My article for the month is: Stokely S., Molfenter SM, Steele CM. Effects of Barium Concentration on Oropharyngeal Swallow Timing Measures. Dysphagia (2014) 29: 78-82.
This study was completed as prior studies suggest that various aspects of the swallowing process, including timing measures may vary depending on the concentration of barium presented to the patient.
Subjects: 20 healthy adults
Given: 3 non cued swallows of 5 ml of barium ("thin" 40% concentration and "ultrathin" 22% concentration).
Longer stage transition durations ("the interval between the bolus head crossing the ramus of the mandible and the onset of hyoid elevation) with the 22% concentration.
Longer pharyngeal transit times ("the interval between the bolus head crossing the ramus of the mandible and closing of the UES") were observed with the 40% concentration.
Longer durations of UES opening with 40% concentration.
Results: "For all temporal measures of interest (stage duration, pharyngeal transit time and duration of UES opening) significantly shorter duration were seen with the 22% concentration than with the 40% concentration."
"The 22% w/v "ultrathin: solution may act more like a true thin fluid such as water than a 40% w/v solution. Although lower concentrations of barium appear less opaque on fluoroscopy, the study by Fink and Ross together with our own use of a 22% w/v concentration for several years, suggests that this concentration is adequate for visualization."
The barium we use will and does effect timing events in the swallow. If the barium solution is more concentrated, we can expect longer timing events in the swallow. We need to be aware of the barium we use and mix it according to manufacturer's directions or use a standardized recipe when assessing the events of the swallow.