Positive airway pressure therapy of OSA

Positive airway pressure is standard therapy for patients with obstructive sleep apnea. It comes in three basic varieties: (1) continuous positive airway pressure (CPAP), (2) bilevel positive airway pressure (BPAP), and (3) autotitrating positive airway pressure (APAP). When properly titrated, positive airway pressure devices minimize the number of sleep-related breathing disorder events, often producing dramatic results. Sleep-related breathing may completely normalize, specific stages of sleep may selectively rebound due to having been chronically suppressed, sleep microstructure may improve, and the patient may awaken feeling refreshed for the first time in years. The specific indications and criteria for recommending APAP, BPAP, and CPAP therapy are reviewed. The titration process is presented in a step-by-step manner and titration grading is explained. Issues surrounding the interface, acceptance, utilization, and side-effects are discussed. Finally, we present an assortment of approaches for troubleshooting clinical problems commonly encountered among patients being treated with positive airway pressure therapy.     

Randomised short-term trial of high-span versus low-span APAP for treating sleep apnoea

Sleep and Breathing - Auto-titrating continuous positive airway pressure (APAP) devices were developed to improve treatment efficacy and compliance in patients with obstructive sleep apnoea...     

Continuous positive airway pressure therapy in sleep apnoea

Sleep apnoea is associated with increased mortality and morbidity. The treatment goal is to reduce the neurocognitive and cardiovascular sequelae. CPAP therapy in sleep apnoea is discussed in two parts in the article. The first part will consider CPAP therapy in the more common form of sleep apnoea (i.e. obstructive or mixed sleep apnoea) and the second part will consider CPAP therapy in central sleep apnoea. Alternative positive airway pressure modalities are discussed. CPAP therapy has been extensively studied and it remains the mainstay of treatment in obstructive sleep apnoea, as it is still the most consistently efficacious and safe option. However, its major disadvantage is that it does not confer a cure to this disorder and hence therapy is generally life long with its usual treatment compliance problems. As such, there are continuous improvement strategies. The role of CPAP therapy in central sleep apnoea is more limited. There has been increasing data on the beneficial effect of CPAP on central sleep apnoea/Cheyne-Stokes respiration in congestive heart failure. Evidence for CPAP therapy in sleep apnoea has evolved significantly over the last decade. However, more research and publication of large-scale long-term randomized trials of treatment in sleep apnoea to assess patient-orientated outcomes and preferences are necessary.     

Auto-titrating continuous positive airway pressure for treating adult patients with sleep apnea syndrome

PURPOSE OF REVIEW: The treatment of sleep apnea syndrome (SAS) is continuous positive airway pressure (CPAP) as the first line of therapy. The current standard is for an attendant technician to titrate CPAP by means of an in-laboratory polysomnography to obtain a fixed single pressure. Over the past decade and a half, some devices able to modify the pressure delivered to the patient overnight and from night to night have become available. The efficacy of such devices to manage SAS has been demonstrated, however the question of their use either as unattended APAP to determine pressures for fixed CPAP or for self-adjusting APAP treatment on a long-term basis is still matter of debate. RECENT FINDINGS: However, if cost considerations may render reluctant to APAP, off note, using APAP could allow initiation of treatment more quickly, reduce in-laboratory time, and reduce healthcare costs. SUMMARY: Auto-titrating continuous positive airway pressure and CPAP are to date equivalent in terms of efficacy to treat SAS, but APAP could allow quick initiation of treatment and therefore reduce healthcare costs.     

Cardiovascular and metabolic effects of CPAP in obese males with OSA.

