Sinewave Indicator Gas Measurement for Cardiopulmonary Parameters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods fail to simultaneously and non-invasively measure cardiopulmonary parameters such as anatomical dead space, functional residual capacity, pulmonary blood flow, and lung inhomogeneity, especially for ventilated patients, due to limitations in rebreathing techniques and uniform concentration assumptions.
Innovation Solution
The inspired sinewave technique, which controls the concentration of an indicator gas to follow a sinewave pattern, measures flow rates and concentrations during inspiration and exhalation, fitting sinewave envelopes to determine anatomical dead space and other parameters using a conservation-of-mass principle, accommodating non-uniform concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rebreathing techniques are used to measure cardiopulmonary parameters, then pulmonary blood flow can be measured non-invasively, but the method cannot be used for ventilated patients and requires complex bag systems
Solution Approach 1:
The patent changes the fundamental parameter of gas concentration delivery from uncontrolled rebreathing to controlled sinewave patterns. By delivering indicator gas at controlled concentrations following sinewave patterns, the system achieves accurate measurement of pulmonary blood flow and other parameters while being compatible with ventilated patients, eliminating the need for bag systems.
Solution Approach 2:
The patent employs periodic sinewave patterns for delivering indicator gas concentrations. This periodic action allows the system to create measurable concentration variations that can be tracked through the respiratory system, enabling continuous measurement of cardiopulmonary parameters including pulmonary blood flow without requiring rebreathing bags.
2Device complexity
If uniform concentration assumptions are made in measurement methods, then calculations are simplified, but measurement accuracy deteriorates due to non-uniform actual concentrations
Solution Approach 1:
The patent implements feedback control by continuously measuring actual indicator gas concentrations and using these measurements to inform subsequent calculations. The system measures flow rates and concentrations, fits sinewave envelopes to the data, and uses this feedback information to accurately determine anatomical dead space and other parameters, eliminating the need for unrealistic uniform concentration assumptions.
Solution Approach 2:
The patent transitions from static uniform concentration assumptions to dynamic sinewave pattern delivery with actual concentration measurement. By dynamically adjusting and measuring actual concentrations throughout the breathing cycle, the system achieves accurate measurements while maintaining manageable calculation complexity through envelope fitting techniques.
3Productivity
If multiple cardiopulmonary parameters are measured simultaneously, then comprehensive patient monitoring is achieved, but measurement continuity and accuracy for ventilated patients becomes difficult
Solution Approach 1:
The patent creates a universal measurement system that can simultaneously measure multiple cardiopulmonary parameters including anatomical dead space, functional residual capacity, pulmonary blood flow, and lung inhomogeneity. The sinewave-based approach with flow rate and concentration measurements provides a multi-functional platform that works reliably for both ventilated and non-ventilated patients, achieving comprehensive monitoring with continuous measurement capability.
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 method provides accurate and continuous measurements of cardiopulmonary parameters, including lung inhomogeneity, for ventilated patients, outperforming previous methods by reducing errors and improving repeatability, as demonstrated in mechanical bench lung setups.
Implementation Method 1
the concentration of the indicator gas being controlled such as to follow a sinewave pattern over successive breaths
Implementation Method 2
calculating the anatomical dead space... by applying a conservation-of-mass principle
Data Source
AI summary
Methods and systems for adjusting ventilator settings in a patient based on information obtained by measuring anatomical dead space VD in a lung are provided utilizing controlled indicator gas delivery over multiple breaths, including related measurements and calculations of lung inhomogeneity, functional residual capacity, avelolar volume VA, dead space VD, and pulmonary blood flow {dot over (Q)}P.