Anxiety and depressive symptoms on continuous positive airway pressure: long-term adherence in patients with sleep apnea syndrome

BACKGROUND

Obstructive sleep apnea (OSA) is often associated to mood disorders and anxiety symptoms that may influence negatively the treatment approach. However, the relationship between anxiety, depression and adherence to treatment is still unclear. We investigate the presence of anxiety and depressive symptoms in newly diagnosed OSA patients and the link between psychological symptoms and acceptance or adherence to CPAP after one year.

METHODS

A validated Italian questionnaire for anxiety and depressive symptoms was administered to 249 patients (69F) with a mean age of 57.2±12.2 and a mean AHI of 40.9±21.9 (ev*hr^-1). The CPAP use in the first and last night of acclimatization and one year after prescription was 6.4±2.2, 6.9±1.4 and 5.3±2.2 hr, respectively.

RESULTS

Anxiety symptoms were reported by 15.6% of patients, depressive symptoms by 6% while 12.5% reported both anxiety and depressive symptoms. Adherence to CPAP in the first night was not adequate in 19.7% of patients with relevant difference between groups: 16.4% in AD^-,20.5% in A⁺,13.3% in D⁺ and 38.7% in AD⁺ (χ²=8.6; P=0.03). However, at the end of acclimatization period only 4.4% of patients utilized CPAP<5/h. One-year after prescription the adherence was adequate in 74.7% of patients without difference between groups. A Cox proportional hazard model demonstrated that AHI (OR=0.985, 95% CI: 0.97-0.99; P=0.03) and compliance to CPAP at the first night of use (OR=0.445; 95% CI: 0.246-0.8; P=0.007) are the only predictive factors of long-term compliance.

CONCLUSIONS

Presence of anxiety and depressive symptoms should be checked before PAP titration since they may negatively influence the early acclimatization and adherence.

Validation Study of Airgo, an Innovative Device to Screen Sleep Respiratory Disorders

Background

Obstructive sleep apnea affects a consistent percentage of the population, and only a minority of patients have been diagnosed and treated because of a discrepancy between resources available for diagnosis and the epidemiology of a disorder possibly affecting nearly one billion people in the world.

Aim

We conducted a study to compare a standard home respiratory monitoring system (Nox T3) with a novel device (Airgo™) consisting of an elastic band and a small recorder, light, comfortable for the patient, and low-cost complete with automatic analysis of the data that produces a screening report indicating the type and severity of sleep respiratory disorder.

Patients and Results

We examined 120 patients, reduced to 118 for technical problems. The mean (SD) age of the patients is 55.7 ± 13 years, their BMI is 27.8 ± 4.3 kg/m2, and their AHI is 22 ± 22 events/h. Patients belong to all the different severity rates of OSA, with a percentage of them classified as free of respiratory disorders. The Airgo™ showed excellent agreement with the results of the gold standard, reporting high levels of sensitivity, specificity, positive and negative predicted value, and accuracy.

Conclusion

Airgo™ is a reliable tool to screen patients with suspected sleep respiratory disorders, well tolerated by the patient based on totally automatic analysis and reporting system, leading to more efficient use of doctor's and clinician's time and resources and extending the opportunity to diagnose more possible candidates for treatment.

Exercise capacity and comorbidities in patients with obstructive sleep apnea

STUDY OBJECTIVES

There are few studies evaluating (1) exercise capacity as assessed by the 6-minute walking distance (6MWD) test in large populations with obstructive sleep apnea (OSA); and (2) correlations with patients' comorbidities.

METHODS

This study presents a cluster analysis performed on the data of 1,228 patients. Severity of exercise limitation was defined on the basis of 6MWD.

RESULTS

Sixty-one percent showed exercise limitation (29.2% and 31.9% mild and severe exercise limitation, respectively). About 60% and 40% of patients were included in cluster 1 (CL1) and 2 (CL2), respectively. CL1 included younger patients with high prevalence of apneas, desaturations, and hypertension with better exercise tolerance. CL2 included older patients, all with chronic obstructive pulmonary disease (COPD), high prevalence of chronic respiratory failure (CRF), fewer apneas but severe mean desaturation, daytime hypoxemia, more severe exercise limitation, and exercise-induced desaturations. Only CRF and COPD significantly (P < .001) correlated with 6MWD < 85% of predicted value. 6MWD correlated positively with apnea-hypopnea index, oxygen desaturation index, nocturnal pulse oxygen saturation (SpO₂), resting arterial oxygen tension, mean SpO₂ on exercise, and negatively with age, body mass index, time spent during night with SpO₂ < 90%, mean nocturnal desaturation, arterial carbon dioxide tension, and number of comorbidities. Patients without severe comorbidities had higher exercise capacity than those with severe comorbidities, (P < .001). Exercise limitation was significantly worse in OSA severity class I when compared to other classes (P < .001).

CONCLUSIONS

A large number of patients with OSA experience exercise limitation. Older age, comorbidities such as COPD and CRF, OSA severity class I, severe mean nocturnal desaturation, and daytime hypoxemia are associated with worse exercise tolerance.

Sleep Breathing Disorders in the COVID-19 Era: Italian Thoracic Society Organizational Models for a Correct Approach to Diagnosis and Treatment

The attenuation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, at least in Italy, allows a gradual resumption of diagnostic and therapeutic activities for sleep respiratory disorders. The knowledge on this new disorder is growing fast, but our experience is still limited and when a physician cannot rely on evidence-based medicine, the experience of his peers can support the decision-making and operational process of reopening sleep laboratories. The aim of this paper is to focus on the safety of patients and operators accessing hospitals and the practice of diagnosing and treating sleep-related respiratory disorders. The whole process requires a careful plan, starting with a triage preceding the access to the facility, to minimize the risk of infection. Preparation of the medical record can be performed through standard questionnaires administered over the phone or by e-mail, including an assessment of the COVID-19 risk. The home sleep test should include single-patient sensors or easy-to-sanitize material. The use of nasal cannulas is discouraged in view of the risk of the virus colonizing the internal reading chamber, since no filter has been tested and certified to be used extensively for coronavirus due to its small size. The adaptation to positive airway pressure (PAP) treatment can also be performed mainly using telemedicine procedures. In the adaptation session, the mask should be new or correctly sanitized and the PAP device, without a humidifier, should be protected by an antibacterial/antiviral filter, then sanitized and reassigned after at least 4 days since SARS-CoV-2 was detected on some surfaces up to 72 h after. Identification of pressure should preferably be performed by telemedicine. The patient should be informed of the risk of spreading the disease in the family environment through droplets and how to reduce this risk. The follow-up phase can again be performed mainly by telemedicine both for problem solving and the collection of data. Public access to hospital should be minimized and granted to patients only. Constant monitoring of institutional communications will help in implementing the necessary recommendations.

