Arterial hypoxemia during hemodialysis for acute renal failure in mechanically ventilated patients: observations and mechanisms.

Changes in arterial oxygen tension (PaO2) during hemodialysis have been measured in eight patients with acute renal failure who were being mechanically ventilated. Falls in PaO2 under these circumstances (mean = 22.44%, P < 0.05) suggest that loss of carbon dioxide into the dialyzate is not an important cause of arterial hypoxemia during dialysis. White blood count, platelet count and complement levels have also been measured; there is a dissociation between these parameters and falls in PaO2, suggesting that other, unidentified factors are involved in hemodialysis hypoxemia.