Continuous positive airway pressure (CPAP) is the leading treatment for obstructive sleep apnoea (OSA), a prevalent disorder of breathing in sleep strongly associated with obesity. OSA has serious adverse health, social and community effects arising from disturbed breathing, loud snoring, poor quality sleep and cardiovascular sequelae. When used appropriately, CPAP treatment is highly effective in normalising breathing and sleep, improving symptoms and lowering adverse event risk. However, patients do not necessarily accept, tolerate or comply with treatment, with many factors influencing CPAP uptake and longer term use. Although knowledge to address challenges affecting CPAP adherence and CPAP mask and machine technologies continue to improve incrementally, optimising CPAP treatment adherence is an ongoing challenge in sleep medicine.
positive airway pressure (CPAP) with fixed mask pressure is the current
standard treatment for obstructive sleep apnoea (OSA). Auto-CPAP
devices apply at any time the minimally required pressure to normalise
breathing and may improve patient comfort and compliance. We present an
open descriptive study of auto-CPAP treatment at home in patients
previously managed with conventional CPAP.
patients with obstructive sleep apnoea (OSA), previously treated for at
least one year with standard CPAP, were followed prospectively for a
two month period on auto-CPAP. Outcome measures were both subjective
evaluation by the patients and objective (polysomnographic) data
obtained at one and two months of follow up.
sleepiness score did not change significantly between baseline and
follow up after one and two months and no systematic changes in CPAP
related side effects were reported. Compared with the baseline
polysomnographic values without treatment, a significant improvement in
both respiratory and sleep parameters was observed during auto-CPAP.
These results were not significantly different from those obtained with
standard CPAP. A significant correlation was found between the
effective CPAP pressure (Peff) and the amount of time spent below Peff
during auto-CPAP treatment (r = 0.6,p = 0.01).
auto-CPAP treatment in these patients with severe OSA appears to
provide comparable efficacy to that of standard CPAP treatment.
Positive airway pressure (PAP) is the therapy of choice for most sleep-related breathing disorders (SRBD). A variety of PAP devices using positive airway pressure (CPAP, BiPAP, APAP, ASV) must be carefully considered before application. This overview aims to provide criteria for choosing the optimal PAP device according to severity and type of sleep-related breathing disorder. In addition, the range of therapeutic applications, constraints and side effects as well as alternative methods to PAP will be discussed. This review is based on an analysis of current literature and clinical experience. The data is presented from an ENT-sleep-laboratory perspective and is designed to help the ENT practitioner initiate treatment and provide support. Different titration methods, current devices and possible applications will be described. In addition to constant pressure devices (CPAP), most commonly used for symptomatic obstructive sleep apnoea (OSA) without complicating conditions, BiPAP models will be introduced. These allow two different positive pressure settings and are thus especially suitable for patients with cardiopulmonary diseases or patients with pressure intolerance, increasing compliance in this subgroup considerably. Compliance can also be increased in patients during first night of therapy, patients with highly variable pressure demands or position-dependent OSA, by using self-regulating Auto-adjust PAP devices (Automatic positive airway pressure, APAP). Patients with Cheyne-Stokes breathing, a subtype of central sleep apnoea, benefit from adaptive servo-ventilation (ASV), which analyzes breathing patterns continually and adjusts the actual ventilation pressure accordingly. This not only reduces daytime sleepiness, but can also influence heart disease positively. Therapy with positive airway pressure is very effective in eliminating obstruction-related sleep diseases and symptoms. However, because therapy is generally applied for life, the optimal PAP device must be carefully selected, taking into account side effects that influence compliance.
sleep apnea; CPAP; BiPAP; APAP; indication
BACKGROUND--Continuous positive airway pressure (CPAP) therapy is the treatment of choice for the sleep apnoea/hypopnoea syndrome. Compliance with this relatively obtrusive therapy has not been well studied. METHODS--Usage of CPAP was investigated in 54 patients with sleep apnoea/hypopnoea syndrome (median 36 (range 7-129) apnoeas + hypopnoeas/hour slept) over the first 1-3 months after starting CPAP therapy. In all cases CPAP usage was monitored by hidden time clocks that indicated for how long the machines were switched on--that is, the CPAP run time. In 32 patients the time at which the CPAP mask pressure was at the therapeutic level of CPAP pressure set for that patient--that is, the mask time--was also monitored. In all patients objective daytime sleepiness was assessed by multiple sleep latency before and after CPAP therapy. RESULTS--The mean (SE) nightly CPAP run time was 4.7 (0.4) hours. There was no correlation between run time and severity of the sleep apnoea/hypopnoea syndrome as assessed by apnoea + hypopnoea frequency or multiple sleep latency, and no correlation between CPAP usage and improvement in multiple sleep latency. Thirty two patients in whom mask time was recorded had therapeutic CPAP pressures for 89% (3%) of their CPAP run times. Patients who experienced side effects from CPAP used their CPAP machines significantly less than those who did not. CONCLUSIONS--Patients with sleep apnoea/hypopnoea syndrome used CPAP for less than five hours/night on average with no correlation between severity of sleep apnoea/hypopnoea syndrome and CPAP usage. Patients who complained of side effects used their CPAP therapy less. It is recommended that, as a minimum, CPAP run time should be regularly recorded in all patients receiving CPAP therapy.
