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Patterns in pharyngeal airflow associated with sleep-disordered breathing.

ABSTRACT: OBJECTIVE:To establish the feasibility of a noninvasive method to identify pharyngeal airflow characteristics in sleep-disordered breathing. METHODS:Four patients with sleep-disordered breathing who underwent surgery or used positive airway pressure devices and four normal healthy controls were studied. Three-dimensional CT imaging and computational fluid dynamics modeling with standard steady-state numerical formulation were used to characterize pharyngeal airflow behavior in normals and pre-and post-treatment in patients. Dynamic flow simulations using an unsteady approach were performed in one patient. RESULTS:The pre-treatment pharyngeal airway below the minimum cross-sectional area obstruction site showed airflow separation. This generated recirculation airflow regions and enhanced turbulence zones where vortices developed. This interaction induced large fluctuations in airflow variables and increased aerodynamic forces acting on the pharyngeal wall. At post-treatment, for the same volumetric flow rate, airflow field instabilities vanished and airflow characteristics improved. Mean maximum airflow velocity during inspiration reduced from 18.3±5.7 m/s pre-treatment to 6.3±4.5 m/s post-treatment (P=0.002), leading to a reduction in maximum wall shear stress from 4.8±1.7 Pa pre-treatment to 0.9±1.0 Pa post-treatment (P=0.01). The airway resistance improved from 4.3±1.4 Pa/L/min at pre-treatment to 0.7±0.7 Pa/L/min at post-treatment (P=0.004). Post-treatment airflow characteristics were not different from normal controls (all P ? 0.39). CONCLUSION:This study demonstrates that pharyngeal airflow variables may be derived from CT imaging and computational fluid dynamics modeling, resulting in high quality visualizations of airflow characteristics of axial velocity, static pressure, and wall shear stress in sleep-disordered breathing.

SUBMITTER: Powell NB

PROVIDER: S-EPMC5962348 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

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Patterns in pharyngeal airflow associated with sleep-disordered breathing.

Powell Nelson B NB Mihaescu Mihai M Mylavarapu Goutham G Weaver Edward M EM Guilleminault Christian C Gutmark Ephraim E

Sleep medicine 20111028 10

<h4>Objective</h4>To establish the feasibility of a noninvasive method to identify pharyngeal airflow characteristics in sleep-disordered breathing.<h4>Methods</h4>Four patients with sleep-disordered breathing who underwent surgery or used positive airway pressure devices and four normal healthy controls were studied. Three-dimensional CT imaging and computational fluid dynamics modeling with standard steady-state numerical formulation were used to characterize pharyngeal airflow behavior in nor ...[more]

PMID: 22036604

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Project description:ObjectiveTo examine the association between sleep-disordered breathing and stroke outcomes, and determine the contribution of sleep-disordered breathing to outcome disparities in Mexican Americans.MethodsIschemic stroke patients (n = 995), identified from the population-based Brain Attack Surveillance in Corpus Christi Project (2010-2015), were offered participation in a sleep-disordered breathing study including a home sleep apnea test (ApneaLink Plus). Sleep-disordered breathing (respiratory event index ≥10) was determined soon after stroke. Neurologic, functional, cognitive, and quality of life outcomes were assessed at 90 days poststroke. Regression models were used to assess associations between sleep-disordered breathing and outcomes, adjusted for sociodemographics, prestroke function and cognition, health-risk behaviors, stroke severity, and vascular risk factors.ResultsMedian age was 67 years (interquartile range [IQR] = 59-78); 62.1% were Mexican American. Median respiratory event index was 14 (IQR = 6-25); 62.8% had sleep-disordered breathing. Sleep-disordered breathing was associated with worse functional outcome (mean difference in activities of daily living/instrumental activities of daily living score = 0.15, 95% confidence interval [CI] = 0.01-0.28) and cognitive outcome (mean difference in modified Mini-Mental State Examination = -2.66, 95% CI = -4.85 to -0.47) but not neurologic or quality of life outcomes. Sleep-disordered breathing accounted for 9 to 10% of ethnic differences in functional and cognitive outcome and was associated with cognitive outcome more strongly for Mexican Americans (β = -3.97, 95% CI = -6.63 to -1.31) than non-Hispanic whites (β = -0.40, 95% CI = -4.18 to 3.39, p-interaction = 0.15).InterpretationSleep-disordered breathing is associated with worse functional and cognitive function at 90 days poststroke. These outcomes are reasonable endpoints for future trials of sleep-disordered breathing treatment in stroke. If effective, sleep-disordered breathing treatment may somewhat lessen ethnic stroke outcome disparities. ANN NEUROL 2019;86:241-250.

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Patterns in pharyngeal airflow associated with sleep-disordered breathing.

Publications

Patterns in pharyngeal airflow associated with sleep-disordered breathing.

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