Hello and welcome to the Zero to Finals podcast. My name is Tom and in this new series on

anesthetics. I'm going to start with an episode on General Anesthesia. And you can find written notes on

this topic at zero to finals.com slash general anesthesia or in the

anesthetics and ICU section of the zero definals surgery book. So let's get straight into it.

There are two main categories of anesthesia, a general anesthesia which involves making the patient unconscious,

and a regional anesthesia, which involves blocking sensation to an isolated area of the body,

for example, a limb. A general anesthetic involves putting the patient in a state of controlled

unconsciousness. It's most often used so that a major surgical operation can be performed.

During a general anesthetic, the patient will be intubated or have a supraglotic airway device

and their breathing will be supported and controlled by a ventilator.

The patient will be continuously monitored at all times immediately before,

during and after a general anaesthetic. Let's talk about fasting. Before a planned general

anesthetic, the patient will have a period of fasting. The purpose of fasting is to make sure that they have

an empty stomach, to reduce the risk of the

stomach contents refluxing into the oropharynx or the throat, then being aspirated into the

trachea or the airway. Gastric contents in the lungs creates an aggressive inflammatory response causing pneumitis, which is

inflammation of the lung tissue. The risk of aspiration is highest before and during intubation

and when the patient is being extubated. Once the endotracheal tube is correctly fitted,

the airway is blocked and protected from aspiration. Aspiration pneumitis and pneumonia are major causes of morbidity or mortality in anaesthetics,

although with planned procedures they're very rare.

Fasting for an operation typically involves six hours of no food or feeds

before the operation and two hours of no clear fluids being fully nil by mouth.

...