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.