Obstructive sleep apnoea is associated with increased blood pressure and other features of the metabolic syndrome. The aim of the present study was to determine the relative effectiveness of continuous positive airway pressure (CPAP) in modifying these outcomes. A randomised placebo-controlled blinded crossover trial comparing cardiovascular and metabolic outcomes after 6 weeks of therapeutic and sham CPAP was performed in 34 CPAP-na?ve patients (mean+/-SD body mass and respiratory disturbance indices were 36.1+/-7.6 and 39.7+/-13.8, respectively). Mean waking systolic and diastolic blood pressure fell by 6.7 and 4.9 mmHg, respectively, when compared with sham CPAP. No change was observed in glucose, lipids, insulin resistance or the proportion of patients with metabolic syndrome. In CPAP-compliant patients the fall in blood pressure was greater and the baroreceptor sensitivity improved significantly but no metabolic variable changed. In obese Caucasians with untreated obstructive sleep apnoea, continuous positive airways pressure can improve baroreceptor responsiveness and reduce waking blood pressure within 6 weeks, but this treatment period was insufficient to modify insulin resistance or change the metabolic profile. The mechanisms underlying this difference in the time course of blood pressure and metabolic response to continuous positive airway pressure in obstructive sleep apnoea requires further exploration.     

Importance of sleep stage- and body position-dependence of sleep apnoea in determining benefits to auto-CPAP therapy.

The influence of sleep stage- and body position-dependence of sleep apnoea on treatment efficacy and compliance between conventional continuous positive airway pressure (CPAP) and auto CPAP therapy was evaluated. Thirty-three newly treated sleep apnoea hypopnoea syndrome (SAHS) patients were randomly allocated to conventional or auto-CPAP therapy. Six patients of each treatment group were classified as having sleep stage- and body position-dependent obstructive breathing abnormalities according to the results of the baseline sleep study. After 3 weeks of treatment, the Epworth sleepiness score tended to be higher (p = 0.08) and the ability to stay awake lower (p = 0.02) in patients with dependent breathing abnormalities treated with fixed CPAP, than in the other patients. The effective pressure/time index was significantly lower in sleep stage- and body position-dependent patients treated with fixed CPAP, than in the other patients (p = 0.02). The number of hours the machine was turned on and a positive pressure applied, tended to be smaller in dependent patients treated with fixed CPAP than in independent patients of this treatment group and in patients treated with auto-CPAP. A night-to-night variability index (VI) of positive pressure changes was obtained in the auto-CPAP group. This index significantly decreased with time in the dependent patients while it remained unchanged in the independent group. It is concluded that auto-continuous positive airway pressure may have specific indications in a subset of obstructive sleep apnoea patients with sleep stage- and body position dependent nocturnal breathing abnormalities.     

Automatic pressure titration with APAP is as effective as manual titration with CPAP in patients with obstructive sleep apnea

BACKGROUND: The optimal approach to initiate positive-pressure therapy in patients with obstructive sleep apnea is still debated. Current options are autotitrating positive airway pressure (APAP) or manual titration with continuous positive airway pressure (CPAP). Procedures differ by parameters and by algorithms used for adapting pressure. OBJECTIVES: To evaluate the efficacy of attended automatic titration in a randomized crossover study compared with manual titration over 2 nights where the sequence of the titration mode was changed. Therapy outcome was controlled after 6 weeks. METHODS: 21 sleep apnea patients were treated using manual CPAP versus automatic APAP titration. The mode used during the 2nd night was continued for 6 weeks. Cardiorespiratory polysomnography, Epworth Sleepiness Scale (ESS), SF-36 score and compliance were assessed. RESULTS: Apnea-hypopnea index reduction was equally effective at similar effective pressure independent of the titration mode. If APAP was applied during the 1st night, total sleep time was longer (384 vs. 331 min, p < 0.01) and sleep efficacy was higher (91 vs. 81%, p < 0.01) than after starting with manual titration with CPAP. Compliance was comparable in both groups (4.6 +/- 1.9 h). The ESS improved in both groups (from 12.9 to 6.5). SF-36 scores and therapeutic pressure did not much change. CONCLUSIONS: Taking the sequence of titration into account, we found equal effectiveness of CPAP and APAP. Sleep quality was better with initial application of APAP - which favors attended automatic titration if only 1 titration night is possible. Both modes are comparable after 6 weeks regarding therapeutic pressure, efficacy, compliance and quality of life.     

