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Vena D, Gell L, Messineo L, Mann D, Azarbarzin A, Calianese N, Wang TY, Yang H, Alex R, Labarca G, Hu WH, Sumner J, White DP, Wellman A, Sands SA. Physiological Determinants of Snore Loudness. Ann Am Thorac Soc 2024; 21:114-121. [PMID: 37879037 PMCID: PMC10867912 DOI: 10.1513/annalsats.202305-438oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 10/24/2023] [Indexed: 10/27/2023] Open
Abstract
Rationale: The physiological factors modulating the severity of snoring have not been adequately described. Airway collapse or obstruction is generally the leading determinant of snore sound generation; however, we suspect that ventilatory drive is of equal importance. Objective: To determine the relationship between airway obstruction and ventilatory drive on snore loudness. Methods: In 40 patients with suspected or diagnosed obstructive sleep apnea (1-98 events/hr), airflow was recorded via a pneumotachometer attached to an oronasal mask, ventilatory drive was recorded using calibrated intraesophageal diaphragm electromyography, and snore loudness was recorded using a calibrated microphone attached over the trachea. "Obstruction" was taken as the ratio of ventilation to ventilatory drive and termed flow:drive, i.e., actual ventilation as a percentage of intended ventilation. Lower values reflect increased flow resistance. Using 165,063 breaths, mixed model analysis (quadratic regression) quantified snore loudness as a function of obstruction, ventilatory drive, and the presence of extreme obstruction (i.e., apneic occlusion). Results: In the presence of obstruction (flow:drive = 50%, i.e., doubled resistance), snore loudness increased markedly with increased drive (+3.4 [95% confidence interval, 3.3-3.5] dB per standard deviation [SD] change in ventilatory drive). However, the effect of drive was profoundly attenuated without obstruction (at flow:drive = 100%: +0.23 [0.08-0.39] dB per SD change in drive). Similarly, snore loudness increased with increasing obstruction exclusively in the presence of increased drive (at drive = 200% of eupnea: +2.1 [2.0-2.2] dB per SD change in obstruction; at eupneic drive: +0.14 [-0.08 to 0.28] dB per SD change). Further, snore loudness decreased substantially with extreme obstruction, defined as flow:drive <20% (-9.9 [-3.3 to -6.6] dB vs. unobstructed eupneic breathing). Conclusions: This study highlights that ventilatory drive, and not simply pharyngeal obstruction, modulates snore loudness. This new framework for characterizing the severity of snoring helps better understand the physiology of snoring and is important for the development of technologies that use snore sounds to characterize sleep-disordered breathing.
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Affiliation(s)
- Daniel Vena
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Laura Gell
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ludovico Messineo
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Dwayne Mann
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Queensland, Australia; and
| | - Ali Azarbarzin
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Nicole Calianese
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Tsai-Yu Wang
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Hyungchae Yang
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
- Department of Otorhinolaryngology–Head and Neck Surgery, Chonnam National University Medical School, Gwangju, Korea
| | - Raichel Alex
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Gonzalo Labarca
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Wen-Hsin Hu
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jeffrey Sumner
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - David P. White
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Andrew Wellman
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Scott A. Sands
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
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Luo YM, Chen YY, Liang SF, Wu LG, Wellman A, McEvoy RD, Steier J, Eckert DJ, Polkey MI. Central sleep apnea treated by a constant low-dose CO 2 supplied by a novel device. J Appl Physiol (1985) 2023; 135:977-984. [PMID: 37675475 DOI: 10.1152/japplphysiol.00312.2023] [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: 05/15/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 09/08/2023] Open
Abstract
CO2 inhalation has been previously reported as a treatment for central sleep apnea both when associated with heart failure or where the cause is unknown. Here, we evaluated a novel CO2 supply system using a novel open mask capable of comfortably delivering a constantly inspired fraction of CO2 ([Formula: see text]) during sleep. We recruited 18 patients with central sleep apnea (13 patients with cardiac disease, and 5 patients idiopathic) diagnosed by diaphragm electromyogram (EMG) recordings made during overnight full polysomnography (PSG) (night 1). In each case, the optimal [Formula: see text] was determined by an overnight manual titration with PSG (night 2). Titration commenced at 1% CO2 and increased by 0.2% increments until central sleep apnea (CSA) disappeared. Patients were then treated on the third night (night 3) with the lowest therapeutically effective concentration of CO2 derived from night 2. Comparing night 1 and night 3, both apnea-hypopnea index (AHI; 31 ± 14 vs. 6 ± 3 events/h, P < 0.01) and arousal index (22 ± 8 vs. 15 ± 8 events/h, P < 0.01) were significantly improved during CO2 treatment. Sleep efficiency improved from 71 ± 18 to 80 ± 11%, P < 0.05, and sleep latency was shorter (23 ± 18 vs. 10 ± 10 min, P < 0.01). Heart rate was not different between night 1 and night 3. Our data confirm the feasibility of our CO2 delivery system and indicate that individually titrated CO2 supplementation with a novel device including a special open mask can reduce sleep disordered breathing severity and improve sleep quality. Randomized controlled studies should now be undertaken to assess therapeutic benefit for patients with CSA.NEW & NOTEWORTHY A novel device using a special mask was developed and proved that CO2 therapy using the device could eliminate central sleep apnea (CSA) events and improve sleep quality including reducing arousal index in patients with heart failure. The device would become a useful clinical treatment for heart failure patients with CSA.
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Affiliation(s)
- Yuan-Ming Luo
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, People's Republic of China
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States
- College of Medicine and Public Health, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia
| | - Yong-Yi Chen
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, People's Republic of China
| | - Shan-Feng Liang
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, People's Republic of China
| | - Lu-Guang Wu
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, People's Republic of China
| | - Andrew Wellman
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States
| | - R Doug McEvoy
- College of Medicine and Public Health, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia
| | - Joerg Steier
- Lane Fox Respiratory Unit/Sleep Disorders Centre, London, United Kingdom
| | - Danny J Eckert
- College of Medicine and Public Health, Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia
| | - Michael I Polkey
- Royal Brompton Hospital, Guy's and St. Thomas' NHS Foundation Trust, London, United Kingdom
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3
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Lin L, Wang P, Zheng H, Zhong Z, Zhuansun Y, Yang Z, Chen R. RESPIRATORY MECHANICS AND NEURAL RESPIRATORY DRIVE OF UNTREATED GASPING DURING CARDIAC ARREST IN A PORCINE MODEL. Shock 2023; 59:948-954. [PMID: 37018832 DOI: 10.1097/shk.0000000000002127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
ABSTRACT Introduction: Although the effects on hemodynamics of gasping during cardiac arrest (CA) have received a lot of attention, less is known about the respiratory mechanics and physiology of respiration in gasping. This study aimed to investigate the respiratory mechanics and neural respiratory drive of gasping during CA in a porcine model. Method: Pigs weighing 34.9 ± 5.7 kg were anesthetized intravenously. Ventricular fibrillation (VF) was electrically induced and untreated for 10 min. Mechanical ventilation (MV) was ceased immediately after the onset of VF. Hemodynamic and respiratory parameters, pressure signals, diaphragmatic electromyogram data, and blood gas analysis data were recorded. Results: Gasping was observed in all the animals at a significantly lower rate (2-5 gaps/min), with higher tidal volume ( VT ; 0.62 ± 0.19 L, P < 0.01), and with lower expired minute volume (2.51 ± 1.49 L/min, P < 0.001) in comparison with the baseline. The total respiratory cycle time and the expiratory time tended to be lengthened. Statistically significant elevations in transdiaphragmatic pressure, the pressure-time product of diaphragmatic pressure, and the mean of root mean square diaphragmatic electromyogram values (RMSmean) were observed ( P < 0.05, P < 0.05, and P < 0.001, respectively); however, VT /RMSmean and transdiaphragmatic pressure/RMSmean were reduced at all time points. The partial pressure of oxygen showed a continuous decline after VF to reach statistical significance in the 10th minute (9.46 ± 0.96 kPa, P < 0.001), whereas the partial pressure of carbon dioxide tended to first rise and then fall. Conclusions: Gasping during CA was characterized by high VT , extremely low frequency, and prolonged expiratory time, which may improve hypercapnia. During gasping, increased work of breathing and insufficient neuromechanical efficacy of neural respiratory drive suggested the necessity of MV and appropriate management strategies for MV during resuscitation after CA.
