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Roberts EG, Raphelson JR, Orr JE, LaBuzetta JN, Malhotra A. The Pathogenesis of Central and Complex Sleep Apnea. Curr Neurol Neurosci Rep 2022; 22:405-412. [PMID: 35588042 PMCID: PMC9239939 DOI: 10.1007/s11910-022-01199-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2022] [Indexed: 11/09/2022]
Abstract
PURPOSE The purpose of this article is to review the recent literature on central apnea. Sleep disordered breathing (SDB) is characterized by apneas (cessation in breathing), and hypopneas (reductions in breathing), that occur during sleep. Central sleep apnea (CSA) is sleep disordered breathing in which there is an absence or diminution of respiratory effort during breathing disturbances while asleep. In obstructive sleep apnea (OSA), on the other hand, there is an absence of flow despite ongoing ventilatory effort. RECENT FINDINGS Central sleep apnea is a heterogeneous disease with multiple clinical manifestations. OSA is by far the more common condition; however, CSA is highly prevalent among certain patient groups. Complex sleep apnea (CompSA) is defined as the occurrence/emergence of CSA upon treatment of OSA. Similarly, there is considerable overlap between CSA and OSA in pathogenesis as well as impacts. Thus, understanding sleep disordered breathing is important for many practicing clinicians.
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Affiliation(s)
- Erin Grattan Roberts
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, San Diego, CA, 92037, USA.
| | - Janna R Raphelson
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, San Diego, CA, 92037, USA
| | - Jeremy E Orr
- Division of Critical Care, Sleep Medicine and Physiology, Department of Medicine, University of California San Diego, San Diego, CA, USA
| | - Jamie Nicole LaBuzetta
- Division of Neurocritical Care, Department of Neurosciences, University of California San Diego, San Diego, CA, USA
| | - Atul Malhotra
- Division of Critical Care, Sleep Medicine and Physiology, Department of Medicine, University of California San Diego, San Diego, CA, USA
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Ventrikuläre Arrhythmien bei obstruktiver und zentraler Schlafapnoe. SOMNOLOGIE 2021. [DOI: 10.1007/s11818-021-00319-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Zusammenfassung
Hintergrund
Ventrikuläre Arrhythmien treten mit einer hohen Prävalenz auf und sind mit einer hohen Morbidität und Mortalität assoziiert. Sowohl die obstruktive (OSA) als auch die zentrale (ZSA) Schlafapnoe können auf Grund ihrer Pathophysiologie zu vermehrten ventrikulären Arrhythmien beitragen.
Ziel
Dieser Artikel soll die komplexen Zusammenhänge und Erkenntnisse jüngster Forschungen bezüglich schlafbezogenen Atmungsstörungen (SBAS) und ventrikulärer Arrhythmien und deren Therapiemöglichkeiten beleuchten.
Material und Methoden
Es erfolgte eine Literaturrecherche basierend auf prospektiven, retrospektiven, klinischen und experimentellen Studien sowie Reviews, Metaanalysen und aktuellen Leitlinien, die seit 2014 in der Medline-Datenbank gelistet wurden.
Ergebnisse
Es besteht ein bidirektionaler Zusammenhang zwischen der SBAS und ventrikulären Arrhythmien. Intermittierende Hypoxie, oxidativer Stress, wiederkehrende Arousals, intrathorakale Druckschwankungen und kardiales Remodeling tragen im Rahmen der SBAS zu einer erhöhten ventrikulären Arrhythmieneigung bei. Der Schweregrad der OSA, gemessen mittels Apnoe-Hypopnoe-Index, ist mit der Prävalenz ventrikulärer Arrhythmien assoziiert. Ähnliche Ergebnisse liegen für Patienten mit ZSA und Herzinsuffizienz vor. Studien zu ventrikulären Arrhythmien bei ZSA-Patienten ohne Herzinsuffizienz fehlen. Eine Positivdrucktherapie (PAP) bei OSA- oder ZSA-Patienten führte in verschiedenen Studien zu einer reduzierten Anzahl an ventrikulären Arrhythmien. Dieser Zusammenhang konnte jedoch nicht in allen Studien bestätigt werden. Ventrikuläre Arrhythmien treten bei der OSA gehäuft nachts auf, bei der ZSA gleichmäßig über den Tag verteilt.
Diskussion
Bisherige Studien weisen einen Zusammenhang zwischen der OSA bzw. der ZSA und ventrikulären Arrhythmien trotz unterschiedlicher Pathophysiologie nach. Hinsichtlich des Effektes der PAP auf ventrikuläre Arrhythmien bei Patienten mit OSA und ZSA sind weitere Studien erforderlich.
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Schreib AW, Arzt M, Heid IM, Jung B, Böger CA, Stadler S. Periodic breathing is associated with blood pressure above the recommended target in patients with type 2 diabetes. Sleep Med X 2020; 2:100013. [PMID: 33870170 PMCID: PMC8041113 DOI: 10.1016/j.sleepx.2020.100013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/17/2020] [Accepted: 02/25/2020] [Indexed: 12/05/2022] Open
Abstract
Background Due to its prognostic importance for patients with type 2 diabetes (DM2), current guidelines recommend a systolic <130 mm Hg and diastolic <80 mm Hg blood pressure target. Periodic breathing, a form of sleep-disordered breathing, acutely causes repetitive hypoxia, sympathetic nervous system activation as well as oscillations of heart rate and blood pressure. However, limited data on the association of periodic breathing and control of blood pressure (BP) in patients with DM2 are available. Thus, the aim of the present study was to assess whether there is an association between periodic breathing and increased BP above the recommended target in DM2. Methods Cross-sectional data of 679 patients with DM2 from the DIACORE-SDB sub-study were analysed for association of periodic breathing with BP. Sleep-disordered breathing was assessed with a 2-channel ambulatory monitoring device including validated automatic pattern recognition for periodic breathing. BP values were determined in a standardized manner with three repeated measurements at rest. Results Of the 679 analysed individuals (61% male, age 66 ± 9 years, Body Mass Index [BMI] 31.0 ± 5.4 kg/m2), 11% had periodic breathing. Patients with periodic breathing had significantly higher systolic BP values (144 ± 19 mm Hg vs. 137 ± 18 mm Hg, p = 0.003). Multivariable regression analysis revealed that periodic breathing was associated with higher systolic BP (B [95% confidence interval, CI] = 4.4 [0.1; 8.7], p = 0.043) and not meeting the recommended BP target for patients with diabetes (<130/80 mmHg) (odds ratio, OR [95%CI] = 2.1 [1.1; 4.0], p = 0.026) independent of sex, age, high density lipoproteins, renal function, coronary heart disease and antihypertensive treatment. Conclusion Periodic breathing is associated with higher systolic BP in patients with DM2. periodic and sleep disordered breathing are associated with blood pressure values above blood pressure target for diabetes. elevated blood pressure is highly prevalent in diabetes and periodic breathing despite extensive use of antihypertensives. periodic breathing is associated with higher systolic blood pressure independently from other risk factors.
