PULSE OXYMETRY EVALUATION OF OXYGEN-SATURATION IN THE UPPER EXTREMITYWITH AN ARTERIOVENOUS-FISTULA BEFORE AND DURING HEMODIALYSIS

We noticed that some patients with arteriovenous (AV) fistula on chron ic hemodialysis experience pain in the limb with the fistula a short t ime after being connected to the dialysis machine. We postulated that the pain is caused by relative ischemia and therefore performed this s tudy to determine whether oxygen saturation (SaO(2)) of the extremitie s with AV fistula decreases during hemodialysis. Seventy-two patients with a side-to-side primary AV fistula were evaluated by pulse oxymetr y, SaO(2) was measured before hemodialysis and 20 minutes after initia tion of dialysis. The contralateral arm served as a control, In 48 pat ients, SaO(2) difference between the arms of each patient before hemod ialysis was less than 4%. SaO(2) values of this group of patients did not change significantly 20 minutes after initiation of dialysis. In 2 4 patients, SaO(2) differences between the hands of each patient befor e hemodialysis were 4% or more, In this group of patients, SaO(2) valu es of the hands with the AV fistula decreased significantly 20 minutes after hemodialysis from a mean of 90.85 +/- 2.84% to 81.60 +/- 3.94 ( P < 0.001). SaO(2) remained unchanged in the contralateral arm. Nine p atients in this group complained of pain and change in sensation in th e arm with the fistula during hemodialysis. One patient complained of severe pain in the arm with the fistula before hemodialysis, and SaO(2 ) was unmeasurable. We conclude that, in some patients, SaO(2) of the arm with the AV fistula decreases only during hemodialysis, This pheno menon may be symptomatic, A predialysis SaO(2) difference of 4% or mor e between the arms predicts decreased SaO(2) of the arm with the AV fi stula during hemodialysis. (C) 1997 by the National Kidney Foundation, Inc.