Day and Night Control of COPD and Role of Pharmacotherapy: A Review

The topic of 24-hour management of COPD is related to day-to-night symptoms management, specific follow-up and patients’ adherence to therapy. COPD symptoms strongly vary during day and night, being worse in the night and early morning. This variability is not always adequately considered in the trials. Night-time symptoms are predictive of higher mortality and more frequent exacerbations; therefore, they should be a target of therapy. During night-time, in COPD patients the supine position is responsible for a different thoracic physiology; moreover, during some sleep phases the vagal stimulation determines increased bronchial secretions, increased blood flow in the bronchial circulation (enhancing inflammation) and increased airway resistance (broncho-motor tone). Moreover, in COPD patients the circadian rhythm may be impaired. The role of pharmacotherapy in this regard is still poorly investigated. Symptoms can be grossly differentiated according to the different phenotypes of the disease: wheezing recalls asthma, while dyspnea is strongly related to emphysema (dynamic hyperinflation) or obstructive bronchiolitis (secretions). Those symptoms may be different targets of therapy. In this regard, GOLD recommendations for the first time introduced the concept of phenotype distinction suggesting the use of inhaled corticosteroids (ICS) particularly when an asthmatic pattern or eosiophilic inflammations are present, and hypothesized different approaches to target symptoms (ie, dyspnea) or exacerbations. Pharmacotherapy should be evaluated and possibly directed on the basis of circadian variations, for instance, supporting the use of twice-daily rapid-action bronchodilators and evening dose of ICS. Recommendations on day and night symptoms monitoring strategies and choice of the specific drug according to patient’s profile are still not systematically investigated or established. This review is the summary of an advisory board on the topic “24-hour control of COPD and role of pharmacotherapy”, held by five pulmonologists, experts in respiratory pathophysiology, pharmacology and sleep medicine.

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European position paper on drug-induced sleep endoscopy: 2017 Update

BACKGROUND

The first edition of the European position paper (EPP) on drug-induced sleep endoscopy (DISE) was published in 2014 with the aim to standardise the procedure, to provide an in-depth insight into the main aspects of this technique and to have a basis for future research. Since 2014, new studies have been published concerning new sedative agents or new insights into the pattern/levels of the obstruction depending on the depth of sedation. Therefore, an enlarged group of European experts in the field of sleep breathing disorders (SBD), including the most of the first DISE EPP main authors, has decided to publish an update of the European position paper on DISE, in order to include new evidence and to find a common language useful for reporting the findings of this endoscopic evaluation in adult population affected by SBD.

METHODS

The authors have evaluated all the available evidence reported in the literature and have compared experience among various departments in leading European centres in order to provide an update regarding the standardisation of the DISE procedure and an in-depth insight into the main aspects of this technique.

RESULTS

After the first European Position Consensus Meeting on DISE and its update, consensus was confirmed for indications, required preliminary examinations, where to perform DISE, technical equipment required, staffing, local anaesthesia, nasal decongestion, other medications, patient positioning, basics and special diagnostic manoeuvres, drugs and observation windows. So far, no consensus could be reached on a scoring and classification system. However, regarding this aim, the idea of an essential classification, such as VOTE with the possibility of its graded implementation of information and descriptions, seems to be the best way to reach a universal consensus on DISE classification at this stage. A common DISE language is mandatory, and attempts to come to a generally accepted system should be pursued.

Development and validation of the Maugeri Sleep Quality and Distress Inventory (MaSQuDI-17)

Objectives

The aim of this study was to develop and validate a questionnaire designed to measure the impact of sleep impairment on emotional distress in patients with various sleep disorders.

Methods

Five experts created an item data-bank pertaining to sleep-related psychological symptoms and somatic perceptions. Fifty patients in two focus groups examined each item for: a) word clarity (indicating any ambiguity of interpretation) and b) appropriateness for the target population. This process permitted to identify 36 appropriate items. Classical Test Theory and Rasch Analysis were used to further refine the questionnaire, yielding the final 17-item set. Concurrent validation of the new scale was tested with the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and the Anxiety and Depression questionnaires.

Results

Starting from the initial item data-bank, a 17-item questionnaire, the Maugeri Sleep Quality and Distress Inventory (MaSQuDI–17), was produced. Parallel Analysis on the MaSQuDI–17 confirmed the presence of a single dimension; exploratory factor analysis showed salient loading for each item, explaining 58.7% of total variance. Item-remainder correlation ranged from 0.72 to 0.39 and Cronbach alpha was 0.896. Rasch analysis revealed satisfactory psychometric properties of the new scale: the rating structure performed according to expectations, model fit was good and no item dependencies emerged. The scale presented good convergent validity and scores significantly distinguished healthy subjects from OSAS or Insomnia or BSD (p < 0.001).

Conclusions

MaSQuDI –17 shows good psychometric qualities, and can be used to assess the impact of sleep disorders such as Insomnia, OSAS, Central Hypersomnia and BSD on emotional stress.

European position paper on drug-induced sedation endoscopy (DISE)

BACKGROUND

Although drug-induced sedation endoscopy (DISE) represents the most widespread diagnostic tool for upper airway endoscopic evaluation of snoring and obstructive sleep apnea hypopnea syndrome (OSAHS), many controversies exist about how to perform the sedation, the indications for DISE, and how to report DISE findings. The present position paper reports on a consensus as proposed by a group of European experts in the field of DISE after discussion during a recent dedicated meeting.

