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Lim J, Alshaer H, Ghahjaverestan NM, Bradley TD. Relationship between airflow limitation in response to upper airway negative pressure during wakefulness and obstructive sleep apnea severity. Sleep Breath 2024; 28:231-239. [PMID: 37548919 DOI: 10.1007/s11325-023-02892-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 07/12/2023] [Accepted: 07/24/2023] [Indexed: 08/08/2023]
Abstract
PURPOSE The objective was to determine if alteration in airflow induced by negative pressure (NP) applied to participants' upper airways during wakefulness, is related to obstructive sleep apnea (OSA) severity as determined by the apnea-hypopnea index (AHI). METHODS Adults 18 years of age or greater were recruited. All participants underwent overnight polysomnography to assess their apnea-hypopnea index (AHI). While awake, participants were twice exposed, orally, to -3 cm H2O of NP for five full breaths. The ratio of the breathing volumes of the last two breaths during NP exposure to the last two breaths prior to NP exposure was deemed the NP ratio (NPR). RESULTS Eighteen participants were enrolled. A strong relationship between the AHI and the exponentially transformed NPR (ExpNPR) for all participants was observed (R2 = 0.55, p < 0.001). A multivariable model using the independent variable ExpNPR, age, body mass index and sex accounted for 81% of variability in AHI (p = 0.0006). A leave-one-subject-out cross-validation analysis revealed that predicted AHI using the multivariable model, and actual AHI from participants' polysomnograms, were strongly related (R2 = 0.72, p < 0.001). CONCLUSION We conclude that ExpNPR, was strongly related to the AHI, independently of demographic factors known to be related to the AHI.
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Affiliation(s)
- Jan Lim
- KITE Sleep Research Laboratory, Toronto Rehabilitation Institute of the University Health Network Toronto General Hospital, 200 Elizabeth St., Room 9N-943, Toronto, ON, M5G 2C4, Canada
| | | | - Nasim Montazeri Ghahjaverestan
- KITE Sleep Research Laboratory, Toronto Rehabilitation Institute of the University Health Network Toronto General Hospital, 200 Elizabeth St., Room 9N-943, Toronto, ON, M5G 2C4, Canada
- Department of Medicine, Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - T Douglas Bradley
- KITE Sleep Research Laboratory, Toronto Rehabilitation Institute of the University Health Network Toronto General Hospital, 200 Elizabeth St., Room 9N-943, Toronto, ON, M5G 2C4, Canada.
- Toronto General Hospital of the University Health Network, Toronto, ON, Canada.
- Department of Medicine, University of Toronto, Toronto, ON, Canada.
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2
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Kent DT, Scott WC, Zealear D, Schwartz AR. Ansa cervicalis stimulation increases pharyngeal patency in patients with obstructive sleep apnea. J Appl Physiol (1985) 2021; 131:487-495. [PMID: 34197226 DOI: 10.1152/japplphysiol.00076.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Hypoglossal nerve stimulation (HNS) is an alternative treatment option for obstructive sleep apnea (OSA) that reduces pharyngeal collapsibility, but HNS nonresponders often demonstrate continued retropalatal and lateral pharyngeal wall collapse. Recent evidence suggests that caudal pharyngeal traction with sternothyroid muscle contraction via ansa cervicalis stimulation (ACS) can also stabilize the pharynx, but the underlying mechanisms have not been elucidated. Our objective was to evaluate the effect of ACS on pharyngeal patency during expiration when the airway is most hypotonic. Eight participants with OSA underwent sustained ultrasound-guided fine-wire stimulation of the medial branch of the right hypoglossal nerve with and without transient stimulation of the branch of the ansa cervicalis nerve plexus innervating the right sternothyroid muscle during drug-induced sleep endoscopy. Airway cross-sectional area and expiratory airflow (V̇e) were measured from endoscopy video with ImageJ and pneumotachometry, respectively. ACS significantly increased retropalatal cross-sectional area (CSARP) to 211% [159-263] of unstimulated CSARP (P < 0.05). Adding ACS to HNS increased CSARP from baseline by 341% [244-439] (P < 0.05), a 180% [133-227] increase over isolated HNS (P < 0.05). ACS increased V̇e from baseline by 177% [138-217] P < 0.05). Adding ACS to HNS increased V̇e by 254% [207-301], reflecting decreases in pharyngeal collapsibility. Combining ACS with HNS increased retropalatal cross-sectional area and increased expiratory airflow, suggesting decreases in pharyngeal collapsibility. Our findings suggest that ACS exerts caudal traction on the upper airway through sternothyroid muscle contraction and that it may augment HNS efficacy in patients with OSA.NEW & NOTEWORTHY Ansa cervicalis stimulation (ACS) is a recently proposed neurostimulation mechanism for generating caudal pharyngeal traction that may benefit patients with obstructive sleep apnea. Here, we document endoscopic findings with ACS during drug-induced sleep endoscopy and additionally detail the effects of ACS on expiratory airflow, when the pharynx is known to be most hypotonic.
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Affiliation(s)
- David T Kent
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - William C Scott
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - David Zealear
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Alan R Schwartz
- Department of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania.,Universidad Peruana Cayetano Heredia School of Medicine, Lima, Peru
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3
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Kent DT, Zealear D, Schwartz AR. Ansa Cervicalis and Hypoglossal Nerve Stimulation in a Patient With Obstructive Sleep Apnea. Otolaryngol Head Neck Surg 2021; 165:602-604. [PMID: 33494663 DOI: 10.1177/0194599820986578] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- David T Kent
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - David Zealear
- Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alan R Schwartz
- Department of Otorhinolaryngology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,School of Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru
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4
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Osman AM, Carberry JC, Gandevia SC, Butler JE, Eckert DJ. Changes in pharyngeal collapsibility and genioglossus reflex responses to negative pressure during the respiratory cycle in obstructive sleep apnoea. J Physiol 2020; 598:567-580. [DOI: 10.1113/jp278433] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 11/11/2019] [Indexed: 11/08/2022] Open
Affiliation(s)
- Amal M. Osman
- Neuroscience Research Australia (NeuRA) Sydney NSW Australia
- School of Medical Sciences University of New South Wales Sydney NSW Australia
- Flinders University Adelaide Institute for Sleep Health Bedford Park SA Australia
- CRC for Alertness Safety and Productivity Melbourne Australia
| | - Jayne C. Carberry
- Neuroscience Research Australia (NeuRA) Sydney NSW Australia
- School of Medical Sciences University of New South Wales Sydney NSW Australia
- Flinders University Adelaide Institute for Sleep Health Bedford Park SA Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia (NeuRA) Sydney NSW Australia
- School of Medical Sciences University of New South Wales Sydney NSW Australia
| | - Jane E. Butler
- Neuroscience Research Australia (NeuRA) Sydney NSW Australia
- School of Medical Sciences University of New South Wales Sydney NSW Australia
| | - Danny J. Eckert
- Neuroscience Research Australia (NeuRA) Sydney NSW Australia
- School of Medical Sciences University of New South Wales Sydney NSW Australia
- Flinders University Adelaide Institute for Sleep Health Bedford Park SA Australia
