[Hypoxemia in hemodialysis: hemodynamic mechanism? Hemodynamic and spirometric study using acetate and bicarbonate buffers].

The background of this study is the occurrence during acetate hemodialysis (HDA) of arterial hypoxemia associated with well described vasodilatator hemodynamic changes. Our aim was to evaluate the relationship between these 2 phenomena. Eleven patients (7 males, 4 females, mean age 54 years) were compared in a protocol of HDA and bicarbonate hemodialysis (HDB) as regards their cardiac output measured by the dye dilution method, blood gases and respiratory gas measurements made at the bedside. The results show significant hypoxemia with hypocapnia as soon as the 30th minute of HDA and no significant variation of cardiac index. No significant variation of respiratory response was noted. Arterial prostaglandin levels rose significantly higher during HDA (+ 302%) than HDB (+ 163%; 2 alpha less than 0,05). The absence of a correlation between arterial hypoxemia and hemodynamic changes in HDA compared to HDB suggests that the phenomena are not interdependent. The importance of increased thromboxane activation in HDA will require further investigation.