METHODS

The authors have evaluated all the available evidence reported in the literature and have compared experience among various departments in leading European centers in order to provide a standardization of the DISE procedure and an in-depth insight in the main aspects of this technique.

RESULTS

A proposal of the DISE procedure standardization has been achieved with a general agreement concerning the terminology, indications, contraindications, required preliminary examinations, setting, technical equipment required, staffing, local anesthesia and nasal decongestion, patient positioning, basis and special diagnostic maneuvers, and the applied sedation drugs and observation windows. Otherwise, no consensus has been reached on a scoring and classification system.

CONCLUSIONS

Although consensus has been reached on several aspects of the DISE procedure, some topics remain open to future research, such as a better analysis of the importance of positional aspects during DISE and a further comparison of the differences in degree, level and pattern of upper airway collapse observed during DISE versus during natural sleep and awake endoscopy. Finally, a universally accepted scoring and classification system is lacking.

[Sleep apnea, CPAP therapy and work activity]

Obstructive Sleep Apnea syndrome (OSAS) is largely prevalent among the general adult population, particularly among obese subjects. Diurnal somnolence is a characteristic feature of OSAS, one that can interfere on daily life of the patients and also on his/her work-related activities. Aim of this study was to evaluate the impact of OSAS, its symptoms and its therapy with Continuous Positive Airway Pressure (CPAP) may have on work-related activities. Fourty-eight subjects were studied, all > 18 years old and in a work-related age (< 65 years for men, < 60 years for women). There were 34 males and 14 females, 38 actively working, 3 unemployed, 7 not actively working. Before diagnosis the Epworth Sleepiness Scale (ESS) was 12 +/- 4, after the use of CPAP it was 4 +/- 4 (p< 0.001), the Apnea Hypopnea Index (AHI) before CPAP use was 44 +/- 24, after CPAP use 4 +/- 4 (p< 0.001). CPAP compliance was very good (mean hours of CPAP/night 5 +/- 2). At yearly follow-up, work activity was confirmed in all patients, as all employed patients were still working. Our data seem to indicate that not only OSAS interferes with working performance, mainly due to OSAS-related diurnal somnolence, but also that appropriate CPAP therapy, reinforced with educational activities and followed after one year, is able to ameliorate OSAS-related symptoms, potential cause of inefficiency an occupational risk at work.

Heart rate variability in normal and pathological sleep

Sleep is a physiological process involving different biological systems, from molecular to organ level; its integrity is essential for maintaining health and homeostasis in human beings. Although in the past sleep has been considered a state of quiet, experimental and clinical evidences suggest a noteworthy activation of different biological systems during sleep. A key role is played by the autonomic nervous system (ANS), whose modulation regulates cardiovascular functions during sleep onset and different sleep stages. Therefore, an interest on the evaluation of autonomic cardiovascular control in health and disease is growing by means of linear and non-linear heart rate variability (HRV) analyses. The application of classical tools for ANS analysis, such as HRV during physiological sleep, showed that the rapid eye movement (REM) stage is characterized by a likely sympathetic predominance associated with a vagal withdrawal, while the opposite trend is observed during non-REM sleep. More recently, the use of non-linear tools, such as entropy-derived indices, have provided new insight on the cardiac autonomic regulation, revealing for instance changes in the cardiovascular complexity during REM sleep, supporting the hypothesis of a reduced capability of the cardiovascular system to deal with stress challenges. Interestingly, different HRV tools have been applied to characterize autonomic cardiac control in different pathological conditions, from neurological sleep disorders to sleep disordered breathing (SDB). In summary, linear and non-linear analysis of HRV are reliable approaches to assess changes of autonomic cardiac modulation during sleep both in health and diseases. The use of these tools could provide important information of clinical and prognostic relevance.

General characteristics and risk factors of cardiovascular disease among interstate bus drivers

Workers in the transportation industry are at greater risk of an incorrect diet and sedentary behavior. The aim of our study was to characterize a population of professional bus drivers with regard to clinical and demographic variables, lipid profile, and the presence of cardiovascular risk factors. Data from 659 interstate bus drivers collected retrospectively, including anthropometric characteristics, systolic and diastolic blood pressure, lipid profile, fasting blood glucose, meatoscopy, and audiometry. All participants were male, with a mean age of 41.7 ± 6.9 years, weight of 81.4 ± 3.3 kg, and BMI 27.2 ± 3.3 Kg/m²; the mean abdominal and neck circumferences were 94.4 ± 8.6 cm and 38.9 ± 2.2  cm; 38.2% of the sample was considered hypertensive; mean HDL cholesterol was 47.9 ± 9.5 mg/dL, mean triglyceride level was 146.3 ± 87.9 mg/dL, and fasting glucose was above 100 mg/dL in 249 subjects (39.1%). Drivers exhibited reduced audiometric hearing at 4–8 kHz, being all sensorineural hearing loss. The clinical characterization of a young male population of interstate bus drivers revealed a high frequency of cardiovascular risk factors, as obesity, hypertension, hyperlipidemia, and hyperglycemia, as well as contributing functional characteristics, such as a low-intensity activity, sedentary behavior, long duration in a sitting position, and high-calorie diet, which lead to excessive weight gain and associated comorbidities.

Proposal of a presurgical algorithm for patients affected by obstructive sleep apnea syndrome

PURPOSE

To propose an algorithm for the preoperative management of patients with obstructive sleep apnea syndrome (OSAS) and review the surgical outcomes in such patients.

MATERIALS AND METHODS

This prospective cohort study involved 71 patients with OSAS who underwent presurgical upper airway endoscopy and cephalometry before being assigned to treatment categories based on the site(s) of obstruction, the pattern of collapse, the characteristics of the soft tissue, the air space between the base of the tongue and the posterior wall of the pharynx, and the severity of OSAS. Six months after surgery, they were followed up using polysomnography and the Epworth Sleepiness Scale. The pre- and postsurgical data were compared using a paired Student t test.