- CRC for Alertness Safety and Productivity Melbourne Australia
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5
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Eastwood PR, Barnes M, MacKay SG, Wheatley JR, Hillman DR, Nguyên XL, Lewis R, Campbell MC, Pételle B, Walsh JH, Jones AC, Palme CE, Bizon A, Meslier N, Bertolus C, Maddison KJ, Laccourreye L, Raux G, Denoncin K, Attali V, Gagnadoux F, Launois SH. Bilateral hypoglossal nerve stimulation for treatment of adult obstructive sleep apnoea. Eur Respir J 2020; 55:13993003.01320-2019. [PMID: 31601716 PMCID: PMC6949509 DOI: 10.1183/13993003.01320-2019] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/21/2019] [Indexed: 01/10/2023]
Abstract
BACKGROUND AND AIM Hypoglossal nerve stimulation (HNS) decreases obstructive sleep apnoea (OSA) severity via genioglossus muscle activation and decreased upper airway collapsibility. This study assessed the safety and effectiveness at 6 months post-implantation of a novel device delivering bilateral HNS via a small implanted electrode activated by a unit worn externally, to treat OSA: the Genio™ system. METHODS This prospective, open-label, non-randomised, single-arm treatment study was conducted at eight centres in three countries (Australia, France and the UK). Primary outcomes were incidence of device-related serious adverse events and change in the apnoea-hypopnoea index (AHI). The secondary outcome was the change in the 4% oxygen desaturation index (ODI). Additional outcomes included measures of sleepiness, quality of life, snoring and device use. This trial was registered with ClinicalTrials.gov, number NCT03048604. RESULTS 22 out of 27 implanted participants (63% male, aged 55.9±12.0 years, body mass index (BMI) 27.4±3.0 kg·m-2) completed the protocol. At 6 months BMI was unchanged (p=0.85); AHI decreased from 23.7±12.2 to 12.9±10.1 events·h-1, a mean change of 10.8 events·h-1 (p<0.001); and ODI decreased from 19.1±11.2 to 9.8±6.9 events·h-1, a mean change of 9.3 events·h-1 (p<0.001). Daytime sleepiness (Epworth Sleepiness Scale; p=0.01) and sleep-related quality of life (Functional Outcomes of Sleep Questionnaire-10; p=0.02) both improved significantly. The number of bed partners reporting loud, very intense snoring, or leaving the bedroom due to participant snoring decreased from 96% to 35%. 91% of participants reported device use >5 days per week, and 77% reported use for >5 h per night. No device-related serious adverse events occurred during the 6-month post-implantation period. CONCLUSIONS Bilateral HNS using the Genio™ system reduces OSA severity and improves quality of life without device-related complications. The results are comparable with previously published HNS systems despite minimal implanted components and a simple stimulation algorithm.
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Affiliation(s)
- Peter R Eastwood
- Centre for Sleep Science, School of Human Sciences, University of Western Australia, Perth, Australia .,West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Perth, Australia
| | - Maree Barnes
- Institute for Breathing and Sleep, Austin Hospital, Heidelberg, Australia.,University of Melbourne, Parkville, Australia
| | - Stuart G MacKay
- Illawarra ENT Head and Neck Clinic, Wollongong, Australia.,Wollongong Hospital, Illawarra Shoalhaven Local Health District (ISLHD), Wollongong, Australia.,Graduate School of Medicine, University of Wollongong, Wollongong, Australia.,Woolcock Institute of Medical Research, Glebe, Australia
| | - John R Wheatley
- Dept of Respiratory and Sleep Medicine, Westmead Hospital, Westmead, Australia.,University of Sydney at Westmead Hospital, Westmead, Australia.,Ludwig Engel Centre for Respiratory Research, The Westmead Institute for Medical Research, Westmead, Australia
| | - David R Hillman
- Centre for Sleep Science, School of Human Sciences, University of Western Australia, Perth, Australia.,West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Perth, Australia
| | - Xuân-Lan Nguyên
- Unité de Somnologie et Fonction Respiratoire, Hopital St Antoine, Paris, France.,Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
| | - Richard Lewis
- Dept Otolaryngology, Head and Neck Surgery, Royal Perth Hospital, Perth, Australia.,Hollywood Private Hospital, Perth, Australia
| | - Matthew C Campbell
- Institute for Breathing and Sleep, Austin Hospital, Heidelberg, Australia.,University of Melbourne, Parkville, Australia
| | - Boris Pételle
- Service ORL Chirurgie de la Face et du Cou, Hôpital Tenon, AP-HP, Paris, Sorbonne Université, Paris, France
| | - Jennifer H Walsh
- Centre for Sleep Science, School of Human Sciences, University of Western Australia, Perth, Australia.,West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Perth, Australia
| | - Andrew C Jones
- Illawarra ENT Head and Neck Clinic, Wollongong, Australia.,Wollongong Hospital, Illawarra Shoalhaven Local Health District (ISLHD), Wollongong, Australia.,Graduate School of Medicine, University of Wollongong, Wollongong, Australia
| | - Carsten E Palme
- University of Sydney at Westmead Hospital, Westmead, Australia.,The Dept of Otolaryngology Head Neck Surgery, Westmead Hospital, Westmead, Australia
| | - Alain Bizon
- Dept Otolaryngology, Head and Neck Surgery, University Hospital of Angers, Angers, France
| | - Nicole Meslier
- Dept of Respiratory and Sleep Medicine, University Hospital of Angers, Angers, France.,INSERM UMR 1063 "SOPAM", University of Angers, Angers, France
| | - Chloé Bertolus
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service des Pathologies du Sommeil (Département "R3S"), Paris, France.,AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Stomatologie et Chirurgie Maxillo-faciale, Paris, France
| | - Kathleen J Maddison
- Centre for Sleep Science, School of Human Sciences, University of Western Australia, Perth, Australia.,West Australian Sleep Disorders Research Institute, Sir Charles Gairdner Hospital, Perth, Australia
| | - Laurent Laccourreye
- Dept Otolaryngology, Head and Neck Surgery, University Hospital of Angers, Angers, France
| | | | | | - Valérie Attali
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France.,AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service des Pathologies du Sommeil (Département "R3S"), Paris, France
| | - Frédéric Gagnadoux
- Dept of Respiratory and Sleep Medicine, University Hospital of Angers, Angers, France.,INSERM UMR 1063 "SOPAM", University of Angers, Angers, France
| | - Sandrine H Launois
- Unité de Somnologie et Fonction Respiratoire, Hopital St Antoine, Paris, France.,Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
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6
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Khemliche H, Ouayoun MC. [Physiopathology of obstructive sleep apnea syndrome]. Orthod Fr 2019; 90:263-271. [PMID: 34643514 DOI: 10.1051/orthodfr/2019028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
An excellent grasp of the physiopathology of obstructive sleep apnea syndrome (OSAS) is essential to understanding its diagnostic and therapeutic modalities. A systematic review of the literature was performed on data specific to humans. Two aspects are involved: on one hand, the mechanisms contributing to intermittent obstruction of the upper airways (UA) during sleep and, on the other hand, the impact of this obstruction, e.g. neurocognitive disorders, cardiovascular disease and metabolic dysregulation. UA obstruction can be explained by anatomical, mechanical and neuro-functional conditions, especially the proprioceptive and chemical feedback of UA neuromuscular activity. Our understanding of the impact of OSAS has benefited from the recently developed concepts of oxidative stress and low-grade systemic inflammation, the discovery of hypoxia-sensitive agents and of the role of cytokines. The onset of this chain of events is determined by chronic intermittent hypoxia.