machines used in the treatment of obstructive sleep apnoea (OSA) are
designed to vary the treatment pressure automatically in order always
to apply the actually needed pressure. Consequently they should be able
to achieve at least identical therapeutic effects as conventional
constant pressure CPAP with a lower mean treatment pressure. The
present study was designed to evaluate the therapeutic efficacy and the
treatment pressure of an auto-CPAP machine (REM+auto®,
SEFAM) in comparison with a conventional CPAP device.
titration, 16 patients with OSA were allocated to receive conventional
CPAP and auto-CPAP treatment under polysomnographic control in a
randomised order. After each treatment the patients were asked to
assess the therapy using a questionnaire; a vigilance test was also
carried out and subjective daytime sleepiness was evaluated using the
Epworth Sleepiness Scale (ESS).
RESULTS—The mean (SD)
apnoea/hypopnoea index (AHI) during auto-CPAP treatment was comparable
with that during conventional CPAP treatment (4.2 (5.1) versus 3.6 (4.0)). Neither an analysis of sleep architecture nor the arousal index
(7.4 (4.1) versus 7.0 (4.3)) revealed any significant differences.
Daytime sleepiness measured with the ESS was also comparable (5.3 (3.4)
versus 6.5 (4.2)). The vigilance test showed normal values after both
treatments in all patients with no significant differences. The mean
pressure during auto-CPAP treatment (8.1 (2.9) mbar), however, was
significantly higher than that employed in conventional CPAP treatment
(7.6 (2.7) mbar; mean difference 0.5 mbar; 95% CI 0.1 to 0.9 mbar;
was equally as effective as conventional CPAP with respect to
therapeutic efficacy. The aim of reducing the treatment pressure with
auto-CPAP, however, was not achieved.
Previous studies have shown that changes in lung volume influence upper airway size and resistance, particularly in patients with obstructive sleep apnoea (OSA), and that continuous positive airway pressure (CPAP) requirements decrease when the lung volume is increased. We sought to determine the effect of a constant lung volume increase on sleep disordered breathing during non‐REM sleep.
Twelve subjects with OSA were studied during non‐REM sleep in a rigid head‐out shell equipped with a positive/negative pressure attachment for manipulation of extrathoracic pressure. The increase in lung volume due to CPAP (at a therapeutic level) was determined with four magnetometer coils placed on the chest wall and abdomen. CPAP was then stopped and the subjects were studied for 1 hour in three conditions (in random order): (1) no treatment (baseline); (2) at “CPAP lung volume”, with the increased lung volume being reproduced by negative extrathoracic pressure alone (lung volume 1, LV1); and (3) 500 ml above the CPAP lung volume(lung volume 2, LV2).
The mean (SE) apnoea/hypopnoea index (AHI) for baseline, LV1, and LV2, respectively, was 62.3 (10.2), 37.2 (5.0), and 31.2 (6.7) events per hour (p = 0.009); the 3% oxygen desaturation index was 43.0 (10.1), 16.1 (5.4), and 12.3 (5.3) events per hour (p = 0.002); and the mean oxygen saturation was 95.4 (0.3)%, 96.0 (0.2)%, 96.3 (0.3)%, respectively (p = 0.001).
An increase in lung volume causes a substantial decrease in sleep disordered breathing in patients with OSA during non‐REM sleep.
obstructive sleep apnoea; lung volume; continuous positive airway pressure; airflow limitation
Obstructive sleep apnoea syndrome (OSAS) affects an estimated 2–4% of the middle aged population. Meta‐analyses of randomised controlled trials have shown that the severe presentation of the syndrome (apnoea hypopnoea index (AHI) >30/hour) is effectively treated with continuous positive airway pressure (CPAP). Until recently there have been insufficient data to determine whether CPAP improves sleepiness in the larger subgroup with mild to moderate OSAS (AHI 5–30/hour).
A systematic search of Medline and a hand search identified seven randomised controlled trials where CPAP was compared with either a placebo or with conservative management in the treatment of mild to moderate OSAS (AHI 5–30/hour). All trials used the Epworth Sleepiness Scale (ESS), four used the Multiple Sleep Latency Test (MSLT), and three used the Maintenance of Wakefulness Test (MWT) to measure sleepiness.