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Affiliation(s)
- Lin Lin
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou
| | - Pengfei Wang
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou
| | | | - Zheye Zhong
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou
| | - Yongxun Zhuansun
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou
| | - Zhengfei Yang
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou
| | - Rui Chen
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou
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4
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McCartney A, Phillips D, James M, Chan O, Neder JA, de-Torres JP, Domnik NJ, Crinion SJ. Ventilatory neural drive in chronically hypercapnic patients with COPD: effects of sleep and nocturnal noninvasive ventilation. Eur Respir Rev 2022; 31:31/165/220069. [PMID: 36130786 DOI: 10.1183/16000617.0069-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/29/2022] [Indexed: 11/05/2022] Open
Abstract
Sleep brings major challenges for the control of ventilation in humans, particularly the regulation of arterial carbon dioxide pressure (P aCO2 ). In patients with COPD, chronic hypercapnia is associated with increased mortality. Therefore, nocturnal high-level noninvasive positive-pressure ventilation (NIV) is recommended with the intention to reduce P aCO2 down to normocapnia. However, the long-term physiological consequences of P aCO2 "correction" on the mechanics of breathing, gas exchange efficiency and resulting symptoms (i.e. dyspnoea) remain poorly understood. Investigating the influence of sleep on the neural drive to breathe and its translation to the mechanical act of breathing is of foremost relevance to create a solid rationale for the use of nocturnal NIV. In this review, we critically discuss the mechanisms by which sleep influences ventilatory neural drive and mechanical consequences in healthy subjects and hypercapnic patients with advanced COPD. We then discuss the available literature on the effects of nocturnal NIV on ventilatory neural drive and respiratory mechanics, highlighting open avenues for further investigation.
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Affiliation(s)
| | - Devin Phillips
- Dept of Medicine, Queen's University, Kingston, ON, Canada
| | - Matthew James
- Dept of Medicine, Queen's University, Kingston, ON, Canada
| | - Olivia Chan
- Dept of Medicine, Queen's University, Kingston, ON, Canada
| | - J Alberto Neder
- Dept of Medicine, Queen's University, Kingston, ON, Canada.,Division of Respirology and Sleep Medicine, Kingston Health Sciences Centre, Kingston, ON, Canada
| | - Juan P de-Torres
- Dept of Medicine, Queen's University, Kingston, ON, Canada.,Division of Respirology and Sleep Medicine, Kingston Health Sciences Centre, Kingston, ON, Canada
| | - Nicolle J Domnik
- Dept of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Sophie J Crinion
- Dept of Medicine, Queen's University, Kingston, ON, Canada .,Division of Respirology and Sleep Medicine, Kingston Health Sciences Centre, Kingston, ON, Canada
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5
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Gell LK, Vena D, Alex RM, Azarbarzin A, Calianese N, Hess LB, Taranto-Montemurro L, White DP, Wellman A, Sands SA. Neural ventilatory drive decline as a predominant mechanism of obstructive sleep apnoea events. Thorax 2022; 77:707-716. [PMID: 35064045 PMCID: PMC10039972 DOI: 10.1136/thoraxjnl-2021-217756] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 10/18/2021] [Indexed: 01/19/2023]
Abstract
BACKGROUND In the classic model of obstructive sleep apnoea (OSA), respiratory events occur with sleep-related dilator muscle hypotonia, precipitating increased neural ventilatory 'drive'. By contrast, a drive-dependent model has been proposed, whereby falling drive promotes dilator muscle hypotonia to precipitate respiratory events. Here we determine the extent to which the classic versus drive-dependent models of OSA are best supported by direct physiological measurements. METHODS In 50 OSA patients (5-91 events/hour), we recorded ventilation ('flow', oronasal mask and pneumotach) and ventilatory drive (calibrated intraoesophageal diaphragm electromyography, EMG) overnight. Flow and drive during events were ensemble averaged; patients were classified as drive dependent if flow fell/rose simultaneously with drive. Overnight effects of lower drive on flow, genioglossus muscle activity (EMGgg) and event risk were quantified (mixed models). RESULTS On average, ventilatory drive fell (rather than rose) during events (-20 (-42 to 3)%baseline, median (IQR)) and was strongly correlated with flow (R=0.78 (0.24 to 0.94)). Most patients (30/50, 60%) were classified as exhibiting drive-dependent event pathophysiology. Lower drive during sleep was associated with lower flow (-17 (-20 to -14)%/drive) and EMGgg (-3.5 (-3.8 to -3.3)%max/drive) and greater event risk (OR: 2.2 (1.8 to 2.5) per drive reduction of 100%eupnoea); associations were concentrated in patients with drive-dependent OSA (ie, flow: -37 (-40 to -34)%/drive, OR: 6.8 (5.3 to 8.7)). Oesophageal pressure-without tidal volume correction-falsely suggested rising drive during events (classic model). CONCLUSIONS In contrast to the prevailing view, patients with OSA predominantly exhibit drive-dependent event pathophysiology, whereby flow is lowest at nadir drive, and lower drive raises event risk. Preventing ventilatory drive decline is therefore considered a target for OSA intervention.
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Affiliation(s)
- Laura K Gell
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Daniel Vena
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Raichel M Alex
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Ali Azarbarzin
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Nicole Calianese
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Lauren B Hess
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Luigi Taranto-Montemurro
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - David P White
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Andrew Wellman
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Scott A Sands
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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6
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Luo YM, Polkey MI. Being obstructive in sleep apnoea: more of a drive than a load problem? Thorax 2022; 77:640. [DOI: 10.1136/thoraxjnl-2021-218437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2021] [Indexed: 11/03/2022]
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7
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Dempsey JA, Neder JA, Phillips DB, O'Donnell DE. The physiology and pathophysiology of exercise hyperpnea. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:201-232. [PMID: 35965027 DOI: 10.1016/b978-0-323-91534-2.00001-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In health, the near-eucapnic, highly efficient hyperpnea during mild-to-moderate intensity exercise is driven by three obligatory contributions, namely, feedforward central command from supra-medullary locomotor centers, feedback from limb muscle afferents, and respiratory CO2 exchange (V̇CO2). Inhibiting each of these stimuli during exercise elicits a reduction in hyperpnea even in the continuing presence of the other major stimuli. However, the relative contribution of each stimulus to the hyperpnea remains unknown as does the means by which V̇CO2 is sensed. Mediation of the hyperventilatory response to exercise in health is attributed to the multiple feedback and feedforward stimuli resulting from muscle fatigue. In patients with COPD, diaphragm EMG amplitude and its relation to ventilatory output are used to decipher mechanisms underlying the patients' abnormal ventilatory responses, dynamic lung hyperinflation and dyspnea during exercise. Key contributions to these exercise-limiting responses across the spectrum of COPD severity include high dead space ventilation, an excessive neural drive to breathe and highly fatigable limb muscles, together with mechanical constraints on ventilation. Major controversies concerning control of exercise hyperpnea are discussed along with the need for innovative research to uncover the link of metabolism to breathing in health and disease.
