Anesthesia
Types of Anesthesia
Anesthesia involves the use of medicines to block pain sensations (analgesia) during surgery and other medical procedures. Anesthesia also reduces many of your body's normal stress reactions to surgery.
The type of anesthesia used for your surgery depends on:
- Your medical history, including other surgeries you have had and any conditions you have (such as diabetes). You will also be asked whether you have had any allergic reactions to any anesthetics or medicines or whether any family members have had reactions to anesthetics.
- The results of your physical examination. A physical exam will be done to evaluate your current health and identify any potential risks or complications that may affect your anesthesia care.
- Tests such as blood tests or an electrocardiogram (EKG, ECG), if needed.
- The type of surgery that you are having.
- You need to be able to lie still and remain calm during surgery done with local or regional anesthesia.
- Young children usually cannot stay still during surgery and need general anesthesia.
- Adults who are extremely anxious, in pain, or have muscle disorders also may have difficulty remaining relaxed and cooperative.
- Some surgical procedures require specific positions that may be uncomfortable for long periods if you are awake.
- Some procedures require the use of medicines that cause muscle relaxation and affect your ability to breathe on your own. In such cases, your breathing can best be supported if general anesthesia is used.
Based on your medical condition, your anesthesia specialist may prefer one type of anesthesia over another for your surgery. When the risks and benefits of different anesthesia options are equal, your anesthesia specialist may let you choose the type of anesthesia.
Anesthesia methods
There are several ways that anesthesia can be given.
- Local anesthesia involves injection of a local anesthetic (numbing agent) directly into the surgical area to block pain sensations. It is used only for minor procedures on a limited part of the body. You may remain awake, though you will likely receive medicine to help you relax or sleep during the surgery.
- Regional anesthesia involves injection of a local anesthetic (numbing agent) around major nerves or the spinal cord to block pain from a larger but still limited part of the body. You will likely receive medicine to help you relax or sleep during surgery. Major types of regional anesthesia include:
- Peripheral nerve blocks. A local anesthetic is injected near a specific nerve or group of nerves to block pain from the area of the body supplied by the nerve. Nerve blocks are most commonly used for procedures on the hands, arms, feet, legs, or face.
- Epidural and spinal anesthesia. A local anesthetic is injected near the spinal cord and nerves that connect to the spinal cord to block pain from an entire region of the body, such as the abdomen, hips, or legs.
- General anesthesia is given into a vein (intravenously) or is inhaled. It affects the brain as well as the entire body. You are completely unaware and do not feel pain during the surgery. In addition, general anesthesia often causes forgetfulness (amnesia) right after surgery (postoperative period).
For some minor procedures, a qualified health professional who is not an anesthesia specialist may give some limited types of anesthesia, such as procedural sedation. Procedural sedation combines the use of local anesthesia with small doses of sedative or analgesic agents (painkillers) to relax you.
Medicines used for anesthesia
A wide variety of medicines are used to provide anesthesia. Their effects can be complex, and they can interact with other medicines to cause different effects than when they are used alone. Anyone receiving anesthesia—even procedural sedation—must be monitored continuously to protect and maintain vital body functions. The complex task of managing the delivery of anesthesia medicines as well as monitoring your vital functions is done by anesthesia specialists.
Medicines used for anesthesia help you relax, help relieve pain, induce sleepiness or forgetfulness, or make you unconscious. Anesthesia medicines include:
- Local anesthetics, such as lidocaine (Xylocaine) or bupivacaine (Marcaine), that are injected directly into the body area involved in the surgery.
- Intravenous (IV) anesthetics, such as sodium thiopental (Pentothal), midazolam (Versed), propofol (Diprivan), or fentanyl (Sublimaze), that are given through a vein.
- Inhalation anesthetics, such as isoflurane and nitrous oxide, that you breathe through a mask.
Other medicines that are often used during anesthesia include:
- Muscle relaxants, which block transmission of nerve impulses to the muscles. They are used during anesthesia to temporarily relax muscle tone as needed.
- Reversal agents, which are given to counteract or reverse the effects of other medicines such as muscle relaxants or sedatives given during anesthesia. Reversal agents may be used to reduce the time it takes to recover from anesthesia.
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| Author: | Caroline Rea, RN, BS, MS | Last Updated: February 4, 2008 |
| Medical Review: | E. Gregory Thompson, MD - Internal Medicine John M. Freedman, MD - Anesthesiology | |
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