Background: Established renal failure in diabetes is associated with a high incidence of foot ulcers and gangrene, and these are major causes of morbidity and mortality. It has been suggested that this problem is particularly associated with the onset of renal replacement therapy, and since there is evidence that haemodialysis causes hypoxaemia, we have undertaken a pilot study to determine the effect of haemodialysis on lower limb transcutaneous oxygen tension (TcpO2).
Methods: TcpO2 was measured on the dorsum of the foot through a single dialysis treatment and over the succeeding 4 h using a transcutaneous monitor (TCM400/3, Radiometer Ltd, Copenhagen, Denmark).
Results: The median age (range) of the 10 (7 male) participants was 73 (58-83) years. The median duration of diabetes was 16.5 (7-30) years and that of dialysis treatment 29 (10-88) months. The median (range) baseline TcpO2 on the dorsum of the foot was 54.5 (51-77) mmHg and 54.0 (24-87) at the end of dialysis. Median TcpO2 at 1, 2 and 4 h after the end of dialysis was 50.0 (33-81), 49.0 (24-78) and 47.0 (20-78) mmHg. Analysis by ANOVA suggested a trend towards a difference between median TcpO2 concentrations at different time points (F(1.752, 15.765) = 3.359, P = 0.066).
Conclusions: The data identified a trend towards a fall in lower limb TcpO2, and that this fall continued for at least 4 h after the end of treatment. Dialysis-associated lower limb hypoxia may be a factor leading to the increased incidence of critical limb ischaemia in this group and further work is needed to define its cause and implications for clinical care.