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Affiliation(s)
- Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, Department of Population Health Sciences, University of Wisconsin-Madison, Madison, WI, United States.
| | - J Alberto Neder
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre Kingston General Hospital Campus, Kingston, ON, Canada
| | - Devin B Phillips
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre Kingston General Hospital Campus, Kingston, ON, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre Kingston General Hospital Campus, Kingston, ON, Canada
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8
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Tolbert TM, Parekh A, Sands SA, Mooney AM, Ayappa I, Rapoport DM. Quantification of airway conductance from noninvasive ventilatory drive in patients with sleep apnea. J Appl Physiol (1985) 2021; 131:1640-1652. [PMID: 34498947 PMCID: PMC8616604 DOI: 10.1152/japplphysiol.00387.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/18/2021] [Accepted: 09/08/2021] [Indexed: 11/22/2022] Open
Abstract
Upper airway conductance, the ratio of inspiratory airflow to inspiratory effort, quantifies the degree of airway obstruction in hypopneas observed in sleep apnea. We evaluated the ratio of ventilation to noninvasive ventilatory drive as a surrogate of conductance. Furthermore, we developed and tested a refinement of noninvasive drive to incorporate the interactions of inspiratory flow, pressure, and drive to better estimate conductance. Hypopneas were compiled from existing polysomnography studies with esophageal catheterization in 18 patients with known or suspected sleep apnea, totaling 1,517 hypopneas during NREM sleep. For each hypopnea, reference standard conductance was calculated as the ratio of peak inspiratory flow to esophageal pressure change during inspiration. Ventilatory drive was calculated using the algorithm developed by Terrill et al. and then mathematically modified according to the presence or absence of flow limitation to noninvasively estimate esophageal pressure. The ratio of ventilation to ventilatory drive and the ratio of peak inspiratory flow to estimated esophageal pressure were each compared with the reference standard for all hypopneas and for median values from individual patients. Hypopnea ventilation to drive ratios were of limited correlation with the reference standard (R2 = 0.17, individual hypopneas; R2 = 0.03, median patient values). Modification of drive to estimated pressure yielded estimated conductance, which strongly correlated with reference standard conductance (R2 = 0.49, individual hypopneas; R2 = 0.77, median patient values). We conclude that the severity of airway obstruction during hypopneas may be estimated from noninvasive drive by accounting for mechanical effects of flow on pressure. NEW & NOTEWORTHY Classification of hypopneas as obstructive (decreased upper airway conductance) or central (decreased inspiratory flow commensurate with decreased effort) is complicated by the requirement of invasive methods, such as esophageal manometry. Here, we demonstrate that using a few esophageal pressure measurements to account for the interactions between inspiratory flow, pressure, and noninvasive ventilatory drive allows estimation of upper airway conductance. Further studies may use these findings to quantify airway obstruction completely noninvasively.
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Affiliation(s)
- Thomas M Tolbert
- Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Ankit Parekh
- Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Scott A Sands
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
- Department of Medicine, Monash University, Clayton, Victoria, Australia
| | - Anne M Mooney
- Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Indu Ayappa
- Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
| | - David M Rapoport
- Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, New York
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9
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Gell LK, Stadler DL, Reynolds KJ, Catcheside PG. Exaggerated ventilatory drive estimates from epiglottic and esophageal pressure deflections in the presence of airway occlusion. J Appl Physiol (1985) 2021; 131:760-767. [PMID: 34197224 DOI: 10.1152/japplphysiol.00896.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Esophageal and epiglottic pressure deflections are widely used to quantify ventilatory effort during sleep in patients with obstructive sleep apnea (OSA). However, changes in upper airway patency will fundamentally alter pressure gradients across the respiratory system with different airflow and volume-dependent effects on esophageal versus epiglottic pressure. The magnitude of these obstruction effects on ventilatory effort assessed from pressure deflections has not been systematically investigated. This study sought to quantify the direct effect of airway occlusion on esophageal and epiglottic pressure deflections during sleep in patients with OSA compared with predictions based on classic respiratory mechanics. Pneumotachograph airflow and volume, and esophageal, epiglottic, mask, and gastric pressures were measured throughout a nonoccluded breath before and the first occluded breath after repeated external airway occlusions during sleep in 13 patients with OSA on constant positive airway pressure (CPAP). Inspiratory pressure deflections were approximately doubled with epiglottic pressure, and increased by around 40% with esophageal pressure on the occluded compared with the preoccluded breath. Differences in pressure between pre- and occluded breaths showed strong dependence on volume and flow, in line with theoretical models of respiratory mechanics. A relatively simple correction factor could account for these effects to provide more consistent measures of ventilatory effort from pressure, independent from measurement site and changing airflow conditions. These finding have important implications for interpreting ventilatory effort and arousal threshold measurements and for understanding the relationships between underlying ventilatory drive and pressure deflections in the presence of airway obstruction during sleep.NEW & NOTEWORTHY Esophageal and epiglottic pressure deflection measurements are widely used as gold-standard measures of ventilatory effort without consideration of differential obstruction effects between measurement sites. This study is the first to quantify the effect of airway occlusion on pressure recordings during sleep. The findings of substantial acute effects of occlusion itself on pressure deflections are important to consider in the planning, analysis, and interpretation of studies that make inferences regarding inspiratory effort.
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Affiliation(s)
- Laura K Gell
- The Medical Device Research Institute, College of Science and Engineering, Flinders University of South Australia, Bedford Park, South Australia, Australia.,The Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University of South Australia, Bedford Park, South Australia, Australia
| | - Daniel L Stadler
- The Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University of South Australia, Bedford Park, South Australia, Australia
| | - Karen J Reynolds
- The Medical Device Research Institute, College of Science and Engineering, Flinders University of South Australia, Bedford Park, South Australia, Australia
| | - Peter G Catcheside
- The Medical Device Research Institute, College of Science and Engineering, Flinders University of South Australia, Bedford Park, South Australia, Australia.,The Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University of South Australia, Bedford Park, South Australia, Australia
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10
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Novel method for evaluating the upper airway resistance using the ratio of neural respiratory drive to flow in OSA. Sleep Med 2020; 73:162-169. [PMID: 32836084 DOI: 10.1016/j.sleep.2020.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 04/15/2020] [Accepted: 05/04/2020] [Indexed: 11/21/2022]
Abstract
STUDY OBJECTIVES Sleep is associated with a reduction in ventilation and an increase in upper airway resistance (UAR) in patients with obstructive sleep apnea (OSA). However, there is no consensus on the standard for assessment of UAR and therefore it is important to develop a method to reliably assess UAR in patients with OSA. The purpose of the present study is to determine whether the ratio of neural respiratory drive (NRD) to flow can be used to assess changes in UAR in OSA during sleep. METHODS A total of 24 patients (21 men) with OSA and 10 normal subjects (6 males) were studied. The UAR was assessed by the ratio of NRD to flow, which measured by esophageal pressure (Poes), diaphragm electromyography (EMGdi) and superficial diaphragm electromyography (SEMGdi) in various stages including wakefulness, N2 sleep, N2 sleep with snoring, hypopneas, the in the "preapnea" states in OSA versus wakefulness, sleeponset, N2 sleep, N3 sleep in normal subjects. All subjects underwent overnight full polysomnography using standard techniques. RESULTS Our study indicate that UAR was progressively higher from wakefulness to N2 sleep, N2 sleep with snoring, hypopneas, and the in the "preapnea" states in patients with OSA and had obvious difference in statistical significance (p < 0.05). We found NRD in hypopneas was lower than that in N2-snoring while the UAR in hypopneas was higher than that in N2-snoring.The UAR and NRD increased consecutively from wakefulness to N2 sleep and N3 sleep in normal subjects while the ventilation was reduced consecutively in NREM sleep. CONCLUSIONS It is feasible to use the ratio of neural respiratory drive to flow to assess UAR in patients with OSA during sleep.
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11
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Nguyen DAT, Amirjani N, McCaughey EJ, Gandevia SC, Butler JE, Hudson AL. Differential activation of the human costal and crural diaphragm during voluntary and involuntary breaths. J Appl Physiol (1985) 2020; 128:1262-1270. [DOI: 10.1152/japplphysiol.00790.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Simultaneous electromyographic recordings from the human costal and crural diaphragm during voluntary augmented breathing and involuntary rebreathing show that the increase in inspiratory crural diaphragm activity was ~60% of the increase in costal diaphragm activity. However costal to crural diaphragm activation did not differ between the two tasks. The dissociation in the amplitude of activation of the costal and crural diaphragm becomes apparent only as the drive to breathe increases above tidal breathing.
