Send the right signals and don’t take a tumble

MY room at the surgery is tucked away around the corner near the treatment rooms. I like it round there — it’s nice and quiet and gives me fast access to the admin area in one direction and the kitchen in the other.

It’s also next to the rooms where the phlebotomists work. This means that, every once in a while, I hear a little shout for some help. Almost always that’s because someone has fainted while having their blood taken.

Fainting is pretty common. In fact, around two in five of us faint during our lifetimes although, touch wood, so far I have managed to avoid this.

But what exactly is a faint? It might first be useful to explore a slighter broader term that is sometimes used interchangeably with the word faint — syncope. This word of Greek origin means “to cut short” and, essentially, applies to any scenario in which there is a sudden loss of consciousness.

This does not necessarily mean a syncope is automatically just a faint. Indeed, there are some fairly serious causes of syncope, including neurological events such as strokes and TIAs (transient ischaemic attacks).

However, most commonly, it is due to our brains suddenly experiencing a loss of adequate blood supply. The brain is a remarkable organ and, to be fair, it does an awful lot of work (in some more than others).

As such, despite making up only two per cent of the body’s mass, it demands around 15 per cent of the cardiac output. In other words, it needs a large and constant supply of blood just to keep things ticking along.

Generally speaking, our body is rather good at adjusting to the different stresses that are placed upon it that might otherwise affect this supply and demand balance.

As we exercise or get a fright, the heart rate increases to get more pumping through the system and redirects blood to the muscles, for example, in case we need to make a quick getaway from danger. Even small differences, such as standing up, need some correction to increase the pressure of the blood so it maintains its supply of the brain against gravity.

Clearly, if a problem arises with the rhythm of the heart (an arrhythmia) then blood supply might not be sufficient to keep one conscious. In such a case, the associated syncope can be sudden and unexpected, and thus likely to be labelled as a blackout by us clinicians, worthy of further investigation.

The term “faint” in the most colloquial of its forms, however, is used to describe something we refer to in the trade as vasovagal syncope. This, too, results in a sudden and temporarily inadequate supply of blood to the brain, but generally tends to be much less serious as it comes about through a natural physiological reaction.

While our bodies increase blood pressure in response to certain things, there is also a mechanism that does the opposite. This is stimulated by the vagus nerve, a large nerve that runs down the centre of our bodies.

In response to signals from the vagus nerve, our hearts slow, our blood vessels widen, lowering the pressure within the system. This can be useful if our bodies are trying to calm down in moments of stress for example.

There are all sorts of scenarios in which one might be more likely to suffer a vasovagal fainting episode. One of the best ways to demonstrate a vagal response is by blowing up a balloon. Blowing against resistance can make people pass out and this sort of straining is also why lots of people tend to faint while on the loo.

Heat is another example. In order to cool itself down, your body widens the blood vessels closest to your skin, diverting blood supply to those areas at the expense of the brain. This is compounded if you become dehydrated as the circulating volume of the blood also drops. Sitting in a warm bath or taking a hot shower has a similar effect and it’s no coincidence that people faint very commonly in such an environment.

Stress or pain can activate the vagus nerve and so, if for example you are Doc Martin and don’t do well with blood, this vagal stimulation might make you feel a bit woozy.

Standing for long periods, alcohol and medication can do the same thing and often if there is a combination of any of the above, you’re much more likely to take a tumble.

If you read a lot of Victorian literature, you might have noticed that the women back then tended to faint and swoon all over the place. Some sources suggest that at least some of this might have been to hold up the delicate stereotype and may not have been completely representative.

Having said that, there was such a thing as a fainting room, to be found in many upper-class dwellings — a place for women to go and recover. In order to meet the fashion standards of the time, women, often on empty stomachs, would be laced into tight corsets and this was no doubt a large factor in the frequency of fainting back then.

But it has also been suggested that certain household poisons may have had a part to play. Arsenic was a common component of certain fabrics and paints at that time and lead was present in many types of make-up too. With all of that to contend with, it’s no wonder that Victorian women fainted so much.

What do I and the phlebotomists do first when someone experiences a vasovagal faint? Well, the first thing is to try and get the blood flowing back to the brain as quickly as possible.

As long as it is safe for you and them to do so, the patient is ideally laid flat and their legs raised in the air so that gravity can give the body a helping hand. A glass of water to get some fluid into the system can help and the key is not to get up too quickly. Too soon and you’re likely to go straight back down again.

Some people who faint can appear to have a seizure — the tonic-clonic whole body shaking that is more commonly associated with an epileptic fit. The way to differentiate is through a combination of various factors.

You’re more likely to feel a faint coming on if bright dots are swimming across the vision, darkening at the peripheries of vision and a pallor that bystanders might notice. If this is happening to you, sit on the floor and put your head in between your legs. You may not lose consciousness fully but, if you do, a faint tends to last no longer than a minute before consciousness is regained. Afterwards, recovery tends to be relatively quick compared to the postictal (post fit) drowsiness an epileptic might experience.

Having said that, it’s worth just highlighting the signs to look out for that might signal a different and more serious cause. I’ve mentioned prolonged loss of consciousness. If someone is failing to come around despite the measures I’ve described, consider a different cause and call for more help.

Obviously, if someone has chest pain, irregular heartbeat, weakness or speech issues in the context of a syncope, it’s best to call 999. Also, if someone is diabetic and on insulin, make sure you consider whether they might be having a hypoglycaemic attack. No harm in giving them a sugary drink, just in case.

You often see in films the use of smelling salts. These are actually ammonium carbonate which, in combination with water, releases ammonia gas that irritates the nose and windpipe. The acrid smell therefore does nothing more than to encourage a bit more alertness in a fainter. While common in Victorian times, they are not used today and don’t actually act upon the underlying cause of a faint. Best therefore to stick to the lying flat with legs in the air technique.

Experiencing someone faint in front of you can be quite scary but as long as you do the simple things, call for help if there are any red flags and, above all, stay calm, you’ll be fine.