Central Sleep Apnea

Results: MMT patients and normal subjects were 35 ± 9 years old (mean ± SD), and BMI values were 27 ± 6 kg/m 2 and 27 ± 5 kg/m 2 , respectively. Thirty percent of MMT patients had a central apnea index (CAI) > 5, and 20% had a CAI > 10. All normal subjects had a CAI < 1, and ...

This paper first describes the AM-FM demodulation of an arterial pressure signal. Although it is known to be efficient on signals modulated by breathing, we demonstrate that in case of lack of respiratory modulation (real or simulated central sleep apnea), the AM-FM algorithm doesn't perform well in heart rate extraction. We introduce then a new algorithm based on Singular Spectrum Analysis eigenvalues which performs better cardiac frequency estimation in this context. Respiratory estimation is possible but is beyond the scope of this paper. The error for cardiac frequency estimation is around 0.2 BPM (Beats Per Minute) versus 5.5 BPM for the AM-FM demodulation. Further experimentations will be performed (with this time both cardiac and respiratory assessments) and will deal with real sleep apnea cases.

[AMAZON LINK BELOW TO BOOK ITSELF -- TOC and book intro in downloadable .pdf]  Encyclopedia of Sleep and Dreams: The Evolution, Function, Nature, and Mysteries of Slumber explores the evolution, nature, and functions of sleep and dreams. The encyclopedia is divided into two volumes and is arranged alphabetically by entry. Topics include nightmares and their treatment, how sleep and dreams change across the lifetime, and the new field of evolution of sleep and dream. While this book includes ample material on the science of sleep and dreams, content is drawn from a broad range of disciplinary contexts, including history and anthropology.

Treatment-emergent central sleep apnea (TECSA) is a distinct form of sleep-disordered breathing characterized by the development of central sleep apnea during the initiation of positive airway pressure (PAP) therapy in patients with obstructive sleep apnea. The exact mechanisms of TECSA are not clearly known; however, several theories have been proposed. Usually, TECSA is transient and self-limited, and disappears after continued PAP use. Nevertheless, patients with persistent TECSA have lower adherence to PAP therapy and are more likely to terminate therapy. Close follow up is necessary to assure that the emergent central events disappear with continued therapy. In patients with persistent TECSA, more advanced algorithms such as adaptive servo-ventilation have been shown to be very effective. In this brief review, we summarize the definition, prevalence, predictors, pathophysi-ology, and treatment approaches of TECSA. Keywords Central sleep apnea Á Complex sleep apnea Á Treatment-emergent Á CPAP Á Adaptive servo-ventilation

Treatment-emergent central sleep apnea (TECSA) is a distinct form of sleep-disordered breathing
characterized by the development of central sleep apnea during the initiation of positive airway pressure (PAP) therapy in patients with obstructive sleep apnea. The exact mechanisms of TECSA are not clearly known; however, several theories have been proposed. Usually, TECSA is transient and self-limited, and disappears after continued PAP use. Nevertheless, patients with persistent TECSA have lower adherence to PAP therapy and are more likely to terminate therapy. Close follow up is necessary to assure that the emergent central events disappear with continued therapy. In patients with persistent TECSA, more advanced algorithms such as adaptive servo-ventilation have been shown to be very effective. In this brief review, we summarize the definition, prevalence, predictors, pathophysiology, and treatment approaches of TECSA.

Background— The prevalence and characteristics of sleep-disordered breathing in patients with asymptomatic left ventricular (LV) dysfunction are unknown. Therefore, we evaluated the prevalence of sleep-disordered breathing in patients with LV dysfunction without overt heart failure and tested the hypothesis that sleep-disordered breathing is linked to greater hemodynamic and autonomic impairment. Methods and Results— We studied 47 patients with LV ejection fractions ≤40% without any history of heart failure. Central sleep apnea (CSA), as defined by an apnea-hypopnea index ≥15/h, was present in 26 patients (55%), 17 (36%) of whom had severe CSA (apnea-hypopnea index ≥30/h). Obstructive sleep apnea was evident in 5 patients (11%). The prevalence and severity of CSA were higher in patients with ischemic cardiomyopathy than in patients with nonischemic cardiomyopathy ( P <0.05). Exercise tolerance and echocardiographic indices of systolic and diastolic function were similar in patien...

Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) is a form of periodic breathing, commonly observed in patients with heart failure (HF), in which central apneas alternate with hyperpneas that have a waxing-waning pattern of tidal volume. Uniform criteria by which to diagnose a clinically significant degree of CSR-CSA have yet to be established. CSR-CSA is caused by respiratory control system instability characterized by a tendency to hyperventilate. Central apnea occurs when Pa(CO(2)) falls below the threshold for apnea during sleep due to ventilatory overshoot. Patients with CSR-CSA are generally hypocapnic, with a Pa(CO(2)) closer than normal to the apneic threshold such that even slight augmentation in ventilation drives Pa(CO(2)) below threshold and triggers apnea. Factors contributing to hyperventilation in HF include stimulation of pulmonary irritant receptors by pulmonary congestion, increased chemoreceptor sensitivity, reduced cerebrovascular blood flow, and recu...

One month administration of acetazolamide (ACET) (at sea level) improves periodic breathing and decreases the number of central apneas (CA) (De Backer et al., 1995 Am. J. Respir. Crit. Care Med. 151, 87-91) in nonhypercapnic central apnea syndrome. It remains unclear whether cessation of therapy would provoke recurrence of symptoms. In the present study we evaluated the number of CA after 1 and 6 months interruption of ACET therapy. Eight patients with central sleep apnea were included [central apnea index (CAI) > 5 or apnea and hypopnea index (AHI) > 10 and obstructive apnea index (OAI) < 5]. Polysomnography was repeated once after 1 month treatment (N2), after 1 month off treatment (N3) and after 6 months off treatment. CAI (25 +/- 10 at N1) decreased during N2 (4 +/- 2) and N3 (5 +/- 3) and remained low after N4 (3 +/- 1). However an increase in the number of obstructive apneas and central hypopneas could be observed together with a shift from central apnea to hypopnea a...

Cheyne-Stokes respiration (CSR) is a form of central sleep-disordered breathing (SDB) in which there are cyclical fluctuations in breathing that lead to periods of central apneas/hypopnea, which alternate with periods of hyperpnea. The crescendo–decrescendo pattern of respiration in CSR is a compensation for the changing levels of blood oxygen and carbon dioxide. Severe congestive heart failure seems to be the most important risk factor for the development of CSR. A number of pathophysiologic changes, such as sleep disruption, arousals, hypoxemia-reoxygenation, hypercapnia/hypocapnia, and changes in intrathoracic pressure have harmful effects on the cardiovascular system, and the presence of CSR is associated with increased mortality and morbidity in subjects with variable degrees of heart failure. The management of CSR involves optimal control of underlying heart failure, oxygen therapy, and positive airway pressure support. In this review, we initially define and describe the epidemiology of central sleep apnea (CSA) and CSR, its pathogenesis, clinical presentation, diagnostic methods, and then discuss the recent developments in the management in patients with heart failure.

BACKGROUND: Sleep-disordered breathing (SDB) is present in more than 50% of ambulatory patients with chronic heart failure. The prevalence and type of SDB in hospitalized patients with acutely decompensated heart failure (ADHF) are not known. ...

Background —Recent studies suggest that acute pulmonary congestion induces hyperventilation and that hyperventilation-related hypocapnia leads to ventilatory control instability and central sleep apnea. Whether chronic pulmonary congestion due to congestive heart failure (CHF) is associated with central apnea is unknown. We hypothesized that CHF patients with central apnea would have greater pulmonary capillary wedge pressure (PCWP) than patients without central apnea and that PCWP would correlate with central apnea severity. Methods and Results —Seventy-five stable CHF patients underwent right heart catheterization and, on the basis of overnight sleep studies, were divided into central apnea (n=33), obstructive apnea (n=20), or nonapnea groups (apnea-hypopnea index [AHI] <5 events per hour). Mean PCWP was significantly greater in the central than in the obstructive and nonapnea groups (mean±SEM [range]: 22.8±1.2 [11 to 38] versus 12.3±1.2 [4 to 21] versus 11.5±1.5 [3 to 28] mm H...