Hypoxemia and hemodialysis-induced symptomatic hypotension

We studied a possible involvement of hypoxemia in the pathophysiology of hemodialysis (HD)-induced symptomatic hypotension (SH). SH frequently recurred in 16 of 33 patients undergoing routine HD. These 16 patients showed a significantly (p less than 0.001) lower arterial oxygen tension (PaO2) prior to the start of HD than the remaining 17 patients without SH. This was the case when 10 patients with SH who had no additive risk factors for SH such as older age, excessive fluid loss and autonomic neuropathy were compared with a corresponding 11 patients without SH (p less than 0.001). Sequential monitoring of PaO2 throughout HD using the intravascular O2 electrode revealed that SH was never associated with particular changes in PaO2. The pattern of the decrease in, and the minimum value for, PaO2 during HD was not significantly different between the patients with and without SH. Furthermore, O2 administration during HD failed to prevent the occurrence of SH. These data suggest that pre-existing, but not HD-induced, hypoxemia is profoundly related to the pathophysiology of SH.