Tourniquet pain associated with intravenous region al anaesthesia is a common occurrence, despite adequate sensory blockade. The use of double tourniquets with in flation of the distal and deflation of the proximal cuffs, does not prevent the occurrence of pain. This pain might be due to direct ischaemic effects on the nerves or the sen sory innervation of the arteries due to local products of anaerobic metabolism. 50 patients, scheduled to undergo orthopaedic sur gery in the upper arm under local I. V. analgesia, were devided into two groups. Group I received 40 - 50 ml lidocaine at room temperature 24 -28 V & group II received the same valume oflidocaine at 4 -6V. The onset time of action of local anaesthetic was 4.7 0.9 min. & 5.9 1 min in group land group II respectively. Time to onset of tourniquet pain was significantly longer in group II (70.7 12.2 min.) than in group I (48.3 7.9 min.). This study has demonstrated that cooling of the local anaesthetic agent is simple, safe, and effective method in delaying the onset of tourniquet pain in upper extremity surgery. |
