Blood Volume Correction for NIRS Mitochondrial Capacity
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Solution Overview
Problem
Near-infrared spectroscopy (NIRS) measurements of skeletal muscle oxygen consumption are inaccurate due to changes in blood volume during arterial occlusions, which skew the measurements of oxygenated and deoxygenated hemoglobin/myoglobin signals.
Innovation Solution
A system and method that calculates a blood volume correction factor to adjust the NIRS signals, ensuring a 1:1 ratio between oxygenated and deoxygenated hemoglobin/myoglobin changes, thereby accurately reflecting mitochondrial oxygen consumption, using three approaches: a global correction factor for resting occlusions, individualized correction factors for each occlusion, and an iterative method to minimize error in recovery curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If arterial occlusion is applied to measure skeletal muscle oxygen consumption using NIRS, then oxygen consumption can be measured noninvasively, but blood volume changes occur that skew the measurements
Solution Approach 1:
The system continuously monitors blood volume changes during arterial occlusion and uses this feedback to dynamically adjust the NIRS signal interpretation. The blood volume correction factor is calculated based on real-time tHb measurements and applied to correct the oxygenated and deoxygenated hemoglobin signals, ensuring accurate oxygen consumption measurements despite ongoing blood volume fluctuations.
Solution Approach 2:
The invention changes the measurement parameter by introducing a blood volume correction factor (β) that transforms the raw NIRS signals into corrected signals. This parameter adjustment allows the system to compensate for blood volume changes and extract accurate oxygen consumption data from the altered signal conditions during arterial occlusion.
2Ease of operation
If NIRS device is used instead of MRS equipment, then device portability and ease of use improve, but measurement accuracy deteriorates due to blood volume changes
Solution Approach 1:
The blood volume correction factor acts as an intermediary that mediates between the NIRS device's inherent limitations and the requirement for accurate measurements. This correction factor translates the blood volume changes into a mathematical adjustment that compensates for the artifact, allowing portable NIRS devices to achieve accuracy comparable to expensive MRS equipment.
Solution Approach 2:
The invention replaces the need for complex mechanical MRS equipment with a simpler NIRS-based system that uses optical detection combined with mathematical correction. By substituting the mechanical complexity of MRS with optical sensing and computational correction, the system achieves similar measurement accuracy with portable, easy-to-use equipment.
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
The blood volume correction methods provide accurate and reliable measurements of mitochondrial capacity by ensuring symmetry in oxygenated and deoxygenated signal changes, improving the reliability and reproducibility of NIRS-based assessments of skeletal muscle oxygen consumption.
Implementation Method 1
Near-infrared spectroscopy (NIRS) also provides a noninvasive measure of muscle oxygenation
Implementation Method 2
measurements are then taken with the NIRS device to quantify the oxygen that is being consumed by the muscle
Data Source
AI summary
In one embodiment, measuring mitochondrial capacity includes performing arterial occlusions on a patient, measuring oxygenated hemoglobin/myoglobin and deoxygenated hemoglobin/myoglobin within the patient's body during the occlusions, calculating a blood volume correction factor that accounts for a change in blood volume that occurs during the arterial occlusions, and applying the correction factor to the measured oxygenated hemoglobin/myoglobin and deoxygenated hemoglobin/myoglobin measurements to obtain correct oxygenated hemoglobin/myoglobin and deoxygenated hemoglobin/myoglobin measurements.