RESULTS

The mean preoperative apnea/hypopnea index of the 71 patients (61 male and 10 female) was 40.98 events/hour (range, 14.7 to 87.6 events/hr), and the mean postoperative apnea/hypopnea index was 13.96 events/hour (range, 0 to 20 events/hr). The difference was statistically significant (P < .001).

CONCLUSIONS

This algorithm was developed on the principle that every patient with OSAS should be considered individually. In the authors' opinion, taking into account the number, site(s), pattern, and degree of the collapse/obstruction is a reasonable means of ensuring the correct diagnosis and treatment.

Observational study on efficacy of negative expiratory pressure test proposed as screening for obstructive sleep apnea syndrome among commercial interstate bus drivers--protocol study

Abstract

Trial registration

Registro Brasileiro de Ensaios Clinicos (local acronym RBEC) [Internet]: Rio de Janeiro (RJ): Instituto de Informaçao Cientifica e Tecnologica em Saude (Brazil); 2010 - Identifier RBR-7dq5xx. Cross-sectional study on efficacy of negative expiratory pressure test proposed as screening for obstructive sleep apnea syndrome among commercial interstate bus drivers; 2011 May 31 [7 pages]. Available from http://www.ensaiosclinicos.gov.br/rg/RBR-7dq5xx/.

Sleep disturbances in the critically ill patients: role of delirium and sedative agents

BACKGROUND

Impairment of sleep quality and quantity has been described in critically ill patients. Delirium, an organ dysfunction that affects outcome of the critically ill patients, is characterized by an acute onset of impaired cognitive function, visual hallucinations, delusions, and illusions. These symptoms resemble the hypnagogic hallucinations and wakeful dreams seen in patients with neurological degenerative disorders and suffering of disorders of rapid eye movement (REM) sleep. We assessed the characteristics of sleep disruption in a cohort of surgical critically ill patients examining the hypothesis that severe impairments of rapid eyes movement (REM) sleep are associated to delirium.

METHODS

Surgical patients admitted to the intensive care units of the San G. Battista Hospital (University of Turin) were enrolled. Once weaning was initiated, sleep was recorded for one night utilizing standard polysomnography. Clinical status, laboratory data on admission, co-morbidities and duration of mechanical ventilation were recorded. Patients were a priori classified as having a "severe REM reduction" or "REM reduction" if REM was higher or lower than 6% of the total sleep time (TST), respectively. Occurrence of delirium during intensive care unit (ICU) stay was identified by CAM-ICU twice a day. Multivariate forward stepwise logistic regression analysis was performed with sleep ("severe REM reduction" vs. "REM reduction") as the a priori dependent factor.

RESULTS

REM sleep amounted to 44 (16-72) minutes [11 (8-55) % of the TST] in 14 patients ("REM reduction") and to 2.5 (0-36) minutes [1 (0-6) % of the TST] in the remaining 15 patients ("severe REM reduction") (P = 0.0004). SAPS II on admission was higher in " severely REM deprived" then in "REM deprived" patients. Delirium was present in 11 patients (73.3%) of the patients with "severe REM reduction" and lasted for a median of 3 (0-11) days before sleep assessment, while only one patient having "REM reduction" developed delirium that lasted for 1 day. The factors independently associated with a higher risk of developing "severe REM reduction" were delirium and daily dosage of lorazepam.

CONCLUSION

The present study shows that while all critically ill patients present a profound fragmentation of sleep with a high frequency of arousals and awakenings and a reduction of REM sleep, a percentage of patients present an extremely severe reduction of REM sleep. Delirium and daily dosage of lorazepam are the factors independently associated to extremely severe REM sleep reduction.

Patient-ventilator interaction and sleep in mechanically ventilated patients: Pressure support versus proportional assist ventilation*

OBJECTIVES

To understand the role of patient-ventilator asynchrony in the etiology of sleep disruption and determine whether optimizing patient-ventilator interactions by using proportional assist ventilation improves sleep.

DESIGN

Randomized crossover clinical trial.

SETTING

A tertiary university medical-surgical intensive care unit.

PATIENTS

Thirteen patients during weaning from mechanical ventilation.

INTERVENTIONS

Patients were randomized to receive pressure support ventilation or proportional assist ventilation on the first night and then crossed over to the alternative mode for the second night. Polysomnography and measurement of light, noise, esophageal pressure, airway pressure, and flow were performed from 10 pm to 8 am. Ventilator settings (pressure level during pressure support ventilation and resistive and elastic proportionality factors during proportional assist ventilation) were set to obtain a 50% reduction of the inspiratory work (pressure time product per minute) performed during a spontaneous breathing trial.

MEASUREMENTS AND MAIN RESULTS

Arousals per hour of sleep time during pressure support ventilation were 16 (range 2-74) and 9 (range 1-41) during proportional assist ventilation (p = .02). Overall sleep quality was significantly improved on proportional assist ventilation (p < .05) due to the combined effect of fewer arousals per hour, fewer awakenings per hour (3.5 [0-24] vs. 5.5 [1-24]), and greater rapid eye movement (9% [0-31] vs. 4% [0-23]), and slow wave (3% [0-16] vs. 1% [0-10]) sleep. Tidal volume and minute ventilation were lower on proportional assist ventilation, allowing for a greater increase in Paco2 during the night. Patient-ventilator asynchronies per hour were lower with proportional assist ventilation than with pressure support ventilation (24 +/- 15 vs. 53 +/- 59; p = .02) and correlated with the number of arousals per hour (R = .65, p = .0001).

CONCLUSIONS

Patient ventilator discordance causes sleep disruption. Proportional assist ventilation seems more efficacious than pressure support ventilation in matching ventilatory requirements with ventilator assistance, therefore resulting in fewer patient-ventilator asynchronies and better quality of sleep.

Sleep and exertional periodic breathing in chronic heart failure: prognostic importance and interdependence

BACKGROUND

Sleep and exertional periodic breathing are proverbial in chronic heart failure (CHF), and each alone indicates poor prognosis. Whether these conditions are associated and whether excess risk may be attributed to respiratory disorders in general, rather than specifically during sleep or exercise, is unknown.