Meta‐analyses indicated that CPAP significantly reduced subjective daytime sleepiness (ESS) by 1.2 points (95% CI 0.5 to 1.9, p = 0.001), improved objective daytime wakefulness (MWT) by 2.1 minutes (95% CI 0.5 to 3.7, p = 0.011), but did not affect objective daytime sleepiness (MSLT, mean benefit −0.2 minutes, 95% CI −1.0 to 0.6, p = 0.6). The two significant effects were small (effect size <0.30).
CPAP elicits small improvements in subjective sleepiness and objective wakefulness in people with mild to moderate OSAS. However, the effects on sleepiness are of limited clinical significance.
continuous positive airway pressure; obstructive sleep apnoea; meta‐analysis
Sleep‐disordered breathing (SDB) is common after stroke, but it is unclear whether it should be treated.
To conduct a randomised controlled trial of continuous positive airway pressure (CPAP) after stroke.
Patients with stroke with ⩾30 apnoeas and hypopnoeas per hour ((A+H)/h) with predominant obstructive sleep apnoea or hypopnoea were randomised to either CPAP treatment or conservative treatment for 8 weeks. Outcomes were measured blind to treatment allocation at 8 weeks and 6 months after the stroke. The primary outcome was physical function on the Nottingham Extended Activities of Daily Living Scale.
Of 658 patients with stroke screened, only 71 (10.7%) were eligible and consented to a sleep study 14–19 days after stroke. 66 patients completed the sleep study (21 women; mean age 72 years), 33 (50%) had ⩾30 (A+H)/h that were predominantly obstructive. 15 were randomised to CPAP treatment and 15 to conventional treatment. Despite intensive efforts, objective use of CPAP was poor, averaging 1.4 h a night. CPAP treatment resulted in no significant improvements (p>0.1) in the primary outcome or in neurological function or sleepiness, and in poorer health status on some measures.
This trial showed no benefit from CPAP treatment, the relevance of the observed detrimental effects is questionable. Even in our highly selected patients with stroke, use of CPAP was poor. At present, CPAP treatment should be advocated for patients with stroke only if they have symptoms of SDB.
Patients with obstructive sleep apnoea (OSA) commonly have mood symptoms such as depression and anxiety. However, the results of randomized controlled trials on the therapeutic effect of CPAP on mood symptoms have been inconsistent. The present study examined whether 3 weeks of CPAP treatment had specific therapeutic effects on mood symptoms in patients with OSA compared with placebo.
A double-blind, parallel, randomized controlled trial using therapeutic and placebo CPAP was performed in 71 patients newly diagnosed with OSA [apnoea-hypopnoea index (AHI) ≥10]. Mood was assessed by the Center for Epidemiologic Studies-Depression (CES-D) Scale, the Profile of Mood States (POMS) and the Brief Symptom Inventory (BSI) before and after 3 weeks of treatment. AHI was used to assess the severity of apnoea. The two groups were compared using a simple comparison of the changes within each arm and repeated measures analysis of variance.
Fifty-six subjects completed the study: 26 in the CPAP group and 30 in the placebo group. The two groups were well matched at baseline, with no significant differences in demographic, mood and apnoea variables. Both groups had severe apnoea, and mild depression and anxiety at baseline. After 3 weeks of treatment, AHI decreased significantly in the CPAP group. The mean change in AHI was −30.7 [standard deviation (SD) 23.1] in the CPAP group and −5.8 (SD 18.3) in the placebo group (difference between groups P<0.001). However, after 3 weeks of treatment, there were no significant time by treatment effects in relation to mood, as assessed by the CES-D, POMS Depression, POMS Tension, BSI Depression or BSI Anxiety (all P>0.05).
In conclusion, 3 weeks of CPAP treatment did not show a specific therapeutic effect on mood symptoms in patients with OSA.
Obstructive sleep apnoea; CPAP; Mood; Depression; Anxiety; Double-blind placebo-controlled
Heart failure (HF) is a growing health problem which paradoxically results from the advances in the treatment of etiologically related diseases (especially coronary artery disease). HF is commonly accompanied by sleep-disordered breathing (SDB), which may directly exacerbate the clinical manifestations of cardiovascular disease and confers a poorer prognosis. Obstructive sleep apnoea predominates in mild forms while central sleep apnoea in more severe forms of heart failure. Identification of SDB in patients with HF is important, as its effective treatment may result in notable clinical benefits to the patients. Continuous positive airway pressure (CPAP) is the gold standard in the management of SDB. The treatments for central breathing disorders include CPAP, bilevel positive airway pressure (BPAP), and adaptive servoventilation (ASV), with the latter being the most modern method of treatment for the Cheyne-Stokes respiration and involving ventilation support with a variable synchronisation dependent on changes in airflow through the respiratory tract and on the patient's respiratory rate. ASV exerts the most favourable effect on long-term prognosis. In this paper, we review the current state of knowledge on the diagnosis and treatment of SDB with a particular emphasis on the latest methods of treatment.
