Utility of the modified Volume-Viscosity Swallow Test for bedside screening of dysphagia in critically ill patients

Abstract

Background and aim: Aspiration and dysphagia are frequent in critically ill patients, and evidence of the validity of bedside screening tests is lacking. This study evaluated the modified Volume-Viscosity Swallow Test (mV-VST) as a screening tool for aspiration and dysphagia in intensive care unit patients.

Methods: An observational, prospective longitudinal cohort single-center study included patients older than 18 years old, on mechanical ventilation for at least 48 h, conscious and cooperative. Patients had been admitted in intensive care between March 2016 and August 2019 at a university hospital in Spain. Data from the mV-VST and the flexible endoscopic evaluation of swallowing (FEES) test in extubated and tracheostomized patients were collected; the ROC curve was obtained for each group, and the sensitivity (Se), specificity (Sp), positive (pPV) and negative (nPV) predictive values of mV-VST were calculated and compared with the FEES results. We calculated percentages and 95% confidence intervals (CI) for qualitative variables and means or medians for quantitative variables according to the Shapiro-Wilk test. A univariate analysis identified dysphagia risk factors in each group.

Results: The study included 87 patients: 44 extubated and 43 tracheostomized with similar age, body mass index, Sequential Organ Failure Assessment, Charlson comorbidity index, type and reason for admission. Aspiration with FEES was significantly higher in extubated patients than in tracheostomized patients, 43.2% vs. 23.2%, respectively, p = 0.04. With the mV-VST, aspiration was detected in 54.5% of extubated patients and in 39.5% of tracheostomized patients. In the extubated group, the Se of mV-VST to detect aspiration was 89.5%, Sp was 72%, and nPV was 90%. In the tracheostomized group, Se was 100%, Sp was 78.8%, and nPV was 100%. The ROC curve showed that mV-VST similarly identifies aspiration in extubated and tracheostomized patients.

Conclusions: Dysphagia and aspiration are frequent amongst patients in intensive care after mechanical ventilation. The mV-VST is a valid screening tool to detect aspiration and dysphagia in extubated and tracheostomized patients.

Keywords: Dysphagia; Intensive care unit; Modified Volume-Viscosity Swallow Test; Screening.