Diagnostic Accuracy of the Modified Evan's Blue Dye Test in Detecting Aspiration in Patients with Tracheostomy: A Systematic Review of the Evidence

Oropharyngeal aspiration (OPA) is a common occurrence in patients with tracheostomy. The modified Evan's blue dye test (MEBDT) is an easily administered bedside procedure for the assessment of tracheostomised patients. However, studies evaluating the diagnostic accuracy of the MEBDT reach conflicting results. Therefore, we conducted a systematic review to determine the overall accuracy of the MEBDT in detecting OPA in adults with tracheostomy. The search strategy incorporated searching electronic databases, checking reference lists and citations and retrieving unpublished data. Data of primary studies were extracted and examined by three independent reviewers. The assessment of the methodological quality of included studies was performed using the QUADAS-2 tool. Six studies met the inclusion criteria for this systematic review. The studies presented significant disparities in study design and patient characteristics. Furthermore, high discrepancies in the administration of MEBDT across studies were noted. Therefore, a meta-analysis was not considered appropriate. Sensitivity estimates varied widely across the studies (38-95 %), indicating that the MEBDT is unreliable in detecting OPA. However, the studies emerge with overall high specificity values, ranging from 79 to 100 %. This true negative rate suggests that the MEBDT correctly identifies patients without OPA. This review highlights the need for further research studies assessing the accuracy of the MEBDT in detecting aspiration in patients with tracheostomy, using a standardised and reliable procedure. Outcomes from such studies will update the current level of evidence in relation to the MEBDT and consequently define best clinical practice.