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Antonaglia C, Citton GM, Soave S, Salton F, Ruaro B, Confalonieri P, Confalonieri M. Deciphering Loop Gain complexity: a primer for understanding a pathophysiological trait of Obstructive Sleep Apnea patients. Respir Med 2024; 234:107820. [PMID: 39332779 DOI: 10.1016/j.rmed.2024.107820] [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: 04/21/2024] [Revised: 09/23/2024] [Accepted: 09/24/2024] [Indexed: 09/29/2024]
Abstract
Loop Gain (LG), a concept borrowed from engineering used to describe the stability of electrical circuits under negative feedback, has emerged as a crucial pathophysiological trait in sleep respiratory disorders. In simple terms, LG measures how the respiratory control system reacts to changes in breathing. A high LG suggests that minor disturbances in breathing prompt exaggerated responses, potentially leading to instability and oscillations in respiratory patterns. Conversely, a low LG implies that the system responds more gently to disturbances, resulting in stable and well-regulated breathing. However, understanding the concept of loop gain presents challenges due to its dynamic nature across various sleep respiratory disorders, sleep stages, positions, and interactions with other pathophysiological traits. Recent efforts have aimed to identify a non-invasive method for assessing LG, with some evidence suggesting that information regarding pathophysiological traits can be extracted from polysomnography. There exists a clinical imperative for physician to unravel the intricacies of LG when managing Obstructive Sleep Apnea (OSA) patients, because LG abnormalities delineate a distinct pathophysiological phenotype of OSA. Specifically, certain patients exhibit a high LG as the primary factor driving sleep apnea, influencing treatment outcomes. For instance, individuals with high LG may respond differently to therapies such as continuous positive airway pressure (CPAP) or oral appliances compared to those with normal LG, or they can be treated with specific drugs or combination therapies. Thus, understanding LG becomes paramount for precise assessment of OSA patients and is fundamental for optimizing a personalized and effective treatment approach.
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Affiliation(s)
- Caterina Antonaglia
- Pulmonology Unit, Department of Medical Surgical and Health Sciences, Hospital of Cattinara, University of Trieste, 34149 Trieste, Italy.
| | - Gloria Maria Citton
- Pulmonology Unit, Department of Medical Surgical and Health Sciences, Hospital of Cattinara, University of Trieste, 34149 Trieste, Italy
| | - Sara Soave
- Pulmonology Unit, Department of Medical Surgical and Health Sciences, Hospital of Cattinara, University of Trieste, 34149 Trieste, Italy
| | - Francesco Salton
- Pulmonology Unit, Department of Medical Surgical and Health Sciences, Hospital of Cattinara, University of Trieste, 34149 Trieste, Italy
| | - Barbara Ruaro
- Pulmonology Unit, Department of Medical Surgical and Health Sciences, Hospital of Cattinara, University of Trieste, 34149 Trieste, Italy
| | - Paola Confalonieri
- Pulmonology Unit, Department of Medical Surgical and Health Sciences, Hospital of Cattinara, University of Trieste, 34149 Trieste, Italy
| | - Marco Confalonieri
- Pulmonology Unit, Department of Medical Surgical and Health Sciences, Hospital of Cattinara, University of Trieste, 34149 Trieste, Italy
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Wang X, Zhou T, Huang W, Zhang J, Zou J, Guan J, Yi H, Yin S. Differences in Physiologic Endotypes Between Nonpositional and Positional OSA: Results From the Shanghai Sleep Health Study Cohort. Chest 2024; 166:212-225. [PMID: 38218217 DOI: 10.1016/j.chest.2024.01.021] [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: 03/23/2023] [Revised: 12/04/2023] [Accepted: 01/07/2024] [Indexed: 01/15/2024] Open
Abstract
BACKGROUND Positional OSA (POSA) is a recognized subtype of OSA that exhibits distinct endotypic characteristics when compared with nonpositional OSA (NPOSA). The basis for the disparity in endotypes between these subtypes remains poorly understood. RESEARCH QUESTION (1) Do individuals with NPOSA and POSA have different underlying OSA endotypes? (2) Which endotypic characteristics are critical in determining NPOSA and POSA severity? STUDY DESIGN AND METHODS Within the Shanghai Sleep Health Study cohort, individuals with OSA were recruited and classified as having POSA or NPOSA. Endotypes were calculated using polysomnography. RESULTS Endotype analysis was conducted in 1,036 individuals with OSA. Compared with individuals with NPOSA, those with POSA had lower loop gain calculated during all sleep stages and all sleep positions (0.55; interquartile range [IQR], 0.46-0.66 vs 0.68, IQR, 0.52-0.90; P < .001), lower arousal threshold calculated during all sleep stages and all sleep positions (ArTHAll) (138.67; IQR, 118.94-180.87 percentage of the eupneic ventilation [%Veupnea] vs 189.00; IQR, 129.71-257.76 %Veupnea; P < .001), lower pharyngeal collapsibility calculated during all sleep stages and all sleep positions (VpassiveAll) (91.85; IQR, 83.13-95.15 %Veupnea vs 76.38; IQR, 23.77-92.08 %Veupnea; P < .001), and higher muscle compensation calculated during all sleep stages and all sleep positions (6.50; IQR, -6.77 to 16.39 %Veupnea vs 3.65; IQR, -10.47 to 12.14 %Veupnea; P = .003). Logistic regression analyses indicated that higher VpassiveAll was associated with increased odds of POSA vs NPOSA. In NPOSA, fully adjusted linear regression analyses indicated that VpassiveAll (β = -0.55; 95% CI, -0.68 to -0.42; P < .001) and lower loop gain calculated during all sleep stages and all sleep positions (β = 0.19; 95% CI, 0.08-0.30; P < .001) were significant independent predictors of the apnea hypopnea index, with VpassiveAll being the most critical factor. In contrast, in POSA, collapsibility appeared to be less influential (β = -0.09; 95% CI, -0.21 to 0.03; P = .138). Nonanatomic endotypic characteristics (LGAll: β = 0.29; 95% CI, 0.18-0.41; P < .001; arousal threshold in all sleep stages and all sleep positions: β = 0.15; 95% CI, 0.01-0.28; P = .031; muscle compensation in all sleep stages and all sleep positions: β = -0.21; 95% CI, -0.29 to -0.12; P < .001) were significant in determining the severity of POSA, with loop gain being the most crucial factor. INTERPRETATION This study highlights the differences in endotypes between NPOSA and POSA. In Chinese individuals, anatomic factors were more significant in determining the severity of NPOSA, whereas nonanatomic traits were more likely to determine the severity of POSA. Future research should focus on developing personalized management strategies for individuals with NPOSA and POSA based on their endotypes. TRIAL REGISTRATION Chinese Clinical Trial Registry; No.: ChiCTR1900025714; URL: https://www.chictr.org.cn/indexEN.html.
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Affiliation(s)
- Xiaoting Wang
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China; Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Tianjiao Zhou
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China; Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Weijun Huang
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China; Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China.
| | - Jingyu Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China; Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Jianyin Zou
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China; Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Jian Guan
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China; Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
| | - Hongliang Yi
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China; Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China.
| | - Shankai Yin
- Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China; Otolaryngology Institute of Shanghai Jiao Tong University, Shanghai, China
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Ibrahim NA, Sankari A, Aldwaikat A, Pandya N, Chowdhuri S, Salloum A, Martin JL, Zeineddine S, Badr MS. Prevalence of central sleep apnea among veterans and response rate to continuous positive airway pressure therapy. SLEEP ADVANCES : A JOURNAL OF THE SLEEP RESEARCH SOCIETY 2024; 5:zpae011. [PMID: 38440255 PMCID: PMC10911693 DOI: 10.1093/sleepadvances/zpae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/11/2024] [Indexed: 03/06/2024]
Abstract
Study Objectives Sleep-disordered breathing (SDB) is common in the Veteran population. In this retrospective study, we investigated the prevalence of comorbid central and obstructive SDB and the response rate to PAP among Veterans. Methods Veterans were screened from a single VA medical center who had polysomnography (PSG) study from 2017 to 2021 to ascertain the presence, severity, and type of SDB by measuring the apnea-hypopnea index (AHI) and central apnea index (CAI). Patients were excluded if they did not have complete studies (diagnostic and PAP titration studies). The inclusion criteria for these analyses were central sleep apnea (CSA) defined as AHI ≥ 10 events/hour and CAI ≥ 5 events/hour. Diagnostic "CSA only" was defined as AHI ≥ 10 events/hour and CAI ≥ 50% of AHI. "OSA only" was defined if AHI ≥ 10 events/hour and CAI < 5 events/hour. Comorbid central and obstructive sleep apnea (COSA) was defined if AHI ≥ 10 events/hour and CAI > 5 events/hour but < 50% of AHI. The responsiveness to PAP therapy was determined based on the CAI < 5 events/hour on the titration study. Results A total of 90 patients met the inclusion criteria and from those 64 Veterans were found to have COSA (71%), 18 (20%) were CSA only, and 8 (9%) were OSA only. A total of 22 (24.4%) Veterans diagnosed with CSA or COSA were responsive to PAP therapy. Sixty days after treatment initiation, both responsive and nonresponsive groups had significant decreases in AHI and CAI (p < 0.05). Conclusions Comorbid central and obstructive SDB is common among Veterans. The response to PAP therapy is suboptimal but improves over time.
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Affiliation(s)
- Nesrine Adly Ibrahim
- Department of Medicine, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Internal Medicine, Wayne State University, Detroit, MI, USA
| | - Abdulghani Sankari
- Department of Medicine, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Internal Medicine, Wayne State University, Detroit, MI, USA
- Department of Medical Education, Ascension Providence Hospital, Southfield, MI, USA¸
| | - Ahmad Aldwaikat
- Department of Medicine, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Internal Medicine, Wayne State University, Detroit, MI, USA
| | - Nishtha Pandya
- Department of Medicine, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Internal Medicine, Wayne State University, Detroit, MI, USA
| | - Susmita Chowdhuri
- Department of Medicine, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Internal Medicine, Wayne State University, Detroit, MI, USA
| | - Anan Salloum
- Department of Medicine, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Internal Medicine, Wayne State University, Detroit, MI, USA
| | - Jennifer L Martin
- Department of Medicine, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
- Geriatric Research, Education and Clinical Center, VA Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Salam Zeineddine
- Department of Medicine, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Internal Medicine, Wayne State University, Detroit, MI, USA
| | - M Safwan Badr
- Department of Medicine, John D. Dingell VA Medical Center, Detroit, MI, USA
- Department of Internal Medicine, Wayne State University, Detroit, MI, USA
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Turnbull CD, Stradling JR. Endotyping, phenotyping and personalised therapy in obstructive sleep apnoea: are we there yet? Thorax 2023; 78:726-732. [PMID: 37217289 DOI: 10.1136/thorax-2023-220037] [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: 02/27/2023] [Accepted: 05/02/2023] [Indexed: 05/24/2023]
Abstract
Obstructive sleep apnoea (OSA) was traditionally thought to be mainly caused by obesity and upper airway crowding, and hence OSA management was not personalised according to particular characteristics, with most symptomatic patients receiving continuous positive airway pressure therapy. Recent advances in our understanding have identified additional potential and distinct causes of OSA (endotypes), and subgroups of patients (phenotypes) with increased risk of cardiovascular complications. In this review, we discuss the evidence to date as to whether there are distinct clinically useful endotypes and phenotypes of OSA, and the challenges to the field in moving towards delivering personalised therapy in OSA.
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Affiliation(s)
- Chris D Turnbull
- Oxford Centre for Respiratory Medicine, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Oxford Centre for Respiratory Medicine, NIHR Oxford Biomedical Research Centre, Oxford, UK
- NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
| | - John R Stradling
- NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
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Giannoni A, Borrelli C, Gentile F, Sciarrone P, Spießhöfer J, Piepoli M, Richerson GB, Floras JS, Coats AJS, Javaheri S, Emdin M, Passino C. Autonomic and respiratory consequences of altered chemoreflex function: clinical and therapeutic implications in cardiovascular diseases. Eur J Heart Fail 2023; 25:642-656. [PMID: 36907827 PMCID: PMC10989193 DOI: 10.1002/ejhf.2819] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 02/10/2023] [Accepted: 02/26/2023] [Indexed: 03/14/2023] Open
Abstract
The importance of chemoreflex function for cardiovascular health is increasingly recognized in clinical practice. The physiological function of the chemoreflex is to constantly adjust ventilation and circulatory control to match respiratory gases to metabolism. This is achieved in a highly integrated fashion with the baroreflex and the ergoreflex. The functionality of chemoreceptors is altered in cardiovascular diseases, causing unstable ventilation and apnoeas and promoting sympathovagal imbalance, and it is associated with arrhythmias and fatal cardiorespiratory events. In the last few years, opportunities to desensitize hyperactive chemoreceptors have emerged as potential options for treatment of hypertension and heart failure. This review summarizes up to date evidence of chemoreflex physiology/pathophysiology, highlighting the clinical significance of chemoreflex dysfunction, and lists the latest proof of concept studies based on modulation of the chemoreflex as a novel target in cardiovascular diseases.
