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Conde SV, Polotsky VY, Joseph V, Kinkead R. On the origins of sleep disordered breathing, cardiorespiratory and metabolic dysfunction: which came first, the chicken or the egg? J Physiol 2023; 601:5509-5525. [PMID: 36988138 PMCID: PMC10539476 DOI: 10.1113/jp284113] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/08/2023] [Indexed: 03/30/2023] Open
Abstract
Sleep disordered breathing (SDB) is a complex, sex specific and highly heterogeneous group of respiratory disorders. Nevertheless, sleep fragmentation and repeated fluctuations of arterial blood gases for several hours per night are at the core of the problem; together, they impose significant stress to the organism with deleterious consequences on physical and mental health. SDB increases the risk of obesity, diabetes, depression and anxiety disorders; however, the same health issues are risk factors for SDB. So, which came first, the chicken or the egg? What causes the appearance of the first significant apnoeic events during sleep? These are important questions because although moderate to severe SDB affects ∼500 million adults globally, we still have a poor understanding of the origins of the disease, and the main treatments (and animal models) focus on the symptoms rather than the cause. Because obesity, metabolic dysfunction and stress-related neurological disorders generally appear progressively, we discuss how the development of these diseases can lead to specific anatomical and non-anatomical traits of SDB in males and females while considering the impacts of sex steroids. In light of the growing evidence indicating that the carotid bodies are important sensors of key metabolic and endocrine signals associated with stress and dysmetabolism, we propose that these organs play a key role in the process.
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Affiliation(s)
- Silvia V. Conde
- NOVA Medical School, Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - Vsevolod Y Polotsky
- Department of Anesthesiology and Critical Care Medicine, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Vincent Joseph
- Département de Pédiatrie, Université Laval & Research Center of the Québec Heart and Lung Institute, Québec, QC. Canada
| | - Richard Kinkead
- Département de Pédiatrie, Université Laval & Research Center of the Québec Heart and Lung Institute, Québec, QC. Canada
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2
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Devenish AN, Nisar T, Criswell A, McCane D, Thao D, Ling KC, Chiu D, Gadhia R. Sex Differences in 90-Day Functional Outcomes for Acute Ischemic Stroke Patients With Obstructive Sleep Apnea. Cureus 2023; 15:e39652. [PMID: 37388591 PMCID: PMC10306317 DOI: 10.7759/cureus.39652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2023] [Indexed: 07/01/2023] Open
Abstract
Background Obstructive sleep apnea (OSA) is characterized by repeated episodes of either full or partial obstruction of the upper airway. OSA is an independent risk factor for acute ischemic stroke (AIS) and a contributor to other key risk factors. OSA may damage endothelial and brain tissues and worsen outcomes following AIS. We aimed to evaluate the impact of sex differences on 90-day functional outcomes following AIS in an OSA population, as measured by the modified Rankin Scale (mRS) score. Methodology We performed a retrospective study of patients with OSA and AIS from the Houston Methodist Hospital Outcomes-Based Prospective Endpoints in Stroke (HOPES) Registry from 2016 to 2022. Patients with charts that noted a diagnosis of OSA before AIS or within the 90 days following AIS were included. A multivariable logistic regression model was constructed adjusting for demographics, first admit National Institutes of Health Stroke Scale (NIHSS), and comorbidities on the binary outcome. The odds ratios (ORs) and 95% confidence intervals (CIs) were reported, providing likelihood estimates of a shift to higher mRS for a given comparison between females (reference category) and males. Statistical significance was defined as two-tailed p-values <0.05 for all tests. Results From the HOPES registry, 291 females and 449 males were found to have OSA. Males had a higher proportion of comorbid conditions such as atrial fibrillation (15% vs. 9%, p = 0.014) and intracranial hemorrhage compared to females (6% vs. 2%, p = 0.020). The multivariate logistic regression model showed that males were at two times higher risk for developing poor functional outcomes at 90 days (OR = 2.35, 95% CI = 1.06-5.19), p < 0.001). Conclusions Males were found to have two times higher risk for developing poor functional outcomes at 90 days. This may be due to more severe oxygen desaturation, increased susceptibility to oxidative stress, and greater frequency of full airway obstruction in males. Greater emphasis on early diagnosis and treatment of OSA may be necessary to reduce the disproportionate incidence of poor functional outcomes, particularly among apneic male stroke survivors.
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Affiliation(s)
| | - Tariq Nisar
- Neurology, Houston Methodist Hospital, Houston, USA
| | - Amber Criswell
- Neurology, Houston Methodist Neurological Institute, Houston, USA
| | - David McCane
- Neurology, Houston Methodist Hospital, Houston, USA
| | - Dinh Thao
- Neurology, Houston Methodist Neurological Institute, Houston, USA
| | | | - David Chiu
- Neurology, Houston Methodist Hospital, Houston, USA
| | - Rajan Gadhia
- Neurology, Houston Methodist Neurological Institute, Houston, USA
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3
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Javaheri S, Rapoport DM, Schwartz AR. Distinguishing central from obstructive hypopneas on a clinical polysomnogram. J Clin Sleep Med 2023; 19:823-834. [PMID: 36661093 PMCID: PMC10071374 DOI: 10.5664/jcsm.10420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/22/2022] [Accepted: 11/22/2022] [Indexed: 01/21/2023]
Abstract
Among sleep-related disordered breathing events, hypopneas are the most frequent. Like obstructive and central apneas, hypopneas may be obstructive or central (reduced drive) in origin. Nevertheless, unlike apneas, categorizing hypopneas as either "obstructive" or "central" is often difficult or ambiguous. It has been suggested that hypopneas could be categorized as obstructive when associated with snoring, inspiratory flow limitation, or paradoxical thoraco-abdominal excursions. This approach, however, has not been extensively tested and misclassification of hypopneas is unavoidable. Yet, much rides on the accurate distinction of these events to guide therapy with medical devices or pharmacological therapy in each patient. Additionally, accurate hypopnea classification is critical for design of clinical trials, because therapeutic responses differ depending on the subtype of hypopnea. Correctly classifying hypopneas can also allay concerns about obtaining coverage for therapies that specifically target either central or obstructive sleep-disordered breathing events. The present paper expands on the current criteria for differentiating obstructive from central hypopneas and provides illustrative tracings that can help classify these events. CITATION Javaheri S, Rapoport DM, Schwartz AR. Distinguishing central from obstructive hypopneas on a clinical polysomnogram. J Clin Sleep Med. 2023;19(4):823-834.