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Verbraecken J. The search for optimal blood pressure control in type 2 diabetes mellitus: have we found the holy grail? Sleep Med X 2020; 2:100015. [PMID: 33871472 PMCID: PMC8041107 DOI: 10.1016/j.sleepx.2020.100015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Johan Verbraecken
- Department of Pulmonary Medicine and Multidisciplinary Sleep Disorders Centre, Antwerp University Hospital and University of Antwerp, Wilrijkstraat 10, 2650 Edegem, Antwerp, Belgium
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Pinna GD, La Rovere MT, Robbi E, Tavazzi L, Maestri R. CARDIAC chronotropic effects of sleep-disordered breathing in patients with heart failure. J Sleep Res 2020; 30:e13160. [PMID: 32791565 DOI: 10.1111/jsr.13160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/09/2020] [Accepted: 07/15/2020] [Indexed: 11/30/2022]
Abstract
It is still not known whether the oscillation in heart rate (HR) induced by sleep-disordered breathing (SDB) in patients with heart failure entails significant chronotropic effects. We hypothesised that since cyclical changes in ventilation and arterial blood gases during SDB affect HR through multiple and complexly interacting mechanisms characterised by large inter-subject variability, chronotropic effects may change from patient to patient. A total of 42 patients with moderate-to-severe chronic heart failure with systolic dysfunction underwent an in-hospital sleep study. Chronotropic effects of SDB were quantified by comparing the distribution of instantaneous HR during SDB with that during periods without SDB (noSDB) within the same night in each patient. Based on distribution changes from noSDB to SDB, 12, nine, 11, and 10 patients showed a significant tachycardic, bradycardic, tachycardic and bradycardic, and neither significant tachycardic nor significant bradycardic effect, respectively. Tachycardic and bradycardic effects were primarily due to an increase in the rate rather than in the magnitude of cyclical HR elevations and reductions, and were more prevalent and severe in patients with dominant obstructive and central events, respectively. The apnea-hypopnea index did not differ between groups. Conversely, the time spent with an oxygen saturation of <90% was greater in the tachycardic and tachycardic-bradycardic groups compared to the bradycardic group. These findings indicate that HR distribution changes induced by SDB can vary from patient to patient revealing four distinct and well-characterised chronotropic effects. These effects are related to the degree of hypoxic burden brought about by SDB and are affected by the type of sleep apnea (central/obstructive).
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Affiliation(s)
- Gian Domenico Pinna
- Department of Biomedical Engineering, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy
| | - Maria Teresa La Rovere
- Department of Cardiology, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy
| | - Elena Robbi
- Department of Cardiology, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy.,Sleep Laboratory, Department of Pneumology, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy
| | - Luigi Tavazzi
- Maria Cecilia Hospital, GVM Care and Research, Cotignola, Italy
| | - Roberto Maestri
- Department of Biomedical Engineering, Istituti Clinici Scientifici Maugeri, IRCCS Montescano, Montescano, Italy
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Kahn D, Baele P, Pasquet A, Liistro G. Cheyne-Stokes respiration and cardiovascular oscillations ending abruptly when deploying transfemoral aortic valve. J Appl Physiol (1985) 2020; 128:345-349. [PMID: 31873067 DOI: 10.1152/japplphysiol.00193.2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A 86-yr-old man was referred for transfemoral aortic valve implantation. Transthoracic echocardiography revealed a severe stenosis (mean gradient: 58 mmHg, aortic valve area: 0.4 cm2), and after multidisciplinary discussion, the risk of surgery was judged too high (logistic Euroscore: 51%), and the patient was proposed for a transfemoral aortic valve implantation (TAVI). On arrival in the operating room, the patient, fully conscious, was noted to have Cheyne-Stokes breathing (CSB), which persisted after 40% oxygen administration. TAVI procedure was successful, and the CSB pattern was interrupted within 8 s. To the best of our knowledge, this report is the first to show an acute disappearance of CSB, occurring only seconds after TAVI and restoration of a normal hemodynamic situation. To explain such rapid changes in breathing pattern, we hypothesize a role played by the acute release of pulmonary hypertension and pulmonary volume overload.NEW & NOTEWORTHY Acute disappearance of Cheyne-Stokes breathing after transfemoral aortic valve implantation suggests a reflex pathway originating from the fall in pulmonary vessels congestion.
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Affiliation(s)
- David Kahn
- Department of Anaesthesiology, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Philippe Baele
- Department of Anaesthesiology, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Agnès Pasquet
- Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Giuseppe Liistro
- Pôle de Pneumologie, ORL et Dermatologie, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.,Service de Pneumologie, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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7
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Arterial oxygen saturation during Cheyne-Stokes respiration in heart failure patients: does measurement site matter? Sleep Med 2019; 55:6-13. [DOI: 10.1016/j.sleep.2018.10.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 08/30/2018] [Accepted: 10/15/2018] [Indexed: 11/17/2022]
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8
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Pinna GD, Robbi E, Terzaghi M, Corbellini D, La Rovere MT, Maestri R. Temporal relationship between arousals and Cheyne-Stokes respiration with central sleep apnea in heart failure patients. Clin Neurophysiol 2018; 129:1955-1963. [DOI: 10.1016/j.clinph.2018.05.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/11/2018] [Accepted: 05/31/2018] [Indexed: 10/28/2022]
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9
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Aziz EF, Selby A, Argulian E, Aziz J, Herzog E. Pathway for the Management of Sleep Apnea in the Cardiac Patient. Crit Pathw Cardiol 2017; 16:81-88. [PMID: 28742642 DOI: 10.1097/hpc.0000000000000118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Sleep-disordered breathing is a highly prevalent medical condition, which if undiagnosed leads to increased morbidity and mortality, particularly related to increased incidence of cardiovascular events. It is therefore imperative that we identify patient population at high risk for sleep apnea and refer them to the appropriate therapy as early as possible. Up-to-date there is no management guideline specifically geared towards cardiac patients. Thus, we propose a (SAP) Sleep Apnea Pathway to correctly identify and triage these patients to the appropriate therapy.
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Affiliation(s)
- Emad F Aziz
- From Mount Sinai St. Luke's and Mount Sinai West Hospitals, Icahn School of Medicine at Mount Sinai, New York, NY
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10
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Abstract
Subspecialty pediatric practice provides comprehensive medical care for a range of ages, from premature infants to children, and often includes adults with complex medical and surgical issues that warrant multidisciplinary care. Normal physiologic variations involving different body systems occur during sleep and these vary with age, stage of sleep, and underlying health conditions. This article is a concise review of the cardiovascular (CV) physiology and pathophysiology in children, sleep-disordered breathing (SDB) contributing to CV morbidity, congenital and acquired CV pathology resulting in SDB, and the relationship between SDB and CV morbidity in different clinical syndromes and systemic diseases in the expanded pediatric population.
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Affiliation(s)
- Grace R Paul
- Division of Pulmonary and Sleep Medicine, Nationwide Children's Hospital, The Ohio State University, 700 Children's Drive, Columbus, OH 43205, USA.
| | - Swaroop Pinto
- Division of Pulmonary and Sleep Medicine, Nationwide Children's Hospital, The Ohio State University, 700 Children's Drive, Columbus, OH 43205, USA
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11
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Kahwash R, Khayat RN. A Practical Approach to the Identification and Management of Sleep-Disordered Breathing in Heart Failure Patients. Sleep Med Clin 2017; 12:205-219. [PMID: 28477775 DOI: 10.1016/j.jsmc.2017.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sleep-disordered breathing (SDB) is a major health problem affecting much of the general population. Although SDB is responsible for rapid progression of heart failure (HF) and the worsening morbidity and mortality, advanced HF state is associated with accelerated development of SDB. In the face of recent developments in SDB treatment and availability of effective therapeutic options known to improve quality of life, exercise tolerance, and heart function, most HF patients with SDB are left unrecognized and untreated. This article provides an overview of SDB in HF with focus on practical approaches intended to facilitate screening and treatment.
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Affiliation(s)
- Rami Kahwash
- Section of Heart Failure and Transplant, Division of Cardiovascular Medicine, Davis Heart & Lung Research Institute, The Ohio State University, 473 West 12th Avenue, Columbus, OH 43210, USA.
| | - Rami N Khayat
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Davis Heart & Lung Research Institute, The Ohio State University, 473 West 12th Avenue, Columbus, OH 43210, USA
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Abstract
Congestive heart failure (CHF) is among the most common causes of admission to hospitals in the United States, especially in those over age 65. Few data exist regarding the prevalence CHF of Cheyne-Stokes respiration (CSR) owing to congestive heart failure in the intensive care unit (ICU). Nevertheless, CSR is expected to be highly prevalent among those with CHF. Treatment should focus on the underlying mechanisms by which CHF increases loop gain and promotes unstable breathing. Few data are available to determine prevalence of CSR in the ICU, or how CSR might affect clinical management and weaning from mechanical ventilation.
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Affiliation(s)
- Scott A Sands
- Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA; Department of Allergy, Immunology and Respiratory Medicine and Central Clinical School, Alfred Hospital and Monash University, 55 Commercial Rd, Melbourne, VIC 3004, Australia
| | - Robert L Owens
- Division of Pulmonary and Critical Care Medicine, University of California San Diego, 9300 Campus Point Drive, #7381, La Jolla, CA 92037, USA.
