We're working on our end on your quest.
May I suggest you visit the Chimborazo Visitor Center at Chimborazo Park in Richmond.
I believe the National Archives may not be too fruitful.
If you've never been there before, you will want to enter through the "backdoor." That is from the Pennsyvannia Ave. side. I haven't been there for 7 years. However, the main microfilm viewing place used to be on the 4th floor. The reading room for items requested, on the 2nd.
However, if you really want to get serious, you need to visit the Old Army Archivists located well within the bowels of the building.
In Record Group 109 are many hospital records. Going through these are quite a choir.
Best you do your homework in advance, contact these folks which will hopefully streamline your time.
I'd love to hear the results of your efforts.