I Fainted at the Doctor’s Office! Vasovagal Syncope

You’re at the doctor’s office getting your blood drawn for routine labs. Everything is going fine, but the room is warm, and you start to feel yourself getting even warmer, then lightheaded. Then a little queasy and clammy. Then you develop tunnel vision, and before you know it, you’re waking up on the ground with a bunch of worried people gathered around you. What happened??? You fainted!

Vasovagal Syncope: What is it?

More than likely, what you experienced was something called vasovagal syncope. Vasovagal Syncope (pronounced “Vay-Zoh-VAY-gul SINK-kuh-pee) is actually a pretty common occurrence in the medical world. “Vasovagal” refers to both the vascular system and the Vagus nerve (which controls your parasympathetic nervous system --- the opposing part to your “fight or flight” system). “Syncope” means a sudden loss of consciousness. When people experience vasovagal syncope, it just means that the vagus nerve (more on this below) was trying to do its job, but over-reacted a bit --- causing your blood pressure to drop, resulting in your brain being unhappy (due to lack of blood flow and oxygen) and causing you to pass out!  Symptoms associated with vasovagal syncope include lightheadedness, dizziness, nausea, sweating, and blurry vision.  The symptoms typically resolve completely within 10 – 60 minutes after the start of an episode.

Vasovagal Syncope: Why does it happen?

Way back when we were living among saber tooth tigers, our bodies developed a self-defense mechanism called the “fight or flight” system.  If it looked like we were going to have to fight the tiger then our “sympathetic” nervous system would kick in (like pushing down hard on the gas pedal) and we would get a sudden surge in adrenaline, increased blood flow to our muscles, and a rapid heart rate and respiratory rate, resulting in the sudden ability to have super–human strength, allowing us to fight and occasionally defeat the tiger!

Unfortunately, more often the tiger would rip off one of our arms --- leaving us in a very bad spot. At this point, our “parasympathetic” nervous system might kick in. This part of the nervous system (sometimes called the “rest and digest” system puts a brake on the sympathetic system, causing our blood vessels to dilate, our heart rate to go down, and our blood pressure to drop. If we were lucky, the rate of blood pumping out of our body would slow down maybe even allowing the blood to clot, allowing us to survive to see another day! This system made a lot of sense, in a primitive world….

Fight or flight versus rest and digest: The constant battle in our nervous system

These 2 systems --- “fight or flight” and “rest and digest” --- are still with us today and its when they get out of balance that vasovagal episodes occur. Right before an episode of vasovagal syncope occurs, something triggers the parasympathetic (“rest and digest”) nervous system --- whether that’s the sight of blood or a needle, a blood draw, or any other procedure that the body perceives as a threat. Once an episode starts, it’s hard to stop it!

Vasovagal Syncope: Is it dangerous?

Symptoms and signs of vasovagal episodes are predictable and if recognized quickly, relatively harmless.

Dangers may arise if a vasovagal episode is not recognized for what it is, or if the patient experiencing the vasovagal episode falls and hits their head or injures another body part in the process of falling. Rarely, patients might experience symptoms that appear “seizure-like,” (eyes rolling back, twitching, loss of bladder function) prompting a huge and oftentimes unnecessary neurologic workup!

What can you do if you have experienced or are experiencing a vasovagal episode?  

What to do IN ADVANCE if you are prone to vasovagal episodes:

• Plan ahead!  If you have experienced vasovagal episodes in the past and you are planning on getting your blood drawn or having a medical procedure, let your medical team know in advance that you are prone to these episodes so that precautions can be taken! For instance, if you are getting a blood draw it is probably a good idea to be lying down during the procedure so that if you do feel faint, you will be in a safe position, and will not fall.

• Hydrate --- making sure that you are well-hydrated may help to reduce the chance that you will faint!

• Check with your doctor about possibly holding off on taking a blood pressure medicine or diuretic until after the medical procedure is complete.

• There is some anecdotal evidence that pre-treatment with a benzodiazepine (like valium) will help to reduce the occurrence and severity of procedure-related vasovagal episodes. Ask your doctor if this is an option, even if you’re not someone who is anxious about medical procedures!

What to do if you are IN THE MIDDLE of a vasovagal episode:

• Lie down, legs up!  --- Lie down and put your feet up. This may be all you need.  Your body is trying to get the blood to pool in your legs and if it pools too much your brain won’t be happy and you’ll faint.

• Tense up!   --- if you grip one hand with the other one and straighten your arms while simultaneously trying to pull them away from your body, this may help. Tightening your thigh and calf muscles while simultaneously crossing your legs may also help.

When should you see someone about vasovagal syncope?

The purpose of this article is to describe a very specific form of vasovagal syncope --- medical procedure-related vasovagal syncope.  There are many other types of syncope, so it is important that you discuss any syncopal episodes with your primary care provider, so that appropriate cardiac and neurologic workup can be performed if necessary.  Vasovagal episodes may be due to problems in the cardiac system, vascular system, nervous system, or the endocrine system, and these conditions may be much more serious than the procedure–related syncopal episodes described above.