Sleep-disordered breathing in heart failure: characteristics and implications

Unfolding the role of exercise in the management of sleep disorders

Sleep disorders are prevalent among the general population and even more in individuals suffering from chronic diseases. Recent data reveal promising effects of physical exercise as a non-pharmacological approach for improving sleep and managing various sleep disorders. However, more studies with proper design and methodology should be conducted in the future to obtain a clearer understanding of the subject. The role of exercise in preventing and improving sleep disorders is probably much higher than what is currently exploited. To fully exploit the potential benefit of physical activity on sleep disorders in the future, it is necessary to identify the relevant tools to assess sleep-wake disorders and establish specific exercise protocols tailored to different sleep disorders. The present manuscript aims to review the literature on the use of exercise in managing selected sleep disorders. Regular exercise, including short-term aerobic activity, resistance training, and mind-body exercises, can effectively improve sleep quality, particularly in cases of insomnia and sleep-disordered breathing. Additionally, increasing evidence supports the effectiveness of aerobic and strength training, and body-mind exercises such as yoga in managing sleep-related movement disorders. Exercise can be a safe, affordable, and efficient tool in enhancing sleep quality and improving sleep disorders. Per se, regular exercise could play an adjuvant role alongside with established therapies, or a valid alternative when the pharmacological approach is limited by side effects, interactions, or inefficacy. More research is needed to define how exercise affects the physiology of sleep, and consequently how to use exercise in patients with sleep disorders.

Continuous Positive Airway Pressure Adherence and Treatment Cost in Patients With Obstructive Sleep Apnea and Cardiovascular Disease

Objective

To determine whether continuous positive airway pressure (CPAP) adherence reduces health care–related costs or use in patients with obstructive sleep apnea (OSA) and comorbid cardiovascular disease (CVD).

Patients

A total of 23 million patients with CVD were identified in the Medicare fee-for-service database. Of the 65,198 who completed a sleep study between January 2016 and September 2018, 55,125 were diagnosed as having OSA and 1758 were identified in the 5% Medicare durable medical equipment (DME) database.

Methods

Patients with DME claims were categorized as adherent (AD, treatment evidenced ≥91 days after CPAP initiation; n=614) or nonadherent (nAD, n=242) to CPAP therapy. In addition, 9881 individuals with CVD who were not diagnosed as having OSA after sleep testing and without CPAP initiation were included as control patients. Propensity score matching balanced the groups for age, sex, and comorbidities (eg, diabetes mellitus), resulting in 241 participants per cohort. Dependent variables included total episode-of-care, inpatient, outpatient, skilled nursing, home health, and DME costs across 12 months.

Results

Total episode-of-care costs of AD participants ($6825) were lower than those of nAD ($11,312; P<.05) and control ($8102) participants. This difference (Δ) was attributable to fewer outpatient expenses (Δ$2290; P<.05) relative to the nAD group and fewer inpatient expenses (Δ$745) relative to the control group because skilled nursing costs were comparable between groups (P=.73).

Conclusion

Adherence to CPAP treatment reduces annual health care–related expenses by 40% in Medicare patients with CVD and OSA.

The role of declining adaptive homeostasis in ageing

Adaptive homeostasis is "the transient expansion or contraction of the homeostatic range for any given physiological parameter in response to exposure to sub-toxic, non-damaging, signalling molecules or events, or the removal or cessation of such molecules or events" (Davies, 2016). Adaptive homeostasis enables biological systems to make continuous short-term adjustments for optimal functioning despite ever-changing internal and external environments. Initiation of adaptation in response to an appropriate signal allows organisms to successfully cope with much greater, normally toxic, stresses. These short-term responses are initiated following effective signals, including hypoxia, cold shock, heat shock, oxidative stress, exercise-induced adaptation, caloric restriction, osmotic stress, mechanical stress, immune response, and even emotional stress. There is now substantial literature detailing a decline in adaptive homeostasis that, unfortunately, appears to manifest with ageing, especially in the last third of the lifespan. In this review, we present the hypothesis that one hallmark of the ageing process is a significant decline in adaptive homeostasis capacity. We discuss the mechanistic importance of diminished capacity for short-term (reversible) adaptive responses (both biochemical and signal transduction/gene expression-based) to changing internal and external conditions, for short-term survival and for lifespan and healthspan. Studies of cultured mammalian cells, worms, flies, rodents, simians, apes, and even humans, all indicate declining adaptive homeostasis as a potential contributor to age-dependent senescence, increased risk of disease, and even mortality. Emerging work points to Nrf2-Keap1 signal transduction pathway inhibitors, including Bach1 and c-Myc, both of whose tissue concentrations increase with age, as possible major causes for age-dependent loss of adaptive homeostasis.