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Affiliation(s)
- D. A. T. Nguyen
- Neuroscience Research Australia, and University of New South Wales, Sydney, New South Wales, Australia
| | - N. Amirjani
- Neuroscience Research Australia, and University of New South Wales, Sydney, New South Wales, Australia
- Northern Alberta EMG and Neuromuscular Clinic, Alberta, Canada
| | - E. J. McCaughey
- Neuroscience Research Australia, and University of New South Wales, Sydney, New South Wales, Australia
| | - S. C. Gandevia
- Neuroscience Research Australia, and University of New South Wales, Sydney, New South Wales, Australia
- Prince of Wales Hospital, Randwick, New South Wales, Australia
| | - J. E. Butler
- Neuroscience Research Australia, and University of New South Wales, Sydney, New South Wales, Australia
| | - A. L. Hudson
- Neuroscience Research Australia, and University of New South Wales, Sydney, New South Wales, Australia
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12
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Bosi M, De Vito A, Eckert D, Steier J, Kotecha B, Vicini C, Poletti V. Qualitative Phenotyping of Obstructive Sleep Apnea and Its Clinical Usefulness for the Sleep Specialist. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17062058. [PMID: 32244892 PMCID: PMC7143772 DOI: 10.3390/ijerph17062058] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/12/2020] [Accepted: 03/17/2020] [Indexed: 12/12/2022]
Abstract
INTRODUCTION The anatomical collapsibility of the upper airway, neuromuscular tone and function, sleep-wake and ventilatory control instability, and the arousal threshold all interact and contribute to certain pathophysiologic features that characterize different types of obstructive sleep apnea (OSA). A model of qualitative phenotypizationallowsus to characterize the different pathophysiological traits in OSA patients. METHODS A narrative review was performed, to analyze the available literature evidence, with the purpose of generating a model of qualitative phenotypization to characterize pathophysiological traits in patients with OSA. RESULTS 96 out of 3829 abstracts were selected for full-text review. Qualitative phenotyping model of OSA:Data concerning the OSA qualitative pathophysiological traits' measurement can be deducted by means of clinical PSG, grade of OSA severity, and therapeutic level of Continuous Positive Airway Pressure (CPAP) and are reported in the text. This approach would allow qualitative phenotyping with widely accessible methodology in a routine clinical scenario and is of particular interest for the sleep specialist, surgical treatment decision-making, and customized OSA multimodality treatment.
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Affiliation(s)
- Marcello Bosi
- Pulmonary Operative Unit, Department of Thoracic Diseases, Morgagni-Pierantoni Hospital, Romagna Health Company, 47121 Forlì, Italy;
| | - Andrea De Vito
- Head & Neck Department, Ear Nose Throat (ENT) Unit, Santa Maria delle Croci Hospital, Romagna Health Company, 48121 Ravenna, Italy
- Correspondence:
| | - Danny Eckert
- Adelaide Institute for Sleep Health, A. Flinders University. Centre of Research Excellence, Adelaide 5049, Australia;
| | - Joerg Steier
- Lane Fox Unit/Sleep Disorders Centre, Guy’s & St Thomas’ National Health Service (NHS) Foundation Trust, London SE19RT, UK;
- Centre of Human & Aerospace Physiological Sciences, Faculty of Life Sciences and Medicine, King’s College, London WC2R 2LS, UK
| | - Bhik Kotecha
- Nuffield Health Brentwood, Shenfield Road, Brentwood, Essex CM15 8EH, UK;
| | - Claudio Vicini
- Head & Neck Department, ENT & Oral Surgery Unit, Morgagni-Pierantoni/Infermi Hospital, Romagna Health Company, 47121 Forlì, Italy;
- Ear Nose and Throat (ENT) Clinic, Special Surgery Department, Arcispedale S. Anna Hospital, Ferrara University, 44124 Ferrara, Italy
- Department of Otolaryngology Head and Neck surgery, S.Orsola-Malpighi University Hospital, 40138 Bologna, Italy
| | - Venerino Poletti
- Pulmonary Operative Unit, Department of Thoracic Diseases, Morgagni-Pierantoni Hospital, Romagna Health Company, 47121 Forlì, Italy;
- Department of Respiratory Diseases & Allergy, Aarhus University Hospital, 8200 Aarhus, Denmark
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13
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Martinot JB, Le-Dong NN, Cuthbert V, Denison S, Borel JC, Gozal D, Pépin JL. Respiratory Mandibular Movement Signals Reliably Identify Obstructive Hypopnea Events During Sleep. Front Neurol 2019; 10:828. [PMID: 31456731 PMCID: PMC6701450 DOI: 10.3389/fneur.2019.00828] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 07/18/2019] [Indexed: 12/04/2022] Open
Abstract
Context: Accurate discrimination between obstructive and central hypopneas requires quantitative assessments of respiratory effort by esophageal pressure (OeP) measurements, which preclude widespread implementation in sleep medicine practice. Mandibular Movement (MM) signals are closely associated with diaphragmatic effort during sleep. Objective: We aimed at reliably detecting obstructive off central hypopneas events using MM statistical characteristics. Methods: A bio-signal learning approach was implemented whereby raw MM fragments corresponding to normal breathing (NPB; n = 501), central (n = 263), and obstructive hypopneas (n = 1861) were collected from 28 consecutive patients (mean age = 54 years, mean AHI = 34.7 n/h) undergoing in-lab polysomnography (PSG) coupled with a MM magnetometer, and OeP recordings. Twenty three input features were extracted from raw data fragments to explore distinctive changes in MM signals. A Random Forest model was built upon those input features to classify the central and obstructive hypopnea events. External validation and interpretive analysis were performed to evaluate the model's performance and the contribution of each feature to the model's output. Results: Obstructive hypopneas were characterized by a longer duration (21.9 vs. 17.8 s, p < 10−6), more extreme low values (p < 10−6), a more negative trend reflecting mouth opening amplitude, wider variation, and the asymmetrical distribution of MM amplitude. External validation showed a reliable performance of the MM features-based classification rule (Kappa coefficient = 0.879 and a balanced accuracy of 0.872). The interpretive analysis revealed that event duration, lower percentiles, central tendency, and the trend of MM amplitude were the most important determinants of events. Conclusions: MM signals can be used as surrogate markers of OeP to differentiate obstructive from central hypopneas during sleep.
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Affiliation(s)
- Jean-Benoit Martinot
- Sleep Laboratory, CHU UCL Namur Site Sainte-Elisabeth, Namur, Belgium.,Institute of Experimental and Clinical Research, UCL Bruxelles Woluwe, Brussels, Belgium
| | | | | | | | - Jean C Borel
- HP2 INSERM U1042, Université Grenoble Alpes, Grenoble, France
| | - David Gozal
- Department of Child Health and Child Health Research Institute, University of Missouri, Columbia, MO, United States
| | - Jean L Pépin
- HP2 INSERM U1042, Université Grenoble Alpes, Grenoble, France
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14
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Sands SA, Terrill PI, Edwards BA, Taranto Montemurro L, Azarbarzin A, Marques M, de Melo CM, Loring SH, Butler JP, White DP, Wellman A. Quantifying the Arousal Threshold Using Polysomnography in Obstructive Sleep Apnea. Sleep 2019; 41:4608578. [PMID: 29228393 DOI: 10.1093/sleep/zsx183] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 11/07/2017] [Indexed: 11/14/2022] Open
Abstract
Study Objectives Precision medicine for obstructive sleep apnea (OSA) requires noninvasive estimates of each patient's pathophysiological "traits." Here, we provide the first automated technique to quantify the respiratory arousal threshold-defined as the level of ventilatory drive triggering arousal from sleep-using diagnostic polysomnographic signals in patients with OSA. Methods Ventilatory drive preceding clinically scored arousals was estimated from polysomnographic studies by fitting a respiratory control model (Terrill et al.) to the pattern of ventilation during spontaneous respiratory events. Conceptually, the magnitude of the airflow signal immediately after arousal onset reveals information on the underlying ventilatory drive that triggered the arousal. Polysomnographic arousal threshold measures were compared with gold standard values taken from esophageal pressure and intraoesophageal diaphragm electromyography recorded simultaneously (N = 29). Comparisons were also made to arousal threshold measures using continuous positive airway pressure (CPAP) dial-downs (N = 28). The validity of using (linearized) nasal pressure rather than pneumotachograph ventilation was also assessed (N = 11). Results Polysomnographic arousal threshold values were correlated with those measured using esophageal pressure and diaphragm EMG (R = 0.79, p < .0001; R = 0.73, p = .0001), as well as CPAP manipulation (R = 0.73, p < .0001). Arousal threshold estimates were similar using nasal pressure and pneumotachograph ventilation (R = 0.96, p < .0001). Conclusions The arousal threshold in patients with OSA can be estimated using polysomnographic signals and may enable more personalized therapeutic interventions for patients with a low arousal threshold.
