Noncontact laser Doppler imaging in burn depth analysis of the extremities

The purpose of this study was to determine the accuracy and practical utility of a noncontact laser Doppler imager (PIM-II, Lisca Development AB, Linköping, Sweden) in the estimation of burn depth in the upper and lower extremities. At 48 hours after burn injury, we performed scans of 35 burns in 22 patients and obtained histological samples for burn determination with hematoxylin and eosin and vimentin immunohistochemical staining. Additionally, sequential scans and tissue specimens were obtained on 10 burns at 24, 48, and 72 hours. A statistically significant inverse relationship was noted between burn depth and the laser Doppler perfusion index. Laser Doppler perfusion index values greater than 1.3 predicted a superficial dermal burn with 95% sensitivity and 94% specificity. Superficial dermal burns exhibited increased perfusion in the early burn period. Wounds showed a progressive decline in perfusion and a progressive increase in the depth of injury during a 72-hour period. This study demonstrates the advantage and accuracy of using a noncontact laser Doppler to differentiate deep dermal from superficial partial thickness burns in the extremities.