Biomarkers in Sleep Apnea and Heart Failure

PURPOSE OF REVIEW

Sleep-disordered breathing (SDB) is highly prevalent in heart failure (HF) and may confer significant stress to the cardiovascular system and increases the risk for future cardiovascular events. The present review will provide updates on the current understanding of the relationship of SDB and common HF biomarkers and the effect of positive airway pressure therapy on these biomarkers, with particular emphasis in patients with coexisting SDB and HF.

RECENT FINDINGS

Prior studies have examined the relationship between HF biomarkers and SDB, and the effect of SDB treatment on these biomarkers, with less data available in the context of coexisting SDB and HF. Overall, however, the association of SDB and circulating biomarkers has been inconsistent. Further research is needed to elucidate the relationship between biomarkers and SDB in HF, to evaluate the clinical utility of biomarkers over standard methods in large, prospective studies and also to assess the impact of treatment of SDB on these biomarkers in HF via interventional studies.

Sleep Disturbances in Patients with Chronic Heart Failure and Their Holistic Consequences—What Different Care Actions can be Implemented?

Background: Sleep disturbances are prevalent among elderly, especially among those with chronic heart failure (CHF) and can affect all dimensions of quality of life (QOL) negatively.

Aim: To describe the most common causes leading to sleep disturbances in patients with CHF, their consequences from a holistic perspective and different care actions that can be implemented.

Methods: MEDLINE and CINAHL databases were searched from 1989 to July 2004.

Findings: Sleep disordered breathing (SDB), and insomnia were the most common causes for sleep disturbances and occurs in 45–82% (SDB) and one-third (insomnia) of all patients with CHF. SDB cause a disturbed sleep structure with frequent awakenings, as well as several adverse effects on the cardiovascular system causing increased morbidity and mortality. Insomnia, caused by anxiety, an unknown life situation in relation to the debut of CHF, or symptoms/deteriorations of CHF can lead to negative effects on all aspects of QOL, as well as daytime sleepiness.

Conclusion: The high prevalence of sleep disturbances and their holistic consequences should be taken into account when nurses asses and plan the care for patients with CHF. Randomized studies with large sample sizes evaluating non-pharmacological nursing interventions that improve sleep are needed.

Sleep, death, and the heart

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.

Chemoreflex physiology and implications for sleep apnoea: insights from studies in humans

NEW FINDINGS

What is the topic of this review? This review summarizes chemoreflex physiology in health and disease, with specific focus on chemoreflex-mediated pathophysiology in obstructive and central sleep apnoea. What advances does it highlight? Chemoreflex mechanisms are thought to contribute significantly to the pathophysiology and adverse outcomes seen in sleep apnoea. Clinical implications of altered chemoreflex function in sleep apnoea from recent studies in humans, including cardiac arrhythmias, coronary artery disease, systolic/diastolic heart failure and sudden cardiac death are highlighted. Activation of the chemoreflex in response to hypoxaemia results in an increase in sympathetic neural outflow. This process is predominantly mediated by the peripheral chemoreceptors in the carotid bodies and is potentiated by the absence of the sympatho-inhibitory influence of ventilation during apnoea, as is seen in patients with sleep apnoea. In these patients, repetitive nocturnal hypoxaemia and apnoea elicit sympathetic activation, which may persist into wakefulness and is thought to contribute to the development of systemic hypertension and cardiac and vascular dysfunction. Chemoreflex activation could possibly lead to adverse cardiovascular outcomes, such as nocturnal myocardial infarction, systolic and/or diastolic heart failure, cardiac arrhythmias and sudden death in patients with sleep apnoea. This review summarizes chemoreflex physiology in health and disease, with specific focus on chemoreflex-mediated pathophysiology in obstructive and central sleep apnoea. Measurement of the chemoreflex response may serve as a potential avenue for individualized screening for cardiovascular disease. Whether modulation of this response in sleep apnoea may aid in the prevention and treatment of adverse cardiovascular consequences will require further study.

