Ketamine Plus Nitroglycerin Versus Ketamine as Adjuncts to Lidocaine for Intravenous Regional Anesthesia in Adult Patients Undergoing Hand Surgery

Abstract
Background: Different agents have been used as adjutants to lidocaine for intravenous regional anesthesia (IVRA) to improve the quality of analgesia.
Aim of the Study: The aim of this double blinded rand-omized controlled trial is to evaluate if adding nitroglycerin to ketamine is more effective than using ketamine alone as an adjuvant to lidocaine for IVRA.
Patients and Methods: Fifty adult ASA I-II patients undergoing hand surgery using IVRA were divided into two equal groups: ketamine/nitroglycerin (K/N) group received lidocaine 3mg/kg (maximum 200mg) with ketamine 0.1mg/kg (maximum 10mg) plus nitroglycerin 2mcg/kg (maximum 200mcg) and ketamine (K) group received lidocaine 3 mg/kg (maximum 200 mg) with ketamine 0.1mg/kg (maximum 10mg). Statistical analysis was done using Student's t test or Chi square analysis whenever appropriate.
Results: The two groups were similar in demographic data and patients characteristics. The onset times of sensory and motor blockades were significantly shorter in K/N group. Although the preoperative visual analogue scale for pain intensity (VAS) was comparable, the intra-operative and postoperative VAS, were significantly less in K/N group. The intra-operative fentanyl consumption as an intra-operative analgesia was significantly less in K/N group. Also, the time to call for the first postoperative analgesia was significantly longer in K/N group than K group. However the postoperative analgesics consumption showed no significant difference between the two groups.
Conclusion: In comparison to ketamine, adding a combi-nation of ketamine and nitroglycerin to lidocaine for IVRA improved the quality of anesthesia without inducing significant clinical side effects.