The avian respiratory system: implications for anaesthesia.

Anaesthesia is not a natural state for any animal, including birds. The unique anatomic and physiological attributes of the class Aves that have made it possible for birds to inhabit every continent on this planet and to live in a variety of environments, some considered challenging if not inhospitable to mammals, pose challenges to their anaesthetic management. Indeed, it is more challenging than the anaesthetic management of mammals, a reality substantiated by the fact that the risk of anaesthesia-related death of birds is up to 20 times higher than for dogs and cats. This article highlights those anatomic (respiratory system, renal-portal system), physiological (gas exchange, respiratory control mechanisms in respiratory brainstem and peripheral chemoreceptor areas, including intrapulmonary chemoreceptors) and pharmacological attributes (pharmacokinetics and pharmacodynamics) that make anaesthetic management, both inhalant and injectable anaesthesia, of birds challenging, and how those challenges are managed.This article is part of the theme issue 'The biology of the avian respiratory system'.