Chemohypersensitivity and autonomic modulation of venous capacitance in the pathophysiology of acute decompensated heart failure

Heart failure is increasing in prevalence around the world, with hospitalization and re-hospitalization as a result of acute decompensated heart failure (ADHF) presenting a huge social and economic burden. The mechanism for this decompensation is not clear. Whilst in some cases it is due to volume expansion, over half of patients with an acute admission for ADHF did not experience an increase in total body weight. This calls into question the current treatment strategy of targeting salt and water retention in ADHF. An alternative hypothesis proposed by Fallick et al. is that an endogenous fluid shift from the splanchnic bed is implicated in ADHF, rather than an exogenous fluid gain. The hypothesis states further that this shift is triggered by an increase in sympathetic tone causing vasoconstriction in the splanchnic bed, a mechanism that can translocate blood rapidly into the effective circulating volume, generating the raised venous pressure and congestion seen in ADHF. This hypothesis encourages a new clinical paradigm which focuses on the underlying mechanisms of congestion, and highlights the importance of fluid redistribution and neurohormonal activation in its pathophysiology. In this article, we consider the concept that ADHF is attributable to episodic sympathetic hyperactivity, resulting in fluid shifts from the splanchnic bed. Chemosensitivity is a pathologic autonomic mechanism associated with mortality in patients with systolic heart failure. Tonic and episodic activity of the peripheral chemoreceptors may underlie the syndrome of acute decompensation without total body salt and water expansion. We suggest in this manuscript that chemosensitivity in response to intermittent hypoxia, such as experienced in sleep disordered breathing, may explain the intermittent sympathetic hyperactivity underlying renal sodium retention and acute volume redistribution from venous storage sites. This hypothesis provides an alternative structure to guide novel diagnostic and treatment strategies for ADHF.

Association of plasma homocysteine with self-reported sleep apnea is confounded by age: results from the national health and nutrition examination survey 2005-2006

High levels of plasma homocysteine are implicated in the pathogenesis of cardiovascular diseases especially if accompanied by sleep apnea, but a direct pathogenetic link between plasma homocysteine levels and obstructive sleep apnea is debatable. This association can have far-reaching public health implications considering the inverse association between folate and plasma homocysteine. We used data from the 2005-2006 cycle of the National Health and Nutrition Examination Survey (NHANES) to test the hypothesized associations. Of the 4490 subjects included in analysis, 177 reported sleep apnea. Age-standardized and design-effect-corrected prevalence rates were differential across gender, plasma homocysteine, and red cell folate status. Plasma homocysteine was positively correlated with age (r = 0.38, P < 0.0001). Multivariate analyses using sociodemographic and clinical covariates demonstrated that plasma homocysteine levels retained their respective associations with self-reported sleep apnea in all models except when age was included as a covariate. Our results demonstrate that the claimed association of plasma homocysteine with sleep apnea may be confounded by age.

Effects of home-based exercise training for patients with chronic heart failure and sleep apnoea: a randomized comparison of two different programmes

Objective: To evaluate the effects of home-based exercise for patients with chronic heart failure and sleep apnoea and to compare two different training programmes.

Design: A randomized, prospective controlled trial.

Setting: Department of Cardiology, University Hospital, Brazil.

Subjects: Fifty chronic heart failure patients with sleep apnoea were randomized in three groups: Group 1 (aerobic training, n = 18), Group 2 (aerobic with strength training, n = 18), and Group 3 (untrained, n = 14).

Interventions: The training programme for Groups 1 and 2 began with three supervised exercise sessions, after they underwent three months of home-based exercise. Patients were followed by weekly telephone call and were reviewed monthly. Group 3 had the status of physical activity evaluated weekly by interview to make sure they remained untrained.

Main outcome measures: At baseline and after three months: cardiopulmonary exercise testing, isokinetic strength and endurance, Minnesota living with heart failure questionnaire and polysomnography. Adherence was evaluated weekly.

Results: Of the 50 patients enrolled in the study, 45 completed the programme. Clinical events: Group 1 (one death), Group 2 (one myocardial infarction), Group 3 (one death and two strokes). None were training related. Training groups showed improvement in all outcomes evaluated and the adherence was an important factor (Group 1 = 98.5% and Group 2 = 100.2%, P = 0.743). Untrained Group 3 demonstrated significant decrease or no change on measurements after three months without training.

