Assessment of Aspiration in patients with tracheostomies : Comparison of the bedside colored dye assessment with videofluoroscopic examination

BACKGROUND: Aspiration is a serious clinical concern in patients with long-term artificial airways. The purpose of this study was to determine the reliability of a bedside colored dye assessment of aspiration in tracheostomized patients and to determine its comparability to a more sophisticated videofluoroscopic study. METHODS: This was a prospective, blinded comparison study conducted in a large, urban, university teaching hospital. We studied 20 consecutive patients who underwent tracheostomy for bronchial hygiene needs and who were referred for videofluorographic evaluation for suspected oropharyngeal dysphagia and possible aspiration. Excluded were patients unable to follow verbal commands and those requiring mechanical ventilatory support. All patients were brought to the videofluorography suite for colored dye assessment for aspiration and videofluorographic assessment of oropharyngeal swallow. A nurse, blinded to the results of videofluorographic swallow study, performed colored dye assessments for aspiration. Speech-language pathologists, blinded to the results of the colored dye assessments, interpreted simultaneous (preliminary) and subsequent complete (final) videofluorographic evaluations of swallow. RESULTS: The colored dye aspiration assessments and the videofluoroscopic studies were compared for the frequency of aspiration detection. Sensitivity and specificity were determined using standard methods. Seven patients showed no aspiration on either the colored dye test or videofluoroscopic examination. Eight patients were judged to aspirate by videofluorography but not by the colored dye test. Five patients were judged to aspirate by both the colored dye test and videofluorography. The data indicate that the colored dye test for aspiration carries a low sensitivity of 38% (95% confidence interval = ± 7%), but a high specificity of 100%. The videofluoroscopic study detected a significantly greater frequency of aspiration than did the colored dye test (p < 0.01). CONCLUSIONS: The colored dye test for aspiration can provide useful information when positive, but because there is a significant false negative rate, decisions made on the basis of a negative test must be made with caution.