Clinical effects of dynamic cooling during pulsed laser treatment of port-wine stains

Pulsed dye lasers permit effective treatment of port-wine stains without a significant risk of complications. However, epidermal damage manifested by weeping or crusting of the treated area have been reported in 48-83% of patients, and transient hyperpigmentation after treatment is observed in 10-57%. Theoretically, the epidermis can be protected from thermal damage with the use of the concept of selective epidermal cooling. This study examined the clinical effects of rapid cooling of the epidermis with a liquid refrigerant R-134a (boiling point - 26.5 degrees C) during pulsed dye laser therapy. In 23 patients with port-wine stains, a 50-ms-long cooling pulse delivered immediately prior to laser irradiation with a fluence of 6.0J cm(-2) significantly reduced the pain, and shortened the period with purpura without; compromising the clinical blanching. Cooling periods longer than 60 ms, as well as additional cooling pulses immediately after laser exposure, reduced the blanching in areas irradiated with 6.0J cm(-2). Post-treatment hyperpigmentation was not prevented with dynamic cooling.