Variability of swallowing physiology in infants with feeding difficulties: A videofluoroscopic analysis

Abstract

Infants swallow rapidly, increasing the risk that an open airway may coincide with milk transit through the pharynx and result in airway violation. Swallow incoordination is often described in infants with feeding difficulties but it is not known whether this represents pathological incoordination or normal physiologic variability in a developing child. This retrospective study explored the relationship between objective fluoroscopic measures of swallowing variability and aspiration in infants. Methods Videofluoroscopic Swallowing Studies (VFSS) of fifty bottle-feeding infants referred with feeding concerns (aged 5days - 9months) were included. All infants were bottle-fed and recorded mid-feed for a 20-second loop at 30 frames per second. Each swallow in the 20- second loop (n=349 swallows) was analysed using objective digital measures of timing, displacement and coordination (Swallowtail, Belldev Medical, LLC). Measures of swallowing frequency, suck to swallow ratio, residue, regurgitation and penetration-aspiration were obtained. Results Variability in pharyngeal timing and displacement was identified across all infants but did not correlate with aspiration (p>.05). 16 infants (32%) aspirated, however aspiration did not occur on every swallow (rate 10-50% of swallows). Swallowing frequency varied from 1-15 and suck to swallow ratios varied from 1:1-6:1 between infants. More than three sucks per swallow correlated with higher incidence of aspiration (p<.001). Conclusions This exploratory study describes for the first time that pharyngeal timing and displacement variability is present in young children referred with feeding difficulties but does not correlate with aspiration. Greater number of sucks per swallow appears to confer increased risk of airway invasion. Improved understanding of the nature of variability in infants may improve the interpretation of VFSS to go beyond aspiration and improve the management of infant dysphagia.