Why can you not eat before a scheduled surgery but in the event of say an emergency surgery it’s ok if you’ve eaten?

Question

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

Answer 1

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.