Segmental Intracellular, Interstitial, and Intravascular Volume Changes during Simulated Hemorrhage and...

Area of Science:

• Biomedical Engineering
• Physiological Monitoring
• Fluid Management Technology

Background:

• Accurate real-time measurement of segmental blood flow and body fluid volumes is crucial for effective clinical management.
• Existing methods may lack the noninvasive, comprehensive capabilities needed for dynamic fluid shifts.

Purpose of the Study:

• To introduce a novel combined impedance plethysmographic (IPG) and electrical bioimpedance spectroscopic (BIS) instrument and software.
• To demonstrate the instrument's capability for noninvasive, real-time measurement of segmental blood flow and fluid volume changes.
• To validate the technology in monitoring physiological responses during simulated hemorrhage and resuscitation.

Main Methods:

• Development of a dual-mode impedance device operating as fixed-frequency IPG or multi-frequency BIS.
• Utilizing BIS to record intracellular and extracellular resistances across 40 frequencies.
• Deconvoluting extracellular volume to determine intravascular and interstitial components over time.
• Testing the instrument on a pig model during simulated hemorrhage and resuscitation.

Main Results:

• The combined IPG-BIS instrument successfully performed noninvasive, real-time measurements.
• Segmental blood flow, hemodynamics, and fluid compartment volumes (intracellular, interstitial, intravascular) were quantified.
• The system effectively monitored volume responses during simulated hemorrhage and resuscitation in a pig model.

Conclusions:

• The developed IPG-BIS instrument provides valuable real-time data on segmental blood flow and fluid volumes.
• This technology offers a promising tool for diagnosing and managing rapid changes in body fluid balance.
• The instrumentation can support various clinical treatments requiring precise fluid management.