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Affiliation(s)
- Shahrokh Javaheri
- Division of Pulmonary and Sleep, Bethesda North Hospital, Cincinnati, Ohio
| | - David M. Rapoport
- Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Alan R. Schwartz
- University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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Zhang Z, Sowho M, Otvos T, Sperandio LS, East J, Sgambati F, Schwartz A, Schneider H. A comparison of automated and manual sleep staging and respiratory event recognition in a portable sleep diagnostic device with in-lab sleep study. J Clin Sleep Med 2021; 16:563-573. [PMID: 32022670 PMCID: PMC7161441 DOI: 10.5664/jcsm.8278] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
STUDY OBJECTIVES The objectives were to develop and validate an algorithm for editing WatchPAT scoring and assess the accuracy in an unselected clinical population as well as age and sex substrata. METHODS Two hundred sixty-two participants were enrolled to undergo WatchPAT simultaneously with in-lab polysomnography (PSG) recordings for developing (n = 30), optimizing (n = 62), and validating (n = 170) an algorithm to review and edit respiratory events and sleep architecture of WatchPAT recordings, which was based on visual inspection of WatchPAT signals. Apnea-hypopnea index (AHI) and sleep indices were compared with PSG-derived and automated WatchPAT indices. RESULTS Although estimation of total sleep time (TST) was comparable between automated and manual algorithm, estimation of rapid eye movement (REM) sleep time was markedly improved with manual editing from 0.48, 23.0 min (-43.9 to 89.8) to 0.64, 18.3 min (-32.6 to 69.1) (correlation with PSG, mean difference [reference range] from PSG, respectively). Manual scoring also improved correlation and agreement with PSG AHI from 0.65, 2.5 events/h (-24.0 to 28.9) to 0.81, -4.5 events/h (-22.5 to 13.6) as well as concordance for categorical agreement of sleep-disordered breathing severity and concordance for detecting severe REM-related sleep-disordered breathing. Interscorer reliabilities were excellent for TST and AHI, while good for REM sleep time. The automated algorithm performed better in younger than in older patients, while performed similarly between men and women with respect to concordance statistics. The manual algorithm markedly improved concordances more in older patients and women than in their counterparts. CONCLUSIONS Our manual editing algorithm improves correlation and agreement with PSG-derived sleep and breathing indices. Sex and age influence the accuracy of automated analysis and the performance of manual editing on AHI concordance.
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Affiliation(s)
- Zhigang Zhang
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland.,Department of Geriatrics, Peking University First Hospital, Beijing, China
| | - Mudiaga Sowho
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Tamas Otvos
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Larissa Sanglard Sperandio
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Joshua East
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Frank Sgambati
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Alan Schwartz
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Hartmut Schneider
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
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Sasai-Sakuma T, Kayaba M, Inoue Y, Nakayama H. Prevalence, clinical symptoms and polysomnographic findings of REM-related sleep disordered breathing in Japanese population. Sleep Med 2021; 80:52-56. [PMID: 33556778 DOI: 10.1016/j.sleep.2021.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/09/2020] [Accepted: 01/04/2021] [Indexed: 10/22/2022]
Abstract
BACKGROUND Rapid eye movement sleep -predominant sleep-disordered breathing (REM-SDB) is a condition in which sleep apneas or hypopneas predominantly occur during REM sleep. This study aimed to investigate the prevalence, clinical findings including daytime sleepiness or comorbid cardio-metabolic diseases, and detailed polysomnographic features of REM-SDB in Japanese population. METHODS Total of 1458 patients diagnosed as SDB were selected for this study. Prevalence of REM-SDB was estimated in the groups of mild, moderate and severe SDB. Polysomnographic findings, daytime sleepiness self-measured with Epworth Sleepiness Scale (ESS) and history of comorbid cardio-metabolic diseases were obtained and compared between the groups with REM-SDB and non-stage specific SDB. RESULTS Prevalence of REM-SDB according to the criteria #2 was 22.1% in total SDB subjects, 46,1% in mild SDB and 18.9% in moderate SDB. None was found in severe SDB. Patients with REM-SDB showed milder SDB, higher BMI and higher female predominance than those with non-stage specific SDB. They also showed lower arousal index, respiratory arousal index per total AHI, percentage of N1 sleep, total AHI, ODI, and higher sleep efficiency. Meanwhile, maximum event durations of obstructive apnea and hypopnea were significantly longer, and the nadir SpO2 was lower in REM-SDB. The ESS score and percentages of comorbid cardio-metabolic diseases were roughly equivalent between REM-SDB and non-stage specific SDB. CONCLUSION REM-SDB was associated with high obesity, female gender, and mild severity of SDB. They showed daytime sleepiness and comorbid cardio-metabolic diseases quite equally to patients with non-stage specific SDB in spite of their lower AHI and better sleep quality.
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Affiliation(s)
- Taeko Sasai-Sakuma
- Teikyo University, Faculty of Medical Technique, Department of Clinical Laboratory Science, Japan; Tokyo Medical University, Department of Somnology, Japan; Japan Somnology Center, Neuropsychiatric Research Institute, Japan.
| | - Momoko Kayaba
- Tokyo Medical University, Department of Somnology, Japan; Japan Somnology Center, Neuropsychiatric Research Institute, Japan
| | - Yuichi Inoue
- Tokyo Medical University, Department of Somnology, Japan; Japan Somnology Center, Neuropsychiatric Research Institute, Japan
| | - Hideaki Nakayama
- Tokyo Medical University, Department of Somnology, Japan; Japan Somnology Center, Neuropsychiatric Research Institute, Japan
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6
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Wang X, Li W, Zhou J, Wei Z, Li X, Xu J, Zhang F, Wang W. Smoking and sleep apnea duration mediated the sex difference in daytime sleepiness in OSA patients. Sleep Breath 2020; 25:289-297. [PMID: 32529520 DOI: 10.1007/s11325-020-02109-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 04/23/2020] [Accepted: 05/15/2020] [Indexed: 01/19/2023]
Abstract
PURPOSE Daytime sleepiness is a common symptom of obstructive sleep apnea (OSA) and is more common in men, but the underlying mechanism remains unclear. The aim of this study was to assess whether or not sex differences in daytime sleepiness persisted after controlling for age and OSA severity and to explore the factors contributing to daytime sleepiness in patients with OSA. METHODS A total of 104 pairs of patients with OSA, matched by age and apnea-hypopnea index (AHI), were enrolled in this retrospective study. Demographic data were collected; daytime sleepiness was measured by the Epworth Sleepiness Scale (ESS); and polysomnography (PSG) was performed on each participant. These measurements were compared between sexes, and the factors affecting daytime sleepiness were explored with correlation and multivariate linear regression analyses. RESULTS Men had significantly higher ESS scores (p = 0.021) than women. Regarding demographics, BMI, neck/height ratio, and proportion of habitual smoking and alcohol intake were significantly higher in men. Regarding PSG findings, men had more rapid eye movement sleep, a longer mean apnea-hypopnea duration, and a longer mean apnea duration (MAD). Regression analysis showed that two sex-associated variables, habitual smoking (β = 0.189, p = 0.006) and MAD (β = 0.154, p = 0.024), had the strongest association with ESS scores. Further analysis revealed that MAD was significantly influenced by apnea index (β = 0.306, p < 0.001) and sex (β = - 0.193, p = 0.003). CONCLUSION The sex difference in daytime sleepiness persists in patients with OSA, even after matching AHI and age. The difference is mediated by sex-specific smoking habits and sex differences in apnea duration.
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Affiliation(s)
- Xingjian Wang
- Institute of Respiratory and Critical Care Medicine, The First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Wenyang Li
- Institute of Respiratory and Critical Care Medicine, The First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Jiawei Zhou
- Institute of Respiratory and Critical Care Medicine, The First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Zhijing Wei
- Institute of Respiratory and Critical Care Medicine, The First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Xiaomeng Li
- Institute of Respiratory and Critical Care Medicine, The First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Jiahuan Xu
- Department of Respiratory Medicine, Zhejiang Hospital, Hangzhou, Zhejiang, China
| | - Fang Zhang
- Institute of Respiratory and Critical Care Medicine, The First Hospital of China Medical University, Shenyang, Liaoning, China
| | - Wei Wang
- Institute of Respiratory and Critical Care Medicine, The First Hospital of China Medical University, Shenyang, Liaoning, China.
