Volumes of discrete sips from straws of varying internal diameters

Purpose: In this study, the authors examined mean volumes of discrete sips performed by healthy adults from straws varying in internal diameter. Method: Forty healthy adults sipped water from each of 7 straws varying in internal diameter (0.65-5.00 mm). Bolus volumes associated with 3 discrete sips were recorded under each sip condition. Results: Straw diameter had a significant effect on bolus size, with the smallest diameter straws eliciting the smallest bolus volumes. Bolus volumes did not vary according to age or sex. Considerable intersubject variation was observed, particularly for the straws with the largest diameters. Intrasubject variability across 3 trials was minimal. Conclusions: The findings support the hypothesis that narrower straw diameters are associated with smaller bolus volumes in healthy adults. Additional study is needed to determine whether individuals with dysphagia demonstrate similar patterns of bolus size associated with straws varying in internal diameter and whether such variations have clinical benefit.