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Abstract
Awareness of the importance of sleep-related disorders in patients with cardiovascular diseases is growing. In particular, sleep-disordered breathing, short sleep time, and low sleep quality are frequently reported by patients with heart failure (HF). Sleep-disordered breathing, which includes obstructive sleep apnoea (OSA) and central sleep apnoea (CSA), is common in patients with HF and has been suggested to increase the morbidity and mortality in these patients. Both OSA and CSA are associated with increased sympathetic activation, vagal withdrawal, altered haemodynamic loading conditions, and hypoxaemia. Moreover, OSA is strongly associated with arterial hypertension, the most common risk factor for cardiac hypertrophy and failure. Intrathoracic pressure changes are also associated with OSA, contributing to haemodynamic alterations and potentially affecting overexpression of genes involved in ventricular remodelling. HF treatment can decrease the severity of both OSA and CSA. Indeed, furosemide and spironolactone administration, exercise training, cardiac resynchronization therapy, and eventually heart transplantation have shown a positive effect on OSA and CSA in patients with HF. At present, whether CSA should be treated and, if so, which is the optimal therapy is still debated. By contrast, more evidence is available on the beneficial effects of OSA treatment in patients with HF.
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Pathophysiology of central sleep apneas. Sleep Breath 2016; 20:467-82. [DOI: 10.1007/s11325-015-1290-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 11/10/2015] [Accepted: 11/23/2015] [Indexed: 11/26/2022]
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15
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Koo JM, Han SH, Lee SA. Severe Central Sleep Apnea/Hypopnea Syndrome Mimicking Rapid Eye Movement Sleep Behavior Disorder. SLEEP MEDICINE RESEARCH 2015. [DOI: 10.17241/smr.2015.6.2.77] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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16
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Mansukhani MP, Wang S, Somers VK. Sleep, death, and the heart. Am J Physiol Heart Circ Physiol 2015; 309:H739-49. [PMID: 26188022 DOI: 10.1152/ajpheart.00285.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 07/13/2015] [Indexed: 12/17/2022]
Abstract
Obstructive and central sleep apnea have been associated with increased risk of adverse cardiovascular events and mortality. Sympathetic dysregulation occurring as a result of the respiratory disturbance is thought to play a role in this increased risk. Sleep apnea increases the risk of arrhythmias, myocardial ischemia/infarction, stroke, and heart failure, all of which may increase mortality risk. A higher incidence of nocturnal arrhythmias, cardiac ischemia, and sudden death has been noted in subjects with sleep-disordered breathing (SDB). In this review, the association between SDB and each of these conditions is discussed, as well as the potential mechanisms underlying these risks and the effects of treatment of SDB. Particular emphasis is placed on the relationship between SDB and nocturnal atrial and ventricular arrhythmias, myocardial ischemia/infarction and sudden death.
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Affiliation(s)
- Meghna P Mansukhani
- Sleep Medicine, Affiliated Community Medical Centers, Willmar, Minnesota; and
| | - Shihan Wang
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Virend K Somers
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
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Abstract
Congestive heart failure (CHF) is among the most common causes of admission to hospitals in the United States, especially in those over age 65. Few data exist regarding the prevalence CHF of Cheyne-Stokes respiration (CSR) owing to congestive heart failure in the intensive care unit (ICU). Nevertheless, CSR is expected to be highly prevalent among those with CHF. Treatment should focus on the underlying mechanisms by which CHF increases loop gain and promotes unstable breathing. Few data are available to determine prevalence of CSR in the ICU, or how CSR might affect clinical management and weaning from mechanical ventilation.
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Affiliation(s)
- Scott A Sands
- Division of Sleep Medicine, Brigham and Women's Hospital and Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA; Department of Allergy, Immunology and Respiratory Medicine and Central Clinical School, Alfred Hospital and Monash University, 55 Commercial Rd, Melbourne, VIC 3004, Australia
| | - Robert L Owens
- Division of Pulmonary and Critical Care Medicine, University of California San Diego, 9300 Campus Point Drive, #7381, La Jolla, CA 92037, USA.
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Heart Failure and Sleep Apnea. Can J Cardiol 2015; 31:898-908. [PMID: 26112300 DOI: 10.1016/j.cjca.2015.04.017] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/23/2015] [Accepted: 04/12/2015] [Indexed: 12/18/2022] Open
Abstract
Obstructive and central sleep apnea are far more common in heart failure patients than in the general population and their presence might contribute to the progression of heart failure by exposing the heart to intermittent hypoxia, increased preload and afterload, sympathetic nervous system activation, and vascular endothelial dysfunction. There is now substantial evidence that supports a role for fluid overload and nocturnal rostral fluid shift from the legs as unifying mechanisms in the pathogenesis of obstructive and central sleep apnea in heart failure patients, such that the predominant type of sleep apnea is related to the relative distribution of fluid from the leg to the neck and chest. Despite advances in therapies for heart failure, mortality rates remain high. Accordingly, the identification and treatment of sleep apnea in patients with heart failure might offer a novel therapeutic target to modulate this increased risk. In heart failure patients with obstructive or central sleep apnea, continuous positive airway pressure has been shown to improve cardiovascular function in short-term trials but this has not translated to improved mortality or reduced hospital admissions in long-term randomized trials. Other forms of positive airway pressure such as adaptive servoventilation have shown promising results in terms of attenuation of sleep apnea and improvement in cardiovascular function in short-term trials. Large scale, randomized trials are required to determine whether treating sleep apnea with various interventions can reduce morbidity and mortality.
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Heart rate variability is augmented in patients with positional obstructive sleep apnea, but only supine LF/HF index correlates with its severity. Sleep Breath 2014; 19:359-67. [PMID: 25012091 DOI: 10.1007/s11325-014-1029-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 06/01/2014] [Accepted: 06/30/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE Data on cardiac autonomic functioning, as expressed by heart rate variability (HRV), in patients with positional obstructive sleep apnea (p-OSA) disorder are lacking. The purpose of the study was to compare HRV indices between sleep segments derived from supine body position and another body position with and without apneic events, respectively. Our intention was to find some correlation between HRV indices and the pathophysiological characteristics of the corresponding temporal period. METHODS Nocturnal polysomnograms derived from twenty-seven patients (22 men) with documented positional apnea were retrospectively reviewed. Patients never treated for OSA and free from diseases/drugs altering HRV were examined. Data from total sleep studies were collected. Two N2 sleep segments, from supine body position with sleep-disordered breathing (SDB) and another body position without SDB were analyzed. Apneic events (namely, apneas, hypopneas, and respiratory effort-related arousals (RERAs)), arousals, number of desaturations, minimum pulse oximetry (SaO2min), time domain variables (average RR, SDNN, SDSD, RMSSD, pNN50, and HRV triangular index) and frequency domain variables (VLF, LF, HF, TP, LF/HF) were recorded for both temporal periods. RESULTS With the exception of average RR and HF, all other variables were significantly higher in segments with SDB. Only LF/HF_supine ratio was positively correlated with the apneic_supine_index (t = 3.13, p < 0.01) and negatively correlated with SaO2min (t = -2.9, p < 0.01) and the desaturation_supine_index (t = -2.5, p = 0.02). Arousals were negatively correlated with SaO2min (t = -2.8, p < 0.01). CONCLUSIONS SDB augments autonomic tone in patients with p-OSA, but only LF/HF correlates with its severity and might be used as a screening tool in the future. On the contrary, parasympathetic tone, as reflected by HF, remains constant in both periods.