Randomized short-term trial of two autoCPAP devices versus fixed continuous positive airway pressure for the treatment of sleep apnea

We evaluated the efficacy of two different continuous positive airway pressure devices with automatic mask pressure adjustment (autoCPAP) in comparison with fixed CPAP in treating obstructive sleep apnea syndrome in 29 patients. The mean (+/- SE) apnea-hypopnea index was 46 +/- 4 per hour and the Epworth score was 14.2 +/- 0.7. Patients were treated over three consecutive 1-month periods with three regimens in random order: an autoCPAP device responding to apnea-hypopnea and snoring, another autoCPAP device responding to snoring and changes in flow contour, and fixed CPAP at the 90th pressure percentile titrated by autoCPAP over 2 weeks. Allowed pressure in the autoCPAP mode was 4 to 15 cm H2O. At the end of each treatment period, symptoms, quality of life, vigilance, and nocturnal breathing disturbances were evaluated. All three treatment modalities improved symptoms, quality-of-life domains, and apnea-hypopnea index significantly and to a similar degree. Mean (+/- SE) maintenance-of-wakefulness time increased by 4.5 +/- 1.8, 6.0 +/- 1.5, and 6.1 +/- 1.4 minutes with DeVilbiss AutoAdjust LT, AutoSet T, and fixed-pressure CPAP, respectively (p<0.001 vs. baseline, p=not significant for comparisons among the three modalities). We conclude that both autoCPAP devices were equally effective as fixed-pressure CPAP in improving major outcomes during short-term therapy of sleep apnea.     

Proportional positive airway pressure: a new concept to treat obstructive sleep apnoea.

Proportional positive airway pressure (PPAP) was designed to optimize airway pressure for the therapy of obstructive sleep apnoea (OSA). In a randomized crossover prospective study, the clinical feasibility of PPAP and its immediate effects on the breathing disorder and sleep in comparison with continuous positive airway pressure (CPAP) was evaluated. Twelve patients requiring CPAP therapy underwent CPAP and PPAP titration in a random order. Obstructive and mixed respiratory events could be completely abolished with both forms of treatment. This efficacy could be achieved at a significantly lower mean mask pressure during PPAP titration (8.45+/-2.42 cmH2O) compared to CPAP (9.96+/-2.7 cmH2O) (p=0.002). The mean minimal arterial oxygen saturation (Sa,O2) (82.8+/-6.5%) on the diagnostic night increased significantly (p<0.001) to an average Sa,O2 of 93.35+/-1.71% and 93.19+/-2.9% during CPAP and PPAP titration. Total sleep time, slow wave sleep and rapid eye movement (REM) sleep increased significantly by the same amount during both CPAP and PPAP titration (p<0.001), while sleep stage nonrapid eye movement (NREM) 1 and 2 decreased. Six patients preferred the PPAP titration night, four patients did not have a preference, and two patients preferred CPAP. The present data show that proportional positive airway pressure is as effective as continuous positive airway pressure in eliminating obstructive events and has the same immediate effect on sleep. The lower average mask pressure during proportional positive airway pressure implies potential advantages compared to continuous positive airway pressure. Proportional positive airway pressure presents a new effective therapeutic approach to obstructive sleep apnoea.     

