The Changes in Relative Blood Volume during Dialysis Are Characterized by Ultrafiltration Rate and Predialysis Blood...

Area of Science:

• Nephrology
• Physiology
• Biomedical Engineering

Background:

• Continuous monitoring of relative blood volume (percentage BV) is crucial in hemodialysis (HD) for dry weight determination and preventing intradialytic hypotension.
• The underlying causes of blood volume variation during HD remain unclear.
• This study investigates factors influencing percentage BV changes.

Purpose of the Study:

• To identify factors affecting relative blood volume (percentage BV) changes during hemodialysis (HD).
• To analyze the relationship between early and late phase BV dynamics and patient predialysis data.

Main Methods:

• A formula with coefficients (a, τ, b) was developed to predict percentage BV changes.
• Percentage BV was measured in 18 end-stage renal disease patients undergoing HD.
• Least squares optimization and correlation analysis were used to estimate coefficients and analyze relationships with predialysis data.

Main Results:

• Ultrafiltration rate (UFR) negatively correlated with the late phase BV decrease coefficient (b) (r = -0.851, p < 0.01).
• Predialysis serum total protein negatively correlated with the early phase BV decrease coefficient (a) (r = -0.531, p = 0.042).
• UFR and predialysis total protein did not significantly correlate with the transition phase coefficient (τ).

Conclusions:

• UFR impacts late-phase BV decrease, while predialysis total protein influences early-phase BV decrease.
• Colloid oncotic pressure, indicated by total protein, is vital for early plasma refilling.
• These findings differentiate the drivers of BV changes in early versus late HD phases, informing clinical management.