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7
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Inoshita A, Kasai T, Matsuoka R, Sata N, Shiroshita N, Kawana F, Kato M, Ikeda K. Age-stratified sex differences in polysomnographic findings and pharyngeal morphology among children with obstructive sleep apnea. J Thorac Dis 2018; 10:6702-6710. [PMID: 30746215 DOI: 10.21037/jtd.2018.11.09] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Background Childhood obstructive sleep apnea (OSA) has important implications for growth, learning, behavior, cognition and cardiovascular health as well as snoring and OSA in adulthood. In this study, we elucidated the sex differences in polysomnographic (PSG) findings and pharyngeal radiographic data in pediatric OSA patients. Methods Sixty three children (age between 3 and 15 years old) with OSA [defined as apnea-hypopnea index (AHI) ≥1/h by polysomnography] were enrolled. Lateral neck radiographs were obtained from the patients. All subjects were separated by age: pre-adolescent group (3-8 years old) and adolescent group (9-15 years old). Results Overall, 45 patients in the pre-adolescent group (33 boys and 12 girls) and 18 patients in the adolescent group (10 boys and 8 girls) were enrolled, and sex differences were compared in each group. We found sex differences in craniofacial features and severity of OSA in the adolescent group, in which girls with OSA had more upper airway space, in addition to lower AHI, lower 3% oxygen desaturation index (ODI), higher minimum SO2 and better sleep efficiency than the boys. Conclusions The present study found revealed sex differences in pediatric OSA patients in the adolescent group. Girls in the adolescent group had more upper airway space in addition to lower AHI, lower 3% ODI, higher minimum SO2 and better sleep efficiency than boys.
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Affiliation(s)
- Ayako Inoshita
- Department of Otorhinolaryngology, Head and Neck Surgery, Juntendo University School of Medicine, Tokyo, Japan.,Sleep and Sleep-Disordered Breathing Center, Juntendo University Hospital, Tokyo, Japan
| | - Takatoshi Kasai
- Sleep and Sleep-Disordered Breathing Center, Juntendo University Hospital, Tokyo, Japan.,Cardiovascular Respiratory Sleep Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Department of Cardiovascular Medicine, Juntendo University School of Medicine, Tokyo, Japan
| | - Rina Matsuoka
- Department of Otorhinolaryngology, Head and Neck Surgery, Juntendo University School of Medicine, Tokyo, Japan
| | - Naoko Sata
- Department of Otorhinolaryngology, Head and Neck Surgery, Juntendo University School of Medicine, Tokyo, Japan.,Sleep and Sleep-Disordered Breathing Center, Juntendo University Hospital, Tokyo, Japan
| | - Nanako Shiroshita
- Cardiovascular Respiratory Sleep Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Fusae Kawana
- Cardiovascular Respiratory Sleep Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Mitsue Kato
- Cardiovascular Respiratory Sleep Medicine, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Katsuhisa Ikeda
- Department of Otorhinolaryngology, Head and Neck Surgery, Juntendo University School of Medicine, Tokyo, Japan
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Fleury Curado T, Oliven A, Sennes LU, Polotsky VY, Eisele D, Schwartz AR. Neurostimulation Treatment of OSA. Chest 2018; 154:1435-1447. [PMID: 30222959 DOI: 10.1016/j.chest.2018.08.1070] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/02/2018] [Accepted: 08/30/2018] [Indexed: 01/04/2023] Open
Abstract
Over the past 30 years, hypoglossal nerve stimulation has moved through a development pathway to become a viable treatment modality for patients with OSA. Initial pilot studies in animals and humans laid the conceptual foundation for this approach, leading to the development of fully implantable stimulating systems for therapeutic purposes. These devices were then shown to be both safe and efficacious in feasibility studies. One such closed-loop stimulating device was found to be effective in treating a limited spectrum of apneic patients and is currently approved by the US Food and Drug Administration for this purpose. Another open-loop stimulating system is currently being rigorously tested in a pivotal trial. Collectively, clinical trials of hypoglossal nerve stimulating systems have yielded important insights that can help optimize therapeutic responses to hypoglossal nerve stimulation. These insights include specific patient selection criteria and methods for delivering stimulation to specific portions of the hypoglossal nerve and/or genioglossus muscle. New approaches for activating efferent and afferent motor pathways are currently in early-stage laboratory development and hold some long-term promise as a novel therapy.
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Affiliation(s)
- Thomaz Fleury Curado
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD; Department of Otorhinolaryngology, University of São Paulo Medical School, São Paulo, Brazil.
| | - Arie Oliven
- Department of Medicine, Bnai Zion Medical Center, Technion, Haifa, Israel
| | - Luiz U Sennes
- Department of Otorhinolaryngology, University of São Paulo Medical School, São Paulo, Brazil
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD
| | - David Eisele
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University, Baltimore, MD
| | - Alan R Schwartz
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD
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Abstract
Leptin is a peptide hormone produced mainly in white adipose tissue. It is known to regulate energy homeostasis, inflammation, metabolism, and sympathetic nerve activity. Increasing evidence suggests it has a role in ventilatory function and upper airway obstruction. Leptin levels correlate positively with measurements of adiposity and can potentially provide important insights into the pathophysiology of diseases associated with obesity. Obesity is a strong risk factor for obstructive sleep apnea, a disease characterized by periodic upper airway occlusion during sleep. The neuromuscular activity that maintains upper airway patency during sleep and the anatomy of upper airway are key factors involved in its pathogenesis. Experimental studies using animal models of a low leptin state such as leptin deficiency have shown that leptin regulates sleep architecture, upper airway patency, ventilatory function, and hypercapnic ventilatory response. However, findings from human studies do not consistently support the data from the animal models. The effect of leptin on the pathophysiology of obstructive sleep apnea is being investigated, but the results of studies have been confounded by leptin's diurnal variation and the short-term effects of feeding, adiposity, age, and sex. Improved study design and methods of assessing functional leptin levels, specifically their central versus peripheral effects, will improve understanding of the role of leptin in sleep apnea.
