Medical airway temperature sensor

• Main Author: MALCOLM DAVID SMITH
• Format: Patent
• Language: English
• Published: 11.05.1994
• Edition: 5
• Subjects: ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVEREDIN A SINGLE OTHER SUBCLASS; DIAGNOSIS; HUMAN NECESSITIES; HYGIENE; IDENTIFICATION; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT; MEASURING; MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION,OR SHOCK; MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR; MEASURING QUANTITY OF HEAT; MEASURING TEMPERATURE; MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL; MEDICAL OR VETERINARY SCIENCE; METERING BY VOLUME; PHYSICS; SURGERY; TARIFF METERING APPARATUS; TESTING; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR

A sensor (1) used for sensing the flow rate and temperature of gases in a medical airway breathing circuit and designed for insertion into a breathing conduit includes a first thermistor (6) adapted to provide an indication of the gas flow rate and a further thermistor (7) to provide an indication of the gas temperature. The two thermistors are mounted on a projecting portion (5) of the sensor and connected to a cable (2) via a housing (4). The flow sensing thermistor (6) is protected by a portion (3) which carries the temperature sensing thermistor (7). A controller receives information from the thermistors (6, 7) and is able to determine therefrom an absence of gases flow or whether the sensor (1) has been removed from the gases flow, in addition to routine temperature monitoring. A safety feature of the sensor is the occasional operation of the flow rate sensing the thermistor (6) as a temperature sensing thermistor to check its integrity by comparing the temperature values sensed by the two thermistors (6, 7).