Pulse Arterial Tone and Airway Obstruction in Sleep Apnea

Abstract

Objective Determine if continuous pulse arterial tone (PAT) amplitude correlates with upper airway obstructions observed during simultaneous real-time magnetic resonance imaging (RT-MRI) in subjects with Obstructive Sleep Apnea (OSA). Methods A prospective series of 20 subjects diagnosed with mild to severe OSA by polysomnography, Fujita classification, Functional Outcomes of Sleep Questionnaire (FOSQ) and Epworth Sleepiness Score (ESS) underwent continuous RT-MRI during a 90-minute nap without sedation. The upper airway at the mid-saggittal plane was visualized in real time (33 fps) using a sliding window algorithm (RTHawk system). Continuous pulse arterial tone amplitude was simultaneously monitored (Watch-PAT, Itamar Inc, Israel). Results Changes in PAT amplitude were in phase with upper airway narrowing and obstruction from tongue, soft palate, and epiglottis movements. Airway obstructive events occurred coincident to 60% or greater decreases in PAT amplitude. The image sequence associated with each PAT amplitude decrease demonstrated the precise location of the obstruction. Pre-surgical site of airway obstruction and post-surgical cause of persistent obstruction was clearly identified. Conclusions RT-MRI with simultaneous and continuous PAT signal recording during natural sleep is an innovative and improved method for more precisely characterizing airway obstructions in patients with mild to severe OSA. This approach may be valuable for planning surgical treatments, potentially improving the success of these procedures.