Laser-assisted anesthesia prior to intravenous cannulation in volunteers: a randomized, controlled trial.

BACKGROUND: Intravenous cannulation is common and painful. Absorption of topical anesthetics is limited by the stratum corneum, the outermost layer of the epidermis. A single pulse of an erbium:yttrium-aluminum-garnet (Er:YAG) laser irradiation can remove an area of the stratum corneum, leading to enhanced uptake of topical agents, such as lidocaine, while leaving the rest of the epidermis intact.

OBJECTIVE: The authors hypothesized that pretreatment of the skin with laser-assisted anesthesia would reduce the pain of venous cannulation.

METHODS: This was a blinded, randomized, controlled clinical trial. Subjects were 30 healthy adult volunteers. Standardized venous cannulation was performed on the dorsum of both of each subject's hands. In the study hand, the area over the target vein was pretreated with a lightweight, portable Er:YAG unit, with a fluence of 3.5 J/cm(2), a pulse width of 600 microseconds, and a spot diameter of 6 mm. Lidocaine 4% cream was applied to the area. After 5 minutes, the cream was wiped off and a nurse inserted an intravenous (IV) catheter and verified placement. In the control hand, a sham laser was used. Pain of laser application and pain of IV cannulation were recorded on a validated 100-mm visual analog scale (VAS) marked "most pain" at the high end. The presence of burns, infection, and scarring at one week and at three months after the study was also noted. The levels of pain of cannulation were compared using a paired t-test.

RESULTS: Mean subject age was 32 years; 43% were female. The mean pain of cannulation after laser-assisted lidocaine application (13 mm, 95% CI = 8 to 19) was significantly less than after application of sham laser (29 mm, 95% CI = 22 to 36; mean difference, 15 mm, 95% CI = 6 to 24). No subject had persistent erythema or scarring.

CONCLUSIONS: Pretreatment of the skin with a laser device followed by a 5-minute topical lidocaine application reduces the pain of IV cannulation in volunteers.