Sphygmomanometer Fluid Circuit Control for Blood Pressure Accuracy
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Solution Overview
Problem
The accuracy of blood pressure measurements using conventional sphygmomanometers is affected by the varying amount of air remaining in the sensing cuff between measurements, due to differences in cuff wrapping tightness, which impacts the reliability of subsequent readings.
Innovation Solution
A sphygmomanometer with a control unit that manages a fluid circuit to discharge remaining air from the sensing cuff, store a predetermined amount of pressure-transmitting fluid, and then compress the measurement site using an oscillometric method, ensuring consistent fluid volume for accurate blood pressure calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sensing cuff is wrapped around the measurement target site, then the sphygmomanometer can be worn and used for blood pressure measurement, but the amount of air remaining in the sensing cuff varies depending on wrapping tightness, which deteriorates measurement accuracy
Solution Approach 1:
The control unit executes discharge processing before blood pressure measurement to remove air remaining in the sensing cuff. This preliminary action ensures that the sensing cuff starts with a consistent fluid volume state, eliminating the variability caused by different wrapping tightness and ensuring accurate measurements.
Solution Approach 2:
The system uses pressure detection to monitor the state of air in the sensing cuff and automatically triggers discharge processing when air is detected. This feedback mechanism ensures that the sensing cuff maintains the correct fluid volume state, resolving the contradiction between wearing convenience and measurement accuracy.
2Measurement precision
If air is discharged from the sensing cuff before measurement, then measurement accuracy is improved, but the operation complexity increases due to additional preparation steps
Solution Approach 1:
The control unit automatically detects air in the sensing cuff using pressure sensors and executes discharge processing without user intervention. The system serves itself by monitoring its own state and performing necessary adjustments, which improves measurement accuracy while keeping the user interface simple.
Solution Approach 2:
The system discards excess air from the sensing cuff through controlled discharge processing. By automatically removing the harmful element (excess air) before measurement, the system ensures accurate readings without requiring complex manual preparation procedures.
3Reliability
If a predetermined amount of pressure transmitting fluid is stored in the sensing cuff, then measurement reliability is improved, but the time required for preparation increases
Solution Approach 1:
The control unit stores a predetermined amount of pressure transmitting fluid in the sensing cuff before blood pressure measurement. This preliminary action ensures that the sensing cuff is properly prepared with the correct fluid volume, improving measurement reliability while minimizing preparation time through automated control.
Solution Approach 2:
The system controls the volume of pressure transmitting fluid in the sensing cuff by adjusting the discharge timing and duration. By precisely controlling this parameter, the system achieves reliable measurements without requiring excessive preparation time.
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 ensures accurate blood pressure measurements by consistently managing the fluid volume in the sensing cuff, reducing the impact of cuff wrapping variations and improving measurement reliability.
Implementation Method 1
a sensing cuff arranged in a worn state of the belt being worn around the measurement target site, at a portion of an inner circumferential side of the belt that crosses an artery passing portion of the measurement target site, and configured in a bag shape so as to allow storage of a pressure transmitting fluid
Implementation Method 2
a main body mounted with a pump
Implementation Method 3
calculates a blood pressure of the measurement target site based on a pressure of the pressure transmitting fluid stored in the sensing cuff by an oscillometric method
Data Source
AI summary
The present invention provides a sphygmomanometer that can create, before measuring a blood pressure, a state for making a blood pressure measurement accurate. A sphygmomanometer includes a fluid circuit and a control unit. The control unit has a first preparation processing unit, a second preparation processing unit, and a measurement processing unit which operate in a worn state of the sphygmomanometer. The first preparation processing unit operates a pressing cuff to discharge remaining fluid in a sensing cuff to the atmosphere through the fluid circuit. Then, the second preparation processing unit causes the sensing cuff to store a predetermined amount of pressure transmitting fluid received from a pump through the fluid circuit. Subsequently, the measurement processing unit operates the pressing cuff and calculates the blood pressure by the oscillometric method based on pressure of the pressure transmitting fluid stored in the sensing cuff.