The Pennsylvania Supreme Court recently ruled that the police need a search warrant before they can take blood from an unconscious driver.
The facts are briefly summarized as follows. The police saw a driver and it appeared that he was so drunk he needed medical attention. They took the driver to a hospital where he was given a drug which rendered him unconscious. While unconscious the police officer who accompanied the driver to the hospital read a statement to the unconscious driver advising the driver of civil and criminal penalties such as losing his license if he refused to allow the hospital to take his blood. Even though the driver did not respond due to his being unconscious, the police officer went ahead and ordered the nurse to take the driver's blood.
Although one Justice dissented saying that when the driver got his license he gave implied consent to the taking of his blood, the majority of the Court disagreed and held that a search warrant would be required.