Pressure Adjustment Apparatus for Inflatable Cuffs
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Solution Overview
Problem
Existing pressure adjustment systems for inflatable cuffs, such as those used in endotracheal tubes, face challenges in making quick and precise adjustments and are orientation-dependent, leading to inefficiencies and potential leaks.
Innovation Solution
A pressure adjustment apparatus comprising a pump with a variable volume and a selector valve that allows for precise control of fluid flow through check valves, enabling quick adjustments and orientation-independent pressure monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large sleeve internal volume is used to inflate the occlusion cuff with less than one full stroke, then the ability to inflate the cuff quickly is improved, but the ability to make fine adjustments to fluid pressure deteriorates
Solution Approach 1:
The fluid delivery system is segmented into multiple chambers (first chamber and second chamber) with separate control mechanisms. The first chamber handles gross inflation with larger volume capacity, while the second chamber provides fine pressure adjustments with smaller volume increments, allowing independent control of each function
Solution Approach 2:
The system dynamically switches between different delivery mechanisms based on the inflation stage. During initial inflation, the system uses the first chamber for rapid fluid delivery. As the cuff approaches target pressure, the system transitions to the second chamber for precise incremental adjustments, optimizing both speed and precision at different operational phases
2Quantity of substance
If the fluid necessary to inflate the occlusion cuff exceeds the volume within the sleeve, then the hypodermic manometer may need to be uncoupled to refill the sleeve, but this impairs the user's ability to make quick changes to cuff pressure
Solution Approach 1:
The fluid storage and delivery system is divided into multiple chambers. The first chamber serves as a primary reservoir for bulk fluid storage, while the second chamber acts as a secondary reservoir that can be refilled without disconnecting the device. This segmentation allows continuous operation where the second chamber can be replenished from an external source while maintaining coupling to the cuff
Solution Approach 2:
The system performs preliminary refilling of the second chamber during periods when fine adjustments are not needed, preparing fluid in advance. The check valves prevent backflow during this refilling process, allowing the operator to top up the second chamber from an external source without disconnecting the device from the cuff, thus maintaining readiness for quick pressure changes
3Measurement precision
If a hypodermic manometer is used for pressure indication, then pressure monitoring is possible, but the accuracy depends upon orientation with respect to gravity
Solution Approach 1:
The traditional gravity-dependent hypodermic manometer is replaced with a pressure sensor that uses electronic transduction to measure pressure. This sensor converts pressure into an electrical signal that can be displayed on a screen, eliminating dependence on gravitational orientation and allowing accurate pressure monitoring in any position
Solution Approach 2:
The integrated display unit serves multiple functions: it displays pressure readings from the sensor, provides visual feedback on cuff inflation status, and can alert the operator to abnormal pressure conditions. This multi-functional device replaces the single-function hypodermic manometer while adding orientation independence through electronic sensing
4Measurement precision
If a bellows is used in the hypodermic manometer, then pressure measurement is enabled, but a rupture or leak poses the risk of mixing manometer fluid with fluid in contact with the occlusive cuff
Solution Approach 1:
The mechanical bellows system is replaced with an electronic pressure sensor that directly measures pressure without requiring a sealed fluid-filled chamber. This eliminates the bellows component that could rupture or leak, removing the pathway for fluid mixing between the manometer system and the cuff inflation system
Solution Approach 2:
An incompressible fluid (such as oil or silicone) is introduced as an intermediary medium in the pressure transmission line between the cuff and the sensor. This fluid transmits pressure accurately while being chemically inert and non-mixing with both the cuff fluid and any internal sensor fluids, preventing contamination even if seals are compromised
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 system allows for precise and quick adjustments of pressure within inflatable cuffs, independent of orientation, reducing the risk of leaks and improving user control over cuff pressure.
Implementation Method 1
a first check valve disposed in a first fluid channel of the plurality of fluid channels, the first check valve being oriented to permit flow through the first fluid channel only in a first flow direction, the first flow direction being a flow direction out of the variable volume
Implementation Method 2
a third check valve disposed in a third fluid channel of the plurality of fluid channels, the third check valve being oriented to permit flow through the third fluid channel only in a second flow direction, the second flow direction being a flow direction into the variable volume
Data Source
AI summary
A pressure adjustment apparatus including a pump, a selector valve coupled to the pump, and a chamber in selective fluid communication with the pump through the selector valve is disclosed. The pump includes a pump body that defines a variable volume therein, the pump body further defining a first aperture and a second aperture therethrough. The selector valve includes a first check valve disposed in a first fluid channel of a plurality of fluid channels, the first check valve being oriented to permit flow through the first fluid channel only in a first flow direction, the first flow direction being a flow direction out of the variable volume, and a second check valve disposed in a second fluid channel of the plurality of fluid channels, the second check valve being oriented to permit flow through the second fluid channel only in a second flow direction.