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Affiliation(s)
- Alberto Giannoni
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana G. Monasterio, Pisa, Italy
| | | | - Francesco Gentile
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
| | | | - Jens Spießhöfer
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- University of Aachen, Aachen, Germany
| | | | | | - John S Floras
- Division of Cardiology, Mount Sinai Hospital, University of Toronto, Ontario, Canada
| | | | - Shahrokh Javaheri
- Division of Pulmonary and Sleep Medicine, Bethesda North Hospital, Cincinnati, Ohio, Division of Pulmonary, Critical Care and Sleep Medicine, University of Cincinnati, Cincinnati, Ohio, and Division of Cardiology, The Ohio State University, Columbus, Ohio USA
| | - Michele Emdin
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana G. Monasterio, Pisa, Italy
| | - Claudio Passino
- Health Science Interdisciplinary Center, Scuola Superiore Sant’Anna, Pisa, Italy
- Fondazione Toscana G. Monasterio, Pisa, Italy
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Ni YN, Thomas RJ. Predictors and consequences of residual apnea during positive airway pressure therapy. Sleep Med 2023; 106:42-51. [PMID: 37044000 DOI: 10.1016/j.sleep.2023.03.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/23/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023]
Abstract
STUDY OBJECTIVES Determine the risk factors for, and consequences of, residual apnea during long-term positive airway pressure (PAP) therapy for obstructive sleep apnea (OSA). METHODS A prospective cohort study of 195 subjects after a split-night polysomnogram. Estimation of residual respiratory events on PAP were done by both automated and manual scoring of data in EncoreAnywhere™. Clinical and polysomnographic predictors of residual apnea were estimated. RESULTS There were 166 and 101 patients still on PAP at the 3 and 12 months, respectively. Seventy four (44.6%) and 46 (45.5%) had a residual scored respiratory event index-flow (sREIFLOW) ≥ 15/hour of use and 46 (45.5%) at the 3rd and 12th month, respectively. Treatment phase central apnea hypopnea index (TCAHI), a surrogate of high loop gain, was the main predictor for residual sREIFLOW (β = 0.345, p: 0.025) at the 3rd and 12th month (β = 0.147, p: 0.020). TCAHI also predicted unstable breathing (U) %. The body mass index (hazard ratio [HR] 1.034, 95% CI 1.008-1.062, p: 0.012) and effective sREIFLOW>15/hour in the first month (HR 2.477, 95% CI 1.510-4.065, p < 0.001) were the key predictors for drop out of PAP use at the 12th month. Effective sREIFLOW>15/hour in the first month was also a predictor for median usage duration >4 h for 70% of the night at both the 3rd month (odds ratio [OR] 0.947, 95% CI 0.909-0.986, p: 0.008) and 12th month (OR 0.973, 95% CI 0.951-0.994, p: 0.014). CONCLUSIONS Treatment-phase CAHI predicts long-term residual apnea on PAP. High residual disease adversely impacts adherence.
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Dai L, Wang X, Xiao Y. Role of chemosensitivity: Possible pathophysiological mediator of obstructive sleep apnea and type 2 diabetes. Sleep Med 2023; 101:490-496. [PMID: 36527940 DOI: 10.1016/j.sleep.2022.12.004] [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: 10/08/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
Obstructive sleep apnea (OSA) and type 2 diabetes show some mutual promotion of disease development. Variation in chemosensitivity is a key contributor to the pathophysiological mechanisms causing OSA and type 2 diabetes. According to studies conducted thus far, people with OSA or type 2 diabetes may have higher chemoreflex levels, but it is challenging to identify the precise changes because of variations in participant characteristics, the severity of the disease at the time of recruitment, and the small sample sizes in each study. Lowering chemosensitivity may also be viewed as a new issue for individuals with OSA and type 2 diabetes who require personalized care. The purpose of this review was to give an overview of chemosensitivity changes in OSA and glucose metabolism, as well as prospective therapeutic treatments for patients with OSA and type 2 diabetes.
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Affiliation(s)
- Lu Dai
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Xiaona Wang
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Yi Xiao
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China.
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Zhang Z, Qi M, Hügli G, Khatami R. Quantitative Changes in Muscular and Capillary Oxygen Desaturation Measured by Optical Sensors during Continuous Positive Airway Pressure Titration for Obstructive Sleep Apnea. BIOSENSORS 2021; 12:bios12010003. [PMID: 35049631 PMCID: PMC8774245 DOI: 10.3390/bios12010003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/24/2021] [Accepted: 12/19/2021] [Indexed: 01/02/2023]
Abstract
Obstructive sleep apnea (OSA) is a common sleep disorder, and continuous positive airway pressure (CPAP) is the most effective treatment. Poor adherence is one of the major challenges in CPAP therapy. The recent boom of wearable optical sensors measuring oxygen saturation makes at-home multiple-night CPAP titrations possible, which may essentially improve the adherence of CPAP therapy by optimizing its pressure in a real-life setting economically. We tested whether the oxygen desaturations (ODs) measured in the arm muscle (arm_OD) by gold-standard frequency-domain multi-distance near-infrared spectroscopy (FDMD-NIRS) change quantitatively with titrated CPAP pressures in OSA patients together with polysomnography. We found that the arm_OD (2.08 ± 1.23%, mean ± standard deviation) was significantly smaller (p-value < 0.0001) than the fingertip OD (finger_OD) (4.46 ± 2.37%) measured by a polysomnography pulse oximeter. Linear mixed-effects models suggested that CPAP pressure was a significant predictor for finger_OD but not for arm_OD. Since FDMD-NIRS measures a mixture of arterial and venous OD, whereas a fingertip pulse oximeter measures arterial OD, our results of no association between arm_OD and finger_OD indicate that the arm_OD mainly represented venous desaturation. Arm_OD measured by optical sensors used for wearables may not be a suitable indicator of the CPAP titration effectiveness.
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Affiliation(s)
- Zhongxing Zhang
- Center for Sleep Medicine, Sleep Research and Epileptology, Clinic Barmelweid AG, 5017 Barmelweid, Switzerland; (M.Q.); (G.H.); (R.K.)
- Barmelweid Academy, Clinic Barmelweid AG, 5017 Barmelweid, Switzerland
- Correspondence:
| | - Ming Qi
- Center for Sleep Medicine, Sleep Research and Epileptology, Clinic Barmelweid AG, 5017 Barmelweid, Switzerland; (M.Q.); (G.H.); (R.K.)
| | - Gordana Hügli
- Center for Sleep Medicine, Sleep Research and Epileptology, Clinic Barmelweid AG, 5017 Barmelweid, Switzerland; (M.Q.); (G.H.); (R.K.)
| | - Ramin Khatami
- Center for Sleep Medicine, Sleep Research and Epileptology, Clinic Barmelweid AG, 5017 Barmelweid, Switzerland; (M.Q.); (G.H.); (R.K.)
- Barmelweid Academy, Clinic Barmelweid AG, 5017 Barmelweid, Switzerland
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
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Pun M, Beaudin AE, Raneri JK, Anderson TJ, Hanly PJ, Poulin MJ. Impact of nocturnal oxygen and CPAP on the ventilatory response to hypoxia in OSA patients free of overt cardiovascular disease. Exp Neurol 2021; 346:113852. [PMID: 34461058 DOI: 10.1016/j.expneurol.2021.113852] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 08/17/2021] [Accepted: 08/24/2021] [Indexed: 11/20/2022]
Abstract
A primary characteristic of obstructive sleep apnea (OSA) is chronic exposure to intermittent hypoxia (IH) due to repeated upper airway obstruction. Chronic IH exposure is believed to increase OSA severity over time by enhancing the acute ventilatory response to hypoxia (AHVR), thus promoting ventilatory overshoot when apnea ends and perpetuation of apnea during sleep. Continuous positive airway pressure (CPAP), the gold-standard treatment of OSA, reduces the AHVR, believed to result from correction of IH. However, CPAP also corrects ancillary features of OSA such as intermittent hypercapnia, negative intrathoracic pressure and surges in sympathetic activity, which may also contribute to the reduction in AHVR. Therefore, the objective of this study was to investigate the impact of nocturnal oxygen therapy (to remove IH only) and CPAP (to correct IH and ancillary features of OSA) on AHVR in newly diagnosed OSA patients. Fifty-two OSA patients and twenty-two controls were recruited. The AHVR was assessed using a 5 min iscopanic-hypoxic challenge before, and after, treatment of OSA by nocturnal oxygen therapy and CPAP. Following baseline measurements, OSA patients were randomly assigned to nocturnal oxygen therapy (Oxygen, n = 26) or no treatment (Air; n = 26). The AHVR was re-assessed following two weeks of oxygen therapy or no treatment, after which all patients were treated with CPAP. The AHVR was quantified following ~4 weeks of adherent CPAP therapy (n = 40). Both nocturnal oxygen and CPAP treatments improved hypoxemia (p < 0.05), and, as expected, nocturnal oxygen therapy did not completely abolish respiratory events (i.e., apneas/hypopneas). Averaged across all OSA patients, nocturnal oxygen therapy did not change AHVR from baseline to post-oxygen therapy. Similarly, the AHVR was not altered pre- and post-CPAP (p > 0.05). However, there was a significant decrease in AHVR with both nocturnal oxygen therapy and CPAP in patients in the highest OSA severity quartile (p < 0.05). Nocturnal oxygen therapy and CPAP both reduce the AHVR in patients with the most severe OSA. Therefore, IH appears to be the primary mechanism producing ventilatory instability in patients with severe OSA via enhancement of the AHVR.
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Affiliation(s)
- Matiram Pun
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Andrew E Beaudin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jill K Raneri
- Sleep Centre, Foothills Medical Centre, Calgary, AB, Canada
| | - Todd J Anderson
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Department of Cardiac Science, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Patrick J Hanly
- Sleep Centre, Foothills Medical Centre, Calgary, AB, Canada; Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
| | - Marc J Poulin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.
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Spiesshoefer J, Bannwitz B, Mohr M, Herkenrath S, Randerath W, Sciarrone P, Thiedemann C, Schneider H, Braun AT, Emdin M, Passino C, Dreher M, Boentert M, Giannoni A. Effects of nasal high flow on sympathovagal balance, sleep, and sleep-related breathing in patients with precapillary pulmonary hypertension. Sleep Breath 2021; 25:705-717. [PMID: 32827122 PMCID: PMC8195975 DOI: 10.1007/s11325-020-02159-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 07/09/2020] [Accepted: 08/01/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND In precapillary pulmonary hypertension (PH), nasal high flow therapy (NHF) may favorably alter sympathovagal balance (SVB) and sleep-related breathing through washout of anatomical dead space and alleviation of obstructive sleep apnea (OSA) due to generation of positive airway pressure. OBJECTIVES To investigate the effects of NHF on SVB, sleep, and OSA in patients with PH, and compare them with those of positive airway pressure therapy (PAP). METHODS Twelve patients with PH (Nice class I or IV) and confirmed OSA underwent full polysomnography, and noninvasive monitoring of SVB parameters (spectral analysis of heart rate, diastolic blood pressure variability). Study nights were randomly split into four 2-h segments with no treatment, PAP, NHF 20 L/min, or NHF 50 L/min. In-depth SVB analysis was conducted on 10-min epochs during daytime and stable N2 sleep at nighttime. RESULTS At daytime and compared with no treatment, NHF20 and NHF50 were associated with a flow-dependent increase in peripheral oxygen saturation but a shift in SVB towards increased sympathetic drive. At nighttime, NHF20 was associated with increased parasympathetic drive and improvements in sleep efficiency, but did not alter OSA severity. NHF50 was poorly tolerated. PAP therapy improved OSA but had heterogenous effects on SVB and neutral effects on sleep outcomes. Hemodynamic effects were neutral for all interventions. CONCLUSIONS In sleeping PH patients with OSA NHF20 but not NHF50 leads to decreased sympathetic drive likely due to washout of anatomical dead space. NHF was not effective in lowering the apnea-hypopnoea index and NHF50 was poorly tolerated.
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Affiliation(s)
- Jens Spiesshoefer
- Department of Neurology with Institute for Translational Neurology, University of Muenster, Muenster, Germany.