Conclusion: Home-based exercise training is an important therapeutic strategy in chronic heart failure patients with sleep apnoea, and strength training resulted in a higher increase in muscle strength and endurance.

Time delay in physiological systems: analyzing and modeling its impact

This article examines the functional and clinical impact of time delays that arise in human physiological systems, especially control systems. An overview of the mathematical and physiological contexts for considering time delays will be illustrated, from the system level to cell level, by examining models that incorporate time delays. This examination will highlight how such delays in combination with other system structures and parameters influence system dynamics. Model analysis that reveals the influence of delays can also reveal related physiological effects which may have medical consequences and clinical applications.

Modeling cardio-respiratory system response to inhaled CO2 in patients with congestive heart failure

In this paper we examine a cardiovascular-respiratory model of mid-level complexity designed to predict the dynamics of end-tidal carbon dioxide (CO(2)) and cerebral blood flow velocity in response to a CO(2) challenge. Respiratory problems often emerge as heart function diminishes in congestive heart failure patients. To assess system function, various tests can be performed including inhalation of a higher than normal CO(2) level. CO(2) is a key quantity firstly because any perturbation in system CO(2) quickly influences ventilation (oxygen perturbations need to be more severe). Secondly, the CO(2) response gain has been associated with respiratory system control instability. Thirdly, CO(2) in a short time impacts the degree of cerebral vascular constriction, allowing for the assessment of cerebral vasculature function. The presented model can be used to study key system characteristics including cerebral vessel CO(2) reactivity and ventilatory feedback factors influencing ventilatory stability in patients with congestive heart failure. Accurate modeling of the dynamics of system response to CO(2) challenge, in conjunction with robust parameter identification of key system parameters, can help in assessing patient system status.

Insomnia symptoms and daytime function in stable heart failure

OBJECTIVES

To evaluate insomnia symptoms and the extent to which they are associated with clinical and demographic patient characteristics, daytime symptoms, and functional performance in patients with stable heart failure (HF).

DESIGN

Cross-sectional, observational.

SETTING

Five structured HF disease management programs in the Northeastern U.S.

PARTICIPANTS

173 stable chronic HF patients

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Full polysomnography was obtained for one night in participants' homes. Participants completed the six-minute walk test, Medical Outcomes Study SF-36, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Multi-Dimensional Assessment of Fatigue Scale, Centers for the Epidemiological Studies of Depression Scale, and questionnaire items eliciting insomnia symptoms (self-reported difficulty initiating and maintaining sleep and waking too early in the morning). Over half of HF patients reported insomnia symptoms. These were associated with increased daytime symptoms (depression, fatigue), excessive daytime sleepiness, and functional performance in models that statistically controlled for clinical and demographic covariates. These relationships were not explained by sleep disordered breathing.

CONCLUSIONS

Insomnia symptoms are common in patients with stable heart failure and are associated with daytime symptoms and decrements in functional performance.

Sleep disordered breathing, daytime symptoms, and functional performance in stable heart failure

STUDY OBJECTIVES

To evaluate characteristics of sleep disordered breathing (SDB); clinical and demographic correlates of SDB; and the extent to which SDB explains functional performance and symptoms in stable heart failure patients receiving care in structured HF disease management programs.

DESIGN

Cross-sectional, observational study.

SETTING

Structured heart failure disease management programs.

PARTICIPANTS

170 stable chronic heart failure patients (mean age = 60.3 +/- 16.8 years; n = 60 [35%] female; n = 50 [29%] African American; left ventricular ejection fraction mean = 32 +/- 14.6).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Full polysomnography was obtained for one night on participants in their homes. Participants completed the 6-minute walk, 3 days of actigraphy, MOS-SF 36, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Multi-Dimensional Assessment of Fatigue Scale, and the Centers for the Epidemiological Studies of Depression Scale. Fifty-one percent had significant SDB; Sixteen (9%) of the total sample had central sleep apnea. Severe SDB was associated with a 4-fold increase in the likelihood of poor self-reported physical function (OR = 4.15, 95%CI = 1.19-14.57) and CSA was associated with low levels of daytime mobility (OR = 4.09, 95%CI = 1.23-13.62) after controlling for clinical and demographic variables. There were no statistically significant relationships between SDB and daytime symptoms or self-reported sleep, despite poorer objective sleep quality in patients with SDB.

