Yakin Byoutou San
English name: Night Shift Nurses: Experiment
Genres: Hentai
Type: OVA, Episodes: 3
Aired: Jul 29, 2005 to Jan 27, 2006
Studio: AT-2
Source: Visual novel
Rating: Rx - Hentai
Synopsis:
Sora was lying in front of a hospital. He was seriously injured, and when he was about to die, a nurse, Yamami Yu, helped him. 
He was sent into an emergency ward, and he met a beautiful woman, Mikage Reika. She was a director of the hospital, and she asked him to become a test subject. Because he didn't have any relatives, he accepted it. Then, Yagami Yu was supposed to take care of him. 
Since that day, his fate had changed a lot.

(Source: AnimeNfo)