Twenty-one stable maintenance
hemodialysis patients were studied in a crossover format with
hemofiltration to determine whether the lower incidence of symptomatic
hypotension noted with
hemofiltration could be correlated with changes in baroreflex function as tested using the cold pressor test and
amyl nitrite inhalation study. Baroreflex function remained abnormal and unchanged in all patients in the face of a reduced incidence of symptomatic
hypotension. Subdivision of the patients into frequent (greater than 1 episode/treatment) and infrequent (less than 1 episode/treatment) reactors during the
hemodialysis control period resulted in the infrequent reactors, showing a significant increase in episodes of symptomatic
hypotension/
hemofiltration treatment where a significant reduction was noted with the frequent reactors. No clear correlation could be made between the incidence of symptomatic
hypotension and the pre- to post-treatment change in body temperature. The presence of pretreatment
hypertension, another previously identified correlate of symptomatic
hypotension with
hemodialysis, also could not be corroborated. Further, changes from baseline predialysis values in mean arterial pressure noted with
hemofiltration could not be correlated with a changed incidence of symptomatic
hypotension. We conclude that previously identified correlates of symptomatic
hypotension noted in the
hemodialysis setting may be dissociated during treatment with
hemofiltration and that there is a heterogeneous patient response to this treatment. These data suggest that there are additional, as yet undetermined, pathophysiologic events that underly the symptomatic
hypotension of
artificial kidney treatment.