CONCLUSIONS

Severe SDB is associated with poor physical function in patients with stable HF but not with daytime symptoms or self-reported sleep, despite poorer objective sleep quality in patients with SDB.

Upper airway mechanics

This review discusses the pathophysiological aspects of sleep-disordered breathing, with focus on upper airway mechanics in obstructive and central sleep apnoea, Cheyne-Stokes respiration and obesity hypoventilation syndrome. These disorders constitute the end points of a spectrum with distinct yet interrelated mechanisms that lead to substantial pathology, i.e. increased upper airway collapsibility, control of breathing instability, increased work of breathing, disturbed ventilatory system mechanics and neurohormonal changes. Concepts are changing. Although sleep apnoea is considered more and more to be an increased loop gain disorder, the central type of apnoea is now considered as an obstructive event, because it causes pharyngeal narrowing, associated with prolonged expiration. Although a unifying concept for the pathogenesis is lacking, it seems that these patients are in a vicious circle. Knowledge of common patterns of sleep-disordered breathing may help to identify these patients and guide therapy.

Can O2 dysregulation induce premature aging?

Chronic intermittent or episodic hypoxia, as occurs during a number of disease states, can have devastating effects, and prolonged exposure to this hypoxia can result in cell injury or cell death. Indeed, intermittent hypoxia activates a number of signaling pathways that are involved in oxygen sensing, oxidative stress, metabolism, catecholamine biosynthesis, and immune responsiveness. The cumulative effect of these processes over time can undermine cell integrity and lead to a decline in function. Furthermore, the ability to respond adequately to various stressors is hampered, and this is traditionally defined as premature aging or senescence. This review highlights recent advances in our understanding of the cellular and molecular mechanisms that are involved in the response to intermittent hypoxia and the potential interplay among various pathways that may accelerate the aging process.

6-Month CPAP-Treatment in a Young Male Patient with Severe Obstructive Sleep Apnoea Syndrome — A Case Study from the Couple's Perspective

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) is independently associated with an increased risk for hypertension and cardiovascular disease. Continuous positive airway pressure (CPAP) can reduce mortality and morbidity, but low compliance rates are seen.

AIM

To explore and describe the experiences of CPAP-treatment in a young male patient with severe OSAS during a 6-month period from the couple's perspective. METHODS AND THE CASE: A single case study with a phenomenographic approach was employed. Diagnostic procedures of OSAS and initiation of treatment with Auto-CPAP, humidifier and a nasal mask were performed during 4 visits. Conceptions were collected at 4 different occasions during the 6-month period (before, and 2 weeks, 3 months, and 6 months after treatment initiation) by means of interviews with a 33-year old male patient and his female partner.

FINDINGS

Totally 17 different structural aspects were found to fluctuate during the 6-month period in relation to; influence of stressors, social reactions and adaptation to increase compliance.

CONCLUSION

An increased knowledge about the influence of stressors, the social reactions, and the adaptation can help healthcare personnel to identify and better understand concerns of other patients and spouses during different time phases of the initial 6-month period of CPAP-treatment.

Sleep disturbance in people with heart failure: implications for self-care

Heart failure (HF) is associated with high levels of sleep disturbance and sleep disorders, including insomnia, periodic limb movements during sleep, and sleep disordered breathing. Recent studies underscore the importance of disturbances in sleep, a multidimensional biobehavioral phenomenon, to the pathophysiological processes associated with the development of HF, excess morbidity and mortality, and decrements in quality of life and functional performance. Managing disturbed sleep requires specific self-care strategies that must be incorporated into other self-care tasks associated with HF. Decrements in functioning associated with disturbed sleep may also have a negative impact on the self-care capacity and self-care behaviors of people with HF. The purposes of this article are to evaluate the state of the science relative to the nature of sleep disturbance experienced by people with HF and to discuss the implications of sleep, sleep disorders, and sleep-promoting interventions for self-care of people with HF.

Monitoring of ventilation during the early part of cardiopulmonary exercise testing: The first step to detect central sleep apnoea in chronic heart failure

BACKGROUND AND PURPOSE

To evaluate the prediction of nocturnal central sleep apnoea (CSA) syndrome from the presence of periodic breathing (PB) on diurnal monitoring of pre-exercise (cardiopulmonary exercise test [CPX]) parameters. CSA syndrome is commonly found in congestive heart failure (CHF) patients and has several prognostic and therapeutic implications but is frequently undiagnosed. Awake PB pattern is sometimes observed during the CPX cardiopulmonary monitoring period of gas exchanges in CHF patients referred to the stress test laboratory for routine peak VO2 determination.

