Kidney Week

Abstract: SA-PO768

Modified Compression Bioimpedance in Edema Quantification in Patients on Hemodialysis

Session Information

• Standard Hemodialysis for ESRD - I
  November 04, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Dialysis

• 601 Standard Hemodialysis for ESRD

Authors

• Singh, Amit P, University of Michigan Health System, Ann Arbor, Michigan, United States

Amit P Singh,

• Pitre, John J., Tulane University, New Orleans, Louisiana, United States

John J. Pitre,

• Bull, Joseph L., Tulane University, New Orleans, Louisiana, United States

Joseph L. Bull,

• Koziol, Leo, University of Michigan Health System, Ann Arbor, Michigan, United States

Leo Koziol,

• Weitzel, William, VA Ann Arbor Health System, Ann Arbor, Michigan, United States

William Weitzel,

• Rao, Panduranga S., University of Michigan Health System, Ann Arbor, Michigan, United States

Panduranga S. Rao,

Background

Quantification of edema in dialysis patients is subjective and problematic. Given the importance of fluid overload, objective measures are necessary.

Methods

We conducted a clinical study using bioimpedance and circumferential strain apparatus for quantification of lower extremity edema in hemodialysis patients. Eleven stable hemodialysis patients, 18-85 years of age, with varying grades of clinical edema participated. During their usual hemodialysis session, a series of compression cycles (30 seconds, 50mm Hg) were applied above one ankle using a blood pressure cuff. Bioimpedance and strain data were collected using the bioimpedance meter and plethysmograph, respectively. This procedure was repeated until the completion of the dialysis session.

Results

Using the strain data we calculated the volume of mobilized fluid during compression. Using the bioimpedance data we calculated the total volume of fluid underneath the cuff. The median volume of fluid estimate for each subject was used to normalize the volume of mobilized fluid obtained from the strain measurements. These data, along with the fit parameters for the strain data, were plotted as a function of the edema grades. Of the three strain fitting parameters (ε₀, ε_∞ - ε₀ and τ), the ANOVA revealed significant differences among edema grades for both the instantaneous strain ε₀ (p < 2×10^-16) and the viscoelastic strain ε_∞ - ε₀ (p < 2×10^-16). ANOVA also revealed significant differences among edema grades for the strain-based estimate of the volume of mobilized fluid V_f^m (p < 2×10^-16); bioimpedance based total fluid volume (p = < 2×10^-16) and relative volume of mobilized fluid (p < 2×10^-16).

Conclusion

Using this novel technique in dialysis patients we demonstrated the potential to quantify mechanical characteristics of edema, ε₀, ε_∞ - ε₀ and τ, to better characterize peripheral edema.

Violin plots of strain fit parameters and estimates of volume parameters.

Funding

• Private Foundation Support