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, PI, Italy.
| | - Britta Bannwitz
- Department of Neurology with Institute for Translational Neurology, University of Muenster, Muenster, Germany
| | - Michael Mohr
- Department of Medicine A, Hematology, Oncology and Pulmonary Medicine, University Hospital Muenster, Muenster, Germany
| | - Simon Herkenrath
- Bethanien Hospital gGmbH Solingen, Solingen, Germany and Institute for Pneumology at the University of Cologne, Solingen, Germany
| | - Winfried Randerath
- Bethanien Hospital gGmbH Solingen, Solingen, Germany and Institute for Pneumology at the University of Cologne, Solingen, Germany
| | - Paolo Sciarrone
- Cardiology and Cardiovascular Medicine Division, Fondazione Toscana Gabriele Monasterio, National Research Council, CNR-Regione Toscana, Pisa, Italy
| | - Christian Thiedemann
- Department of Neurology with Institute for Translational Neurology, University of Muenster, Muenster, Germany
| | - Hartmut Schneider
- Sleep Disorders Center, Bayview Hospital, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Andrew T Braun
- Division of Allergy, Pulmonary and Critical Care, Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - Michele Emdin
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, PI, Italy
- Cardiology and Cardiovascular Medicine Division, Fondazione Toscana Gabriele Monasterio, National Research Council, CNR-Regione Toscana, Pisa, Italy
| | - Claudio Passino
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, PI, Italy
- Cardiology and Cardiovascular Medicine Division, Fondazione Toscana Gabriele Monasterio, National Research Council, CNR-Regione Toscana, Pisa, Italy
| | - Michael Dreher
- Department of Pneumology and Intensive Care Medicine, University Hospital RWTH, Aachen, Germany
| | - Matthias Boentert
- Department of Neurology with Institute for Translational Neurology, University of Muenster, Muenster, Germany
- Department of Medicine, UKM Marienhospital, Steinfurt, Germany
| | - Alberto Giannoni
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà, 33, 56127, Pisa, PI, Italy
- Cardiology and Cardiovascular Medicine Division, Fondazione Toscana Gabriele Monasterio, National Research Council, CNR-Regione Toscana, Pisa, Italy
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11
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The Mystery of Red Blood Cells Extracellular Vesicles in Sleep Apnea with Metabolic Dysfunction. Int J Mol Sci 2021; 22:ijms22094301. [PMID: 33919065 PMCID: PMC8122484 DOI: 10.3390/ijms22094301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/12/2022] Open
Abstract
Sleep is very important for overall health and quality of life, while sleep disorder has been associated with several human diseases, namely cardiovascular, metabolic, cognitive, and cancer-related alterations. Obstructive sleep apnea (OSA) is the most common respiratory sleep-disordered breathing, which is caused by the recurrent collapse of the upper airway during sleep. OSA has emerged as a major public health problem and increasing evidence suggests that untreated OSA can lead to the development of various diseases including neurodegenerative diseases. In addition, OSA may lead to decreased blood oxygenation and fragmentation of the sleep cycle. The formation of free radicals or reactive oxygen species (ROS) can emerge and react with nitric oxide (NO) to produce peroxynitrite, thereby diminishing the bioavailability of NO. Hypoxia, the hallmark of OSA, refers to a decline of tissue oxygen saturation and affects several types of cells, playing cell-to-cell communication a vital role in the outcome of this interplay. Red blood cells (RBCs) are considered transporters of oxygen and nutrients to the tissues, and these RBCs are important interorgan communication systems with additional functions, including participation in the control of systemic NO metabolism, redox regulation, blood rheology, and viscosity. RBCs have been shown to induce endothelial dysfunction and increase cardiac injury. The mechanistic links between changes of RBC functional properties and cardiovascular are largely unknown. Extracellular vesicles (EVs) are secreted by most cell types and released in biological fluids both under physiological and pathological conditions. EVs are involved in intercellular communication by transferring complex cargoes including proteins, lipids, and nucleic acids from donor cells to recipient cells. Advancing our knowledge about mechanisms of RBC-EVs formation and their pathophysiological relevance may help to shed light on circulating EVs and to translate their application to clinical practice. We will focus on the potential use of RBC-EVs as valuable diagnostic and prognostic biomarkers and state-specific cargoes, and possibilities as therapeutic vehicles for drug and gene delivery. The use of RBC-EVs as a precision medicine for the diagnosis and treatment of the patient with sleep disorder will improve the prognosis and the quality of life in patients with cardiovascular disease (CVD).
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12
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Selvadurai S, Benzon D, Voutsas G, Hamilton J, Yeh A, Cifra B, Narang I. Sleep-disordered breathing, respiratory patterns during wakefulness and functional capacity in pediatric patients with rapid-onset obesity with hypothalamic dysfunction, hypoventilation and autonomic dysregulation syndrome. Pediatr Pulmonol 2021; 56:479-485. [PMID: 33270379 DOI: 10.1002/ppul.25199] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 11/05/2020] [Accepted: 11/19/2020] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To characterize the clinical presentation of sleep-disordered breathing and respiratory patterns at rest and during a 6-min walk test (6MWT) in children with rapid-onset obesity, hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) syndrome. METHODS Retrospective study of children with ROHHAD who had a diagnostic baseline polysomnography, daytime cardiorespiratory monitoring at rest and a 6MWT. Polysomnography data were also compared with body mass index-, age-, and sex-matched controls. RESULTS Of the eight children with ROHHAD, all eight (100%) had obstructive sleep apnea (OSA) and 2/8 (25%) had nocturnal hypoventilation (NH) on their baseline polysomnography. Comparing the ROHHAD group to the control group, there were no significant differences in the median (interquartile range [IQR]) obstructive apnea-hypopnea index (11.1 [4.3-58.4] vs. 14.4 [10.3-23.3] events/h, respectively; p = .78). However, children with ROHHAD showed a significantly higher desaturation index compared to the control group (37.9 [13.7-59.8] vs. 14.7 [4.3-27.6] events/h; p = .05). While awake at rest, some children with ROHHAD experienced significant desaturations associated with central pauses. During the 6MWT, no significant desaturations were observed, but two children showed moderate functional limitation. CONCLUSIONS Among children with ROHHAD, respiratory instability may be demonstrated by a significant number and severity of oxygen desaturations during sleep in the presence of OSA, with or without NH, and oxygen desaturations with central pauses at rest during wakefulness. Interestingly, during daily activities that require submaximal effort, children may not experience oxygen desaturations. Early recognition of respiratory abnormalities and targeted therapeutic interventions are important to limit associated morbidity and mortality in ROHHAD.
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Affiliation(s)
- Sarah Selvadurai
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - David Benzon
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,McMaster University, Hamilton, Ontario, Canada
| | - Giorge Voutsas
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada
| | - Jill Hamilton
- University of Toronto, Toronto, Ontario, Canada.,Division of Endocrinology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ann Yeh
- University of Toronto, Toronto, Ontario, Canada.,Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Barbara Cifra
- University of Toronto, Toronto, Ontario, Canada.,Division of Cardiology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Indra Narang
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,University of Toronto, Toronto, Ontario, Canada.,Division of Respiratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
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13
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Bock JM, Hanson BE, Asama TF, Feider AJ, Hanada S, Aldrich AW, Dyken ME, Casey DP. Acute inorganic nitrate supplementation and the hypoxic ventilatory response in patients with obstructive sleep apnea. J Appl Physiol (1985) 2021; 130:87-95. [PMID: 33211592 DOI: 10.1152/japplphysiol.00696.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Patients with obstructive sleep apnea (OSA) have increased cardiovascular disease risk largely attributable to hypertension. Heightened peripheral chemoreflex sensitivity (i.e., exaggerated responsiveness to hypoxia) facilitates hypertension in these patients. Nitric oxide blunts the peripheral chemoreflex, and patients with OSA have reduced nitric oxide bioavailability. We therefore investigated the dose-dependent effects of acute inorganic nitrate supplementation (beetroot juice), an exogenous nitric oxide source, on blood pressure and cardiopulmonary responses to hypoxia in patients with OSA using a randomized, double-blind, placebo-controlled crossover design. Fourteen patients with OSA (53 ± 10 yr, 29.2 ± 5.8 kg/m2, apnea-hypopnea index = 17.8 ± 8.1, 43%F) completed three visits. Resting brachial blood pressure and cardiopulmonary responses to inspiratory hypoxia were measured before, and 2 h after, acute inorganic nitrate supplementation [∼0.10 mmol (placebo), 4.03 mmol (low dose), and 8.06 mmol (high dose)]. Placebo increased neither plasma [nitrate] (30 ± 52 to 52 ± 23 μM, P = 0.26) nor [nitrite] (266 ± 153 to 277 ± 164 nM, P = 0.21); however, both increased following low (29 ± 17 to 175 ± 42 μM, 220 ± 137 to 514 ± 352 nM) and high doses (26 ± 11 to 292 ± 90 μM, 248 ± 155 to 738 ± 427 nM, respectively, P < 0.01 for all). Following placebo, systolic blood pressure increased (120 ± 9 to 128 ± 10 mmHg, P < 0.05), whereas no changes were observed following low (121 ± 11 to 123 ± 8 mmHg, P = 0.19) or high doses (124 ± 13 to 124 ± 9 mmHg, P = 0.96). The peak ventilatory response to hypoxia increased following placebo (3.1 ± 1.2 to 4.4 ± 2.6 L/min, P < 0.01) but not low (4.4 ± 2.4 to 5.4 ± 3.4 L/min, P = 0.11) or high doses (4.3 ± 2.3 to 4.8 ± 2.7 L/min, P = 0.42). Inorganic nitrate did not change the heart rate responses to hypoxia (beverage-by-time P = 0.64). Acute inorganic nitrate supplementation appears to blunt an early-morning rise in systolic blood pressure potentially through suppression of peripheral chemoreflex sensitivity in patients with OSA.NEW & NOTEWORTHY The present study is the first to examine the acute effects of inorganic nitrate supplementation on resting blood pressure and cardiopulmonary responses to hypoxia (e.g., peripheral chemoreflex sensitivity) in patients with obstructive sleep apnea (OSA). Our data indicate inorganic nitrate supplementation attenuates an early-morning rise in systolic blood pressure potentially attributable to blunted peripheral chemoreflex sensitivity. These data show proof-of-concept that inorganic nitrate supplementation could reduce the risk of cardiovascular disease in patients with OSA.
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Affiliation(s)
- Joshua M Bock
- Department of Physical Therapy & Rehabilitation Science, University of Iowa, Iowa City, Iowa
| | - Brady E Hanson
- Department of Physical Therapy & Rehabilitation Science, University of Iowa, Iowa City, Iowa
| | - Thomas F Asama
- Department of Physical Therapy & Rehabilitation Science, University of Iowa, Iowa City, Iowa
| | - Andrew J Feider
- Department of Anesthesia, University of Iowa, Iowa City, Iowa
| | - Satoshi Hanada
- Department of Anesthesia, University of Iowa, Iowa City, Iowa
| | - Aric W Aldrich
- Department of Anesthesia, University of Iowa, Iowa City, Iowa
| | - Mark Eric Dyken
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Darren P Casey
- Department of Physical Therapy & Rehabilitation Science, University of Iowa, Iowa City, Iowa.,Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
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14
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Brackley AD, Andrade MA, Toney GM. Intermittent hypercapnic hypoxia induces respiratory hypersensitivity to fentanyl accompanied by tonic respiratory depression by endogenous opioids. J Physiol 2020; 598:3239-3257. [PMID: 32415789 PMCID: PMC8162062 DOI: 10.1113/jp280021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 05/07/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Sleep apnoea increases susceptibility to opioid-induced respiratory depression (OIRD). Endogenous opioids are implicated as a contributing factor in sleep apnoea. Rats exposed to sleep-phase chronic intermittent hypercapnic hypoxia (CIHH) for 7 days exhibited exaggerated OIRD to systemic fentanyl both while anaesthetized and artificially ventilated and while conscious and breathing spontaneously, implicating heightened CNS inhibitory efficacy of fentanyl. CIHH also induced tonic endogenous opioid suppression of neural inspiration. Sleep-related episodes of hypercapnic hypoxia, as in sleep apnoea, promote hypersensitivity to OIRD, with tonic respiratory depression by endogenous opioids implicated as a potential underlying cause. ABSTRACT Sleep apnoea (SA) increases opioid-induced respiratory depression (OIRD) and lethality. To test the hypothesis that this results from chronic intermittent bouts of hypercapnic hypoxia (CIHH) accompanying SA, we compared OIRD across continuously normoxic control rats and rats exposed to sleep-phase (8 h/day) CIHH for 1 week. OIRD sensitivity was first assessed in anaesthetized (urethane/α-chloralose), vagotomized and artificially ventilated rats by recording phrenic nerve activity (PNA) to index neural inspiration and quantify PNA burst inhibition to graded doses (0, 2, 20, 50 μg kg-1 , i.v.) of the synthetic opioid fentanyl. Fentanyl dose-dependently reduced PNA burst frequency (P = 0.0098-0.0001), while increasing the duration of burst quiescence at 50 μg kg-1 (P < 0.0001, n = 5-6/group/dose). CIHH shifted the fentanyl dose-phrenic burst frequency response curve to the left (P = 0.0163) and increased the duration of burst quiescence (P < 0.0001). During fentanyl recovery, PNA burst width was increased relative to baseline in normoxic and CIHH rats. Systemic naloxone (1 mg kg-1 , i.v.) reversed fentanyl-induced PNA arrest in both groups (P = 0.0002), and increased phrenic burst amplitude above baseline (P = 0.0113) in CIHH rats only. Differential sensitivity to anaesthesia as a cause of CIHH-related OIRD hypersensitivity was excluded by observing in conscious spontaneously breathing rats that fentanyl at 20 μg kg-1 (i.v.), which silenced PNA in anaesthetized rats, differentially increased breathing variability in normoxic versus CIHH rats (P = 0.0427), while significantly reducing breathing frequency (P < 0.0001) and periodicity (P = 0.0003) in CIHH rats only. Findings indicate that CIHH increased OIRD sensitivity, with tonic inspiratory depression by endogenous opioids as a likely contributing cause.
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Affiliation(s)
- Allison D Brackley
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229
- Center for Biomedical Neuroscience, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229
| | - Mary Ann Andrade
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229
| | - Glenn M Toney
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229
- Center for Biomedical Neuroscience, University of Texas Health San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229
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15
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Kim LJ, Polotsky VY. Carotid Body and Metabolic Syndrome: Mechanisms and Potential Therapeutic Targets. Int J Mol Sci 2020; 21:E5117. [PMID: 32698380 PMCID: PMC7404212 DOI: 10.3390/ijms21145117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/11/2020] [Accepted: 07/16/2020] [Indexed: 12/19/2022] Open
Abstract
The carotid body (CB) is responsible for the peripheral chemoreflex by sensing blood gases and pH. The CB also appears to act as a peripheral sensor of metabolites and hormones, regulating the metabolism. CB malfunction induces aberrant chemosensory responses that culminate in the tonic overactivation of the sympathetic nervous system. The sympatho-excitation evoked by CB may contribute to the pathogenesis of metabolic syndrome, inducing systemic hypertension, insulin resistance and sleep-disordered breathing. Several molecular pathways are involved in the modulation of CB activity, and their pharmacological manipulation may lead to overall benefits for cardiometabolic diseases. In this review, we will discuss the role of the CB in the regulation of metabolism and in the pathogenesis of the metabolic dysfunction induced by CB overactivity. We will also explore the potential pharmacological targets in the CB for the treatment of metabolic syndrome.
