Experimental and Computational Investigation of the IDDSI Flow Test of Liquids Used in Dysphagia Management
- PDF / 3,795,660 Bytes
- 12 Pages / 593.972 x 792 pts Page_size
- 65 Downloads / 196 Views
Annals of Biomedical Engineering (Ó 2019) https://doi.org/10.1007/s10439-019-02308-y
Experimental and Computational Investigation of the IDDSI Flow Test of Liquids Used in Dysphagia Management BEN HANSON ,1 RASHID JAMSHIDI,2 ANDREW REDFEARN,1 RYAN BEGLEY,1 and CATRIONA M. STEELE3,4 1
UCL Mechanical Engineering, Torrington Place, London WC1E 7JE, UK; 2UCL Chemical Engineering, Torrington Place, London WC1E 7JE, UK; 3Toronto Rehabilitation Institute – University Health Network, 550 University Avenue, #12-101, Toronto, ON M5G 2A2, Canada; and 4Rehabilitation Sciences Institute, Faculty of Medicine, University of Toronto, 500 University Avenue, Suite 160, Toronto, ON, Canada (Received 5 February 2019; accepted 11 June 2019) Associate Editor Jane Grande-Allen oversaw the review of this article.
Abstract—The International Dysphagia Diet Standardisation Initiative (IDDSI) flow test, using a standard 10-mL syringe, is being adopted in many countries for clinical measurement of the consistency of drinks. The working hypothesis is that thickening drinks to retard flow can be advantageous for individuals who struggle to cope with thin drinks. This study assesses how the IDDSI test relates to rheology and clinical knowledge of physiological flows during swallowing. With no pre-existing analytical solution for internal flow through the syringe, a computational model was designed, incorporating rheometry data from a variety of Newtonian and non-Newtonian liquids. The computational model was validated experimentally across the range of liquids but the technique showed limitations in simulating dripping and cohesiveness. Gum-based liquids which were strongly shear-thinning (0.12 < n < 0.25) showed plug-flow characteristics with 90% of the shear occurring in only 22% of the radial dimension. Shear rates were maximal at the nozzle outlet (> 60 times higher than the barrel) and reached 7400/s for the thinnest gum-based liquid. Shear rheology data alone was unable to describe the flow of these drinks. The flow conditions in the test varied according to the type and consistency of liquid, relating to the desired clinical effect. Keywords—Rheology, Fluid dynamics, Swallowing, International Dysphagia Diet Standardisation Initiative, Non-Newtonian, Thickened drinks, Texture modification.
INTRODUCTION During swallowing, the safe and efficient transport of a liquid bolus depends on a biomechanical process involving up to 26 paired muscles whose contraction is Address correspondence to Ben Hanson, UCL Mechanical Engineering, Torrington Place, London WC1E 7JE, UK. Electronic mail: [email protected]
tailored to the flow properties of a liquid.7 Dysphagia, the term for an impairment to the safety and/or efficiency of swallowing, frequently involves inappropriate timing, strength or coordination of muscle contraction leading to airway invasion or the accumulation of post-swallow residue.7,37 In such situations, thickened liquids are a widely-used intervention, based on the idea that slower flow of these thicker liquids provides the person with extra ti
Data Loading...
