Effects of Body Positioning on Swallowing and Esophageal Transit in Healthy Dogs

Background Contrast videofluoroscopy is the imaging technique of choice for evaluating dysphagic dogs. In people, body position alters the outcome of videofluoroscopic assessment of swallowing. Hypothesis/Objective That esophageal transit in dogs, as measured by a barium esophagram, is not affected by body position. Animals Healthy dogs (n = 15). Methods Interventional, experimental study. A restraint device was built to facilitate imaging of dogs in sternal recumbancy. Each dog underwent videofluoroscopy during swallowing of liquid barium and barium-soaked kibble in sternal and lateral recumbancy. Timing of swallowing, pharyngeal constriction ratio, esophageal transit time, and number of esophageal peristaltic waves were compared among body positions. Results Transit time in the cervical esophagus (cm/s) was significantly delayed when dogs were in lateral recumbency for both liquid (2.58 +/- 1.98 versus 7.23 +/- 3.11; P = .001) and kibble (4.44 +/- 2.02 versus 8.92 +/- 4.80; P = .002). In lateral recumbency, 52 +/- 22% of liquid and 73 +/- 23% of kibble swallows stimulated primary esophageal peristalsis. In sternal recumbency, 77 +/- 24% of liquid (P = .01 versus lateral) and 89 +/- 16% of kibble (P = .01 versus lateral) swallows stimulated primary esophageal peristalsis. Other variables were not significantly different. Conclusions and Clinical Importance Lateral body positioning significantly increases cervical esophageal transit time and affects the type of peristaltic wave generated by a swallow.