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Baum DM, Saussereau M, Jeton F, Planes C, Voituron N, Cardot P, Fiamma MN, Bodineau L. Effect of Gender on Chronic Intermittent Hypoxic Fosb Expression in Cardiorespiratory-Related Brain Structures in Mice. Front Physiol 2018; 9:788. [PMID: 29988603 PMCID: PMC6026892 DOI: 10.3389/fphys.2018.00788] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 06/06/2018] [Indexed: 12/19/2022] Open
Abstract
We aimed to delineate sex-based differences in neuroplasticity that may be associated with previously reported sex-based differences in physiological alterations caused by repetitive succession of hypoxemia-reoxygenation encountered during obstructive sleep apnea (OSA). We examined long-term changes in the activity of brainstem and diencephalic cardiorespiratory neuronal populations induced by chronic intermittent hypoxia (CIH) in male and female mice by analyzing Fosb expression. Whereas the overall baseline and CIH-induced Fosb expression in females was higher than in males, possibly reflecting different neuroplastic dynamics, in contrast, structures responded to CIH by Fosb upregulation in males only. There was a sex-based difference at the level of the rostral ventrolateral reticular nucleus of the medulla, with an increase in the number of FOSB/ΔFOSB-positive cells induced by CIH in males but not females. This structure contains neurons that generate the sympathetic tone and which are involved in CIH-induced sustained hypertension during waking hours. We suggest that the sex-based difference in neuroplasticity of this structure contributes to the reported sex-based difference in CIH-induced hypertension. Moreover, we highlighted a sex-based dimorphic phenomenon in serotoninergic systems induced by CIH, with increased serotoninergic immunoreactivity in the hypoglossal nucleus and a decreased number of serotoninergic cells in the dorsal raphe nucleus in male but not female mice. We suggest that this dimorphism in the neuroplasticity of serotoninergic systems predisposes males to a greater alteration of neuronal control of the upper respiratory tract associated with the greater collapsibility of upper airways described in male OSA subjects.
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Affiliation(s)
- David M Baum
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, UMR-S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
| | - Maud Saussereau
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, UMR-S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
| | - Florine Jeton
- Sorbonne Paris Cité, Université Paris 13, EA2363 Hypoxie et Poumon, Bobigny, France
| | - Carole Planes
- Sorbonne Paris Cité, Université Paris 13, EA2363 Hypoxie et Poumon, Bobigny, France
| | - Nicolas Voituron
- Sorbonne Paris Cité, Université Paris 13, EA2363 Hypoxie et Poumon, Bobigny, France
| | - Philippe Cardot
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, UMR-S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
| | - Marie-Noëlle Fiamma
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, UMR-S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
| | - Laurence Bodineau
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, UMR-S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
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12
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Gouveris H, Bahr K, Jahn C, Matthias C, Simon P. The Apnea-Hypopnea Index Underestimates Systemic Inflammation in Women with Sleep-Disordered Breathing. J Womens Health (Larchmt) 2018; 27:920-926. [PMID: 29630436 DOI: 10.1089/jwh.2017.6819] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Evidence suggests that sleep-related respiratory and related metabolic compromise may vary between females and males with sleep-disordered breathing (SDB). Our purpose was to elucidate possible gender differences in sleep-associated respiratory and inflammatory parameters in patients with SDB. MATERIALS AND METHODS A consecutive number of SDB patients (46 females and 167 males) who underwent polysomnography were retrospectively reviewed. Fibrinogen and C-reactive protein (CRP) concentration, apnea index (ApnI), hypopnea index (HypI), apnea-hypopnea index (AHI), average and minimal SpO2, duration of snoring, age, and body mass index (BMI) were compared between sexes. Spearman's ρ correlation coefficients between parameters were also calculated. RESULTS ApnI and AHI were significantly higher in males. Correlation analysis revealed striking gender differences: only in females, CRP concentration was highly correlated with snoring duration (r = 0.4393), BMI (r = 0.7147), minimal SpO2 (r = -0.4357), and average SpO2 (r = -0.4547); in females, HypI was more strongly correlated with AHI (r = 0.8778), average SpO2 (r = -0.5765), minimal SpO2 (r = -0.5817), and fibrinogen concentration (r = 0.4614) than in males (r = 0.4373; -0.3295; -0.2969; and 0.0887, respectively); in females, age had a much more pronounced effect on ApnI, HypI, AHI, average oxygen saturation (SaO2), minimal SaO2, snoring duration, and CRP and fibrinogen concentration. CONCLUSIONS Respiratory compromise in females with SDB is more strongly associated with systemic inflammation than in males with SDB. Although females display a pathological AHI less frequently than males, they reach quite similar pathological SaO2, CRP, and fibrinogen values. Therefore, AHI may underestimate the pathophysiological systemic effects of SDB in females.
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Affiliation(s)
- Haralampos Gouveris
- 1 Sleep Medicine Centre and Department of Otorhinolaryngology, Medical Centre of the University of Mainz , Mainz, Germany
| | - Katharina Bahr
- 1 Sleep Medicine Centre and Department of Otorhinolaryngology, Medical Centre of the University of Mainz , Mainz, Germany
| | - Christoph Jahn
- 1 Sleep Medicine Centre and Department of Otorhinolaryngology, Medical Centre of the University of Mainz , Mainz, Germany
| | - Christoph Matthias
- 1 Sleep Medicine Centre and Department of Otorhinolaryngology, Medical Centre of the University of Mainz , Mainz, Germany
| | - Perikles Simon
- 2 Department of Sports Medicine, Rehabilitation and Disease Prevention, University of Mainz , Mainz, Germany
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Guzman MA, Sgambati FP, Pho H, Arias RS, Hawks EM, Wolfe EM, Ötvös T, Rosenberg R, Dakheel R, Schneider H, Kirkness JP, Smith PL, Schwartz AR. The Efficacy of Low-Level Continuous Positive Airway Pressure for the Treatment of Snoring. J Clin Sleep Med 2017; 13:703-711. [PMID: 28356182 DOI: 10.5664/jcsm.6588] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 01/24/2017] [Indexed: 12/29/2022]
Abstract
STUDY OBJECTIVES To assess effects of low-level continuous positive airway pressure (CPAP) on snoring in habitual snorers without obstructive sleep apnea (OSA). METHODS A multicenter prospective in-laboratory reversal crossover intervention trial was conducted between September 2013 and August 2014. Habitual snorers were included if they snored (inspiratory sound pressure level ≥ 40 dBA) for ≥ 30% all sleep breaths on a baseline sleep study (Night 1), and if significant OSA and daytime somnolence were absent. Included participants then underwent a CPAP titration study at 2, 4, or 6 cm H2O (Night 2) to examine snoring responses to step-increases in nasal pressure, a treatment night at optimal pressure (Night 3), followed by baseline night (Night 4). At each pressure, snoring intensity was measured on each breath. Snoring frequency was quantified as a percentage of sleep breaths at thresholds of 40, 45, 50, and 55 dBA. Sleep architecture and OSA severity were characterized using standard measurements. RESULTS On baseline sleep studies, participants demonstrated snoring at ≥ 40 dBA on 53 ± 3% and ≥ 45 dBA on 35 ± 4% of breaths. Snoring frequency decreased progressively as nasal pressure increased from 0 to 4 cm H2O at each threshold, and plateaued thereafter. CPAP decreased snoring frequency by 67% and 85% at 40 and 45 dBA, respectively. Intervention did not alter sleep architecture and sleep apnea decreased minimally. CONCLUSIONS Low-level CPAP below the range required to treat OSA diminished nocturnal snoring, and produced uniform reduction in nightly noise production below the World Health Organization's limit of 45 dBA. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, identifier: NCT01949584.
