Induction

Induction is the initiation of sleep by chemical hypnosis. It is commonly the second stage in a general anaesthetic protocol. Prior premedicative amnesics aid in negating recall of induction.

There are several routes for the anaesthetic induction, but intravenous and inhalational are by far the most common. The indications for inhalational induction include:

• patients with, or with the potential for, airway obstruction
• children, where requested

With intravenous induction, a small test dose of agent may be given first in order to determine whether inadvertent arterial cannulation has occurred. Inhalational induction begins with a nitrous oxide/oxygen mixture via a mask. The concentration of the anaesthetic agent is increased slowly so as to produce smooth transit into sleep - monitored continually with vital signs and reflex responses.

For all forms of induction, there should be as little stimulation of the patient as possible.