Temperature alarm and cut-out system for use with heated water humidifiers

The temperature of the inspired humidified gases of an intubated patient may be monitored accurately, close to the airway, by a commercially available thermistor probe and alarm/cut-out device for use with heated water humidifiers. The apparatus is designed to alarm when the inspired gas temperature exceeds the pre-set temperature and when the thermistor probe is in open or short circuit. When the temperature alarm is activated, the humidifier heater is switched off automatically, thus preventing prolonged transmission of excessively hot gases to the airway. The apparatus has been used successfully in this hospital for several months, requiring minimal observer attention and maintenance.