Exercise limitation is an important issue in patients with chronic obstructive pulmonary disease (COPD), and it often co-exists with obstructive sleep apnoea (overlap syndrome). This study examined the effects of nocturnal continuous positive airway pressure (CPAP) treatment on walking capacity in COPD patients with or without obstructive sleep apnoea.
Forty-four stable moderate-to-severe COPD patients were recruited and completed this study. They all underwent polysomnography, CPAP titration, accommodation, and treatment with adequate pressure. The incremental shuttle walking test was used to measure walking capacity at baseline and after two nights of CPAP treatment. Urinary catecholamine and heart rate variability were measured before and after CPAP treatment.
After two nights of CPAP treatment, the apnoea-hypopnoea index and oxygen desaturation index significantly improved in both overlap syndrome and COPD patients, however these changes were significantly greater in the overlap syndrome than in the COPD group. Sleep architecture and autonomic dysfunction significantly improved in the overlap syndrome group but not in the COPD group. CPAP treatment was associated with an increased walking capacity from baseline from 226.4 ± 95.3 m to 288.6 ± 94.6 m (P < 0.05), and decreased urinary catecholamine levels, pre-exercise heart rate, oxygenation, and Borg scale in the overlap syndrome group. An improvement in the apnoea-hypopnoea index was an independent factor associated with the increase in walking distance (r = 0.564).
Nocturnal CPAP may improve walking capacity in COPD patients with overlap syndrome.
Chronic obstructive pulmonary disease; Obstructive sleep apnoea; Walking capacity; Autonomic dysfunction; Continuous positive airway pressure
The present Canadian position paper contains recommendations for the management by dentists of sleep-disordered breathing in adults with the use of oral appliances (OAs) as a treatment option for snoring and obstructive sleep apnea (OSA). The recommendations are based on literature reviews and expert panel consensus. OAs offer an effective, first-line treatment option for patients with mild to moderate OSA who prefer an OA to continuous positive airway pressure (CPAP) therapy, or for severe OSA patients who cannot tolerate CPAP, are inappropriate candidates for CPAP or who have failed CPAP treatment attempts. The purpose of the present position paper is to guide interdisciplinary teamwork (sleep physicians and sleep dentists) and to clarify the role of each professional in the management of OA therapy. The diagnosis of OSA should always be made by a physician, and OAs should be fitted by a qualified dentist who is trained and experienced in dental sleep medicine. Follow-up assessment by the referring physician and polysomnography or sleep studies are required to verify treatment efficacy. The present article emphasizes the need for a team approach to OA therapy and provides treatment guidelines for dentists trained in dental sleep medicine. Many of the dentists and sleep physicians who contributed to the preparation of the present article are members of the Canadian Sleep Society and the authors reached a consensus based on the current literature.
Bruxism; Dental sleep medicine; Obstructive sleep apnea; Oral appliances; Position paper; Sleep-disordered breathing; Snoring
Obstructive Sleep Apnoea (OSA) is a common disorder in adults. Its hallmark is repetitive episodes of partial or complete obstruction of the upper airway during sleep associated with increasing respiratory efforts. This leads to oxyhaemoglobin desaturation, sleep fragmentation, and daytime symptoms, mainly excessive sleepiness. Accumulating
evidence suggests that intermittent hypoxia and oxyhaemoglobin desaturation may, irrespective of obesity, lead to elevation of serum lipids even in non-dyslipidaemic OSA patients. Continuous Positive Airway Pressure (CPAP) is the treatment of choice for OSA, since it eliminates upper airway collapse during sleep and improves sleep fragmentation, daytime symptoms and quality of life. Moreover, it has been proposed that the amelioration of breathing disturbances during
sleep can improve several markers of the lipid profile, such as total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol as well as apolipoproteins A, B and C. Indeed, some studies have reported improvements in these parameters especially in CPAP adherent patients. However, other studies failed to confirm this beneficial effect. The present article reviews the issue whether CPAP treatment exerts a beneficial effect on lipids.
Continuous positive airway pressure; cholesterol; lipid profile; obstructive sleep apnoea; triglycerides.
