The two basic types of anesthesia are general and regional
GENERAL ANESTHESIA
General anesthesia is a state of profound central nervous system (CNS) depression, during which there is complete loss of sensation, consciousness, pain perception, and memory. It has
three components: hypnosis, analgesia, and muscle relaxation.Several different drugs are usually combined to produce desired levels of these components without excessive CNS depression. This so-called balanced anesthesia also allows lower dosages of potent general anesthetics.
General anesthesia is usually induced with a fast-acting drug (eg, propofol or thiopental) given intravenously and is
maintained with a gas mixture of an anesthetic agent and oxygen given by inhalation. The intravenous (IV) agent produces rapid loss of consciousness and provides a pleasant induction
and recovery. Its rapid onset of action is attributed to rapid circulation to the brain and accumulation in the neuronal tissue of the cerebral cortex.
The drugs are short acting because they are quickly redistributed from the brain to highly perfused organs (eg, heart,
liver, kidneys) and muscles, and then to fatty tissues. Because they are slowly released from fatty tissues back into the blood stream, anesthesia, drowsiness, and cardiopulmonary depression persist into the postoperative period. Duration of action can be prolonged and accumulation is more likely to occur
with repeated doses or continuous IV infusion.
An anesthetic barbiturate or propofol may be used alone for anesthesia during brief diagnostic tests or surgical proedures. Barbiturates are contraindicated in patients with acute intermittent porphyria, a rare hereditary disorder characterized by recurrent attacks of physical and mental
disturbances.
Inhalation anesthetics vary in the degree of CNS depression produced and thereby vary in the rate of induction, anesthetic potency, degree of muscle relaxation, and analgesic potency. CNS depression is determined by the concentration of the drug in the CNS. Drug concentration, in turn, depends
on the rate at which the drug is transported from the alveoli to the blood, transported past the blood–brain barrier to reach the CNS, redistributed by the blood to other body tissues, and
eliminated by the lungs. Depth of anesthesia can be regulated readily by varying the concentration of the inhaled anesthetic gas. General inhalation anesthetics should be given only by
specially trained people, such as anesthesiologists and nurse anesthetists, and only with appropriate equipment.
Anda baru saja membaca artikel yang berkategori ANESTHESIA
dengan judul ANESTHESIA. Anda bisa bookmark halaman ini dengan URL https://medipub.blogspot.com/2010/12/anesthesia_15.html. Terima kasih!
Ditulis oleh:
Unknown - Wednesday, 15 December 2010