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20
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Padeletti M, Zacà V, Mondillo S, Jelic S. Sleep-disordered breathing increases the risk of arrhythmias. J Cardiovasc Med (Hagerstown) 2014; 15:411-6. [PMID: 24743686 PMCID: PMC4654124 DOI: 10.2459/jcm.0000000000000019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Sleep-disordered breathing (SDB) has been consistently associated with increased risk for cardiovascular diseases, including arrhythmias. The purpose of this review is to elucidate the several pathophysiologic pathways such as repetitive hypoxia and reoxygenation, increased oxidative stress, inflammation and sympathetic activation that may underlie the increased incidence of arrhythmias in SDB patients. We discuss in particular the incidence of ventricular arrhythmias, atrial fibrillation and bradyarrhythmias in SDB patients. In addition, we discuss the electrocardiographic alteration such as ST-T changes during apneic events and QT dispersion induced by SDB that may trigger complex ventricular arrhythmias and sudden cardiac death. Finally, we consider also the therapeutic interventions such as continuous positive airways pressure therapy, a standard treatment for SDB, that may reduce the incidence and recurrence of supraventricular and ventricular arrhythmias in patients with SDB.
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Affiliation(s)
| | - Valerio Zacà
- Department of Cardiovascular Diseases, University of Siena, Siena, Italy
| | - Sergio Mondillo
- Department of Cardiovascular Diseases, University of Siena, Siena, Italy
| | - Sanja Jelic
- Division of Pulmonary, Allergy, and Critical Care Medicine, Columbia University College of Physicians and Surgeons, New York, USA
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Domenico Pinna G, Robbi E, Pizza F, Caporotondi A, La Rovere MT, Maestri R. Sleep-wake fluctuations and respiratory events during Cheyne-Stokes respiration in patients with heart failure. J Sleep Res 2013; 23:347-57. [DOI: 10.1111/jsr.12109] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 10/12/2013] [Indexed: 11/27/2022]
Affiliation(s)
- Gian Domenico Pinna
- Department of Biomedical Engineering; Fondazione S. Maugeri - IRCCS; Montescano Italy
| | - Elena Robbi
- Sleep Laboratory; Department of Pneumology; Fondazione S. Maugeri - IRCCS; Montescano Italy
- Department of Cardiology; Fondazione S. Maugeri - IRCCS; Montescano Italy
| | - Fabio Pizza
- Department of Biomedical and Neuromotor Sciences (DIBINEM); University of Bologna; Bologna Italy
- Istituto delle Scienze Neurologiche di Bologna - IRCCS; AUSL di Bologna; Bologna Italy
| | - Angelo Caporotondi
- Department of Cardiology; Fondazione S. Maugeri - IRCCS; Montescano Italy
| | | | - Roberto Maestri
- Department of Biomedical Engineering; Fondazione S. Maugeri - IRCCS; Montescano Italy
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Schmalgemeier H, Bitter T, Fischbach T, Horstkotte D, Oldenburg O. C-reactive protein is elevated in heart failure patients with central sleep apnea and Cheyne-Stokes respiration. ACTA ACUST UNITED AC 2013; 87:113-20. [PMID: 23988380 DOI: 10.1159/000351115] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 03/30/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND Manifestation of central sleep apnea (CSA) with Cheyne-Stokes respiration is of major prognostic impact in chronic heart failure (CHF). Inflammatory processes have been linked to a progression of cardiovascular diseases, including heart failure. While an association of C-reactive protein (CRP) levels to obstructive sleep apnea has been documented before, there is a lack of information regarding variation of CRP levels in patients with CSA. OBJECTIVES The objective of this study was to investigate a potential association of CRP levels to CSA severity in CHF patients. METHODS High sensitivity CRP levels were analyzed in 966 patients with CHF (BMI 26.3 ± 4.6, New York Heart Association class 2.6 ± 0.5, left ventricular ejection fraction 29.4 ± 7.9%, N-terminal pro-brain natriuretic peptide, NT-proBNP, level 2,209 ± 3,315 pg/ml) without sleep-disordered breathing (SDB; Apnea-Hypopnea Index, AHI, <5/h) or various degrees of CSA, documented by in-hospital cardiorespiratory polygraphy or polysomnography. RESULTS The CRP concentration in CHF patients was 0.550 ± 0.794 mg/dl in patients without SDB (AHI 0-4/h, n = 403) versus 0.488 ± 0.708 mg/dl in patients with mild CSA (AHI 5-14/h, n = 123, p = n.s.) and 0.660 ± 0.963 mg/dl in patients with moderate CSA (AHI 15-29/h, n = 160, p = n.s.). In patients with severe CSA (AHI ≥ 30/h, n = 280), significantly higher CRP concentrations were documented (0.893 ± 1.384 mg/dl, p < 0.05). Stepwise regression analysis revealed AHI, NT-proBNP and heart rate to be independently associated with elevated CRP levels. CONCLUSION Severe CSA in CHF patients is associated with elevated levels of CRP, a systemic marker of inflammation and cardiovascular risk. This might explain in part the negative prognostic impact of CSA in these patients.
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Affiliation(s)
- Heidi Schmalgemeier
- Department of Cardiology, Heart and Diabetes Centre North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany
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Simms T, Brijbassi M, Montemurro LT, Bradley TD. Differential timing of arousals in obstructive and central sleep apnea in patients with heart failure. J Clin Sleep Med 2013; 9:773-9. [PMID: 23946707 PMCID: PMC3716668 DOI: 10.5664/jcsm.2918] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
STUDY OBJECTIVES In obstructive sleep apnea (OSA), arousals generally occur at apnea termination and help restore airflow. However, timing of arousals in central sleep apnea (CSA) has not been objectively quantified, and since arousals can persist even when CSA is alleviated, may not play the same defensive role as they do in OSA. We hypothesized that arousals following central events would occur longer after event termination than following obstructive events and would be related to circulation time. METHODS We examined polysomnograms from 20 patients with heart failure (HF) (left ventricular ejection fraction ≤ 45%): 10 with OSA and 10 with CSA (apneahypopnea index ≥ 15). Twenty central or obstructive apneas or hypopneas were analyzed in each patient. RESULTS Compared to the OSA group in whom arousals generally occurred at obstructive event termination, in the CSA group they occurred longer after central event termination (0.9 ± 1.1 versus 8.0 ± 4.1 s, p < 0.0001), but before peak hyperpnea. Time from arousal to peak hyperpnea did not differ between groups (4.3 ± 1.1 vs 4.8 ± 1.6 s, p = 0.416). Unlike the OSA group, latency from apnea termination to arousal correlated with circulation time in the CSA group (r = 0.793, p = 0.006). CONCLUSIONS In HF patients with CSA, apnea-to-arousal latency is longer than in those with OSA, and arousals usually follow resumption of airflow. These observations provide evidence that arousals are less likely to act as a protective mechanism to facilitate resumption of airflow following apneas in CSA than in OSA.
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Affiliation(s)
- Taryn Simms
- Sleep Research Laboratories of the University Health Network Toronto Rehabilitation Institute and Toronto General Hospital, Toronto, ON, Canada
| | - Melissa Brijbassi
- Sleep Research Laboratories of the University Health Network Toronto Rehabilitation Institute and Toronto General Hospital, Toronto, ON, Canada
| | - Luigi Taranto Montemurro
- Sleep Research Laboratories of the University Health Network Toronto Rehabilitation Institute and Toronto General Hospital, Toronto, ON, Canada
| | - T. Douglas Bradley
- Sleep Research Laboratories of the University Health Network Toronto Rehabilitation Institute and Toronto General Hospital, Toronto, ON, Canada
- Centre for Sleep Medicine and Circadian Biology of the University of Toronto, Toronto, ON, Canada
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Plataki M, Sands SA, Malhotra A. Clinical consequences of altered chemoreflex control. Respir Physiol Neurobiol 2013; 189:354-63. [PMID: 23681082 DOI: 10.1016/j.resp.2013.04.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 04/19/2013] [Accepted: 04/25/2013] [Indexed: 01/28/2023]
Abstract
Control of ventilation dictates various breathing patterns. The respiratory control system consists of a central pattern generator and several feedback mechanisms that act to maintain ventilation at optimal levels. The concept of loop gain has been employed to describe its stability and variability. Synthesizing all interactions under a general model that could account for every behavior has been challenging. Recent insight into the importance of these feedback systems may unveil therapeutic strategies for common ventilatory disturbances. In this review we will address the major mechanisms that have been proposed as mediators of some of the breathing patterns in health and disease that have raised controversies and discussion on ventilatory control over the years.