A randomized trial of auto-titrating CPAP and fixed CPAP in the treatment of obstructive sleep apnea-hypopnea

BACKGROUND: Continuous positive airway pressure (CPAP) remains the treatment of choice for obstructive sleep apnea hypopnea (OSAH). Auto-titrating CPAP (APAP) devices automatically adjust pressure and may improve treatment compliance compared to fixed CPAP (F-CPAP). METHODS: Randomized, prospective, single-blind, crossover trial to compare efficacy, side effects, compliance, patient satisfaction and preference between APAP and F-CPAP therapy in patients with moderate to severe OSAH. There were two treatment periods of 4 weeks each (APAP and F-CPAP), separated by a 2-week washout period. RESULTS: Ten CPAP-naive OSAH patients (9 males) completed the study. They had Mean +/- SD age of 44.9 +/- 9.7 years; body mass index of 35.9 +/- 12.9 kg/m2 and apnea/hypopnea index (AHI) of 47.2 +/- 35.6. Both forms of therapy were equally effective in improving the symptoms and in reducing the AHI. Both forms of therapy were associated with frequent side effects and had similar patient compliance. At the end of the study, more patients (6-1) preferred F-CPAP to A-CPAP therapy. CONCLUSION: A-PAP was as effective as F-CPAP in the treatment of OSAH but was not associated with fewer side effects, better compliance, better satisfaction or increased patient preference.     

Autotitration positive airway pressure therapy in patients with obstructive sleep apnea who are intolerant of fixed continuous positive airway pressure

Compliance with continuous positive airway pressure (CPAP) therapy is one of the most difficult management problems for patients with obstructive sleep apnea (OSA). We postulated that autotitration positive airway pressure (APAP) may be effective in some patients who have an intolerance of fixed CPAP. The study was done to estimate how often patients who cannot tolerate fixed CPAP can tolerate APAP. We identified 25 patients seen in the Sleep Disorders Center who had been treated with fixed CPAP for OSA and were intolerant of CPAP therapy despite multiple efforts to improve tolerance. We substituted APAP therapy and measured subjective and objective compliance with treatment 1 month later. The primary end point was the number of patients who successfully tolerated the use of APAP at the end of 30 days, measured objectively by the device's compliance monitor. A positive outcome was defined as an average use of APAP that was greater than 3 h per night on more than 70% of possible nights. Of the 25 patients (mean age, 68 years; mean apnea-hypopnea index, 35), 11 were able to tolerate APAP therapy. The mean number of hours of use in these responders was 6.2; the mean percentage of nights of use among responders was 89%. Determinants of successful APAP use were an apnea-hypopnea index (AHI) less than 18, male sex, OSA related to rapid eye movement, and a high body mass index. APAP therapy may be an effective option in patients who do not tolerate fixed-CPAP therapy.     

Automatic CPAP titration with different self-setting devices in patients with obstructive sleep apnoea.

Autotitrating continuous positive airway pressure (CPAP) devices automatically adjust the pressure according to upper airway obstructions. The aim of this study was to compare the treatment effects of different automatic CPAP devices (AutoSet, Horizon and Virtuoso) with conventional CPAP in patients with obstructive sleep apnoea independently of financial manufacturer support. Twelve male patients with obstructive sleep apnoea were submitted to a crossover study protocol with overnight polysomnography for 6 consecutive nights. After diagnostic polysomnography, the CPAP pressure was manually titrated. Over the next 4 nights, the patients were treated with any one of the three automatic CPAP devices or fixed CPAP in random order. The apnoea/hypopnoea index on the diagnostic night was 67.3+/-21.7 events h(-1), and was significantly reduced to 0.7+/-1.2, 3.0+/-2.9, 2.3+/-2.5 and 12.0+/-13.6 events x h(-1) with the fixed CPAP, AutoSet, Horizon and Virtuoso devices respectively. An apnoea/ hypopnoea index of <5 events h(-1), an indicator of optimal treatment, was achieved in all patients with fixed CPAP and in 10 patients using the Autoset and Horizon devices, but in only six of the 12 using the Virtuoso. The mean pressure was significantly lower with the AutoSet and Virtuoso devices, but not with the Horizon as compared to fixed CPAP. The maximum pressure was significantly higher with the Horizon. It is concluded that automatic continuous positive airway pressure devices produce a significant reduction in apnoea/hypopnoea index; however, there is considerable difference in the efficacy of the various devices.     

