CPAP humidifier: What It Is, History & Benefits

What exactly does a CPAP humidifier do and how can you get the most out of it? It’s always helpful to revisit basic sleep apnea treatment questions like these to make sure we have the best information about our own treatment, and to make note of tips and tricks we haven’t tried yet.

What a CPAP humidifier does

A CPAP humidifier helps you avoid dry mouth (which nearly 40% of CPAP patients experience)¹ along with dry nose, running nose, chapped lips, sinus-type headaches and nose bleeds – all by doing a simple job that our noses usually perform on their own.

When we breathe naturally, our noses act as humidifiers, warming up the inhaled air to our bodies’ own temperature so that it’s more comfortable to breathe, won’t damage the delicate tissues of our upper airway and lungs, and won’t wake us up, as cold air might. Air coming through a CPAP machine needs its own humidification because it’s entering our upper airway faster than our noses can warm it. This is especially true for those who live in colder or drier climates and/or require high pressures.

CPAP humidifiers: A brief history

The first CPAP machine was invented in 1980. In the late 80s, sleep specialists began humidifying CPAP air by sending it through a chamber of room-temperature water wherein it would pick up what little moisture evaporated as it entered the patient’s tubing. This method was called passive or passover humidification, and was not very effective.

The logical next step was to heat the water itself to create more vapor for the air to absorb. And so heated humidification began in the mid-1990s.

In 2001, Chest published a study that showed humidification “significantly improves” patients’ compliance with CPAP, “and that its need may be predicted” if patients are over 60, taking oral medications that list dry mouth as a side effect, or had prior surgery to remove tissue from their throat.² Of course, we now know that humidification can make sleep apnea treatment more comfortable, especially for patients on higher pressures, which is why…

More CPAPs like ResMed’s AirSense™ 10 and AirCurve™ 10 machines come with an attached CPAP humidifier. You can remove it if you want and insert a cap on that end of your machine.

Two side effects and how to avoid them

Humidification has two main side effects: One is that you may still experience dryness-related symptoms if your CPAP humidifier’s temperature or humidity level is set too low.

The second, more common side effect is called rainout. It occurs when heated air cools in your tubing and reaches your mask as water, causing you to get a damp face. Rainout can be avoided by using a heated tube and adjusting the temperature of the tubing and/or the level of humidification that your water chamber is producing. Your home medical equipment (HME) provider or sleep specialist can show you how to make adjustments on your specific machine.