Anesthetic effects of adding intrathecal neostigmine or magnesium sulphate to bupivacaine in patients under lower extremities surgeries

BACKGROUND Regional anesthesia is widely used to perform different surgical procedures including those performed on the extremities. In this study, the anesthetic effects of adding intrathecal neostigmine or magnesium sulphate to bupivacaine in patients under lower extremities surgeries were assessed. MATERIALS AND METHODS In this double-blind randomized clinical trial, 90 patients, candidate for lower extremities surgeries in a training hospital, were recruited. The patients with ASA class I and II aging from 20 to 65 years between 2009 and 2010 were evaluated. The selected patients were randomly assigned to receive either bupivacaine alone (Group A, n=30), or bupivacaine plus magnesium sulphate 50% (Group B, n=30), or bupivacaine plus neostigmine (Group C, n=30). Then sensory and motor onset and complete block and the time of recovery were measured. RESULTS The sensory block onset time were 3.03 ± 0.981 in group A, 3.90 ± 2.71 in group B and 3.7 ± 1.08 in group C and knee flexion time were not significantly different among the three groups (P > 0.05), whereas the time to complete motor block was significantly longer in group C and motor recovery time were significantly different between groups (P=0.001). CONCLUSIONS According to the obtained results, it may be concluded that magnesium sulphate is a safe and effective adjuvant for increasing the onset time of motor block.