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Abstract: SA-PO756

Using Intradialytic Blood Pressure Slopes to Assess Extracellular Volume in Hemodialysis Patients

Session Information

Category: Dialysis

  • 601 Standard Hemodialysis for ESRD


  • Van Buren, Peter N., UT Southwestern, Dallas, Texas, United States
  • Liu, Hao, UT Southwestern Medical Center, Dallas, Texas, United States
  • Sonderman, Mark T., UT Southwestern Medical Center, Dallas, Texas, United States
  • Shastri, Shani, UT Southwestern, Dallas, Texas, United States

Extracellular volume (ECV) overload increases mortality risk in hemodialysis (HD) patients, but there is no standardized clinical method to assess ECV in them. We evaluated the association between slopes of multiple intradialytic blood pressure (BP) measurements with bioimpedance spectrscopy (BIS)-determined measurements of ECV overload as a novel method to assess ECV using routine clinical data.


We measured systolic BP every 30 minutes in a mid-week HD treatment. Using multifrequency BIS, we measured pre and post HD extracellular water (ECW), total body water (TBW), ECW/TBW and ECW/weight. Using Pearson correlation and mixed linear regression we compared associations between post-HD ECV overload with multiple peridialytic BP metrics.


Mean intradialytic BP slope (n=58) was -0.06 mmHg/min (±0.1). The correlation between this slope and post-HD ECW/body weight was 0.4 (p=0.003) in all subjects and 0.51 (p<0.0001) in those with post-HD hypertension (SBP>130 mmHg, n=45)(figure 1). This significant association persisted after controlling for age, gender and ultrafiltration rate (β=1.9,p<0.001) and was stronger than associations wtih slope and other ECV metrics. ECW/body weight had a stronger association with intradialyltic BP slope than with pre-HD (r=-0.2, p=0.3), post-HD (r=0.2, p=0.1), or delta SBP (r=0.2, p=0.09).


There is a significant correlation between intradialytic BP slopes and BIS based measurements of ECV overload in hypertensive HD patients. The slope of multiple intradialytic BP measurements better assesses ECV than pre, post or delta SBP. Determining intradialytic blood pressure slope is an innovative way to objectively assess ECV in HD patients.

Among HD patients with post-HD SBP>130, the correlation coefficient for Intradialytic Blood Pressure Slope (mmHg/min) and post-HD ECW/body weight is 0.51 (p<0.0001).


  • NIDDK Support