Introduction

• Following anesthetic induction Anesthetic induction: overview , administration of further anesthetic drugs is needed to maintain anesthesia, except for very short procedures.
• Maintenance can be achieved using inhalational or intravenous techniques.

Aims

• Adjust patient depth to lightest level of anesthesia compatible with patient safety and good operating conditions.
• Adjust actual dose of anesthetic administered to correspond with the degree of reflex response to surgical stimulation.

Components of anesthesia

• The Anesthesia Triad:
  • Narcosis: unconsciousness.
  • Analgesia Analgesia: overview : prevent pain in the conscious patient; prevent autonomic reflexes in the unconscious patient.
  • Muscle relaxation Muscle relaxant: overview.
• Each component can be produced on its own (local blocks, potent analgesia).
• Balanced anesthesia is the use of all three components, each produced to the degree required for the procedure in progress.
  Either All three components can be produced by one single agent, eg halothane.
  Or The three components can be produced by a combination of agents.
• This generally allows a lower dose of each of the agents to be used than if any one agent is relied upon to provide all three components of the triad on its own.

Maintenance by inhalational anesthesia

Maintenance by intravenous techniques

Analgesia during anesthetic maintenance

Muscle relaxation during maintenance

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.