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Affiliation(s)
| | - Michel-Christian Ouayoun
- Université Sorbonne Paris Cité, Faculté de médecine Léonard de Vinci, 74 rue Marcel Cachin, 93017 Bobigny cedex, France
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7
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Pilarski JQ, Leiter JC, Fregosi RF. Muscles of Breathing: Development, Function, and Patterns of Activation. Compr Physiol 2019; 9:1025-1080. [PMID: 31187893 DOI: 10.1002/cphy.c180008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This review is a comprehensive description of all muscles that assist lung inflation or deflation in any way. The developmental origin, anatomical orientation, mechanical action, innervation, and pattern of activation are described for each respiratory muscle fulfilling this broad definition. In addition, the circumstances in which each muscle is called upon to assist ventilation are discussed. The number of "respiratory" muscles is large, and the coordination of respiratory muscles with "nonrespiratory" muscles and in nonrespiratory activities is complex-commensurate with the diversity of activities that humans pursue, including sleep (8.27). The capacity for speech and adoption of the bipedal posture in human evolution has resulted in patterns of respiratory muscle activation that differ significantly from most other animals. A disproportionate number of respiratory muscles affect the nose, mouth, pharynx, and larynx, reflecting the vital importance of coordinated muscle activity to control upper airway patency during both wakefulness and sleep. The upright posture has freed the hands from locomotor functions, but the evolutionary history and ontogeny of forelimb muscles pervades the patterns of activation and the forces generated by these muscles during breathing. The distinction between respiratory and nonrespiratory muscles is artificial, as many "nonrespiratory" muscles can augment breathing under conditions of high ventilator demand. Understanding the ontogeny, innervation, activation patterns, and functions of respiratory muscles is clinically useful, particularly in sleep medicine. Detailed explorations of how the nervous system controls the multiple muscles required for successful completion of respiratory behaviors will continue to be a fruitful area of investigation. © 2019 American Physiological Society. Compr Physiol 9:1025-1080, 2019.
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Affiliation(s)
- Jason Q Pilarski
- Department of Biological and Dental Sciences, Idaho State University Pocatello, Idaho, USA
| | - James C Leiter
- Department of Molecular and Systems Biology, The Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Ralph F Fregosi
- Departments of Physiology and Neuroscience, The University of Arizona, Tucson, Arizona, USA
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8
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Kitipornchai L, Jones A, MacKay SG. Patient Phenotyping in OSA. CURRENT OTORHINOLARYNGOLOGY REPORTS 2019. [DOI: 10.1007/s40136-019-00221-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Chen NH, Lin SW, Chuang LP, Cistulli PA, Hsieh MJ, Kao KC, Liao YF, Li LF, Yang CT. Pharyngeal distensibility during expiration is an independent predictor of the severity of obstructive sleep apnoea. Respirology 2019; 24:582-589. [PMID: 30675958 DOI: 10.1111/resp.13474] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/24/2018] [Accepted: 12/04/2018] [Indexed: 01/27/2023]
Abstract
BACKGROUND AND OBJECTIVE Pharyngeal distensibility and collapsibility reflect the passive properties of tissue in the airway, are an indicator of the ease with which an airway can be deformed and are related to the severity of obstructive sleep apnoea (OSA). During normal tidal respiration, the collapsibility of the pharynx during expiration is passive without confounding by neuromuscular activation that occurs during inspiration. We evaluated the distensibility and collapsibility of the upper airway in subjects with OSA during wakefulness using sophisticated dynamic computed tomography (CT) imaging. We hypothesized that the dynamic changes of the upper airway during expiration would be related to the severity of OSA. METHODS Twenty-three patients with OSA and eight normal subjects underwent simultaneous measurement of respiratory flow and airway calibre using ultrafast CT. The change in pharyngeal cross-sectional area divided by the change in concomitant flow (as distensibility or collapsibility) was measured and compared across different severities of OSA. RESULTS The slope of this relationship between delta area and delta flow during expiration was significantly higher in severe OSA when compared with normal controls and mild-moderate OSA. Differences in airway distensibility or collapsibility between severity groups were significant in expiration but not in inspiration. Distensibility or collapsibility contributed most to the apnoea-hypopnoea index in regression modelling. Age, gender, and body mass index (BMI) were not significant independent predictors. CONCLUSION Our study demonstrates that airway distensibility during the expiratory phase of awake respiration is correlated with the severity of OSA.
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Affiliation(s)
- Ning-Hung Chen
- Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Respiratory Therapy, Chang Gung University, Taoyuan, Taiwan
| | - Shih-Wei Lin
- Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Li-Pang Chuang
- Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Peter A Cistulli
- Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, Sydney, NSW, Australia.,Charles Perkins Centre, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Meng-Jer Hsieh
- Department of Respiratory Therapy, Chang Gung University, Taoyuan, Taiwan.,Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan
| | - Kuo-Chin Kao
- Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Respiratory Therapy, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Fang Liao
- Sleep Center, Department of Craniofacial Orthodontics, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Li-Fu Li
- Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Cheng-Ta Yang
- Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Respiratory Therapy, Chang Gung University, Taoyuan, Taiwan
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10
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Nishimura Y, Arias RS, Pho H, Pham LV, Curado TF, Polotsky VY, Schwartz AR. A Novel Non-invasive Approach for Measuring Upper Airway Collapsibility in Mice. Front Neurol 2018; 9:985. [PMID: 30524362 PMCID: PMC6256100 DOI: 10.3389/fneur.2018.00985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 10/31/2018] [Indexed: 12/26/2022] Open
Abstract
Introduction: Invasive procedures were previously developed for measuring pharyngeal collapsibility in rodents during expiration, when declining neuromuscular activity makes the airway unstable. We developed a non-invasive approach for streamlining collapsibility measurements by characterizing responses in physiologic markers of dynamic expiratory airflow obstruction to negative nasal pressure challenges. Methods: Anesthetized mice were instrumented to monitor upper airway pressure-flow relationships with head-out plethysmography while nasal pressure was ramped down from ~ +5 to -20 cm H2O over several breaths. Inspiratory and expiratory flow, volume, and timing characteristics were assessed breath-wise. Pcrit was estimated at transitions in expiratory amplitude and timing parameters, and compared to gold standard PCRIT measurements when nasal and tracheal pressures diverged during expiration. Predictions equations were constructed in a development data set (n = 8) and applied prospectively to a validation data set (n = 16) to estimate gold standard PCRIT. Results: The development data demonstrated that abrupt reversals in expiratory duration and tidal volume during nasal pressure ramps predicted gold standard PCRIT measurements. After applying regression equations from the development to a validation dataset, we found that a combination of expiratory amplitude and timing parameters proved to be robust predictors of gold standard PCRIT with minimal bias and narrow confidence intervals. Conclusions: Markers of expiratory airflow obstruction can be used to model upper airway collapsibility, and can provide sensitive measures of changes in airway collapsibility in rodents. This approach streamlines repeated non-invasive PCRIT measurements, and facilitates studies examining the impact of genetic, environmental, and pharmacologic factors on upper airway control.
