HVAC is not my field, just a bit of an interest, I am an electronics engineer that once worked in a hospital.
You are going to have normal building loads, plus occupancy (obviously) that may be up to a dozen people in a very long complex operation, such as brain or heart surgery. There can be several surgical teams that work in rotation, sometimes two teams may be present.
Then there will be the total electrical input, which includes high intensity lighting, patient monitoring equipment, life support equipment, that could easily add up to several Kw I would expect.
The number of air changes will need to be fairly high, manly because electro surgery creates rather foul smelling smoke from burning flesh, plus the use of flammable medical and anesthetic gasses and volatile liquids.
The whole operating room problem is rather different, including a much higher than usual level of air filtration. Obviously dust and pollen can be sources of infection, airflow direction is always downward to settle dust.
I cannot give figures, only point out some of the basic requirements to someone not at all familiar with hospital operating room procedure. You probably really need some very expert advice.