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Affiliation(s)
- Maria Plataki
- Department of Internal Medicine, Bridgeport Hospital, Yale New Haven Health, Bridgeport, CT, USA
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Mehta V, Vasu TS, Phillips B, Chung F. Obstructive sleep apnea and oxygen therapy: a systematic review of the literature and meta-analysis. J Clin Sleep Med 2013; 9:271-9. [PMID: 23493498 DOI: 10.5664/jcsm.2500] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Hypoxemia is an immediate consequence of obstructive sleep apnea. Oxygen (O2) administration has been used as an alternative treatment in patients with obstructive sleep apnea (OSA) who do not adhere to continuous positive airway pressure (CPAP) in order to reduce the deleterious effects of intermittent hypoxemia during sleep. This systematic review aims to investigate the effects of O2 therapy on patients with OSA. METHOD We conducted a systematic search of the databases Medline, Embase, Cochrane Central Register of Controlled Trials (1(st) Quarter 2011), Cochrane Database of Systematic Reviews (from 1950 to February 2011). Our search strategy yielded 4,793 citations. Irrelevant papers were excluded by title and abstract review, leaving 105 manuscripts. We reviewed all prospective studies that included: (1) a target population with obstructive sleep apnea, (2) O2 therapy and/or CPAP as a study intervention, (3) the effects of O2 on the apnea-hypopnea index (AHI), nocturnal hypoxemia, or apnea duration. RESULTS We identified 14 studies including a total of 359 patients. Nine studies were of single cohort design, while 5 studies were randomized control trials with 3 groups (CPAP, oxygen, and placebo/sham CPAP). When CPAP was compared to O2 therapy, all but one showed a significant improvement in AHI. Ten studies demonstrated that O2 therapy improved oxygen saturation vs. placebo. However, the average duration of apnea and hypopnea episodes were longer in patients receiving O2 therapy than those receiving placebo. CONCLUSION This review shows that O2 therapy significantly improves oxygen saturation in patients with OSA. However, it may also increase the duration of apnea-hypopnea events.
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Affiliation(s)
- Vanita Mehta
- Department of Anesthesiology, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Canada
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Kasai T, Motwani SS, Yumino D, Gabriel JM, Montemurro LT, Amirthalingam V, Floras JS, Bradley TD. Contrasting effects of lower body positive pressure on upper airways resistance and partial pressure of carbon dioxide in men with heart failure and obstructive or central sleep apnea. J Am Coll Cardiol 2013; 61:1157-66. [PMID: 23375931 DOI: 10.1016/j.jacc.2012.10.055] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 10/23/2012] [Accepted: 10/28/2012] [Indexed: 11/26/2022]
Abstract
OBJECTIVES This study sought to test the effects of rostral fluid displacement from the legs on transpharyngeal resistance (Rph), minute volume of ventilation (Vmin), and partial pressure of carbon dioxide (PCO2) in men with heart failure (HF) and either obstructive (OSA) or central sleep apnea (CSA). BACKGROUND Overnight rostral fluid shift relates to severity of OSA and CSA in men with HF. Rostral fluid displacement may facilitate OSA if it shifts into the neck and increases Rph, because pharyngeal obstruction causes OSA. Rostral fluid displacement may also facilitate CSA if it shifts into the lungs and induces reflex augmentation of ventilation and reduces PCO2, because a decrease in PCO2 below the apnea threshold causes CSA. METHODS Men with HF were divided into those with mainly OSA (obstructive-dominant, n = 18) and those with mainly CSA (central-dominant, n = 10). While patients were supine, antishock trousers were deflated (control) or inflated for 15 min (lower body positive pressure [LBPP]) in random order. RESULTS LBPP reduced leg fluid volume and increased neck circumference in both obstructive- and central-dominant groups. However, in contrast to the obstructive-dominant group in whom LBPP induced an increase in Rph, a decrease in Vmin, and an increase in PCO2, in the central-dominant group, LBPP induced a reduction in Rph, an increase in Vmin, and a reduction in PCO2. CONCLUSIONS These findings suggest mechanisms by which rostral fluid shift contributes to the pathogenesis of OSA and CSA in men with HF. Rostral fluid shift could facilitate OSA if it induces pharyngeal obstruction, but could also facilitate CSA if it augments ventilation and lowers PCO2.
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Affiliation(s)
- Takatoshi Kasai
- Sleep Research Laboratory of the Toronto Rehabilitation Institute, University of Toronto, Toronto, Ontario, Canada
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Chouvarda I, Rosso V, Mendez MO, Bianchi AM, Parrino L, Grassi A, Terzano M, Cerutti S. Assessment of the EEG complexity during activations from sleep. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2011; 104:e16-e28. [PMID: 21156327 DOI: 10.1016/j.cmpb.2010.11.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 10/30/2010] [Accepted: 11/09/2010] [Indexed: 05/30/2023]
Abstract
The present study quantitatively analyzes the EEG characteristics during activations (Act) that occur during NREM sleep, and constitute elements of sleep microstructure (i.e. the Cyclic Alternating Pattern). The fractal dimension (FD) and the sample entropy (SampEn) measures were used to study the different sleep stages and the Act that build up the sleep structure. Polysomnographic recordings from 10 good sleepers were analyzed. The complexity indexes of the Act were compared with the non-activation (NAct) periods during non-REM sleep. In addition, complexity measures among the different Act subtypes (A1, A2 and A3) were analyzed. A3 presented a quite similar complexity independently of the sleep stage, while A1 and A2 showed higher complexity in light sleep than during deep sleep. The current results suggest that Act present a hierarchic complexity between subtypes A3 (higher), A2 (intermediate) and A1 (lower) in all sleep stages.
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Affiliation(s)
- I Chouvarda
- Lab of Medical Informatics, The Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece.
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28
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Mechanisms of sleep-disordered breathing: causes and consequences. Pflugers Arch 2011; 463:213-30. [DOI: 10.1007/s00424-011-1055-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 10/14/2011] [Accepted: 10/26/2011] [Indexed: 11/27/2022]
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Sands SA, Edwards BA, Kee K, Turton A, Skuza EM, Roebuck T, O'Driscoll DM, Hamilton GS, Naughton MT, Berger PJ. Loop Gain As a Means to Predict a Positive Airway Pressure Suppression of Cheyne-Stokes Respiration in Patients with Heart Failure. Am J Respir Crit Care Med 2011; 184:1067-75. [DOI: 10.1164/rccm.201103-0577oc] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Delisle S, Ouellet P, Bellemare P, Tétrault JP, Arsenault P. Sleep quality in mechanically ventilated patients: comparison between NAVA and PSV modes. Ann Intensive Care 2011; 1:42. [PMID: 21955588 PMCID: PMC3224529 DOI: 10.1186/2110-5820-1-42] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 09/28/2011] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Mechanical ventilation seems to occupy a major source in alteration in the quality and quantity of sleep among patients in intensive care. Quality of sleep is negatively affected with frequent patient-ventilator asynchronies and more specifically with modes of ventilation. The quality of sleep among ventilated patients seems to be related in part to the alteration between the capacities of the ventilator to meet patient demand. The objective of this study was to compare the impact of two modes of ventilation and patient-ventilator interaction on sleep architecture. METHODS Prospective, comparative crossover study in 14 conscious, nonsedated, mechanically ventilated adults, during weaning in a university hospital medical intensive care unit. Patients were successively ventilated in a random ordered cross-over sequence with neurally adjusted ventilatory assist (NAVA) and pressure support ventilation (PSV). Sleep polysomnography was performed during four 4-hour periods, two with each mode in random order. RESULTS The tracings of the flow, airway pressure, and electrical activity of the diaphragm were used to diagnose central apneas and ineffective efforts. The main abnormalities were a low percentage of rapid eye movement (REM) sleep, for a median (25th-75th percentiles) of 11.5% (range, 8-20%) of total sleep, and a highly fragmented sleep with 25 arousals and awakenings per hour of sleep. Proportions of REM sleep duration were different in the two ventilatory modes (4.5% (range, 3-11%) in PSV and 16.5% (range, 13-29%) during NAVA (p = 0.001)), as well as the fragmentation index, with 40 ± 20 arousals and awakenings per hour in PSV and 16 ± 9 during NAVA (p = 0.001). There were large differences in ineffective efforts (24 ± 23 per hour of sleep in PSV, and 0 during NAVA) and episodes of central apnea (10.5 ± 11 in PSV vs. 0 during NAVA). Minute ventilation was similar in both modes. CONCLUSIONS NAVA improves the quality of sleep over PSV in terms of REM sleep, fragmentation index, and ineffective efforts in a nonsedated adult population.
