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Objective: ischaemic lower-extremity ulcers in the diabetic population are a source of major concern because of the associated high risk of limb-threatening complications. The aim of this study was to evaluate the role of hyperbaric oxygen in the management of these ulcers., Method: eighteen diabetic patients with ischaemic, non-healing lower-extremity ulcers were recruited in a double-blind study. Patients were randomly assigned either to receive 100% oxygen (treatment group) or air (control group), at 2.4 atmospheres of absolute pressure for 90 min daily (total of 30 treatments)., Results: healing with complete epithelialisation was achieved in five out of eight ulcers in the treatment group compared to one out of eight ulcers in the control group. The median decrease of the wound areas in the treatment group was 100% and in the control group was 52% (p=0.027). Cost-effectiveness analysis has shown that despite the extra cost involved in using hyperbaric oxygen, there was a potential saving in the total cost of treatment for each patient during the study., Conclusion: hyperbaric oxygen enhanced the healing of ischaemic, non-healing diabetic leg ulcers and may be used as a valuable adjunct to conventional therapy when reconstructive surgery is not possible.

Objective: The objective of our study was to investigate whether such an incision results in a reduction in blood flow, and therefore haemoglobin oxygen saturation, across the wound., Design: Microvascular oxygenation was measured with lightguide spectrophotometry in 21 patients undergoing femoropopliteal or femorodistal bypass procedures. A series of measurements were made in the groin, medial and lateral to the surface marking of the femoral artery. The mean oxygen saturation on each side was calculated, and the contra-lateral groin was used as a control. The measurements were repeated at 2 and 7 days postop., Results: Oxygen saturation in the skin of the operated groins was increased significantly from baseline at 2 days postop (f = 25.80, p < 0.001) and had begun to return to normal by day 7. The rise was more marked on the lateral side of the wound than on the medial (f = 12.32, p < 0.001). There was no such difference in the control groins. All wounds healed at 10 days., Conclusions: These results show a significant difference in skin oxygenation between the lateral and medial sides of the groin following longitudinal incision. This may contribute to the relatively high incidence of postoperative infection in these wounds.

Eleven patients (eight women) underwent urgent revascularisation for acute-on-chronic mesenteric ischaemia. Four patients had dual vessel and seven single vessel reconstructions. Two patients underwent simultaneous bowel resection and one patient has had three separate grafts to the superior mesenteric artery. There were two peri-operative deaths and three have died in the late follow-up period after 18, 24 and 36 months. The remainder have survived for between five and 63 months. Revascularisation for acute-on-chronic mesenteric ischaemia has been shown to be technically possible and of substantial benefit to patients who would otherwise be treated as terminal cases.

Purpose: To quantitate the workload, resource requirement and outcome involved in the management of patients with chronic limb-threatening ischaemia when adopting an aggressive reconstructive policy., Methods: Prospective clinical audit of all patients with severe lower limb ischaemia presenting to a single specialist Vascular Surgeon in a 3 year period., Results: A total of 228 patients were treated with 275 severely ischaemic limbs. Two hundred and thirty-five limbs (85.5%) had procedures to improve blood supply, 19 (6.9%) underwent primary amputation and 21 (7.7%) were treated conservatively. The principal outcome measures were limb-salvage, death and graft patency. The cumulative limb-salvage, including those undergoing primary amputation, at 30 days, 1, 2, 3 and 4 years was 94.2%, 82.7%, 73.1%, 68.3% and 65.3% respectively. The cumulative patient survival was 91.7%, 69.2%, 58.1%, 47.9% and 40.6% for the same intervals. For reconstructive vascular surgery, excluding amputation and rehabilitation, a total of 383 hospital admissions were required covering 7343 hospital days, 64.5% of patients were managed in a single admission. The median duration of stay was 16 days for the first admission. Operations included 361 separate procedures to improve blood supply and 70 major limb amputations., Conclusions: The management of chronic limb-threatening ischaemia presents major resource implications. An acceptable limb-salvage rate can be achieved although there is a high initial mortality. In view of the poor overall survival any benefits for these patients should be viewed as relatively short-term objectives.

The aim of this experimental study was to investigate whether lightguide spectrophotometry in the visible wavelength range in skin could be used to predict stump healing viability in patients with critical lower limb ischaemia. Remission spectra recorded at two sites (medial and lateral) on the line of a proposed trans-tibial amputation (TTA) and at 10mm intervals along the leg were analysed to give haemoglobin oxygenation (SO2). Degree of tissue hypoxia (DTH) along the leg was defined as the percentage of values along the leg less than 10% SO2. DTH and mean SO2 values were compared with skin blood flow values ((I125) 4-Iodoantipyrine clearance technique) and clinical outcome of trans-tibial amputation, (TTA) or trans-femoral amputation (TFA), in 41 patients. SO2 histograms were also measured in 12 normal subjects for comparison. The results of the study allowed the establishment of criteria for the accurate prediction of flap healing potential. Successful TTAs all displayed a minimum mean SO2 at the medial and lateral measurement sites of 30%, together with a maximum degree of tissue hypoxia of 15% along the limb. The combination of these criteria gave a sensitivity and selectivity of 1.0 for prediction of a successful outcome of TTA.

