Laser-assisted anesthesia reduces the pain of venous cannulation in children and adults: a randomized controlled trial.

OBJECTIVES: Application of topical anesthetics before intravenous (IV) cannulation is effective yet limited by delayed transdermal absorption. The authors evaluated a handheld laser device to enhance topical anesthetic absorption by ablating the stratum corneum, the major barrier to drug absorption through the skin. The hypothesis was that laser-assisted anesthesia would reduce the pain of IV cannulation in emergency department (ED) patients.

METHODS: This was a blinded, randomized, controlled trial. ED patients aged 1 year and older requiring nonemergent IV cannulation were included. Patients were randomized to pretreatment of the skin with laser or sham laser, and standardized venous cannulation was performed on the dorsum of the patients' hands or antecubital fossa. In the experimental group, the area over the target vein was pretreated with a lightweight, portable Er:YAG unit, with a fluence of 3.5 J/cm2, a pulse width of 600 microseconds, and a spot diameter of 6 mm. Lidocaine 4% cream was applied to the area immediately after laser application. Five minutes later, the cream was wiped off and a trained nurse inserted an IV catheter. In the control group, a sham laser and lidocaine were used. Pain of laser application and IV cannulation was recorded on age-appropriate pain scales; presence of infection or abnormal pigmentation was determined at one week. Pain of cannulation was compared using parametric and nonparametric tests.

RESULTS: Sixty-one patients were randomized to laser (30) and sham (31) pretreatment. Mean (+/- SD) age was 27 (+/- 21) years, 49% were female, and one half were children younger than 18 years. The mean pain of IV cannulation was significantly less (mean difference, 28.3 mm; 95% confidence interval = 17.9 to 38.7) in patients pretreated with the laser (10.0 mm; 95% confidence interval = 4.4 to 15.6) than with sham laser (38.3 mm; 95% confidence interval = 29.3 to 42.2). The difference in children was also significant. Application of the laser was painless in most patients. No patient developed infection or abnormal pigmentation.

CONCLUSIONS: Pretreatment of the skin with a laser device followed by a five-minute topical lidocaine 4% application reduces the pain of IV cannulation in ED adult and pediatric patients.