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Affiliation(s)
- Lenise J. Kim
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA;
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16
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Martinez D, Rogers RC, Hasser EM, Hermann GE, Kline DD. Loss of excitatory amino acid transporter restraint following chronic intermittent hypoxia contributes to synaptic alterations in nucleus tractus solitarii. J Neurophysiol 2020; 123:2122-2135. [PMID: 32347148 PMCID: PMC7311725 DOI: 10.1152/jn.00766.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Peripheral viscerosensory afferent signals are transmitted to the nucleus tractus solitarii (nTS) via release of glutamate. Following release, glutamate is removed from the extrasynaptic and synaptic cleft via excitatory amino acid transporters (EAATs), thus limiting glutamate receptor activation or over activation, and maintaining its working range. We have shown that EAAT block with the antagonist threo-β-benzyloxyaspartic acid (TBOA) depolarized nTS neurons and increased spontaneous excitatory postsynaptic current (sEPSC) frequency yet reduced the amplitude of afferent (TS)-evoked EPSCs (TS-EPSCs). Interestingly, chronic intermittent hypoxia (CIH), a model of obstructive sleep apnea (OSA), produces similar synaptic responses as EAAT block. We hypothesized EAAT expression or function are downregulated after CIH, and this reduction in glutamate removal contributes to the observed neurophysiological responses. To test this hypothesis, we used brain slice electrophysiology and imaging of glutamate release and TS-afferent Ca2+ to compare nTS properties of rats exposed to 10 days of normoxia (Norm; 21%O2) or CIH. Results show that EAAT blockade with (3S)-3-[[3-[[4-(trifluoromethyl)benzoyl]-amino]phenyl]methoxy]-l-aspartic acid (TFB-TBOA) in Norm caused neuronal depolarization, generation of an inward current, and increased spontaneous synaptic activity. The latter augmentation was eliminated by inclusion of tetrodotoxin in the perfusate. TS stimulation during TFB-TBOA also elevated extracellular glutamate and decreased presynaptic Ca2+ and TS-EPSC amplitude. In CIH, the effects of EAAT block are eliminated or attenuated. CIH reduced EAAT expression in nTS, which may contribute to the attenuated function seen in this condition. Therefore, CIH reduces EAAT influence on synaptic and neuronal activity, which may lead to the physiological consequences seen in OSA and CIH.NEW & NOTEWORTHY Removal of excitatory amino acid transporter (EAAT) restraint increases spontaneous synaptic activity yet decreases afferent [tractus solitarius (TS)]-driven excitatory postsynaptic current (EPSC) amplitude. In the chronic intermittent hypoxia model of obstructive sleep apnea, this restraint is lost due to reduction in EAAT expression and function. Thus EAATs are important in controlling elevated glutamatergic signaling, and loss of such control results in maladaptive synaptic signaling.
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Affiliation(s)
- Diana Martinez
- 1Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | | | - Eileen M. Hasser
- 1Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri,2Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | | | - David D. Kline
- 1Department of Biomedical Sciences and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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17
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Spicuzza L, Campisi R, Crimi C, Frasca E, Crimi N. Prevalence and determinants of co-morbidities in patients with obstructive apnea and chronic obstructive pulmonary disease. Eur J Intern Med 2019; 69:e15-e16. [PMID: 31494020 DOI: 10.1016/j.ejim.2019.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 08/21/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Lucia Spicuzza
- Respiratory Unit, A.O.U. Policlinico-Vittorio Emanuele, University of Catania, Italy.
| | - Raffaele Campisi
- Respiratory Unit, A.O.U. Policlinico-Vittorio Emanuele, University of Catania, Italy
| | - Claudia Crimi
- Respiratory Unit, A.O.U. Policlinico-Vittorio Emanuele, University of Catania, Italy
| | - Emilio Frasca
- Respiratory Unit, A.O.U. Policlinico-Vittorio Emanuele, University of Catania, Italy
| | - Nunzio Crimi
- Respiratory Unit, A.O.U. Policlinico-Vittorio Emanuele, University of Catania, Italy
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18
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Radovanovic D, Rizzi M, Airoldi A, Mantero M, Di Marco F, Raccanelli R, Santus P. Effect of continuous positive airway pressure on respiratory drive in patients with obstructive sleep apnea. Sleep Med 2019; 64:3-11. [PMID: 31655322 DOI: 10.1016/j.sleep.2019.05.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 05/03/2019] [Accepted: 05/06/2019] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Patients with obstructive sleep apnea (OSA) have an altered control of breathing during wakefulness. Thus far, whether and how treatment with continuous positive airway pressure (CPAP) may restore these abnormalities has been poorly understood. The aim of this study was to investigate the long-term effects of CPAP on the breathing pattern, ventilatory drive (VDr), and chemoreceptor sensitivity in OSA patients. PATIENTS AND METHODS This was a prospective, observational study, carried out in an academic sleep outpatient clinic. A total of 62 patients with OSA (mean age [SD], 51 [11] years) underwent polysomnography (PSG), breathing pattern assessment, mouth occlusion pressure, ventilatory response to hypoxemia (Ve/SaO2), and hypercapnia (Ve/PETCO2) before and after CPAP titration and during 12-month follow-up. A total of 48 age-matched healthy subjects served as controls. Patients with good (≥6 h/night) and poor (<6 h/night) compliance with CPAP were also compared. RESULTS At baseline, VDr as well as thoracic and inspiratory impedances were greater in patients with OSA compared with controls and were reduced by CPAP treatment, starting from the night of titration (P < 0.01), especially in patients with good compliance with CPAP. Baseline Ve/SaO2 was higher in OSA patients (P < 0.05) and was progressively normalized during CPAP treatment (P < 0.001). The pathophysiological changes were mainly due to a reduction in tidal volume. The remaining breathing pattern parameters were unaltered by CPAP treatment and were similar between groups. CONCLUSION In OSA patients, the mechanics of breathing are inefficient because of an imbalance of the VDr. Regular CPAP treatment improves the efficiency of the respiratory system and normalizes the hypoxemic stimulus.
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Affiliation(s)
- Dejan Radovanovic
- Division of Respiratory Diseases, Luigi Sacco University Hospital, Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, Milan, Italy
| | - Maurizio Rizzi
- Division of Respiratory Diseases, Luigi Sacco University Hospital, Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, Milan, Italy
| | - Andrea Airoldi
- Division of Respiratory Diseases, Luigi Sacco University Hospital, Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, Milan, Italy
| | - Marco Mantero
- Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy; Internal Medicine Department, Respiratory Unit and Regional Adult Cystic Fibrosis Center, IRCCS Fondazione Cá Granda Ospedale Policlinico, Milan, Italy
| | - Fabiano Di Marco
- Dipartimento di Scienze della Salute, Università degli Studi di Milano, Respiratory Unit, ASST - Ospedale Papa Giovanni XXIII, Bergamo, Italy
| | - Rita Raccanelli
- Cardiorespiratory Rehabilitation Medicine, IRCCS ICS Maugeri SPA SB, Milan, Italy
| | - Pierachille Santus
- Division of Respiratory Diseases, Luigi Sacco University Hospital, Department of Biomedical and Clinical Sciences (DIBIC), Università degli Studi di Milano, Milan, Italy.
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19
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Christensson E, Ebberyd A, Hårdemark Cedborg A, Lodenius Å, Österlund Modalen Å, Franklin KA, Eriksson LI, Jonsson Fagerlund M. Hypoxic ventilatory response after rocuronium‐induced partial neuromuscular blockade in men with obstructive sleep apnoea. Anaesthesia 2019; 75:338-347. [DOI: 10.1111/anae.14806] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2019] [Indexed: 12/12/2022]
Affiliation(s)
- E. Christensson
- Function Peri‐operative Medicine and Intensive Care Karolinska University Hospital Section for Anaesthesiology and Intensive Care Medicine Karolinska Institute StockholmSweden
- Department of Physiology and Pharmacology Section for Anaesthesiology and Intensive Care Medicine Karolinska Institute StockholmSweden
| | - A. Ebberyd
- Department of Physiology and Pharmacology Section for Anaesthesiology and Intensive Care Medicine Karolinska Institute StockholmSweden
| | - A. Hårdemark Cedborg
- Department of Physiology and Pharmacology Section for Anaesthesiology and Intensive Care Medicine Karolinska Institute StockholmSweden
| | - Å. Lodenius
- Department of Physiology and Pharmacology Section for Anaesthesiology and Intensive Care Medicine Karolinska Institute StockholmSweden
| | | | - K. A. Franklin
- Department of Surgical and Perioperative Sciences, Surgery Umeå University Umeå Sweden
| | - L. I. Eriksson
- Function Peri‐operative Medicine and Intensive Care Karolinska University Hospital Section for Anaesthesiology and Intensive Care Medicine Karolinska Institute StockholmSweden
- Department of Physiology and Pharmacology Section for Anaesthesiology and Intensive Care Medicine Karolinska Institute StockholmSweden
| | - M. Jonsson Fagerlund
- Function Peri‐operative Medicine and Intensive Care Karolinska University Hospital Section for Anaesthesiology and Intensive Care Medicine Karolinska Institute StockholmSweden
- Department of Physiology and Pharmacology Section for Anaesthesiology and Intensive Care Medicine Karolinska Institute StockholmSweden
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20
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Li Y, Ye J, Han D, Zhao D, Cao X, Orr J, Jen R, Deacon-Diaz N, Sands SA, Owens R, Malhotra A. The Effect of Upper Airway Surgery on Loop Gain in Obstructive Sleep Apnea. J Clin Sleep Med 2019; 15:907-913. [PMID: 31138381 DOI: 10.5664/jcsm.7848] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 02/18/2019] [Indexed: 12/28/2022]
Abstract
STUDY OBJECTIVES Controversy exists as to whether elevated loop gain is a cause or consequence of obstructive sleep apnea (OSA). Upper airway surgery is commonly performed in Asian patients with OSA who have failed positive airway pressure therapy and who are thought to have anatomical predisposition to OSA. We hypothesized that high loop gain would decrease following surgical treatment of OSA due to reduced sleep apnea severity. METHODS Polysomnography was performed preoperatively and postoperatively to assess OSA severity in 30 Chinese participants who underwent upper airway surgery. Loop gain was calculated using a validated clinically-applicable method by fitting a feedback control model to airflow. RESULTS Patients were followed up for a median (interquartile range) of 130 (62, 224) days after surgery. Apnea-hypopnea index (AHI) changed from 60.8 (33.7, 71.7) to 18.4 (9.9, 42.5) events/h (P < .001). Preoperative and postoperative loop gain was 0.70 (0.58, 0.80) and 0.53 (0.46, 0.63) respectively (P < .001). There was a positive association between the decrease in loop gain and the improvement of AHI (P = .025). CONCLUSIONS High loop gain was reduced by surgical treatment of OSA in our cohort. These data suggest that elevated loop gain may be acquired in OSA and may provide mechanistic insight into improvement in OSA with upper airway surgery. CLINICAL TRIAL REGISTRATION Registry: ClinicalTrials.gov, Title: The Impact of Sleep Apnea Treatment on Physiology Traits in Chinese Patients With Obstructive Sleep Apnea, Identifier: NCT02696629, URL: https://clinicaltrials.gov/show/NCT02696629.
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Affiliation(s)
- Yanru Li
- Department of Otolaryngology Head and Neck Surgery and Clinical Center for OSAHS, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China), Capital Medical University, Beijing, China.,Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, San Diego, California
| | - Jingying Ye
- Department of Otolaryngology Head and Neck Surgery and Clinical Center for OSAHS, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China), Capital Medical University, Beijing, China.,Department of Otolaryngology Head and Neck Surgery, Beijing Tsinghua Changgung Hospital, Beijing, China
| | - Demin Han
- Department of Otolaryngology Head and Neck Surgery and Clinical Center for OSAHS, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China), Capital Medical University, Beijing, China
| | - Di Zhao
- Department of Otolaryngology Head and Neck Surgery and Clinical Center for OSAHS, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China), Capital Medical University, Beijing, China
| | - Xin Cao
- Department of Otolaryngology Head and Neck Surgery and Clinical Center for OSAHS, Beijing Tongren Hospital, Capital Medical University, Beijing, China.,Key Laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education of China), Capital Medical University, Beijing, China.,Department of Otolaryngology Head and Neck Surgery, Beijing Tsinghua Changgung Hospital, Beijing, China
| | - Jeremy Orr
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, San Diego, California
| | - Rachel Jen
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, San Diego, California
| | - Naomi Deacon-Diaz
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, San Diego, California
| | - Scott A Sands
- Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Robert Owens
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, San Diego, California
| | - Atul Malhotra
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, San Diego, California
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21
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Deacon-Diaz N, Malhotra A. Inherent vs. Induced Loop Gain Abnormalities in Obstructive Sleep Apnea. Front Neurol 2018; 9:896. [PMID: 30450076 PMCID: PMC6224344 DOI: 10.3389/fneur.2018.00896] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 10/02/2018] [Indexed: 12/11/2022] Open
Abstract
Unstable ventilatory chemoreflex control, quantified as loop gain, is recognized as one of four key pathophysiological traits that contribute to cause obstructive sleep apnea (OSA). Novel treatments aimed at reducing loop gain are being investigated, with the intention that future OSA treatment may be tailored to the individual's specific cause of apnea. However, few studies have evaluated loop gain in OSA and non-OSA controls and those that have provide little evidence to support an inherent abnormality in either overall chemical loop gain in OSA patients vs. non-OSA controls, or its components (controller and plant gain). However, intermittent hypoxia may induce high controller gain through neuroplastic changes to chemoreflex control, and may also decrease plant gain via oxidative stress induced inflammation and reduced lung function. The inherent difficulties and limitations with loop gain measurements are discussed and areas where further research are required are highlighted, as only by understanding the mechanisms underlying OSA are new therapeutic approaches likely to emerge in OSA.
