Forearm versus upper arm tourniquet for intra venous regional anesthesia using lidocaine and magnesium

ABSTRACT

Intravenous regional anesthesia [IVRA] using a forearm tourniquet may be a safer technique than the traditional upper ann tourniquet. Also, addition of magnesium sulphate to lidocaine can offer better tourniquet tolerance and postoperative analgesia. This study was designed to compare the use of a forearm tourniquet versus traditional upper ann tourniquet and to evaluate the effects of adding magnesium sulphate to lidocaine in intravenous regional anesthesia. Sixty patients were allocated randomly into 4 groups. All groups received intravenous regional anesthesia [IVRA]. Group [UL] received 10 ml lidocaine 2%. Group [ULM] received 10 ml lidocaine 2% plus 15 ml magnesium sulphate 10%, both groups using upper arm tourniquet [UAT]. Group [FL] received 5 ml lidocaine 2%. Group [FLM] received 5 ml lidocaine 2% plus 7.5 ml magnesium sulphate 10%, both groups using a forearm tourniquet [FAT]. Results show that onset of sensory and· motor anesthesia occurred significantly earlier in forearm tourniquet groups compared to upper arm tourniquet groups. Also, onset of sensory and motor loss was hastened when magnesium was added to lidocaine compared non magnesium groups. Shortest times for complete sensory and motor blockade was in the forearm tourniquet group when magnesium was added to lidocaine. Pain scores were lower in forearm tourniquet groups than upper arm tourniquet groups, and were significantly lower when magnesium was added. Number of patients who asked for intraoperative fentanyl was significantly less in forearm tourniquet groups than in upper arm tourniquet groups; also it was significantly less with the addition of magnesium. Time to recovery of sensory blockade after tourniquet deflation was significantly prolonged in forearm tourniquet groups than upper arm tourniquet groups and was significantly prolonged with the addition of magnesium compared with non-magnesium groups. Motor blockade was also significantly prolonged after tourniquet deflation in forearm groups than upper arm groups; also it was more significantly prolonged in magnesium groups than in non-magnesium groups. First analgesic request was significantly delayed in forearm groups than upper arm groups, and more significantly prolonged in magnesium groups than in non-magnesium groups. No adverse events occurred in any of the 4 groups