Continuous Pulse-Oxymetry during Haemodialysis

Abstract

Continuous, non-invasive measurement of arterial oxygen saturation (SaO2) during haemodialysis was performed in 18 patients with chronic renal failure. They were dialyzed three times for 2 1/2-3 1/2 h weekly using a capillary polysulfone (F60) or a cuprophane (D2) filter. The total number of O2 saturation curves analyzed was 48. The whole group showed a significant mean decline in SaO2 by 1.9% as compared with predialysis values. In 7 patients with three or more recordings, the significant mean decline in SaO2 was 1.5-4.2% and occurred within 15-60 min after onset of haemodialysis. Evaluation of SaO2 during episodes of severe depression of blood pressure was not possible due to loss of the signal as a consequence of peripheral vasoconstriction. Changes in SaO2 which occurred without any clinical signs or symptoms included very short episodes of depression of SaO2 by 3-22%; a decrease in SaO2 by 3-6% occurring towards the end of the treatment and followed by depressed values for a period of 20-60 min; episodes of marked instability of SaO2 values with differences of up to 10%, lasting 20-60 min and occurring towards the end of the treatment. Application of cuprophane instead of polysulfone filter membranes, first use and reuse of dialyzers, and microemboli blood filters were not found to influence the changes in SaO2. There was a significant difference in the initial decrease in SaO2 during acetate as compared with bicarbonate dialysis.