PATIENTS AND METHODS

Forty-five consecutive ambulatory patients (2 women/43 men; 60.2+/-11.7 years old) with clinically moderate to severe CHF (New York Heart Association [NYHA] class II/III: 22/23; mean+/-standard deviation left ventricular ejection fraction [LVEF]: 30.5+/-6.6%) underwent a classical maximal CPX test including a 2-min period (pre-test) of gas exchange monitoring and nocturnal ambulatory polygraphic monitoring. PB was defined when a cyclical pattern of VE, VO2, VCO2, was visually noted during the pre-exercise period and/or during the first 4 min of the CPX. CSA syndrome was retained as a central apnoea-plus-hypopnea index (cAHI) equal to or more than 10/h. The sleep study scoring procedure was done independently of the knowledge of the CPX results. Sensitivity, specificity and predictive values were calculated and receiver operating characteristic (ROC) curve analysis was constructed.

RESULTS

Peak VO2 reached 16.4+/-5.2 mL kg(-1)min(-1) (55% of the theoretical value adjusted for gender and age). The polygraphy was completed and validated (at least five consecutive hours of sleep) in all cases. CSA syndrome was found in 28 (62%) patients (mean cAHI: 19.3+/-8.6/h). Sensitivity for the prediction of CSA syndrome reached 92.9% (two false-negative patients with a cAHI of nine) and specificity 94.1% with a predictive accuracy of 93.3%. The only false-positive patient suffered a moderate but significant obstructive sleep apnoea syndrome. Using ROC curve analysis, the W value reached 0.99 for the prediction of CSA from the presence of PB. The presence of CSA syndrome, using logistic regression analysis, is associated with a more severe functional status (NYHA: p<0.01, peak VO2: p<0.002), a lower basal and peak end-expiratory CO2 pressure (PETCO2, all p<0.03), a worse LVEF (p<0.01) and age equal to or more than 60 years (p<0.03).

CONCLUSIONS

The observation of PB in the preliminary period of the CPX test in CHF patients appeared highly predictive of the presence of CSA syndrome during sleep and could prompt the use of polygraphic monitoring in severe CHF patients.

Sleep-related breathing disorders in patients with pulmonary hypertension

BACKGROUND

Cheyne-Stokes respiration (CSR) and central sleep apnea (CSA) are common in patients with left-heart failure. We investigated the hypothesis that sleep-disordered breathing is also prevalent in patients with right ventricular dysfunction due to pulmonary hypertension (PH).

METHODS

We studied 38 outpatients (median age, 61 years; quartiles, 51 to 72) with pulmonary arterial hypertension (n = 23) or chronic thromboembolic PH (n = 15). New York Heart Association (NYHA) class was II to IV, and median 6-min walk distance was 481 m (quartiles, 429 to 550). In-laboratory polysomnography (n = 22) and ambulatory cardiorespiratory sleep studies (n = 38) including pulse oximetry were performed. Quality of life and sleepiness by the Epworth sleepiness score were assessed.

RESULTS

The median apnea/hypopnea index was 8 events/h (quartiles, 4 to 19), with 8 central events (quartiles, 4 to 17), and 0 obstructive events (quartiles, 0 to 0.3) per hour. Seventeen patients (45%) had > or = 10 apnea/hypopnea events/h. Comparison of 13 patients with > or = 10 CSR/CSA events/h with 21 patients with < 10 CSR/CSA events/h (excluding 4 patients with > or = 10 obstructive events/h from this analysis) revealed no difference in regard to hemodynamics, NYHA class, and Epworth sleepiness scores. However, patients with > or = 10 CSR/CSA events/h had a reduced quality of life in the physical domains. Ambulatory cardiorespiratory sleep studies accurately predicted > or = 10 apnea/hypopnea events/h during polysomnography in patients who underwent both studies (area under the receiver operating characteristic curve, 0.93; SE +/- 0.06; p = 0.002). The corresponding value for pulse oximetry was 0.63 +/- 0.14 (p = not significant).

CONCLUSIONS

In patients with PH, CSR/CSA is common, but obstructive sleep apnea also occurs. Sleep-related breathing disorders are not associated with excessive sleepiness but affect quality of life. They should be evaluated by polysomnography or cardiorespiratory sleep studies because pulse oximetry may fail to detect significant sleep apnea.