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Affiliation(s)
- Naomi Deacon-Diaz
- Department of Medicine, Pulmonary and Critical Care Medicine, University of California, San Diego, San Diego, CA, United States
| | - Atul Malhotra
- Department of Medicine, Pulmonary and Critical Care Medicine, University of California, San Diego, San Diego, CA, United States
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22
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Deacon-Diaz NL, Sands SA, McEvoy RD, Catcheside PG. Daytime loop gain is elevated in obstructive sleep apnea but not reduced by CPAP treatment. J Appl Physiol (1985) 2018; 125:1490-1497. [PMID: 30161007 DOI: 10.1152/japplphysiol.00175.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Reduced ventilatory control stability (elevated loop gain) is a key nonanatomical, pathological trait contributing to obstructive sleep apnea (OSA), yet the mechanisms responsible remain unclear. We sought to identify the key factors contributing to elevated loop gain in OSA (controller vs. plant contributions) and to examine whether abnormalities in these factors persist after OSA treatment. In 15 males (8 OSA, 7 height, weight- and age -matched controls), we measured loop gain, controller gain, and plant gain using a pseudorandom binary CO2 stimulation method during wakefulness. Factors potentially influencing plant gain were also assessed (supine lung volume via helium dilution and spirometry). Measures were repeated 2 and 6 wk after initiating continuous positive airway pressure treatment. Loop gain (LG) was higher in OSA versus controls (LG at 1 cycle/min 0.28 ± 0.04 vs. 0.16 ± 0.04, P = 0.046, respectively), and the controller exhibited a greater peak response to CO2 and faster roll-off in OSA. OSA patients also exhibited reduced forced expiratory volume in the first second and forced vital capacity compared with controls (92.2 ± 1.7 vs. 102.9 ± 3.5% predicted, P = 0.021; 93.4 ± 3.1 vs. 106.6 ± 3.6% predicted, P = 0.015, respectively). There was no effect of treatment on any variable. These findings confirm loop gain is higher in untreated OSA patients than in matched controls; however, this was not affected by treatment. NEW & NOTEWORTHY Elevated loop gain contributes to obstructive sleep apnea (OSA) pathophysiology. However, whether loop gain is inherently elevated in OSA or induced by OSA itself, whether it is elevated due to increased chemoreflex sensitivity or obesity-dependent reduced lung volume, and whether it is treatment reversible, are all currently uncertain. This study found loop gain was elevated in OSA versus age-, sex-, height-, and weight-matched controls. However, this was not altered by 6-wk continuous positive airway pressure treatment.
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Affiliation(s)
- Naomi Louise Deacon-Diaz
- Discipline of Physiology, School of Medical Sciences, University of Adelaide , Adelaide, South Australia , Australia.,Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia
| | - Scott A Sands
- Division of Sleep Medicine, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School , Boston, Massachusetts
| | - R Doug McEvoy
- Discipline of Physiology, School of Medical Sciences, University of Adelaide , Adelaide, South Australia , Australia.,Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia.,College of Medicine, Flinders University , Bedford Park, South Australia , Australia
| | - Peter G Catcheside
- Discipline of Physiology, School of Medical Sciences, University of Adelaide , Adelaide, South Australia , Australia.,Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia.,College of Medicine, Flinders University , Bedford Park, South Australia , Australia
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23
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Roy A, Farnham MMJ, Derakhshan F, Pilowsky PM, Wilson RJA. Acute intermittent hypoxia with concurrent hypercapnia evokes P2X and TRPV1 receptor-dependent sensory long-term facilitation in naïve carotid bodies. J Physiol 2018; 596:3149-3169. [PMID: 29159869 PMCID: PMC6068228 DOI: 10.1113/jp275001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 11/16/2017] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Activity-dependent plasticity can be induced in carotid body (CB) chemosensory afferents without chronic intermittent hypoxia (CIH) preconditioning by acute intermittent hypoxia coincident with bouts of hypercapnia (AIH-Hc). Several properties of this acute plasticity are shared with CIH-dependent sensory long-term facilitation (LTF) in that induction is dependent on 5-HT, angiotensin II, protein kinase C and reactive oxygen species. Several properties differ from CIH-dependent sensory LTF; H2 O2 appears to play no part in induction, whereas maintenance requires purinergic P2X2/3 receptor activation and is dependent on transient receptor potential vanilloid type 1 (TRPV1) receptor sensitization. Because P2X2/3 and TRPV1 receptors are located in carotid sinus nerve (CSN) terminals but not presynaptic glomus cells, a primary site of the acute AIH-Hc induced sensory LTF appears to be postsynaptic. Our results obtained in vivo suggest a role for TRPV1-dependent CB activity in acute sympathetic LTF. We propose that P2X-TRPV1-receptor-dependent sensory LTF may constitute an important early mechanism linking sleep apnoea with hypertension and/or cardiovascular disease. ABSTRACT Apnoeas constitute an acute existential threat to neonates and adults. In large part, this threat is detected by the carotid bodies, which are the primary peripheral chemoreceptors, and is combatted by arousal and acute cardiorespiratory responses, including increased sympathetic output. Similar responses occur with repeated apnoeas but they continue beyond the last apnoea and can persist for hours [i.e. ventilatory and sympathetic long-term facilitation (LTF)]. These long-term effects may be adaptive during acute episodic apnoea, although they may prolong hypertension causing chronic cardiovascular impairment. We report a novel mechanism of acute carotid body (CB) plasticity (sensory LTF) induced by repeated apnoea-like stimuli [i.e. acute intermittent hypoxia coincident with bouts of hypercapnia (AIH-Hc)]. This plasticity did not require chronic intermittent hypoxia preconditioning, was dependent on P2X receptors and protein kinase C, and involved heat-sensitive transient receptor potential vanilloid type 1 (TRPV1) receptors. Reactive oxygen species (O2 ·¯) were involved in initiating plasticity only; no evidence was found for H2 O2 involvement. Angiotensin II and 5-HT receptor antagonists, losartan and ketanserin, severely reduced CB responses to individual hypoxic-hypercapnic challenges and prevented the induction of sensory LTF but, if applied after AIH-Hc, failed to reduce plasticity-associated activity. Conversely, TRPV1 receptor antagonism had no effect on responses to individual hypoxic-hypercapnic challenges but reduced plasticity-associated activity by ∼50%. Further, TRPV1 receptor antagonism in vivo reduced sympathetic LTF caused by AIH-Hc, although only if the CBs were functional. These data demonstrate a new mechanism of CB plasticity and suggest P2X-TRPV1-dependent sensory LTF as a novel target for pharmacological intervention in some forms of neurogenic hypertension associated with recurrent apnoeas.
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Affiliation(s)
- Arijit Roy
- Department of Physiology & Pharmacology, Hotchkiss Brain Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | | | - Fatemeh Derakhshan
- Department of Physiology & Pharmacology, Hotchkiss Brain Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | | | - Richard J. A. Wilson
- Department of Physiology & Pharmacology, Hotchkiss Brain Institute, Faculty of MedicineUniversity of CalgaryCalgaryAlbertaCanada
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24
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Deacon NL, McEvoy RD, Stadler DL, Catcheside PG. Intermittent hypercapnic hypoxia during sleep does not induce ventilatory long-term facilitation in healthy males. J Appl Physiol (1985) 2017; 123:534-543. [DOI: 10.1152/japplphysiol.01005.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 06/13/2017] [Accepted: 06/13/2017] [Indexed: 11/22/2022] Open
Abstract
Intermittent hypoxia-induced ventilatory neuroplasticity is likely important in obstructive sleep apnea pathophysiology. Although concomitant CO2levels and arousal state critically influence neuroplastic effects of intermittent hypoxia, no studies have investigated intermittent hypercapnic hypoxia effects during sleep in humans. Thus the purpose of this study was to investigate if intermittent hypercapnic hypoxia during sleep induces neuroplasticity (ventilatory long-term facilitation and increased chemoreflex responsiveness) in humans. Twelve healthy males were exposed to intermittent hypercapnic hypoxia (24 × 30 s episodes of 3% CO2and 3.0 ± 0.2% O2) and intermittent medical air during sleep after 2 wk washout period in a randomized crossover study design. Minute ventilation, end-tidal CO2, O2saturation, breath timing, upper airway resistance, and genioglossal and diaphragm electromyograms were examined during 10 min of stable stage 2 sleep preceding gas exposure, during gas and intervening room air periods, and throughout 1 h of room air recovery. There were no significant differences between conditions across time to indicate long-term facilitation of ventilation, genioglossal or diaphragm electromyogram activity, and no change in ventilatory response from the first to last gas exposure to suggest any change in chemoreflex responsiveness. These findings contrast with previous intermittent hypoxia studies without intermittent hypercapnia and suggest that the more relevant gas disturbance stimulus of concomitant intermittent hypercapnia frequently occurring in sleep apnea influences acute neuroplastic effects of intermittent hypoxia. These findings highlight the need for further studies of intermittent hypercapnic hypoxia during sleep to clarify the role of ventilatory neuroplasticity in the pathophysiology of sleep apnea.NEW & NOTEWORTHY Both arousal state and concomitant CO2levels are known modulators of the effects of intermittent hypoxia on ventilatory neuroplasticity. This is the first study to investigate the effects of combined intermittent hypercapnic hypoxia during sleep in humans. The lack of neuroplastic effects suggests a need for further studies more closely replicating obstructive sleep apnea to determine the pathophysiological relevance of intermittent hypoxia-induced ventilatory neuroplasticity.
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Affiliation(s)
- Naomi L. Deacon
- Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia; and
| | - R. Doug McEvoy
- Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia; and
- School of Medicine, Flinders University, Bedford Park, South Australia, Australia
| | - Daniel L. Stadler
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia; and
| | - Peter G. Catcheside
- Discipline of Physiology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia, Australia
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Repatriation General Hospital, Daw Park, South Australia, Australia; and
- School of Medicine, Flinders University, Bedford Park, South Australia, Australia
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25
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Abstract
Autonomic dysfunction is a frequent and relevant complication of diabetes mellitus, as it is associated with increased morbidity and mortality. In addition, it is today considered as predictive of the most severe diabetic complications, like nephropathy and retinopathy. The classical methods of screening are the cardiovascular reflex tests and were originally interpreted as evidence of nerve damage. A more modern approach, based on the integrated control of cardiovascular and respiratory function, reveals that these abnormalities are to a great extent functional, at least in the early stage of the disease, thus suggesting new potential interventions. Therefore, this review aims to go further investigating how the imbalance of the autonomic nervous system is altered and can be influenced in many chronic pathologies through a global view of cardio-respiratory and metabolic interactions and how the same mechanisms are applicable to diabetes.
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Affiliation(s)
- Luciano Bernardi
- Folkhälsan Institute of Genetics, Folkhälsan Research Center, University of Helsinki, Helsinki, Finland.
- Research Program Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland.
- , Villaggio dei Pioppi 2, 27020, Torre d'Isola, Italy.
| | - Lucio Bianchi
- Department of Endocrinology-Diabetology-Nutrition, Jean Verdier Hospital, AP-HP, CRNH-IdF, Paris-Nord University, Bondy, France
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26
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Treatment of Obstructive Sleep Apnea. Prospects for Personalized Combined Modality Therapy. Ann Am Thorac Soc 2016; 13:101-8. [PMID: 26569377 DOI: 10.1513/annalsats.201508-537fr] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Obstructive sleep apnea (OSA) is a common sleep disorder with serious associated morbidities. Although several treatment options are currently available, variable efficacy and adherence result in many patients either not being treated or receiving inadequate treatment long term. Personalized treatment based on relevant patient characteristics may improve adherence to treatment and long-term clinical outcomes. Four key traits of upper airway anatomy and neuromuscular control interact to varying degrees within individuals to cause OSA. These are: (1) the pharyngeal critical closing pressure, (2) the stability of ventilator chemoreflex feedback control (loop gain), (3) the negative intraesophageal pressure that triggers arousal (arousal threshold), and (4) the level of stimulus required to activated upper airway dilator muscles (upper airway recruitment threshold). Simplified diagnostic methods are being developed to assess these pathophysiological traits, potentially allowing prediction of which treatment would best suit each patient. In contrast to current practice of using various treatment modes alone, model predictions and pilot clinical trials show improved outcomes by combining several treatments targeted to each patient's pathophysiology profile. These developments could theoretically improve efficacy and adherence to treatment and in turn reduce the social and economic health burden of OSA and the associated life-threatening morbidities. This article reviews OSA pathophysiology and identifies currently available and investigational treatments that may be combined in the future to optimize therapy based on individual profiles of key patient pathophysiological traits.
