INHALATIONAL AGENTS FOR ANESTHESIA INTRODUCTION
Inhaled anesthetics are chemicals with general anesthetic properties that can be delivered by inhalation.
They can be divided into:
- Volatile anesthetic agents
- Volatile agents include
- Sevoflurane
- Isoflurane
- Desflurane
- Methoxyflurane
- Enflurane
- Halothane
- Ether
- Anesthetic gases:
- Nitrous oxide
- Xenon
Volatility refers to the tendency of a liquid to vaporize.
Key Principles of Inhalation Agents:
Key principles:
- The clinical effect of an inhalation agent is dependent on its partial pressure within the CNS
- At equilibrium, the partial pressure in the CNS (PB) equals the partial pressure in blood (Pa), and in the alveoli (PA)
- Reaching equilibrium is rarely achieved in practice as it takes many hours.
- Rate of onset and offset of an inhalation agent are dependent on both physiological and pharmacological factors affecting the transfer of agent.
- From the alveoli into blood
- Into the alveoli
- From blood into the CNS