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Affiliation(s)
- Michelle A Guzman
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | - Francis P Sgambati
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | - Huy Pho
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | - Rafael S Arias
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | - Erin M Hawks
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | - Erica M Wolfe
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | - Tamás Ötvös
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | | | - Riad Dakheel
- Doctors Community Hospital Sleep Center, Lanham, Maryland
| | - Hartmut Schneider
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | - Jason P Kirkness
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | - Philip L Smith
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
| | - Alan R Schwartz
- Johns Hopkins Sleep Disorders Center, Center for Interdisciplinary Sleep Research and Education, Baltimore, Maryland
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14
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Azarbarzin A, Sands SA, Taranto-Montemurro L, Oliveira Marques MD, Genta PR, Edwards BA, Butler J, White DP, Wellman A. Estimation of Pharyngeal Collapsibility During Sleep by Peak Inspiratory Airflow. Sleep 2017; 40:2666705. [PMID: 28364460 PMCID: PMC6084748 DOI: 10.1093/sleep/zsw005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Objectives Pharyngeal critical closing pressure (Pcrit) or collapsibility is a major determinant of obstructive sleep apnea (OSA) and may be used to predict the success/failure of non-continuous positive airway pressure (CPAP) therapies. Since its assessment involves overnight manipulation of CPAP, we sought to validate the peak inspiratory flow during natural sleep (without CPAP) as a simple surrogate measurement of collapsibility. Methods Fourteen patients with OSA attended overnight polysomnography with pneumotachograph airflow. The middle third of the night (non-rapid eye movement sleep [NREM]) was dedicated to assessing Pcrit in passive and active states via abrupt and gradual CPAP pressure drops, respectively. Pcrit is the extrapolated CPAP pressure at which flow is zero. Peak and mid-inspiratory flow off CPAP was obtained from all breaths during sleep (excluding arousal) and compared with Pcrit. Results Active Pcrit, measured during NREM sleep, was strongly correlated with both peak and mid-inspiratory flow during NREM sleep (r = -0.71, p < .005 and r = -0.64, p < .05, respectively), indicating that active pharyngeal collapsibility can be reliably estimated from simple airflow measurements during polysomnography. However, there was no significant relationship between passive Pcrit, measured during NREM sleep, and peak or mid-inspiratory flow obtained from NREM sleep. Flow measurements during REM sleep were not significantly associated with active or passive Pcrit. Conclusions Our study demonstrates the feasibility of estimating active Pcrit using flow measurements in patients with OSA. This method may enable clinicians to estimate pharyngeal collapsibility without sophisticated equipment and potentially aid in the selection of patients for non- positive airway pressure therapies.
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Affiliation(s)
- Ali Azarbarzin
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Scott A Sands
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
- Department of Allergy Immunology and Respiratory Medicine and Central Clinical School, The Alfred and Monash University, Melbourne, Australia
| | - Luigi Taranto-Montemurro
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Melania D Oliveira Marques
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
- Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas, University of São Paulo School of Medicine, São Paulo, Brazil
| | - Pedro R Genta
- Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas, University of São Paulo School of Medicine, São Paulo, Brazil
| | - Bradley A Edwards
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
- Sleep and Circadian Medicine Laboratory, Department of Physiology Monash University, Melbourne, Victoria, Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - James Butler
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - David P White
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Andrew Wellman
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
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15
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O'Halloran KD, Lewis P, McDonald F. Sex, stress and sleep apnoea: Decreased susceptibility to upper airway muscle dysfunction following intermittent hypoxia in females. Respir Physiol Neurobiol 2016; 245:76-82. [PMID: 27884793 DOI: 10.1016/j.resp.2016.11.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 11/19/2016] [Accepted: 11/20/2016] [Indexed: 12/21/2022]
Abstract
Obstructive sleep apnoea syndrome (OSAS) is a devastating respiratory control disorder more common in men than women. The reasons for the sex difference in prevalence are multifactorial, but are partly attributable to protective effects of oestrogen. Indeed, OSAS prevalence increases in post-menopausal women. OSAS is characterized by repeated occlusions of the pharyngeal airway during sleep. Dysfunction of the upper airway muscles controlling airway calibre and collapsibility is implicated in the pathophysiology of OSAS, and sex differences in the neuro-mechanical control of upper airway patency are described. It is widely recognized that chronic intermittent hypoxia (CIH), a cardinal feature of OSAS due to recurrent apnoea, drives many of the morbid consequences characteristic of the disorder. In rodents, exposure to CIH-related redox stress causes upper airway muscle weakness and fatigue, associated with mitochondrial dysfunction. Of interest, in adults, there is female resilience to CIH-induced muscle dysfunction. Conversely, exposure to CIH in early life, results in upper airway muscle weakness equivalent between the two sexes at 3 and 6 weeks of age. Ovariectomy exacerbates the deleterious effects of exposure to CIH in adult female upper airway muscle, an effect partially restored by oestrogen replacement therapy. Intriguingly, female advantage intrinsic to upper airway muscle exists with evidence of substantially greater loss of performance in male muscle during acute exposure to severe hypoxic stress. Sex differences in upper airway muscle physiology may have relevance to human OSAS. The oestrogen-oestrogen receptor α axis represents a potential therapeutic target in OSAS, particularly in post-menopausal women.
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Affiliation(s)
- Ken D O'Halloran
- Department of Physiology, University College Cork, Cork, Ireland.
| | - Philip Lewis
- Department of Physiology, University College Cork, Cork, Ireland; Institute and Policlinic for Occupational Medicine, Environmental Medicine and Preventative Research, University of Cologne, Germany
| | - Fiona McDonald
- Physiology, School of Medicine, University College Dublin, Dublin, Ireland; School of Clinical Sciences, Bristol University, Bristol, United Kingdom
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16
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Hirata RP, Schorr F, Kayamori F, Moriya HT, Romano S, Insalaco G, Gebrim EM, de Oliveira LVF, Genta PR, Lorenzi-Filho G. Upper Airway Collapsibility Assessed by Negative Expiratory Pressure while Awake is Associated with Upper Airway Anatomy. J Clin Sleep Med 2016; 12:1339-1346. [PMID: 27448414 DOI: 10.5664/jcsm.6184] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 06/06/2016] [Indexed: 12/19/2022]
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 H2O 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/m2, 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.
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Affiliation(s)
- Raquel P Hirata
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Fabiola Schorr
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Fabiane Kayamori
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | | | - Salvatore Romano
- Institute of Biomedicine and Molecular Immunology A. Monroy, Italian National Research Council, Palermo, Italy
| | - Giuseppe Insalaco
- Institute of Biomedicine and Molecular Immunology A. Monroy, Italian National Research Council, Palermo, Italy
| | - Eloisa M Gebrim
- Radiology Institute (InRad), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | | | - Pedro R Genta
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
| | - Geraldo Lorenzi-Filho
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil
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17
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Llanos OL, Galiatsatos P, Guzmán-Vélez E, Patil SP, Smith PL, Magnuson T, Schweitzer M, Steele K, Polotsky VY, Schwartz AR. Pharyngeal collapsibility during sleep is elevated in insulin-resistant females with morbid obesity. Eur Respir J 2016; 47:1718-26. [PMID: 27103392 DOI: 10.1183/13993003.00918-2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 01/31/2016] [Indexed: 12/21/2022]
Abstract
Insulin resistance is associated with sleep apnoea, leading us to hypothesise that it is also associated with elevations in pharyngeal collapsibility, even in the absence of sleep apnoea.90 bariatric patients were characterised for sleep apnoea, pharyngeal collapsibility and insulin resistance. Patients with a respiratory disturbance index (RDI) >10 events·h(-1), diabetes mellitus, tonsillar hypertrophy and pulmonary disease were excluded. The remaining 14 females underwent collapsibility measurements (passive critical pressure, Pcritp ) during non-rapid eye movement sleep. The homeostasis model assessment (HOMA) index, a measure of insulin resistance, was derived from measurements of fasting glucose and insulin levels, and compared to Pcritp Groups with high Pcritp compared to low Pcritp did not differ in age, body mass index or RDI. HOMA and insulin were elevated in the high Pcritp group compared to the low Pcritp group (p<0.02). Pcritp correlated with HOMA (Spearman's ρ=0.565, 95% CI 0.104-0.862; p=0.035) and insulin (Spearman's ρ=0.609 95% CI 0.196-0.835; p=0.021).Obese insulin-resistant subjects without frank diabetes or sleep apnoea demonstrate preclinical elevations in pharyngeal collapsibility, which may increase their susceptibility to sleep apnoea. Our findings suggest that insulin resistance could play a significant role in sleep apnoea pathogenesis by generating requisite elevations in pharyngeal collapsibility.
