I do Emergency Psychiatry almost exclusively.
I work 12-hr shifts at a county psychiatric hospital in the emergency section. There are 2 psychiatrists per shift. We have complete responsibility for the health/welfare of the 8-15 pts on the unit at any given time. Sometimes, our unit census rises as high as 30, and highest I know was 42 (a very bad day).
We are a free-standing psych hospital with no medical backup of any type on site. Our "crash cart" has O2, mask, BVM, suction, AED, and NO meds. I can get ASA, NitroStat, Ativan (PO or IM) from the regular meds nurse, but that takes 3-10 min. In any sort of medical emergency, we call 911.
Each shift, I re-evaluate 2-4 pts from the last shift, whose clinical picture was expected to change enough to maybe not need admission (usually drug/alcohol intoxication, or chronic condition but might do well enough after 1-2 doses of meds to maybe be able to go home).
I evaluate 8-12 new pt's per shift (~50% known to the system), about 70% are involuntary and often quite angry about that, easily 80% have co-morbid substance use issues, but only ~20% are clinically intoxicated.
From 430pm - 830am, the emergency psychiatrists are also responsible for all the psychiatric inpatients in our hospital, 12 adolescents, 48 "regular" adults, 12 "psychiatric ICU" adult patients.
This all seems to be relatively "normal" for a Psychiatric Emergency setting in an urban/suburban setting > 500k pop'n.