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Affiliation(s)
- Scott A Sands
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.,Department of Allergy, Immunology and Respiratory Medicine and Central Clinical School, The Alfred and Monash University, Melbourne, Victoria, Australia
| | - Philip I Terrill
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Queensland, Australia
| | - Bradley A Edwards
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.,Department of Physiology, Sleep and Circadian Medicine Laboratory, Monash University, Melbourne, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Luigi Taranto Montemurro
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Ali Azarbarzin
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Melania Marques
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.,Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas, University of São Paulo School of Medicine, São Paulo, Brazil
| | - Camila M de Melo
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Stephen H Loring
- Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - James P Butler
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - David P White
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
| | - Andrew Wellman
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, MA
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15
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Mann DL, Terrill PI, Azarbarzin A, Mariani S, Franciosini A, Camassa A, Georgeson T, Marques M, Taranto-Montemurro L, Messineo L, Redline S, Wellman A, Sands SA. Quantifying the magnitude of pharyngeal obstruction during sleep using airflow shape. Eur Respir J 2019; 54:13993003.02262-2018. [DOI: 10.1183/13993003.02262-2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 04/03/2019] [Indexed: 11/05/2022]
Abstract
Rationale and objectivesNon-invasive quantification of the severity of pharyngeal airflow obstruction would enable recognition of obstructiveversuscentral manifestation of sleep apnoea, and identification of symptomatic individuals with severe airflow obstruction despite a low apnoea–hypopnoea index (AHI). Here we provide a novel method that uses simple airflow-versus-time (“shape”) features from individual breaths on an overnight sleep study to automatically and non-invasively quantify the severity of airflow obstruction without oesophageal catheterisation.Methods41 individuals with suspected/diagnosed obstructive sleep apnoea (AHI range 0–91 events·h−1) underwent overnight polysomnography with gold-standard measures of airflow (oronasal pneumotach: “flow”) and ventilatory drive (calibrated intraoesophageal diaphragm electromyogram: “drive”). Obstruction severity was defined as a continuous variable (flow:drive ratio). Multivariable regression used airflow shape features (inspiratory/expiratory timing, flatness, scooping, fluttering) to estimate flow:drive ratio in 136 264 breaths (performance based on leave-one-patient-out cross-validation). Analysis was repeated using simultaneous nasal pressure recordings in a subset (n=17).ResultsGold-standard obstruction severity (flow:drive ratio) varied widely across individuals independently of AHI. A multivariable model (25 features) estimated obstruction severity breath-by-breath (R2=0.58versusgold-standard, p<0.00001; mean absolute error 22%) and the median obstruction severity across individual patients (R2=0.69, p<0.00001; error 10%). Similar performance was achieved using nasal pressure.ConclusionsThe severity of pharyngeal obstruction can be quantified non-invasively using readily available airflow shape information. Our work overcomes a major hurdle necessary for the recognition and phenotyping of patients with obstructive sleep disordered breathing.
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16
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Chuang SY, Teng A, Butler J, Gandevia S, Narang I, Briggs N, Selvadurai H, Jaffe A. Quantitative assessment of nocturnal neural respiratory drive in children with and without obstructive sleep apnoea using surface EMG. Exp Physiol 2019; 104:755-764. [PMID: 30821402 DOI: 10.1113/ep087441] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/27/2019] [Indexed: 01/10/2023]
Abstract
NEW FINDINGS What is the central question of this study? Recent studies have suggested potential utility of non-normalized respiratory muscle EMG as an index of neural respiratory drive (NRD). Whether NRD measured using non-normalized surface EMG of the lateral chest wall overlying the diaphragm (sEMGcw) recorded during nocturnal clinical polysomnography can differentiate children with and without obstructive sleep apnoea (OSA) is not known. What is the main finding and its importance? Non-normalized sEMGcw was increased in children with OSA and an additional group of snoring children without OSA but subjectively increased respiratory effort compared with primary snorers. The sEMGcw has potential clinical utility in evaluation of children with sleep-disordered breathing as an objective, non-invasive, non-volitional marker of NRD. ABSTRACT Our aim was to investigate whether neural respiratory drive measured by non-normalized surface EMG recorded from the chest wall overlying the diaphragm (sEMGcw) differentiates children with and without obstructive sleep apnoea (OSA). Polysomnography data of children aged 0-18 years were divided into the following three groups: (i) primary snorers (PS); (ii) snoring children without OSA but with increased work of breathing (incWOB; subjective physician report of increased respiratory effort during sleep); and (iii) children with OSA [obstructive apnoea-hypopnoea index (OAHI) >1 h-1 ]. Excerpts of sEMGcw obtained during tidal unobstructed breathing from light, deep and rapid eye movement sleep were exported for quantitative analysis. Overnight polysomnography data from 45 PS [median age 4.4 years (interquartile range 3.0-7.7 years), OAHI 0 h-1 (0.0-0.2 h-1 )], 19 children with incWOB [age 2.8 years (2.4-5.7 years), OAHI 0.1 h-1 (0.0-0.4 h-1 )] and 27 children with OSA [age 3.6 years (2.6-6.2 years), OAHI 3.7 h-1 (2.3-6.9 h-1 )] were analysed. The sEMGcw was higher in those with OSA [8.47 μV (5.98-13.07 μV); P < 0.0001] and incWOB [8.97 μV (5.94-13.43 μV); P < 0.001] compared with PS [4.633 μV (2.98-6.76 μV)]. There was no significant difference in the sEMGcw between children with incWOB and OSA (P = 0.78). Log sEMGcw remained greater in children with OSA and incWOB compared with PS after age, body mass index centiles, sleep stages and sleep positions were included in the mixed linear models (P < 0.0001). The correlation between sEMGcw and OAHI in children without OSA was small (rs = 0.254, P = 0.04). The sEMGcw is increased in children with OSA and incWOB compared with PS.
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Affiliation(s)
- Sandra Y Chuang
- Respiratory Department, Sydney Children's Hospital, Randwick, NSW, Australia.,School of Women's and Children's Health, University of New South Wales, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Arthur Teng
- School of Women's and Children's Health, University of New South Wales, Sydney Children's Hospital, Randwick, NSW, Australia.,Sleep Medicine Department, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Jane Butler
- Neuroscience Research Australia, Randwick, NSW, Australia.,School of Medical Sciences, Wallace Wurth Building, University of New South Wales, Kensington, NSW, Australia
| | - Simon Gandevia
- Neuroscience Research Australia, Randwick, NSW, Australia.,School of Medical Sciences, Wallace Wurth Building, University of New South Wales, Kensington, NSW, Australia
| | - Indra Narang
- Department of Paediatrics, Hospital for Sick Children, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada
| | - Nancy Briggs
- School of Women's and Children's Health, University of New South Wales, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Hiran Selvadurai
- Respiratory Department, Children's Hospital Westmead, Westmead, NSW, Australia
| | - Adam Jaffe
- Respiratory Department, Sydney Children's Hospital, Randwick, NSW, Australia.,School of Women's and Children's Health, University of New South Wales, Sydney Children's Hospital, Randwick, NSW, Australia
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17
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Luo G, Yang Z. The application of ECG cancellation in diaphragmatic electromyographic by using stationary wavelet transform. Biomed Eng Lett 2019; 8:259-266. [PMID: 30603209 DOI: 10.1007/s13534-018-0064-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 02/19/2018] [Accepted: 03/22/2018] [Indexed: 11/25/2022] Open
Abstract
In this paper, we present and investigate a special kind of stationary wavelet algorithm using "inverse" hard threshold to eliminate the electrocardiogram (ECG) interference included in diaphragmatic electromyographic (EMGdi). Differing from traditional wavelet hard threshold, "inverse" hard threshold is used to shrink strong coefficients of ECG interference and reserve weak coefficients of EMGdi signal. Meanwhile, a novel QRS location algorithm is proposed for the position detection of R wave by using low frequency coefficients in this paper. With the proposed method, raw EMGdi is decomposed by wavelet at fifth scale. Then, each ECG interference threshold is calculated by mean square, which is estimated by wavelet coefficients in the ECG cycle at each level. Finally, ECG interference wavelet coefficients are removed by "inverse" hard threshold, and then the de-noised signal is reconstructed by wavelet coefficients. The simulation and clinical EMGdi de-noising results show that the "inverse" hard threshold investigated in this paper removes the ECG interference in EMGdi availably and reserves its signal characteristics effectively, as compared to wavelet threshold.
