Nasal Cannulas and Oxygen Masks: Choosing and Caring for Them

The main types

Nasal cannula. A soft tube with two short prongs that sit just inside the nostrils, held by tubing looped over the ears and tightened under the chin. It is the most common device for home oxygen. It allows eating, talking and coughing while oxygen continues. It is usually suitable for flows up to about 4 litres per minute; above that, it dries the nose and the extra flow brings little benefit, though your doctor decides. It works only if the person can breathe through the nose at least in part.

Simple face mask. A soft plastic mask covering the nose and mouth, with side holes for exhaled air. It can deliver higher oxygen concentrations than a cannula and is used for short-term needs, for people who breathe through the mouth or when a higher flow is needed. It usually requires a minimum flow, commonly about 5 litres per minute, to prevent the person from re-breathing their own exhaled air. It is not suitable for long-term use at low flows. The doctor sets the flow.

Venturi (controlled) mask. A mask with a colour-coded valve that gives a fixed oxygen percentage, used when precise control is needed, especially in people at risk of carbon dioxide retention. Mostly used in hospital, sometimes at home on specialist advice.

Mask with reservoir bag. A mask with a bag that fills with oxygen, giving high concentrations. This is for emergency or hospital use, not routine home care.

Nasal high-flow devices and CPAP masks. Specialist devices used on medical advice, with their own training.

Tracheostomy oxygen devices. For people with a tracheostomy; these need specific equipment and training; see all you need to know about types of tracheostomy tubes.

For most older adults at home on long-term oxygen, a nasal cannula is the starting point.

Choosing and sizing

• Ask the doctor or supplier which type suits your parent's prescription and breathing pattern.
• Size: cannulas come in adult sizes, and masks in small, medium and large. The prongs should sit comfortably in the nostrils without pressing, and the mask should cover the nose and mouth without squashing.
• Softness: soft, flexible prongs and tubing are kinder to sensitive nostrils.
• Tubing: a lightweight tube reduces pull on the ears. Some tubing has a smaller diameter and kinks less. Avoid very thin, stiff or old tubes.
• Length: long enough to move around, and no longer than the maker's maximum. Excess tubing is a trip hazard. See falls risk assessment at home.
• Compatibility: make sure the connector fits your concentrator or cylinder. Do not force or tape mismatched fittings.
• Spare sets: keep at least one spare cannula or mask at home and one in the travel bag.
• Allergy: some people react to certain plastics or adhesives; report rashes.

How to fit a cannula

1. Wash hands. 2. Check the cannula and tubing for cracks, kinks, dirt or a damaged tip. 3. Turn on the oxygen at the prescribed flow and check there is gas at the prongs by feeling for a gentle flow on your hand. 4. Place the prongs in the nostrils with the curve following the shape of the nose, pointing backwards and downwards, not upwards. 5. Loop the tubing over each ear and then down under the chin. 6. Slide the adjuster under the chin until the cannula is snug but not tight. Use the adjuster to take pressure off the ears. 7. Check comfort: no pulling on the ears, no pressure on the nostrils, and the tubing lies free of the neck. 8. Secure the tubing along clothes with a clip so it does not tug.

Breathing through the nose gives the best benefit with a cannula. A mouth breather still gets some oxygen because air mixes in the back of the nose, but the benefit may be less, and the doctor should know.

How to fit a mask

1. Wash hands and check the mask and tube. 2. Turn on oxygen at the prescribed flow before putting the mask on. 3. Place the mask over the nose and mouth, starting at the bridge of the nose. 4. Pull the elastic strap over the head and adjust so the mask fits snugly without being tight. Squeeze the metal nose clip to shape it. 5. Check for leaks around the eyes and chin. 6. Make sure the person can breathe, talk and cough and that the mask can be removed quickly if they vomit.

Masks can feel claustrophobic and make eating, drinking and speaking hard. Take the mask off only on the doctor's advice or for short periods under supervision, switching to a cannula if prescribed. Never leave a confused or very drowsy person alone in a mask.

