Good luck with this one. After spending a couple of years working on something like this, I found the following:

  1) A majority of doctors are in small private practices
     that reinvent the wheel of how they run their practice.

  2) All of these doctors are extremely pressed for time
     and are practically _always_ behind schedule.

#1 means you need to build heavily-configurable software, and #2 means the doctors don't have the time or energy to learn and configure your software. At best you can get the practice managers to force it down the doctor's throats, which doesn't exactly help either.

Record keeping is to doctors like text editors is to us hackers. Imagine if a doctor had built your text editor; They're probably very smart and energetic, but they don't really understand your problem and how much you personally need specific things just so.