Many people occasionally feel lightheaded and may faint or pass out momentarily. Fainting is not the same as being asleep or unconscious. When a person faints, it's usually temporary, and the person can be revived in a few minutes. Someone who becomes unconscious won't respond to attempts to revive him.
Fainting often results when blood flow to the brain is temporarily inadequate as a result of:
Stress
Grief
Overheating
Dehydration
Exhaustion
Illness
Taking certain medications
Standing for an extended period in very hot weather -- especially with locked knees -- can also make people pass out. Inactivity can cause blood to settle in the lower parts of the body, reducing the amount of blood flowing into the brain.
Soldiers standing at attention for long periods are prone to fainting, for example. Certain medications can lower blood pressure to a level that will trigger fainting. People with diabetes can sometimes lose consciousness if their blood sugar levels are too high or too low.
Many people recover quickly from a brief loss of consciousness without any harmful consequences. However, on some occasions, fainting can signal a medical emergency. Don't treat fainting as minor unless you're sure there is no serious underlying cause.
Warning signs
You may be able to tell when someone is about to faint. The warning signs include:
Pale, cool and sweaty skin
Lightheadedness or dizziness
A slow pulse
Nausea
Frequent yawning
Feeling of restlessness
Tightness in the chest
Palpitations
When these signs appear, it is essential to lie down or to sit down and put your head between your legs. That's usually enough to restore adequate blood flow to the brain. If it is very hot, try to move to a cooler location.
Loss of consciousness that lasts for more than a minute or two can be a sign of a severe medical problem, such as:
Seizure
Serious blow to the head
Concussion
Heart attack
Diabetic coma
Epilepsy
Another condition
It is important to treat someone who has fainted or lost consciousness with care to avoid injury. If someone remains unconscious for more than a minute, get help as quickly as possible.
What to do when a victim does not regain consciousness quickly
If you suspect that the cause is excessive heat:
Move the person to a cooler place
Lay the person on her back, elevating the legs eight to 12 inches to help blood flow to the brain
Wipe their forehead with a cool damp cloth
Loosen any tight clothing, especially at the neck and waist
If the person is alert, provide a sports drink or a glass of water with a teaspoon of salt
Make sure there is plenty of fresh air, particularly if you suspect carbon monoxide poisoning
Check the airway, breathing and circulation
Gently tilt the victim's head back, lifting the chin to help air get through the nose and mouth
Put your ear to the person's mouth to ensure you can hear breathing; call 911 and begin cardiopulmonary resuscitation (CPR) immediately if they are not breathing
If the victim vomits, roll them onto their side to prevent choking. Check for injuries, especially if the person has fallen. If the victim is bleeding or injured, begin appropriate first aid.
Use caution
Because it is scary when someone does not quickly regain consciousness, some people panic and do the wrong thing. Remember:
Do not slap, shake or throw water on the victim.
Do not place a pillow under the head.
Do not give anything to drink. One exception may be people with diabetes. If a diabetic person's blood sugar is low, they may need to drink or eat something that will raise it immediately, such as non-diet soda or juice. If blood sugar is too high, the person will need an insulin shot. If they don't have an injection available, call for medical help. If you are unsure if the problem is high or low blood sugar, give the victim something sweet to eat or drink while you wait for help.
Do not attempt to move a person unnecessarily.
Do not try to make an unconscious person sit or stand up.
Never leave an unconscious person unattended at any time. If necessary, ask someone else to call 911.
When to call for help
When someone has fainted, call emergency services if the person:
Is not breathing
Fell from a height or is injured and bleeding
Is known to have diabetes
Is pregnant or is over 50 years old
Feels chest pain, chest pressure, or chest discomfort or has a pounding or irregular heartbeat
Can't speak or has difficulty speaking, can't move or "feel" a limb, is confused, has numbness and tingling or has blurred vision; these are symptoms of a possible stroke
Has convulsions, tongue trauma or loss of bowel control
Fails to regain consciousness after two minutes
What to do
While waiting for help, check the victim's airways, breathing and circulation. You should also check for medical identification indicating a medical problem, such as diabetes, epilepsy or drug allergies. If the person has a medical condition, alert the emergency personnel.
Source: National Library of Medicine