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Affiliation(s)
- Guo Luo
- Nanfang College of Sun Yat-sen University, Guangzhou, China
| | - Zhi Yang
- Nanfang College of Sun Yat-sen University, Guangzhou, China
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19
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Phenotyping the pathophysiology of obstructive sleep apnea using polygraphy/polysomnography: a review of the literature. Sleep Breath 2018; 22:579-592. [PMID: 29318567 DOI: 10.1007/s11325-017-1613-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/03/2017] [Accepted: 12/19/2017] [Indexed: 12/19/2022]
Abstract
Continuous positive airway pressure (CPAP) is the first-line treatment for the majority of patients affected by obstructive sleep apnea syndrome (OSA). However, long-term compliance with CPAP therapy may result limited and alternatives to CPAP therapy are required to address the increasing need to provide tailored therapeutic options. Understanding the pathophysiological traits (PTs) of OSA patients [upper airway (UA) anatomical collapsibility, loop gain (LG), arousal threshold (AT), and UA gain (UAG)] lies at the heart of the customized OSA treatment. However, sleep research laboratories capable to phenotype OSA patients are sparse and the diagnostic procedures time-consuming, costly, and requiring significant expertise. The question arises whether the use of routine clinical polysomnography or nocturnal portable multi-channel monitoring (PSG/PM) can provide sufficient information to characterize the above traits. The aim of the present review is to deduce if the information obtainable from the clinical PSG/PM analysis, independently of the scope and context of the original studies, is clinically useful to define qualitatively the PTs of individual OSA patients. In summary, it is possible to identify four patterns using PSG/PM that are consistent with an altered UA collapsibility, three that are consistent with altered LG, two with altered AT, and three consistent with flow limitation/UA muscle response. Furthermore, some PSG/PM indexes and patterns, useful for the suitable management of OSA patient, have been discussed. The delivery of this clinical approach to phenotype pathophysiological traits will allow patients to benefit in a wider range of sleep services by facilitating tailored therapeutic options.
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20
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Influence of Parameter Selection in Fixed Sample Entropy of Surface Diaphragm Electromyography for Estimating Respiratory Activity. ENTROPY 2017. [DOI: 10.3390/e19090460] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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21
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Martinot JB, Le-Dong NN, Cuthbert V, Denison S, Silkoff PE, Guénard H, Gozal D, Pepin JL, Borel JC. Mandibular Movements As Accurate Reporters of Respiratory Effort during Sleep: Validation against Diaphragmatic Electromyography. Front Neurol 2017; 8:353. [PMID: 28785240 PMCID: PMC5519525 DOI: 10.3389/fneur.2017.00353] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/05/2017] [Indexed: 11/29/2022] Open
Abstract
Context Mandibular movements (MM) are considered as reliable reporters of respiratory effort (RE) during sleep and sleep disordered breathing (SDB), but MM accuracy has never been validated against the gold standard diaphragmatic electromyography (EMG-d). Objectives To assess the degree of agreement between MM and EMG-d signals during different sleep stages and abnormal respiratory events. Methods Twenty-five consecutive adult patients with SDB were studied by polysomnography (PSG) that also included multipair esophageal diaphragm electromyography and a magnetometer to record MM. EMG-d activity (microvolt) and MM (millimeter) amplitudes were extracted by envelope processing. Agreement between signals amplitudes was evaluated by mixed linear regression and cross-correlation function and in segments of PSG including event-free and SDB periods. Results The average total sleep time was 370 ± 18 min and the apnea hypopnea index was 24.8 ± 5.2 events/h. MM and EMG-d amplitudes were significantly cross-correlated: median r (95% CI): 0.67 (0.23–0.96). A mixed linear model showed that for each 10 µV of increase in EMG-d activity, MM amplitude increased by 0.28 mm. The variations in MM amplitudes (median range: 0.11–0.84 mm) between normal breathing, respiratory effort-related arousal, obstructive, mixed, and central apnea periods closely corresponded to those observed with EMG-d activity (median range: 2.11–8.23 µV). Conclusion MM amplitudes change proportionally to diaphragmatic EMG activity and accurately identify variations of RE during normal sleep and SDB.
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Affiliation(s)
| | | | | | | | | | | | - David Gozal
- University of Chicago, Chicago, IL, United States
| | - Jean-Louis Pepin
- CHU de Grenoble, Laboratoire EFCR, Pôle Thorax et Vaisseaux, Grenoble, France.,University Grenoble Alps, HP2 INSERM U1042, Grenoble, France
| | - Jean-Christian Borel
- University Grenoble Alps, HP2 INSERM U1042, Grenoble, France.,AGIR à dom. Association, Meylan, France
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Steier J, Cade N, Walker B, Moxham J, Jolley C. Observational Study of Neural Respiratory Drive During Sleep at High Altitude. High Alt Med Biol 2017. [PMID: 28628341 DOI: 10.1089/ham.2016.0097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Steier, Joerg, Nic Cade, Ben Walker, John Moxham, and Caroline Jolley. Observational study of neural respiratory drive during sleep at high altitude. High Alt Med Biol. 18:242-248, 2017. AIMS Ventilation at altitude changes due to altered levels of pO2, pCO2 and the effect on blood pH. Nocturnal ventilation is particularly exposed to these changes. We hypothesized that an increasing neural respiratory drive (NRD) is associated with the severity of sleep-disordered breathing at altitude. METHODS Mountaineers were studied at sea level (London, United Kingdom), and at altitude at the Aconcagua (Andes, Argentina). NRD was measured as electromyogram of the diaphragm (EMGdi) overnight by a transesophageal multi-electrode catheter; results were reported for sea level, 3,380 m, 4,370 m, and 5,570 m. RESULTS Four healthy subjects (3 men, age 31(3)years, body mass index 23.6(0.9)kg/m2, neck circumference 37.0(2.7)cm, forced expiratory volume in 1 second 111.8(5.1)%predicted, and forced vital capacity 115.5(6.3)%predicted) were studied. No subject had significant sleep abnormalities at sea level. Time to ascent to 3,380 m was 1 day, to 4,370 m was 5 days, and the total nights at altitude were 21 days. The oxygen desaturation index (4% oxygen desaturation index [ODI] 0.8(0.4), 22.0 (7.2), 61.4 (26.9), 144.9/hour, respectively) and the EMGdi (5.2 (1.9), 12.8 (5.1), 14.1 (3.4), 18.5%, respectively) increased with the development of periodic breathing at altitude, whereas the average SpO2 declined (97.5 (1.3), 84.8 (0.5), 81.0 (4.1), 68.5%, respectively). The average EMGdi correlated well with the 4%ODI (r = 0.968, p = 0.032). CONCLUSION NRD sleep increases at altitude in relation to the severity of periodic breathing.
