Supraclavicular Brachial Plexus Block: Comparison of Varying Doses of Butorphanol Combined with Levobupivacaine – A Double-Blind Prospective Randomized Trial

BACKGROUND: The ideal dose of butorphanol for brachial plexus block is not well known. AIMS: This study was carried out to evaluate 1 mg and 2 mg of butorphanol added to 0.375% levobupivacaine, with regard to the duration of analgesia. Our study also sought to assess the onset and duration of sensorimotor blockade, hemodynamic effects, sedation, and adverse effects. SETTINGS AND DESIGN: This study was a prospective, randomized, double-blinded, and comparative study. METHODS: Eighty adult patients of either sex undergoing upper limb surgeries under supraclavicular brachial plexus block were randomly allocated into two groups. Group LB1 received 29 ml of 0.375% levobupivacaine plus 1 mg of butorphanol diluted in 1 ml of normal saline. Group LB2 received 29 ml of 0.375% levobupivacaine plus 2 mg of butorphanol diluted in 1 ml of normal saline. The onset and duration of sensorimotor blockade, level of sedation, duration of analgesia, and adverse effects were assessed. STATISTICAL ANALYSIS: The data were analyzed with Student's t-test and Chi-square test. RESULTS: The onset of sensory (P = 0.032) and motor block (P = 0.026) was earlier in Group LB2 than in Group LB1. The duration of analgesia was significantly prolonged in Group LB2 (643.55 ± 131.6 vs. 511.73 ± 128.6 min; P = 0.001). The incidence of sedation was observed in more number of patients in Group LB2 (P = 0.01). Furthermore, the incidence of nausea, vomiting, and pruritus were observed in more number of patients in Group LB2 (P < 0.05). CONCLUSION: Higher dose of butorphanol in brachial plexus block hastens the onset and prolongs the duration of sensorimotor blockade and analgesia but is associated with a higher incidence of sedation which requires intense monitoring.