Advice to help curb chewing of oxygen nasal cannula?

Have you tried securing the nasal cannula tubing to her cheeks/skin? There are several options including latex free grips that are made of porous tape that allows the skin to breathe.

We don't know how many liters a minute she's (supposed to be) getting with the nasal canula.

We don't know what her oxygen saturation is with and without oxygen.

We don't know if her doctor is OK with the O2 being off.

We don't know if she gets cyanotic (lips turn bluish color) without oxygen?
Many unknowns here.

For a regular mask, as long as it is set at 5 liters or above, you don't have to worry about rebreathing CO2. The force of the incoming oxygen pushes the exhaled breath out through the flaps on the sides of the mask.

For the non-rebreather mask, I've had hospice patients use a Y connection with 2 tanks to deliver a higher flow. The n-r mask needs 10-15L/min.

Dorothy says her anxious figiting is caused by the dementia.

If the oxygen suggestions don't work, see if she can be prescribed a mild anti anxiety med by her doctor or neurologist.

Over and out.

Why  does she have anxiety? Address that first.

Hey Mac,
No reason to be sorry. I failed to state what kind of mask was needed. My bad. It's called a non-rebreather mask.
From Wikipedia;
"The non-rebreather mask covers both the nose and mouth of the patient and attaches with the use of an elastic cord around the patient's head. The NRB has an attached reservoir bag, typically 1 liter, that connects to an external oxygen tank or Bulk Oxygen Supply system. Before an NRB is placed on the patient, the reservoir bag is inflated to greater than two-thirds full of oxygen, at a rate of 15 liters per minute (lpm). Approximately ¹⁄₃ of the air from the reservoir is depleted as the patient inhales, and it is then replaced by the flow from the O2 supply......

.....Exhaled air is directed through a one-way valve in the mask, ""which prevents the inhalation of room air and the re-inhalation of exhaled air"". The valve, along with a sufficient seal around the patient's nose and mouth, allows for the administration of high concentrations of oxygen, approximately 60% - 80% O2........"
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So, that solves re-breathing already exhaled air causing no carbon dioxide buildup.
As for the strap, they are adjustable and can be loosened to be just snug enough to keep it on her face.
As for irritation from the mask, padding the perimeter of the mask with tear-able cotton (like cotton balls but comes in sheets) can lessen friction.

Of course, humidifing the oxygen is more comfortable and prevents drying out of the mucous membranes.

For those who mentioned does she need it at all since she's "tolerating" it off, you would have to do an oxygen saturation level (easy-$20. Oxymeter (a finger clip) that reads oxygen saturation and pulse can be purchased at any pharmacy without a prescription).

People who have chronic lung disease "compensate" pretty well and it's not unusual for them to have O2 saturations in the mid to high 80's. (Those without lung disease are 96-99%). If she is less than the high 80's, she needs oxygen but it's up to her and the family. Obviously her doctor ordered it for a reason (to prevent hypoxia-(a pathological condition in which the body or a region of the body is deprived of an adequate oxygen supply).

I offered this as an alternative to possibly swallowing or aspirating chewed bits of nasal canula tubing. Just a suggestion.

Please check with your doctor to see if it would be a viable alternative.

If you have been having to replace the cannula daily, then your grandmother has been doing without her oxygen nightly.

Unless she has suffered observable harm as a result, I too would question whether the oxygen is of any real benefit to her.

Would she be more compliant with an oxygen mask? They have an elastic cord that goes around the back of the head. Worth a try.

I would suggest taping the tubing to her cheeks with paper tape, but if she uses her hands to grab it out of her nose, then that won't work.

Can you keep her hands busy with a stuffed animal or other gadget so she'll forget about the O2 tubing?
As a very last resort, they used to have hand covers (like a small palm-sized ping pong paddle covered with soft cloth with netting at the back of the hand secured with velcro). Impossible for the patient to remove.
Not sure where you'd get those. I used them in the hospital 40 years ago for confused patients who wanted to pull out all their tubes. Not sure if they even would be legal anymore.

I'm not one to recommend meds as a first option, but perhaps something might address the fidgeting (and anxiety?) so that she doesn't chew on the cannula.

You could tape something nasty tasting on the cannula, but I'd be concerned that it might not stop her and could end up causing more discomfort.

Have any of her doctors indicated that the fidgeting is b/c of dementia? Is it only at night or during the day as well?

Besides having dementia, Is she afraid of something? Is she taking Ambien or a med that causes nightmares? Does she have food with high sugar content for her evening meal?