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27
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Rotenberg BW, Murariu D, Pang KP. Trends in CPAP adherence over twenty years of data collection: a flattened curve. J Otolaryngol Head Neck Surg 2016; 45:43. [PMID: 27542595 PMCID: PMC4992257 DOI: 10.1186/s40463-016-0156-0] [Citation(s) in RCA: 412] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/11/2016] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Obstructive sleep apnea (OSA) is a common disorder, and continuous airway positive pressure (CPAP) is considered to be the gold standard of therapy. CPAP however is known to have problems with adherence, with many patients eventually abandoning the device. The purpose of this paper is to assess secular trends in CPAP adherence over the long term to see if there have been meaningful improvements in adherence in light of the multiple interventions proposed to do so. METHODS A comprehensive systematic literature review was conducted using the Medline-Ovid, Embase, and Pubmed databases, searching for data regarding CPAP adherence over a twenty year timeframe (1994-2015). Data was assessed for quality and then extracted. The main outcome measure was reported CPAP non-adherence. Secondary outcomes included changes in CPAP non-adherence when comparing short versus long-term, and changes in terms of behavioral counseling. RESULTS Eighty-two papers met study inclusion/exclusion criteria. The overall CPAP non-adherence rate based on a 7-h/night sleep time that was reported in studies conducted over the twenty year time frame was 34.1 %. There was no significant improvement over the time frame. Behavioral intervention improved adherence rates by ~1 h per night on average. CONCLUSIONS The rate of CPAP adherence remains persistently low over twenty years worth of reported data. No clinically significant improvement in CPAP adherence was seen even in recent years despite efforts toward behavioral intervention and patient coaching. This low rate of adherence is problematic, and calls into question the concept of CPAP as gold-standard of therapy for OSA.
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Affiliation(s)
- Brian W Rotenberg
- Department of Otolaryngology - Head and Neck Surgery, Western University, London, ON, Canada
| | - Dorian Murariu
- Department of Otolaryngology - Head and Neck Surgery, Western University, London, ON, Canada
| | - Kenny P Pang
- Asia Sleep Centre, Paragon, 290, Orchard Road, Unit 18-04, Singapore, 238859, Singapore.
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28
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Affiliation(s)
- Julian F R Paton
- School of Physiology, Pharmacology, and Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom.
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29
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Iftikhar IH, Bittencourt L, Youngstedt SD, Ayas N, Cistulli P, Schwab R, Durkin MW, Magalang UJ. Comparative efficacy of CPAP, MADs, exercise-training, and dietary weight loss for sleep apnea: a network meta-analysis. Sleep Med 2016; 30:7-14. [PMID: 28215266 DOI: 10.1016/j.sleep.2016.06.001] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/30/2016] [Accepted: 06/13/2016] [Indexed: 01/18/2023]
Abstract
STUDY OBJECTIVE To synthesize evidence from available studies on the relative efficacies of continuous positive airway pressure (CPAP), mandibular advancement device (MAD), supervised aerobic exercise training, and dietary weight loss in patients with obstructive sleep apnea (OSA). DESIGN Network meta-analysis of 80 randomized controlled trials (RCTs) short-listed from PubMed, SCOPUS, Web of science, and Cochrane register (inception - September 8, 2015). PATIENTS Individuals with OSA. INTERVENTIONS CPAP, MADs, exercise training, and dietary weight loss. RESULTS CPAP decreased apnea-hypopnea index (AHI) the most [by 25.27 events/hour (22.03-28.52)] followed by exercise training, MADs, and dietary weight loss. While the difference between exercise training and CPAP was non-significant [-8.04 (-17.00 to 0.92), a significant difference was found between CPAP and MADs on AHI and oxygen desaturation index (ODI) [-10.06 (-14.21 to -5.91) and -7.82 (-13.04 to -2.59), respectively]. Exercise training significantly improved Epworth sleepiness scores (ESS) [by 3.08 (0.68-5.48)], albeit with a non-significant difference compared to MADs and CPAP. CONCLUSIONS CPAP is the most efficacious in complete resolution of sleep apnea and in improving the indices of saturation during sleep. While MADs offer a reasonable alternative to CPAP, exercise training which significantly improved daytime sleepiness (ESS) could be used as adjunctive to the former two.
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Affiliation(s)
- Imran H Iftikhar
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Emory University, Atlanta, GA, USA.
| | - Lia Bittencourt
- Departmento de Psicobiologia, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Shawn D Youngstedt
- College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, USA
| | - Najib Ayas
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter Cistulli
- Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, and Sydney Medical School, University of Sydney, Australia
| | - Richard Schwab
- Department of Medicine, Division of Sleep Medicine, Pulmonary, Allergy and Critical Care, University of Pennsylvania Medical Center, Philadelphia, PA, USA
| | - Martin W Durkin
- Department of Clinical Research, Palmetto Health Richland, Columbia, SC, USA
| | - Ulysses J Magalang
- Division of Pulmonary, Allergy, Critical care & Sleep Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
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30
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Sharples LD, Clutterbuck-James AL, Glover MJ, Bennett MS, Chadwick R, Pittman MA, Quinnell TG. Meta-analysis of randomised controlled trials of oral mandibular advancement devices and continuous positive airway pressure for obstructive sleep apnoea-hypopnoea. Sleep Med Rev 2016; 27:108-24. [PMID: 26163056 PMCID: PMC5378304 DOI: 10.1016/j.smrv.2015.05.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 04/17/2015] [Accepted: 05/15/2015] [Indexed: 02/01/2023]
Abstract
Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness, impairs quality-of-life, and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment and mandibular advancement devices (MAD) have been shown to be effective in individual trials but their effectiveness particularly relative to disease severity is unclear. A MEDLINE, Embase and Science Citation Index search updating two systematic reviews to August 2013 identified 77 RCTs in adult OSAH patients comparing: MAD with conservative management (CM); MAD with CPAP; or CPAP with CM. Overall MAD and CPAP significantly improved apnoea-hypopnoea index (AHI) (MAD -9.3/hr (p < 0.001), CPAP -25.4 (p < 0.001)). In direct comparisons mean AHI and Epworth sleepiness scale score were lower (7.0/hr (p < 0.001) and 0.67 (p = 0.093) respectively) for CPAP. There were no CPAP vs. MAD trials in mild OSAH but in comparisons with CM, MAD and CPAP reduced ESS similarly (MAD 2.01 (p < 0.001); CPAP 1.23 (p = 0.012). Both MAD and CPAP are clinically effective in the treatment of OSAH. Although CPAP has a greater treatment effect, MAD is an appropriate treatment for patients who are intolerant of CPAP and may be comparable to CPAP in mild disease.
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Affiliation(s)
- Linda D Sharples
- University of Leeds Clinical Trials Research Unit, Leeds, United Kingdom; Medical Research Council Biostatistics Unit, Cambridge, United Kingdom.
| | | | - Matthew J Glover
- Health Economics Research Unit, Brunel University, Uxbridge, Middlesex, United Kingdom
| | - Maxine S Bennett
- Medical Research Council Biostatistics Unit, Cambridge, United Kingdom
| | - Rebecca Chadwick
- University Hospitals Coventry and Warwickshire NHS Trust, Coventry, United Kingdom
| | - Marcus A Pittman
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, United Kingdom
| | - Timothy G Quinnell
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, United Kingdom
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31
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Rotenberg BW, Vicini C, Pang EB, Pang KP. Reconsidering first-line treatment for obstructive sleep apnea: a systematic review of the literature. J Otolaryngol Head Neck Surg 2016; 45:23. [PMID: 27048606 PMCID: PMC4822285 DOI: 10.1186/s40463-016-0136-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 03/30/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Continuous positive airway pressure (CPAP) is typically recommended as first line therapy for obstructive sleep apnea, but the adherence rate of CPAP is problematic. This study's objective was to systematically review the literature relating to CPAP as first line therapy for OSA and compare it to surgical literature on the same topic. METHODS A systematic review was conducted according to PRISMA guidelines, examining Medline-Ovid, Embase, and Pubmed databases. The primary search objective was to identify all papers reporting the results of (1) randomized clinical trials (RCT) of CPAP for the treatment of adults with OSA; and (2) both randomized and non-randomized clinical trials and case series on the surgical treatment of OSA in adults. A PhD-level biostatistician first screened papers, and then those that met study criteria were retrieved and analyzed using standardized forms for each author. The primary outcomes were adherence rates of CPAP. RESULTS A total of 82 controlled clinical trials for CPAP and 69 controlled and non-controlled surgery trials were identified for analysis. Variation in CPAP use within reported RCT trials were identified, and the majority of patients in the studies would eventually be considered non-adherent to CPAP. CONCLUSIONS When considering the numerous patient-related factors that come into play when CPAP is prescribed, the concept of CPAP as gold-standard therapy for OSA should be reconsidered. In many cases surgery can provide a better overall outcome. This study's results suggest that certain patients with OSA may be managed more effectively with surgery than CPAP, without confounding issues of treatment adherence.
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Affiliation(s)
- Brian W Rotenberg
- Department of Otolaryngology-Head and Neck Surgery, Western University, London, Ontario, Canada. .,St. Joseph's Hospital, Room B2-501, 268 Grosvenor Street, London, ON, N6A 4V2, Canada.
| | - Claudio Vicini
- Head & Neck Department, ASL of Romagna, ENT and Oral Surgery Unit, Morgagni-Pierantoni Hospital (Forlì), Ospedale degli Infermi (Faenza), Forlì, Italy
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The role of high loop gain induced by intermittent hypoxia in the pathophysiology of obstructive sleep apnoea. Sleep Med Rev 2015; 22:3-14. [DOI: 10.1016/j.smrv.2014.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 10/03/2014] [Accepted: 10/07/2014] [Indexed: 02/06/2023]
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Sharples L, Glover M, Clutterbuck-James A, Bennett M, Jordan J, Chadwick R, Pittman M, East C, Cameron M, Davies M, Oscroft N, Smith I, Morrell M, Fox-Rushby J, Quinnell T. Clinical effectiveness and cost-effectiveness results from the randomised controlled Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and long-term economic analysis of oral devices and continuous positive airway pressure. Health Technol Assess 2015; 18:1-296. [PMID: 25359435 DOI: 10.3310/hta18670] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness (EDS), impairs quality of life (QoL) and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment is clinically effective but undermined by intolerance, and its cost-effectiveness is borderline in milder cases. Mandibular advancement devices (MADs) are another option, but evidence is lacking regarding their clinical effectiveness and cost-effectiveness in milder disease. OBJECTIVES (1) Conduct a randomised controlled trial (RCT) examining the clinical effectiveness and cost-effectiveness of MADs against no treatment in mild to moderate OSAH. (2) Update systematic reviews and an existing health economic decision model with data from the Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and newly published results to better inform long-term clinical effectiveness and cost-effectiveness of MADs and CPAP in mild to moderate OSAH. TOMADO A crossover RCT comparing clinical effectiveness and cost-effectiveness of three MADs: self-moulded [SleepPro 1™ (SP1); Meditas Ltd, Winchester, UK]; semibespoke [SleepPro 2™ (SP2); Meditas Ltd, Winchester, UK]; and fully bespoke [bespoke MAD (bMAD); NHS Oral-Maxillofacial Laboratory, Addenbrooke's Hospital, Cambridge, UK] against no treatment, in 90 adults with mild to moderate OSAH. All devices improved primary outcome [apnoea-hypopnoea index (AHI)] compared with no treatment: relative risk 0.74 [95% confidence interval (CI) 0.62 to 0.89] for SP1; relative risk 0.67 (95% CI 0.59 to 0.76) for SP2; and relative risk 0.64 (95% CI 0.55 to 0.76) for bMAD (p < 0.001). Differences between MADs were not significant. Sleepiness [as measured by the Epworth Sleepiness Scale (ESS)] was scored 1.51 [95% CI 0.73 to 2.29 (SP1)] to 2.37 [95% CI 1.53 to 3.22 (bMAD)] lower than no treatment (p < 0.001), with SP2 and bMAD significantly better than SP1. All MADs improved disease-specific QoL. Compliance was lower for SP1, which was unpopular at trial exit. At 4 weeks, all devices were cost-effective at £20,000/quality-adjusted life-year (QALY), with SP2 the best value below £39,800/QALY. META-ANALYSIS A MEDLINE, EMBASE and Science Citation Index search updating two existing systematic reviews (one from November 2006 and the other from June 2008) to August 2013 identified 77 RCTs in adult OSAH patients comparing MAD with conservative management (CM), MADs with CPAP or CPAP with CM. MADs and CPAP significantly improved AHI [MAD -9.3/hour (p < 0.001); CPAP -25.4/hour (p < 0.001)]. Effect difference between CPAP and MADs was 7.0/hour (p < 0.001), favouring CPAP. No trials compared CPAP with MADs in mild OSAH. MAD and CPAP reduced the ESS score similarly [MAD 1.6 (p < 0.001); CPAP 1.6 (p < 0.001)]. LONG-TERM COST-EFFECTIVENESS An existing model assessed lifetime cost-utility of MAD and CPAP in mild to moderate OSAH, using the revised meta-analysis to update input values. The TOMADO provided utility estimates, mapping ESS score to European Quality of Life-5 Dimensions three-level version for device cost-utility. Using SP2 as the standard device, MADs produced higher mean costs and mean QALYs than CM [incremental cost-effectiveness ratio (ICER) £6687/QALY]. From a willingness to pay (WTP) of £15,367/QALY, CPAP is cost-effective, although the likelihood of MADs (p = 0.48) and CPAP (p = 0.49) being cost-effective is very similar. Both were better than CM, but there was much uncertainty in the choice between CPAP and MAD (at a WTP £20,000/QALY, the probability of being the most cost-effective was 47% for MAD and 52% for CPAP). When SP2 lifespan increased to 18 months, the ICER for CPAP compared with MAD became £44,066. The ICER for SP1 compared with CM was £1552, and for bMAD compared with CM the ICER was £13,836. The ICER for CPAP compared with SP1 was £89,182, but CPAP produced lower mean costs and higher mean QALYs than bMAD. Differential compliance rates for CPAP reduces cost-effectiveness so MADs become less costly and more clinically effective with CPAP compliance 90% of SP2. CONCLUSIONS Mandibular advancement devices are clinically effective and cost-effective in mild to moderate OSAH. A semi-bespoke MAD is the appropriate first choice in most patients in the short term. Future work should explore whether or not adjustable MADs give additional clinical and cost benefits. Further data on longer-term cardiovascular risk and its risk factors would reduce uncertainty in the health economic model and improve precision of effectiveness estimates. TRIAL REGISTRATION This trial is registered as ISRCTN02309506. FUNDING This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 67. See the NIHR Journals Library website for further project information.