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Affiliation(s)
- Yoichi Nishimura
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States.,Department of Otolaryngology, Teikyo University Chiba Medical Center, Chiba, Japan
| | - Rafael S Arias
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Huy Pho
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Luu Van Pham
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Thomaz Fleury Curado
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
| | - Alan R Schwartz
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, United States
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11
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Abstract
PURPOSE OF REVIEW In numerous neuromuscular disorders (NMDs), respiratory muscle weakness is present, and acute or chronic respiratory failure may evolve. Very often, respiratory involvement substantially adds to the burden of disease, impairs quality of life, or reduces life expectancy. This article summarizes new aspects of both diagnosis and management of respiratory muscle weakness in patients with NMDs. RECENT FINDINGS Drugs like deflazacort, ataluren, eteplirsen, and nusinersen are now approved treatments for Duchenne Muscular Dystrophy and Spinal Muscular Atrophy, and others are on their way in NMDs. Although observing how innovative drugs will change the natural history of these diseases, including respiratory function over time, adequate symptomatic treatment remains meaningful and is strongly recommended. Physicians should systematically take respiratory involvement into account to improve patients' quality of life and prognosis. SUMMARY First, it is outlined in which subtypes of NMD respiratory muscle dysfunction is particularly relevant. Second, new developments regarding diagnostic procedures, including respiratory muscle strength testing, spirometry, and sleep studies, are covered. Third, this article gives an overview on current concepts of ventilatory support and management of secretions in patients with NMD.
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12
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Azarbarzin A, Sands SA, Marques M, Genta PR, Taranto-Montemurro L, Messineo L, White DP, Wellman A. Palatal prolapse as a signature of expiratory flow limitation and inspiratory palatal collapse in patients with obstructive sleep apnoea. Eur Respir J 2018; 51:13993003.01419-2017. [PMID: 29444914 DOI: 10.1183/13993003.01419-2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/29/2017] [Indexed: 12/20/2022]
Abstract
In some individuals with obstructive sleep apnoea (OSA), the palate prolapses into the velopharynx during expiration, limiting airflow through the nose or shunting it out of the mouth. We hypothesised that this phenomenon causes expiratory flow limitation (EFL) and is associated with inspiratory "isolated" palatal collapse. We also wanted to provide a robust noninvasive means to identify this mechanism of obstruction.Using natural sleep endoscopy, 1211 breaths from 22 OSA patients were scored as having or not having palatal prolapse. The patient-level site of collapse (tongue-related, isolated palate, pharyngeal lateral walls and epiglottis) was also characterised. EFL was quantified using expiratory resistance at maximal epiglottic pressure. A noninvasive EFL index (EFLI) was developed to detect the presence of palatal prolapse and EFL using the flow signal alone. In addition, the validity of using nasal pressure was assessed.A cut-off value of EFLI >0.8 detected the presence of palatal prolapse and EFL with an accuracy of >95% and 82%, respectively. The proportion of breaths with palatal prolapse predicted isolated inspiratory palatal collapse with 90% accuracy.This study demonstrates that expiratory palatal prolapse can be quantified noninvasively, is associated with EFL and predicts the presence of inspiratory isolated palatal collapse.
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Affiliation(s)
- Ali Azarbarzin
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Scott A Sands
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.,Dept of Allergy Immunology and Respiratory Medicine and Central Clinical School, The Alfred and Monash University, Melbourne, Australia
| | - Melania Marques
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.,Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Pedro R Genta
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Luigi Taranto-Montemurro
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Ludovico Messineo
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - David P White
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Andrew Wellman
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
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Brodsky A, Dotan Y, Samri M, Schwartz AR, Oliven A. Differential effects of respiratory and electrical stimulation-induced dilator muscle contraction on mechanical properties of the pharynx in the pig. J Appl Physiol (1985) 2016; 121:606-14. [DOI: 10.1152/japplphysiol.00783.2015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 06/13/2016] [Indexed: 11/22/2022] Open
Abstract
Respiratory stimulation (RS) during sleep often fails to discontinue flow limitation, whereas electrical stimulation (ES) of the hypoglossus (HG) nerve frequently prevents obstruction. The present work compares the effects of RS and HG-ES on pharyngeal mechanics and the relative contribution of tongue muscles and thoracic forces to pharyngeal patency. We determined the pressure-area relationship of the collapsible segment of the pharynx in anesthetized pigs under the following three conditions: baseline (BL), RS induced by partial obstruction of the tracheostomy tube, and HG-ES. Parameters were obtained also after transection of the neck muscles and the trachea (NMT) and after additional bilateral HG transection (HGT). In addition, we measured the force produced by in situ isolated geniohyoid (GH) during RS and HG-ES. Intense RS was recognized by large negative intrathoracic pressures and triggered high phasic genioglossus and GH EMG activity. GH contraction produced during maximal RS less than a quarter of the force obtained during HG-ES. The major finding of the study was that RS and ES differed in the mechanism by which they stabilized the pharynx: RS lowered the pressure-area slope, i.e., reduced pharyngeal compliance (14.1 ± 2.9 to 9.2 ± 1.9 mm2/cmH2O, P < 0.01). HG-ES shifted the slope toward lower pressures, i.e., lowered the calculated extraluminal pressure (17.4 ± 5.8 to 9.2 ± 7.4 cmH2O, P < 0.01). Changes during RS and HG-ES were not affected by NMT, but the effect of RS decreased significantly after HGT. In conclusion, HG-ES and RS affect the pharyngeal site of collapse differently. Tongue muscle contraction contributes to pharyngeal stiffening during RS.
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Affiliation(s)
- A. Brodsky
- Otolaryngology Bnai Zion Medical Center, Haifa, Israel
| | - Y. Dotan
- Internal Medicine, Bnai Zion Medical Center, Haifa, Israel
| | - M. Samri
- Anesthesiology, Bnai Zion Medical Center, Haifa, Israel; and
| | - A. R. Schwartz
- Johns Hopkins Sleep Disorders Center, Baltimore, Maryland
| | - A. Oliven
- Internal Medicine, Bnai Zion Medical Center, Haifa, Israel
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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: 34] [Impact Index Per Article: 3.8] [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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15
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Abstract
Sleep disordered breathing is a common chronic condition in the general population. This review will highlight the prevalence of different types of sleep apnea in general and obstructive type in particular in the United States and Middle East. Despite the extensive research studies on the sleep apnea pathogenesis, the exact mechanism is not well known. Obesity, however, is the leading risk factor to upper airway narrowing and obstruction and main contributor to the escalating prevalence of morbidity worldwide including the Arab countries. Due to the serious consequences of the untreated sleep disordered breathing, this article will emphasize on the importance of early recognition, key clinical manifestations, and how to treat and prevent the disease.