METHODS AND RESULTS

We studied 133 CHF patients with left ventricular ejection fraction (LVEF) < or =40%. During 1170+/-631 days of follow-up, 31 patients (23%) died. Nonsurvivors had higher New York Heart Association class, ventilatory response (ve/vco2 slope), and apnea-hypopnea index (AHI) and lower peak vo2 (all P<0.01); lower LVEF and prescription of beta-blockers, and shorter transmitral deceleration time (all P<0.05). Exertional oscillatory ventilation (EOV), established by cyclic fluctuations in minute ventilation that persisted for > or =60% of exercise duration with an amplitude > or =15% of the average resting value, was significantly more frequent in nonsurvivors (42% versus 15%, P<0.01). Multivariable analysis selected AHI (hazard ratio [HR] 5.66, 95% CI 2.3 to 19.9, P<0.01), peak vo2 (HR 0.93, 95% CI 0.90 to 0.97, P<0.01), and beta-blocker prescription (HR 0.34, 95% CI 0.13 to 0.87, P<0.05) as predictors of cardiac events. The best cutoff for AHI was >30/h. EOV was significantly related to AHI >30/h (chi2 14.6, P<0.01): 78% of EOV patients showed AHI >30/h. Multivariable analysis, including breathing disorders alone (EOV, AHI >30/h) or in combination (EOV plus AHI >30/h), selected combined disorders as the strongest predictor of events (HR 6.65, 95% CI 2.6 to 17.1, P<0.01).

CONCLUSIONS

In CHF, EOV is significantly associated with AHI >30/h. Although each breathing disorder alone is linked to total mortality, their combination has a crucial prognostic burden.

The treatment of Sleep Apnea Syndrome: looking for new answers for old problems

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Sleep-related breathing disorders in amyotrophic lateral sclerosis

Sleep-related breathing events in patients with amyotrophic lateral sclerosis (ALS) have been reported in small case series, but the association with the clinical presentation--with (B) or without (nonB) bulbar symptoms--or the relevance for prognosis have not been investigated. We retrospectively analyzed sleep studies of 114 (46 nonB) ALS patients, aged 54 +/- 11 years. Respiratory function was better in nonB patients: forced vital capacity was 76 +/- 20% vs 55 +/- 23% in the bulbar group (p < 0.001); PaCO2 41 +/- 5 vs 44 +/- 6 mm Hg p < 0.05. The mean apnea/hypopnea index (AHI) was higher in nonB patients (22 +/- 12 vs 15 +/- 16 events per hour- p < 0.05); in this group 21 out of 46 patients (46%) had more than 20 events/hour versus 14 out of 68 (21%) in the nonB group (p < 0.005). On the contrary the oxygen desaturation index (ODI) was similar (10 +/- 11 vs 9 +/- 12 events per hour, p = NS). Most events had a central genesis and obstructive events were usually erratic, except in 7 patients (6 in group B) who had more than 10 obstructive events/hour. Data were stratified in three groups: with a disease duration below 1 year (< 1 yr), between 1 and 2 years (1-2 yr), and more than 2 years (> 2 yr). The occurrence of sleep-related respiratory disorders decreased with the increase of disease duration (23 +/- 15; 18 +/- 14; and 16 +/- 15 events per hour respectively), the decrease being significantly lower in the > 2 yr group than in the < 1 yr (p < 0.05). Again ODI was similar in the three groups. In conclusion the present study shows that sleep-related breathing events are more common than previously described in ALS patients, particularly in the first year following onset of the disease. Obstructive events occur rarely, although the prevalence of obstructive sleep apnea is higher than predicted, particularly when bulbar symptoms are present. Patients without bulbar signs show a higher prevalence of central events. The progressive decrease of events with the increase of disease duration could be due to a progressive weakness of respiratory muscles, but it could also suggest an independent role for nocturnal events which could be linked to a worse prognosis or to a more rapid decay of clinical status.

Central sleep apnea in left ventricular dysfunction: prevalence and implications for arrhythmic risk

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 <or=40% without any history of heart failure. Central sleep apnea (CSA), as defined by an apnea-hypopnea index >or=15/h, was present in 26 patients (55%), 17 (36%) of whom had severe CSA (apnea-hypopnea index >or=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 patients without CSA, with mild CSA, and with severe CSA. Heart rate variability was markedly depressed in patients with CSA (P<0.05). Patients with severe CSA also had a higher incidence of nonsustained ventricular tachycardia (P=0.05).

CONCLUSIONS

CSA is highly prevalent in patients with asymptomatic LV dysfunction. The severity of CSA may not be related to the severity of hemodynamic impairment. Severe CSA is associated with impaired cardiac autonomic control and with increased cardiac arrhythmias.

Nocturnal desaturations in COPD: still an open question?

The relevance of sleep oxyhemoglobin desaturations in COPD patients is still a matter of debate. The best definition for clinical outcomes is the occurrence of episodes lasting at least 5 minutes and reaching SaO2 levels less than or equal to 85%. Focusing on longer and milder episodes (at least 30% of the night with SaO2 < 90%) did not provide clinical relevance. One possible consequence of desaturation episodes could be a worsening of pulmonary hemodynamics, but O2 dips could just be a marker of a mechanical derangement associated with a worse prognosis. Data confirming the association of these episodes with the clinical type of COPD and with inflammatory mediator modulation are still lacking.

Sleep disordered breathing and COPD

This issue of Sleep and Breathing presents a section on sleep in COPD, a widespread disease consuming many health resources which is often diagnosed so late that little chance of reversibility remains. The early detection of the warning clinical signs can include sleep studies, mainly in the presence of arterial carbon dioxide levels higher than expected from pulmonary function tests. Two of the articles deal with hypercapnia and nocturnal hypoventilation in COPD; the third underlines the impact of tobacco smoking on snoring and on oxygen availability to tissues, showing a poor reliability of pulse oximetry in subjects with heavy smoking habits.

