Quantifying Bolus Residue and Its Risks in Children: A Videofluoroscopic Study

Purpose Postswallow residue is a clinical sign of swallow impairment and has shown a strong association with aspiration. Videofluoroscopy (videofluoroscopic study of swallowing [VFSS]) is commonly used to visualize oropharyngeal swallowing and to identify pharyngeal residue. However, subjective binary observation (present or absent) fails to provide important information on volume or location and lacks objectivity and reproducibility. Reliable judgment of changes in residue over time and with treatment is therefore challenging. We aimed to (a) determine the reliability of quantifying pharyngeal residue in children using the bolus clearance ratio (BCR), (b) determine associations between BCR and other timing and displacement measures of oropharyngeal swallowing, and (c) explore the association between BCR and penetration-aspiration in children. Method In this single-center retrospective observational study, we obtained a set of quantitative and descriptive VFSS measures from 553 children (0-21 years old) using a standard protocol. VFSS data were recorded at 30 frames per second for quantitative analysis using specialized software. Results Good interrater (ICC = .86, 95% CI [.74, .961], p < .001) and excellent intrarater reliability was achieved for BCR (ICC = .97, 95% CI [.91, 1.000], p = 001). Significant correlations between BCR and pharyngeal constriction ratio and total pharyngeal transit time were reported (p < .05). Using binomial logistic regression modeling, we found BCR was predictive of penetration-aspiration in children, χ²(13) = 58.093, p < .001, 64.9%. Children with BCR of ≥ 0.1 were 4 times more likely to aspirate. Conclusion BCR is a reliable, clinically useful measure to quantify postswallow residue in children, which can be used to identify and treat children with swallow impairments, as well as to measure outcomes of intervention.