Comparison of lidocaine, lidocaine plus tramadol and lidocaine plus morphine in patients undergoing arm surgery for intravenous regional anesthesia comparison of ropivacaine, ropivacaine plus tramadol and ropivacaine plus morphine in patients undergoing minor hand surgery] comparison of anesthetic effect between 0.375% ropivacaine versus 0.5% lidocaine in forearm intravenous regional anesthesia.