A study of the extracorporeal rate of blood flow and blood pressure during hemodialysis.

Hemodynamic instability is a common problem during hemodialysis (HD). The effect of blood flow rate (BFR) on blood pressure (BP) during HD has not been previously evaluated. Subjects receiving HD for the treatment of renal failure were enrolled (n=34). For each patient, during the last hour of 2 consecutive HD sessions the BFR was set at 200 mL/min for 30 min and at 400 mL/min for 30 min, during which period the fluid removal rate was kept constant. The order of the BFR alterations was randomized. The study procedure was repeated during the next HD session but with reversal of the order of the altered BFR. During each 30-min period, BP was recorded at baseline and subsequently every 10 min. During the BFR of 400 mL/min, subjects had a higher systolic BP by an average of 4.1 mmHg compared with the BFR of 200 mL/min (95% confidence interval [CI] 0.22-7.98; p=0.038). Similarly, during the BFR of 400 mL/min, subjects had a higher diastolic BP by an average of 3.04 mmHg compared with the BFR of 200 mL/min (95% CI 0.55-5.53; p=0.017). Likewise, during the BFR of 400 mL/min, subjects had a higher mean arterial pressure by an average of 3.44 mmHg (95% CI 0.77-6.11; p=0.012). The findings suggest that during HD, BPs are maintained higher at higher BFRs as compared with lower BFRs.