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Affiliation(s)
- Stéphane Delisle
- Service des soins intensifs, Hôpital du Sacré-Cœur de Montréal, Montréal, Québec, Canada
- Département de médecine familiale et d'urgence, Université de Montréal, Montréal, Québec, Canada
- Département des sciences cliniques, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Paul Ouellet
- Département des sciences cliniques, Université de Sherbrooke, Sherbrooke, Québec, Canada
- Département de chirurgie, Centre hospitalier universitaire de Sherbrooke, Sherbrooke, Québec, Canada
- Service des soins intensifs, Hôpital régional d'Edmundston, réseau de santé Vitalité, Edmundston, Nouveau-Brunswick, Canada
| | - Patrick Bellemare
- Service des soins intensifs, Hôpital du Sacré-Cœur de Montréal, Montréal, Québec, Canada
| | - Jean-Pierre Tétrault
- Département des sciences cliniques, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Pierre Arsenault
- Département des sciences cliniques, Université de Sherbrooke, Sherbrooke, Québec, Canada
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Abstract
It is increasingly recognized that sleep-disordered breathing (SDB) is a common modifiable risk factor for cardiovascular disease with significant impact on morbidity and potentially mortality. SDB is highly prevalent in patients with systolic or diastolic heart failure. A high index of suspicion is necessary to diagnose SDB in patients with heart failure because the vast majority of affected patients do not report daytime symptoms. Recent clinical trials have demonstrated improvement in heart function, exercise tolerance, and quality of life after treatment of SDB in patients with heart failure. Accumulating evidence suggests that treatment of SDB should complement the established pharmacologic therapy for chronic heart failure. However, mortality benefit has yet to be demonstrated.
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Bitter T, Westerheide N, Prinz C, Hossain MS, Vogt J, Langer C, Horstkotte D, Oldenburg O. Cheyne-Stokes respiration and obstructive sleep apnoea are independent risk factors for malignant ventricular arrhythmias requiring appropriate cardioverter-defibrillator therapies in patients with congestive heart failure. Eur Heart J 2010; 32:61-74. [PMID: 20846992 DOI: 10.1093/eurheartj/ehq327] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Thomas Bitter
- Department of Cardiology, Heart and Diabetes Centre North Rhine-Westphalia, Ruhr University Bochum, Georgstasse 11, Bad Oeynhausen, Germany.
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Foo JYA, Wilson SJ. Clinical applications of pulse transit time in paediatric critical care. J Med Eng Technol 2009; 33:79-86. [PMID: 19116857 DOI: 10.1080/03091900701860210] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A simple and non-invasive technique, termed pulse transit time (PTT), has shown its potential in long-term investigations such as respiratory sleep studies and cardiovascular studies. Based on these findings, the PTT technique shows relevance for continuous haemodynamic monitoring in critical care. The objective of this review is to understand the potential, applications and limitations of PTT in this clinical setting. Present non-invasive haemodynamic monitoring methods such as automated oscillometric blood pressure (BP) and auscultatory techniques have their known limitations. They tend to underestimate systolic BP while overestimating diastolic BP. Due to the periodic increase in cuff pressure cycles during data acquisition, these techniques may cause much discomfort in elderly geriatric patients, or lessen the cooperation of younger paediatric patients. Thus, there can be adverse effects on therapeutic decisions and possibly clinical outcomes. Documented evidences have indicated that changes observed in PTT are inversely correlated to the corresponding BP changes. In critical care, a simple and accommodating technique like PTT may be useful in providing better comfort for patients during extended monitoring. Being a semi-quantitative measure, blanket recommendations for its utility can then become possible. The basic instrumentations needed are often part of standard critical care monitoring system. Furthermore, PTT also has the potential to monitor the often tachypnoeic respiratory dependent BP changes seen in small infants during critical care.
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Affiliation(s)
- J Y A Foo
- Division of Research, Singapore General Hospital, Singapore.
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Foo JYA, Lim CS. An investigation on pulse transit time in respiratory sleep studies for infants. J Med Eng Technol 2009; 32:245-9. [DOI: 10.1080/03091900600863463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Hamilton GS, Meredith IT, Walker AM, Solin P. Obstructive sleep apnea leads to transient uncoupling of coronary blood flow and myocardial work in humans. Sleep 2009; 32:263-70. [PMID: 19238814 DOI: 10.1093/sleep/32.2.263] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
STUDY OBJECTIVES Obstructive Sleep Apnea (OSA) is associated with a poor prognosis in patients with coronary artery disease. We hypothesized that abnormalities of coronary blood flow (CBF) associated with obstructive apneas may predispose patients to ischemia. We aimed to determine CBF during respiratory events in patients with OSA. SETTING University Hospital. PATIENTS Ten subjects undergoing elective percutaneous coronary intervention DESIGN We measured CBF and myocardial work (rate-pressure product [RPP]) in a non-culprit coronary artery in patients sleeping in the cardiac catheterization laboratory. Hemodynamic responses were matched to spontaneously occurring respiratory events. MEASUREMENTS AND RESULTS Events comprised a mixture of obstructive apneas, central apneas and hypopneas. RPP increased at the termination of each type of respiratory event. Following the rise in RPP, there was a delay, identified with breakpoint analysis, before CBF began to increase (P<0.001) that differed in duration with event type: 8 sec for obstructive apnea, 5 sec for central apnea, and 4 sec for hypopnea. The delay in CBF with obstructive apnea was associated with an increase in coronary vascular resistance of 16% +/- 4% (P < 0.05). Stepwise multilinear regression analysis showed the increase in CBF was predicted by the rise in RPP (R=0.52, P<0.001) and presence of arousal from sleep (R=0.30, P<0.05), but not the degree of O2 desaturation. CONCLUSION Following obstructive apneas there is a transient uncoupling of CBF from myocardial work and an increase in CVR. This disturbed flow-metabolic coupling may lead to nocturnal myocardial ischemia in patients with both OSA and coronary artery disease.
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Affiliation(s)
- Garun S Hamilton
- Department of Medicine, Monash Medical Centre, Clayton, Victoria, Australia
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Abstract
This paper focuses on the underlying mechanisms contributing to sleep-disordered breathing. Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by repetitive narrowing or collapse of the pharyngeal airway during sleep. Conversely, central sleep apnea (CSA), highly prevalent in congestive heart failure, is distinguished by a lack of drive to breathe during sleep, resulting in repetitive periods of insufficient ventilation. Both lead to compromised gas exchange, impaired sleep continuity, and catecholamine surges and are associated with major comorbidities including excessive daytime sleepiness and increased risk of cardiovascular disease. Although OSA and CSA exist on a spectrum of sleep-disordered breathing, the 2 entities may overlap in their underlying pathophysiologies. This brief review summarizes the etiology and current understanding of OSA and CSA pathophysiology and the role that the cardiovascular system may play in contributing to disease pathology and highlights the likely substantial overlap that exists between the various forms of sleep-disordered breathing.
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Abstract
Obstructive sleep apnea (OSA) is present in at least 2% to 4% of the general population. Central sleep apnea (CSA), though less common, is highly prevalent in patients with heart failure. Both forms of sleep apnea exert strong modulatory effects on the autonomic nervous system at night through a number of mechanisms including central respiratory-cardiac coupling in the brainstem, chemoreflex stimulation, baroreflexes, and reflexes relating to lung inflation. Arousals also contribute to the autonomic disturbance. Although sleep is normally a time when parasympathetic modulation of the heart predominates and myocardial electrical stability is enhanced, OSA and CSA disturb this quiescence, creating an autonomic profile in which both profound vagal activity leading to bradyarrhythmias, and sympatho-excitation favoring ventricular ectopy are observed. The resulting tendency toward cardiac arrhythmia may directly contribute to sudden cardiac death and premature mortality in patients with sleep apnea. Therapy consists largely of treatment with continuous positive airway pressure, which has been shown to improve autonomic profile and reduce nocturnal arrhythmias.
