I would imagine (but don't know for certain) that Lorazepam might relax your throat. I also believe taking this medication would lower your oxygen levels. I'm not a doctor, but I used to take Lorazepam to fall asleep (because I had huge anxiety about not being able to breathe when I fell asleep). Lorazepam made my O2 levels fall alarmingly during sleep, so this medication didn't help me breathe while I was sleeping. Finally my cardiologist sent me for a sleep test. Now - no more nightly Lorazepam! Just a mask, hose and xPAP therapy.
First, download SleepyHead. Get some nightly stats. Second, ask the doctor that is prescribing Lorazepam to give you an over-night pulse oximeter test. See what your O2 levels are doing at night. And do this FAST. Your life may depend upon it.
Rather than asking the doctor for ONE overnight pulse ox study why night buy you very own CMS 50x wrist pulse ox and an overnight study whenever you are curious and bring the results to your doctor if an when you see him. In the mean time you will know what is happening with your health.
In addition to my APAP ASV machine I have a CMS 50i pulse oximeter and a recording blood pressure machine and my own Iratio 2 INR test machine so I can view track and print out my important info and present it to my doctors if they show an interest. Weather or not the doctors care I can monitor and track my results and make my own adjustments when needed. More often than not I tell my doctor what I want and he simply says OK. He has learned how persistent I can be. He will even go to bat for me when the system doesn't cooperate.