Shutter Occlusion for Accurate Lung Volume Measurement
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Solution Overview
Problem
Current methods for measuring pulmonary function parameters, such as lung volumes and alveolar pressure, are inaccurate due to prolonged equilibration of mouth and alveolar pressure, leading to misdiagnosis of pulmonary disorders, especially in patients with airway obstruction or flow limitation.
Innovation Solution
A method and device that interrupt respiration with a rapid occlusion event in an airflow chamber, allowing for precise measurement of airflow rate and pressure changes to determine pulmonary volume changes and alveolar pressure, using a shutter mechanism and sensors to facilitate accurate data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If gas dilution method is used to measure FRC, then the measurement can be performed with simpler equipment, but the measurement accuracy deteriorates in subjects with poor gas mixing due to disease
Solution Approach 1:
The patent uses a shutter as an intermediary device to rapidly occlude the airway, creating a controlled interruption that allows measurement of alveolar pressure and lung volumes. This intermediary mechanism enables accurate measurements in diseased subjects by preventing the gas mixing problems that plague conventional dilution methods.
Solution Approach 2:
The patent employs periodic shutter occlusions during the respiratory cycle to obtain measurements. By intermittently blocking the airway at specific phases of breathing, the system can capture pressure and volume data without requiring continuous complex monitoring, thus maintaining simplicity while improving accuracy.
2Measurement precision
If whole body plethysmography is used to measure TGV, then the measurement accuracy is maintained even in sick subjects, but the device complexity and cost increase significantly
Solution Approach 1:
The patent extracts the essential measurement function from the complex whole body plethysmograph by using a simple shutter occlusion technique. Instead of requiring the subject to be in a sealed chamber with multiple sensors, the invention isolates the critical measurement moment (during shutter occlusion) and measures only the necessary parameters (airflow rate and pressure changes), thereby achieving accurate TGV measurement with minimal equipment.
Solution Approach 2:
The patent replaces the complex mechanical system of whole body plethysmography with a simpler approach using electronic sensors to detect pressure changes and airflow rate. The shutter mechanism provides the necessary occlusion, while electronic detection systems replace the complex mechanical measurement apparatus, reducing overall system complexity while maintaining measurement accuracy.
3Ease of operation
If prolonged equilibration is allowed for pressure measurement, then the measurement process is simpler, but the diagnostic accuracy deteriorates due to errors in patients with airway obstruction
Solution Approach 1:
The patent performs preliminary action by rapidly occluding the airway with a shutter before pressure equilibration can occur. This preliminary occlusion captures the pressure and airflow data at the precise moment before equilibrium is established, preventing the measurement errors that arise from prolonged equilibration in obstructed airways.
Solution Approach 2:
The patent skips the prolonged equilibration phase entirely by rapidly measuring pressure and airflow rate immediately during shutter occlusion. By rushing through the measurement process before equilibration can cause errors, the system maintains both operational simplicity and diagnostic accuracy, particularly for patients with airway obstruction.
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 enables accurate determination of lung volumes and alveolar pressure, reducing errors associated with prolonged equilibration and improving diagnostic accuracy for pulmonary disorders.
Implementation Method 1
interrupting the respiration event by an occlusion of the airflow chamber initiated at a first time instant and terminated at a second time instant
Implementation Method 2
taking a plurality of measurements of airflow rate through the airflow chamber between the second time instant and a third time instant
Implementation Method 3
determining a pulmonary volume change substantially equal to a reduction of a pulmonary air volume by a pulmonary response air volume and a normal air volume, wherein the pulmonary volume change is related to a change in density of air in the airflow chamber
Data Source
AI summary
A method for determining a pulmonary volume change includes: receiving a respiration event from a subject in an airflow chamber; interrupting the respiration event by an occlusion of the airflow chamber initiated at a first time instant and terminated at a second time instant subsequent to the first time instant; taking a plurality of measurements of airflow rate through the airflow chamber between the second time instant and a third time instant subsequent to the second time instant; and determining a pulmonary volume change substantially equal to a reduction of a pulmonary air volume by a pulmonary response air volume and a normal air volume, wherein the pulmonary volume change is related to a change in density of air in the airflow chamber.