Indications and Procedures (Magill’s Medical Guide, Sixth Edition)
Anesthetics are given primarily to prevent the pain of surgery during operations. They also are given to reduce fear, relax tissues, and prevent a sympathetic nervous system response to surgery. Some believe, erroneously, that being “put to sleep” with a general anesthetic is the only way an operation can be performed pain-free.
General anesthesia is a type of anesthesia that produces total unconsciousness and affects the entire body. Regional anesthesia, another type of anesthesia, does not produce unconsciousness but allows surgery to be performed without pain by producing loss of sensation in a region of the body—by interrupting the transmission of nerve impulses from the area to be incised.
With general anesthesia, patients receive drugs that are delivered both intravenously and by inhalation. With regional anesthesia, the anesthetic agents are deposited either on the surface of the area to be anesthetized or near a particular nerve or pathway that lies between the area and receptors for painful stimuli that are part of the central nervous system. As a result, transmission of noxious stimuli to the brain is effectively “blocked,” allowing a surgical procedure to be performed without the patient feeling pain. Regional anesthesia is frequently referred to as regional nerve blockade.
Local anesthetics operate in several ways. Those injected near the nerves diffuse into the nerves and bind...
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Uses and Complications (Magill’s Medical Guide, Sixth Edition)
Regional anesthesia has several advantages over general anesthesia. The first is ease of administration: The agents used are injectable, the equipment required is minimal, and the costs are reasonable. Second is relative safety: A localized area of the body can be operated upon while avoiding most of the undesirable and potentially harmful side effects of general anesthesia, such as loss of consciousness and the depression of the cardiovascular and respiratory systems. In addition, advantages include excellent muscle relaxation, which is often required in order to facilitate surgical procedures; improved peripheral blood flow; an antithrombitic effect; a decreased loss of blood in some cases; and postoperative pain relief, a benefit most patients find highly desirable. Regional anesthesia is also utilized in combination with general anesthesia in an effort to increase the benefits of both while decreasing the adverse side effects of each.
Yet regional anesthesia has some disadvantages. First, some operations cannot be performed under regional anesthesia (for example, major surgical procedures involving the brain, heart, and lungs). Second, some patients may be allergic to the local anesthetics. Local anesthetics of the amino ester type may result in allergic reactions because of the metabolite p-aminobenzoic acid. Local anesthetics of the amino amide class are essentially devoid of allergic potential. Many anesthetic...
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For Further Information: (Magill’s Medical Guide, Sixth Edition)
Cousins, Michael J., and P. O. Bridenbaugh, eds. Neural Blockade in Clinical Anesthesia and Management of Pain. 3d ed. Philadelphia: J. B. Lippincott, 1998. This bible of regional anesthesia principles and techniques contains chapters written by experts in the field.
Katz, Jordan. Atlas of Regional Anesthesia. 2d ed. Norwalk, Conn.: Appleton & Lange, 1999. An atlas of nerve block techniques explained in a simple and straightforward manner. The exquisite drawings and meticulous details of the illustrations make this an exceptional text.
Palmer, C. M., M. Paech, and R. D’Angelo, eds. Handbook of Obstetric Anesthesia. 6th ed. Oxford, England: Bios Scientific, 2002. An accessible text that outlines a variety of uses of anesthesia during normal and high-risk pregnancies. Topics include maternal physiology and pain pathways, procedures for cesarean sections, and common clinical scenarios such as preeclampsia, obesity, multiple gestation, and coexisting disease.
Sweeney, Frank. The Anesthesia Fact Book: Everything You Need to Know Before Surgery. Cambridge, Mass.: Perseus, 2003. Designed to help the health consumer become more informed and confident prior to surgery. Covers topics such as how general anesthesia works and how it differs from twilight, spinal, or epidural anesthesia; the credentials one should look for in an anesthesiologist; and questions that are...
(The entire section is 249 words.)
Anesthesia (Encyclopedia of Science)
Anesthesia is the term given to the loss of feeling or sensation. In medical terms, it is the method of decreasing sensitivity to pain in a patient so that a medical procedure may be performed. Anesthesia may be accomplished without the loss of consciousness, or with partial or total loss of consciousness.
There are two kinds of anesthesia: general anesthesia, which affects the entire body and causes a loss of consciousness, and local anesthesia, in which only the area being operated on is affected. With local anesthesia, the patient may be conscious during the course of the operation or given a sedative, a drug that induces drowsiness or sleep.
Anesthesiology is the branch of medicine dealing with anesthesia and anesthetics. Anesthetics can be administered by doctors (called anesthesiologists) or by specially trained nurses (called CRNAs, certified registered nurse anesthetists) working under a doctor's guidance. The development of modern anesthesia has made possible complex operations such as open heart surgery.
History of anesthesia
Methods for lessening the sensation of pain during surgery date back to ancient times. Before the discovery of substances that produced general anesthesia, patients needing surgery for illness or injury had to rely on alcohol, opium (a natural narcotic derived from the opium poppy), or...
(The entire section is 1070 words.)