Most states do allow for blood to be taken under these circumstances.  While it may not seem fair to you most courts have found that this is neither a violation against an individual's right against self-incrimination or a violation of their right to due process.Specifically, North Carolina has an "implied consent" law.  This means that you agree to submit to a chemical test of your blood, breath or urine if an officer of the laws suspects that you are driving while intoxicated. If you refuse such a test your drivers license will be immediately suspended for 30 days followed by a hearing in which the court could suspend your drivers license for an additional 12 months.I realize that if the individual were conscious he still could have refused (although there would have been fines and penalties),  yet while unconscious he was not able to so refuse.While tt does appear that the officer was well within his right to take a blood sample such as this you may just want to check  further since I'm not a praticing attorney in North Carolina.  Try calling the DMV or possibly the Public Defender's office just to make sure.