Pulse oximetry does not reliably detect aspiration on videofluoroscopic swallowing study

OBJECTIVE: To examine the reliability of pulse oximetry for identifying aspiration by comparing it with the videofluoroscopic swallowing study (VFSS). DESIGN: Nonrandomized, prospective, double-blind study. SETTING: VFSS laboratory in a teaching hospital. PARTICIPANTS: Sixty patients from among 130 patients with clinically diagnosed dysphagia between September and December 2002. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Simultaneously monitoring the arterial oxygen saturation (Sp o 2 ) by pulse oximetry while patients were performing VFSS. A decrease in Sp o 2 exceeding 3% was considered as significant desaturation. Bolus or portion of bolus passing through the vocal cords and entering the subglottic space was defined as aspiration on VFSS. The results of pulse oximetry and VFSS were compared. RESULTS: No significant correlation existed between desaturation measured by pulse oximetry and aspiration on VFSS (chi 2 test, P =.87). The positive predictive rate of pulse oximetry in detecting aspiration on VFSS was 39.1%, and the negative predictive rate was 59.4%. CONCLUSIONS: Aspiration occurring on VFSS cannot be predicted based on decrease in Sp o 2 in pulse oximetry. The application of pulse oximetry to detect aspiration during regular meals requires further investigation.