thelivefeed's James Hibberd reports that NBC has stated that Trauma will air for at least the next 3 weeks.
Although in the same post Hibberd makes the guess that "The decision on "Trauma" might [go] down to the wire." which is nonsense. The show is 100% dead, whether it goes its entire 13 episode order is the only thing left to wonder.
Update: Nick C has an interesting theory that NBC is hanging onto its dreck through the Olympics since they want to debut new shows after the Olympics promo opportunity. Makes sense.