Non-invasive Hemodynamic Assessment via Breathing Perturbations
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Solution Overview
Problem
Current methods for determining hemodynamic status in hemodynamically compromised patients are inadequate, particularly in non-invasively assessing fluid responsiveness and vascular tone, and fail to accurately predict the onset of hemodynamic congestion in heart failure, leading to delayed intervention.
Innovation Solution
A non-invasive system using mini-Mueller and mini-Valsalva controlled breathing activities or patient-initiated body position changes to create systematic perturbations in venous return, evaluated on a beat-to-beat basis, providing dynamic and static parameters for hemodynamic assessment without the need for invasive pressure monitoring or mechanical ventilation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If static measurement parameters (right atrial pressure, pulmonary artery occlusion pressure, cardiac output) are used to evaluate volume status, then hemodynamic measurements are obtained, but these parameters are not reliable predictors of fluid responsiveness
Solution Approach 1:
The patent transitions from using static hemodynamic parameters (right atrial pressure, pulmonary artery occlusion pressure, cardiac output) to dynamic parameters that capture temporal variations. Specifically, it measures beat-to-beat changes in stroke volume, heart rate, and blood pressure during controlled breathing maneuvers (mini-Mueller, mini-Valsalva) to predict fluid responsiveness, thereby improving measurement precision beyond static values
Solution Approach 2:
The invention employs dynamic assessment methods where patients perform controlled breathing maneuvers to induce transient hemodynamic changes. By analyzing the dynamic response of stroke volume, heart rate, and blood pressure during these maneuvers, the system captures functional information about cardiac preload dependency that static measurements cannot provide, improving fluid responsiveness prediction
2Measurement precision
If dynamic indices (systolic pressure variation, pulse pressure variation, stroke volume variation) are used to predict fluid responsiveness, then prediction accuracy improves for mechanically ventilated patients, but these indices are not accurate in spontaneously breathing patients
Solution Approach 1:
The patent develops a universal assessment method that works across different breathing modes (mechanical ventilation and spontaneous breathing). By using controlled breathing maneuvers (mini-Mueller, mini-Valsalva) that can be performed by any patient regardless of their baseline breathing mode, the system achieves fluid responsiveness prediction accuracy comparable to dynamic indices in mechanically ventilated patients while extending applicability to spontaneously breathing patients
Solution Approach 2:
The system performs preliminary controlled breathing maneuvers (mini-Mueller, mini-Valsalva) before making fluid responsiveness predictions. These maneuvers proactively induce controlled hemodynamic perturbations that allow the system to measure dynamic responses and calculate prediction metrics, ensuring accurate assessment regardless of the patient's spontaneous breathing status
3Reliability
If invasive pressure monitoring or mechanical ventilation is required for accurate hemodynamic assessment, then measurement reliability improves, but device complexity and patient comfort deteriorate
Solution Approach 1:
The patent replaces invasive mechanical monitoring systems (arterial lines, pulmonary artery catheters, mechanical ventilators) with non-invasive optical and acoustic sensors. By using photoplethysmography (PPG) for stroke volume detection, phonocardiography (PCG) for heart sound analysis, and pulse transit time (PTT) measurements, the system achieves hemodynamic assessment accuracy previously only attainable through invasive methods, while eliminating the need for complex invasive equipment
Solution Approach 2:
The system creates non-invasive copies of invasive measurement capabilities. Using PPG waveforms to estimate stroke volume changes, PCG to detect cardiac events, and PTT to assess arterial stiffness, the patent replicates the information obtained from invasive pressure monitoring without requiring physical intrusion into the cardiovascular system, thereby maintaining reliability while reducing device complexity
4Productivity
If fluid administration is increased to improve cardiac output in hypovolemic patients, then cardiac output may increase in volume responders, but fluid overload can occur in volume non-responders leading to right ventricular overload and pulmonary edema
Solution Approach 1:
The patent implements a feedback-based fluid management system that continuously monitors dynamic hemodynamic parameters (stroke volume variation, heart rate response, blood pressure changes) during controlled breathing maneuvers. By analyzing the patient's real-time physiological response to these maneuvers, the system provides feedback guidance on whether fluid administration is likely to benefit the patient, enabling personalized fluid therapy decisions that improve cardiac output in volume responders while avoiding fluid overload in volume non-responders
Data Source
AI summary
Embodiments of the present invention provide reliable, convenient, and cost-effective methods and apparatuses to determine the hemodynamic status of the patent. The methods and apparatuses provide for the noninvasive determine of hemodynamic status by using systematic perturbations of venous return or trend observation over time. Embodiments do not require invasive pressure monitoring or the use of ventilator but instead can be an entirely noninvasive system.