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Affiliation(s)
- Abdul Ghani Sankri-Tarbichi
- Division of Pulmonary, Critical Care and Sleep Medicine, Wayne State University- School of Medicine, John D. Dingell VA Medical Center and Detroit Medical Center, Detroit, USA
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16
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Polotsky M, Elsayed-Ahmed AS, Pichard L, Harris CC, Smith PL, Schneider H, Kirkness JP, Polotsky V, Schwartz AR. Effects of leptin and obesity on the upper airway function. J Appl Physiol (1985) 2012; 112:1637-43. [PMID: 22345430 DOI: 10.1152/japplphysiol.01222.2011] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Obesity is associated with alterations in upper airway collapsibility during sleep. Obese, leptin-deficient mice demonstrate blunted ventilatory control, leading us to hypothesize that (1) obesity and leptin deficiency would predispose to worsening neuromechanical upper airway function and that (2) leptin replacement would acutely reverse neuromuscular defects in the absence of weight loss. In age-matched, anesthetized, spontaneously breathing C57BL/6J (BL6) and ob(-)/ob(-) mice, we characterized upper airway pressure-flow dynamics during ramp decreases in nasal pressure (P(N)) to determine the passive expiratory critical pressure (P(CRIT)) and active responses to reductions in P(N), including the percentage of ramps showing inspiratory flow limitation (IFL; frequency), the P(N) threshold at which IFL developed, maximum inspiratory airflow (Vi(max)), and genioglossus electromyographic (EMG(GG)) activity. Elevations in body weight were associated with progressive elevations in P(CRIT) (0.1 ± 0.02 cmH(2)O/g), independent of mouse strain. P(CRIT) was also elevated in ob(-)/ob(-) compared with BL6 mice (1.6 ± 0.1 cmH(2)O), independent of weight. Both obesity and leptin deficiency were associated with significantly higher IFL frequency and P(N) threshold and lower VI(max). Very obese ob(-)/ob(-) mice treated with leptin compared with nontreated mice showed a decrease in IFL frequency (from 63.5 ± 2.9 to 30.0 ± 8.6%) and P(N) threshold (from -0.8 ± 1.1 to -5.6 ± 0.8 cmH(2)O) and increase in VI(max) (from 354.1 ± 25.3 to 659.0 ± 71.8 μl/s). Nevertheless, passive P(CRIT) in leptin-treated mice did not differ significantly from that seen in nontreated ob(-)/ob(-) mice. The findings suggest that weight and leptin deficiency produced defects in upper airway neuromechanical control and that leptin reversed defects in active neuromuscular responses acutely without reducing mechanical loads.
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Affiliation(s)
- Mikhael Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
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Schwartz AR, Schneider H, Smith PL, McGinley BM, Patil SP, Kirkness JP. Physiologic phenotypes of sleep apnea pathogenesis. Am J Respir Crit Care Med 2012; 184:1105-6. [PMID: 22086988 DOI: 10.1164/rccm.201108-1573ed] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Cao Y, McGuire M, Liu C, Malhotra A, Ling L. Phasic respiratory modulation of pharyngeal collapsibility via neuromuscular mechanisms in rats. J Appl Physiol (1985) 2011; 112:695-703. [PMID: 22052868 DOI: 10.1152/japplphysiol.00136.2011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Obstructive sleep apnea patients experience recurrent upper airway (UA) collapse due to decreases in the UA dilator muscle activity during sleep. In contrast, activation of UA dilators reduces pharyngeal critical pressure (Pcrit, an index of pharyngeal collapsibility), suggesting an inverse relationship between pharyngeal collapsibility and dilator activity. Since most UA muscles display phasic respiratory activity, we hypothesized that pharyngeal collapsibility is modulated by respiratory drive via neuromuscular mechanisms. Adult male Sprague-Dawley rats were anesthetized, vagotomized, and ventilated (normocapnia). In one group, integrated genioglossal activity, Pcrit, and maximal airflow (V(max)) were measured at three expiration and five inspiration time points within the breathing cycle. Pcrit was closely and inversely related to phasic genioglossal activity, with the value measured at peak inspiration being the lowest. In other groups, the variables were measured during expiration and peak inspiration, before and after each of five manipulations. Pcrit was 26% more negative (-15.0 ± 1.0 cmH(2)O, -18.9 ± 1.2 cmH(2)O; n = 23), V(max) was 7% larger (31.0 ± 1.0 ml/s, 33.2 ± 1.1 ml/s), nasal resistance was 12% bigger [0.49 ± 0.05 cmH(2)O/(ml/s), 0.59 ± 0.05 cmH(2)O/(ml/s)], and latency to induced UA closure was 14% longer (55 ± 4 ms, 63 ± 5 ms) during peak inspiration vs. expiration (all P < 0.005). The expiration-inspiration difference in Pcrit was abolished with neuromuscular blockade, hypocapnic apnea, or death but was not reduced by the superior laryngeal nerve transection or altered by tracheal displacement. Collectively, these results suggest that pharyngeal collapsibility is moment-by-moment modulated by respiratory drive and this phasic modulation requires neuromuscular mechanisms, but not the UA negative pressure reflex or tracheal displacement by phasic lung inflation.
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Affiliation(s)
- Ying Cao
- Division of Sleep Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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19
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Polotsky M, Elsayed-Ahmed AS, Pichard L, Richardson RA, Smith PL, Schneider H, Kirkness JP, Polotsky V, Schwartz AR. Effect of age and weight on upper airway function in a mouse model. J Appl Physiol (1985) 2011; 111:696-703. [PMID: 21719728 DOI: 10.1152/japplphysiol.00123.2011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Defects in pharyngeal mechanical and neuromuscular control are required for the development of obstructive sleep apnea. Obesity and age are known sleep apnea risk factors, leading us to hypothesize that specific defects in upper airway neuromechanical control are associated with weight and age in a mouse model. In anesthetized, spontaneously breathing young and old wild-type C57BL/6J mice, genioglossus electromyographic activity (EMG(GG)) was monitored and upper airway pressure-flow dynamics were characterized during ramp decreases in nasal pressure (Pn, cmH₂O). Specific body weights were targeted by controlling caloric intake. The passive critical pressure (Pcrit) was derived from pressure-flow relationships during expiration. The Pn threshold at which inspiratory flow limitation (IFL) developed and tonic and phasic EMG(GG) activity during IFL were quantified to assess the phasic modulation of pharyngeal patency. The passive Pcrit increased progressively with increasing body weight and increased more in the old than young mice. Tonic EMG(GG) decreased and phasic EMG(GG) increased significantly with obesity. During ramp decreases in Pn, IFL developed at a higher (less negative) Pn threshold in the obese than lean mice, although the frequency of IFL decreased with age and weight. The findings suggest that weight imposes mechanical loads on the upper airway that are greater in the old than young mice. The susceptibility to upper airway obstruction increases with age and weight as tonic neuromuscular activity falls. IFL can elicit phasic responses in normal mice that mitigate or eliminate the obstruction altogether.
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Affiliation(s)
- Mikhael Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
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Sankri-Tarbichi AG, Richardson NN, Chowdhuri S, Rowley JA, Safwan Badr M. Hypocapnia is associated with increased upper airway expiratory resistance during sleep. Respir Physiol Neurobiol 2011; 177:108-13. [PMID: 21513820 DOI: 10.1016/j.resp.2011.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 03/28/2011] [Accepted: 04/05/2011] [Indexed: 10/18/2022]
Abstract
We hypothesized that hypocapnia is responsible for increased expiratory resistance during NREM sleep. Hypocapnia was induced by hypoxic hyperventilation in 21 subjects (aged 29.4 ± 7.8 yrs, 10 women, BMI 24.4 ± 4.3 kg/m(2)). Isocapnic hypoxia was induced in 12 subjects of whom, 6 underwent hypocapnic hypoxia in the same night. Upper airway resistance (R(UA)) was measured at the linear pressure-flow relationship during inspiration and expiration. Inspiratory flow limitation (IFL) was defined as the dissociation in pressure-flow relationship. (1) Expiratory R(UA) increased during hypocapnic but not isocapnic hypoxia relative to control (11.0 ± 5.6 vs. 8.2 ± 3.6 cm H(2)O/L/s; p < 0.05, and 11.45.0 vs. 10.94.4 cm H(2)O/L/s; p = NS, respectively). (2) No gender difference was found in R(UA) (p = NS). (3) Increased expiratory R(UA) correlated with the IFL change during hypocapnic but not isocapnic hypoxia. (4) No changes were noted in inspiratory R(UA) or IFL. Expiratory R(UA) increased during hypocapnia and was associated with IFL, indicating upper airway narrowing. Gender does not influence the upper airway response to hypocapnic hypoxia.