BACKGROUND: Continuous positive airway pressure (CPAP) is an effective treatment in patients with moderate and severe sleep apnoea/hypopnoea syndrome (SAHS), but the minimum illness severity at which patients obtain benefit from CPAP is unclear. A study was therefore undertaken to investigate whether CPAP improves symptoms and daytime function in patients with mild SAHS. METHODS: Sixteen consecutively recruited patients with mild SAHS (5.0-14.9 apnoeas + hypopnoeas per hour slept and two or more symptoms of SAHS) participated in a prospective placebo controlled randomised crossover trial to assess the effects of CPAP on symptoms and daytime function. Patients spent four weeks on placebo and four weeks on CPAP, undergoing assessments of sleepiness, symptoms, cognitive performance, and well being on the last day of each treatment. Data from the placebo and CPAP assessments were compared. RESULTS: The mean (SE) objective effective use of CPAP was 2.8 (0.7) hours per night. Significant improvements in symptom score (-1.7 (0.5), p < 0.01), mental flexibility (-14 (5) seconds, p = 0.02), and depression rating (-1.6 (0.8), p = 0.03) on CPAP were observed. However, no significant differences in subjective or objective sleepiness were found. Ten of the 16 patients preferred CPAP and opted to continue with this treatment, although this proportion was non- significant (p > 0.4). The eight patients with best CPAP use showed an additional CPAP related improvement in quality of life (-4.4 (1.8), p = 0.03). Those who complied better with CPAP therapy also had a higher average microarousal frequency (p < 0.01) and apnoea+hypopnoea index (p = 0.02) than the poorer compliers. CONCLUSIONS: The results of this study provide evidence for improvements in symptoms and daytime function for patients with mild SAHS treated with CPAP.
BACKGROUND—Patients with the sleep
apnoea/hypopnoea syndrome (SAHS) report improved sleepiness, cognitive
function, and psychological well being after continuous positive airway
pressure (CPAP) therapy, and it is for these daytime features that CPAP
is usually given. However, few randomised or controlled studies exist
on the effects of CPAP on daytime function.
METHODS—A prospective, randomised, single blind,
placebo controlled, crossover trial of daytime function after CPAP was
conducted in 23 patients with SAHS, all with ⩾15
apnoeas+hypopnoeas/hour and ⩾2 symptoms of SAHS. All patients spent
four weeks on CPAP therapy and four weeks on oral placebo treatment,
following randomisation to treatment order. With ethics committee
approval, patients were told the placebo tablet might improve upper
airway function. Average effective CPAP use was monitored using hidden
time clocks. Assessments of objective and subjective sleepiness,
symptoms, cognitive performance, and psychological well being were
performed on the last day of each treatment and compared.
RESULTS—Objective sleepiness measured by sleep
onset latency on the multiple sleep latency test improved with CPAP
(mean difference from placebo +2.4 min, 95% CI 0.8 to 4.0; p<0.001)
as did subjective sleepiness on the Epworth scale (mean difference -6,
95% CI -3 to -9; p = 0.001). Symptom total score also fell with CPAP
(mean difference -1.6, 95% CI -2.2 to -1.0; p<0.001). No
determinants of these changes with active treatment were identified,
and no significant enhancements to cognitive function or psychosocial well being were found in this small sample.
CONCLUSIONS—These findings provide further
evidence for clinically significant benefits to daytime function from CPAP.
CPAP should be considered the first line of treatment in patients with moderate to severe obstructive sleep apnoea. In our centre in Sydney this generally means patients with more than 20 apnoea/hypopnoeas per hour with repeated dips in oxyhaemoglobin saturation and usually some symptomatology. Despite this first line role of nasal CPAP, recent objective studies question whether earlier enthusiastic reports on adherence to CPAP are correct. The role of technical innovations in new CPAP machines in improving usage remains to be tested. The "drop out" rate from physician selection for a CPAP trial to highly compliant user is certainly more than 50% of patients. What happens to these patients? Data from some studies suggest that surgical treatments are used, at least in the USA, but in all probability many of these patients remain untreated. The challenge in the next decade is either to improve CPAP devices to increase usage in this group or to develop other treatment options. The role of intensive inhospital "acclimatisation" to CPAP also has yet to be objectively tested. It is unclear whether "intelligent" CPAP will make huge inroads in increasing the number of patients who accept CPAP trials, prescriptions, or compliance. It will have minimal impact on patients with mask problems or claustrophobia or those who feel that CPAP is inconvenient. There is a high likelihood that it will reduce technologist workload during CPAP titration studies. "Intelligent" CPAP may help to reduce total overnight mouth leakage and therefore reduce nasal side effects. The current expense of developing such devices will mean that they are unlikely to supersede much cheaper standard "one pressure" CPAP machines in the next few years.
apnoea/hypopnoea syndrome (SAHS) causes snoring, apnoeas, and
restlessness during sleep which partners frequently complain about. A
study was undertaken to determine the impact on partners of SAHS and of
treatment of the patient with continuous positive airway pressure (CPAP).