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Affiliation(s)
- Joerg Steier
- 1 Faculty of Life Sciences and Medicine, King's College London , London, United Kingdom .,2 Lane Fox Respiratory Unit and Sleep Disorders Centre, Guy's and St. Thomas' NHS Foundation , London, United Kingdom
| | - Nic Cade
- 3 Synthetic and Systems Biochemistry of the Microtubule Cytoskeleton Laboratory, Francis Crick Institute , London, United Kingdom
| | - Ben Walker
- 1 Faculty of Life Sciences and Medicine, King's College London , London, United Kingdom
| | - John Moxham
- 1 Faculty of Life Sciences and Medicine, King's College London , London, United Kingdom
| | - Caroline Jolley
- 1 Faculty of Life Sciences and Medicine, King's College London , London, United Kingdom
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Laghi F, Owens RL. COPD+OSA: can two bad things be good for you? Thorax 2016; 72:204-205. [PMID: 28011858 DOI: 10.1136/thoraxjnl-2016-209569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Franco Laghi
- Loyola University of Chicago Stritch School of Medicine, Maywood, Illinois, USA.,Edward Hines, Jr. Veterans Affairs Hospital, Hines, Illinois, USA
| | - Robert L Owens
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California San Diego, La Jolla, California, USA
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24
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He BT, Lu G, Xiao SC, Chen R, Steier J, Moxham J, Polkey MI, Luo YM. Coexistence of OSA may compensate for sleep related reduction in neural respiratory drive in patients with COPD. Thorax 2016; 72:256-262. [PMID: 27807016 PMCID: PMC5339571 DOI: 10.1136/thoraxjnl-2016-208467] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 09/09/2016] [Accepted: 10/05/2016] [Indexed: 11/10/2022]
Abstract
Background The mechanisms underlying sleep-related hypoventilation in patients with coexisting COPD and obstructive sleep apnoea (OSA), an overlap syndrome, are incompletely understood. We compared neural respiratory drive expressed as diaphragm electromyogram (EMGdi) and ventilation during stage 2 sleep in patients with COPD alone and patients with overlap syndrome. Methods EMGdi and airflow were recorded during full polysomnography in 14 healthy subjects, 14 patients with OSA and 39 consecutive patients with COPD. The ratio of tidal volume to EMGdi was measured to indirectly assess upper airway resistance. Results Thirty-five patients with COPD, 12 healthy subjects and 14 patients with OSA completed the study. Of 35 patients with COPD, 19 had COPD alone (FEV1 38.5%±16.3%) whereas 16 had an overlap syndrome (FEV1 47.5±16.2%, AHI 20.5±14.1 events/hour). Ventilation (VE) was lower during stage 2 sleep than wakefulness in both patients with COPD alone (8.6±2.0 to 6.5±1.5 L/min, p<0.001) and those with overlap syndrome (8.3±2.0 to 6.1±1.8 L/min). Neural respiratory drive from wakefulness to sleep decreased significantly for patients with COPD alone (29.5±13.3% to 23.0±8.9% of maximal, p<0.01) but it changed little in those with overlap syndrome. The ratio of tidal volume to EMGdi was unchanged from wakefulness to sleep in patients with COPD alone and healthy subjects but was significantly reduced in patients with OSA or overlap syndrome (p<0.05). Conclusions Stage 2 sleep-related hypoventilation in COPD alone is due to reduction of neural respiratory drive, but in overlap syndrome it is due to increased upper airway resistance.
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Affiliation(s)
- Bai-Ting He
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China
| | - Gan Lu
- Jiangsu Provincial Official Hospital, Nanjing, China
| | - Si-Chang Xiao
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China
| | - Rui Chen
- Department of Respiratory Medicine, Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Joerg Steier
- Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - John Moxham
- Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Michael I Polkey
- NIHR Respiratory Biomedical Research Unit, The Royal Brompton and Harefield NHS Foundation Trust and Imperial College, Royal Brompton Hospital, London, UK
| | - Yuan-Ming Luo
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China
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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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Xiao SC, He BT, Steier J, Moxham J, Polkey MI, Luo YM. Neural Respiratory Drive and Arousal in Patients with Obstructive Sleep Apnea Hypopnea. Sleep 2015; 38:941-9. [PMID: 25669181 DOI: 10.5665/sleep.4746] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 11/15/2014] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES It has been hypothesized that arousals after apnea and hypopnea events in patients with obstructive sleep apnea are triggered when neural respiratory drive exceeds a certain level, but this hypothesis is based on esophageal pressure data, which are dependent on flow and lung volume. We aimed to determine whether a fixed threshold of respiratory drive is responsible for arousal at the termination of apnea and hypopnea using a flow independent technique (esophageal diaphragm electromyography, EMGdi) in patients with obstructive sleep apnea. SETTING Sleep center of state Key Laboratory of Respiratory Disease. PATIENTS Seventeen subjects (two women, mean age 53 ± 11 years) with obstructive sleep apnea/hypopnea syndrome were studied. METHODS We recorded esophageal pressure and EMGdi simultaneously during overnight full polysomnography in all the subjects. MEASUREMENTS AND RESULTS A total of 709 hypopnea events and 986 apnea events were analyzed. There was wide variation in both esophageal pressure and EMGdi at the end of both apnea and hypopnea events within a subject and stage 2 sleep. The EMGdi at the end of events that terminated with arousal was similar to those which terminated without arousal for both hypopnea events (27.6% ± 13.9%max vs 29.9% ± 15.9%max, P = ns) and apnea events (22.9% ± 11.5%max vs 22.1% ± 12.6%max, P = ns). The Pes at the end of respiratory events terminated with arousal was also similar to those terminated without arousal. There was a small but significant difference in EMGdi at the end of respiratory events between hypopnea and apnea (25.3% ± 14.2%max vs 21.7% ± 13.2%max, P < 0.05]. CONCLUSIONS Our data do not support the concept that there is threshold of neural respiratory drive that is responsible for arousal in patients with obstructive sleep apnea.
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Affiliation(s)
- Si-Chang Xiao
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China
| | - Bai-Ting He
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China
| | - Joerg Steier
- Lane Fox Respiratory Unit, Sleep Disorders Centre, Guy's & St Thomas' NHS Foundation Trust, London, UK.,Department of Respiratory Medicine, King's College London School of Medicine, London, UK
| | - John Moxham
- Department of Respiratory Medicine, King's College London School of Medicine, London, UK
| | - Michael I Polkey
- NIHR Respiratory Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, UK
| | - Yuan-Ming Luo
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, China
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Estrada L, Torres A, Sarlabous L, Jané R. Improvement in Neural Respiratory Drive Estimation From Diaphragm Electromyographic Signals Using Fixed Sample Entropy. IEEE J Biomed Health Inform 2015; 20:476-85. [PMID: 25667362 DOI: 10.1109/jbhi.2015.2398934] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Diaphragm electromyography is a valuable technique for the recording of electrical activity of the diaphragm. The analysis of diaphragm electromyographic (EMGdi) signal amplitude is an alternative approach for the quantification of the neural respiratory drive (NRD). The EMGdi signal is, however, corrupted by electrocardiographic (ECG) activity, and this presence of cardiac activity can make the EMGdi interpretation more difficult. Traditionally, the EMGdi amplitude has been estimated using the average rectified value (ARV) and the root mean square (RMS). In this study, surface EMGdi signals were analyzed using the fixed sample entropy (fSampEn) algorithm, and compared to the traditional ARV and RMS methods. The fSampEn is calculated using a tolerance value fixed and independent of the standard deviation of the analysis window. Thus, this method quantifies the amplitude of the complex components of stochastic signals (such as EMGdi), and being less affected by changes in amplitude due to less complex components (such as ECG). The proposed method was tested in synthetic and recorded EMGdi signals. fSampEn was less sensitive to the effect of cardiac activity on EMGdi signals with different levels of NRD than ARV and RMS amplitude parameters. The mean and standard deviation of the Pearson's correlation values between inspiratory mouth pressure (an indirect measure of the respiratory muscle activity) and fSampEn, ARV, and RMS parameters, estimated in the recorded EMGdi signal at tidal volume (without inspiratory load), were 0.38±0.12, 0.27±0.11 , and 0.11±0.13, respectively. Whereas at 33 cmH2O (maximum inspiratory load) were 0.83±0.02, 0.76±0.07, and 0.61±0.19 , respectively. Our findings suggest that the proposed method may improve the evaluation of NRD.
