Evaluation of Ketamine as an Adjuvant to Lidocaine in Intravenous Regional Anesthesia for Upper Limb Surgery

Abstract
Background: Intravenous regional anesthesia (IVRA) is used in outpatient hand surgery as an easily applicable and cost-effective technique but tourniquet pain is a limitation. Ketamine in subanesthetic dose is used as an adjuvant to IVRA to improve analgesia and to impair tourniquet pain.
Aim of Study: Is to illustrate the effect of ketamine as adjuvant to lidocaine used for IVRA in patients undergoing upper limb surgery.
Patients and Methods: This double-blind randomized controlled study was carried out on 60 patient, ASA I and II, 20-40 years, scheduled for elective minor upper limb surgery. Patients were classified into 2 groups (30 each): Group I (IVRA with lidocaine only) received 3mg/kg lidocaine 0.5% diluted with saline to 40ml and group II (IVRA with lidocaine and ketamine) received 3mg/kg lidocaine0.5% plus 50mg ketamine diluted with saline to 40ml. MAP, HR and SpO2 were measured before, after tourniquet application, during the surgery every 15 minute, and every 30 minutes after deflating the tourniquet. Type & duration of the operation, onset & duration of sensory & motor block were measured. VAS was recorded at 1, 2, 3, 6, 12, 18 and 24h after operation, time of first rescue analgesia, total analgesic given and any undesirable side effects.
Results: Demographic data, duration of operation and hemodynamic changes (MAP, HR and SpO2) were comparable. Onset of sensory and motor block were shorter in Group II than in Group I, but the duration of sensory and motor block was prolonged. In Group II, first dose of IV analgesic was delayed and the amount of pethidine was significantly de-creased. VAS and severity of tourniquet pain in group II were significantly decreased.
Conclusion: Adding ketamine 50mg to lidocaine for IVRA has faster and prolonged sensory and motor block and delayed tourniquet pain with better quality of postoperative analgesia.