It is simple why you havent seen many DOs in CC.
the ratio of MD to DO is huge (DOs are newer to the game)
The ratio of docs to specifically CC docs is huge (the CC field is very short staffed currently)
Now if you look at the % of CC docs, which is not alot, many small-medium sized hospitals have none, the hospitalists, surgeons and PCPs just take care of their pts in the unit because of the shortage, and then factor in the % difference in MD and DO, you will not meet alot of DO intensivists. But that goes the same for DO neurosurgeons, DO ENT's etc etc.
As the field grows, the number of programs grows, and the ACGME and AOA merge, you will see more.
Lastly, DO schools preach primary care. It is in the fundamentals of their teachings from day one of medical school (and it droe me crazy as I detest primary care) So the % of us that finished DO school and went on to become Intensivists, anesthesiologists, surgeons, etc, is a not a large % although it is changing.
Bottom line, DOs are docs and can do every residency and fellowship. How many you encounter in a particular field will vary alot on the area. in the NE where there are many DO schools (Penn, NY) there are lots of DOs in all fields. In the midwest it is similar. on the west coast and in the SE, excepting FL, there are fewer, because the schools there are fewer and newer and this the programs are fewer and newer. I worked with 4-5 DO intensivists in medical school in upstate NY. they are around
