Anesthesia is the loss of some or all feeling or awareness. An anesthetic is a drug that causes anesthesia. Anesthetics are used during surgery so you don’t feel pain and to help you keep still during surgery. The type of anesthetic you receive depends on the type of surgery and your general health.

An anesthesiologist is a doctor who specializes in giving the anesthetic and managing the medical condition of a person receiving it.

The healthcare team carefully monitors you during surgery, especially when you receive a general anesthetic. They will regularly check your vital signs, including your blood pressure, rate of breathing, heart rate and temperature. They may also monitor the following during surgery:

  • Pulse oximetry may be used to monitor blood oxygen levels.
  • Electrocardiogram (ECG) may be used to check the heart’s rhythm.
  • Blood gases and electrolyte levels may also be monitored.

Types of anesthesia

There are 3 main types of anesthesia. They are grouped based on how much of the body they affect.

Local anesthesia

Local anesthesia numbs the nerves that cause pain in a small area of the body. It is often used for minor surgery, such as biopsies. The anesthetic or drug is usually rubbed on, sprayed onto or injected (with a needle) into the area where you will have the surgery. Using a local anesthetic allows you to stay awake during your surgery.

Regional anesthesia

Regional anesthesia can be used to block feeling in a specific area or part of the body. You will still be awake during the procedure.

A regional anesthetic (drug) may be injected into an area around the spinal cord or peripheral nerves. Where the anesthetic is injected determines which nerves are blocked, and the part of the body supplied by those nerves will be numbed. You may be given one injection, or you may be given the drug slowly over a period of time during surgery.

Examples of regional anesthesia are epidural anesthesia, spinal anesthesia and peripheral nerve block.

General anesthesia

General anesthesia makes you unconscious and free of pain. You can take a general anesthetic by breathing medicine in through a face mask. A general anesthetic may also be given as a drug injected into a vein.

After a general anesthetic is given, a special tube, called an endotracheal tube (ET), is passed through the mouth or nose into the throat. This tube is connected to a machine that helps you breath while you are unconscious. The ET is used to:

  • help keep the breathing passages clear
  • maintain efficient breathing
  • give anesthetic gases and oxygen

The ET is usually removed soon after the surgery is finished and you can breathe on your own. In some cases, it is left in until the person is in stable condition.

Expert review and references

  • American Cancer Society . Surgery. American Cancer Society. American Cancer Society (ACS). Atlanta, GA: American Cancer Society; 2011.
  • Gillespie,T.N. . Surgical Therapy. Yarbro, CH, Wujcki D, & Holmes Gobel B. (eds.). Cancer Nursing: Principles and Practice. 7th ed. Sudbury, MA: Jones and Bartlett; 2011: Chapter 11:pp.232-248.
  • Rosenberg,S.A. . Surgical oncology: general issues. DeVita VT Jr, Lawrence TS, & Rosenberg SA. Cancer: Principles & Practice of Oncology. 9th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2011: Chapter25:pp268-278.