to group L (17.9 ± 1.2 min), value (0.002). Intraoperative fentanyl requirement was significantly less in group LN (15.8 ± 5.0 mcg) compared to group L (40.0 ± 10.5 mcg), value (0.000). 1st fentanyl requirement time was significantly longer in group LN (22.4 ± 3.1 min) than in group L (14.5 ± 6.1 min), value (0.000). Time of first analgesic requirement post-operative was longer in group LN (78.5 ± 6.8 min) compared to group L (40.5 ± 2.0 min), value (0.000). Total amount of diclofenac needed in 24 h was significantly less in group LN (57 ± 50 mg) compared to group L (120 ± 45 mg), value (0.000).
Conclusion
The addition of ultra-low-dose naloxone 100 ng to lidocaine for IVRA in upper limb surgery, prolonged the duration of sensory and motor block, and reduced tourniquet pain, as well as intraoperative and postoperative analgesic consumption.