For operations that require anesthesia, health professionals typically recommend patients do not eat or drink for at least several hours before the procedure. Making sure that the stomach, digestive tract, and bladder are empty before being given anesthesia can prevent a few dangerous complications, most notably vomiting during or after the operation. The amount of time that a patient should not eat or drink varies by procedure and the preferences of the health care professional. In addition to not eating before surgery, a patient should also have a relatively light, healthy last meal before beginning the fast and not smoke or drink alcohol. Although not eating is beneficial and necessary in many instances, emergency situations can occur where this guideline is not followed.
Anesthesia is notorious for causing nausea and vomiting, and eating before surgery only makes this problem worse. If the patient vomits while being anesthetized, there is a risk that the vomit could be inhaled into the lungs, which can be extremely dangerous and sometimes fatal if not caught in time. During the procedure, vomiting or stomach reactions could also interfere with the anesthesiologist's equipment or the site of the operation. Feeling nauseous or vomiting when waking can also lengthen recovery times and make an already uncomfortable patient that much worse.
If you're having an operation on part of the digestive system — especially the stomach, small intestine, or colon — it's important that all of these organs are as empty as possible. Food in the intestines, for example, could make it difficult for the surgeon to see the area clearly and interfere with his or her tools. Partially digested food can also leak out, contaminating other parts of the body and potentially causing infection.
How Long to Abstain
Most surgeons recommend not eating or drinking most fluids for eight to 12 hours prior to surgery. You can usually drink clear liquids like water, apple juice, or chicken broth, but should stop drinking anything four hours beforehand. These guidelines will vary depending on the type of surgery taking place; for example, procedures involving the bowels or intestines generally require that a patient not eat for at least 12 hours, ensuring the digestive system is empty. These guidelines may also vary by patient age or overall health.
The Last Meal
You should eat a light and healthy meal before you are supposed to begin fasting prior to surgery. Avoid heavy foods with a lot of unhealthy fats, as they take a long time to digest; for example, loading up on pizza the night before an operation is not a good idea. You should also not chew or suck on candy because, although they may seem harmless, they can still result in complications.
The surgeon or hospital may give you specific instructions on what you can or cannot eat before you begin your pre-surgery fast. It's important that you follow these instructions. Often, a "low residue" diet will be recommended because it moves through the digestive system quickly and completely. This may include foods like lean meat, crackers or white rice, soft bananas, and well cooked vegetables without the skin. Raw fruits and vegetables, whole grains, and dairy products should usually be avoided.
Smoking and Alcohol
As difficult as it may be for smokers to not smoke prior to going under the knife, it is recommended that they do. Studies show that recovery times are greatly reduced if smokers refrain from tobacco use for at least 24 hours before surgery. When an operation is scheduled several weeks or months in advance, completely quitting tobacco use will also drastically decrease how long it takes the patient to recover.
Experts also recommend that people do not consume alcoholic beverages at least a week before an operation in most cases. Alcohol weakens the body's ability to fight infection and can slow down the recovery time. Studies also suggest that patients who drink regularly are more likely to have complications after surgery.
Vitamins, Supplements, and Medications
In most cases, all vitamins and herbal supplements should be stopped one to two weeks before the operation. Some supplements, including vitamin E, garlic, and ginkgo, may cause bleeding problems, for example. If you're taking any nutritional supplements, let your health care provider know well in advance of your procedure.
You should also tell your medical provider about any medications you are on, including over-the-counter drugs. Many medicines can affect increase bleeding, raise or lower blood pressure, and even make anesthesia last longer. Aspirin and ibuprofen should not be taken two weeks before surgery. Ask your health care team if you should continue taking any prescription drugs.
Ultimately, the restrictions on eating before surgery are precautionary measures. Obviously, emergency operations are performed on people who have eaten before the procedure, and when the choice is between saving a patient's life or waiting, the surgery will go forward. However, for elective or scheduled procedures, eating before surgery should be avoided. If you do end up drinking or eating for any reason, tell the surgeon and let the medical team decide whether or not to move forward.