Nasal continuous positive airway pressure therapy in obstructive sleep apnea syndrome]

Sixteen patients (male: 14, female: 2, 41-72 yrs, mean 57.5 yrs) with OSAS were treated by nCPAP in our hospital since 1987. Respiratory disturbance index ranged from 16.5 to 83.1. The longest apnea duration was 35.0-120.5 seconds before the treatment. Two patients were treated with Sleep Easy III (Respironics Inc.) and others with a home made instruments. nCPAP was set at a pressure of 5 to 10 cm H2O. 12 patients (75%) tolerated the device but 4(25%) did not. Polysomnographic parameters before and after nCPAP therapy were compared. The longest apnea duration was 63.1 +/- 23.5 to 40.9 +/- 27.4 seconds (P less than 0.001) and the lowest saturation oxygen was 55.1 +/- 20.4% to 71.4 +/- 18.6% (P less than 0.05). The sleep structure improved but not significant statistically. One of them used nCPAP at home for more than two. years and showed a good long term effect. We concluded that nCPAP is an effective and safe treatment for OSAS. However, patients may be uncomfortable because of the wearing of the nasal mask during sleep.     

Treatment of obstructive sleep apnea, other than with continuous positive airway pressure

Treatment, other than with continuous positive airway pressure, for patients with obstructive sleep apnea remains an active area of investigation. The long-established behavior modification approaches (eg, weight loss and avoidance of alcohol and sedatives) are applicable to many patients, though unlikely to be curative. Oral appliances and surgical techniques are used, although treatment success is hindered by the site-specific nature of the therapies. These treatments are traditionally used for the patient with mild sleep apnea, but more recent studies are questioning their possible benefits in a moderate-to-severe apnea patient population. Surgical techniques range from uvulopalatopharyngoplasty and more extensive skeletal modifications (maxillomandibular advancement), to laser-assisted uvulopalatoplasty and newer minimally invasive techniques. Preoperative evaluation, patient selection, and measures of success vary somewhat between publications, making comparison of treatments and their application to the individual patient challenging.     

Prediction of continuous positive airway pressure in obstructive sleep apnea

Continuous positive airway pressure (CPAP) prediction formulas can potentially simplify the treatment of obstructive sleep apnea (OSA). However, they can be difficult to derive and validate. We tested a statistical method to derive and validate a CPAP prediction formula using the same sample population. Seventy-six OSA patients underwent polysomnography and CPAP titration. Anthropometric measures, sleep parameters, and the Epworth sleepiness scale (ESS) were evaluated as predictors. All subsets regression was used to determine the optimum number of variables in the model. The Bayes information criterion was used to find the best-fit model. The model was then evaluated by a tenfold cross-validation procedure. Subjects were obese (BMI 31.3 ± 5.4) and had significant daytime somnolence (ESS 11.9 ± 5). Mean respiratory disturbance index (RDI) was 53.5 ± 31.3. The ESS was not predictive of titrated CPAP. The best-fit model included three variables (CPAP_pred = 30.8 + RDI × 0.03 − nadir saturation × 0.05 − mean saturation × 0.2). This model explained 67% of the variance. Our data and the literature suggest that a combination of two to three factors is predictive of titrated CPAP: RDI, oxyhemoglobin saturation, and obesity. Except for RDI, the specific factors vary in each population. A CPAP prediction formula that explains a high proportion of the titrated CPAP variance can be easily derived from parameters measured during the diagnostic work-up of OSA patients using a unique statistical model that allows derivation and validation of the formula in the same test population.     

Effect of continuous positive airway pressure vs placebo continuous positive airway pressure on sleep quality in obstructive sleep apnea

STUDY OBJECTIVES: Continuous positive airway pressure (CPAP) therapy has become the treatment of choice for obstructive sleep apnea (OSA). However, the efficacy of CPAP therapy has not been evaluated against a suitable control. We investigated the effectiveness of CPAP therapy in improving sleep quality in patients with OSA. We hypothesized that CPAP improves sleep quality. PATIENTS: Forty-eight CPAP-naive OSA patients were evaluated. None were receiving antihypertensive medications, and none had major medical illnesses. DESIGN: Patients were randomized to receive either CPAP or placebo CPAP (CPAP at an ineffective pressure) for 7 days in a double-blind fashion. Forty-one patients completed the protocol. Sleep quality variables, arousals, sleep arterial oxygen saturation (SaO(2)), and respiratory disturbance index (RDI) were assessed at baseline, after 1 day of treatment, and after 7 days of treatment. Repeated measures analysis of variance was used to evaluate the effects of treatment, time, and the interaction of the two. RESULTS: As expected, CPAP lowered RDI and number of arousals, and increased SaO(2) over time (p = 0.001). Contrary to expectations, both CPAP and placebo CPAP had comparable effects on sleep quality as assessed by sleep architecture, sleep efficiency, total sleep time, and wake after sleep onset time. CONCLUSIONS: This study confirms the effectiveness of CPAP in lowering the number of arousals and the RDI, and in raising SaO(2). However, our data suggest that short-term CPAP is no different than placebo in improving sleep architecture. Further evaluation of the effectiveness of CPAP using a suitable placebo CPAP in prospective randomized studies is needed     

