Prediction of amputation wound healing: the role of transcutaneous pO2 assessment

With the recent trend towards more distal lower limb and below-knee amputation for peripheral vascular disease, failure of amputation healing remains a common clinical problem. There is an urgent need for more objective measures of selecting the most appropriate distal amputation level compatible with healing. Oxygen availability is the final arbiter of tissue viability and healing potential, and we have shown that the measurement of transcutaneous pO2 (TcpO2) accurately reflects the degree of ischaemia in the lower limb. In 59 patients having 62 amputations for peripheral vascular disease significantly lower TcpO2 levels were related to amputation failure. Below-knee amputations with a pre-operative below-knee TcpO2 of above 35 mmHg always healed, and failures had levels of 35 mmHg or less. Nine out of sixteen patients having above-knee amputations had pre-operative below-knee TcpO2 values well above 35 mmHg, suggesting that they may possibly have undergone successful below-knee amputation. No correlation between ankle systolic pressure and amputation healing was found. TcpO2 measurement is simple, non-invasive and reliable and offers an exciting research advance in the assessment of effective tissue perfusion.