The use of topical anesthesia during intravenous catheter insertion in adults: a comparison of pain scores using LMX-4 versus placebo.

INTRODUCTION: Intravenous (IV) catheter placement is an extremely common painful procedure performed in all ages and healthcare settings, more often than not without anesthetics, despite clear research and guidelines demonstrating their effectiveness. This study examined differences in pain scores following topical anesthetic and placebo application, in a sample of healthy adult volunteers experiencing IV catheterization.

METHODS: During this prospective, placebo-controlled, double-blind study, 43 subjects were randomized to receive LMX-4 on one hand and hand cream on the other 30 minutes prior to IV catheterization. Paired t-tests were used to measure the difference in pain scores between hands. Pain scores were reported utilizing a visual analog scale (0-10 cm) immediately after each stick. As a control, the difficulty of the IV stick was rated on a 0-10 cm scale and recorded by the nurse who started the IV.

RESULTS: The mean pain score and standard deviation reported for the LMX-4 hand was 3.2 (SD=2.25, range, 0-8.5 cm), while the placebo hand was 4.67 (SD=2.25, range, 0.25-10 mm). The mean paired difference between LMX-4 and placebo hands was -1.37 (95% CI; -2.2, -0.49); subjects receiving LMX-4 reported clinically as well as statistically significant pain reductions (t=-3.17, p=0.003). When adjusted for difficulty of stick, pain scores continued to remain lower in the LMX-4 hand.

DISCUSSION: These findings suggest that the topical use of LMX-4 anesthetic cream is a viable option for reducing the pain associated with IV catheter insertion in adults.