Anesthesia Gas Verification via Density Measurement

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Solution Overview

Problem

Current anesthesia gas flow control systems fail to accurately verify the identity of oxygen and nitrous oxide gases, leading to potential oxygen deprivation in patients due to improper crossover or cross-connection of supply lines.

Innovation Solution

An apparatus and method that analyze the characteristics of gases delivered via gas lines by using a sampling technique to measure the leak time of gases from a designated chamber, distinguishing between oxygen and nitrous oxide based on their different densities and leak rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional failsafe components are used to measure gas pressure or flow in the oxygen line, then the system can detect the presence of gas flow, but the system cannot verify the identity of the gas (whether it is actually oxygen)

Engineering Contradiction:
ImproveGas identity verificationVSAvoidVerification system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the measurement parameter from simple pressure/flow detection to density-based verification. By measuring the density of the gas in the oxygen line (comparing actual density against expected oxygen density), the system can verify gas identity rather than merely detecting presence. This resolves the contradiction by providing accurate gas identification without requiring complex spectral analysis or chemical sensing systems.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical failsafe components with a density measurement system that uses pressure and temperature readings to calculate gas density. This substitution enables identity verification while maintaining relatively simple system architecture, avoiding the need for complex mechanical verification mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If different and incompatible gas fittings are designed for oxygen and nitrous oxide supply lines to identify and restrict different gas sources, then gas identification is improved, but the system fails if a user mistakenly installs an oxygen fitting onto a nitrous oxide supply hose

Engineering Contradiction:
ImproveGas line connection safetyVSAvoidFitting installation correctness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements preliminary verification by measuring the density of gas in the oxygen line before allowing the anesthesia system to operate. This preliminary check ensures that the correct gas is connected and flowing, preventing the harmful effect of incorrect gas delivery even if wrong fittings are used. The system verifies gas identity proactively rather than relying solely on physical fitting compatibility.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces feedback by continuously monitoring gas density in the oxygen line and comparing it against expected values. If the density indicates incorrect gas (such as nitrous oxide in the oxygen line), the system provides feedback through alarms or shutdowns, preventing unsafe operation. This feedback mechanism compensates for potential fitting installation errors.

Inventive Principle:
Principle #23Feedback

3Productivity

If the flowmeter treats any gas in the oxygen intake as oxygen and delivers it to the patient, then the system operates continuously, but oxygen deprivation occurs when non-oxygen gas is delivered

Engineering Contradiction:
ImproveAnesthesia delivery continuityVSAvoidOxygen deprivation risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent performs preliminary verification of gas identity by measuring density in the oxygen line before the gas is delivered to the patient. This preliminary check ensures that only verified oxygen (or acceptable alternative) reaches the patient, eliminating the harmful effect of oxygen deprivation while maintaining system productivity through automated verification.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces density measurement as an intermediary verification step between gas delivery and patient administration. This intermediary check confirms gas identity without interrupting the overall anesthesia delivery process, allowing continuous operation while preventing harmful gas delivery through automated density-based verification.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Effectively verifies the correct identification of oxygen and nitrous oxide gases, preventing accidental delivery of incorrect gases and ensuring patient safety by triggering system shutdowns or alerts in case of abnormal conditions.

Implementation Method 1

distinguishing between oxygen and nitrous oxide based on their different densities and leak rates

Methodology Applied
Scientific EffectDensity difference:

Implementation Method 2

measure the leak time of gases from a designated chamber

Methodology Applied
Scientific EffectGas leak rate:

Data Source

PatentEP4164718B1Oxygen line verification for anesthesia gas flow controls
Publication Date: 2025.06.11 HU FRIEDY MFG CO INC
  • EP4164718B1 patent drawingFigure 1
  • EP4164718B1 patent drawingFigure 2
  • EP4164718B1 patent drawingFigure 3

AI summary

Various examples disclosed relate to an apparatus and method for use in verifying input gas, such as differences between a first and a second gas in an anesthesia flow control where one of the gases is oxygen gas and the other of the gases is nitrous oxide gas. The apparatus can include, for example, a chamber having an inlet to receive gas and a vent to exhaust the gas, a gas control to fill the chamber with the gases to a determined begin pressure, and a microprocessor configured to measure respective times to exhaust the first gas and the second gas from the chamber, via the vent, to reach a determined end pressure. Based on time to exhaust the respective gases, a difference between the first and second gases can be identified; this verification can verify that improper crossover/cross-connection of gas supply lines is not present.