At the time of my first MRI, which was done in a mobile unit with a very long, dark tube, I found out I was claustrophobic and it had to abandoned! Boy I was spooked, it didn’t make sense. So, I had to find a hospital with an ‘open MRI’, even then I had an irrational fear that I couldn’t explain but the hospital let me go to look at the scan and have a mini-try, the day before and that helped. My GP also gave me a mild sedative to take before hand, I think it was Diazepam.
I made sure I kept my eyes shut throughout and they gave me a button to press if I needed attention (so I could talk to them and they could talk to me and fetch me out if I needed to) but I was ok in the end, that sort of reassured me and it was done. Years later I managed to get an upright MRI which was much better for those with claustrophobia, or for children, it wasn’t as ‘clanky’ and they even put a DVD on a big screen opposite, for you to watch during the process.
As for the POTS, I didn’t have the drop in blood pressure type but I’m certain I had the lack of blood volume and I did learn that even drinking vast amounts on it’s own is no good. You have to take extra salt in order to retain the fluid. Drinking vast amounts can also be detrimental because you pass away various essential elements in the process.
Another thing that I found helped with my POTS was, making sure my head was never held in the ‘flexion’ position, always lift whatever you are doing, so that your head can be as straight forwards as possible.