Respiratory Device Rainout Protection Control

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Solution Overview

Problem

Existing ventilation devices struggle to maintain accurate and stable artificial ventilation with correctly humidified breathing gas without condensation in the patient interface, especially under extreme external conditions such as low temperatures and high altitudes, due to the lack of heating and sensors in disposable patient interfaces, which can lead to condensation and reduced measurement accuracy.

Innovation Solution

The ventilation device incorporates a control system that monitors operating parameters like temperature, flow rate, and relative humidity to determine the risk of condensation in the patient interface and adjusts the evaporation device's performance to prevent condensation, using a data memory to link operating parameters with condensation likelihood and adjusting the evaporation device's power based on this information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the evaporation device operates at high performance to maintain target humidity, then the humidity of respiratory gas is improved, but condensation occurs in the patient interface

Engineering Contradiction:
Improvehumidity of respiratory gasVSAvoidcondensation in patient interface
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The control device predicts the follow-up state (temperature and humidity) of the respiratory gas in the patient interface before the gas actually reaches the patient. Based on this prediction, the control device adjusts the evaporation device performance in advance to prevent condensation, rather than reacting after condensation occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control device uses sensors to detect actual temperature, humidity, and flow rate in the respiratory gas line. These measurements feed back to the control device, which compares them against predicted values and adjusts the evaporation device performance accordingly to maintain optimal humidity without causing condensation.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If the patient interface is made disposable and simplified, then ease of operation and hygiene are improved, but heating and sensing capabilities are lost

Engineering Contradiction:
Improvedisposable patient interfaceVSAvoidtemperature control in patient interface
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The disposable patient interface is designed to work passively with the reusable breathing gas line assembly. The heating and sensing functions are concentrated in the reusable portion, while the disposable interface focuses on patient contact and basic gas delivery. This division allows the simple disposable interface to benefit from the sophisticated temperature and humidity control of the reusable assembly.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The reusable breathing gas line assembly acts as an intermediary between the ventilator and the disposable patient interface. It carries the heated and humidified respiratory gas from the ventilator to the patient interface, maintaining temperature and humidity control through its insulated construction and integrated sensors, while the disposable interface remains simple.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If the breathing gas line assembly is insulated to maintain temperature, then temperature stability is improved, but condensation risk increases without active control

Engineering Contradiction:
Improvetemperature stability of respiratory gasVSAvoidcondensation in breathing gas line
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The control device dynamically adjusts the performance parameters of the evaporation device based on detected and predicted temperature, humidity, and flow rate conditions. By changing the evaporation rate in response to varying conditions, the system maintains optimal humidity levels without creating excess moisture that would condense in the insulated breathing gas line assembly.

Inventive Principle:
Principle #35Parameter changes

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 effectively prevents condensation in the patient interface, ensuring stable and accurate artificial ventilation by dynamically adjusting the evaporation device's performance according to the predicted condensation risk, thereby maintaining optimal breathing gas conditions for the patient.

Implementation Method 1

a variable-capacity evaporation device which is designed to increase the absolute humidity of the inspiratory respiratory gas stream

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

a heatable breathing gas line arrangement in order to prevent undesired condensation of moisture in the breathing gas by supplying heat to the breathing gas line arrangement

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

If the delivered breathing gas is too humid, water may condense from the breathing gas and enter the patient's lungs in liquid form

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3843821B1Respiratory device with rainout protection in the patient interface
Publication Date: 2024.04.03 HAMILTON MEDICAL AG
  • EP3843821B1 patent drawingFigure 1
  • EP3843821B1 patent drawingFigure 2

AI summary

The invention relates to a respiratory device (10) for the artificial respiration of a patient (12), comprising: - a respiration gas source assembly (15, 62), - a flow-changing device (16), - a humidifier device (38) which is designed to increase the value of the absolute humidity of the inspiratory respiration gas flow (AF), said humidifier device (38) having a liquid store (40) and an evaporation device (76) with a variable output for this purpose, - a respiration gas line assembly (30) in order to convey the inspiratory respiration gas flow (AF) from the dehumidifying device (38) to the patient (12), - a flow sensor (44) which detects the value of the respiration gas flow (AF), and - a controller (18) which is designed to control the operational output of the evaporation device (76) depending on a specified target humidity of the respiration gas and depending on signals of the flow sensor (44), the proximal end (30a) of said respiration gas line assembly (30) having a coupling formation (44a) for coupling the respiration gas line assembly (30) to a patient interface (31) that transfers respiration gas to the patient (12). According to the invention, the controller (18) is designed to detect a sequence state of the respiration situation downstream of the coupling formation (44a) in the inspiratory direction depending on operational parameters of the respiratory device (10) and change the operational output of the evaporation device (76) depending on the result of the detection.