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Affiliation(s)
- Oscar L Llanos
- Dept of Medicine, University of Arkansas, Little Rock, AR, USA
| | | | - Edmarie Guzmán-Vélez
- Dept of Psychological and Brain Sciences, University of Iowa, Iowa City, IA, USA
| | - Susheel P Patil
- Division of Pulmonary and Critical Care Medicine, Dept of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Philip L Smith
- Division of Pulmonary and Critical Care Medicine, Dept of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Thomas Magnuson
- Dept of Surgery, Johns Hopkins University, Baltimore, MD, USA
| | | | | | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Dept of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Alan R Schwartz
- Division of Pulmonary and Critical Care Medicine, Dept of Medicine, Johns Hopkins University, Baltimore, MD, USA
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18
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Abstract
Novel concepts and technological advances have the potential to change the landscape on which clinical sleep medicine is practiced. Screening for sleep apnea will take advantage of readily available mobile telephone technology (sound, accelerometers) to enable widespread recognition of sleep-disordered breathing. Advanced computer-assisted scoring algorithms will improve efficiency and reliability of sleep apnea diagnoses. As the field adopts a personalized approach to therapies, methods to determine the mechanisms of sleep apnea in individuals will be developed-utilizing simplified tests and available recordings-with the promise of predicting outcomes of novel therapies.
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Affiliation(s)
- Scott A Sands
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital and Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA; Department of Allergy, Immunology and Respiratory Medicine and Central Clinical School, The Alfred and Monash University, 55 Commercial Road, Prahran, Victoria 3181, Australia.
| | - Robert L Owens
- Division of Pulmonary and Critical Care Medicine, University of California San Diego, 9500 Gilman Dr La Jolla, CA 92093, USA
| | - Atul Malhotra
- Division of Pulmonary and Critical Care Medicine, University of California San Diego, 9500 Gilman Dr La Jolla, CA 92093, USA
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19
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Schorr F, Kayamori F, Hirata RP, Danzi-Soares NJ, Gebrim EM, Moriya HT, Malhotra A, Lorenzi-Filho G, Genta PR. Different Craniofacial Characteristics Predict Upper Airway Collapsibility in Japanese-Brazilian and White Men. Chest 2016; 149:737-46. [PMID: 26291487 DOI: 10.1378/chest.15-0638] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND OSA pathogenesis is complex and may vary according to ethnicity. The anatomic component predisposing to OSA is the result of the interaction between bony structure and upper airway soft tissues and can be assessed using passive critical closing pressure (Pcrit). We hypothesized that Japanese-Brazilians and whites present different predictors of upper airway collapsibility, suggesting different causal pathways to developing OSA in these two groups. METHODS Male Japanese-Brazilians (n = 39) and whites (n = 39) matched for age and OSA severity were evaluated by full polysomnography, Pcrit, and upper airway and abdomen CT scans for determination of upper airway anatomy and abdominal fat, respectively. RESULTS Pcrit was similar between the Japanese-Brazilians and the whites (-1.0 ± 3.3 cm H2O vs -0.4 ± 3.1 cm H2O, P = .325). The Japanese-Brazilians presented smaller upper airway bony dimensions (cranial base, maxillary, and mandibular lengths), whereas the whites presented larger upper airway soft tissue (tongue length and volume) and a greater imbalance between tongue and mandible (tongue/mandibular volume ratio). The cranial base angle was associated with Pcrit only among the Japanese-Brazilians (r = -0.535, P < .01). The tongue/mandibular volume ratio was associated with Pcrit only among the whites (r = 0.460, P < .01). Obesity-related variables (visceral fat, BMI, and neck and waist circumferences) showed a similar correlation with Pcrit in the Japanese-Brazilians and the whites. CONCLUSIONS Japanese-Brazilians and whites present different predictors of upper airway collapsibility. Although craniofacial bony restriction influenced Pcrit only in the Japanese-Brazilians, an anatomic imbalance between tongue and mandible volume influenced Pcrit among the whites. These findings may have therapeutic implications regarding how to improve the anatomic predisposition to OSA across ethnicities.
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Affiliation(s)
- Fabiola Schorr
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo School of Medicine, São Paul, Brazil
| | - Fabiane Kayamori
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo School of Medicine, São Paul, Brazil
| | - Raquel P Hirata
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo School of Medicine, São Paul, Brazil
| | - Naury J Danzi-Soares
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo School of Medicine, São Paul, Brazil
| | - Eloisa M Gebrim
- Radiology Institute (InRad), Hospital das Clínicas, University of São Paulo School of Medicine, São Paul, Brazil
| | - Henrique T Moriya
- Biomedical Engineering Laboratory, University of São Paulo, São Paulo, Brazil
| | - Atul Malhotra
- Department of Pulmonary and Critical Care Medicine, University of California San Diego, La Jolla, CA
| | - Geraldo Lorenzi-Filho
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo School of Medicine, São Paul, Brazil
| | - Pedro R Genta
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo School of Medicine, São Paul, Brazil.
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20
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Pham LV, Schwartz AR. The pathogenesis of obstructive sleep apnea. J Thorac Dis 2015; 7:1358-72. [PMID: 26380762 DOI: 10.3978/j.issn.2072-1439.2015.07.28] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/17/2015] [Indexed: 12/18/2022]
Abstract
Obstructive sleep apnea (OSA) is a major source of cardiovascular morbidity and mortality, and represents an increasing burden on health care resources. Understanding underlying pathogenic mechanisms of OSA will ultimately allow for the development of rational therapeutic strategies. In this article, we review current concepts about the pathogenesis of OSA. Specifically, we consider the evidence that the upper airway plays a primary role in OSA pathogenesis and provide a framework for modelling its biomechanical properties and propensity to collapse during sleep. Anatomical and neuromuscular factors that modulate upper airway obstruction are also discussed. Finally, we consider models of periodic breathing, and elaborate generalizable mechanisms by which upper airway obstruction destabilizes respiratory patterns during sleep. In our model, upper airway obstruction triggers a mismatch between ventilatory supply and demand. In this model, trade-offs between maintaining sleep stability or ventilation can account for a full range of OSA disease severity and expression. Recurrent arousals and transient increases in airway patency may restore ventilation between periods of sleep, while alterations in neuromuscular and arousal responses to upper airway obstruction may improve sleep stability at still suboptimal levels of ventilation.