partners and patients with SAHS booked for CPAP treatment completed in
house and validated questionnaires (Pittsburgh sleep quality index,
Short Form 36 self-reported health status) before the patient started
treatment. Twenty three couples in whom the index SAHS patient had no
driving problems were recruited to a randomised crossover trial with 1 month limbs of CPAP and placebo capsule. At the end of each limb the
partners' sleep was monitored by home polysomnography (PSG) and
questionnaires were completed.
treatment partners frequently reported moderate to severe disturbance
from patient snoring/apnoeas/restlessness and had poor sleep quality
and self-reported health status. In the crossover study (22 completed)
the partners' objective sleep quality did not differ between CPAP and
placebo, but they reported benefit from treatment of the patients with
CPAP in subjective sleep quality (p=0.05) and disturbance to sleep
(p=0.03). The reported change in partners' sleep quality between
pre-study and following CPAP treatment correlated positively with CPAP
use (r=0.5, p=0.01).
of patients with SAHS have poor sleep quality and self-reported health
status but only subjective sleep quality benefits from treatment of the
patient with CPAP.
BACKGROUND--The high prevalence of obstructive sleep apnoea (OSA) in patients with systemic hypertension and of hypertension in patients with OSA suggests a causal link between the two disorders. This study was carried out to determine whether nasal continuous positive airway pressure (CPAP) and weight loss affect daytime hypertension in OSA. METHODS--Sixty hypertensive patients with OSA took part in the study; 33 accepted nasal CPAP and used their machine for 5.7 (0.2) hours per night, and the remaining 27 patients refused nasal CPAP and upper airway surgery so the only therapeutic intervention was a recommendation of weight loss. A significant change in hypertension during follow up was defined as either a change in mean blood pressure of at least 10 mm Hg (or more than 8%) without a change in drug treatment, or a reduction in drug dosage with mean blood pressure within these limits. Weight loss was defined as a body mass index of at least 5% below the baseline value. RESULTS--After 512 (41) days, hypertension had become less severe in seven of 12 patients (58%) treated with weight loss only, in eight of 28 patients (29%) with nasal CPAP only, in two of five patients with nasal CPAP and weight loss, and in one of 15 patients without nasal CPAP or weight loss. Multivariate analysis of variance with the outcome of hypertension at follow up as the dependent variable revealed that only the percentage change in body mass index significantly contributed to the course of hypertension. CONCLUSION--The course of hypertension in OSA is more closely linked to weight loss than to elimination of sleep apnoea by nasal CPAP.
Background: It is unclear whether continuous positive airway pressure (CPAP), the treatment of choice for severe obstructive sleep apnoea (OSA), is effective at improving outcomes in mild OSA.
Methods: To help define the role of humidified CPAP in mild OSA, a randomised crossover study was undertaken of patients with an apnoea hypopnoea index (AHI) of 5–30/hour. Subjective sleepiness, objective wakefulness, mood, reaction time, and quality of life were measured at baseline, after 3 weeks treatment with humidified CPAP and 3 weeks sham CPAP (2 week washout).
Results: Twenty nine of 31 enrolled patients (age 25–67 years, seven women, mean (SD) body mass index 31.5 (6) kg/m2) completed the protocol. Humidified CPAP improved polysomnographic indices of OSA and Epworth Sleepiness Scale (2.4 points (95% CI 0.6 to 4.2)). Objective wakefulness (modified maintenance of wakefulness test) showed a trend towards improvement (5.2 minutes (95% CI –0.6 to 11)). Mood (Hospital Anxiety and Depression Scale), quality of life (SF 36, Functional Outcomes of Sleep Questionnaire), and reaction times (Psychomotor Vigilance Task) were not improved more than sham CPAP. Compliance with humidified and sham CPAP both averaged 4.9 hours/night. Placebo effects were evident in many outcomes and there was no clear treatment preference.
Conclusions: Humidified CPAP improves subjective sleepiness and possibly objective wakefulness but not reaction times, quality of life, or mood. These results do not support the routine use of CPAP in all patients with mild OSA, but offers some support for the trialling of CPAP in those with severe sleepiness.
Quadriplegia is a severe, catastrophic injury that predominantly affects people early in life, resulting in lifelong physical disability. Obstructive sleep apnoea is a direct consequence of quadriplegia and is associated with neurocognitive deficits, sleepiness and reduced quality of life. The usual treatment for sleep apnoea is nasal continuous positive airway pressure (CPAP); however, this is poorly tolerated in quadriplegia. To encourage patients to use this therapy, we have to demonstrate that the benefits outweigh the inconvenience. We therefore propose a prospective, multinational randomized controlled trial of three months of CPAP for obstructive sleep apnoea after acute quadriplegia.
