Hypoxaemia following suspected intubation of the tracheal bronchus of a pig

Abstract

A male, estimated body mass 60 kg, six‐month‐old Gloucester Old Spot pig was anaesthetised, and the trachea intubated for repair of a large umbilical hernia. Following endotracheal intubation and connection to the anaesthetic breathing circuit and machine, cyanosis was noted, and hypoxaemia, with hypercapnia, was later confirmed by arterial blood gas analysis. Differentials for hypoxaemia under general anaesthesia include inadequate delivery of oxygen, hypoventilation, ventilation: perfusion (V:Q) mismatching, diffusion disorders and intrapulmonary shunting. Hypoxaemia was eventually resolved by repositioning of the endotracheal tube, and the remainder of the anaesthesia, surgery and recovery were uneventful. Swine possess a tracheal bronchus which supplies, most usually, the right cranial lung lobe, and the practitioner should be aware of its presence and of the consequences of inadvertent intubation, bypass or blockage of the bronchus of this cranial lung lobe, as well as methods to avoid this complication.

Intubation in Swine: What Recumbency to Choose?

“…Moreover, a tracheal bronchus, ventilating an accessory right lobe, is present in pigs. Even if it does not constitute an obstacle for the endotracheal intubation per se, it can be bypassed or intubated, adding a further challenge to the airway management in this species [ 1 , 5 ]. Despite the high number of pigs undergoing experimental surgery every year [ 6 ], little information is available regarding the most advantageous animal positioning to perform intubation.…”