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Affiliation(s)
- Luu V Pham
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Sleep Disorders Center, Johns Hopkins University, Baltimore, Maryland, USA
| | - Alan R Schwartz
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Sleep Disorders Center, Johns Hopkins University, Baltimore, Maryland, USA
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21
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Biselli P, Grossman PR, Kirkness JP, Patil SP, Smith PL, Schwartz AR, Schneider H. The effect of increased lung volume in chronic obstructive pulmonary disease on upper airway obstruction during sleep. J Appl Physiol (1985) 2015; 119:266-71. [PMID: 26048975 PMCID: PMC4526705 DOI: 10.1152/japplphysiol.00455.2014] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 05/31/2015] [Indexed: 12/18/2022] Open
Abstract
Patients with chronic obstructive pulmonary disease (COPD) exhibit increases in lung volume due to expiratory airflow limitation. Increases in lung volumes may affect upper airway patency and compensatory responses to inspiratory flow limitation (IFL) during sleep. We hypothesized that COPD patients have less collapsible airways inversely proportional to their lung volumes, and that the presence of expiratory airflow limitation limits duty cycle responses to defend ventilation in the presence of IFL. We enrolled 18 COPD patients and 18 controls, matched by age, body mass index, sex, and obstructive sleep apnea disease severity. Sleep studies, including quantitative assessment of airflow at various nasal pressure levels, were conducted to determine upper airway mechanical properties [passive critical closing pressure (Pcrit)] and for quantifying respiratory timing responses to experimentally induced IFL. COPD patients had lower passive Pcrit than their matched controls (COPD: -2.8 ± 0.9 cmH2O; controls: -0.5 ± 0.5 cmH2O, P = 0.03), and there was an inverse relationship of subject's functional residual capacity and passive Pcrit (-1.7 cmH2O/l increase in functional residual capacity, r(2) = 0.27, P = 0.002). In response to IFL, inspiratory duty cycle increased more (P = 0.03) in COPD patients (0.40 to 0.54) than in controls (0.41 to 0.51) and led to a marked reduction in expiratory time from 2.5 to 1.5 s (P < 0.01). COPD patients have a less collapsible airway and a greater, not reduced, compensatory timing response during upper airway obstruction. While these timing responses may reduce hypoventilation, it may also increase the risk for developing dynamic hyperinflation due to a marked reduction in expiratory time.
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Affiliation(s)
- Paolo Biselli
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland; and Hospital Universitário, University of Sao Paulo, São Paulo, Brazil
| | - Peter R Grossman
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland; and
| | - Jason P Kirkness
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland; and
| | - Susheel P Patil
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland; and
| | - Philip L Smith
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland; and
| | - Alan R Schwartz
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland; and
| | - Hartmut Schneider
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary and Critical Care Medicine, Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland; and
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22
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Kirkness JP. Obesity-related ventilatory phenotypes of sleep-disordered breathing. Am J Respir Crit Care Med 2014; 190:853-4. [PMID: 25317463 DOI: 10.1164/rccm.201409-1674ed] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Jason P Kirkness
- 1 Johns Hopkins School of Medicine Johns Hopkins University Baltimore, Maryland
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23
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Relationship of left atrial size to obstructive sleep apnea severity in end-stage renal disease. Sleep Med 2014; 15:1314-8. [DOI: 10.1016/j.sleep.2014.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 06/24/2014] [Accepted: 07/03/2014] [Indexed: 11/24/2022]
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24
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Hypopnea: 'rule of thumb' or ruler and plumb? Sleep Breath 2014; 18:683-5. [PMID: 24671369 DOI: 10.1007/s11325-014-0974-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 03/06/2014] [Accepted: 03/07/2014] [Indexed: 10/25/2022]
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25
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Abstract
Obstructive sleep apnoea is an increasingly common disorder of repeated upper airway collapse during sleep, leading to oxygen desaturation and disrupted sleep. Features include snoring, witnessed apnoeas, and sleepiness. Pathogenesis varies; predisposing factors include small upper airway lumen, unstable respiratory control, low arousal threshold, small lung volume, and dysfunctional upper airway dilator muscles. Risk factors include obesity, male sex, age, menopause, fluid retention, adenotonsillar hypertrophy, and smoking. Obstructive sleep apnoea causes sleepiness, road traffic accidents, and probably systemic hypertension. It has also been linked to myocardial infarction, congestive heart failure, stroke, and diabetes mellitus though not definitively. Continuous positive airway pressure is the treatment of choice, with adherence of 60-70%. Bi-level positive airway pressure or adaptive servo-ventilation can be used for patients who are intolerant to continuous positive airway pressure. Other treatments include dental devices, surgery, and weight loss.
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Affiliation(s)
- Amy S Jordan
- University of Melbourne, Melbourne, VIC, Australia; Institute for Breathing and Sleep, Melbourne, VIC, Australia.
| | - David G McSharry
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA; Letterkenny General Hospital, County Donegal, Ireland
| | - Atul Malhotra
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA; University of California, San Diego, CA, USA
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26
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Shapiro SD, Chin CH, Kirkness JP, McGinley BM, Patil SP, Polotsky VY, Biselli PJC, Smith PL, Schneider H, Schwartz AR. Leptin and the control of pharyngeal patency during sleep in severe obesity. J Appl Physiol (1985) 2014; 116:1334-41. [PMID: 24557793 DOI: 10.1152/japplphysiol.00958.2013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
RATIONALE Obesity imposes mechanical loads on the upper airway, resulting in flow limitation and obstructive sleep apnea (OSA). In previous animal models, leptin has been considered to serve as a stimulant of ventilation and may prevent respiratory depression during sleep. We hypothesized that variations in leptin concentration among similarly obese individuals will predict differences in compensatory responses to upper airway obstruction during sleep. METHODS An observational study was conducted in 23 obese women [body mass index (BMI): 46 ± 3 kg/m(2), age: 41 ± 12 yr] and 3 obese men (BMI: 46 ± 3 kg/m(2), age: 43 ± 4 yr). Subjects who were candidates for bariatric surgery were recruited to determine upper airway collapsibility under hypotonic conditions [pharyngeal critical pressure (passive PCRIT)], active neuromuscular responses to upper airway obstruction during sleep, and overnight fasting serum leptin levels. Compensatory responses were defined as the differences in peak inspiratory airflow (ΔVImax), inspired minute ventilation (ΔVI), and pharyngeal critical pressure (ΔPCRIT) between the active and passive conditions. RESULTS Leptin concentration was not associated with sleep disordered breathing severity, passive PCRIT, or baseline ventilation. In the women, increases in serum leptin concentrations were significantly associated with increases in ΔVImax (r(2) = 0.44, P < 0.001), ΔVI (r(2) = 0.40, P < 0.001), and ΔPCRIT (r(2) = 0.19, P < 0.04). These responses were independent of BMI, waist-to-hip ratio, neck circumference, or sagittal girth. CONCLUSION Leptin may augment neural compensatory mechanisms in response to upper airway obstruction, minimizing upper airway collapse, and/or mitigating potential OSA severity. Variability in leptin concentration among similarly obese individuals may contribute to differences in OSA susceptibility.
