If you were in a car crash and had been eating all day, how is that different from a routine surgery where you weren’t allowed to eat for a certain amount of time before surgery?
Edit: based on some answers, perhaps I should clarify obviously I understand they have to perform surgery in an emergency. My question is more what do they do in an emergency when you haven’t fasted.
Thanks to those with real answers, I never knew about the special tube that could be used. That’s pretty cool.
I’m having surgery tomorrow and can’t eat so was just wondering how they handle food in the stomach during an emergency surgery situation.
In: 2585
Ok a lot of partially correct and some misleading answers. A full stomach increases your risk for aspiration pneumonia while you are being put to sleep and before the breathing tube is inserted. The main methods for preventing the aspiration 1. Having a patient not eat/drink for a period of time prior to surgery or 2. putting the breathing tube in as quickly as possible using fast acting paralytic (classically succinylcholine in the US.) Cricoid pressure used to be used extensively (pressure on the cricoid cartilage to theoretically closes the esophagus and prevents vomiting), however multiple studies have shown it likely doesn’t prevent aspiration and only makes the endotracheal tube more difficult to insert.
The chances of getting aspiration pneumonia and severity mostly depend on the ph of the aspirated contents (lower is worse) and the volume of the contents (more is worse.) That is why pregnant women are given an antacid prior to c sections: they are high risk for aspiration because of the baby pressing in the stomach so you want them to be npo and raise the ph of the stomach contents.
Interestingly, a lot of the science for npo is junk and slowly changing. The initial studies were basically measuring the stomach contents of healthy college kids and then randomly choosing the time when it seems safe. Newer research points to lower risk of aspiration pneumonia when the patient drinks water up to 2 hours before surgery, both due to improved gastric emptying and ph effects.
Anaesthesiologist here.
A lot of good answers already but a clarification here: even in emergency surgery, it really depends on how URGENT it is.
If it’s someone literally about to lose their life, their arm, leg etc, then for sure we proceed, do what we call a rapid sequence intubation and proceed, while accepting the slightly higher aspiration risk.
However if it’s an emergency surgery that can wait for a few hours, eg a deep laceration that needs to be repaired under GA but won’t kill the patient if there is a few hours delay, then we still stick with the fasting as the risk-benefit tips the other way.
TL;DR:
using anesthetic and putting you to sleep can make you vomit if you ate something recently, something you want to avoid during surgery
But
In an emergency situation, its worth the risk (but just to be clear it can still happen and you can choke and die if not take care of)
The risk is the same in both instances but in one you can easily modify it and in the other you can’t and the risk of waiting far out weighs the risk of having eaten.
As many have said, it’s the risk of aspiration which is highest after induction if anaesthesia but before any tube gets inserted for airway protection. Ideally this gap is as short as possible.
The tern rapid sequence induction is used to describe a modified way that anaesthesia is induced and the patient intubated (tube into the windpipe). Usually we give you oxygen, then some drugs to make you “fall asleep” then often another drug that takes a couple of minutes to work that relaxes all uour muscles, including the ones around your throat. Whilst waiting for that last drug to work the team “bag” you, basically meaning they squeeze a bag full of oxygen which is connected to the mask around your nose and mouth, so the oxygen ideally goes into your lungs. Then the tube goes in when the last drug is working. Thing is, the bag squeezing may also make some oxygen fill up your stomach and if it’s full of acid/food/5 pints of lager that stuff can be aspirated into your lungs. This is really bad.
With a rapid sequence induction, and there are variations here, some people don’t do the bagging bit, or do it very gently so that reduces the aspiration risk. The medications given are done so immediately after one another (rather than waiting for the patient to asleep before giving the muscle relaxant, they are all given together) which is one reason why there is more chance of awareness during emergency surgery.
Suction should be immediately available and activated. The drugs chosen may be different. Some countries including the UK also often practice cricoid pressure which is where one person puts their fingers over the front of your throat and applies pressure, so that if any stomach contents do passively rise up, theoretically they get “trapped” in your gullet and don’t easily go down your windpipe. This is controversial however.
Anaesthetist here.
People eat and breathe through the same hole – mouth/pharynx – which then divides into 2 holes: the esophagus for food, and the trachea for air. If food goes down the trachea, the consequences are bad. Pneumonia, or death. We have very sensitive reflexes to make sure that when we swallow food, the trachea is closed off by a flap called the epiglottis. You can’t swallow and breathe at the same time. Don’t try!
