Medical Dictionary defines implied consent as "the granting of permission for health care without a formal agreement between patient and health care provider." When a person makes an appointment with a doctor, for example, consent is implied for that patient to receive care.
The University of Washington School of Medicine notes that consent is typically presumed in the case of an emergency when a patient is unconscious or incompetent and no other means of coming to a decision regarding treatment is available. If the intervention of a physician is necessary to prevent further injury, disability or death, the principle of beneficence obligates him to act on behalf of the patient.