Pulmonary function in the horse during anaesthesia: a review

The effect of abnormal body position on cardiovascular and pulmonary function in the awake and anaesthetised horse is reviewed. Parameters such as pulmonary shunt, lung volumes, blood gases and alveolar-arterial oxygen partial pressure differences are discussed. Withholding food for 24 hours and mechanical ventilation may be used to improve blood gas values associated with abnormal recumbency during anaesthesia. During prolonged recovery, horses should be encouraged to adopt sternal recumbency.