Comparative Evaluation of Volatile Anaesthetic Agents for Attenuation of Venous Cannulation Pain: A Prospective, Randomized Controlled Study.

INTRODUCTION: Topical application of volatile anaesthetic agents has been found to attenuate the response to a mechanical stimulus; however, this effect of volatile anaesthetic on perception of pain during venous cannulation is not known.

AIM: To compare the efficacy of topically administered volatile anaesthetic agents for attenuating venous cannulation pain.

MATERIALS AND METHODS: This prospective, randomized, placebo controlled and double blind study was conducted on 120 patients, aged 20-60years. They were of American Society of Anaesthesiologists (ASA) I or II physical status, of either sex, planned for elective surgeries. These patients were randomized into 4 groups, of 30 each. Equipotent doses of halothane (1ml), isoflurane (1.5ml), sevoflurane (2.7ml) and sterile water (2.5ml; Control) were topically administered on the volar surface of forearm wrapped with cotton and aluminium foil; venous cannulation was performed with 18G intravenous cannula after 30 min. These patients were assessed for the incidence and severity of pain upon venous cannulation {visual analog scale (VAS), 0-100mm; 0 = no pain and 100 = worst imaginable pain}. Data were analysed by one-way ANOVA, Chi-square test and Kruskal-Wallis test. The p<0.05 was considered as significant.

RESULTS: A significant reduction in the incidence of venous cannulation pain was observed in the halothane (79%) group as compared to control (100%; p<0.05), isoflurane (100%; p<0.05) and sevoflurane (100%; p<0.05) groups. The severity of venous cannulation pain as assessed by median (interquartile range, Q1-Q3). VAS scores was reduced in the halothane {10 (10-20); p<0.001}, isoflurane {20 (10-30); p<0.001} and sevoflurane {20 (20-30); p<0.001} groups as compared to the control group {40 (30-40)}; VAS score in the halothane group was significantly less as compared to isoflurane (p<0.05) and sevoflurane (p<0.05) groups.

CONCLUSION: Topical application of halothane is most effective in reducing incidence and severity of venous cannulation pain; however, topical application of isoflurane and sevoflurane decreases only the severity of venous cannulation pain.