If a tiny bit of food or fluid gets past the epiglottis, your body will try to expel it. You have probably all experienced this when a drop of coffee goes down “the wrong way”, and you cough and splutter to get it out of your lungs.
In anaesthesia, we need to put a plastic tube into the airway, sometimes at the back of the throat, sometimes all the way into trachea. To do that, we need to give very powerful drugs to block those protective reflexes.
Without those airway-protection reflexes, any food in your stomach can come up (regurgitate) and go into your lungs. That food might be half digested, which means there are stomach acids mixed in. Those stomach acids can destroy the lung, and the food particles block the lung passages, stopping air from getting in. If you don’t die straight away from that, that food matter could cause lung infections, pneumonia and death at a later date.
This is why we insist on no food before elective surgery. If you have eaten in the previous 6 hours, we will cancel or postpone your surgery until we are sure your stomach is empty. It’s for safety.
Emergency surgery is different. Sometimes even with urgent surgery, we can afford to wait a few hours to allow the stomach to empty naturally, but sometimes we can’t wait because the surgery is urgent.
In that case, we proceed, despite food in the stomach. It’s a calculated risk. We do what is called a “rapid sequence intubation”. This is a relatively risky technique to put a tube into the trachea quickly. We get everything ready, drugs, equipment, suction, skilled personnel. We give the potent drugs in quick succession (rapid sequence) and in bigger doses so they work quicker, aiming to get the breathing tube in quickly, before any stomach contents can come up and go into the lungs. The tube (an endo-tracheal tube) has an inflatable cuff on the end in the airway. When the tube is in place and the cuff is inflated, the trachea is “secured”. Even if food and acid come up from the stomach, it can’t get past the cuff and can’t get into the lungs.
TL;DR anaesthesia with a full stomach is risky. In elective surgery that risk is unacceptable. In the emergency situation, we may take that risk but use techniques to minimise the risk.
Food in your stomach means you risk aspiration on induction of anaesthetic. Generally you fast for about 6 hours beforehand but really that’s an arbitrary number. Patients who have not eaten for days but are on lots of pain killers or have a bowel issue being operated on (or lots of other reasons) may still have a full stomach. We assess the risk of this and then decide how we will manage the airway.
Any emergency surgery where we don’t know if the patient has eaten or not we will assume the patient has a full stomach. In this case we would give rapid doses of anaesthetic and muscle relaxant and put a breathing tube in immediately without bag mask ventilating the patient. But this means everything has to happen rapidly with many team members involved, we risk being unable to get the tube in, and the rapid acting drugs can have unpleasant side effects. If the patient is fasted then we can do it in a more controlled slower way or we can use a different type of airway (e.g. laryngeal mask airway) which does not protect the vocal cords from vomit from the stomach. Much easier to use, less risk of damage to the teeth etc and muscle relaxant is not required to use these so often preferable.
It’s always a balance of risk, aspiration is overall quite rare.
– I’m an anaesthetist
To avoid unnecessary risk during procedures, surgical staff like to control every factor they can.
For example, they like to ensure you’re breathing oxygen, not breakfast.
They’ll take the chance if someone will die without immediate surgery, but if there’s any way it can wait 8hrs, they’ll do it when the patient has an empty stomach.
The big risk for food and drink with surgery is you potentially vomiting while under anesthesia and then breathing it in. That’s why you’re told not to eat anything. Also, if you come to an ER and there is at all a chance that you’ll need anesthesia, we will not let you eat or drink anything until we know that’s not on the table anymore to reduce the risk as much as possible. This is why if you ask a registrar like me for some water, we always say we’ll check with your nurse.
Failing all that (and also if you either forget to not eat before scheduled surgery or can’t not eat for some reason), the anesthesiologist will need to be more vigilant about your airway and take extra steps to protect it from the possibility of vomit.
With emergency surgery you’re already likely dying so they’re willing to work around the risks of you choking on your supper as you’re put under.
You’re already in danger that needs surgery, odds are you’re not gonna breathe in a few minutes anyway if they don’t operate.
But for scheduled surgery if you just don’t eat that’s a lot less work for them to keep you alive from choking if you just don’t eat beforehand.
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