Specialist spinal cord injury centres across Australia, New Zealand, the UK and Canada will recruit medically stable individuals who have sustained a (new) traumatic quadriplegia (complete or incomplete second cervical to first thoracic level lesions). Participants will be screened for obstructive sleep apnoea using full, portable sleep studies. Those with an apnoea hypopnoea index greater than 10 per hour will proceed to an initial three-night trial of CPAP. Those who can tolerate CPAP for at least 4 hours on at least one night of the initial trial will be randomized to either usual care or a 3-month period of auto-titrating CPAP. The primary hypothesis is that nocturnal CPAP will improve neuropsychological functioning more than usual care alone. The secondary hypothesis is that the magnitude of improvement of neuropsychological function will be predicted by the severity of baseline sleepiness measures, sleep fragmentation and sleep apnoea. Neuropsychological tests and full polysomnography will be performed at baseline and 3 months with interim measures of sleepiness and symptoms of autonomic dysfunction measured weekly. Spirometry will be performed monthly. Neuropsychological tests will be administered by blinded assessors. Recruitment commenced in July 2009.
The results of this trial will demonstrate the effect of nocturnal CPAP treatment of obstructive sleep apnoea in acute quadriplegia. If CPAP can improve neurocognitive function after injury, it is likely that rehabilitation and subsequent community participation will be substantially improved for this group of predominantly young and severely physically disabled people.
Australian New Zealand Clinical Trial Registry
Patients with mild to moderate obstructive sleep apnoea (OSA) may be managed with different treatment options. This study compared the effectiveness of three commonly used non‐surgical treatment modalities.
Subjects with mild to moderate OSA were randomised to one of three treatment groups for 10 weeks: conservative measures (sleep hygiene) only, continuous positive airways pressure (CPAP) in addition to conservative measures or an oral appliance in addition to conservative measures. All overweight subjects were referred to a weight‐reduction class. OSA was assessed by polysomnography. Blood pressure was recorded in the morning and evening in the sleep laboratory. Daytime sleepiness was assessed with the Epworth Sleepiness Scale. Health‐related quality of life (HRQOL) was assessed with the 36‐Item Short‐Form Health Survey (SF‐36) and Sleep Apnoea Quality of Life Index (SAQLI).
101 subjects with a mean (SEM) apnoea–hypopnoea index (AHI) of 21.4 (1.1) were randomised to one of the three groups. The severity of sleep‐disordered breathing was decreased in the CPAP and oral appliance groups compared with the conservative measures group, and the CPAP group was significantly better than the oral appliance group. Relief from sleepiness was significantly better in the CPAP group. CPAP was also better than the oral appliance or conservative measures in improving the “bodily pain” domain, and better than conservative measures in improving the “physical function” domain of SF‐36. Both CPAP and the oral appliance were more effective than conservative measures in improving the SAQLI, although no difference was detected between the CPAP and oral appliance groups. CPAP and the oral appliance significantly lowered the morning diastolic blood pressure compared with baseline values, but there was no difference in the changes in blood pressure between the groups. There was also a linear relationship between the changes in AHI and body weight.
CPAP produced the best improvement in terms of physiological, symptomatic and HRQOL measures, while the oral appliance was slightly less effective. Weight loss, if achieved, resulted in an improvement in sleep parameters, but weight control alone was not uniformly effective.
Background: Obstructive sleep apnoea (OSA) elicits a number of cardiovascular perturbations that could lead acutely or chronically to increased ventricular ectopy in patients with heart failure (HF). We tested the hypothesis that treatment of OSA with continuous positive airway pressure (CPAP) in patients with HF would reduce the frequency of ventricular premature beats (VPBs) during sleep in association with reduced sympathetic nervous system activity.
Methods: Following optimisation of medical treatment, 18 HF patients with OSA and >10 VPBs per hour of sleep were randomised to a control group (n = 8) or a treatment group who received CPAP (n = 10). The frequency of VPBs and urinary norepinephrine (noradrenaline) concentrations during total sleep time were determined at baseline and after 1 month.
Results: Control patients did not experience any significant changes in apnoea-hypopnoea index (AHI), mean nocturnal O2 saturation, or the frequency of VPBs. In contrast, there was a significant reduction in AHI (p<0.001), an increase in minimum O2 saturation (p = 0.05), a reduction in urinary norepinephrine concentrations (p = 0.009), and a 58% reduction in the frequency of VPBs during total sleep (from mean (SE) 170 (65) to 70 (28) per hour, p = 0.011) after 1 month of CPAP treatment.
Conclusions: In patients with HF, treatment of co-existing OSA by CPAP reduces the frequency of VPBs during sleep. These data suggest that reductions in VPBs and other ventricular arrhythmias through treatment of OSA might improve the prognosis in patients with HF.
