title: Viscosity of thickened fluids that relate to the Australian National Standards.
abstract: In 2007, Australia published standardized terminology and definitions for three levels of thickened fluids used in the management of dysphagia. This study examined the thickness of the current Australian National Fluid Standards rheologically (i.e. viscosity, yield stress) and correlated these results with the "fork test", as described in the national standards.
  
  
  
  Clinicians who prescribe or work with thickened liquids and laypersons were recruited to categorize 15 different thickened fluids of known viscosities using the fork test. The mean apparent viscosity and the yield stress for each fluid category were calculated.
  
  
  
  Clear responses were obtained by both clinicians and laypersons for very thin fluids (< 90 mPa.s) and very thick fluids (> 1150 mPa.s), but large variations of responses were seen for intermediate viscosities. Measures of viscosity and yield stress were important in allocating liquids to different categories.
  
  
  
  Three bands of fluid viscosity with distinct intermediate band gaps and associated yield stress measures were clearly identifiable and are proposed as objective complements to the Australian National Standards. The "fork test" provides rudimentary information about both viscosity and yield stress, but is an inexact measure of both variables.
authors.affiliation: a School of Chemical Engineering, The University of Queensland , St Lucia , Australia and.
authors.forename: Enrico
authors.initials: E
authors.lastname: Karsten Hadde
authors.affiliation: b School of Pharmacy, The University of Queensland , St Lucia , Australia.
authors.forename: Julie
authors.initials: J
authors.lastname: Ann Yvette Cichero
authors.affiliation: a School of Chemical Engineering, The University of Queensland , St Lucia , Australia and.
authors.forename: Timothy
authors.initials: T
authors.lastname: Michael Nicholson
mesh_terms: D000328:Adult; D001315:Australia; D001628:Beverages / Q000032:analysis*; D003680:Deglutition Disorders / Q000628:therapy; D005260:Female; D005503:Food Additives / Q000737:chemistry*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D012212:Rheology / Q000379:methods*; D014783:Viscosity; D055815:Young Adult
chemical_list: D005503:Food Additives; D011135:Polysaccharides, Bacterial; C002563:xanthan gum
keywords: Dysphagia; fluid standards; thickened fluids