Let’s be clear. Nightingale was British and is best known for nursing in the Crimean War. She had interests in many other situations but I found no indication that she ever came to the United States.
Her importance to the American Civil War was her 1858 report on the Crimean War: Notes on Matters Affecting the Health, Efficiency, and Hospital Administration of the British Army. In this 853-page report, she analyzed evidence and drew the conclusion that 16,000 of the 18,000 deaths were due to unhygienic hospital conditions.
Certainly, that would have affected Civil War hospital treatment, wouldn’t it?
No, the Royal Commission’s official report was much shorter—and omitted most of the damning evidence against supervising medical doctors. It’s this report, if any, that Civil War doctors would have read. After all, Nightingale was “only” a nurse.
So, doctors in the Civil War didn’t change a thing. And 2/3 of the soldiers’ deaths could have been prevented.