A comparison of laser Doppler fluxmetry and transcutaneous oxygen pressure measurement in the dysvascular patient requiring amputation.

OBJECTIVE: To determine the predictive power of laser Doppler fluxmetry (LDF), both heated and unheated, as a preoperative investigation of wound healing potential in dysvascular patients requiring amputation, by comparison with transcutaneous oxygen pressure measurement (TcpO2) and the limb to chest TcpO2 index.

METHODS: Thirty-five non-diabetic patients with peripheral vascular disease were investigated before amputation. Heated and unheated LDF and heated TcpO2 measurements were taken on the chest wall and at the routine above-knee, below-knee and mid-foot amputation levels. Wound healing potential was evaluated against a TcpO2 index value of 0.55 and on clinical outcome.

RESULTS: A heated LDF value of 4.9 arbitrary units (au) was shown by receiver-operator characteristic curve to have the best predictive power, with an overall accuracy for preoperative prediction of wound healing of 91.4%, and a predictive value for wound failure of 89%. Based on the heated LDF of 4.9 au, review of 26 amputations performed shows the overall accuracy for preoperative prediction of wound healing of 92.3%, a predictive value for wound healing of 100%, and a predictive value for wound failure of 62.5%.

CONCLUSION: A heated LDF value of 4.9 au appears to be a useful predictor of the potential of an amputation site to heal.