General anaesthesia relaxes the muscles in your digestive tract and airway that keeps food and acid in your stomach and out of your lungs. That's why it's important to follow your doctor's instructions about when to stop eating and drinking prior to surgery (usually nothing after midnight the day before the operation). You'll get specific instructions based on your age, medical condition, and the time of day of the procedure. In most cases, you should start fasting about six hours before your procedure. You may be able to drink fluids, such as coffee, until four hours before your surgery. 

Why is eating before surgery an issue? Because the body normally has reflexes, which prevent food from being aspirated (or inhaled) into the lungs when it's swallowed or regurgitated (thrown up). But anaesthetic medications can suspend these reflexes, which could cause food to become inhaled into the lungs if there is vomiting or regurgitation under anaesthesia.

You should stay off cigarettes for as long as you can before and after surgery. This will help you have the best possible results from your surgery. For example, quitting will reduce the chances you will have problems like a wound infection after the operation. It is especially important that you not smoke the morning of surgery – just like you don’t eat the morning of surgery, don’t smoke.

Many people find that surgery is also an excellent opportunity to quit smoking for good because most people do not have cravings for cigarettes while in the hospital, and your chances of successfully quitting are almost doubled if you try it around the time of surgery.Your doctor may tell you to take certain medications (pre-operative medications) with a small sip of water during your fasting time. Discuss your medications with your doctor.You may need to avoid some medications, such as aspirin and some other over-the-counter blood thinners, for at least a week before your procedure, as these can cause surgical complications.

Some vitamins and herbal remedies, such as ginseng, garlic, Ginkgo Biloba, fish oil or others, may also keep your blood from clotting normally, interact with other medications or cause other complications. Discuss the types of dietary supplements you take with your doctor before your surgery.If you have diabetes, talk with your doctor about altering your diabetes medication during the fasting period. Usually you won't take oral diabetes medication the morning of your surgery, and if you take insulin your doctor may recommend a reduced dose.If you have sleep apnea, discuss your condition with your doctor. The anaesthetist will need to carefully watch and manage your breathing during and after your surgery.

Before you undergo general anaesthesia, your anaesthetist will conduct a physical examination of your airways, heart and lungs and will talk with you and may ask questions about:

In most cases, your anaesthetist delivers the anaesthesia medications through an intravenous line in your arm, but sometimes the anaesthesia may be given as a gas that you breathe from a mask. For example, children may prefer to go to sleep with a mask. Once you're asleep, a tube may be inserted into your mouth and down your windpipe to ensure you get enough oxygen and to protect your lungs from blood or body secretions, such as from your stomach. You'll be given muscle relaxants before doctors insert the tube, to relax the muscles in your windpipe. In some cases this breathing tube isn't needed, which reduces your chance of a sore throat after surgery. Your doctor may use other options, such as a laryngeal airway mask, to help manage your breathing during surgery. 

If, like lots of people, you're afraid of needles, the good news is that you may not have to get one while awake. Anaesthesiologists often will begin the induction process by using a breathing mask to help you relax. The mask delivers medication to make you sleepy before and during the surgery. That way, you won't be awake when the IV is inserted for general anaesthesia or when a shot is given to numb a certain part or area of the body for local or regional anaesthesia.

A member of the anaesthesia care team monitors you continuously during your procedure, adjusting your medications, breathing, temperature, fluids and blood pressure as needed. Any abnormalities that occur during the surgery are corrected by administering additional medications, fluids and, sometimes, blood transfusions. Blood transfusions may be necessary in some situations, such as complex surgeries. Anaesthetists and other members of the anaesthesia care team monitor your condition and deliver blood transfusions when necessary. However, blood transfusions may involve risks, particularly in people who are older, who have low blood red cell volume or who are undergoing complex heart surgeries.

When the surgery is complete, the anaesthesia medications are discontinued, and you gradually awaken either in the operating room or the recovery room. You'll probably feel groggy and a little confused when you first awaken. Once the operation or procedure is over, you'll be taken to the recovery room, which is sometimes called the recovery room. In the recovery room, nurses and the anaesthetist will monitor your condition very closely for a while to make sure you are making a smooth and comfortable transition from an anaesthetized state to an awakened state.

You may experience common side effects such as: 

If you had general anaesthesia or were sedated, don't expect to be fully awake right away — it may take a while and you may doze off for a bit. It usually takes about 45 minutes to an hour to recover completely from general anaesthesia. In some cases, this period may be a bit longer depending on medications given during or after surgery.

Although every person has a different experience, you may feel groggy, confused, chilly, nauseated, scared, alarmed, or even sad as you wake up. Depending on the procedure or surgery, you may also have some pain and discomfort afterward, which the anaesthetist can relieve with medications. When you have recovered from the anaesthesia, you'll be evaluated to make sure you're ready to leave the recovery room.

In many outpatient procedures, people are allowed to go home soon after the surgery is done, provided they have someone to drive them home. Before you leave the hospital, you'll receive instructions for further recuperation at home and for a follow-up visit with the surgeon. Talk to the surgeon and/or the anaesthetist about what to expect after the surgery and how you can stay as comfortable as possible.

Anaesthesia is very safe. In today's hospitals and surgery centers, highly trained professionals use a wide variety of modern medications and extremely capable monitoring technology to ensure that people are stable and as comfortable as possible before, during, and after their procedure.