ABSTRACT
Inhalational anaesthetic agents are frequently used to keep patients asleep during an operation and occasionally used as induction agents in special circumstances. The most commonly cited theory is the Meyer–Overton hypothesis; this suggests that inhalational agents dissolve in the lipid membranes of the neurones causing anaesthesia. Minimum alveolar concentration (MAC) in simplistic terms is used to describe the potency of inhalational anaesthetic agents. The lower the MAC the greater the potency of the agent. Onset of anaesthesia, when using inhalational agents, occurs when the concentration of the agent in the alveoli reaches equilibrium with the concentration in the blood. Sevoflurane is one of the most commonly used agents as it has many desirable properties, which make it uncomplicated, safe and efficient to use. Nitrous oxide should be avoided in patients with raised intracranial pressure due to its significant effects on cerebral blood flow.
