"MAMPU." I came across these letters several years ago while working at a hospital. They seemed common enough because they were repeated in the physical therapy daily notes under different days. I had never seen them before and asked for an interpretation. "Multiple attempts made, patient unavailable."
There was no other description or explanation of why the patient was not seen. Other places I have worked would write the reason why the patient was unavailable, i.e., patient at X-ray, surgery, transferred to ICU etc. A line or two of narrative explanation about why a person was not treated can be helpful to the person who follows in a therapy session.
When I went to work at a new hospital, I had carried over some bad habits of writing in code. One of them was "UIC" meaning "up in chair." The PT who treated the person the next day asked me about it and thought the U was a V and wondered why I was using a certain vapor rub on the patients after treatments. It took several years to break some of the bad code habits I picked up right out of school.
I still have the booklet of acronyms from my very first job as a PTA. The 100 pages covered each department of the hospital, using every conceivable letter combination. I thought I had struck gold until I realized each new employer has its own set of approved acronyms. I will occasionally fall into using some of them but with computer documentation the norm, I find it easier to write the whole words out instead of using our medical shorthand.
The other problem I have is mixing in texting shorthand when typing patient notes. I have done this once or twice and have to go back and edit my notes because I have inserted a number instead of a word. "Mayb we can mrg tha 2 somday n it wil b aceptbl."