Characteristics of Anesthetic Agents Used for Induction and Maintenance of General Anesthesia

Edmond I. Eger, II, MD


Am J Health Syst Pharm. 2004;61(20) 

In This Article

Abstract and Introduction

Purpose: The characteristics of ideal intravenous (i.v.) and inhaled anesthetic agents; the rationale for inducing anesthesia with i.v. anesthetics (particularly propofol); therationale for inducing and maintaining anesthesia with inhaled anesthetics; and the advantages and disadvantages of specific inhaled anesthetics, namely, nitrous oxide, desflurane, halothane, isoflurane, and sevoflurane, are discussed.
Summary: Propofol has many characteristics of the ideal i.v. anesthetic, including a rapid, smooth induction of anesthesia and rapid clearance from the body. The use of an i.v. anesthetic such as propofol avoids theclaustrophobia associated with the inhaled route. Inhaled anesthetics are preferred for maintenance of anesthesia because they allow a more precise control of the anesthetic state and do so at low cost. The ideal inhaled anesthetic agent has ample potency and a low solubility in blood and tissues (rapid recovery from anesthesia), resists physical and metabolic degradation, and protects and does not injure vital tissues. It also does not cause seizures, respiratory irritation, or circulatory stimulation or deplete the ozone layer. It has a low acquisition cost. Nitrous oxide potency is too small to produce anesthesia by itself. Halothane is too soluble and poses a risk of severe hepatotoxicity. Desflurane, isoflurane, and sevoflurane are preferred because they have an adequate potency, appropriate solubility, and minimal to no risk for hepatotoxicity.
Conclusion: The utilization choice among desflurane, isoflurane, and sevoflurane is made by weighing specific advantages and disadvantages of each agent. The primary determining factors for use are anesthetic potency and control, rate of anesthesia induction, clearance from the body, and adverse effects.

There are three types of anesthesia: regional and local anesthesia, sedation, and general anesthesia. Regional and local anesthesia allows patients to be awake during a surgical procedure. Sedation is for patients who do not need to be anesthetized completely during a procedure. This article focuses on general anesthetic medications that act reversibly on the central nervous system (CNS) to produce immobility despite noxious stimulation and amnesia. Surgery requires immobility, and most patients desire amnesia for the surgical experience. Other clinically useful effects of general anesthetic agents include unconsciousness, analgesia, suppression of autonomic reflexes (e.g., the increases in blood pressure and heart rate that can occur during surgery), and muscle relaxation.