humidifier
Meaning of humidifier: Adding water to air only helps within a range, since too little dries the airway and too much feeds mold and dust mites.
Definition of humidifier
A humidifier is a device that adds water vapor to air, either into a whole room or directly into the gas delivered by breathing equipment. Moister air eases the dryness, irritation and crusting that affect the nose, throat and airways, particularly where indoor heating has stripped water out of the air. Models differ mainly in whether they heat the water before releasing it.
What types are there?
| Type | How it works | Points to note |
|---|---|---|
| Evaporative cool mist | A fan draws air through a wet wick or filter | Self limiting, because air stops taking up water once it is saturated |
| Ultrasonic cool mist | A plate vibrating at high frequency throws off a fine mist | Quiet, but minerals in hard water are scattered into the room as fine white dust |
| Warm mist or steam | Water is boiled and the vapor released | Boiling kills organisms in the tank, though the unit itself is hot |
A humidifier is not a nebulizer. A nebulizer turns a liquid medicine into a mist fine enough to be inhaled into the lungs and delivers a measured dose; a humidifier moistens air and carries no drug at all. The two are sometimes confused because both produce visible vapor from a small medical device.
How are they used with medical equipment?
The nose normally warms and moistens every breath, so equipment that bypasses or overwhelms it takes over that job. Ventilators and machines used for sleep apnea run heated humidifiers to stop the airway drying out over a whole night or longer. A person breathing through a tracheostomy has lost the nose entirely, and a compact filter placed at the opening captures moisture from each breath out and returns it on the next breath in. With ordinary low flow oxygen through a nasal cannula, added humidity makes little measurable difference and is often left off, while high flow systems always require it.
What goes wrong with them?
Standing water is the recurring problem. A tank left filled between uses grows bacteria and mold, which the machine then disperses into the room as an aerosol, and outbreaks of lung infection have been traced to contaminated water in humidifying equipment. Steam models cause scalds, especially where a child can reach one. Running a humidifier hard for long periods pushes indoor humidity high enough to encourage dust mites, mold on cold walls and condensation on windows, so more moisture is not automatically better.
Used in a sentence
A humidifier was attached to the oxygen equipment to reduce dryness of the patient's nasal passages.
Good to know
A humidifier attached to supplemental oxygen equipment addresses dryness caused by the gas delivery itself rather than treating the underlying condition requiring oxygen.