Never change flow or device on your own

Different devices need different flows. A cannula at 2 litres per minute, a mask at 5 and a controlled mask at a set percentage are not interchangeable. Swapping a cannula for a mask without advice, or using a mask at a low flow, can cause re-breathing of exhaled gas. Follow the prescription; see oxygen flow rates and prescriptions: what families should know.

Skin and comfort care

Oxygen devices press on the nose, cheeks, ears and neck for many hours, so skin damage is common.

• Check the skin daily around the nostrils, behind the ears, on the cheeks and under the chin for redness, soreness, blisters or ulcers.
• Pad pressure points with soft foam or gauze tube covers, which are available for ears and cheeks.
• Reposition the tubing and rotate the way it sits each day to relieve pressure.
• Dry nose and lips: a humidifier bottle or a water-based lubricant may help, as advised by the doctor or pharmacist. Do not use petroleum jelly, oil, balm or greasy creams; they are a fire hazard with oxygen and can damage the device.
• Nosebleeds or a very dry, sore nose need medical advice.
• Fragile or bedbound people are at higher risk of pressure damage; see pressure ulcers: stages, wound care and prevention.
• Keep skin clean and dry and wipe away moisture under the mask.

Cleaning and replacing

Clean devices reduce chest infections.

• Wash hands before handling.
• Wipe the cannula prongs and the mask daily with a damp cloth and mild soap, or the cleaner recommended by the supplier. Rinse and dry. Do not soak electronics.
• Wash masks in warm, soapy water weekly, rinse well and air-dry, following the maker's instructions. Avoid harsh disinfectants unless advised.
• Do not boil unless the maker says so.
• Replace the cannula about every two to four weeks, or as the maker or supplier advises, or sooner if dirty, stiff, cracked, after a cold, flu or chest infection, or if it smells.
• Replace the tubing every one to three months or as advised; replace it if it has kinks, discolouration or moisture build-up.
• Humidifier bottles: empty, wash and refill daily with the recommended water, as in using an oxygen concentrator safely at home.
• Never share a cannula or mask.
• Keep spare, clean sets in a clean bag, not on the floor.

See a cleaning schedule for breathing equipment.

Common problems and fixes

• Sore ears: use padding, adjust the slider and check the tubing.
• Dry nose: discuss humidification; avoid oils.
• Nose bleeds: report to the doctor.
• Tube keeps kinking: check the route; use a swivel connector if the supplier offers one, and keep the tube straight.
• Water in the tube: from humidification or condensation; disconnect and drain according to the manual, and tell the supplier if recurring.
• Hissing at the connection: a loose joint; reconnect.
• Mask fogging or feeling stuffy: check flow and fit; do not raise flow yourself.
• Person pulls the device off: common in dementia or delirium. Do not restrain; tell the doctor, and see dementia and medicines: managing safely for general principles on behaviour. A change in behaviour may signal low oxygen or infection.
• Eating with a mask: ask the doctor whether a cannula can be used for meals.
• Skin allergy: report and ask for an alternative material.

Fire safety

All oxygen devices carry fire risk. No smoking, no flames such as diyas, candles, stoves or incense near the person or tubing, no oil or grease on the face or connections, and keep heat sources away. Brief everyone at home. See safe use of oxygen and electrical equipment and smoke and gas safety for older adults.

When to ask a professional

Ask the doctor or supplier to confirm which device and flow are right for your parent, how many hours to use it and whether a mask is ever needed. Ask a nurse to show proper fitting and skin care. Call the doctor for increasing breathlessness, drowsiness, morning headaches, repeated nosebleeds, skin ulcers or if your parent will not tolerate the device. Check readings with an oximeter if advised; see pulse oximeters: how they work and how to use one. Call 112 for severe breathlessness, blue lips, confusion, chest pain or collapse.