Use of laser Doppler flowmetry for estimation of the depth of burns.

The trend for treatment of deep second degree burns and third degree burns is toward early excision and skin grafting. The ability to predict burn depth accurately as early as possible is important for early excision and skin grafting. This study, prospectively evaluated the ability of laser Doppler flow measurements, obtained within 72 hours after burn injury, to predict the depth of burn wounds. A Periflux system 4001 laser Doppler flowmeter was used to measure the cutaneous microflow circulation of 100 selected points of burn wounds on 44 inpatients and of 1680 selected points on 120 volunteers from March of 1993 to February of 1994. The mean value of superficial second degree burns checked by laser Doppler was 194.6 perfusion units (PU). The value of deep second degree burns was 59.7 PU, and the value of third degree burns was 5.1 PU. The mean normal cutaneous blood flow of 120 volunteers (control group) was between 4 and 9 PU, except on the head, neck, hand, and foot. Blood flow of more than 100 PU correctly predicted (90.2 percent of cases) a superficial second degree burn. Blood flow between 100 and 10 PU correctly predicted (96.2 percent of cases) a deep second degree dermal burn. That of less than 10 PU correctly predicted (100 percent of cases) a third degree burn. There was also a significant correlation between initial flow measurements and the depth of burn wounds. We conclude that laser Doppler flow measurements performed early after burn injury are useful in predicting the depth of burn wounds. Laser Doppler flowmetry has the advantage of being easy to use and noninvasive and of providing immediate results for early determination of burn depth. Laser Doppler flowmetry is useful in selecting patients for early excision and grafting of burn wounds.