Listen to the Cancer.Net Podcast: Anesthesia - What to Expect , adapted from this content.
Guest Editor: Cancer.Net acknowledges the assistance of Guest Editor, John F. Dombrowski, MD, in the review of this article. Dr. Dombrowski is an anesthesiologist and member of the American Society of Anesthesiologists Board of Directors.
A person may undergo anesthesia for a number of reasons. People living with cancer can expect to receive anesthesia for some diagnostic procedures, such as colonoscopies and upper endoscopies, as well as for surgical procedures. Derived from the Greek word “anaisthesis,” meaning without sensation, anesthesia allows a patient to undergo a procedure without feeling pain and other sensations. In some cases, it makes the patient unconscious.
Although there are several different types of anesthesia, all techniques involve giving drugs that interfere with the nervous system to reduce sensation. The most common types are described below.
Types of anesthesia
Local anesthesia. Local anesthesia, also called a field block, is injected in the area where the procedure is being done. It is typically used only for small procedures, such as a breast biopsy or the removal of a mole. Local anesthesia generally lasts for a short time, such as a few hours.
Regional anesthesia. Regional anesthesia, also called a regional block, is a type of anesthesia that is injected into a group of nerves, numbing one part of the body. Sometimes, it provides pain relief in the hours after surgery to allow a gradual recovery. Two common types of regional anesthesia are:
- Peripheral nerve block, which blocks pain to areas such as the arms, hands, legs, feet, or face
- Epidural and spinal anesthesia, which blocks pain in areas such as the abdomen, pelvis, rectum, or lower limbs
Monitored anesthesia care (MAC). MAC, also called conscious sedation, is a form of anesthesia often used in combination with a local or regional anesthesia. It minimizes pain and discomfort while allowing the patient to speak and respond to the medical care provider.
General anesthesia. General anesthesia makes a person unconscious and blocks any pain during surgery, leaving little or no awareness or memory of the procedure. It can be given intravenously (through the vein), through inhalation, or through a combination of both. This type of anesthesia is typically used only for surgical procedures.
The anesthesia team
The anesthesia care team is a group of physicians, nurses, and other medical professionals who are responsible for the patient's comfort and well-being before, during, and after a procedure. The anesthesia care team is led by an anesthesiologist, a doctor who specializes in giving anesthesia and related care. Other members of the anesthesia care team may include anesthesia residents (doctors who are training to become anesthesiologists), certified registered nurse anesthetists (CRNAs; registered nurses trained in anesthesiology), and anesthesia assistants (health care professionals who have undergone graduate-level training in safe, high-quality anesthesia care and advanced patient monitoring techniques).
What to expect with general anesthesia
If you will be receiving general anesthesia for a diagnostic test or a surgery, knowing what to expect can help ease your mind about the experience and guide your preparations.
Before general anesthesia
Before undergoing anesthesia, you will meet with an anesthesiologist or CRNA for a preoperative interview to provide information that will help the doctor select the best and safest anesthetic for you. You will be asked about your health history; use of prescription and over-the-counter medications, vitamins, and herbal supplements; allergies; and previous experiences with anesthesia. It is important to answer these questions as accurately and honestly as possible. In some cases, you may be asked to fill out a questionnaire before the interview to help guide this discussion.
Because general anesthesia disrupts the body's ability to keep food and drink in the stomach, you will receive instructions about when to stop eating and drinking. In most cases, you will be told to begin fasting about six hours before the planned procedure.
In addition, you will be told whether you will need to temporarily stop taking any of your current medications that would interfere with the anesthesia or the procedure.
During this interview, consider asking any of the following questions related to the anesthesia or the procedure:
- Do I have a choice about the type of anesthesia I will have?
- What are the risks and complications with each type of anesthesia?
- What can I do to prevent or minimize these risks and complications?
- Do I need to have any tests before undergoing anesthesia?
- Can my family come with me to the operating room?
- How will I be cared for before, during, and after my procedure?
During general anesthesia
The medication for general anesthesia may be given through an intravenous (IV) line into a vein in the arm, as a gas inhaled through a mask, or through a combination of both. The general anesthesia typically causes you to become unconscious in less than one minute. At this time, the anesthesia care team may also choose to give other drugs designed to relax you or reduce the risk of post-operative vomiting or pain.
In the operating room, the anesthesia care team will attach monitoring devices to provide information about your vital signs, such as temperature, blood pressure, and heart rate. These will be closely monitored by the care team throughout the procedure. If any undesirable changes occur, the team will stabilize the vital signs by giving additional anesthesia, sedatives, fluids, or other therapies.
During this "maintenance phase" of the anesthesia while you are undergoing the procedure, the anesthesia care team will also monitor your level of consciousness. The anesthesiologist may choose to give additional medication to increase the depth of the anesthesia, provide additional pain relief, or further relax the muscles to help the surgeon complete the procedure.
After general anesthesia
After the surgery has ended, the anesthesiologist will gradually discontinue the anesthesia and provide any other medications necessary to help you regain consciousness. These may include drugs designed to reverse the effects of the muscle relaxants given during surgery. You will then likely be transferred to a recovery room or post-anesthesia care unit, where specially trained nurses will monitor your condition.
After the anesthesia has worn off, you will likely feel groggy and sleepy, and you may even experience a temporary period of mental confusion. In addition, you may experience nausea, vomiting, or chills. If you were intubated (given a tube that is inserted into the mouth and down the airway to help you breathe during surgery), you may also experience dry mouth or a sore throat.
Because your reaction speed and judgment may be temporarily impaired, you should not plan to drive a car or operate heavy machinery for at least 24 hours after waking from anesthesia and avoid making any important decisions during this period. In addition, ask your doctor how long you need to wait before taking your regular medications again to ensure that they do not interfere with any anesthetic drugs or other chemicals remaining in the body.
After anesthesia, your body may have trouble digesting heavy foods, leading to further discomfort. With the doctor's approval, first try to consume liquids, followed by light foods, such as broth or soup, yogurt, gelatin, toast, crackers, or plain rice.
Beyond these minor, manageable side effects, rare complications of anesthesia include serious injury and death, which are greater risks for patients who are elderly or who have severe heart or lung disease. Another rare complication (occurring in one or two out of every 1,000 people) is anesthesia awareness; this means that a person briefly is aware of his or her surroundings during the procedure. Patients who are undergoing emergency surgery; have a long history of anticonvulsant, opiate, or tranquilizer use; have cardiovascular problems; or consume alcohol daily are at increased risk for anesthesia awareness. For most people, though, anesthesia causes no harm.
If at any point during recovery you have questions or feel that your recovery is not progressing as it should, contact your doctor or the facility where you were treated for additional advice.
American Society of Anesthesiologists: Lifeline to Modern Medicine 
Last Updated: September 15, 2011