Association of Type D personality to perceived side effects and adherence in CPAP-treated patients with OSAS

Continuous positive airway pressure (CPAP) is the treatment of choice for obstructive sleep apnoea syndrome (OSAS), but side effects are common and long-term adherence low. The Type D (distressed) personality is defined as a combination of negative affectivity and social inhibition. The association of Type D personality with adherence has not been studied in CPAP-treated patients with OSAS. This study aimed to describe the prevalence of Type D personality in OSAS patients with CPAP treatment longer than 6 months and the association with self-reported side effects and adherence. A cross-sectional descriptive design was used. A total of 247 OSAS patients with a mean use of CPAP treatment for 55 months (6-182 months) were included. Data collection was achieved by two questionnaires; the Type D scale 14 (DS14) (Type D personality), SECI (side effects of CPAP), as well as from medical records (clinical variables and objective adherence to CPAP treatment). Type D personality occurred in 30% of the patients with OSAS and significantly (P < 0.05-0.001) increased the perceived frequency and severity of a broad range of side effects. The objective adherence was significantly lower (P < 0.001) for OSAS patients with Type D compared to OSAS patients without Type D, both with regard to a mean use of 4 h per night and 85% of the self-rated sleep time per night. The additional effect of a Type D personality on perceived side effects and adherence to CPAP treatment found in this study could be used by healthcare personnel when evaluating patients waiting for treatment.

Sleep Disturbances in People Living With Heart Failure

Approximately 10% to 70% of people living with chronic heart failure (HF) experience significant sleep disturbances, which have been shown to impair their health-related quality of life and overall functional performance. Research findings, however, report inconsistent conclusions about sleep disturbances and their adverse effects on HF. The purpose of this article is to review several research studies addressing sleep disturbances in patients with HF and to highlight contradictory and inconsistent findings. Further nursing research about the phenomena related to sleep disturbances in people with HF is warranted so that evidence-based assessments and interventions can be tested in the future.

Obstructive sleep apnoea syndrome ? patients' perceptions of their sleep and its effects on their life situation

AIM

This paper reports a descriptive study of how untreated patients with obstructive sleep apnoea syndrome perceived their sleep situation and how the syndrome affected their life situation.

BACKGROUND

Obstructive sleep apnoea syndrome is a prevalent problem independently associated with an increased risk for hypertension, cardiovascular disease, chronic heart failure and mortality. Increased consumption of healthcare resources can often be seen among patients over a long period of time since many have been undiagnosed and untreated.

METHODS

A phenomenographic approach was employed. Data were collected by interviews during 2005 with 20 purposively selected participants with untreated obstructive sleep apnoea syndrome. Findings. Participants described loud snoring, frequent awakenings, dyspnoea, frustration over nocturia, fear of dying during sleep and partners' anxiety about the apnoea, as being night-time effects of obstructive sleep apnoea syndrome. They described dry and sore throats, tiredness and daytime sleepiness, shame about falling asleep and snoring, thoughts about complications and depressed mood as daytime effects. Needs, such as increased alertness, improved ability to concentrate, improved relationship, adequate information as well as effective treatment, were described. Participants tried self-care strategies such as information-seeking about sleep disturbances and treatment, adapted sleeping routines, change of bedroom arrangements, adapted daily schedules, hyperactivity and avoidance of difficult situations.

CONCLUSION

The perceived effects and needs, as well as tried self-care actions by the patients with obstructive sleep apnoea syndrome in this study, could be used to identify and evaluate concerns of other patients with obstructive sleep apnoea syndrome waiting for treatment.

Validation and clinical utility of a simple in-home testing tool for sleep-disordered breathing and arrhythmias in heart failure: results of the Sleep Events, Arrhythmias, and Respiratory Analysis in Congestive Heart Failure (SEARCH) study

Fifty patients with New York Heart Association class III systolic heart failure were enrolled in this prospective multicenter study that compared the diagnostic accuracy of a home-based cardiorespiratory testing system with standard attended polysomnography. Patients underwent at least 2 nights of evaluation and were scored by blinded observers. At diagnostic cutoff points of > or =5, > or =10, and > or =15 events per hour for respiratory disturbance severity, polysomnography demonstrated a sleep-disordered breathing prevalence of 69%, 59%, and 49%, respectively. Compared with polysomnography, the cardiorespiratory testing system demonstrated predictive accuracies of 73%, 73%, and 75%, which improved to 87%, 87%, and 83%, respectively, when analysis of covariance suggested reanalysis omitting one site's data. The system accurately identified both suspected and unsuspected arrhythmias. The device was judged by 80% of patients to be easy or very easy to use, and 74% of patients expressed a preference for the in-home system. Therefore, this system represents a reasonable home testing device in these patients.

