Gas Mixing System for Medical Ventilator Oxygen Control
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Solution Overview
Problem
Medical ventilators are limited in their ability to deliver high oxygen concentrations, often restricted to ranges near 50% or lower, which is inadequate for patients requiring higher oxygen levels, such as those with conditions treated effectively by 95% or higher oxygen concentrations.
Innovation Solution
The system enhances oxygen concentration by actively controlling the pressure of an oxygen-filled plenum using a pressure sensor and control device to maintain a target pressure, ensuring that oxygen is efficiently mixed with ambient air and delivered to the ventilator's blower inlet, thereby increasing the oxygen concentration provided to the patient without overpressurizing the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If oxygen is added to enrich ambient air in ventilators, then oxygen concentration delivered to patients is improved, but the maximum oxygen concentration is limited to near 50% or lower
Solution Approach 1:
The system segments the gas delivery function into two separate inputs: one for ambient air and one for concentrated oxygen. By providing separate control pathways for air and oxygen mixing, the system can achieve oxygen concentrations greater than 50% by independently regulating the proportion of each gas source, thereby resolving the limitation of conventional single-source mixing.
2Productivity
If pressure control is implemented to maintain target pressure in oxygen plenum, then oxygen delivery efficiency is improved, but system complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The system implements a feedback control mechanism using a pressure sensor to monitor plenum pressure and automatically adjust the oxygen flow regulator. This closed-loop control maintains target pressure within the oxygen plenum, ensuring efficient oxygen delivery while preventing overpressurization. The automated feedback mechanism reduces manual intervention requirements despite the added sensor and control components.
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 solution allows for the delivery of higher oxygen concentrations to patients while minimizing oxygen wastage and maintaining the operational integrity of the ventilator, ensuring effective treatment for conditions requiring higher oxygen levels without risking overpressurization or control algorithm malfunctions.
Implementation Method 1
a pressure sensor coupled to the oxygen plenum. The pressure sensor is configured to measure a differential pressure between gas in the oxygen plenum and ambient air
Implementation Method 2
based on the measured differential pressure, generating a control signal to control the oxygen valve to maintain a target pressure of gas within the oxygen plenum
Implementation Method 3
a mixing valve. The mixing valve includes an oxygen inlet coupled to the oxygen plenum; an ambient-air inlet; and an outlet configured to be attached to an inlet of a blower of a ventilator
Data Source
AI summary
The present disclosure relates generally to medical devices and, more particularly, to a gas mixing system for a medical ventilator. A gas mixer is provided to adjust the oxygen concentration of environmental air for a blower-based ventilator, by adjusting the mix of air upstream of the ventilator and providing the mixed air to the ventilator's environmental air inlet.