Blood pressure and heart rate during periodic breathing while asleep at high altitude

The ventilatory and arterial blood pressure (ABP) responses to isocapnic hypoxia during wakefulness progressively increased in normal subjects staying 4 wk at 5,050 m (Insalaco G, Romano S, Salvaggio A, Braghiroli A, Lanfranchi P, Patruno V, Donner CF, and Bonsignore G; J Appl Physiol 80: 1724-1730, 1996). In the same subjects (n = 5, age 28-34 yr) and expedition, nocturnal polysomnography with ABP and heart rate (HR) recordings were obtained during the 1st and 4th week to study the cardiovascular effects of phasic (i.e., periodic breathing-dependent) vs. tonic (i. e., acclimatization-dependent) hypoxia during sleep. Both ABP and HR fluctuated during non-rapid eye movement sleep periodic breathing. None of the subjects exhibited an ABP increase during the ventilatory phases that correlated with the lowest arterial oxygen saturation of the preceding pauses. Despite attenuation of hypoxemia, ABP and HR behaviors during sleep in the 4th wk were similar to those in the 1st wk. Because ABP during periodic breathing in the ventilatory phase increased similarly to the ABP response to progressive hypoxia during wakefulness, ABP variations during ventilatory phases may reflect ABP responsiveness to peripheral chemoreflex sensitivity rather than the absolute value of hypoxemia, suggesting a major tonic effect of hypoxia on cardiorespiratory control at high altitude.

[The assessment of breathing during sleep: a curiosity or clinical necessity?]

The study of sleep, which initially focused on the neurophysiological mechanisms and cardiorespiratory function during the night, has shown the presence of sleep-related breathing disorders that epidemiological, pathophysiological and clinical data have indicated to be associated with increased cardiovascular morbidity and mortality: the obstructive sleep apnea syndrome (OSAS) and the central sleep apnea syndrome (CSAS). OSAS is a condition characterized by repetitive respiratory pauses due to the pharynx wall collapse, with a subsequent obstruction to the airflow. The hemodynamic consequences due to the markedly increased negative intrathoracic pressure (induced by the respiratory muscle effort towards the closed upper airways), the progressive hypercapnic hypoxemia and the arousal terminating the apneas, are the pathophysiological keys of the cardiovascular effects of OSAS and may explain the association between OSAS and the documented increase of cardiovascular morbidity and mortality. CSAS is a breathing disorder characterized by recurrent episodes of central hypopneas or apneas and hyperventilation which, is the classical form described by Cheyne and Stokes, show a crescendo-decrescendo pattern of respiration. Pathophysiological and epidemiological data clearly indicate the link between CSAS and heart failure, also showing a correlation between respiratory disorders and the severity of hemodynamic impairment. However, other mechanisms are involved in the genesis of CSAS in explaining the variable presence of CSAS independent of cardiac function and, more importantly, the impact of CSAS on poor prognosis in heart failure. In conclusion, the data available indicate the need to include screening for sleep-related breathing disorders in the evaluation of cardiac patients who are at risk for OSAS and, particularly, in patients with heart failure, who could really benefit from treatment of the respiratory disorder.

[Sleep disordered breathing: a new risk factor for accidents]

An estimated 2%-4% of the working population could be affected by sleep disordered breathing, in particular by obstructive sleep apnea syndrome. The main symptom is excessive daytime sleepiness, caused by sleep interruptions induced by respiratory events. The level of sleepiness varies according to the severity and duration of the disease: from a slight decrease in vigilance to an almost total inability to keep alert for more than a few hours. In addition, there is an increase in cardiovascular risks and dysmetabolic disorders, which has a variable incidence in the affected population. Even less severe clinical conditions can lead to a reduction in the power of concentration, attention and working performance. The recent trend of research aims at verifying the association between risk factors and obstructive sleep apnea syndrome in order to identify those subjects at real risk, to determine the actual level of sleep-disordered breathing which should be treated and whether the less serious disturbances, so frequent in the general population, represent a real threat to health.

Periodic breathing during sleep in patients affected by fibromyalgia syndrome

Seventeen patients affected by fibromyalgia syndrome (FMS) (16 females and one male) and 17 matched healthy subjects underwent formal polysomnography, a sleep questionnaire and lung function tests. FMS patients slept significantly less efficiently than the healthy controls (p<0.01), had a higher proportion of stage 1 sleep (mean+/-SD, 21+/-6% versus 11+/-4%; p<0.001), less slow wave sleep (p<0.01) and twice as many arousals per hour of sleep (p<0.001). The respiratory pattern of FMS patients showed a high occurrence of periodic breathing (PB) (15+/-8% of total sleep time) in 15/17 patients, versus 2/17 control subjects. The short length of apnoeas and hypopnoeas did not affect the apnoea/hypopnoea index (5.1+/-3.5 versus 3.2+/-1.6; NS), but FMS patients had a greater number of desaturations per hour of sleep (8+/-5 versus 3+/-3; p<0.01). Pulmonary volumes did not differ between the two groups, but FMS patients had a lower transfer factor of the lung for carbon monoxide (TL,CO (5.8+1 versus 7.7+1 mmol x min(-1) x kPa(-1); p=0.001). PB occurrence correlated with TL,CO (r=-0.62; p=0.01), number of desaturations (r=0.76, p=0.001) and carbon dioxide tension in arterial blood (Pa,CO2) (r=-0.50; p=0.05). Stepwise multiple linear regression analysis showed desaturation frequency (p=0.0001) and TL,CO (p=0.029) to be the best predictors of PB percentage (R2 0.73; p=0.0001). Patients complaining of daytime hypersomnolence had a higher number of tender points, about twice as many arousals per hour and a lower sleep efficiency than patients who did not report this symptom. TL,CO was more impaired and the occurrence of PB was higher. The occurrence of periodic breathing in fibromyalgia syndrome patients, which was previously unreported, and is shown to be linked to a reduction of transfer factor of the lung for carbon monoxide could play a major role in the symptoms of poor sleep of these patients.

