Originally published, 08/2014
It can happen to anyone: just as you are preparing to place an IUD, your patient faints. Or while giving a routine immunization, a patient falls to the floor for no apparent reason. Those who have been involved with patient care for any length of time know how scary and unpleasant a vasovagal reaction can be for everyone involved. The good news is that once you are a pro at recognizing the signs and symptoms of impending vasovagal syncope, you can almost always prevent fainting and loss of consciousness. You can also give your patients guidance so they can prevent their own vasovagal reactions!
The basics: pathophysiology of a vasovagal reaction
During a vasovagal reaction, patients may feel sweaty and nauseated, have an urgent need to urinate or defecate, and then black out. As scary (and potentially dangerous!) as this can be, a vasovagal reaction is merely a reflex. It begins with pooling of blood in the extremities which decreases peripheral vascular resistance, causing a sudden drop in blood returning to the heart. This triggers a reflex bradycardia—an abnormally slow heart beat—along with a drop in blood pressure. This combination leads to reduced blood flow to the brain and syncope.
One simple step can stop a vasovagal reaction
At any point in the reflex, it can be stopped if the drop in peripheral vascular resistance is reversed by contracting the muscles in the extremities. Isometric contractions of the muscles of the arms, hands, feet, and legs can stop the vasovagal reaction immediately and prevent fainting. Contracting these muscles pushes blood back into the center of the body, interrupting the reflex, and stopping it from progressing to loss of consciousness.
When your patients are about to undergo medical care that may trigger a vasovagal reaction, like having an IUD placed or getting a shot (other common triggers are listed below), giving them a heads up and showing them how to practice the isometric contractions ahead of time can help them stop the reaction themselves. For example, you might say:
“Sometimes people having this done begin to feel dizzy and they can sometimes pass out. If that happens to you it doesn’t mean anything is seriously wrong, but it can be scary. If you start to feel lightheaded, sick to your stomach, sweaty, or if you feel weird in anyway, it may be a sign that you’re about to faint or pass out. You can prevent that from happening by intensely griping the muscles in your hands, arms, feet and legs while releasing the muscles of the belly, bottom, and chest. There is no need to move your arms or legs—just tense the muscles in place. Do you want to go ahead and practice doing that now?”
Be prepared—know the common triggers
Some common events in patient care that can trigger vasovagal reactions:
- Procedures like cervical or uterine biopsies or placement of an IUD
- Pap tests
- Blood draws (or just the sight of blood)
- Injections
- Watching a loved one have a procedure
Be alert for signs or symptoms before a trigger
Maintaining communication with your patient before and during these types of procedures can help you (and your patient) quickly notice signs and symptoms of a vasovagal reaction. Common signs and symptoms include:
- Sweating
- Lightheadedness or dizziness
- Nausea
- Ringing in the ears
- Blurred or reduced vision (spots, dark, grey tone, or tunnel-vision)
- Fatigue or restlessness
- Sudden sensation of feeling hot or cold
- Sudden need to urinate or defecate
- Face looks pale, green, or grey
- Dilated pupils
- Yawning
Is your patient a fainter?
Vasovagal reactions occur more frequently in people who have had one before. So, ask your patients if they have ever fainted or passed out at the sight of blood or when having an injection or procedure. If they say “yes” let them know that they can prevent it happening again if they:
- Drink plenty of water before coming in
- Eat before coming in
- Contract the muscles in their extremities, as described above.
What can you do if a reaction starts?
If someone starts to show signs or have symptoms, you can quickly stop the reaction—pause what you are doing, touch the extremity closest to you, and say:
“Tense these muscles very, very tightly. Now, grip all the muscles in your arms, hands, legs, and feet while releasing the muscles in your belly, your buttocks, and your chest. Keep breathing and squeezing your muscles really hard.”
You can continue to do this for as long as it is necessary, taking a break every 30 seconds or so.
Debriefing with your patient after a vasovagal reaction can reassure them that this is a common phenomenon and help them know how to prevent this from happening to them in the future!
Bottom Line:
Vasovagal reactions are common and can be scary, but they are preventable. Tensing the muscles of the arms, hands, feet, and legs can instantly stop a vasovagal reaction and prevent fainting.
