Upper Airway Collapsibility Assessed by Negative Expiratory Pressure while Awake is Associated with Upper Airway Anatomy

Abstract

Study Objectives:There is a growing interest to develop a simple method to characterize the mechanisms leading to upper airway collapse in order to guide treatment options in patients with obstructive sleep apnea (OSA). Critical closing pressure (Pcrit) during sleep is able to predict the anatomical component of OSA. However, Pcrit is a laborious method that is only used for research purposes. The application of negative expiratory pressure (NEP) is a simple method to assess upper airway collapsibility that can be easily performed during wakefulness. We hypothesized that NEP will be, similarly to Pcrit, associated with upper airway anatomy assessed by computed tomography (CT) scan. Methods: Patients under investigation for OSA underwent polysomnography, CT of the upper airway, NEP while awake, and Pcrit during sleep. NEP was performed with −5 cm H 2 O in supine position using a nasal mask. Pcrit was measured during sleep induced by low doses of midazolam. Results: Twenty-eight male subjects were studied (age 45 ± 13 y, body mass index 29.4 ± 4.9 kg/m 2 , apnea-hypopnea index (AHI) 30 ± 26, range 2 to 86 events/h). NEP and Pcrit were similarly associated with tongue area (r = 0.646 and r = 0.585), tongue volume (r = 0.565 and r = 0.613) and pharyngeal length (r = 0.580 and r = 0.611), respectively (p < 0.05 for all comparisons). NEP and Pcrit were also significantly correlated with AHI (r = 0.490 and r = 0.531). NEP and Pcrit were significantly higher in patients with severe OSA than the remaining population. Conclusions: NEP is a simple and promising method that is associated with the anatomical component of upper airway collapsibility. NEP may be valuable to select patients for noncontinuous positive airway pressure alternative therapies for OSA.

Loop Gain Predicts the Response to Upper Airway Surgery in Patients With Obstructive Sleep Apnea

“…Crucially, the only anatomical measurement included in our current study was the Mallampati Score, which is inferior to several other routinely utilized anatomical models/scores. 32 This opens up the possibility that baseline LG could be coupled with some simple measure of the patients' anatomical deficiency (ie, obtained using a Friedman score, drug-induced sleep endoscopy findings, or newer techniques measuring upper airway collapsibility during wakefulness 33 or sleep, 34 which could further improve predictive power and reduce unnecessary surgery. The anatomical measure applied to improve the predictive power of the model would ideally be predictive, reproducible, cost-effective, and easy to apply.…”

Personalised medicine in sleep respiratory disorders: focus on obstructive sleep apnoea diagnosis and treatment

“…It has been used to assess upper airway collapsibility in patients with suspected OSA [55]. Application of NEP while awake in the supine position is a simple and promising method that correlates with the anatomical component of upper airway collapsibility [56].…”

Changes in pharyngeal collapsibility and genioglossus reflex responses to negative pressure during the respiratory cycle in obstructive sleep apnoea

“…Negative expiratory pressure is a clinical tool that has been used to evaluate expiratory flow limitation in people with COPD (Koulouris et al 2012). More recently, it has been used in people with OSA to assess changes in breathing and airway collapsibility during early expiration with stimuli of about half the magnitude to that used in the current study (ß−5 cmH 2 O) (Hirata et al 2016). Thus, this requires further investigation using the UACI technique.…”