Comparison of three different formulations of local anaesthetics for cervical epidural anaesthesia during thyroid surgery

BACKGROUND: To compare the efficacy and safety of local anaesthetics under cervical epidural anaesthesia (CEA) using lignocaine (1%), bupivacaine (0.25%) and ropivacaine (0.5%) for thyroid surgery. METHODS: In a prospective, randomized fashion, 81 patients were selected for thyroid surgery under CEA. They were assigned to one of three groups: Group L, B and R to receive 10 mL of 1% lignocaine, 0.25% bupivacaine and 0.5% ropivacaine, respectively. We compared their efficacy in terms of pulmonary and haemodynamic parameters, blockade quality and complications. RESULTS: Of the total, 74 patients completed the study successfully. Sensory block attained the median dermatomal range of C2-T4/T5 in all the groups. Motor block was more pronounced in the ropivacaine group. Cardiorespiratory parameters decreased significantly in all the groups; however, none of the patients had any major complications except for bradycardia in two patients. Among the measured variables, the decrease in heart rate and peak expiratory force was more in the lignocaine group while forced vital capacity and forced expiratory volume at 1 sec declined to a greater extent in the ropivacaine group. The lignocaine group required significantly more epidural top-ups compared with the other two groups. CONCLUSION: We conclude that cervical epidural route can be safely used for surgery on thyroid gland in patients with normal cardiorespiratory reserve, using either of local anaesthetics chosen for our study. Under the selected dose and concentrations, the decrease in cardiorespiratory parameters was lesser with bupivacaine.