Influence of cardiac function and failure on sleep-disordered breathing: evidence for a causative role

Heart failure is an increasingly common public health problem that is strongly linked to both central and obstructive sleep apnea, collectively referred to as sleep-disordered breathing. Much attention has been given to the deleterious effects of sleep-disordered breathing on the failing heart and potential mechanisms by which treatment of sleep-disordered breathing may result in improved cardiac performance and long-term outcomes. However, there is compelling evidence that cardiac dysfunction may contribute to sleep-disordered breathing. Although there is recognized overlap between pathophysiological mechanisms in central sleep apnea and obstructive sleep apnea, data supporting the role of cardiac function are certain forms of central sleep apnea are well established, whereas investigation into the relationship with obstructive sleep apnea is less mature but continues to evolve. This review will examine experimental and observational data that explore possible pathophysiological mechanisms and potential targets for therapy in heart failure and sleep-disordered breathing.

Sleep and medical disorders

Extensive evidence links cardiovascular disease and sleep disordered breathing. OSA has adverse effects on blood pressure, cardiovascular status,and mortality. Effective CPAP therapy can improve blood pressure and cardiac function in patients who have OSA. Patients who have congestive heart failure have a high prevalence of sleep-disordered breathing, with OSA occurring in 30% of such patients and Cheyne-Stokes respiration in 40%.CPAP is the preferred mode of therapy for both types of sleep-disordered breathing in patients who have coexistent congestive heart failure. Nocturnal worsening of asthma is a common manifestation of this disease that indicates increased disease severity. Therapy focuses on judicious use of long-acting bronchodilators, and the presence of OSA should also be considered. COPD is frequently associated with impaired sleep, likely because of chronic dyspnea and sleep-associated hypoxemia. Appropriate therapy again includes long-acting bronchodilators and possibly nocturnal supplemental oxygen. Gastroesophageal reflux during sleep may lead to prolonged episodes of esophageal acid exposure and may be a common sequela of OSA, perhaps triggering nocturnal worsening of asthma. Endstage renal disease and chronic dialysis are commonly associated with a host of troublesome sleep problems,including OSA, RLS, PLMD, and daytime sleepiness.

Cystic fibrosis patients have poor sleep quality despite normal sleep latency and efficiency

STUDY OBJECTIVES

Cystic fibrosis (CF) patients may be predisposed to poor sleep quality due to upper and lower airway abnormalities and impaired gas exchange. Previous sleep investigations of CF patients using single-night polysomnography have reported conflicting results. We hypothesized that sampling sleep for a prolonged period in a patient's normal environment may give a more representative assessment of sleep quality than a single-night polysomnogram, and that impaired sleep quality would correlate with pulmonary disease severity and self-assessed sleep quality.

DESIGN

Using wrist actigraphy, we measured sleep quality in clinically stable CF patients and age-matched control subjects. In addition, each CF patient and control subject completed the following three questionnaires: the Epworth sleepiness scale; the Pittsburgh sleep quality index (PSQI); and the Medical Outcomes Study 36-item short form.

RESULTS

Twenty CF patients and control subjects were enrolled in the study, and were well-matched for age, sex, and body mass index. The mean (+/- SD) FEV(1) for CF patients was 61.0 +/- 20.1% predicted. CF patients and control subjects had similar sleep duration, sleep latency, and sleep efficiency. However, CF patients had higher PSQI scores (6.45 vs 4.55, respectively; p = .04), a higher fragmentation index (FI) [31.72 vs 18.02, respectively; p < 0.001], and less immobile time (88.87 vs 91.89, respectively; p = 0.02). There was a significant correlation of FI with FEV(1) and PSQI scores.

CONCLUSIONS

Stable CF patients have disrupted sleep, and sleep disruption may in part be related to the severity of pulmonary disease. In addition, the PSQI may be useful in detecting CF patients with poor sleep quality.