Analysis of epidermal protection using cold air versus chilled sapphire window with water or gel during 810 nm diode laser application

Background and Objectives: Many cutaneous laser devices incorporate a temperature-based epidermal protection system to minimize surface damage while continuing to affect targeted tissue. The use of cold air is a new technique to aid in epidermal protection during the application of cutaneous lasers. This study investigates the efficacy of cold air versus chilled sapphire in regards to epidermal preservation when used with an 810 nm diode laser. Study Design/Material and Methods: White-haired pink piglets and dark-haired pigmented piglets were treated using the 810 nm diode laser in conjunction with either (1) no cryogen protection; (2) cold air alone; (3) chilled sapphire window alone; (4) cold air with water/gel; or (5) chilled sapphire window with water/gel. Laser fluence was varied by adjusting laser duration time while maintaining the intensity at 60 W. Biopsies were obtained from the sacrificed animals, stained with Masson's trichrome, and analyzed for extent of epidermal damage. Results: Among white-haired pink pigs, the cold air afforded the same degree of epidermal preservation as the chilled sapphire window. Epidermal protection was further enhanced with the addition of either gel or water. Among dark-haired pigmented pigs, the chilled sapphire window alone likewise provided significant epidermal protection, although the cold air alone did not. However, with the addition of water/gel, epidermal preservation was demonstrated in both. Conclusions: Cold air is an effective means in promoting epidermal preservation, though slightly inferior to the chilled sapphire window on darkly pigmented subjects. Combining either method with water or gel further enhances surface protection, enabling safe use of higher fluences. Lasers Surg. Med. 32:129-136, 2003. (C) 2003 Wiley-Liss, Inc.