ABSTRACT
OBJECTIVE: The aim of this study was to investigate the potential confounding effects of four different types of ambient lighting on the results of Laser Doppler Imaging (LDI) of a standardized cutaneous injury model. METHODS: After applying a mechanical stimulus to the anterior forearm of a healthy volunteer and inducing a wheal and arteriolar flare (the Triple response), we used a Laser Doppler Line Scanner (LDLS) to image the forearm under four different types of ambient lighting: light-emitting-diode (LED), compact fluorescent lighting (CFL), halogen, daylight, and darkness as a control. A spectrometer was used to measure the intensity of light energy at 785 nm, the wavelength used by the scanner for measurement under each type of ambient lighting. RESULTS: Neither the LED nor CFL bulbs emitted detectable light energy at a wavelength of 785 nm. The color-based representation of arbitrary perfusion unit (APU) values of the Triple response measured by the scanner was similar between darkness, LED, and CFL light. Daylight emitted 2 mW at 785 nm, with a slight variation tending more towards lower APU values compared to darkness. Halogen lighting emitted 6 mW of light energy at 785 nm rendering the color-based representation impossible to interpret. CONCLUSIONS: Halogen lighting and daylight have the potential to confound results of LDI of cutaneous injuries whereas LED and CFL lighting did not. Any potential sources of daylight should be reduced and halogen lighting completely covered or turned off prior to wound imaging.
ABSTRACT
Laser Doppler imaging (LDI) has been increasingly used to predict pediatric burn wound outcome. A majority of these wounds are scald, contact, or flame burns. No study has specifically evaluated the use of LDI in pediatric friction burns. Our objective was to critically evaluate LDI assessment of pediatric friction burns to determine its predictive value with this mechanism of injury. We conducted a retrospective review of all LDI scans performed on pediatric friction burns during a 2-year period. We identified 36 patients with a mean age of 3.6 years (range, 19 months to 15 years). LDI accurately predicted burn wound outcome in 23 (64%) cases. In 13 cases, LDI did not correctly predict burn wound outcome. Eight were expected to heal within 14 days, but six of those eight took an average of 20.3 days to heal (range, 18-29 days), and the other two required skin grafting. Of the remaining five incorrect predictions, four were caused by an inability to correlate the flux scan with the clinical appearance of the burn, and one was thought to take more than 21 days to heal but healed within this period. Our data suggest that LDI appears to be a less reliable tool in predicting the outcome of friction burns when compared to other mechanisms of burn injury in children. This may reflect the physical differences in the mechanism of friction burns as opposed to other forms of thermal injury.
