This CE activity is approved by EMS Magazine, an organization accredited by the Continuing Education Coordinating Board for Emergency Medical Services (CECBEMS), for 1.5 CEUs.

• Discuss the pathophysiology of syncope
• Review prehospital assessment and management of the syncope patient

     Whether in the hospital or prehospital environment, syncope is one of the more perplexing diagnostic challenges facing clinicians. An understanding of the pathophysiology behind syncope, common causes and diagnostically significant examination items can lead to appropriate field decisions and treatment.

     You are called to a 67-year-old man who has fallen from a small stepladder. His coworker tells you that he seemed unresponsive after the fall for "a few minutes." Upon your arrival, the patient is alert and oriented, and is refusing care. He doesn't believe he slipped or tripped. "I think I just passed out for a minute," he says. "It happens."

     The above is a classic presentation of syncope, which is defined as a transient, self-correcting loss of responsiveness and postural tone. In the simplest terms, the patient passes out, falls down and quickly returns to normal. Depending on the patient's position when syncope occurs, injury may occur. If the patient is still unresponsive upon your arrival or has a lingering altered mental status, he has not experienced syncope.

     Syncope is not a disease in itself, but rather a term for the physical presentation that occurs when the brain, which is particularly sensitive to deprivation of oxygen and glucose, is deprived of circulation.

     The brain, which at any given time consumes about 20% of the body's oxygen, does not tolerate anaerobic metabolism as well as other parts of the body. Without oxygen and glucose, brain function rapidly ceases. A loss of approximately 35% of cerebral blood flow will result in unresponsiveness. Both the cerebrum and the reticular activating system have roles in consciousness and posture; hypoperfusion to both areas results in syncope.

     There are many potential causes of syncope. This section breaks down the more common causes into pathophysiology-based sections.

     Vascular and blood-related causes: Low volume may result from a wide range of conditions including gastrointestinal bleeding, vomiting or diarrhea. Diminished oral intake and excessive heat with perspiration can worsen the condition. A history or indication of anemia, cancer, sepsis or other shock condition may also cause a syncopal episode. The vascular system is usually involved to some degree in all cases of syncope.