Suspected fatal venous air embolism during anaesthesia in a Pomeranian dog with pulmonary calcification

Death occurred in a 1.25 kg, 9-month-old female Pomeranian dog undergoing anaesthesia for surgical repair of partially healed fractures of the radius and ulna.

Following sedation, anaesthesia was induced using thiopentone and maintained with halothane in oxygen. An acute decrease in the dog's end-tidal carbon dioxide (EtCO2) measurements was noted approximately 50 min after induction, immediately following delivery of a 5-ml bolus of lactated Ringer's solution (LRS) administered to flush a small (0.06 ml) volume of fentanyl via a pre-placed intravenous (I/V) catheter. Venous air embolism (VAE) was suspected and the dog died despite interventive therapy. On post-mortem examination, several air bubbles were noted when the right ventricle was opened under water. Histologically, the kidneys appeared abnormal with immature glomeruli, and the lungs appeared diffusely mineralised. The origin of the air was probably small bubbles and microbubbles that may have been present in the extension set and 20 ml syringe used for the administration of fentanyl and I/V fluids to the dog.

Renal dysplasia and diffuse pulmonary calcification, with VAE as the probable cause of death.

In this case of VAE-associated anaesthetic death, it is further speculated that underlying pulmonary disease, in the form of pulmonary calcification, may have contributed to an increased sensitivity to the adverse effects of VAE.