The time factor in the LDI (Laser Doppler Imaging) diagnosis of burns

Abstract

Background and objective: The not quite rare occurrence of inaccurate clinical diagnoses of burns in early post-burn days leads to an inappropriate conservative treatment strategy, or unnecessary surgery. LDI (Laser Doppler Imaging) objectively evaluates skin blood circulation, which correlates with the depth of the burn and the length of healing. The aim of this work was to suggest cutoff values for detecting burns without healing potential within 3 weeks, which should have undergone surgery.

Method: The burned area's average blood perfusion of 148 burns was measured on 115 patients, using the Laser Doppler Imager PIM III. A total of 268 measurements were performed from the one to the ninth post-burn day (PBD). The perfusion values were compared to the healing time or histology in the case of the surgical treatment. Cutoff values indicating surgery were investigated in various post-burn days; the ROC analysis was used.

Results: This work suggest statistically significant increasing cutoff values for indication to surgery (P = 0.05). From the third to the fifth day 148.5 perfusion units (PU), from the sixth to the seventh day 186.0 PU, from the eighth to the ninth PBD 269.5 PU. The cutoff value is not possible to establish until the second day.

Conclusion: LDI is a useful method for wound healing prediction and an indication of the necessity of surgery. We have demonstrated that the diagnosis of the healing capacity of LDI needs to take into account the factor of time.

Keywords: healed; perfusion scan; perfusion unit (PU); postburn day (PBD); unhealed.