Aspiration-related respiratory syndromes are well recognized in humans. About half of healthy adults aspirate without apparent clinical consequence. Understanding the frequency and severity of reflux and microaspiration in healthy individuals is critical to determining their role in respiratory disease pathogenesis. In dogs, analogous information is lacking. The objective of this pilot study is to use scintigraphic reflux studies to investigate frequency, location, and duration of reflux and aspiration events in healthy dogs.

Healthy dogs without aero-digestive symptoms within the preceding 6 months were fed a meal containing (3mCi) colloidal 99m-technetium phytate (99mTcP). Time activity curves (TACs) were quantified over the pharynx and three esophageal zones at 5 and 30 minutes post-ingestion. Static images of the lungs were obtained at 2 and 18 hours to evaluate for aspiration. Reflux was characterized by counts exceeding background activity by 200%. Data were reported descriptively as median and range.

Five healthy adult dogs (median 4 yrs, range 3–9 yrs) were enrolled. All dogs had >1 reflux event (median 3, range 2–4, total 15) over the 5 minute dynamic collection period. Reflux was limited to distal esophageal reflux with rising (n=1; reflux with failure of clearance) and falling (n=14; reflux with appropriate clearance) TACs. Pharyngeal contamination was identified in one dog. Aspiration was not observed in any dog.

In dogs, scintigraphic reflux studies can document reflux and may complement videofluoroscopic swallow studies and esophageal pH monitoring. Reflux, but not aspiration, is common in healthy dogs and must be considered during interpretation of results in clinically affected dogs.

Disclosures

Disclosures to report.