You will likely receive a summons to be arraigned. However, you may be arrested depending on the seriousness of the event. I suggest you retain counsel asap to go over things with you and to obtain more info. If there was a blood test done, the police or prosecution may obtain it. You can always fight it.
The above is NOT legal advice, and is NOT intended to be legal advice. No Attorney-Client relationship is created through the above answer.
Generally, if you require inmmediate medical attention, ie. ambulance ride, the police will forgo an arrest and summons you into court. Once the police formally arrest someone they have to guard the person at the hospital, which they don't want to be tied up with, so they will generally summons. The exception is when there's a fatality or other high profile reason where the party may be a flight risk. An arrest is a procedure for identifying someone (photograghing, printing, entering data into the system) that may ignore a summons or may not be otherwise reached for arraingnment. That being said, one generally wouldn't be arrested who needs medical attention unless that person couldn't be issued a summons instead.