Cardiovascular function and alveolar gas exchange during isovolemic hemodialysis with acetate in healthy man

In order to elucidate the hemodynamic responses and alveolar gas exchange during isovolemic hemodialysis (IHD), without the influence of the uremic state and its complications, 7 healthy men underwent IHD. The dialysate contained acetate (40 mmol/l) and the sodium concentration was adjusted to the individual's predetermined plasma sodium concentration. By invasive techniques cardiac index (thermodilution), stroke index, heart rate, brachial and pulmonary arterial blood pressures, systemic vascular resistance index, central blood temperature, PaO2 and PaCO2 were measured. Calf vascular resistance was assessed by venous occlusion plethysmography. Plasma acetate was determined. A recirculation period of 30 min was followed by 120 min of IHD. During IHD plasma acetate increased to 2.51 +/- 0.30 mmol/l. Acetate provoked vascular dilatation, which was compensated for by a heart rate-dependent increase in cardiac index. Brachial arterial blood pressure and stroke index remained unchanged. PaCO2 and plasma bicarbonate decreased significantly, PaO2 tended to decrease and blood pH were unchanged. Thus, IHD with acetate in healthy man is mainly characterized by vasodilatation, but no cardiodepressive effects or marked hypoxemia. The adaptation to IHD is similar to that observed during treatment of uremic patients without complications.