Standardized Barium Stimuli
It is important to try to perform videofluoroscopy using standardized barium stimuli, so that the same contrast is visible on every exam. The barium calculator on this website is intended to help clinicians prepare barium in a standardized way.
Barium products typically come either in a pre-mixed suspension or as a powder that is intended to be mixed with water. The weight to volume (w/v) concentration of the barium (in grams of barium per ml of fluid) determines both the opacity (i.e. darkness) of the barium on the image and the likelihood that the barium will leave a coating on the mucosa of the oropharynx. For oropharyngeal swallowing examinations, a low-density barium of 20%-40% w/v concentration is considered desirable to ensure visibility of barium on the x-ray image while minimizing coating of the walls of the oropharynx. For further information about the differences between 20% and 40% w/v concentrations, please refer to our publications about barium concentration at: https://link.springer.com/content/pdf/10.1007/s00455-013-9476-7.pdf and https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3921461/
In the United States, Varibar® is a product line distributed by Bracco that is specifically intended for oropharyngeal swallowing examinations. Varibar® comes in a 40% w/v barium concentration and several different consistencies, which are labelled according to the National Dysphagia Diet (the diet texture nomenclature used in the United States from 2002-2017): Thin, Nectar-thick, Thin Honey-thick, Honey-thick and Paste (Pudding-thick).
IDDSI, the International Dysphagia Diet Standardisation Initiative (www.iddsi.org) is a new international framework for labelling diet consistency, which is being implemented in North America and many other countries around the world over the next 2 years. Information about how the Varibar® products map to the new IDDSI framework can be found on the IDDSI website.
Unfortunately, Varibar® is not currently approved for clinical use outside the United States. Consequently clinicians in other countries are faced with the challenge of trying to prepare standardized stimuli using other barium products. This website provides guidance on how to do this.
Notice to Clinicians Preparing Barium Stimuli
Mixing barium preparations in a way that differs from the manufacturer’s label or using them in a different examination context constitutes an “off-label” use of the product. Clinicians are advised to check product labels for intended use and to explore the implications of off-label use with their employers and local regulatory bodies.
If you are preparing barium stimuli in an off-label fashion, we would still strongly recommend that you use water as the liquid to which barium is added. Many barium sulfate powders include non barium ingredients that facilitate good suspension of the barium powder in a liquid medium. These ingredients may include gums or starches. Consequently, it is important to be aware that interactions may occur between the ingredients of barium sulfate powders and thickening agents in pre-thickened liquids, or between these ingredients and proteins or other components of liquids such as milk or nutritional supplements. These interactions may include further thickening or thinning, depending on the particular ingredients involved, and therefore introduce a risk that the flow properties of the barium that is used in an assessment may not match the flow properties of the liquids provided to patients on their diets.
We strongly recommend that whenever you prepare liquid barium, you run a flow test to confirm the consistency of the product you have prepared. Instructions for the IDDSI Flow Test are outlined as part of the Barium Calculator instructions.