Inhalation anesthetic agents: Properties and delivery
- Stephen Robert Hays, MD, FAAP
Stephen Robert Hays, MD, FAAP
- Associate Professor, Anesthesiology & Pediatrics
- Vanderbilt University School of Medicine
This topic will review the properties, pharmacokinetics, and delivery of inhalation anesthetics, including the potent volatile agents (sevoflurane, desflurane, isoflurane [and in some countries, halothane]) and one gas (nitrous oxide [N2O]).
Use of anesthesia machines for delivery of these inhalation anesthetics is reviewed separately. (See "Anesthesia machines: Prevention, diagnosis, and management of malfunctions".)
Clinical effects and specific uses for each of the inhalation anesthetic agents are reviewed separately. (See "Inhalation anesthetic agents: Clinical effects and uses".)
MECHANISMS OF ACTION
The precise mechanisms whereby inhalation agents induce general anesthesia are not known, and no single proposed mechanism of action fully explains their clinical effects. (See "Inhalation anesthetic agents: Clinical effects and uses", section on 'Clinical effects'.) Various ion channels including gamma-aminobutyric acidA (GABAA), glycine, and glutamate receptors located in the central nervous system (ie, brain and spinal cord) are affected by the volatile inhalation anesthetics (sevoflurane, desflurane, and isoflurane) [1-4]. Nitrous oxide (N2O) gas is thought to act both by agonism of GABAA receptors and by antagonism of N-methyl-D-aspartate (NMDA) receptors [5,6].
Similarly, the mechanisms by which various intravenous agents are able to induce general anesthesia are not fully understood. (See "General anesthesia: Intravenous induction agents" and "General anesthesia: Maintenance and emergence", section on 'Total intravenous anesthesia'.)To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
- Franks NP, Lieb WR. Molecular and cellular mechanisms of general anaesthesia. Nature 1994; 367:607.
- Franks NP, Lieb WR. Do general anaesthetics act by competitive binding to specific receptors? Nature 1984; 310:599.
- Franks NP, Lieb WR. Where do general anaesthetics act? Nature 1978; 274:339.
- Franks NP. General anaesthesia: from molecular targets to neuronal pathways of sleep and arousal. Nat Rev Neurosci 2008; 9:370.
- Mellon RD, Simone AF, Rappaport BA. Use of anesthetic agents in neonates and young children. Anesth Analg 2007; 104:509.
- Zarate CA Jr, Machado-Vieira R. Potential Pathways Involved in the Rapid Antidepressant Effects of Nitrous Oxide. Biol Psychiatry 2015; 78:2.
- Tanner GE, Angers DG, Barash PG, et al. Effect of left-to-right, mixed left-to-right, and right-to-left shunts on inhalational anesthetic induction in children: a computer model. Anesth Analg 1985; 64:101.
- Hasija S, Chauhan S, Jain P, et al. Comparison of speed of inhalational induction in children with and without congenital heart disease. Ann Card Anaesth 2016; 19:468.
- Boonmak P, Boonmak S, Pattanittum P. High initial concentration versus low initial concentration sevoflurane for inhalational induction of anaesthesia. Cochrane Database Syst Rev 2016; :CD006837.
- de Oliveira GS Jr, Girao W, Fitzgerald PC, McCarthy RJ. The effect of sevoflurane versus desflurane on the incidence of upper respiratory morbidity in patients undergoing general anesthesia with a Laryngeal Mask Airway: a meta-analysis of randomized controlled trials. J Clin Anesth 2013; 25:452.
- Nyktari V, Papaioannou A, Volakakis N, et al. Respiratory resistance during anaesthesia with isoflurane, sevoflurane, and desflurane: a randomized clinical trial. Br J Anaesth 2011; 107:454.
- Lejus C, Bazin V, Fernandez M, et al. Inhalation induction using sevoflurane in children: the single-breath vital capacity technique compared to the tidal volume technique*. Anaesthesia 2006; 61:535.
- Joo HS, Perks WJ. Sevoflurane versus propofol for anesthetic induction: a meta-analysis. Anesth Analg 2000; 91:213.
- Peyton PJ, Chao I, Weinberg L, et al. Nitrous oxide diffusion and the second gas effect on emergence from anesthesia. Anesthesiology 2011; 114:596.
- MECHANISMS OF ACTION
- General concepts
- FACTORS AFFECTING INHALATION ANESTHETIC DELIVERY
- Partition coefficients
- - Blood:gas partition coefficient
- - Brain:blood partition coefficient
- - Oil:gas partition coefficient
- Patient-related considerations
- - Respiratory factors
- - Cardiovascular factors
- Technique-related considerations
- - Concentration effect
- - Overpressurization
- - Second gas effect
- - Use of extracorporeal circulation
- SUMMARY AND RECOMMENDATIONS