Static and Dynamic Upper Airway Obstruction in Sleep Apnea

Farré, Ramón; Rigau, Jordi; Montserrat, Josep M.; Buscemi, Lara; Ballester, Eugeni; Navajas, Daniel

doi:10.1164/rccm.200211-1304oc

Cited by 23 publications

(15 citation statements)

References 28 publications

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“…Pcrit is the gold standard for measuring upper airway collapsibility and is defined as the minimal intraluminal airway pressure necessary to keep the collapsible segment open [51]. Therefore, if nasal CPAP is lower than Pcrit, the upper airway is collapsed during inspiration and the patient experiences apnoeas [52].…”

Section: Upper Airway Anatomymentioning

confidence: 99%

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

et al. 2017

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In all fields of medicine, major efforts are currently dedicated to improve the clinical, physiological and therapeutic understanding of disease, and obstructive sleep apnoea (OSA) is no exception. The personalised medicine approach is relevant for OSA, given its complex pathophysiology and variable clinical presentation, the interactions with comorbid conditions and its possible contribution to poor outcomes. Treatment with continuous positive airway pressure (CPAP) is effective, but CPAP is poorly tolerated or not accepted in a considerable proportion of OSA patients. This review summarises the available studies on the physiological phenotypes of upper airway response to obstruction during sleep, and the clinical presentations of OSA ( phenotypes and clusters) with a special focus on our changing attitudes towards approaches to treatment. Such major efforts are likely to change and expand treatment options for OSA beyond the most common current choices (i.e. CPAP, mandibular advancement devices, positional treatment, lifestyle changes or upper airway surgery). More importantly, treatment for OSA may become more effective, being tailored to each patient's need.

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Section: Upper Airway Anatomymentioning

confidence: 99%

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

et al. 2017

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“…However, different mechanisms may be involved in the pathophysiology of apneas with static upper airway obstruction in contrast to hypopneas with dynamic upper airway obstruction. 7 Some patients have a distinct pattern of sleep disordered breathing characterized predominantly by hypopneas with a paucity of apneas. Based on the above and as a result of observations with nocturnal polysomnography (NPSG), we hypothesized that extremely obese patients manifest OSAHS with an unusual preponderance of hypopneas and paucity of apneas, possibly based on a different pathophysiology than that of less obese subjects.…”

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confidence: 99%

High Hypopnea/Apnea Ratio (HAR) in Extreme Obesity

Mathew

Castriotta

2014

Journal of Clinical Sleep Medicine

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Study Objectives:The study was performed to evaluate the hypothesis that the extremely obese manifest sleep disordered breathing with a preponderance of hypopneas and relative paucity of obstructive apneas. Methods: Retrospective review of 90 adults with obstructive sleep apnea-hypopnea syndrome (OSAHS) matched for age and gender, comparing two groups, Group A: body mass index (BMI) < 35, Group B: BMI ≥ 45. Exclusion criteria: age < 18 years, pregnancy, ≥ 5 central apneas/hour, BMI ≥ 35 < 45. Primary Outcome Measure: Hypopnea/apnea ratio (HAR); secondary measures: obstructive apnea-hypopnea index (AHI), obstructive and central apnea indices, hypopnea index (HI), oxygen saturation (SpO 2 ) nadir, end-tidal carbon dioxide tension (PetCO 2 ), and presence of obesity-hypoventilation syndrome (OHS). Statistical methods: t-test for independent samples; Mann-Whitney, linear regression with natural log transformation, and Kruskal-Wallis χ 2 . Descriptive statistics were expressed as interquartile range, median and mean ± standard deviation, p < 0.05 considered signifi cant.Results: Group A (n = 45): age = 50.6 ± 11.5 years, BMI = 28.9 ± 4 kg/m 2 ; Group B (n = 45): age = 47.4 ± 12.7 years, BMI = 54.5 ± 8 kg/m 2 . HAR was signifi cantly higher in Group B (38.8 ± 50.7) than Group A (10.6 ± 16.5), p = 0.0006, as was HI (28.7 ± 28.6 in B vs 12.6 ± 8.4 in A, p = 0.0005) and AHI (35.5 ± 33.8 vs 22 ± 23, p = 0.03), but not apnea index. HAR was signifi cantly higher in Group B regardless of race, gender, or presence of OHS. The BMI was the only signifi cant predictor of HAR (adjusted r 2 = 0.138; p = 0.002) in a linear regression model with natural log transformation of the HAR performed for age, gender, race, BMI, and PetCO 2 . Conclusion: Extremely obese patients manifest OSAHS with a preponderance of hypopneas. Keywords: Obesity, obstructive sleep apnea, hypopnea, obesity-hypoventilation syndrome, gender differences, sleepdisordered breathing, hypopnea/apnea ratio. Citation: Mathew R; Castriotta RJ. High hypopnea/apnea ratio (HAR) in extreme obesity. J Clin Sleep Med 2014;10(4):391-396.http://dx.doi.org/10.5664/jcsm.3612 S C I E N T I F I C I N V E S T I G A T I O N SO besity is one of the major risk factors for obstructive sleep apnea-hypopnea syndrome (OSAHS), 1 which may be defi ned as an apnea-hypopnea index (AHI) ≥ 5 apneas+ hypopneas/hour of sleep, accompanied by symptoms of excessive sleepiness, diffi culty sleeping, or non-refreshing sleep. The prevalence of obesity in the USA has increased by 33% during the last decade, with 40% of men and 55% of women aged 25 years or older being overweight or obese.2 OSAHS has a higher prevalence among obese subjects than among the general population.3 The prevalence of OSAHS (AHI ≥ 15) in obese (body mass index [BMI] ≥ 32-59 kg/m 2 ) adults is 32% 4 and is signifi cantly higher in men with morbid obesity (BMI ≥ 39 kg/ m 2 ) with 40% having an apnea index > 20 apneas/hour. 5 The prevalence of OSAHS among hospitalized patients has been reported to be 60% in the morbidly obese.6 Com...