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Foo JYA, Wilson SJ, Lim CS. Use of the pulse transit time trend to relate tidal breathing and central respiratory events. Proc Inst Mech Eng H 2008; 222:1005-11. [PMID: 18935818 DOI: 10.1243/09544119jeim395] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Central sleep apnoea (CSA) is a respiratory event where cessation of breathing effort and airflow occurs. Numerous lumped models have related the physical phenomena in the arterial tree to properties of the arterial wall. However, a limited model is available that describes pulse transit time (PTT) oscillations during CSA and tidal breathing. Data from 28 children (22 males; aged 6.2 +/- 3.6 years) were obtained during overnight polysomnography. Using a lumped-element model, PTT fluctuations during both respiratory events were described and compared with actual experimental data. 222 valid CSA and 222 tidal breathing events were acquired and analysed. For the tidal breathing, undamped PTT oscillations of 3.89 s were predicted while actual data showed a mean value of 3.68 +/- 0.83 s. Conversely, a damped PTT trend was observed during CSA as predicted by the model. The results attained showed that clustered CSA occurrences led to an increase of 7.23 +/- 3.34 per cent in PTT baseline value while the model predicted 7.86 +/- 2.63 per cent. The marginal increase in PTT baseline was expected since the blood pressure and heart rate decreased during such occurrences. The findings herein suggest that the described model has the potential to describe respiratory event characteristics of a sleeping child.
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Affiliation(s)
- J Y A Foo
- Division of Research, Singapore General Hospital, Singapore, Singapore.
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Sleep quality in mechanically ventilated patients: Comparison of three ventilatory modes. Crit Care Med 2008; 36:1749-55. [DOI: 10.1097/ccm.0b013e3181743f41] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ryan CM, Juvet S, Leung R, Bradley TD. Timing of Nocturnal Ventricular Ectopy in Heart Failure Patients With Sleep Apnea. Chest 2008; 133:934-40. [DOI: 10.1378/chest.07-2595] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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42
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On arousal from sleep: time-frequency analysis. Med Biol Eng Comput 2008; 46:341-51. [DOI: 10.1007/s11517-008-0309-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2006] [Accepted: 01/21/2008] [Indexed: 11/26/2022]
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Willson GN, Grunstein RR, Kirjavainen T, Young IH, Piper AJ, Sullivan CE, Wilcox I. Electroencephalographic arousals during sleep do not alter the pressor response to Cheyne-Stokes respiration in subjects with chronic heart failure. J Sleep Res 2007; 16:421-7. [PMID: 18036088 DOI: 10.1111/j.1365-2869.2007.00616.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study examined the influence of electroencephalographic (EEG) arousal on the magnitude and morphology of the pressor response to Cheyne-Stokes respiration (CSR) in subjects with congestive heart failure (CHF). Thirteen subjects with stable CHF (left ventricular ejection fraction, 26 +/- 7%) and CSR (apnea-hypopnea index 52 +/- 15 h(-1)) underwent overnight polysomnography with beat-to-beat measurement of systemic arterial blood pressure (BP). CSR events were divided into those with or without an EEG arousal defined according to the criteria of the American Sleep Disorders Association. The pressor response was quantified in terms of the delta BP change (difference between the minimum BP during apnea and maximum BP during hyperpnea). Changes in the morphology of the pressor response were assessed by subdividing individual respiratory events into six periods (three during apnea: A1, A2, A3; and three during hyperpnea: H1, H2, H3). Considerable fluctuations in BP and heart rate (HR) were observed across the CSR cycle (delta mean BP 20.2 +/- 6.5 mmHg). The presence of an EEG arousal did not alter the amplitude of fluctuations in BP. Mean blood pressure (MBP) increased 21.0 +/- 7.5 mmHg with arousal versus 19.3 +/- 5.8 mmHg without arousal (NS). A repeated measures ANOVA showed no significant interaction between the presence of arousal and the proportional change in mean BP across the six periods, indicating that an EEG arousal had no effect on the morphology of MBP change during CSR [F(5,60) = 1.44, P = 0.22]. This study showed that EEG-defined arousal does not amplify the pressor response to CSR in CHF.
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Affiliation(s)
- Grant N Willson
- Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Missenden Road, Camperdown, Sydney, NSW 2050, Australia.
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Cabello B, Parthasarathy S, Mancebo J. Mechanical ventilation: let us minimize sleep disturbances. Curr Opin Crit Care 2007; 13:20-6. [PMID: 17198045 DOI: 10.1097/mcc.0b013e3280121adc] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW This review provides a background in mechanical ventilation and sleep. RECENT FINDINGS Sleep pattern in mechanically ventilated patients differs largely from physiological sleep. The ventilatory mode and the ventilatory settings could have an influence on the sleep quality and quantity. Pressure support ventilation can increase the sleep fragmentation and decrease the sleep quantity, due to central apneas when compared with assist control ventilation. An excessive level of ventilatory assistance during sleep promotes central apneas and ineffective efforts. These two respiratory events can trigger arousals and awakenings, thus altering the sleep quality and quantity in mechanically ventilated patients. Ventilatory settings adjusted according to the patient's effort during pressure support allow reducing the number of ineffective efforts and improve sleep quality when compared with a clinical adjustment. A physiological approach to set the ventilator and the ventilatory mode may improve sleep quality and quantity. SUMMARY Minimizing the sleep alterations in mechanically ventilated patients could be obtained by setting the ventilator in such a way to avoid hyperventilation during the sleep stage. The impact of sleep derangements in patient outcomes is, however, unknown.
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Affiliation(s)
- Belen Cabello
- Intensive Medicine Service, Santa Creu i Sant Pau Hospital, Barcelona, Spain.
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Foo JYA, Lim CS. Changes induced in the lower- and upper-limb pulse transit-time ratio during inspiratory resistive breathing. BIOMED ENG-BIOMED TE 2007; 52:248-54. [PMID: 17561786 DOI: 10.1515/bmt.2007.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The ankle brachial index (ABI) has been widely used to monitor the pathogenesis of peripheral arterial diseases such as ischemia of the extremities. Owing to the occluding nature of ABI measurement, this may not be appealing to less cooperative patients when multiple prolonged screening is required. Recently, a simple non-occluding technique termed pulse transit-time ratio (PTTR) has shown potential as a surrogate ABI marker. It is also known that abrupt changes in inspiratory efforts can lead to increased blood pressure (BP) and heart rate. Since transit-time measurements can be confounded by these parameters, it is important to understand their effects on PTTR normality. We recruited 12 healthy adults (8 males, aged 27.0+/-3.1 years) to perform three inspiratory activities. Friedman and Wilcoxon statistical results both showed that significant changes in transit-time oscillations were observed for higher inspiratory loads (p<0.05). These results were verified by a corresponding air-pressure difference measurement, for which a similar significant increase was also registered (p<0.05). However, limited changes were observed in the derived PTTR parameter (p>0.05). These findings suggest that, similar to ABI, PTTR is only confounded by abnormal local changes in either of the peripheral BPs measured.
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Affiliation(s)
- Jong Yong Abdiel Foo
- Biomedical Engineering Research Center, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Singapore 637553.
