ABSTRACT
BACKGROUND: Although the dynamics of blood pressure (BP) during dialysis provide information related to the control system, the prognosis and relationships between temporal changes in intradialytic hemodynamic regulation, BP, and decreased cardiac function remain largely unclear. METHODS: Hemodynamic parameters, including heart rate (HR), stroke volume (SV), cardiac index, and systemic vascular resistance index, were recorded using a noninvasive hemodynamic device on a beat-by-beat basis in 40 patients on dialysis who were divided into three groups, i.e., those with and without BP lability and those with heart failure (HF). Statistical measurements, including mean, standard deviation, coefficient of variation (CV), and index of nonrandomness of each hemodynamic parameter were derived from the three different phases divided equally during dialysis and compared using 3×3 two-way mixed-model analysis of variance to determine the effects of the different stages of hemodialysis (HD), cardiac function, and intradialytic changes in BP on the hemodynamic parameters. In addition, multivariate Cox regression was performed to determine the association between the changes in the derived parameters and BP lability. RESULTS: The average SV tended to decrease during HD in all groups (p = 0.041). A significant decrease was observed in the CV of SV between the first two stages of HD in patients with labile BP and HF when compared to those without labile BP (p = 0.037). Significant interactions between group and stage of the index of nonrandomness for HR were also noted; this index was significantly higher in patients without labile BP than in those with labile BP or HF (p = 0.048). A higher difference between the early and middle stages of HD for nonrandomness indexes of HR was an independent predictor of reduced BP lability during HD (HR = 0.844, 95% confidence interval 0.722-0.987, p = 0.034). CONCLUSIONS: Increases in the CV of SV and the index of nonrandomness for HR during early-stage HD in response to decreased SV may be associated with better BP control during HD. This finding suggests that patients with more structurally meaningful hemodynamic control have a more favorable cardiovascular outcome.
