The accuracy of the modified Evan's blue dye test in predicting aspiration

The modified Evan's blue dye test (MEBDT) is a relatively simple, inexpensive bedside procedure for the assessment of aspiration in the tracheotomized patient. Recent investigations have questioned its diagnostic accuracy. The purpose of the study was to evaluate the accuracy of the MEBDT in predicting aspiration among tracheotomized patients.

Prospective observational study.

In the setting of a long-term acute care hospital, all persons with a tracheotomy tube undergoing a bedside swallowing evaluation between October 1, 2001, and March 31, 2002, were prospectively evaluated. All individuals underwent a MEBDT and a subsequent fiberoptic endoscopic evaluation of swallowing (FEES) using a standardized protocol. The sensitivity and specificity of the MEBDT in predicting aspiration were determined.

Thirty persons were evaluated. The mean age of the cohort was 65 years (SD +/- 11 y). Sixty percent (18 of 30) were men. The sensitivity and specificity of the MEBDT for the entire cohort were 82% and 38%, respectively. The sensitivity of the MEBDT for patients receiving mechanical ventilation was 100% compared with 76% for individuals not receiving mechanical ventilation. The specificity of the MEBDT remained low, regardless of ventilator status (33%-40%).

The sensitivity of the MEBDT in predicting aspiration among individuals in our cohort was 82%. The sensitivity was even higher (100%) when performed on persons receiving mechanical ventilation. These results support the use of the MEBDT as a screening tool for persons with a tracheotomy tube. The specific technique of performing the MEBDT is imperative, and the results of the study must be differentiated from other reports evaluating the MEBDT that use a different test protocol.