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Affiliation(s)
- Abdul Ghani Sankri-Tarbichi
- Sleep Research Laboratory, John D Dingell Veterans Affairs Medical Center, Division of Pulmonary, Allergy, Critical Care & Sleep, 3990 John R, 3-Hudson, Department of Internal Medicine, Wayne State University School, Detroit, MI, United States.
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21
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Sankri-Tarbichi AG, Rowley JA, Badr MS. Inhibition of ventilatory motor output increases expiratory retro palatal compliance during sleep. Respir Physiol Neurobiol 2011; 176:136-43. [PMID: 21334465 DOI: 10.1016/j.resp.2011.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 02/11/2011] [Accepted: 02/14/2011] [Indexed: 11/18/2022]
Abstract
UNLABELLED We hypothesized that inhibition of ventilatory motor output leads to increased pharyngeal compliance during NREM sleep, independent of lung volume. METHODS Eighteen subjects were studied using noninvasive positive pressure ventilation (NPPV) to inhibit ventilatory motor output during stable NREM sleep. Nasopharyngoscopy was used to measure the retro palatal cross-sectional area/pressure relationship (CSA/Pph) in 8 subjects. The effect of NPPV on neck circumference (NC) and end-expiratory lung volumes (EELV) was studied in 10 additional subjects using strain gauge plethysmography and respitrace, respectively. RESULTS (1) The CSA/Pph was increased during expiration under passive compared to active breathing (11.7 ± 7.1 vs. 8.5 ± 5.6mm(2)/cmH(2)O, respectively; p < 0.05) but not during inspiration. (2) NC correlated with the CSA/Pph during passive expiration (R(2) = 0.77, p < 0.05). (3) NC and EELV did not change between active and passive breaths (p = NS). CONCLUSIONS (1) Inhibiting the ventilatory motor output increases the pharyngeal compliance. (2) Increased passive expiratory pharyngeal compliance was not associated with changes in NC or EELV.
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Affiliation(s)
- Abdul Ghani Sankri-Tarbichi
- Wayne State University Sleep Research Laboratory, John D. Dingell Veterans Affairs Medical Center, 4646 John R, Detroit, MI 48201, USA.
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22
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Abstract
Sleep-induced apnea and disordered breathing refers to intermittent, cyclical cessations or reductions of airflow, with or without obstructions of the upper airway (OSA). In the presence of an anatomically compromised, collapsible airway, the sleep-induced loss of compensatory tonic input to the upper airway dilator muscle motor neurons leads to collapse of the pharyngeal airway. In turn, the ability of the sleeping subject to compensate for this airway obstruction will determine the degree of cycling of these events. Several of the classic neurotransmitters and a growing list of neuromodulators have now been identified that contribute to neurochemical regulation of pharyngeal motor neuron activity and airway patency. Limited progress has been made in developing pharmacotherapies with acceptable specificity for the treatment of sleep-induced airway obstruction. We review three types of major long-term sequelae to severe OSA that have been assessed in humans through use of continuous positive airway pressure (CPAP) treatment and in animal models via long-term intermittent hypoxemia (IH): 1) cardiovascular. The evidence is strongest to support daytime systemic hypertension as a consequence of severe OSA, with less conclusive effects on pulmonary hypertension, stroke, coronary artery disease, and cardiac arrhythmias. The underlying mechanisms mediating hypertension include enhanced chemoreceptor sensitivity causing excessive daytime sympathetic vasoconstrictor activity, combined with overproduction of superoxide ion and inflammatory effects on resistance vessels. 2) Insulin sensitivity and homeostasis of glucose regulation are negatively impacted by both intermittent hypoxemia and sleep disruption, but whether these influences of OSA are sufficient, independent of obesity, to contribute significantly to the "metabolic syndrome" remains unsettled. 3) Neurocognitive effects include daytime sleepiness and impaired memory and concentration. These effects reflect hypoxic-induced "neural injury." We discuss future research into understanding the pathophysiology of sleep apnea as a basis for uncovering newer forms of treatment of both the ventilatory disorder and its multiple sequelae.
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Affiliation(s)
- Jerome A Dempsey
- The John Rankin Laboratory of Pulmonary Medicine, Departments of Population Health Sciences and of Orthopedics and Rehabilitation, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin 53706, USA.
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Sankri-Tarbichi AG, Rowley JA, Badr MS. Expiratory pharyngeal narrowing during central hypocapnic hypopnea. Am J Respir Crit Care Med 2009; 179:313-9. [PMID: 19201929 PMCID: PMC2643080 DOI: 10.1164/rccm.200805-741oc] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 11/20/2008] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Ventilatory motor output is an important determinant of upper airway patency during sleep. OBJECTIVES We hypothesized that central hypocapnic hypopnea would lead to increased expiratory upper airway resistance and pharyngeal narrowing during non-REM sleep. METHODS Noninvasive positive pressure ventilation was used to induce hypocapnic hypopnea in 20 healthy subjects. Expiratory pressure was set at the lowest pressure (2 cm H(2)O), and inspiratory pressure was increased gradually during each 3-minute noninvasive positive pressure ventilation trial by increments of 2 cm H(2)O. Analysis 1 (n = 9) included measured retropalatal cross-sectional area (CSA) using nasopharyngoscope to compare CSA at five points of the respiratory cycle between control (eupneic) and hypopneic breaths. The pharyngeal pressure (P(ph)) was measured using a catheter positioned at the palatal rim. Analysis 2 (n = 11) included measured supraglottic pressure and airflow to compare inspiratory and expiratory upper airway resistance (R(UA)) at peak flow between eupneic and hypopneic breaths. MEASUREMENTS AND MAIN RESULTS Expiratory CSA during hypopneic breaths was decreased relative to eupnea (CSA at beginning of expiration [BI]: 101.5 +/- 6.3 vs. 121.6 +/- 8.9%; P < 0.05); P(ph)-BI was lower than that generated during eupnea (1.5 +/- 0.3 vs. 3.3 +/- 0.9 cm H(2)O; P < 0.05). Body mass index was an independent predictor of retropalatal narrowing during hypopnea. Hypopnea-R(UA) increased during expiration relative to eupnea (14.0 +/- 5.7 vs. 10.6 +/- 2.5 cm H(2)O/L/s; P = 0.01), with no change in inspiratory resistance. CONCLUSIONS Expiratory pharyngeal narrowing occurs during central hypocapnic hypopnea. Reduced ventilatory drive leads to increased expiratory, but not inspiratory, upper airway resistance. Central hypopneas are obstructive events because they cause pharyngeal narrowing.
