Application of laser speckle perfusion imaging in predicting wound healing time of burn patients

Objective: To explore the application effect of laser speckle perfusion imaging (LSPI) in predicting wound healing time of burn patients. Methods: LSPI was performed in 84 adult burn patients hospitalized in department of burns of Tongren Hospital of Wuhan University & Wuhan Third Hospital within post injury hour (PIH) 24 to 72 to detect the blood perfusion values of the wounds. The wound healing time was recorded. The 128 wounds were divided into superficial group (wound healing time shorter than or equal to 14 d, n=57) and deep group (wound healing time longer than 14 d and shorter than or equal to 28 d, n=71) according to the healing time. The blood perfusion values of the two groups were compared. Data were processed with t test or chi-square test. The receiver operating characteristic (ROC) curve was drawn and Youden index was calculated to determine the optimal critical blood perfusion value of wound healing time of the two groups, and the validity of the critical value was assessed by Kappa consistency test. Results: (1) The blood perfusion value of woundsin superficial group was (6.8±1.8) perfusion unit (PU), which was significantly higher than (3.5±1.3) PU in deep group (t=11.404, P<0.01). (2) The total area under ROC curve of blood perfusion value to predict wound healing time was 0.931 (with 95% confidence interval 0.887-0.975, P<0.01). Combined with Youden index, 5.52 PU was chosen as the optimal critical value of wound healing time of the two groups, with sensitivity of 76.9% and specificity of 94.7%. (3) The healing time of 44 wounds predicted was shorter than or equal to 14 d, and the healing time of 84 wounds predicted was longer than 14 d and shorter than or equal to 28 d, while the actual number of wounds was 57 and 71, respectively. The Kappa coefficient of consistency test was 0.754 (P<0.01). Conclusion: LSPI is a useful method to predict the healing time of burn wounds.