What is the Penetration-Aspiration Scale (PAS) and how is it used?

• A. PAS grades the deepest airway invasion observed during swallowing on instrumental study, typically 1 to 8; higher = greater invasion
• B. PAS measures nutritional status
• C. PAS rates patient-reported swallowing difficulty
• D. PAS assesses esophageal peristalsis

Answer: (A)

The Penetration-Aspiration Scale is a standardized way to quantify how severely a swallow breaches the airway. During an instrumental swallow study (like a videofluoroscopic swallow study or FEES), the clinician identifies the deepest level of airway invasion that occurs across the tested swallows and assigns a score on an 8-point scale, with higher numbers reflecting more severe invasion (from no invasion to material passing below the vocal folds and not being cleared). This single score captures the worst airway protection observed and is used to communicate risk, guide management (such as diet modification or swallowing therapy), and monitor changes over time. It’s not about nutritional status, patient-reported swallowing difficulty, or esophageal peristalsis, which is why the other options don’t fit.