Monitoring intracellular, interstitial, and intravascular volume changes during fluid management procedures

Area of Science:

• Biomedical Engineering
• Physiology
• Medical Devices

Background:

• Fluid management is critical in various medical procedures, especially for patients with end-stage renal disease.
• Accurate, real-time monitoring of fluid volume shifts is essential for effective treatment.
• Current methods for monitoring fluid status can be invasive or provide delayed results.

Purpose of the Study:

• To evaluate the clinical feasibility and validity of a novel bioimpedance spectroscopic (BIS) analytical algorithm.
• To demonstrate the algorithm's capability in computing compartmental volume shifts during fluid management.
• To compare BIS-derived fluid volume changes with established monitoring techniques.

Main Methods:

• Developed and applied a BIS analytical algorithm for non-invasive measurement of fluid volumes.
• Validated the algorithm using data from 20 end-stage renal disease patients undergoing hemodialysis.
• Compared BIS-derived hematocrit profiles with simultaneous measurements from a CritLine® monitor during 60 hemodialysis sessions.
• Employed regression and Bland-Altman analyses to assess agreement between BIS and CritLine® measurements.

Main Results:

• The BIS algorithm reliably derived continuous, real-time rates of change for compartmental fluid volumes.
• Regression analysis showed an R² > 0.99 between BIS-derived and CritLine® hematocrit values.
• Slopes of regression equations indicated an almost one-to-one correspondence between the two measurement methods.
• Bland-Altman analysis confirmed that the BIS algorithm is interchangeable with the CritLine® monitor for hematocrit measurement.

Conclusions:

• The study validates the clinical feasibility and accuracy of the BIS analytical algorithm for fluid volume monitoring.
• BIS provides real-time, continuous measurements of intravascular, interstitial, and intracellular fluid volume changes.
• This novel algorithm enhances fluid management strategies by offering precise, non-invasive monitoring capabilities.