Dr. Kelso, as chief of medicine would serve primarily in an administrative role. His day to day interactions with the staff, including daily rounds would be extremely unlikely.
The chest x-ray in the credits is backwards (the heart is to the right). There is a very slight possibility of "dextrocardia" or "situs inversus" (when the heart is turned in the wrong direction), but this is rare enough that it is simply an error.
The x-ray with the show's title shown in the beginning is turned the wrong way: the heart should be seen on the right hand side. This was an intentional mistake put in by creator Bill Lawrence to represent the core idea of the show: young doctors in over their heads. Bill Lawrence reminds viewers that this goof was completely intentional in interviews, DVD commentaries, and virtually any other available opportunity.