Breathing Circuit AC Waveform Control for Humidity Sensing

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Solution Overview

Problem

Existing gas humidification systems struggle to maintain optimal temperature and humidity levels in respiratory circuits, particularly when the conduit passes through distinct temperature environments, leading to condensation or overheating issues.

Innovation Solution

A controller for a breathing assistance apparatus that controls AC power to heater wires and sensor readings at specific zero crossings of the AC waveform, allowing precise temperature and humidity regulation in segmented conduits, with sensors positioned at or near the patient end to minimize interference and enhance accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If respiratory circuits are shared between patients during transport, then resource utilization and cost efficiency are improved, but the risk of cross-contamination and infection transmission increases

Engineering Contradiction:

Improverespiratory circuit reuseVSAvoidcross-contamination risk

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical/physical cleaning methods with automated chemical dispensing systems that apply cleaning solutions and barriers through programmed sequences, enabling consistent decontamination of shared respiratory circuits between patients

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system enables the respiratory circuit to be automatically decontaminated and prepared for the next patient through automated dispensing of cleaning solutions and application of barriers, reducing manual intervention and ensuring consistent cleaning protocols are followed

Inventive Principle:

Principle #25Self-service

2Object-affected harmful factors

If complex cleaning and decontamination protocols are implemented for shared circuits, then infection control is improved, but the time required for patient turnover and device complexity increases

Engineering Contradiction:

Improveinfection controlVSAvoidpatient turnover time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The system implements periodic automated cleaning cycles with predetermined sequences of dispensing different cleaning solutions at specific intervals, ensuring thorough decontamination while maintaining consistent timing that optimizes patient turnover

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system performs preliminary dispensing of cleaning solutions and application of barriers before the next patient connection is required, ensuring the circuit is fully decontaminated and ready for immediate use, thereby minimizing patient turnover time

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3487567B1Controller for a breathing assistance apparatus

Publication Date: 2026.04.29 FISHER & PAYKEL HEALTHCARE LTD

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AI summary

Some embodiments provide a breathing assistance apparatus comprising a conduit for conveying gases therein, the conduit comprising circuitry. The circuitry may comprise at least one heater wire part to heat gases in the conduit, in use, and at least one sensor wire part comprising at least one sensor for monitoring a parameter of the gases in the conduit. There is also provided a controller to control provision of AC power or AC voltage to the heater wire part; and control selective reading of the sensor. The controller may be configured to read the sensor at or about a particular portion of the AC power waveform provided to the heater wire part.