Indicator Dilution Measurement Correction for Branch Volumes
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Solution Overview
Problem
Current indicator dilution measurement methods, such as thermodilution, face challenges when the site of injection and detection are not near the right atrium or left ventricle, leading to errors in calculating cardiac output and global end-diastolic volume due to additional volumes and delays in the circulation, particularly in patients with conditions like arterio-venous shunts or aortic aneurysms, resulting in incorrect therapeutic decisions.
Innovation Solution
A method and device that corrects for additional volumes and delays by defining specific additional volumes and branches between the injection and detection sites, using anthropometric data and imaging to estimate these volumes, and applying convolution to a hypothetical unbranched model to calculate corrected mean transit times and cardiac filling volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If indicator dilution measurement is performed with remote injection and detection sites, then the method can be applied to more patient positions and access sites, but measurement precision deteriorates due to additional volumes and delays in the circulation branches
Solution Approach 1:
The circulation system is segmented into a central volume (heart and lungs) and multiple additional volumes (branches). The method separately calculates and corrects for the volumes and delays in each branch, allowing remote injection and detection sites while maintaining measurement precision through systematic decomposition of the circulation pathway.
Solution Approach 2:
Additional volume and delay parameters are introduced as intermediary correction factors. These parameters mediate between the raw measurement data from remote sites and the true central volumetric parameters, compensating for the effects of branch volumes and delays to restore measurement accuracy.
2Device complexity
If additional volumes and delays in branches are not corrected, then the measurement system remains simple, but calculation accuracy of central cardiopulmonary volumes deteriorates
Solution Approach 1:
The method performs preliminary calculations of additional volumes and delays using anthropometric data and imaging before the main measurement. These pre-calculated correction factors are then applied to the indicator dilution measurement, allowing accurate central volumetric parameter calculation while keeping the core measurement system relatively simple.
Solution Approach 2:
The method changes the parameters used in the measurement system by introducing additional volume and delay parameters that can be calculated from anthropometric data and imaging. These parameter changes enable correction for branch effects without fundamentally altering the indicator dilution measurement approach, balancing system simplicity with calculation accuracy.
3Measurement precision
If correction for additional volumes and delays is applied, then measurement precision for central volumes is improved, but device complexity increases due to additional calculations and data requirements
Solution Approach 1:
The method uses copying of anthropometric data and imaging information to create virtual models of the circulation system. These digital copies allow calculation of additional volumes and delays without requiring physical measurement of each branch, reducing the complexity of data collection while maintaining correction accuracy.
Solution Approach 2:
The method replaces direct mechanical measurement of branch volumes with computational calculations based on anthropometric data and imaging. This substitution reduces the complexity of physical measurement and data collection requirements while maintaining the ability to accurately correct for branch effects in the circulation system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for precise calculation of central cardiopulmonary volumes, eliminating errors introduced by branch volumes and delays, enabling accurate assessment of cardiac filling volumes even in complex anatomical conditions or extracorporeal setups.
Implementation Method 1
the cold indicator mainly diffuses into and penetrates these spaces via convection and diffusion
Implementation Method 2
the cold indicator mainly diffuses into and penetrates these spaces via convection and diffusion
Implementation Method 3
The warm blood following (subsequent to) the cold bolus again washes out the cold indicator from the pulmonary extravascular space
Implementation Method 4
applying convolution to a hypothetical unbranched model to calculate corrected mean transit times
Data Source
AI summary
The invention relates to indicator dilution measurements of a central volume (V1) with a first site of injection (S1) upstream of the central volume (V1) a second site of detection (S2) of the diluted indicator downstream of the central volume (V1), wherein a first additional volume (V2) is defined between the first site (S1) and the central volume (V1) and a first additional branch (B2) is defined between the first site (S1) and the central volume (V1) and wherein a second additional volume (V3) is defined between the central volume (V1) and the second site (S2) and a second additional branch (B3) is defined between the central volume (V1) and the second site (S2) wherein a result of central volumetric parameters are corrected for the first and second additional volumes (V2, V3) and/or for the first and second additional branches (B2, B3).