Respiratory-swallow coordination in a rat model of chemoradiation.

Abstract

Chemoradiation treatment (CRT) for head and neck cancer (HNC) is associated with postswallow inhale events that elevate the risk of penetration/aspiration. The purpose of this study was to assess the validity of a rat model for investigating the effect of CRT on respiratory-swallow coordination. Videofluoroscopic swallow study was performed on 10 Sprague-Dawley rats 3months post-CRT (3mg/kg Cisplatin, 10 fractions of 4.5Gy/day radiotherapy to tongue base), and 10 naïve controls. We examined the effect of CRT on swallow apnea duration, diaphragm movement, and bolus kinematics. CRT rats had a significant increase in postswallow inhale (p=0.008), which was associated with significantly longer swallow apnea durations, lower diaphragm displacement at swallow onset, and faster pharyngoesophageal bolus speed. The rat CRT model is valid for the study of respiratory-swallow coordination due to the consistency of findings in this study with those reported in clinical CRT studies in HNC.