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46
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Eckert DJ, Jordan AS, Merchia P, Malhotra A. Central sleep apnea: Pathophysiology and treatment. Chest 2007; 131:595-607. [PMID: 17296668 PMCID: PMC2287191 DOI: 10.1378/chest.06.2287] [Citation(s) in RCA: 289] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Central sleep apnea (CSA) is characterized by a lack of drive to breathe during sleep, resulting in repetitive periods of insufficient ventilation and compromised gas exchange. These nighttime breathing disturbances can lead to important comorbidity and increased risk of adverse cardiovascular outcomes. There are several manifestations of CSA, including high altitude-induced periodic breathing, idiopathic CSA, narcotic-induced central apnea, obesity hypoventilation syndrome, and Cheyne-Stokes breathing. While unstable ventilatory control during sleep is the hallmark of CSA, the pathophysiology and the prevalence of the various forms of CSA vary greatly. This brief review summarizes the underlying physiology and modulating components influencing ventilatory control in CSA, describes the etiology of each of the various forms of CSA, and examines the key factors that may exacerbate apnea severity. The clinical implications of improved CSA pathophysiology knowledge and the potential for novel therapeutic treatment approaches are also discussed.
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Affiliation(s)
- Danny J Eckert
- Division of Sleep Medicine, Sleep Disorders Program, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Vazir A, Hastings P, Dayer M, McIntyre H, Henein M, Poole-Wilson P, Cowie M, Morrell M, Simonds A. A high prevalence of sleep disordered breathing in men with mild symptomatic chronic heart failure due to left ventricular systolic dysfunction. Eur J Heart Fail 2007; 9:243-50. [DOI: 10.1016/j.ejheart.2006.08.001] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Revised: 06/14/2006] [Accepted: 08/15/2006] [Indexed: 11/26/2022] Open
Affiliation(s)
- A. Vazir
- Academic Unit of Sleep and Breathing, The Royal Brompton Hospital, National Heart and Lung Institute; Imperial College; Sydney Street London United Kingdom
- Department of Cardiac Medicine; The Royal Brompton Hospital, National Heart and Lung Institute; Imperial College; Sydney Street London United Kingdom
| | - P.C. Hastings
- Academic Unit of Sleep and Breathing, The Royal Brompton Hospital, National Heart and Lung Institute; Imperial College; Sydney Street London United Kingdom
| | - M. Dayer
- Department of Cardiac Medicine; The Royal Brompton Hospital, National Heart and Lung Institute; Imperial College; Sydney Street London United Kingdom
| | - H.F. McIntyre
- Department of Cardiology; The Conquest Hospital; The Ridge, Hastings East Sussex United Kingdom
| | - M.Y. Henein
- Department of Cardiac Medicine; The Royal Brompton Hospital, National Heart and Lung Institute; Imperial College; Sydney Street London United Kingdom
| | - P.A. Poole-Wilson
- Department of Cardiac Medicine; The Royal Brompton Hospital, National Heart and Lung Institute; Imperial College; Sydney Street London United Kingdom
| | - M.R. Cowie
- Department of Cardiac Medicine; The Royal Brompton Hospital, National Heart and Lung Institute; Imperial College; Sydney Street London United Kingdom
| | - M.J. Morrell
- Academic Unit of Sleep and Breathing, The Royal Brompton Hospital, National Heart and Lung Institute; Imperial College; Sydney Street London United Kingdom
| | - A.K. Simonds
- Academic Unit of Sleep and Breathing, The Royal Brompton Hospital, National Heart and Lung Institute; Imperial College; Sydney Street London United Kingdom
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Foo JYA, Parsley CL, Wilson SJ, Williams GR, Harris M, Cooper DM. Detection of central respiratory events using pulse transit time in infants. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2005:2579-82. [PMID: 17282765 DOI: 10.1109/iembs.2005.1616996] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The prevalence of sudden infant death syndrome (SIDS) has been well studied and central sleep apnea is deemed as one of the possible causes. Current gold standard for its diagnosis is nocturnal polysomnography (PSG). However, this procedure is complex and generally needs to be performed in a sleep laboratory. Pulse transit time (PTT) shows its potential to indicate abrupt blood pressure (BP) changes during the occurrences of upper airway obstruction. The main objective of this study was to assess the capability of PTT to differentiate central respiratory events from tidal breathing in infants. This study involved 5 infants (4 male) with mean age of 7.8 months. 50 valid central respiratory events were randomly selected. These events were free from motion artifacts and pre-scored in the corresponding PSG studies by two blinded observers. PTT measurements from these events were then evaluated against the PSG scorings. Using a two-tailed F-test for variance, it was observed that central events differed from tidal breathing in a significant manner (p<0.05). Furthermore, PTT has showed its sensitivity to monitor marginal BP fluctuations during tidal breathing. Hence, the results herein suggest that PTT can be a valuable non-invasive technique to monitor central apneic events in sleeping infants.
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Affiliation(s)
- J Y A Foo
- School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Australia 4072
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Foo JYA, Lim CS. Study of pulse transit time oscillations during obstructive sleep apnoea by using a distributed model. J Biomech 2007; 40:3289-93. [PMID: 17559857 DOI: 10.1016/j.jbiomech.2007.04.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Revised: 04/13/2007] [Accepted: 04/29/2007] [Indexed: 12/01/2022]
Abstract
The study of arterial compliance is useful in understanding the geometrical and mechanical properties of a systemic arterial tree. Numerous mathematical models have shown their potential in relating the physical phenomena in the arterial tree to properties of the wall itself. However, limited model is available that describes the pulse transit time (PTT) oscillations of a sleeping child during tidal breathing and obstructive sleep apnoea (OSA). Data from 20 children (17 male; aged 6.4 +/- 4.1 yr) whom were recruited for overnight polysomnography (PSG) were used. A modified windkessel model with related physiological parameters was utilised to describe PTT fluctuations due to the cardiovascular system during sleep. Verification with the recorded PSG data showed similar trends with the model for both types of respiratory events. For tidal breathing, undamped PTT oscillations of 3.89 s were predicted by the model while actual data yielded a mean value of 3.72 +/- 0.79 s. Conversely, under-damping PTT responses were expected based on the model for OSA. The model estimated a Q factor of 4.23 and actual mean data were 3.86 +/- 0.64. Hence, the findings herein suggest that the proposed model has the potential to illustrate tidal breathing and OSA events in sleeping children.
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Affiliation(s)
- Jong Yong Abdiel Foo
- Biomedical Engineering Research Centre, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, 6th Storey, Xfrontiers Block, Singapore 637553, Singapore.
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Trinder J, Ivens C, Kleiman J, Kleverlaan D, White DP. The cardiorespiratory activation response at an arousal from sleep is independent of the level of CO(2). J Sleep Res 2006; 15:174-82. [PMID: 16704573 DOI: 10.1111/j.1365-2869.2006.00513.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Arousal from sleep is associated with transient cardiorespiratory activation. Traditionally, this response has been understood to be a consequence of state-dependent changes in the homeostatic control of ventilation. The hypothesis predicts that the magnitude of ventilatory and cardiac responses at an arousal will be a function of the intensity of concurrent respiratory stimuli (primarily PCO(2)). Alternatively, it has been proposed that increased cardiorespiratory activity is due to reflex activation. This hypothesis predicts that the magnitude of the cardiorespiratory response will be independent of respiratory stimuli. To compare these hypotheses we measured minute ventilation (V(i)), heart rate (HR) and blood pressure (BP) during wakefulness and stage 2 sleep, while manipulating P(et)CO(2). Further, we assessed the magnitude of the response of these variables to an arousal from sleep at the various levels of P(et)CO(2). The subjects were male aged 18-25 years. P(et)CO(2) was manipulated by clamping it at four levels during wakefulness [wake eucapnic, sleep eucapnic (Low), and sleep eucapnic +3 mmHg (Medium) and +6 mmHg (High)] and three levels during sleep (Low, Medium and High). The average number of determinations for each subject at each level was 14 during wakefulness and 25 during sleep. Arousals were required to meet American Sleep Disorders Association criteria and were without body movement. The results indicated that average increases in V(i), HR and BP at arousal from sleep did not significantly differ as a function of the level of P(et)CO(2) present at the time of the arousal (all P > 0.05). Further, the magnitude of the ventilatory response to an arousal was significantly less than the values predicted by the homeostatic hypothesis (P < 0.05). We conclude that, in normal subjects, the cardiorespiratory response to an arousal from sleep is not because of a homeostatic response, but of a reflex activation.
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Affiliation(s)
- John Trinder
- Department of Psychology, University of Melbourne, Parkville, Vic. 3010, Australia.
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