In general, patients who present to the Emergency Department with an altered mental status are deemed legally incompetent to make medical decisions regarding their care. The alcohol impaired individual who refuses treatment is often not capable of understanding the risks, benefits, and alternatives of treatment; therefore, an informed decision can not be made. The legal limit for driving in terms of blood alcohol has very little to do with the capacity to make informed decisions. Intoxication is not used to indicate a level that increase the risk of injury while driving, but rather, a term used to describe a level which produces clinically identifiable impairment which may alter sensation, coordination, judgment and insight. If blood alcohol levels are obtained and they are well in excess of the legal limit to drive, you must assume that capacity has been lost. Both judge and jury continue to put stock in the 'legal limits'.

Some states have specifically legislated that there shall be no legal recourse against physicians for examining and treating a patient without his or her consent if the patient is intoxicated or under the influence of drugs, or otherwise incapable of providing informed consent. In Mississippi, the law defines who may consent to medical treatment. It excludes those of unsound mind, related to “natural state, age, shock, anxiety, illness, injury, drugs or sedation, intoxication, or other causes of whatever nature.”

In states without such statutes, case law supports the underlying philosophy that intoxicated patients are incapable of giving consent. In Miller v. Rhode Island Hospital, the Rhode Island Supreme Court held that a patient’s intoxication may render him incapable of giving informed consent, and in emergency situations, that consent may be waived. In this case the plaintiff, Miller, had a blood alcohol level of .233 and was involved in a MVA. The attending surgeon decided that with the nature of the accident and the patients intoxication a diagnostic peritoneal lavage was indicated, which he performed over the patient’s objection. In Blackman v. Rifkin, the Colorado court found that intoxication coupled with head trauma permits emergency physicians to restrain a patient and imply consent necessary to treat his condition.

In the pre-hospital setting some states have provide legislative protection from liability for emergency medical personnel and police in restraining intoxicated patients who are under the influence of drugs or alcohol. In Illinois, the Alcoholism and Other Drug Abuse Dependency Act provides that a person who appears unconscious or in immediate need of medical services while in a public place and shows symptoms of impairment brought on by alcoholism or other drug abuse may be taken into protective custody and brought to emergency medical service.