Prognostic value of nocturnal Cheyne-Stokes respiration in chronic heart failure

BACKGROUND

Nocturnal Cheyne-Stokes respiration (CSR) occurs frequently in patients with chronic heart failure (CHF), and it may be associated with sympathetic activation. The aim of the present study was to evaluate whether CSR could affect prognosis in patients with CHF.

METHODS AND RESULTS

Sixty-two CHF patients with left ventricular ejection fraction </=35%, in NYHA class II to III, underwent clinical evaluation, Doppler echocardiography, ergospirometry, phenylephrine test, Holter recording, and a sleep study to evaluate the occurrence of CSR, expressed as percentage of periodic breathing, and apnea/hypopnea index (AHI) (ie, the number of apneas and hypopneas per hour of recording). During a mean follow-up of 28+/-13 months, 15 patients died of cardiac causes. Nonsurvivors were in a higher NYHA functional class than survivors (P<0.001) and had a more depressed left ventricular ejection fraction (P<0.03), a shorter deceleration time of early filling (P<0. 05), larger left and right atria (P<0.05 and P<0.02, respectively) and a lower peak V(O2) (P<0.05). Nonsurvivors also spent a greater percentage of the night in periodic breathing (P<0.01) with a greater AHI (P<0.03) and showed lower values of diurnal baroreflex sensitivity (P<0.05) and of heart rate variability (sdNN: P<0.01). Multivariate analysis revealed the AHI (chi2, 10.4; P<0.01), followed by left atrial area (chi2, 5.7; P<0.01), as the only independent and additional predictors of subsequent cardiac death. Patients at very high risk for fatal outcome could be identified by an AHI >/=30/h and left atria >/=25 cm2.

CONCLUSIONS

The AHI is a powerful independent predictor of poor prognosis in clinically stable patients with CHF. The presence of an AHI >/=30/h adds prognostic information compared with other clinical, echocardiographic, and autonomic data and identifies patients at very high risk for subsequent cardiac death.

Effects of high-altitude periodic breathing on sleep and arterial oxyhaemoglobin saturation

This study aimed to investigate the effect of periodic breathing (PB) at high altitude on sleep structure and arterial oxygen saturation (Sa,O2). Five healthy subjects underwent polysomnographic studies at sea level, and during the first and the fourth week of sojourn at 5,050 m. Their breathing pattern, sleep architecture and Sa,O2 were analysed. PB was detected in the high-altitude studies during nonrapid eye movement (NREM) sleep and tended to increase from the first to the fourth week. Stages 3-4 were absent in four subjects at the first week, but only in one at the fourth week, irrespective of the amount of PB. The arousal index was 11.6+/-3.8 at sea level, 30.1+/-15.5 at the first week at altitude and 33.0+/-18.2 at the fourth week. At altitude, arousal index in NREM sleep was higher during PB than during regular breathing. In NREM sleep, the mean highest Sa,O2 levels in NREM epochs with PB were higher than in those with regular breathing by 2.8+/-1.7% at the first week and 2.9+/-1.5% at the fourth week (p<0.025). From the first to the fourth week, mean Sa,O2 increased significantly during wakefulness (5.6%), NREM (5.2% with regular breathing and 5.3% with PB) and rapid eye movement sleep (7.6%). The data demonstrate a slight role of periodic breathing in altering sleep architecture at high altitude and also show that periodic breathing induces only a minor improvement in arterial oxygen saturation during nonrapid eye movement sleep.

Pulmonary failure as a cause of death in COPD

Data on the outcome of patients with chronic obstructive pulmonary disease (COPD) are limited. We know that the prognosis is poor when respiratory insufficiency develops, but we have little information on the actual cause of death. Epidemiological studies are suitable for the assessment of the prevalence of the disease, but give no details on the actual cause of death. Age and forced expiratory volume in one second (FEV1) have been recognized as the best predictors of mortality in studies designed to quantify survival of COPD patients, particularly when the post-brochodilator value is used, as this provides a better estimate of airway and parenchymal damage. Data from Intensive Care Units on acute respiratory failure have several significant limitations. Firstly, it is probable that some patients elect not to undergo intensive treatment for a terminal bout of respiratory failure, particularly if it is not first episode. Secondly, the actual cause of death is often not described in adequate detail. Hypoxaemia and acidaemia are the main risk factors in acute exacerbation of the disease and the presence of pulmonary infiltrates on chest radiographs worsens the prognosis. A single bout of respiratory failure appears to have no effect on the prognosis of COPD patients after recovery, but there is a consistent increase in mortality after the second episode. It seems possible to manage the majority of episodes of acute respiratory failure with mechanical ventilation administered with noninvasive techniques. When endotracheal intubation is necessary, the prognosis is usually poor and the survival after 1 yr is usually lower than 40%. The role of long-term home mechanical ventilation is still unclear. Results from pivotal studies have been encouraging, although survival is far less impressive than in neuromuscular disorders. In patients with end-stage lung disease, lung transplantation can be considered the only possibility of increasing pulmonary functional capacity. However the technique is reserved only for a highly selected group of patients and data on the long-term outcome are awaited.

Causes of death in patients with COPD and chronic respiratory failure

Although the factors associated with mortality, such as forced expiratory volume in one second (FEV1), arterial oxygen tension (Pa,O2) and pulmonary arterial pressure, have been well described, there is limited information on the circumstances of death in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the causes and circumstances of death in patients with COPD and chronic respiratory failure (Pa,O2 < 8.0 kPa (60 mmHg) breathing air), treated with long-term oxygen therapy (LTOT). Ten European centres participated in the study and data were collected from patients both during a period of clinical stability and at the time of death. Of the 215 patients evaluated (161 males and 54 females; aged 66 +/- 10 yrs), the major causes of death were: acute on chronic respiratory failure (38%); heart failure (13%); pulmonary infection (11%); pulmonary embolism (10%); cardiac arrhythmia (8%); and lung cancer (7%). Seventy five percent of patients died in hospital. There was no difference in the number of patients who died in the morning, afternoon and night hours. Twenty percent of the total died during sleep and in 26% death was unexpected. A lower arterial carbon dioxide tension (Pa,CO2), less oxygen usage per 24 h, and increased incidence of arrhythmias were seen in those patients who died suddenly. Drug therapy was not related to unexpected death. The majority of patients with chronic obstructive pulmonary disease on long-term oxygen therapy died from chronic or acute on chronic respiratory failure. Prevention and treatment of respiratory failure in patients with chronic obstructive pulmonary disease is likely to have the greatest impact in reducing mortality.

