Enhanced brachial plexus blockade. Effect of pain and muscular exercises on the efficiency of brachial plexus blockade

Summary Three groups each of 20 patients scheduled to undergo operations on hand or forearm, received supraclavicular brachial plexus blocks with 25 ml lignocaine 1.5%. Patients in the control group did not suffer from pain and were not asked to do muscular exercise. Patients with acute trauma of the upper limb formed the pain group and showed significantly decreased latency for onset of analgesia, partial and complete muscle paralysis. Patients in the muscle exercise group were free of pain and were asked to do muscular exercise for 5 minutes after injection of the lignocaine. Onset of analgesia, partial and complete muscle paralysis was significantly more rapid than in both control and pain groups. Changes in the duration of block were not significant. It is concluded that pain and muscular exercise enhance the onset of brachial plexus blockade.