Read "First, Try to Do No Harm" in The Wall Street Journal:
Mr. Owen says the surgery scenes were particularly taxing. In the operating theater, he had to speak with nurses and fellow doctors, explain the surgery to spectators—and at the same time make sure his surgical handiwork looked convincing. "I'm playing this genius doctor, so you don't want the [camera] cutaway to somebody else's hands being brilliant," Mr. Owen says. A historical consultant, Dr. Stanley Burns, supplied period photographs of operations and advised on the surgery scenes. Mr. Owen says, "Often his mantra was 'more clamps and more blood.' "