Your doctor’s instructions for the night before surgery serve an important purpose: They are designed to keep you safe. The reason you cannot eat after midnight on the night before surgery is to keep your stomach empty — to prevent your stomach contents from regurgitating into your windpipe when you are under anesthesia. The center will not go through with your surgery if you break this rule because the dangers are serious. Make sure you ask your doctor when he wants you to stop eating and drinking. If your surgery is later in the day, he may allow a light breakfast. It is important to follow the instructions.

Anesthesia makes your muscles relax to the point you do not have control over them. There are various types of anesthesia, and the type your doctor will use for your surgery depends on the surgical need. Local anesthesia involves directly numbing the area the doctor will work on. Regional anesthesia involves blocking all the nerves to a particular limb or area, such as an arm or leg. You may hear this referred to as an epidural block. General anesthesia renders you completely unconscious.

Reasons for Fasting
The reason you must fast the night before a surgery is that general anesthesia makes you unable to protect your own airway. This puts you in danger of vomiting your stomach contents and inhaling, or aspirating, them into your lungs, according to the “Association of Operating Room Nurses Journal.” When you are under general anesthesia, your muscles are relaxed to the point you cannot even breathe on your own, so a tube is inserted into your windpipe to help you breathe. This tube, called an endotracheal tube, also helps keep your stomach contents out of your lungs.

Aspiration Pneumonia
Although it is very rare to aspirate the stomach contents, the consequences of doing so are serious. Aspiration can lead to a condition known as aspiration pneumonia. This type of pneumonia can cause chest pain, bluish skin coloring, cough with green sputum, fever and shortness of breath. However, if you aspirate during your surgery, you will likely have tests performed before these symptoms appear. Blood work, X-rays, CT scans and an exam of the lungs called a bronchoscopy are treatments for this condition. Antibiotics are another possibility, depending on severity.

Acute Respiratory Distress Syndrome
A rare complication of aspiration pneumonia is acute respiratory distress syndrome, or ARDS. Aspiration is uncommon, and getting pneumonia from it is rare. ARDS from general anesthesia is quite rare, but if the aspiration pneumonia does not get proper treatment or does not respond to treatment, the lungs can suffer further injury. Symptoms include labored breathing, multi-system organ failure, low blood pressure and shortness of breath. This condition usually requires an extended stay in the intensive care unit.