The current study looked at plasma catecholamines, clinical autonomic function tests, and hemodynamic parameters in 10 ESRD patients (five men and five woman, aged 56.4 ± 3.6) with dialysis hypotension and 10 patients (five men and five women, aged 58.6 ± 4.2) without dialysis hypotension. Catecholamines were measured using high performance liquid chromatography- electrochemical detection (HPLC-ECD). Dialysis led to a significant decrease in mean arterial pressure (MAP) in the hypotensive group as compared with the normotensive group. Significantly higher basal (predialysis) plasma norepinephrine (NE) and dopamine levels (DA) were found in the hypotensive uremic group as compared with the normotensive group. Levels of plasma epinephrine (EP) were not significantly different between the normotensive and hypotensive groups. In response to postural stimulation, blood pressure fell in both groups, but the fall in the hypotensive group was significantly greater. Percentage increments of plasma catecholamines in response to postural stimulation in both groups were similar, however. Among the measured hemodynamic parameters, including total peripheral vascular resistance and left ventricular function (cardiac index and fractional shortening), only the cardiac index showed significantly lower values in the hypotensive group after dialysis, as compared with the normotensive group. Results of four tests of autonomic function indicated that although both groups responded similarly to hand-grip and cold-pressor tests, impaired responses to orthostasis and Valsalva maneuver after dialysis were observed in the hypotensive group. The MAP changes in dialysis in the hypotension prone group correlated inversely with predialysis plasma NE, but not with EP and DA. The MAP changes after dialysis in both groups also correlated positively with orthostatic pressure changes, cold-pressor changes, and Valsalva maneuver results. These data suggest that impaired autonomic and left ventricular function may both contribute to dialysis induced hypotension.
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