Skin blood flow (SBF) values were estimated on the posterior, medial and lateral aspects of the lower leg in 47 patients presenting for assessment of amputation level. Measurement was made using a radioisotope (iodoantipyrine) clearance technique. Medial SBF was 9.0 +/- 5.2 ml 100 g-1 min-1; posterior SBF was 8.3 +/- 5.0 ml 100 g-1 min-1 and lateral SBF was 6.5 +/- 4.1 ml 100 g-1 min-1. The results gave significantly higher SBFs on the medial and posterior aspects of the ischaemic leg. The finding of an uneven distribution of blood flow at the below knee amputation level has important implications in the planning of amputation flaps.

Assessment of the optimum level of amputation of an ischaemic limb can be exceptionally difficult. For this reason there has been an intensive effort, particularly in the past 20 years, to find suitable non-invasive ancillary methods to aid in the amputation level selection. This paper reviews three separate research and development areas which have evolved simultaneously in our laboratory: skin partial oxygen pressure, skin blood flow, and infrared thermography. The physiological basis for each of these measurements is discussed along with the merits and demerits of each.

Digital systolic pressure measurements were made on 140 big toes using a photoplethysmographic technique before and after extrinsic heating of the foot. Most patients with apparent, critically ischemic feet demonstrated vasomotor activity, suggesting that much of the microcirculation of the foot was in fact intact. Significantly, nine of 21 feet which would have fallen into a critically ischemic category were recategorized after heating into a less severe group. These data confirm the value of toe pressure measurements in the assessment of severe ischemia but show that adequate foot vasodilation is essential to allow accurate conclusions to be drawn and to allow meaningful interpretation of results.

Transcutaneous oxygen (PtcO2) measurements were made on 46 patients with severe ischaemia of the lower limbs and on 17 age-matched controls. Values breathing air, 100 per cent oxygen and the rate of change of PtcO2 breathing oxygen were recorded. Of 29 below knee amputations there were 4 failures; 16 had PtcO2 values less than 35 mmHg, but 12 of the 16 healed. When the rate of change of PtcO2 during oxygen inhalation was greater than 9 mm Hg/min all below knee amputations healed; all 4 failures were found to have values less than 9 mm Hg/min while only one patient with a value of less than 9 mm Hg/min healed a below knee amputation. This study shows that low PtcO2 values are a poor indication of healing potential. A more reliable index of skin viability is provided by the dynamic measurement of PtcO2 changes during oxygen inhalation. The addition of an oxygen inhalation test, when making PtcO2 measurements, greatly enhances the applicability of the technique in the assessment of the oxygen supply to the skin.

Segmental systolic pressures were measured in a group of patients with clinically irreversible ischemia. There was a good relationship between the level of pressure in a limb and the eventual outcome, but a particular level of pressure was found to be a poor indicator of a specific level of viability. These results support previous concern about the limitations of systolic pressure measurements in determining the level of limb viability. We suggest that local intrinsic regulation of the microcirculation plays a major role in the ultimate survival of tissues in an ischemic limb.

Transcutaneous oxygen measurements (TCPO2) are being used increasingly for the assessment of tissue viability in the ischaemic limb. The major objective with such a technique is to determine the critical level of TCPO2 which defines the boundary between skin viability and non-viability. To be able to do this, an assumption is made that measurements from different centres using various TCPO2 sensors are comparable. This study shows that static and dynamic changes of TCPO2 (air to oxygen breathing) made with two commercially available instruments are not directly comparable. We suggest that the physical characteristics of present TCPO2 electrodes are not optimal for measurements on adult skin. TCPO2 measurements made in conditions of skin ischaemia should be interpreted with caution because the ratio of local oxygen demand to blood flow is such that the measurement may be underestimated by TCPO2 electrodes with a high oxygen consumption.

Twenty patients with ischemic rest pain were treated with intravenous pentoxifylline, 1,200 mg daily, for up to three weeks. Ten patients obtained sufficient relief to avoid surgical intervention. Seven of these had complete or near complete relief of rest pain, but the other three required continuing analgesia. Transcutaneous oxygen measurements showed a significant increase after the course of treatment. There were marked gastrointestinal side effects in six patients, necessitating early withdrawal from the study. Three of these six patients had shown a favorable response to medication prior to withdrawal. These preliminary results suggest that pentoxifylline may provide a sufficient increase in tissue oxygen availability to avoid, or at least postpone, surgical intervention. A double blind controlled study is required to further assess the efficacy of this drug as an intravenous treatment.