Upper-airway collapsibility: measurements and sleep effects.

Area of Science:

• Sleep Medicine
• Respiratory Physiology
• Otolaryngology

Background:

• Obstructive sleep apnea (OSA) involves repetitive pharyngeal collapse during sleep.
• Assessing upper airway collapsibility is crucial for understanding OSA.
• Few studies compare collapsibility between wakefulness and sleep, or between OSA patients and controls.

Purpose of the Study:

• To compare two upper airway collapsibility measurement techniques between normal and apneic subjects.
• To compare collapsibility measurements between wakefulness and sleep states.
• To determine if wakefulness measurements predict sleep collapsibility.

Main Methods:

• Three studies were conducted involving normal subjects and OSA patients.
• Negative pressure pulses (NPPs) assessed collapsibility during wakefulness and sleep.
• Inspiratory resistive loading (IRL) was used to measure collapsibility during sleep in normal subjects.
• Pharyngeal collapsibility was compared between OSA patients and controls during wakefulness using NPPs.

Main Results:

• Wakefulness NPP measurements significantly correlated with sleep NPP measurements (r=0.62, p=0.003).
• Sleep NPP and IRL measurements also showed significant correlation (r=0.53, p=0.04).
• Both methods indicated increased pharyngeal collapsibility during sleep compared to wakefulness.
• OSA patients exhibited significantly greater pharyngeal collapsibility during wakefulness than controls (p=0.017).

Conclusions:

• Upper airway collapsibility measured during wakefulness provides relevant physiological data for sleep.
• These measurements effectively differentiate between individuals with and without OSA.
• The findings support the utility of wakefulness collapsibility assessment in OSA research and potentially clinical practice.