Detecting pharyngeal post-swallow residue by ultrasound examination: a case series.
OBJECTIVE
Prevention of aspiration pneumonia is a great concern in the era of global aging. The assessment of pharyngeal post-swallow residue is important because remaining food and liquid in the pharyngeal area has a possibility of flowing into the lower airway which can cause aspiration pneumonia. Ultrasound examination has been recently used to assess swallowing disorders because of its noninvasiveness. The aim of this study was to investigate the performance for detecting pharyngeal post-swallow residue using an ultrasound examination by comparing with those using a fiberoptic endoscopic evaluation of a swallowing study as a reference.


METHODS
A linear array transducer attached to the thyroid cartilage to visualize the vocal folds in the sagittal plane. The pharyngeal post-swallow residue in the ultrasound movie was interpreted as a misty hyperechoic area above the vocal folds that remained after swallowing. Nineteen ultrasound images simultaneously obtained with fiberoptic endoscopic evaluation of swallowing study images from nine participants (eight men) with a median age of 70 years at a dysphagia outpatient clinic were analyzed by the montage of swallowing examinations.


RESULTS
Misty hyperechoic areas above the vocal folds that remained after swallowing were detected in 10 ultrasound images. Eight US images out of ten correctly detected pharyngeal post-swallow residue. The sensitivity for detecting pharyngeal post-swallow residue of 19 images from nine participants by US examination was 62%, and the specificity was 67%.


CONCLUSIONS
The proposed detection method of pharyngeal post-swallow residue by ultrasound examination enabled the real-time assessment for swallowing of people with dysphagia. Ultrasound assessment-based daily swallowing care which detects pharyngeal residue will be useful for preventing aspiration pneumonia.
Department of Gerontological Nursing/Wound Care Management, The University of Tokyo;Japan Society for the Promotion of Science, Japan.
Yuka
Y
Miura
Department of Gerontological Nursing/Wound Care Management, The University of Tokyo, Japan.
Gojiro
G
Nakagami
Department of Gerontological Nursing/Wound Care Management, The University of Tokyo, Japan.
Koichi
K
Yabunaka
Department of Gerodontology, Division of Gerontology and Gerodontology, Graduate School, Tokyo Medical and Dental University, Japan.
Haruka
H
Tohara
Department of Gerodontology, Division of Gerontology and Gerodontology, Graduate School, Tokyo Medical and Dental University, Japan.
Koji
K
Hara
Department of Life Support Technology (Molten), The University of Tokyo, Tokyo, Japan.
Hiroshi
H
Noguchi
Department of Life Support Technology (Molten), The University of Tokyo, Tokyo, Japan.
Taketoshi
T
Mori
Department of Gerontological Nursing/Wound Care Management, The University of Tokyo,Japan. hsanada-tky@umin.ac.jp.
Hiromi
H
Sanada
D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003679:Deglutition; D003680:Deglutition Disorders / Q000000981:diagnostic imaging*; D005260:Female; D005336:Fiber Optic Technology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010614:Pharynx / Q000000981:diagnostic imaging*; D011015:Pneumonia, Aspiration / Q000517:prevention & control*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*