title: Effects of powdered versus liquid barium on the viscosity of fluids used in modified swallow studies.
abstract: OBJECTIVE
  To determine if the viscosity of thickened juice mixtures used in modified barium swallow studies significantly changes with the addition of powdered barium. We also describe a test formulation created using liquid barium, which has a negligible effect on juice viscosity.
  
  
  METHODS
  The viscosities of water and standardized honey- and nectar-consistency juices mixed with different amounts of powdered barium were measured by timing the laminar flow of a given initial hydrostatic head of fluid under gravity though an orifice of fixed diameter. Standardized juices were then mixed with a liquid formulation of barium and with measured quantities of water to produce viscosities that more closely equated with those of the standardized juices.
  
  
  RESULTS
  With the addition of powdered barium, viscosity increased in all fluids, most markedly with the nectar-consistency juice. Liquid barium formulations maintained the viscosities of the original thickened juices.
  
  
  CONCLUSIONS
  Rendering juices radio-opaque with barium powder results in dramatic increases in the viscosity of the resulting mixture and compromises diagnostic accuracy. Liquid barium preparations have the advantage that they can be rapidly and accurately dispensed by syringe, and their use does not significantly increase the viscosity of the preparation.
authors.affiliation: Department of Radiology, University of Alberta, 8440-112 St., Edmonton AB T6G 2B7.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Baron
authors.forename: Tim
authors.initials: T
authors.lastname: Alexander
mesh_terms: D001466:Barium Sulfate / Q000008:administration & dosage*; D003287:Contrast Media / Q000008:administration & dosage*; D003680:Deglutition Disorders / Q000000981:diagnostic imaging*; D006801:Humans; D011208:Powders; D011859:Radiography; D014783:Viscosity
chemical_list: D003287:Contrast Media; D011208:Powders; D001466:Barium Sulfate