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Affiliation(s)
- Steven D Shapiro
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Chien-Hung Chin
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan; and
| | - Jason P Kirkness
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Brian M McGinley
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Susheel P Patil
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Vsevolod Y Polotsky
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Paolo Jose Cesare Biselli
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland; Hospital Universitario (HU-USP), Sao Paulo, Brasil
| | - Philip L Smith
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Hartmut Schneider
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Alan R Schwartz
- Johns Hopkins Sleep Disorders Center, Division of Pulmonary & Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland;
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Schwartz AR, Smith PL. CrossTalk proposal: the human upper airway does behave like a Starling resistor during sleep. J Physiol 2013; 591:2229-32. [PMID: 23740879 DOI: 10.1113/jphysiol.2012.250654] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Alan R Schwartz
- Division of Pulmonary, Critical Care and Sleep Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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Mazzuca E, Battaglia S, Marrone O, Marotta AM, Castrogiovanni A, Esquinas C, Barcelò A, Barbé F, Bonsignore MR. Gender-specific anthropometric markers of adiposity, metabolic syndrome and visceral adiposity index (VAI) in patients with obstructive sleep apnea. J Sleep Res 2013; 23:13-21. [PMID: 24118617 DOI: 10.1111/jsr.12088] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Accepted: 08/06/2013] [Indexed: 12/16/2022]
Abstract
Obstructive sleep apnea often coexists with visceral adiposity and metabolic syndrome. In this study, we analysed gender-related differences in anthropometrics according to sleep apnea severity and metabolic abnormalities. In addition, the visceral adiposity index, a recently introduced marker of cardiometabolic risk, was analysed. Consecutive subjects with suspected obstructive sleep apnea (n = 528, 423 males, mean age ± standard deviation: 51.3 ± 12.8 years, body mass index: 31.0 ± 6.2 kg m(-2) ) were studied by full polysomnography (apnea-hypopnea index 43.4 ± 27.6 h(-1) ). Variables of general and visceral adiposity were measured (body mass index, neck, waist and hip circumferences, waist-to-hip ratio). The visceral adiposity index was calculated, and metabolic syndrome was assessed (NCEP-ATP III criteria). The sample included controls (apnea-hypopnea index <10 h(-1) , n = 55), and patients with mild-moderate (apnea-hypopnea index 10-30 h(-1) , n = 144) and severe sleep apnea (apnea-hypopnea index >30 h(-1) , n = 329). When anthropometric variables were entered in stepwise multiple regression, body mass index, waist circumference and diagnosis of metabolic syndrome were associated with the apnea-hypopnea index in men (adjusted R(2) = 0.308); by contrast, only hip circumference and height-normalized neck circumference were associated with sleep apnea severity in women (adjusted R(2) = 0.339). These results changed little in patients without metabolic syndrome; conversely, waist circumference was the only correlate of apnea-hypopnea index in men and women with metabolic syndrome. The visceral adiposity index increased with insulin resistance, but did not predict sleep apnea severity. These data suggest gender-related interactions between obstructive sleep apnea, obesity and metabolic abnormalities. The visceral adiposity index was a good marker of metabolic syndrome, but not of obstructive sleep apnea.
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Affiliation(s)
- Emilia Mazzuca
- Biomedical Department of Internal and Specialistic Medicine (DIBIMIS), Section of Pneumology, University of Palermo, Palermo, Italy
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Wellman A, Edwards BA, Sands SA, Owens RL, Nemati S, Butler J, Passaglia CL, Jackson AC, Malhotra A, White DP. A simplified method for determining phenotypic traits in patients with obstructive sleep apnea. J Appl Physiol (1985) 2013; 114:911-22. [PMID: 23349453 PMCID: PMC3633440 DOI: 10.1152/japplphysiol.00747.2012] [Citation(s) in RCA: 156] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 01/21/2013] [Indexed: 02/04/2023] Open
Abstract
We previously published a method for measuring several physiological traits causing obstructive sleep apnea (OSA). The method, however, had a relatively low success rate (76%) and required mathematical modeling, potentially limiting its application. This paper presents a substantial revision of that technique. To make the measurements, continuous positive airway pressure (CPAP) was manipulated during sleep to quantify 1) eupneic ventilatory demand, 2) the level of ventilation at which arousals begin to occur, 3) ventilation off CPAP (nasal pressure = 0 cmH(2)O) when the pharyngeal muscles are activated during sleep, and 4) ventilation off CPAP when the pharyngeal muscles are relatively passive. These traits could be determined in all 13 participants (100% success rate). There was substantial intersubject variability in the reduction in ventilation that individuals could tolerate before having arousals (difference between ventilations #1 and #2 ranged from 0.7 to 2.9 liters/min) and in the amount of ventilatory compensation that individuals could generate (difference between ventilations #3 and #4 ranged from -0.5 to 5.5 liters/min). Importantly, the measurements accurately reflected clinical metrics; the difference between ventilations #2 and #3, a measure of the gap that must be overcome to achieve stable breathing during sleep, correlated with the apnea-hypopnea index (r = 0.9, P < 0.001). An additional procedure was added to the technique to measure loop gain (sensitivity of the ventilatory control system), which allowed arousal threshold and upper airway gain (response of the upper airway to increasing ventilatory drive) to be quantified as well. Of note, the traits were generally repeatable when measured on a second night in 5 individuals. This technique is a relatively simple way of defining mechanisms underlying OSA and could potentially be used in a clinical setting to individualize therapy.
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Affiliation(s)
- Andrew Wellman
- Division of Sleep Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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White LH, Bradley TD. Role of nocturnal rostral fluid shift in the pathogenesis of obstructive and central sleep apnoea. J Physiol 2013; 591:1179-93. [PMID: 23230237 PMCID: PMC3607865 DOI: 10.1113/jphysiol.2012.245159] [Citation(s) in RCA: 202] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 12/06/2012] [Indexed: 12/25/2022] Open
Abstract
Obstructive sleep apnoea (OSA) is common in the general population and increases the risk of motor vehicle accidents due to hypersomnolence from sleep disruption, and risk of cardiovascular diseases owing to repetitive hypoxia, sympathetic nervous system activation, and systemic inflammation. In contrast, central sleep apnoea (CSA) is rare in the general population. Although their pathogenesis is multifactorial, the prevalence of both OSA and CSA is increased in patients with fluid retaining states, especially heart failure, where they are associated with increased mortality risk. This observation suggests that fluid retention may contribute to the pathogenesis of both OSA and CSA. According to this hypothesis, during the day fluid accumulates in the intravascular and interstitial spaces of the legs due to gravity, and upon lying down at night redistributes rostrally, again owing to gravity. Some of this fluid may accumulate in the neck, increasing tissue pressure and causing the upper airway to narrow, thereby increasing its collapsibility and predisposing to OSA. In heart failure patients, with increased rostral fluid shift, fluid may additionally accumulate in the lungs, provoking hyperventilation and hypocapnia, driving below the apnoea threshold, leading to CSA. This review article will explore mechanisms by which overnight rostral fluid shift, and its prevention, can contribute to the pathogenesis and therapy of sleep apnoea.
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Affiliation(s)
- Laura H White
- Department of Medicine, University Health Network Toronto General Hospital, Rehabilitation Institute, University of Toronto, Ontario, Canada
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