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“…From a mechanical point of view, the airflow in the upper airway is a process with fluid and structural interactions. The surrounding soft tissues possess not only nonlinear mechanical properties but also the abilities of self-adaptation [6][7][8]. Many mechanical models have been developed in the last few years to study the motion state of the upper airway during apnea.…”

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Control mechanism for the upper airway collapse in patients with obstructive sleep apnea syndrome: a finite element study

Huang

Rong

2013

Sci. China Life Sci.

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Obstructive sleep apnea syndrome (OSAS) is characterized by recurrent collapses of the upper airway, which lead to repetitive transient hypoxia, arousals and finally sleep fragmentation. Both anatomical and neuromuscular factors may play key roles in the pathophysiology of OSAS. The purpose of this paper was to study the control mechanism of OSAS from the mechanical point of view. A three-dimensional finite element model was developed, which not only reconstructed the realistic anatomical structure of the human upper airway, but also included surrounding structures such as the skull, neck, hyoid, cartilage and soft tissues. The respiration process during the normal and apnea states was simulated with the fluid-structure interaction method (FSI) and the computational fluid dynamics method (CFD). The airflow and deformation of the upper airway obtained from the FSI and the CFD method were compared and the results obtained under large negative pressure during an apnea episode were analyzed. The simulation results show that the FSI method is more feasible and effective than the CFD method. The concave configuration of the upper airway may accelerate the collapse of the upper airway in a positive feedback mechanism, which supplies meaningful information for clinical treatment and further research of OSAS.upper airway collapse, sleep apnea, FEM, fluid-structure interaction Citation:Huang R H, Li X P, Rong Q G. Control mechanism for the upper airway collapse in patients with obstructive sleep apnea syndrome: a finite element study. Sci China Life Sci, 2013Sci, , 56: 366-372, doi: 10.1007 Obstructive sleep apnea syndrome (OSAS) is a common sleep-related breathing disorder characterized by repetitive pharyngeal collapse, cessation and reopening of the airflow in the oral and nasal cavity. Two factors may play key roles in the pathophysiology of OSAS: anatomic abnormalities of the upper airway and the weakness or absence of nerve control. Upper airway narrowing is often observed in OSAS patients. To obtain enough airflow during inspiration, more negative pressure is needed at the narrow part of the upper airway. In return, the negative pressure causes further narrowing and eventually the collapse. In addition, required by the needs of speech, swallowing, respiration and other physiological function, a complex nerve control system with more than twenty various muscles plays a role in the upper airway. These groups of muscles interact in a complex fashion, undergoing contraction or relaxation according to the breath state. If the nerve control becomes weak or even absent, the upper airway may collapse under a normal small negative pressure [1][2][3][4][5]. From a mechanical point of view, the airflow in the upper airway is a process with fluid and structural interactions. The surrounding soft tissues possess not only nonlinear mechanical properties but also the abilities of self-adaptation [6][7][8]. Many mechanical models have been developed in the last few years to study the motion state of the upper airway during apnea....

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Static and Dynamic Upper Airway Obstruction in Sleep Apnea

Cited by 23 publications

References 28 publications

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

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

High Hypopnea/Apnea Ratio (HAR) in Extreme Obesity

Control mechanism for the upper airway collapse in patients with obstructive sleep apnea syndrome: a finite element study

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