Clinically applicable model-based method, for physiologically accurate flow waveform and stroke volume estimation.

Area of Science:

• Physiological modeling
• Cardiovascular monitoring
• Hemodynamic assessment

Background:

• Accurate, continuous stroke volume (SV) and cardiac output (CO) are crucial for managing cardiovascular dysfunction.
• Current direct SV/CO measurements are invasive, and continuous methods often require recalibration after hemodynamic instability.
• A need exists for a non-additively invasive method for continuous SV/CO monitoring that avoids recalibration.

Purpose of the Study:

• To present a clinically applicable, physiological model-based method for measuring SV and CO.
• To demonstrate that this method does not require recalibration during or after hemodynamic instability.

Main Methods:

• Development of a physiological model for SV and CO estimation.
• Validation in an animal trial involving 5 pigs with induced sepsis.
• Comparison of model-estimated SV and CO with measurements from an aortic flow probe.

Main Results:

• The model demonstrated a mean percentage error of -2% for beat-to-beat SV estimation compared to an aortic flow probe.
• 90% of SV estimations fell within -24.2% and +27.9% error.
• High correlations (r² = 0.58-0.96) were observed between model-estimated and probe-measured flow, with 84% of stages exceeding r² > 0.80.

Conclusions:

• The developed model accurately estimates and tracks changes in flow profiles and resulting SV.
• The method successfully operates without requiring recalibration, offering a significant clinical advantage.