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Affiliation(s)
- Linda Sharples
- University of Leeds Clinical Trials Research Unit, Leeds, UK
| | - Matthew Glover
- Health Economics Research Unit, Brunel University, Uxbridge, UK
| | | | - Maxine Bennett
- Medical Research Council Biostatistics Unit, Cambridge, UK
| | - Jake Jordan
- Health Economics Research Unit, Brunel University, Uxbridge, UK
| | - Rebecca Chadwick
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, UK
| | - Marcus Pittman
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, UK
| | - Clare East
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, UK
| | - Malcolm Cameron
- Maxillofacial Unit, Addenbrooke's NHS Foundation Trust, Cambridge, UK
| | - Mike Davies
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, UK
| | - Nick Oscroft
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, UK
| | - Ian Smith
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, UK
| | - Mary Morrell
- National Heart and Lung Institute, Imperial College London, London, UK
| | | | - Timothy Quinnell
- Papworth Hospital NHS Foundation Trust, Papworth Everard, Cambridge, UK
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Marcus NJ, Del Rio R, Schultz HD. Central role of carotid body chemoreceptors in disordered breathing and cardiorenal dysfunction in chronic heart failure. Front Physiol 2014; 5:438. [PMID: 25505417 PMCID: PMC4241833 DOI: 10.3389/fphys.2014.00438] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 10/27/2014] [Indexed: 11/13/2022] Open
Abstract
Oscillatory breathing (OB) patterns are observed in pre-term infants, patients with cardio-renal impairment, and in otherwise healthy humans exposed to high altitude. Enhanced carotid body (CB) chemoreflex sensitivity is common to all of these populations and is thought to contribute to these abnormal patterns by destabilizing the respiratory control system. OB patterns in chronic heart failure (CHF) patients are associated with greater levels of tonic and chemoreflex-evoked sympathetic nerve activity (SNA), which is associated with greater morbidity and poor prognosis. Enhanced chemoreflex drive may contribute to tonic elevations in SNA by strengthening the relationship between respiratory and sympathetic neural outflow. Elimination of CB afferents in experimental models of CHF has been shown to reduce OB, respiratory-sympathetic coupling, and renal SNA, and to improve autonomic balance in the heart. The CB chemoreceptors may play an important role in progression of CHF by contributing to respiratory instability and OB, which in turn further exacerbates tonic and chemoreflex-evoked increases in SNA to the heart and kidney.
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Affiliation(s)
- Noah J Marcus
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center Omaha, NE, USA
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Center of Biomedical Research, Universidad Autónoma de Chile Santiago, Chile
| | - Harold D Schultz
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center Omaha, NE, USA
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Khan A, Morgenthaler TI, Ramar K. Sleep disordered breathing in isolated unilateral and bilateral diaphragmatic dysfunction. J Clin Sleep Med 2014; 10:509-15. [PMID: 24910552 PMCID: PMC4046357 DOI: 10.5664/jcsm.3698] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION The effect of isolated unilateral or bilateral diaphragmatic dysfunction (DD), in the absence of a generalized neuromuscular disorder, on sleep disordered breathing (SDB) is not well understood. The type of positive airway pressure (PAP) device needed to treat SDB in patients with isolated DD is also not well established. METHODS We retrospectively analyzed data on patients with isolated unilateral or bilateral DD who were referred for polysomnography (PSG) for clinical symptoms or abnormal oximetry between 1994 and 2006. RESULTS We found 66 patients who met criteria, of whom 74.2% were males with an average age of 58.8 ± 10.9 years. 56 had isolated unilateral DD, and 10 had isolated bilateral DD. All had significant SDB with an apnea-hypopnea index (AHI) of 26.6 ± 28.4. There were no significant differences in PSG measures, arterial blood gas analysis, pulmonary function tests, or echocardiographic data, except for lower maximal inspiratory pressure in patients with bilateral DD compared to unilateral DD (40.2% ± 17.8% vs. 57.7% ± 20.5%, p = 0.02). Control of SDB with continuous PAP (CPAP) was possible in only 37.9% of patients with the rest requiring bilevel PAP (BPAP). Patients with isolated bilateral DD and SDB were 6.8 times more likely to fail CPAP than those with unilateral DD (p = 0.03). CONCLUSIONS Most patients with isolated DD failed CPAP and required BPAP. Patients with bilateral DD were more likely to require BPAP than those with unilateral DD. Patients with isolated DD should be considered for in-lab titration to determine adequacy of therapy.
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Affiliation(s)
- Akram Khan
- Division of Pulmonary and Critical Care Medicine, Oregon Health Science Center, Portland, OR
| | - Timothy I. Morgenthaler
- Center for Sleep Medicine, Division of Pulmonary and Critical Care, Mayo Clinic, Rochester, MN
| | - Kannan Ramar
- Center for Sleep Medicine, Division of Pulmonary and Critical Care, Mayo Clinic, Rochester, MN
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D'Elia E, Vanoli E, La Rovere MT, Fanfulla F, Maggioni A, Casali V, Damiano S, Specchia G, Mortara A. Adaptive servo ventilation reduces central sleep apnea in chronic heart failure patients: beneficial effects on autonomic modulation of heart rate. J Cardiovasc Med (Hagerstown) 2013; 14:296-300. [PMID: 22498996 DOI: 10.2459/jcm.0b013e32835364b2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIM Adaptive servo ventilation (ASV) is a method of ventilator support aimed to treat central sleep apnea (CSA). We investigated the effects of an acute use of ASV in chronic heart failure (CHF) patients with CSA and the potential influence on sympathetic nerve activity. METHODS Patients were studied with ambulatory cardio-respiratory 24 Holter (Somtè) recording of air flow, ECG and oxygen saturation. Comparison before and after ASV treatment was made for apnea index (AI), apnea-hypopnea index (AHI), pulse oxygen saturation, desaturation related to apnea, heart rate (HR) and heart rate variability (HRV). RESULTS Seventeen patients were enrolled. At baseline, apnea index and apnea-hypopnea index were, respectively, 16.92 ± 7.8 and 41.37 ± 17.5. During ASV, they significantly decreased to 0.06 ± 0.0 (P < 0.001) and 2.84 ± 1.1 (P < 0.001). The mean and minimal oxygen saturation (%) increased from 94 ± 1 and 86.5 ± 4 to 95 ± 2 (P = 0.04) and 91 ± 2 (P = 0.008). Mean HR decreased from 68 ± 10 to 62 ± 7 beats/min (P < 0.003). In 11 out of 17 patients, HRV was calculated, documenting a significant improvement of the standard deviation of the average of NN - normal sinus to normal sinus (SDANN), standard deviation of NN intervals (SDNN) and SDNN index (respectively, 71.5 ± 31.1 vs. 80.4 ± 36.1, P = 0.008; 99.7 ± 31.3 vs. 112.7 ± 37.5, P = 0.003; 57.8 ± 20.7 vs. 69.3 ± 30.8, P = 0.03). CONCLUSION The acute use of ASV is effective on CSA by increasing oxygen saturation and reducing HR. Moreover, the significant improvement of HRV highlights ASV's benefit in moderating the sympathetic adrenergic tone.
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Affiliation(s)
- Emilia D'Elia
- Cardiology Department, Policlinico di Monza, Monza, Italy.
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Abstract
Complex sleep apnea syndrome (CompSAS) describes the coexistence or appearance and persistence of central apneas or hypopneas in patients with obstructive sleep apnea upon successful restoration of airway patency. We review data on treatment of CompSAS with CPAP, bilevel positive airway pressure, and adaptive servoventilation and discuss evidence for the addition of medications (analgesics, hypnotics, acetazolamide) and gases (oxygen, CO2) to positive airway pressure therapy. Future research should focus on defining outcomes in patients with CompSAS and allow for more accurate tailoring of therapy to the pathophysiology present in the individual patient.
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Affiliation(s)
- Tomasz J Kuźniar
- Department of Internal Medicine, 4th Clinical Military Hospital, Wrocław, Poland
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Jurysta F, Kempenaers C, Lanquart JP, Noseda A, van de Borne P, Linkowski P. Long-term CPAP treatment partially improves the link between cardiac vagal influence and delta sleep. BMC Pulm Med 2013; 13:29. [PMID: 23628083 PMCID: PMC3685543 DOI: 10.1186/1471-2466-13-29] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 04/18/2013] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND Continuous positive airway pressure (CPAP) treatment improves the risk of cardiovascular events in patients suffering from severe sleep apnea-hypopnea syndrome (SAHS) but its effect on the link between delta power band that is related to deep sleep and the relative cardiac vagal component of heart rate variability, HF(nu) of HRV, is unknown. Therefore, we tested the hypothesis that CPAP restores the link between cardiac autonomic activity and delta sleep across the night. METHODS Eight patients suffering from severe SAHS before and after 4 ± 3 years of nasal CPAP treatment were matched with fourteen healthy controls. Sleep EEG and ECG were analysed to obtain spectral sleep and HRV components. Coherence analysis was applied between HF(nu) and delta power bands across the first three sleep cycles. RESULTS Sleep characteristics and spectral HRV components were similar between untreated patients, treated patients and controls, with the exception of decreased Rapid Eye Movement duration in untreated patients. Coherence and gain values between HF(nu) and delta EEG variability were decreased in untreated patients while gain values normalized in treated patients. In patients before and during long-term CPAP treatment, phase shift and delay between modifications in HF(nu) and delta EEG variability did not differ from controls but were not different from zero. In healthy men, changes in cardiac vagal activity appeared 9 ± 7 minutes before modifications in delta sleep. CONCLUSIONS Long-term nasal CPAP restored, in severe SAHS, the information between cardiovascular and sleep brainstem structures by increasing gain, but did not improve its tightness or time shift.
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Affiliation(s)
- Fabrice Jurysta
- Sleep Laboratory and Laboratory of Psychiatric Research, Department of Psychiatry, Erasme Academic Hospital - ULB, Brussels, Belgium
| | - Chantal Kempenaers
- Sleep Laboratory and Laboratory of Psychiatric Research, Department of Psychiatry, Erasme Academic Hospital - ULB, Brussels, Belgium
| | - Jean-Pol Lanquart
- Sleep Laboratory and Laboratory of Psychiatric Research, Department of Psychiatry, Erasme Academic Hospital - ULB, Brussels, Belgium
| | - André Noseda
- Chest Department, Erasme Academic Hospital-ULB, Brussels, Belgium
| | - Philippe van de Borne
- Department of Cardiology and Hypertension Clinic, Erasme Academic Hospital - ULB, Brussels, Belgium
| | - Paul Linkowski
- Sleep Laboratory and Laboratory of Psychiatric Research, Department of Psychiatry, Erasme Academic Hospital - ULB, Brussels, Belgium
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Kuźniar TJ, Kasibowska-Kuźniar K, Ray DW, Freedom T. Clinical heterogeneity of patients with complex sleep apnea syndrome. Sleep Breath 2013; 17:1209-14. [PMID: 23436008 PMCID: PMC3898341 DOI: 10.1007/s11325-013-0825-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 01/31/2013] [Accepted: 02/11/2013] [Indexed: 12/31/2022]
Abstract
Background The definition of complex sleep apnea (CompSAS) encompasses patients with obstructive sleep apnea (OSA) who develop central apnea activity upon restitution of airway patency. Presence of arterial hypertension (HTN), coronary artery disease (CAD) and heart failure (HF) have been proposed as risk factors for CompSAS among OSA patients. Using our database of patients with CompSAS, we examined the prevalence of these risk factors and defined other clinical characteristics of patients with CompSAS. Methods Through retrospective search of the database, we examined the medical and clinical characteristics of consecutive patients diagnosed with CompSAS between 11/1/2006 and 6/30/2011 at NorthShore University HealthSystem. Results One hundred and fifty patients with CompSAS were identified. Among patients included in the study, 97 (64.7 %) had at least one risk factor for CompSAS, while 53 (35.3 %) did not have any of them. Prevalence of low left ventricular ejection fraction and hypocapnia were low. Therapeutic interventions consisted of several positive airway pressure therapies, mainly adaptive servo ventilation. A hundred and ten patients (73.3 %) complied with recommended therapy and improved clinically. Conclusions Although most patients with CompSAS have cardiac comorbidities, about one third of patients do not have any risk factors of CompSAS prior to sleep testing. Further research on factors involved in development of CompSAS will allow for better tailoring of therapy to pathophysiology involved in an individual case.