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Affiliation(s)
- Abdul Ghani Sankri-Tarbichi
- Wayne State University Sleep Research Laboratory, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan, USA.
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24
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Farré R, Montserrat JM, Navajas D. Assessment of upper airway mechanics during sleep. Respir Physiol Neurobiol 2008; 163:74-81. [DOI: 10.1016/j.resp.2008.06.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2008] [Revised: 06/16/2008] [Accepted: 06/18/2008] [Indexed: 11/26/2022]
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25
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Fregosi RF. Influence of tongue muscle contraction and dynamic airway pressure on velopharyngeal volume in the rat. J Appl Physiol (1985) 2008; 104:682-93. [DOI: 10.1152/japplphysiol.01043.2007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mammalian pharynx is a collapsible tube that narrows during inspiration as transmural pressure becomes negative. The velopharynx (VP), which lies posterior to the soft palate, is considered to be one of the most collapsible pharyngeal regions. I tested the hypothesis that negative transmural pressure would narrow the VP, and that electrical stimulation of extrinsic tongue muscles would reverse this effect. Pressure (−6, −3, 3, and 6 cmH2O) was applied to the isolated pharyngeal airway of anesthetized rats that were positioned in a 4.7-T MRI scanner. The volume of eight axial slices encompassing the length of the VP was computed at each level of pressure, with and without bilateral hypoglossal nerve stimulation (0.1-ms pulse, one-third maximum force, 80 Hz). Negative pressure narrowed the VP, and either whole hypoglossal nerve stimulation (coactivation of protrudor and retractor muscles) or medial nerve branch stimulation (independent activation of tongue protrudor muscles) reversed this effect, with the greatest impact in the caudal one-third of the VP. The dilating effects of medial branch stimulation were slightly larger than whole nerve stimulation. Positive pressure dilated the VP, but tongue muscle contraction did not cause further dilation under these conditions. I conclude that the narrowest and most collapsible segment of the rat pharynx is in the caudal VP, posterior to the tip of the soft palate. Either coactivation of protrudor and retractor muscles or independent contraction of protrudor muscles caused dilation of this region, but the latter was slightly more effective.
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26
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Doherty LS, Cullen JP, Nolan P, McNicholas WT. The human genioglossus response to negative airway pressure: stimulus timing and route of delivery. Exp Physiol 2007; 93:288-95. [PMID: 17951328 DOI: 10.1113/expphysiol.2007.039677] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The genioglossus reflex response to sudden onset pulses of negative airway pressure (NAP) in humans is reported to occur more commonly at end rather than onset of expiration when delivered via a mouthpiece. We examined whether this response was modulated by the route of stimulus delivery throughout the respiratory cycle. The genioglossus surface EMG (GGsEMG) response to NAP delivered randomly throughout the respiratory cycle was measured in a set of experiments: (i) 40 stimuli of NAP at -5, -7.5 and -10 cmH2O applied to eight healthy, awake, supine males via nose-mask; and (ii) 60 stimuli of -7.5 cmH2O NAP applied to 15 subjects via both nose-mask and mouthpiece in random order. Despite similar pressure changes being detected in the epiglottis during both routes of stimulus delivery, far lower pressure changes were measured at the nasal choanae during mouthpiece compared with nose-mask delivery. There were no significant differences between the responses during any phase of respiration, nor when NAP was delivered via nose-mask or mouthpiece. We conclude that the sensitivity of the GGsEMG response to NAP in humans does not vary significantly with phase of respiration or route of breathing.
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Affiliation(s)
- Liam S Doherty
- Respiratory Sleep Disorders Unit, St. Vincent's University Hospital, Dublin, Ireland
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27
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Patil SP, Schneider H, Schwartz AR, Smith PL. Adult obstructive sleep apnea: pathophysiology and diagnosis. Chest 2007; 132:325-37. [PMID: 17625094 PMCID: PMC2813513 DOI: 10.1378/chest.07-0040] [Citation(s) in RCA: 317] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Obstructive sleep apnea (OSA) is a highly prevalent disease characterized by recurrent episodes of upper airway obstruction that result in recurrent arousals and episodic oxyhemoglobin desaturations during sleep. Significant clinical consequences of the disorder cover a wide spectrum, including daytime hypersomnolence, neurocognitive dysfunction, cardiovascular disease, metabolic dysfunction, and cor pulmonale. The major risk factors for the disorder include obesity, male gender, and age. Current understanding of the pathophysiologic basis of the disorder suggests that a balance of anatomically imposed mechanical loads and compensatory neuromuscular responses are important in maintaining upper airway patency during sleep. OSA develops in the presence of both elevated mechanical loads on the upper airway and defects in compensatory neuromuscular responses. A sleep history and physical examination is important in identification of patients and appropriate referral for polysomnography. Understanding nuances in the spectrum of presenting complaints and polysomnography correlates are important for diagnostic and therapeutic approaches. Knowledge of common patterns of OSA may help to identify patients and guide therapy.
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Affiliation(s)
- Susheel P Patil
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Baltimore, MD 21224, USA.
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28
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Kirkness JP, Schwartz AR, Patil SP, Pichard LE, Marx JJ, Smith PL, Schneider H. Dynamic modulation of upper airway function during sleep: a novel single-breath method. J Appl Physiol (1985) 2006; 101:1489-94. [PMID: 16825526 DOI: 10.1152/japplphysiol.00173.2006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To examine the dynamic modulation of upper airway (UA) function during sleep, we devised a novel approach to measuring the critical pressure (Pcrit) within a single breath in tracheostomized sleep apnea patients. We hypothesized that the UA continuously modulates airflow dynamics during transtracheal insufflation. In this study, we examine tidal pressure-flow relationships throughout the respiratory cycle to compare phasic differences in UA collapsibility between closure and reopening. Five apneic subjects (with tracheostomy) were recruited (2 men, 3 women; 18–50 yr; 20–35 kg/m2; apnea-hypopnea index >20) for this polysomnographic study. Outgoing airflow through the UA (face mask pneumotachograph) and tracheal pressure were recorded during brief transtracheal administration of insufflated airflow via a catheter. Pressure-flow relationships were generated from deflation (approaching Pcrit) and inflation (after Pcrit) of the UA during non-rapid eye movement sleep. During each breath, UA function was described by a pressure-flow relationship that defined the collapsibility (Pcrit) and upstream resistance (Rus). UA characteristics were examined in the presence and absence of complete UA occlusion. We demonstrated that Pcrit and Rus changed dynamically throughout the respiratory cycle. The UA closing pressure (4.4 ± 2.0 cmH2O) was significantly lower than the opening pressure (10.8 ± 2.4 cmH2O). Rus was higher for deflation (18.1 ± 2.4 cmH2O·l−1·s) than during inflation (7.5 ± 1.9 cmH2O·l−1·s) of the UA. Preventing occlusion decreases UA pressure-flow loop hysteresis by ∼4 cmH2O. These findings indicate that UA collapsibility varies dynamically throughout the respiratory cycle and that both local mechanical and neuromuscular factors may be responsible for this dynamic modulation of UA function during sleep.
