Usefulness of the two-step thickened water test for paste food aspiration in elderly patients with aspiration pneumonia

Abstract

Purpose: To clarify the clinical usefulness of the two-step thickened water test (TTWT), which we developed as a bedside test, for the detection of paste food aspiration in patients with aspiration pneumonia. Subjects and Methods: Eighty elderly patients who were admitted to our hospital under the diagnosis of aspiration pneumonia, were examined. We defined TTWT as the combination of a bedside pretest and a direct swallowing test using thickened water. These patients were examined for swallowing function by TTWT. In addition, the fiberoptic endoscopic evaluation of swallowing (FEES) was performed in order to determine the swallowing function for paste food. Based on the results of TTWT and FEES, we calculated the sensitivity and the specificity of TTWT for the identification of dysphagia for paste food. For comparison, these values were also calculated under the same conditions by using normal water instead of thickened water in the direct swallowing test. Results: The sensitivity and the specificity of TTWT for detection paste food aspiration were 93.9% and 83.0%, respectively. The specificity decreased to 74.5% when normal water was applied in the test, although no decrease in the sensitivity was found. TTWT was completed in less than 10 minutes without any adverse effects in all the patients. Conclusions: TTWT developed by us might be a novel assessment tool for evaluating the risk of aspiration of paste food in the patients with aspiration pneumonia.