Gina, it does not make sense to me that they check his Oxygen levels at the same time he is on supplementary oxygen. That doesn't tell them whether, or when he needs it .
The carbon dioxide levels have to be checked by taking blood from an artery in the wrist.
Do you have access to an ALS clinic or a doctor who is very familiar with ALS?
Here's what I would do on Monday (unless you have an emergency) when everything is open again :
1. Call the medical person who has most knowledge about ALS and tell them that you want your husband's carbon dioxide levels checked. Don't give up until they have done it.
If you have access to a specialist in ALS and lung function, that's the person to contact.
2. If they check his oxygen levels again make sure they do it at a time when he has been off the oxygen for as long as possible. If they are normal at that time, ask some questions as to why he is on the oxygen and when he needs it. Activity (even talking) will change the levels of oxygen so a reading at one time may not be the same as a reading at another.
With ALS the lungs themselves are normally healthy, it's the mechanism for drawing air into/letting it out of the lungs -- the muscles including the diaphragm -- that's at fault. The most frequent result of this is increased levels of carbon dioxide that make people sleepy, fatigued, and less alert.
If the lung tissue is healthy it is my understanding that most PALS can usually make good use of the oxygen that is present in the normal air if they are using a Bipap to pull that air in.
My husband's Bipap levels were prescribed by the pulmonologist and cannot be changed by the Respiratory tech. without another prescription or discussion with the doctor. Do you know who prescribed the levels on your husband's Bipap?
The use of oxygen can increase carbon dioxide levels in the body so I'd really push getting carbon dioxide levels done.
I am certain you are doing an excellent job caregiving--and yes, it is overwhelming. Be comfortable with what your husband chooses to do about taking the Ativan.
I hope your weekend is a calm one.