Comparison of Magnesium Sulfate and Paracetamol in Analgesic Effect and Venous Blood Gas Alterations during Intravenous Regional Anesthesia with Lidocaine

Intravenous regional anesthesia (IVRA) is an efficient method for short-term procedures of the upper extremities. Some defects are associated with IVRA including tourniquet-related pain and insufficient duration of the anesthesia. The main purpose of the current study was to compare the effects of adding paracetamol or magnesium sulfate to lidocaine in IVRA on pain، venous blood gasses (VBG) and sensory and motor block. There were 90 patients contributed in the current study. Patients were divided into paracetamol (P)، magnesium sulfate (Mg) and control (C) groups، randomly. Severity of the pain، time interval between the injection and onset of the sensory and motor block، duration of the sensory and motor block and the changes of VBG were measured. The onset of the sensory and motor block was reduced significantly in Mg group (p<0. 05). There was a meaningful increase in the motor block duration in Mg group in relation to C group (p<0. 05)، but no statistically significant difference between Mg and P groups. Also، there was no meaningful difference between C and P groups in the means of onset of block and block duration. Neither MgSO4 nor paracetamol decreased the tourniquet-related pain. The changes of VBG were significantly lesser in the P group. Adding MgSO4 to lidocaine improves the sensory and motor block in the IVRA. In other hand، paracetamol prevents ischemic changes to occur. None of these drugs are helpful to relief the tourniquet-related pain.