An assessment of a simple clinical technique to estimate pharyngeal collapsibility in people with obstructive sleep apnea

Abstract Study Objectives Quantification of upper airway collapsibility in obstructive sleep apnea (OSA) could help inform targeted therapy decisions. However, current techniques are clinically impractical. The primary aim of this study was to assess if a simple, novel technique could be implemented as part of a continuous positive airway pressure (CPAP) titration study to assess pharyngeal collapsibility. Methods A total of 35 participants (15 female) with OSA (mean ± SD apnea–hypopnea index = 35 ± 19 events/h) were studied. Participants first completed a simple clinical intervention during a routine CPAP titration, where CPAP was transiently turned off from the therapeutic pressure for ≤5 breaths/efforts on ≥5 occasions during stable non-rapid eye movement (non-REM) sleep for quantitative assessment of airflow responses (%peak inspiratory flow [PIF] from preceding 5 breaths). Participants then underwent an overnight physiology study to determine the pharyngeal critical closing pressure (Pcrit) and repeat transient drops to zero CPAP to assess airflow response reproducibility. Results Mean PIF of breaths 3–5 during zero CPAP on the simple clinical intervention versus the physiology night were similar (34 ± 29% vs. 28 ± 30% on therapeutic CPAP, p = 0.2; range 0%–90% vs. 0%–95%). Pcrit was −1.0 ± 2.5 cmH2O (range −6 to 5 cmH2O). Mean PIF during zero CPAP on the simple clinical intervention and the physiology night correlated with Pcrit (r = −0.7 and −0.9, respectively, p < 0.0001). Receiver operating characteristic curve analysis indicated significant diagnostic utility for the simple intervention to predict Pcrit < −2 and < 0 cmH2O (AUC = 0.81 and 0.92), respectively. Conclusions A simple CPAP intervention can successfully discriminate between patients with and without mild to moderately collapsible pharyngeal airways. This scalable approach may help select individuals most likely to respond to non-CPAP therapies.

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Upper airway collapsibility measured using a simple wakefulness test closely relates to the pharyngeal critical closing pressure during sleep in obstructive sleep apnea

SLEEP ◽

10.1093/sleep/zsz080 ◽

2019 ◽

Vol 42 (7) ◽

Cited By ~ 5

Author(s):

Amal M Osman ◽

Jayne C Carberry ◽

Peter G R Burke ◽

Barbara Toson ◽

Ronald R Grunstein ◽

...

Keyword(s):

Obstructive Sleep Apnea ◽

Sleep Apnea ◽

Airway Pressure ◽

Pressure Sensors ◽

Upper Airway ◽

Apnea Hypopnea Index ◽

Pharyngeal Airway ◽

Obstructive Sleep ◽

Airway Collapsibility ◽

Upper Airway Collapsibility

AbstractStudy ObjectivesA collapsible or crowded pharyngeal airway is the main cause of obstructive sleep apnea (OSA). However, quantification of airway collapsibility during sleep (Pcrit) is not clinically feasible. The primary aim of this study was to compare upper airway collapsibility using a simple wakefulness test with Pcrit during sleep.MethodsParticipants with OSA were instrumented with a nasal mask, pneumotachograph and two pressure sensors, one at the choanae (PCHO), the other just above the epiglottis (PEPI). Approximately 60 brief (250 ms) pulses of negative airway pressure (~ –12 cmH2O at the mask) were delivered in early inspiration during wakefulness to measure the upper airway collapsibility index (UACI). Transient reductions in the continuous positive airway pressure (CPAP) holding pressure were then performed during sleep to determine Pcrit. In a subset of participants, the optimal number of replicate trials required to calculate the UACI was assessed.ResultsThe UACI (39 ± 24 mean ± SD; range = 0%–87%) and Pcrit (–0.11 ± 2.5; range: –4 to +5 cmH2O) were quantified in 34 middle-aged people (9 female) with varying OSA severity (apnea–hypopnea index range = 5–92 events/h). The UACI at a mask pressure of approximately –12 cmH2O positively correlated with Pcrit (r = 0.8; p < 0.001) and could be quantified reliably with as few as 10 replicate trials. The UACI performed well at discriminating individuals with subatmospheric Pcrit values [receiver operating characteristic curve analysis area under the curve = 0.9 (0.8–1), p < 0.001].ConclusionsThese findings indicate that a simple wakefulness test may be useful to estimate the extent of upper airway anatomical impairment during sleep in people with OSA to direct targeted non-CPAP therapies for OSA.

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Respiratory control stability and upper airway collapsibility in men and women with obstructive sleep apnea

Journal of Applied Physiology ◽

10.1152/japplphysiol.00410.2004 ◽

2005 ◽

Vol 99 (5) ◽

pp. 2020-2027 ◽

Cited By ~ 88

Author(s):

Amy S. Jordan ◽

Andrew Wellman ◽

Jill K. Edwards ◽

Karen Schory ◽

Louise Dover ◽

...

Keyword(s):

Obstructive Sleep Apnea ◽

Sleep Apnea ◽

Eye Movement ◽

Upper Airway ◽

Apnea Hypopnea Index ◽

Rapid Eye Movement Sleep ◽

Men And Women ◽

Obstructive Sleep ◽

Airway Collapsibility ◽

Upper Airway Collapsibility

Obstructive sleep apnea (OSA) is two to three times more common in men as in women. The mechanisms leading to this difference are currently unclear but could include gender differences in respiratory stability [loop gain (LG)] or upper airway collapsibility [pharyngeal critical closing pressure (Pcrit)]. The aim of this study was to compare LG and Pcrit between men and women with OSA to determine whether the factors contributing to apnea are similar between genders. The first group of 11 men and 11 women were matched for OSA severity (mean ± SE apnea-hypopnea index = 43.8 ± 6.1 and 44.1 ± 6.6 events/h). The second group of 12 men and 12 women were matched for body mass index (BMI; 31.6 ± 1.9 and 31.3 ± 1.8 kg/m2, respectively). All measurements were made during stable supine non-rapid eye movement sleep. LG was determined using a proportional assist ventilator. Pcrit was measured by progressively dropping the continuous positive airway pressure level for three to five breaths until airway collapse. Apnea-hypopnea index-matched women had a higher BMI than men (38.0 ± 2.4 vs. 30.0 ± 1.9 kg/m2; P = 0.03), but LG and Pcrit were similar between men and women (LG: 0.37 ± 0.02 and 0.37 ± 0.02, respectively, P = 0.92; Pcrit: 0.35 ± 0.62 and −0.18 ± 0.87, respectively, P = 0.63). In the BMI-matched subgroup, women had less severe OSA during non-rapid eye movement sleep (30.9 ± 7.4 vs. 52.5 ± 8.1 events/h; P = 0.04) and lower Pcrit (−2.01 ± 0.62 vs. 1.16 ± 0.83 cmH2O; P = 0.005). However, LG was not significantly different between genders (0.38 ± 0.02 vs. 0.33 ± 0.03; P = 0.14). These results suggest that women may be protected from developing OSA by having a less collapsible upper airway for any given degree of obesity.

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