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Abstract
The pathogenesis of obstructive sleep apnea (OSA) has been under investigation for over 25 years, during which a number of factors that contribute to upper airway (UA) collapse during sleep have been identified. Structural/anatomic factors that constrict space for the soft tissues surrounding the pharynx and its lumen are crucial to the development of OSA in many patients. Enlargement of soft tissues enveloping the pharynx, including hypertrophied tonsils, adenoids, and tongue, is also an important factor predisposing to UA collapse, inasmuch as this can impinge on the pharyngeal lumen and narrow it during sleep. Other factors, including impairment of UA mechanoreceptor sensitivity and reflexes that maintain pharyngeal patency and respiratory control system instability, have also been identified as possible mechanisms facilitating UA instability. This suggests that OSA may be a heterogeneous disorder, rather than a single disease entity. Therefore, the extent to which various pathogenic factors contribute to the phenomenon of repetitive collapse of the UA during sleep probably varies from patient to patient. Further elucidation of specific pathogenic mechanisms in individuals with OSA may facilitate the development of new therapies that can be tailored to individual patient needs according to the underlying mechanism(s) of their disease.
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Affiliation(s)
- Clodagh M Ryan
- Sleep Research Laboratory of Toronto Rehabilitation Institute, Toronto General Hospital/University Health Network, ON, Canada
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Gourcerol G, Marie JP, Verin E. Glottis constriction response in healthy subjects. Respir Physiol Neurobiol 2005; 148:303-8. [PMID: 16143286 DOI: 10.1016/j.resp.2005.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Revised: 02/09/2005] [Accepted: 02/10/2005] [Indexed: 10/25/2022]
Abstract
The purpose of this study was to evaluate the glottis constriction response induced by a sudden and involuntary increase in gastric and oesophageal pressures by Tll-Ll intervertebral magnetic stimulation of the abdominal muscle roots in nine healthy subjects. Twitch flow, twitch gastric, and oesophageal pressures were measured after abdominal muscle root stimulation, which allowed pharyngo-laryngeal muscle activation to be characterized. Pharyngeal endoscopies were performed on five subjects to assess vocal cord movements. All stimulations induced positive gastric and oesophageal pressures and expiratory flow, which increased with stimulation intensity (flow: R=0.32; p<0.0001; oesophageal pressure: R=0.26; p=0.001; gastric pressure: R=0.37; p<0.0001). Twitch gastric pressure and twitch oesophageal pressure were negatively correlated with twitch flow (respectively, R=-0.183, p<0.05; R=-0.35, p<0.0001). Upper airway resistance was higher at peak oesophageal pressure than at peak flow (p<0.001). Peak twitch gastric and twitch oesophageal pressure latencies were similar (133+/-4ms and 122+/-4ms) but longer than peak twitch flow and EMG latencies (62+/-2ms and 73+/-4ms, p<0.0001). Glottis constriction following magnetic abdominal muscle root stimulation was seen in all subjects during endoscopy, with a latency estimated at between 80 and 100ms. This method could be a new, simple tool for assessing the upper airway constriction protective reflex.
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Affiliation(s)
- Guillaume Gourcerol
- Service de Physiologie Digestive, Urinaire, Respiratoire et Sportive, Hôpital Charles Nicolle, CHU de Rouen, 1 rue de Germont, 76031 Rouen Cedex, France
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31
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Farré R, Rigau J, Montserrat JM, Buscemi L, Ballester E, Navajas D. Static and dynamic upper airway obstruction in sleep apnea: role of the breathing gas properties. Am J Respir Crit Care Med 2003; 168:659-63. [PMID: 12869358 DOI: 10.1164/rccm.200211-1304oc] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Increased upper airway collapsibility in the sleep apnea/hypopnea syndrome (SAHS) is usually interpreted by a collapsible resistor model characterized by a critical pressure (Pcrit) and an upstream resistance (Rup). To investigate the role played by the upstream segment of the upper airway, we tested the hypothesis that breathing different gases would modify Rup but not Pcrit. The study was performed on 10 patients with severe SAHS (apnea-hypopnea index: 59 +/- 14 events/hour) when breathing air and helium-oxygen (He-O2) during non-REM sleep. The continuous positive airway pressure that normalized flow (CPAPopt) was measured. Rup and Pcrit were determined from the linear relationship between maximal inspiratory flow VImax and nasal pressure (PN):VImax = (PN - Pcrit)/Rup. Changing the breathing gas selectively modified the severity of dynamic (CPAPopt, Rup) and static (Pcrit) obstructions. CPAPopt was significantly (p = 0.0013) lower when breathing He-O2 (8.44 +/- 1.66 cm H2O; mean +/- SD) than air (10.18 +/- 2.34 cm H2O). Rup was markedly lower (p = 0.0001) when breathing He-O2 (9.21 +/- 3.93 cm H2O x s/L) than air (15.92 +/- 6.27 cm H2O x s/L). Pcrit was similar (p = 0.039) when breathing He-O2 (4.89 +/- 2.37 cm H2O) and air (4.19 +/- 2.93 cm H2O). The data demonstrate the role played by the upstream segment of the upper airway and suggest that different mechanisms determine static (Pcrit) and dynamic (Rup) upper airway obstructions in SAHS.
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Affiliation(s)
- Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, Spain.
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Schneider H, Patil SP, Canisius S, Gladmon EA, Schwartz AR, O'Donnell CP, Smith PL, Tankersley CG. Hypercapnic duty cycle is an intermediate physiological phenotype linked to mouse chromosome 5. J Appl Physiol (1985) 2003; 95:11-9. [PMID: 12794091 DOI: 10.1152/japplphysiol.01144.2002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We hypothesized that upper airway obstruction (UAO) leads to a compensatory increase in the duty cycle [ratio of inspiratory time to respiratory cycle length (Ti/Tt)], which is determined by genetic factors. We examined the compensatory Ti/Tt responses to 1). UAO and hypercapnia among normal individuals and 2). hypercapnia in different inbred strains, C3H/HeJ (C3) and C57BL/6J (B6), and their first- and second-generation (F2) offspring. 3). We then used the compensatory Ti/Tt response in the F2 to determine genetic linkage to the mouse genome. First, normal individuals exhibited a similar increase in the Ti/Tt during periods of hypercapnia (0.11 +/- 0.07) and UAO (0.09 +/- 0.06) compared with unobstructed breathing (P < 0.01). Second, the F2 offspring of C3 and B6 progenitors showed an average Ti/Tt response to 3% CO2 (0.42 +/- 0.005%) that was significantly (P < 0.01) greater than that of the two progenitors. Third, with a peak log of the odds ratio score of 4.4, Ti/Tt responses of F2 offspring are genetically linked to an interval between 58 and 64 centimorgans (cM) on mouse chromosome 5. One gene in the interval, Dagk4 at 57 cM, is polymorphic for C3 and B6 mice. Two other genes, Adrbk2 at 60 cM and Nos1 at 65 cM, have biological plausibility in mechanisms of upper airway patency and chemosensitivity, respectively. In summary, Ti/Tt may serve as an intermediate physiological phenotype for compensatory neuromuscular response mechanisms for maintaining ventilation in the face of UAO and hypoventilation and to help target specific candidate genes that may play a role in the expression of sleep-disordered breathing.
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Affiliation(s)
- H Schneider
- Johns Hopkins Sleep Disorder, Division of Pulmonary and Critical Care Medicine, John Hopkins University School of Medicine, Baltimore, MD 21224, USA.
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