Dysphagia as a missing link between post-surgical- and opioid-related pneumonia

Objective Postoperative pneumonia remains a common complication of surgery, despite increased attention. The purpose of our study was to determine the effects of routine surgery and post-surgical opioid administration on airway protection risk. Methods Eight healthy adult cats were evaluated for dysphagia in 2 experiments. 1) In 4 female cats airway protection status was tracked following routine abdominal surgery (spay surgery) plus low-dose opioid administration (buprenorphine 0.015mg/kg, IM, q8-12h; n =5). 2) Using a cross-over design (2 male, 2 female) cats were treated with moderate (0.02mg/kg) or high (0.04mg/kg) dose buprenorphine (IM, q8-12h; n =5) to determine changes in airway protection status or evidence of dysphagia. Results Airway protection was significantly affected in both experiments, but most severely post-surgically where 75% of the animals exhibited silent aspiration. Conclusion Oropharyngeal swallow is impaired by the partial mu-opioid receptor agonist buprenorphine, most remarkably in the post-operative setting. These findings have implications for the prevention and management of aspiration pneumonia in vulnerable populations.