The analgesic effect of paracetamol when added to lidocaine for intravenous regional anesthesia

Background: Intravenous regional anesthesia(IVRA) technique is easy, reliable and cost effective with a high success rate of 94–98%when used in short operative procedures of hand or forearm ( Mahmoud et al., 2015; Scott, 2014). Many adjuvant drugs have been added to local anesthetics, such as, NSAIDs, paracetamol, opioids and adrenergic receptor agonists. Objective: To evaluate the effect of paracetamol on sensory and motor block onset time, sensory and motor recovery and postoperative analgesia, when added to lidocaine in IV regional anesthesia (IVRA). Patient and methods: 60 patients were enrolled in simple randomized double blinded prospective clinical study in Baghdad in AlAlYarmouk teachinghospital from 1st of February 2016 to 1st of December 2016. They were ASA I and II patients with upper limb(forearm and hand)elective surgery the expected time of surgery was 20 – 60 min planned for intravenous regional anesthesia. The patients were divided into 3 groups; Group 1: patients received IVRA 40 ml of 0.5% lidocaine with normal saline, Group 2 :received IVRA 40ml 0.5% lidocainewith 300mg paracetamol, Group 3: received IVRA 40 ml of 0.5% lidocaine solution with normal saline with systemic 300 mg paracetamol. Results: There was no significant differences noted among the three groups regarding the age, sex, height, weight, BMI and VAS score. There were a significant differences in sensory block onset time between group 2 and group 1(more rapid sensory block onset time in group 2 as p value < 0.001) and between group 2 and 3(more rapid sensory block onset time in group 2 as p value was 0.023) and between group 1 and 3(more rapid sensory block onset time in group 3 as p value was 0.001). There was a significant differences regarding sensory recovery between group 2 and 1(prolonged sensory recovery in group 2 as p value < 0.001) and between group 2 and 3(prolonged sensory recovery in group 2 as p value < 0.001) but no difference between group 1 an 3 (as p value 0.994). There was a significant differences regarding motor block onset time, between group 2 and 1(more rapid motor block onset time in group 2 as p value < 0.001) and between group 2 and 3 (more rapid motor block onset time in group 2 as p value < 0.001) but no differences between group 1 and 3 as(p value 0.507). Also there was a significant differences regarding motor recovery between group 2 and 1(prolonged in group 2 as p value < 0.001) and between group 2 and 3 (prolonged in group 2 as p value < 0.001), but no differences between group 1 and 3 as (p value 0.088). There was no differences in VAS score among all groups as p value more than 0.05. There was a significant differences in the time for the first analgesic request between group 2 and 1(prolonged in group 2 as p value < 0.001) and between group 2 and 3(prolonged in group 2 as p value < 0.001) and between group 1 and 3(prolonged in group 3 as p value < 0.001). Conclusion: IVRA paracetmol cause a decrease in sensory block onset time, motor block onset time, and increase in motor and sensory recovery time with no change in VAS score postoperatively as compared with systemic paracetmol or lidocaine alone.