Captain McCreany was the fire department captain in the Season 6 episode Help Me. He was portrayed by actor Jamie McShane.
After House finds Hanna trapped beneath the rubble, he and McCreany keep arguing about the best course of conduct. House wants to make every effort to free Hanna and save her leg, while McCreany wants to proceed with an immediate amputation so they can treat Hanna in hospital and get her away from the risk of further collapse.
At the beginning, House wins and McCreany agrees to provide help to lift the heavier structural elements off of Hanna's leg so she can be freed. However, after the first attempt, the rubble shifts making further efforts perilous.
House wants to continue to try even though it's likely Hanna will develop crush syndrome the longer she's trapped, and finally Cuddy has to intervene to convince House that amputation is the best course.