Nocturnal asthma: mechanisms and therapy

Nocturnal worsening of symptoms affects a large number of patients suffering from asthma. Recent studies show that airway inflammation underlies nocturnal awakenings and increased airway hyperreactivity. These studies, however, yield conflicting results concerning the pathogenesis of the disease, making it difficult to understand the mechanisms involved in sustaining nocturnal asthma. This article reviews the principal pathogenetic mechanisms of nocturnal asthma, showing that worsening of symptoms at night may be the result of a more severe disease as well as of increased inflammation at night and higher susceptibility. We also review the pharmacologic treatment of nocturnal asthma which is mainly based on antiinflammatory treatment with inhaled or oral steroids or combined therapies with theophylline and beta 2 agonists. The activity of antileukotrine compounds in asthma is also summarized.

Cardiovascular and ventilatory response to isocapnic hypoxia at sea level and at 5,050 m

To assess the effect of chronic hypoxic conditions on ventilatory, heart rate (HR), and blood pressure (BP) responses to acute progressive isocapnic hypoxia, we studied five healthy Caucasian subjects (3 men and 2 women). Each subject performed one rebreathing test at sea level (SL) and two tests at the Pyramid laboratory at Lobuche, Nepal, at the altitude of 5,050 m, 1 day after arrival (HA1) and after 24 days of sojourn (HA2). The effects of progressive isocapnic hypoxia were tested by using a standard rebreathing technique. BP, electrocardiogram, arterial oxygen saturation, airflow and end-tidal CO2 and O2 were recorded. For each subject, the relationships between arterial oxygen saturation and HR, systolic BP and minute ventilation (VE), respectively, were evaluated. At HA1, the majority of subjects showed a significant increase in VE and BP response and a decrease in HR response to progressive isocapnic hypoxia as compared to SL. At HA2, VE and BP responses further increased, whereas the HR response remained similar to that observed at HA1. A significant relationship between hypoxic ventilatory responses and both systolic and diastolic BP responses to progressive hypoxia was found. No significant correlation was found between hypoxic ventilatory and HR responses.

When is liquid oxygen really needed?

Liquid oxygen is a synonym for portable oxygen, as it combines a big cylinder with an easy-to-fill portable unit, suitable for exercise and use out-doors. The main drawback is its high cost, inherent in a home delivery system, which discouraged many nations from its introduction. The best candidates are patients able to move, who are still active and do not have psychological reticence to its use in public. Transtracheal systems and the advantage of a round the clock treatment and a reduction of flow rate, crucial both to lengthen the autonomy of portable units and to avoid flows higher than 4 L.min-1, which cannot be maintained. Finally, patients on liquid oxygen usually have a better adherence to treatment, mainly compared to those using a concentrator, possibly improving its effectiveness, which is notoriously dependent on total usage per day.

The effects of doxofylline versus theophylline on sleep architecture in COPD patients

Theophylline is known to alter sleep architecture because of its affinity to adenosine receptors. One of the consequences of disrupted sleep is impaired cognitive performance. A single-blind, randomized cross-over study of eight male chronic obstructive pulmonary disease (COPD) patients was undertaken to evaluate the effects of theophylline versus doxofylline on sleep architecture. The patients, who were all ex-smokers, had been treated with theophylline. Mean age was 53 +/- 12 yrs, forced expiratory volume in one second (FEV1) 50 +/- 22% predicted and forced vital capacity (FVC) 70 +/- 18% predicted. Following a wash-out period, four patients were given oral slow-release theophylline (T) (300 mg b.i.d.) for one week, followed by a cross-over to doxofylline (D) (400 mg t.i.d.) for a second week. The other four patients were given the drugs in the reverse order. All patients underwent polysomnography at baseline and at the end of each week of treatment. The number of arousals per hour was 5.5 +/- 2.9 at baseline, 9.4 +/- 5.2 during T treatment and 5.4 +/- 4.4 during D treatment. During T treatment, sleep efficiency was 60 +/- 19% vs 75 +/- 13% recorded at baseline trial and 68 +/- 25 recorded during D treatment. Sleep quality, during T treatment, was poorer than at baseline, with a greater increase in the percentage of wakefulness and more stage 2 sleep than at baseline. Slow wave sleep was reduced with both treatments, particularly D. Neither drug affected the arterial oxygen saturation (Sao2) or respiratory rate during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term oxygen therapy

Controlled studies have demonstrated that the correction of tissue hypoxia increases survival and reduces pulmonary hypertension in patients with chronic obstructive pulmonary disease (COPD) receiving oxygen therapy 15 h/day or longer. Long-term oxygen therapy (LTOT) is recommended to any patient with COPD who has a PaO2 of < or = 7.3 kPa. In most countries, the PaO2 threshold is 8kPa in patients with chronic hypoxemia (PaO2 > or = 55 mm Hg) with associated hematocrit > or = 55%, pulmonary hypertension or cor pulmonale. Desaturations during sleep or exercise should be investigated, although a consensus as to whether and how these episodes should be treated has yet to be reached. The indications for LTOT in restrictive lung diseases, such as interstitial pulmonary fibrosis and pneumoconiosis, remain controversial. In many countries, oxygen is not prescribed if the patient is a current smoker. Breathlessness without hypoxemia should not be considered an indication for LTOT. The oxygen is usually administered through nasal cannula. Venturi type masks, nasopharyngeal and transtracheal catheters are associated with several drawbacks. Oxygen is usually supplied by the relatively cheap oxygen concentrator. Liquid oxygen is favored when a portable source is an important requirement. Many questions remain unanswered concerning the duration of added survival, the effect of LTOT on physiological parameters such as pulmonary artery pressure, respiratory failure in non-COPD patients, exercise and nocturnal desaturations.