CEU Review Form Beyond the Basics: INTERPRETING Altered Mental Status ASSESSMENT Findings (PDF) Valid until October 6, 2008

     EMS providers frequently encounter patients who are not alert and present with an altered mental status, meaning their level of brain function is in question. Various physical examination techniques are employed during the assessment to determine the level of cerebral function and integrity of the brainstem. It is important to understand the limitations of these techniques, as well as potential findings that may cause you to erroneously interpret, report and document the level of brain function. This information is often used to identify trends to determine if the patient's condition is deteriorating, remaining the same or improving.

ANATOMY OF A CONSCIOUS STATE
     Two structures are responsible for a conscious state: the ascending reticular activating system (ARAS) and the cerebral hemispheres. The ascending reticular activating system is not truly a single tangible anatomic structure; however, it is a network of nerve cells and fibers that extend from the spinal cord through the lower brainstem and continue upward toward the mesencephalon and thalamus. The impulses are then distributed throughout the cerebral cortex. The ARAS continuously receives sensory input that allows the body to remain in a wake or sleep state, remain aware of surroundings and respond appropriately while awake. The ARAS has an effect on both the autonomic nervous and motor systems, which in turn control the body's cardiovascular, respiratory and motor response to external stimuli.

     Consciousness requires the patient to have an intact ARAS and at least one cerebral hemisphere. If either the ARAS or both cerebral hemispheres are affected by a particular condition and not functioning properly, the patient will not remain in a wake or alert state. Head injuries, severe cerebral hypoxia or anoxia, central nervous system-depressant drugs and electrolyte disturbances are only a few of the possible factors that would disrupt the function of the ARAS or both cerebral hemispheres and render the patient unconscious.