Early identification of diabetic foot ulcers that may require interventionusing the micro lightguide spectrophotometer

OBJECTIVE - Adequate tissue oxygenation is known to be essential for the he aling of diabetic foot ulcers, but hypoxia has also been shown to be a pote nt stimulus for growth. There are no studies looking specifically at ulcer oxygen levels during the healing process. We measured the serial microvascu lar oxygen saturation (SaO(2)) of the foot ulcer, the ulcer margin, and a c ontrol site using the Erlangen micro lightguide spectrophotometer (EMPHO II ; Bodenseewerk Geratetechnik, Erlangen, Germany) to study serial changes du ring healing. RESEARCH DESIGN AND METHODS - Studied over 9 months were 14 patients with n europathy with a total of 24 foot ulcer sites. Of these patients, four (sev en ulcers) had significant ischemia as determined by the ankle-brachial pre ssure index (ABPI) and transcutaneous oxygen tension. RESULTS - Of 21 ulcer sites with serial measurements, only 13 ulcers healed . In those ulcers, a significant reduction (P < 0.05) in SaO(2) occurred wi th healing. SaO(2) dropped from 58% at initial presentation (mean area 2.6 cm(2)) to 47% at midsize (mean area 1.2 cm(2) at 5.2 weeks) and finally red uced to 45% just before it healed. Similar trends were also seen around the margin of the ulcers (initial 49%, midsize 45%, and final 41%; P = 0.1). H owever, there were no such changes on the control sites (43, 40, and 40%; P = 0.5) or within the eight ulcers that did not heal (46, 42, and 53%; P = 0.2). CONCLUSIONS - Serial microvascular oxygen measurements may be used to ident ify at an early stage those ulcers that are unlikely to heal and, therefore , need surgical intervention.