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Affiliation(s)
- Tomasz J Kuźniar
- Division of Pulmonary and Critical Care Medicine, NorthShore University HealthSystem, 2650 Ridge Avenue, Evanston, IL, USA,
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Goldstein C, Kuzniar TJ. The emergence of central sleep apnea after surgical relief of nasal obstruction in obstructive sleep apnea. J Clin Sleep Med 2012; 8:321-2. [PMID: 22701391 DOI: 10.5664/jcsm.1926] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
By the current definition, complex sleep apnea (CompSA) refers to the emergence of central sleep apnea (CSA) during the treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP). However, new-onset CSA has been described with use of other treatments for OSA, including tracheostomy, maxillofacial surgery, and mandibular advancement device. We present a patient with CSA beginning after endoscopic sinus and nasal surgery for nasal obstruction in the setting of mild OSA. This case highlights the importance of non-PAP mechanisms in the pathogenesis of CompSA.
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Affiliation(s)
- Cathy Goldstein
- Sleep Disorders Center, NorthShore University Health System, Evanston, IL, USA.
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Kline DD. Chronic intermittent hypoxia affects integration of sensory input by neurons in the nucleus tractus solitarii. Respir Physiol Neurobiol 2010; 174:29-36. [PMID: 20416405 DOI: 10.1016/j.resp.2010.04.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 04/13/2010] [Accepted: 04/13/2010] [Indexed: 01/19/2023]
Abstract
The autonomic nervous and respiratory systems, as well as their coupling, adapt over a wide range of conditions. Chronic intermittent hypoxia (CIH) is a model for recurrent apneas and induces alterations in breathing and increases in sympathetic nerve activity which may ultimately result in hypertension if left untreated. These alterations are believed to be due to increases in the carotid body chemoreflex pathway. Here we present evidence that the nucleus tractus solitarii (nTS), the central brainstem termination site of chemoreceptor afferents, expresses a form of synaptic plasticity that increases overall nTS activity following intermittent hypoxia. Following CIH, an increase in presynaptic spontaneous neurotransmitter release occurs under baseline conditions. Furthermore, during and following afferent stimulation there is an augmentation of spontaneous transmitter release that occurs out of synchrony with sensory stimulation. On the other hand, afferent evoked synchronous transmitter release is attenuated. Overall, this shift from synchronous to asynchronous transmitter release enhances nTS cellular discharge. The role of the neurotransmitter dopamine in CIH-induced plasticity is also discussed. Dopamine attenuates synaptic transmission in nTS cells by blockade of N-type calcium channels, and this mechanism occurs tonically following normoxia and CIH. This dopaminergic pathway, however, is not altered in CIH. Taken together, alterations in nTS synaptic activity may play a role in the changes of chemoreflex function and cardiorespiratory activity in the CIH apnea model.
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Affiliation(s)
- David D Kline
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA.
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Loewen A, Ostrowski M, Laprairie J, Atkar R, Gnitecki J, Hanly P, Younes M. Determinants of ventilatory instability in obstructive sleep apnea: inherent or acquired? Sleep 2009; 32:1355-65. [PMID: 19848364 DOI: 10.1093/sleep/32.10.1355] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
STUDY OBJECTIVES Certain respiratory control characteristics determine whether patients with collapsible upper airway develop stable or unstable breathing during sleep, thereby influencing the severity of obstructive apnea (OSA). These include arousal threshold (T(A)), response to transient hypoxia and hypercapnia (Dynamic Response) and the increase in respiratory drive required for arousal-free airway opening (T(ER)). We wished to determine whether these characteristics are inherent or are acquired during untreated OSA. DESIGN T(A), Dynamic Response, and T(ER) were measured in patients with severe OSA before and after treatment with continuous positive airway pressure (CPAP). Changes observed after treatment were deemed to have been acquired during untreated OSA. SETTING University-based sleep laboratory. PATIENTS 15 patients with severe OSA. INTERVENTIONS (1) 30-sec alterations in inspired gases during sleep on CPAP. (2) Brief dial-downs of CPAP (dial-downs) both during air breathing and when ventilation was increased to different levels. MEASUREMENTS AND RESULTS T(A): the increase in ventilation associated with a 50% probability of arousal (T(A)50). Dynamic Response: the increase in ventilation on the 5th breath following breathing 3% CO2 in 11% to 15% O2. T(ER): the increase in ventilation prior to dial-downs that was associated with an arousal-free airway opening during dial-down. CPAP therapy (10.5 +/- 4.3 months) resulted in marked reduction in Dynamic Response (131% +/- 95% to 52% +/- 34% baseline ventilation, P < 0.005), a decrease in T(A)50 (134% +/- 78% to 86% +/- 47% baseline ventilation, P < 0.05), and no change in T(ER). CONCLUSIONS T(ER) may be an inherent characteristic. Untreated OSA results in an increase in dynamic response to asphyxia and an increase in arousal threshold.
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Affiliation(s)
- Andrea Loewen
- Sleep Center, Foothills Medical Centre, University of Calgary, Calgary, Canada
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Pialoux V, Hanly PJ, Foster GE, Brugniaux JV, Beaudin AE, Hartmann SE, Pun M, Duggan CT, Poulin MJ. Effects of Exposure to Intermittent Hypoxia on Oxidative Stress and Acute Hypoxic Ventilatory Response in Humans. Am J Respir Crit Care Med 2009; 180:1002-9. [DOI: 10.1164/rccm.200905-0671oc] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Evidence-Based Patient Safety Advisory: Patient Assessment and Prevention of Pulmonary Side Effects in Surgery. Part 1—Obstructive Sleep Apnea and Obstructive Lung Disease. Plast Reconstr Surg 2009; 124:45S-56S. [DOI: 10.1097/prs.0b013e3181b5338d] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Reichmuth KJ, Dopp JM, Barczi SR, Skatrud JB, Wojdyla P, Hayes D, Morgan BJ. Impaired vascular regulation in patients with obstructive sleep apnea: effects of continuous positive airway pressure treatment. Am J Respir Crit Care Med 2009; 180:1143-50. [PMID: 19745203 DOI: 10.1164/rccm.200903-0393oc] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
RATIONALE Impaired endothelium-dependent vasodilation has been documented in patients with sleep apnea. This impairment may result in blood flow dysregulation during apnea-induced fluctuations in arterial blood gases. OBJECTIVES To test the hypothesis that hypoxic and hypercapnic vasodilation in the forearm and cerebral circulation are impaired in patients with sleep apnea. METHODS We exposed 20 patients with moderate to severe sleep apnea and 20 control subjects, to isocapnic hypoxia and hyperoxic hypercapnia. A subset of 14 patients was restudied after treatment with continuous positive airway pressure. MEASUREMENTS AND MAIN RESULTS Cerebral flow velocity (transcranial Doppler), forearm blood flow (venous occlusion plethysmography), arterial pressure (automated sphygmomanometry), oxygen saturation (pulse oximetry), ventilation (pneumotachograph), and end-tidal oxygen and carbon dioxide tensions (expired gas analysis) were measured during three levels of hypoxia and two levels of hypercapnia. Cerebral vasodilator responses to hypoxia (-0.65 +/- 0.44 vs. -1.02 +/- 0.72 [mean +/- SD] units/% saturation; P = 0.03) and hypercapnia (2.01 +/- 0.88 vs. 2.57 +/- 0.89 units/mm Hg; P = 0.03) were smaller in patients versus control subjects. Hypoxic vasodilation in the forearm was also attenuated (-0.05 +/- 0.09 vs. -0.10 +/- 0.09 unit/% saturation; P = 0.04). Hypercapnia did not elicit forearm vasodilation in either group. Twelve weeks of continuous positive airway pressure treatment enhanced hypoxic vasodilation in the cerebral circulation (-0.83 +/- 0.32 vs. -0.46 +/- 0.29 units/% saturation; P = 0.01) and forearm (-0.19 +/- 0.15 vs. -0.02 +/- 0.08 units/% saturation; P = 0.003), and hypercapnic vasodilation in the brain showed a trend toward improvement (2.24 +/- 0.78 vs. 1.76 +/- 0.64 units/mm Hg; P = 0.06). CONCLUSIONS Vasodilator responses to chemical stimuli in the cerebral circulation and the forearm are impaired in many patients with obstructive sleep apnea. Some of these impairments can be improved with continuous positive airway pressure.
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Affiliation(s)
- Kevin J Reichmuth
- Departments of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison and Middleton Veterans Administration Hospital, Madison, WI, USA
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Marrone O. Complex sleep apnea and obesity hypoventilation syndrome. Opposite ends of the spectrum of obstructive sleep apnea? Med Hypotheses 2009; 73:488-92. [PMID: 19596168 DOI: 10.1016/j.mehy.2009.03.060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2009] [Revised: 03/28/2009] [Accepted: 03/31/2009] [Indexed: 12/28/2022]
Abstract
In most cases, the application of continuous positive airway pressure (CPAP) during sleep in patients affected by obstructive sleep apnea (OSA) eliminates upper airway obstruction and makes breathing stable and regular. However, some OSA patients develop periodic breathing and central apneas during CPAP administration, a finding that has been labelled as "complex sleep apnea" (complex SA). Such breathing disorder may occur only acutely after CPAP treatment initiation or sometimes persist with chronic CPAP treatment. We hypothesize that complex SA may be the consequence of mechanisms analogous to those leading to obesity hypoventilation syndrome (OHS), but operating in an opposite direction. Periodic breathing is one of the factors predisposing to OSA and is an essential factor for the recurrence of central apneas in normo or hypocapnic patients. A high ventilatory responsiveness to chemical stimuli enhances breathing periodicity. In subjects with periodic central apneas chemoresponsiveness is high, while in subjects with OSA it spans throughout a wide range, and is correlated to diurnal blood gas levels. In fact, sleep respiratory disorders may be responsible for either an augmentation in ventilatory responses to chemical stimuli consequent to chronic exposure to intermittent hypoxia, or for a decrease in ventilatory responses when prolonged exposure to hypercapnia is experienced. Among OSA subjects, those with OHS show very depressed hypercapnic responses. After chronic OSA treatment, ventilatory responses to chemical stimuli may either decrease, in previously hyperresponsive subjects, or increase, in previously hyporesponsive subjects. Most patients with OHS decrease daytime PCO(2) levels and increase their ventilatory responses after chronic CPAP treatment. Complex SA could appear in those OSA subjects in whom chronic exposure to nocturnal respiratory disorders leads to the highest responsiveness to chemical stimuli, and could disappear after blunting of ventilatory responses following chronic CPAP treatment. Complex SA may be one extreme of evolutionary spectrum of OSA, the opposite end being represented by OHS.
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Affiliation(s)
- Oreste Marrone
- Consiglio Nazionale delle Ricerche, Istituto di Biomedicina e Immunologia Molecolare, Via Ugo La Malfa, 153, 90146 Palermo, Italy.
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Combined increased chemosensitivity to hypoxia and hypercapnia as a prognosticator in heart failure. J Am Coll Cardiol 2009; 53:1975-80. [PMID: 19460611 DOI: 10.1016/j.jacc.2009.02.030] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 02/09/2009] [Accepted: 02/16/2009] [Indexed: 11/23/2022]
Abstract
OBJECTIVES The aim of the present study was to investigate the prognostic significance of chemosensitivity to hypercapnia in chronic heart failure (HF). BACKGROUND Increased chemosensitivity to hypoxia and hypercapnia has been observed in HF. The potential value of enhanced chemosensitivity to hypercapnia to risk prediction in systolic HF has not been specifically evaluated. METHODS One hundred ten consecutive systolic HF patients (age 62 +/- 15 years, left ventricular ejection fraction [LVEF] 31 +/- 7%) underwent assessment of chemosensitivity to hypoxia and hypercapnia (rebreathing technique) and were followed up for a median period of 29 months (range 1 to 54 months). The end point was a composite of cardiac death and aborted cardiac death (ventricular tachyarrhythmia treated by cardioverter-defibrillator). RESULTS At baseline, 31 patients (28%) had enhanced chemosensitivity to both hypoxia and hypercapnia. Although they had the same LVEF as the 43 patients (39%) with normal chemosensitivity, they were more symptomatic (New York Heart Association functional class), had higher plasma brain natriuretic peptide and norepinephrine, steeper regression slope relating minute ventilation to carbon dioxide output (V(E)/V(CO2) slope), more Cheyne-Stokes respiration, and more ventricular arrhythmias (all p < 0.05). Four-year survival was only 49%, in marked contrast to 100% for patients with normal chemosensitivity (p < 0.001). On multivariate analysis, combined elevation in chemosensitivity was the strongest independent prognostic marker, even when adjusted for univariate predictors (V(E)/V(CO2) slope, Cheyne-Stokes respiration, LVEF, and brain natriuretic peptide, p < 0.05). CONCLUSIONS Increased chemosensitivity to both hypoxia and hypercapnia, eliciting neurohormonal derangement, ventilation instability, and ventricular arrhythmias, is a very serious adverse prognostic marker in HF.
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