Complex sleep apnea syndrome (CompSAS) is a distinct form of sleep-disordered breathing characterized as central sleep apnea (CSA), and presents in obstructive sleep apnea (OSA) patients during initial treatment with a continuous positive airway pressure (CPAP) device. The mechanisms of why CompSAS occurs are not well understood, though we have a high loop gain theory that may help to explain it. It is still controversial regarding the prevalence and the clinical significance of CompSAS. Patients with CompSAS have clinical features similar to OSA, but they do exhibit breathing patterns like CSA. In most CompSAS cases, CSA events during initial CPAP titration are transient and they may disappear after continued CPAP use for 4~8 weeks or even longer. However, the poor initial experience of CompSAS patients with CPAP may not be avoided, and nonadherence with continued therapy may often result. Treatment options like adaptive servo-ventilation are available now that may rapidly resolve the disorder and relieve the symptoms of this disease with the potential of increasing early adherence to therapy. But these approaches are associated with more expensive and complicated devices. In this review, the definition, potential plausible mechanisms, clinical characteristics, and treatment approaches of CompSAS will be summarized.
complex sleep apnea syndrome; obstructive sleep apnea; central sleep apnea; apnea threshold; continuous positive airway pressure; adaptive servo-ventilation
Obstructive sleep apnoea (OSA) has been reported as a predictor of left ventricle (LV) diastolic dysfunction and left atrium (LA) remodelling. The aim of this study is to evaluate the impact of OSA treatment with a continuous positive airway pressure device (CPAP) on the LA volume and function, as well as on the LV diastolic function.
In total, 56 OSA patients were studied. All patients underwent real-time three-dimensional (RT3DE) and two-dimensional echocardiogram with tissue Doppler evaluation in order to estimate LA volumes, function and LV diastolic performance. A total of 30 patients with an apnoea-hypopnoea index greater than 20 were randomly selected to receive sham CPAP (n = 15) or effective CPAP (n = 15) for 24 weeks. They underwent echo examination on three different occasions: at baseline, after 12 weeks and 24 weeks of CPAP or sham CPAP.
In the effective CPAP group we observed the following changes from the baseline to the 24-week echo evaluation: (a) a reduction in the E/E′ ratio (10.3 (1.9) to 7.9 (1.3), p = 0.03); (b) an increase in the LA passive emptying fraction (28.8% (11.9%) to 46.8% (9.3%), p = 0.01); and (c) a reduction in the LA active emptying fraction (42.7% (11.5%) to 25.7 (15.7), p<0.01). In the sham group, there were no changes from the baseline to the 24-week echo. We found a positive correlation between 24 week/baseline LA active emptying volume and 24 week/baseline E/E′ ratios (r = 0.40, p<0.05) and a negative correlation between 24 week/baseline LA passive emptying volume and 24 week/baseline E/E′ ratios (r = −0.53, p<0.05). No significant changes were found on LA total emptying fraction.
CPAP improved LV diastolic function and LA passive emptying, but not LA structural variables in OSA patients.
Trial registration number:
Background: Obstructive Sleep Apnoea Syndrome (OSAS) is a condition of obstruction, apneas and arousals while sleeping. It has been suggested that OSAS independently influences glucose metabolism. The main treatment for OSAS is continuous positive airways pressure (CPAP).
Objectives: To assess the effects of CPAP on insulin resistance and glucose metabolism.
Search strategy: We searched Medline, Embase and the Cochrane Controlled Trial Register (January 2010).
Selection criteria: We included randomised and non-randomised trials comparing CPAP with inactive control or placebo CPAP in adults with OSAS.
Data collection and analysis: Two authors independently assessed trial quality and extracted data. Parallel and crossover group trials were analysed separately. A meta-analysis was carried out.
Results: Three parallel group and two cross-over randomised trials and one controlled trial were included investigating 296 participants. Sample sizes ranged from n=13 to n=102 participants, age was 18 to 75 years, mean body mass index (BMI) 27.2 kg/m² to 37.1 kg/m², mean apnoe hypopnoe index (AHI) 29.7 to 39.7 events per hour, mean dips >4% in arterial oxygen saturation per hour of sleep 1 to 42.7 events. The studies’ methodological quality varied. Follow-up ranged from 4 to 12 weeks. Various endpoints were investigated. CPAP did neither influence plasma insulin levels nor HOMA-index, adiponectin levels or HbA1c value. One study reported a significant positive effect on the insulin sensitivity index (1.68%/min, 95% CI 0.3 to 3.06).
Conclusion: This systematic review does not support the hypothesis that OSAS independently influences glucose metabolism. Sufficiently powered, long-term randomised controlled trials defining changes of insulin resistance as primary endpoint are needed.
Insulin resistance; continuous positive airway pressure; obstructive sleep apnea; diabetes mellitus type 2; meta-analysis