Fainting is a temporary loss of consciousness. It happens when there isn't enough blood going to the brain because of a drop in blood pressure. Blood pressure can drop from dehydration , a quick change in position, standing or sitting still for a long period, or a sudden fear of something such as the sight of blood.
Physical triggers. Getting too hot or being in a crowded, poorly ventilated setting are common causes of fainting. Sometimes just standing for a very long time or getting up too fast after sitting or lying down can cause someone to faint.
Emotional stress. Emotions like fright, pain, anxiety , or shock can cause blood pressure to drop. This is the reason why people faint when something frightens or horrifies them, like the sight of blood. A person who is hyperventilating is taking fast breaths. Carbon dioxide CO2 levels in the blood falls, causing blood vessels to narrow. Blood flow to the brain decreases, making a person faint. It can all happen very quickly, and although it's not fainting, per se, we can't really tell unless the patient wakes up.
Taking a wait-and-see attitude may be dangerous. Plenty of people lose consciousness due to alcohol use, and we don't call it fainting although passing out still seems appropriate. Besides its obvious sedation effect, alcohol makes you urinate, which will eventually lead to dehydration.
It also dilates blood vessels, which decreases blood pressure. Like shock, losing consciousness due to alcohol is not technically considered fainting, but it may or may not be cause for concern.
It is possible to die from alcohol poisoning , and passing out is a sign of serious intoxication. Other drugs—legal as well as illegal—can knock you out for a variety of reasons:.
Your heart is the pump that forces blood through your veins and arteries. It takes a certain amount of pressure in the bloodstream to keep it flowing. A correctly functioning heart is essential to maintaining adequate blood pressure. If the heart beats too fast or too slow, it can't keep the blood pressure up as high as it needs to be. Blood drains from the brain and leads to fainting.
During a heart attack , the heart muscle can become too weak to maintain blood pressure. To decide if the heart may be the culprit, take a pulse. If it's too fast more than beats per minute or too slow less than 50 beats per minute , suspect that the heart caused the fainting spell. Also, if the patient is complaining of chest pain or other symptoms of a heart attack , assume the heart is too weak to keep blood in the head.
Do you pass out when you see blood? Anxiety, panic disorder, and stress can stimulate the vagus nerve in some people and lead to a loss of consciousness. The vagus nerve stimulates the parasympathetic nervous system, which slows down the pulse rate and lowers blood pressure. Some people are hypersensitive to the vagus nerve, and stimulation can result in loss of consciousness in these people. All by itself, fainting is not life-threatening. However, sudden cardiac arrest looks a lot like fainting and requires immediate treatment.
Whenever you see someone pass out, make sure the person is breathing; if not, call and begin CPR. Once someone faints, get the patient comfortably lying flat. You can elevate the legs to help blood flow return to the brain, but it is generally not necessary and there's some debate on whether it is effective.
Treatment after that depends on the cause of fainting. If this is the first time this person has ever fainted—or if you don't know—call There are some dangerous conditions that can cause fainting and should be evaluated by medical professionals to determine how to proceed.
If the person has a history of fainting, watch the breathing and give them a couple of minutes to wake up. If the person doesn't wake up within three minutes of lying flat, call More important than immediate treatment is to treat the cause of the fainting. Often, the only way to identify the cause is to look at the patient 's chronic medical problems, if any, and recent activities or illnesses.
Collapsing is surprisingly common — at least 1 in 2 people will suffer a collapse at some point in life. We asked leading consultant cardiologist Dr Amanda Varnava what causes someone to collapse and what a GP should do to investigate the problem. There are three main causes of collapse: simple fainting , heart problems , and seizures. When a doctor investigates the cause of collapse, they will always perform an ECG to monitor the activity of your heart.
During this time you are likely to be advised not to drive. In this situation, you are likely to be referred to a neurologist. Fainting is not as worrisome as the other causes discussed above, but still something that should be investigated and mitigated where possible.
Your doctor is likely to suspect simple fainting if:. Usually a diagnosis of simple fainting can be made on these symptoms alone. Treatment in this situation will mainly involve advice on keeping very well hydrated and avoiding caffeine. Dr Amanda Varnava is a leading cardiologist and a highly experienced consultant based in London. Call triple zero for an ambulance if someone: collapses while sitting or lying down has a seizure has chest pain or palpitations develops a sudden, severe headache has problems breathing What is a collapse?
What causes a collapse? Other, more serious, causes of collapse include: a heart attack a stroke a seizure a major illness an injury or accident, especially if there has been a blow to the chest or head a drug overdose alcohol poisoning Collapse treatment If someone collapses, follow these steps. Do not put yourself or others at risk. Remove the danger or the patient. R Response Look for a response from the patient — loudly ask their name, squeeze their shoulder.
S Send for help If there is no response, phone triple zero or ask another person to call. Do not leave the patient. A Airway Check their mouth and throat is clear. If there is foreign material, roll the patient on their side and clear the airway. If there is no foreign material, leave them in the position you find them in and gently tilt their head back and lift their chin to clear the airway.
B Breathing Check if the person is breathing abnormally or not breathing at all after 10 seconds. If they are breathing normally, place them in the recovery position and stay with them. If they are not breathing normally, call an ambulance and start CPR. Continue CPR until the patient starts breathing or until help arrives. Do not leave the patient alone to fetch the defibrillator — let someone else bring it. Collapse self-help Do not drive after you have collapsed. How to prevent a collapse If you are likely to faint, avoid triggers like standing up too quickly or getting dehydrated.
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