Predicting aspiration risk in patients with dysphagia: Evidence from fluoroscopy.

OBJECTIVE: To investigate the potential of timing and displacement measures from fluoroscopic swallow studies for predicting aspiration in dysphagic patients.
METHODS: Timing and displacement variables for a 20-ml liquid bolus were extracted from fluoroscopic swallow studies of 5923 patients reflecting a variety of dysphagia etiologies. Patients were divided into aspirators and non-aspirators, and variables were compared between groups, and to a group of 148 normal control subjects. The relationship of each variable to aspiration was determined. Odds ratios for aspiration were calculated for measures deviating more than two standard deviations from normal. Associations of variables with time of aspiration relative to airway closure were also examined.
RESULTS: Regression analyses revealed that the pharyngeal constriction ratio (PCR) was the measure most predictive of aspiration (74.6%), with percentage of accuracy improving to 76.5% when all measures were considered. Odds Ratios ranging from two times to more than five times were identified for variables deviating more than two standard deviations from normal. Aspiration relative to maximum airway closure, ie, before, during, and after, was also investigated. In the current study, 53% of aspiration events occurred after maximum airway closure, on residue that remained after swallow. Some mechanical impairments appeared specific to timing of aspiration and provide further evidence of the utility of mechanical analysis.
CONCLUSIONS: Results of the review provide substantial support for the value of quantitative assessment of swallow mechanics, and for the role of such data in predicting aspiration risk in dysphagic patients. LEVEL OF EVIDENCE: 3b (retrospective, individual case-control).