Humidified nasal continuous positive airway pressure in obstructive sleep apnoea.

Heated humidification of nasal continuous positive airway pressure (nCPAP) reduces upper airway symptoms and improves initial use in obstructive sleep apnoea syndrome (OSAS). The present study aimed to assess the effect of heated humidification of nCPAP on upper airway symptoms and initial use in obstructive sleep apnoea. This study was of a randomised, crossover design. Subjects with polysomnographically confirmed OSAS were randomised to 3 weeks nCPAP treatment with heated humidification (nCPAP-humid) or placebo humidification (nCPAP pl-humid). Objective and subjective nCPAP use, upper airway symptoms, and treatment satisfaction were compared. Thirty seven of 42 patients completed the protocol. nCPAP-humid reduced the frequency of adverse upper airway symptoms. nCPAP use over 3 weeks was greater with nCPAP-humid compared with nCPAP pl-humid. No difference was found between the treatment arms in terms of subjective treatment satisfaction or alertness. Heated humidification of nasal continuous positive airway pressure reduces upper airway symptoms and is associated with a small increase in initial use but not subjective sleepiness or treatment satisfaction. The results support the use of heated humidification as a strategy to reduce side-effects related to continuous positive airway pressure but not routine initial use.     

Continuous positive airway pressure does not reduce blood pressure in nonsleepy hypertensive OSA patients.

Obstructive sleep apnoea (OSA) is associated with high cardiovascular morbidity and mortality. Several randomised controlled trials have shown that continuous positive airway pressure (CPAP) treatment of OSA reduces blood pressure (BP). This randomised, sham-placebo controlled crossover trial assesses whether CPAP produces a similar clinically significant fall in BP in hypertensive OSA patients, but without hypersomnolence. Thirty-five, nonsleepy, hypertensive patients with OSA were treated with CPAP for 1 month, randomised first to either therapeutic or sham-placebo (subtherapeutic CPAP, about 1 cmH(2)O pressure). The second months' alternative treatment followed a 2-week washout period. BP was measured over 24 h, before and at the end of the two treatment periods: mean 24-h BP was the primary outcome variable. There was no overall significant difference in mean 24-h BP: the change in mean 24-h BP on therapeutic CPAP was -2.1 mmHg (sd 8.1), and -1.1 mmHg (sd 8.1) on subtherapeutic CPAP, with a difference of 0.7 mmHg (95% confidence interval (CI) +2.9- -4.4). There was a small significant fall in Epworth Sleepiness Score, therapeutic (-1.4) versus sham (-0.3), and difference -1.2 (95% CI -2.0- -0.4), but no change in objective sleepiness. In nonhypersomnolent hypertensive patients with obstructive sleep apnoea, there is no significant fall in mean 24-h blood pressure with continuous positive airway pressure, in contrast to the fall seen in hypersomnolent patients with obstructive sleep apnoea.     

Established vascular effects of continuous positive airway pressure therapy in patients with obstructive sleep apnoea—an update

The aim of this review was to summarize the current data from randomised controlled trials (RCTs) on vascular effects of continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnoea (OSA). There is good evidence from RCTs that CPAP lowers blood pressure (BP) to a clinically significant amount. The effect seems to be dependent on the hours of nightly CPAP usage. Data from RCTs have also proven a beneficial effect of CPAP on measures of vascular function such as endothelial function and arterial stiffness. However, there is still a lack of evidence from RCTs proving that CPAP reduces vascular events and mortality.     

Continuous positive airway pressure treatment for sleep apnoea: compliance increases with time in continuing users.

