What Canine Patients Are at Risk for Aspiration Pneumonia?

The most severe cases of aspiration pneumonia (AP) occur when the aspirated fluid has particulate matter and a low pH (≤2.5). AP is diagnosed based on history, signs, thoracic radiographs, bacterial cultures of tracheal washes, and necropsy.

This retrospective study of dogs with AP was the largest conducted to date: Records of 240 dogs with AP and 488 control dogs were reviewed. Incidence of AP, diagnosed with thoracic radiographs, was 0.17%. Regurgitation and the administration of hydromorphone during induction were significantly associated with AP. Procedures that carried an increased risk of AP were laparotomy, upper airway surgery, neurosurgery, thoracotomy, and endoscopy. Patients with megaesophagus and preexisting respiratory or neurologic disease were also more likely to develop AP. In dogs with 2 or more of the associated risk factors, 69% developed AP.

For most drugs used during anesthesia and for most procedures that require anesthesia, there is no association with AP; however, for patients with multiple risk factors, the association with AP is high.

Commentary

The incidence of AP is higher in veterinary medicine than in human medicine. As gastroesophageal reflux and AP are rarely immediately apparent, no one particular anesthetic protocol is significantly associated with AP, and the presence of more risk factors predisposes a patient to a greater chance of developing AP. This study could be used as the basis for establishing an AP predictive scoring system similar to one already employed in human medicine.—Andrew Claude, DVM, DACVAA

Source

Prevalence and risk factors for canine post-anesthetic aspiration pneumonia (1999-2009): A multicenter study. Ovbey DH, Wilson DV, Bednarski RM, et al. VET ANAESTH ANALG 41:127-136, 2014.