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Luo YM, He BT, Wu YX, Yuan H, Xu J, Moxham J, Polkey M. Neural respiratory drive and ventilation in patients with chronic obstructive pulmonary disease during sleep. Am J Respir Crit Care Med 2014; 190:227-9. [PMID: 25025355 DOI: 10.1164/rccm.201402-0302le] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Yuan-Ming Luo
- 1 State Key Laboratory of Respiratory Disease Guangzhou Medical University Guangzhou, China
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Reilly CC, Jolley CJ, Ward K, MacBean V, Moxham J, Rafferty GF. Neural respiratory drive measured during inspiratory threshold loading and acute hypercapnia in healthy individuals. Exp Physiol 2013; 98:1190-8. [PMID: 23504646 DOI: 10.1113/expphysiol.2012.071415] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Understanding the effects of respiratory load on neural respiratory drive and respiratory pattern are key to understanding the regulation of load compensation in respiratory disease. The aim of the study was to examine and compare the recruitment pattern of the diaphragm and parasternal intercostal muscles when the respiratory system was loaded using two methods. Twelve subjects performed incremental inspiratory threshold loading up to 50% of their maximal inspiratory pressure, and 10 subjects underwent incremental, steady-state hypercapnia to a maximal inspired CO2 of 5%. The diaphragmatic electromyogram (EMGdi) was measured using a multipair oesophageal catheter, and the parasternal intercostal muscle EMG (sEMGpara) was recorded from bipolar surface electrodes positioned in the second intercostal space. The EMGdi and sEMGpara were analysed over the last minute of each increment of both protocols, normalized using the peak EMG recorded during maximal respiratory manoeuvres and expressed as EMG%max. The EMGdi%max and sEMGpara%max increased in parallel during the two loading methods, although EMGdi%max was consistently greater than sEMGpara%max in both conditions, inspiratory threshold loading [bias (SD) 9 (3)%, 95% limits of agreement 4-15%] and hypercapnia [bias (SD) 6 (3)%, 95% limits of agreement -0.05 to 12%]. Inspiratory threshold loading resulted in more pronounced increases in mean (SD) EMGdi%max [10 (7)-45 (28)%] and sEMGpara%max [5.3 (3.1)-40 (28)%] from baseline compared with EMGdi%max [7 (4)-21 (8)%] and sEMGpara%max [4.7 (2.3)-10 (4)%] during hypercapnia, despite comparable levels of ventilation. These data support the use of sEMGpara%max, as a non-invasive alternative to EMGdi%max recorded with an invasive oesophageal electrode catheter, for the quantification of neural respiratory drive. This technique should make evaluation of respiratory muscle function easier to undertake and therefore more readily acceptable in patients with respiratory disease, in whom transduction of neural respiratory drive to pressure generation can be compromised.
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Affiliation(s)
- Charles C Reilly
- Department of Asthma, Allergy and Respiratory Science, King's College London School of Medicine, London, UK.
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30
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Steier J, Seymour J, Rafferty GF, Jolley CJ, Solomon E, Luo Y, Man WDC, Polkey MI, Moxham J. Continuous Transcutaneous Submental Electrical Stimulation in Obstructive Sleep Apnea. Chest 2011; 140:998-1007. [DOI: 10.1378/chest.10-2614] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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31
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Cui L, Wang JH, Wang M, Huang M, Wang CY, Xia H, Xu JG, Li MX, Wang S. Injection of l-glutamate into the insular cortex produces sleep apnea and serotonin reduction in rats. Sleep Breath 2011; 16:845-53. [DOI: 10.1007/s11325-011-0586-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 08/16/2011] [Accepted: 08/26/2011] [Indexed: 10/17/2022]
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Luo Y, Li R, Jolley C, Wu H, Steier J, Moxham J, Zhong N. Neural Respiratory Drive in Patients with COPD during Exercise Tests. Respiration 2011; 81:294-301. [DOI: 10.1159/000317136] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 04/05/2010] [Indexed: 11/19/2022] Open
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33
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Qin YY, Steier J, Jolley C, Moxham J, Zhong NS, Luo YM. Efficiency of Neural Drive During Exercise in Patients With COPD and Healthy Subjects. Chest 2010; 138:1309-15. [DOI: 10.1378/chest.09-2824] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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34
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Steier J, Jolley CJ, Seymour J, Ward K, Luo YM, Polkey MI, Moxham J. Increased load on the respiratory muscles in obstructive sleep apnea. Respir Physiol Neurobiol 2010; 171:54-60. [PMID: 20117253 DOI: 10.1016/j.resp.2010.01.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 01/21/2010] [Accepted: 01/22/2010] [Indexed: 11/19/2022]
Abstract
We wished to quantify, in patients with obstructive sleep apnoea (OSA), the activity of the respiratory muscles in relation to upper airway occlusion and patency in sleep. We hypothesized that particular levels of neuromuscular activation are directly associated with upper airway patency. 21 patients with previously diagnosed OSA and 21 healthy control subjects underwent respiratory muscle testing and polysomnography. Neural respiratory drive, as measured by the electromyogram of the diaphragm (EMG(di)) was elevated in the obese OSA patients, awake and supine (13.1(5.6)%max), compared to normal subjects (mean (SD) 8.1(2.3)%max, p<0.01). During unobstructed breathing in sleep (stage N2) normal subjects had an EMG(di) of 7.7(3.9) compared to 22.8(19.2)%max in the OSA group (p<0.001). Prior to airway occlusion, EMG(submandibular) and EMG(di) dropped markedly, and then, following occlusion, increased progressively to their highest levels at airflow onset. Patients with OSA require specific and increased levels of neural respiratory drive to sustain ventilation in sleep.
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Affiliation(s)
- Joerg Steier
- King's College London School of Medicine, London, UK.
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Luo Y, Qiu Z, Wu H, Steier J, Jolley C, Zhong N, Moxham J, Polkey M. Neural drive during continuous positive airway pressure (CPAP) and pressure relief CPAP. Sleep Med 2009; 10:731-8. [DOI: 10.1016/j.sleep.2008.06.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 06/07/2008] [Accepted: 06/09/2008] [Indexed: 10/21/2022]
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36
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Luo YM, Tang J, Jolley C, Steier J, Zhong NS, Moxham J, Polkey MI. Distinguishing obstructive from central sleep apnea events: diaphragm electromyogram and esophageal pressure compared. Chest 2009; 135:1133-1141. [PMID: 19118271 DOI: 10.1378/chest.08-1695] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Distinguishing central sleep apnea (CSA) from obstructive sleep apnea (OSA) can be clinically important because different types of apnea may require different treatment approaches. Academically, this distinction is important for investigating the pathological mechanism of different types of sleep apnea. Conventional polysomnography (PSG) with recording of chest and abdominal movement may overestimate the frequency of CSA, leading to inappropriate treatment of sleep-disordered breathing. We hypothesized that diaphragm electromyogram (EMGdi) could be a useful technique to assess neural respiratory drive and respiratory effort and, therefore, to distinguish accurately CSA from OSA. METHODS A multipair esophageal electrode catheter mounted with a balloon was used to record the EMGdi and esophageal pressure (Pes) during overnight PSG. Nineteen patients were included in the study, 12 of whom had previously been identified as having central apnea-hypopnea on a diagnostic PSG undertaken for symptoms that suggest OSA and 7 of whom were known to have heart failure. RESULTS A good relationship was found between the swing of Pes and the root mean (+/- SD) square of the EMGdi during OSA events (0.89 +/- 0.10). About one third of CSA events diagnosed by uncalibrated respiratory inductance plethysmography could not be confirmed by Pes or EMGdi. No difference was found in the number of CSAs diagnosed by Pes (1,319) vs EMGdi (1,293; p > 0.01). CONCLUSIONS We conclude that both Pes and EMGdi measurements are useful in accurately differentiating central from obstructive respiratory events. Conventional PSG with recording of chest and abdominal movement overestimates the frequency of CSA events.
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Affiliation(s)
- Yuan-Ming Luo
- Guangzhou Medical College, State Key Laboratory of Respiratory Disease, Guangzhou, People's Republic of China.
| | - Jing Tang
- Guangzhou Medical College, State Key Laboratory of Respiratory Disease, Guangzhou, People's Republic of China
| | | | | | - Nan-Shan Zhong
- Guangzhou Medical College, State Key Laboratory of Respiratory Disease, Guangzhou, People's Republic of China
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Abstract
The usefulness of diaphragm electromyography recorded from an oesophageal electrode depends on a reliable signal which is free of artefact. The diaphragm EMG (electromyogram) recorded from chest wall surface electrodes may be unreliable because of signal contamination from muscle activity other than the diaphragm. Initially, the oesophageal electrode catheter for human studies had only one electrode pair, which could be difficult to position accurately and was influenced by a change in lung volume. Recently, a multipair oesophageal electrode has been developed which allows a high-quality EMG to be recorded. In the present review, the progress of oesophageal electrode design is outlined. The effects of signal contamination, electrode movement and particularly the effect of change in lung volume on the diaphragm EMG are discussed. The diaphragm EMG, recorded from a multipair oesophageal electrode, is useful to assess neural respiratory drive and diaphragm function in different groups of patients with respiratory disease, including patients with neuromuscular disease and sleep-disordered breathing, and those in the intensive care unit. When combined with cervical and cranial magnetic stimulation, an oesophageal electrode can be used to partition the central respiratory response time and phrenic nerve conduction time.
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