Continuous positive airway pressure (CPAP) remains the best treatment for sleep apnoea syndrome (SAS). In the 1990s, many authors reported on daily compliance, but all of the studies utilised relatively short periods of follow-up that did not exceed a few years. The mean annual rate of CPAP use in patients with SAS was prospectively recorded. In the current study, the results are presented along with compliance data from patients who started CPAP between 1991 and 1998 and were still using it by the end of 2003. The cohort was chosen in order to obtain >or=5 yrs of follow-up for each patient. In total, there were 204 patients. For the whole group, mean+/-sd compliance reached 321+/-90 and 393+/-84 min after 1 and 10 yrs, respectively. There was no significant change in the first 2 yrs, with a significant increase from the third year onwards. Compliance, or its evolution over time, was not correlated either to the baseline polysomnographical data (except slightly for the CPAP pressure), to the difference of these data before and under CPAP therapy, to the age of retirement or to changes in the marital status. In conclusion, very long-term compliance with continuous positive airway pressure increases by a mean of 8 min.day-1 per year of follow-up in patients with sleep apnoea syndrome.     

Quality of life,compliance, sleep and nasopharyngeal side effects during CPAP therapy with and without controlled heated humidification

Purpose  

To determine the effect of a controlled heated breathing tube humidifier (cHH) on the quality of life (QOL), compliance and nasopharyngeal side effects during continuous positive airway pressure (CPAP) therapy in patients with obstructive sleep apnea syndrome (OSAS) in comparison with conventional CPAP.     

Effects of obesity upon genioglossus structure and function in obstructive sleep apnoea.

Obesity is a common feature of the obstructive sleep apnoea syndrome. It can influence the structure and function of skeletal muscles. However, its effects upon the upper airway muscles have not been explored directly. This study assessed the structure and function of the genioglossus in patients with obstructive sleep apnoea syndrome and in healthy subjects (with and without obesity, defined by a body mass index > 30 kg x m(-2)). Further, to investigate the effects of continuous positive airway pressure (CPAP) treatment, patients with obstructive sleep apnoea syndrome after at least 1 yr under CPAP were also studied. The study found that obese and nonobese patients showed different in vitro geniglossus endurance properties. In obese patients, geniglossus endurance was indistinguishable from normal while, nonobese patients, at diagnosis, showed increased genioglossus fatigability; this was not observed in patients treated with CPAP. By contrast, patients with obstructive sleep apnoea syndrome showed at diagnosis a higher percentage of type II fibres than controls and patients under CPAP treatment independently of obesity. This difference is mainly due to a predominance of subtype IIb fibre. This difference was not observed in the group of patients treated with CPAP. Genioglossus twitch force was normal in all patients. These results suggest that different pathogenic mechanisms may underlie the development of obstructive sleep apnoea syndrome in obese and nonobese patients. This observation may have potential clinical implications.     

Health utilities in evaluating intervention in the sleep apnoea/hypopnoea syndrome.

Formulating a rational health policy necessitates the ability to compare between different healthcare interventions and disease scenarios. Continuous positive airway pressure (CPAP) therapy with a conservative lifestyle strategy in sleep apnoea/hypopnoea syndrome (SAHS) was evaluated using health utility and quality-adjusted life years (QALYs) as outcome measures. A total 71 SAHS (apnoea/hypopnoea index > or = 15 h(-1)) patients completed a randomised, parallel group study over 3 months using utilities derived by the standard gamble approach (Usg) and European quality of life questionnaire (Euroqol) (Ueq). The severely impaired health status at baseline improved by 23% (Usg 0.32 to 0.55) adding 8 QALYs in the CPAP group, compared to a 4% improvement with 4.7 QALYs added in the lifestyle group (Usg 0.31 to 0.35). The Ueq showed a marginal change with CPAP (0.73 to 0.77) but did not demonstrate any improvement with lifestyle intervention. The health status impairment in sleep apnoea/hypopnoea syndrome patients is markedly improved by continuous positive airway pressure compared to a modest improvement with conservative lifestyle strategies using the standard gamble utility, which may be incorporated in effectiveness and economic analyses. The European quality of life questionnaire did not reflect a similar degree of impact and is probably not useful in this population.