The protocol for Syncope:



Let’s break it down!

Syncope is not a definitive diagnosis; rather it describes the consequence of some preceding cause. Anything that causes up to 10 seconds of interrupted blood flow to both cerebral cortices or the brainstem reticular activating system will result in loss of consciousness, or what we might call a “syncopal episode”.

Statistically speaking, everybody has a 10.5%-19% chance of experiencing syncope at some point in their life. In 25% of these people, it’s consistently recurrent. Luckily for us, the causes of syncope are almost always benign, especially in the young and healthy military population. Here’s a quick rundown of the stats of syncope-causing culprits:

  • Vasovagal stimulus (21%): The vagus nerve extends from the neck down to the abdomen and it controls your parasympathetic responses (“Rest and Digest” system). When it becomes reflexively stimulated (via emotional stress, the sight of blood, pain, prolonged standing, etc.) it causes a sudden drop in heart rate and blood pressure, thus resulting in syncope. Typically very benign; patients tend to recover quickly after being supine.


  • Cardiac (10%): Cardiac syncope refers to many heart-related causes such as arrhythmias, ischemia, structural/valvular abnormalities, tamponade, etc.  Not as common in younger patients, but still worth noting.


  • Orthostatic Hypotension (9%): Also known as “Postural Hypotension”; occurs when there is a sudden drop in blood pressure (>20mmGH) after a person assumes an upright position and gravity causes a shift in blood to the lower body. Usually, the body can compensate enough to avoid a loss of consciousness, but things like dehydration or new medications can limit the vascular response. 


  • Medication-Related (7%): medications that affect the heart or overall blood pressure like calcium channel blockers, beta-blockers, nitrates, and antiarrhythmics can all cause sudden syncopal episodes. 


  • Neurologic (4%): There is no true “neurologic” cause of syncope (that would contradict the definition of syncope, which is a loss of consciousness without neurological etiology). However, there are several neurological causes that can mimic a syncopal episode such as strokes, seizures, or migraines


  • Unknown (37%): Who knows! Syncope occurs so regularly that the exact mechanism isn’t always identified.

For a good summary of the topic, check out the video below:

Chances are, you’ve probably seen somebody pass out before. You may see them get pale and lose focus just before collapsing, but usually, syncopal episodes happen so quickly that they’re hard to intervene with. A return to normal mentation typically follows soon after reperfusion in the supine position

Just after collapsing, the patient may or may not experience secondary “convulsive activity” due to a lack of perfusion to the brain, but this is not to be confused with true seizure activity.  You can often tell the difference by observing for signs of urinary incontinence or tongue biting, which is frequent in true seizures. In addition, these patients will also have to be assessed for physical injuries, which can be rather significant especially if the patient’s head strikes a sharp surface.

Below is a compilation video of people having syncopal episodes… just in case you forgot how fast it happens!

Syncope is almost always self-correcting. When the patient loses consciousness, they will typically fall into a supine position where blood flow can be easily restored, as it doesn’t need to work against gravity. If the patient is not laying supine already, then it’s best to put them in that position and maintain their airway.  Airway adjuncts are not typically needed due to the limited time frame of symptoms.  Since convulsive activity may or may not occur, be sure to protect the patient’s head to avoid additional injury to the patient. 

Unconsciousness and Levels of Consciousness

Once the patient has regained consciousness or is at least in a safe position, it’s time for us to play detective and see if there’s anything that’s immediately fixable. Start with the basics:

2. Check blood glucose; correct hypoglycemia prn

A normal blood sugar level for an adult can range anywhere between 72-140 mg/dL, depending on when their last meal was. Those who drop below 70mg/dL may be at risk for loss of consciousness.  However, this rarely occurs unless the patient is a known diabetic.  Nonetheless, if you check a finger stick glucose in a patient who suffered a syncopal episode and their BGL is 36mg/dL, don’t hesitate to treat with IV dextrose or oral glucose (if conscious).

3. Check vitals; stabilize with oxygen or fluid resuscitation prn

The patient’s vitals may clue you in on some treatable things. A low Sp02 can be corrected with oxygen and a low BP can be corrected with crystalloid fluids. Some additional things to consider would be the presence of a fever, which may be masking something more sinister like sepsis.




4. If no response, consider heat injury, anaphylaxis, cardiac, and pulmonary etiologies and treat per protocol

Some of the other rare, life-threatening causes should also be explored if the patient has a prolonged downtime or exhibits unique symptoms. These are some things to look out for:

  • Heat injury
    • Exertion on a hot day
    • Dehydration
  • Anaphylaxis
    • Hx of stings or new medications
    • Presence of hives or mucosal swelling
  • Cardiac
    • Older patient with hx of “heart problems”
    • Abnormal vitals
  • Pulmonary
    • Decreased Sp02
    • Difficulty breathing

5. Cardiac monitoring

ECG can be used to look for anything abnormal with the patient’s heart that may have caused the syncopal episode. You may not be trained in 12-lead interpretation, but some basic things to look for are:

  • Tachycardias (SVT, Afib, etc.)
  • Bradycardias (heart blocks, junctional rhythms)
  • Signs of ischemia (ST-segment elevation/depression)


The prognosis for syncope is usually excellent, so long as no cardiac or pulmonary etiologies are suspected. Most patients will recover on their own without any complications. However, any recurrence of syncopal episodes will definitely require further testing and observation.


Good luck out there!



Brandon Simpson, PA-C
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