经鼻持续气道内正压通气治疗阻塞性睡眠呼吸暂停低通气综合征进展

阻塞性睡眠呼吸暂停低通气综合征(OSAHS)是一种发病率较高并具有一定潜在危险的疾病,经鼻持续气道内正压通气(nCPAP)目前已成为治疗中、重度OSAHS患者的首选措施。本文介绍了应用nCPAP的治疗机制、对各器官的治疗作用、压力水平的调节、影响其成功的因素、以及经鼻面罩正压机械通气治疗OSAHS新模式和治疗的副作用等进行了综述。     

Arbitrary-pressure continuous positive airway pressure for obstructive sleep apnea syndrome

Current resources are inadequate to meet the demand for polysomnography, resulting in long waiting lists. This study aimed to evaluate the role of arbitrary-pressure continuous positive airway pressure (CPAP) as a method to reduce delays in commencing treatment. The study was of an open, randomized, parallel design. Ninety-one subjects with obstructive sleep apnea syndrome were randomized to either arbitrary-pressure CPAP based on body mass index before treatment polysomnography or to CPAP at settings determined by polysomnography. Both interventions resulted in similar improvements in clinical outcomes as determined by Epworth Sleepiness Score, Short Form-36 Quality of Life questionnaire, objective compliance, and subjective attitudes to treatment. There was higher sleep efficiency at treatment polysomnography in the group commenced at arbitrary pressure (81.8 +/- 10.1% [mean +/- SD] compared with 72.2 +/- 18.0%, p = 0.01). Subjects unable to tolerate CPAP were identified by the use of arbitrary pressure, leading to a reduction in the proportion of "wasted" treatment polysomnograms (studies performed in subjects not persisting with treatment) relative to commencing therapy after treatment polysomnography (3 of 39 compared with 12 of 35, p = 0.01). This approach to initiating treatment with CPAP appears feasible when there are long waiting lists for polysomnography.     

Long-term acceptance of continuous positive airway pressure in obstructive sleep apnea

We studied the long-term acceptability of nasal continuous positive airway pressure (CPAP) treatment in 168 consecutive patients, 147 with obstructive sleep apnea (OSA) and 21 with snoring. Follow-up was between 1.5 and 78 months. At latest follow-up 107 of 168 (64%) were still using CPAP. Acceptance of CPAP was least for patients with snoring alone (6 of 21 persisted) and best for patients with both excessive daytime somnolence and severe hypoxemia (minimum SaO2 less than 75%), of whom 40 of 45 (89%) persisted with treatment. Patients with excessive daytime somnolence but without severe hypoxemia were less tolerant of CPAP (39 of 71, 55%, persisted) than patients with no symptoms of excessive somnolence but with severe hypoxemia (21 of 30, 70%, persisted). The most common reasons for discontinuing CPAP were intolerance of the mask (26 of 61), the inconvenience of treatment (16 of 61), and the lack of symptomatic benefit from treatment (10 of 61). We concluded that long-term acceptance of CPAP was difficult to predict in advance but that it was most likely in patients with the most severe sleep apnea. Because intolerance of the mask and inconvenience were the most common reasons for ceasing treatment, improvements in the design of CPAP systems and careful patient training may improve the acceptability of CPAP substantially.     

Nasal nitric oxide improved by continuous positive airway pressure therapy for upper airway inflammation in obstructive sleep apnea

Purpose

In this report, we examined the association between obstructive sleep apnea (OSA) and upper and lower airway inflammation based on nitric oxide (NO) measurements.

Methods

Study subjects included 51 consecutive participants. Sleep-disordered breathing was evaluated by a type 3 portable monitor and quantified by respiratory disturbance index (RDI). Airway inflammation was noninvasively analyzed by the measurement of nasally and orally exhaled NO; nasal value was presented as nasally exhaled NO minus orally exhaled NO. In 15 patients prescribed nasal continuous positive airway pressure (nCPAP) therapy, exhaled NO was re-evaluated in 10.7 ± 6.3 months after nCPAP therapy.

Results

Nasal NO was significantly higher in patients with severe OSA (RDI ≥ 30/h) than those with non-OSA (RDI < 10/h) (76.9 ± 26.0 ppb vs. 47.9 ± 22.0 ppb, respectively, p = 0.016) and correlated with RDI (rho = 0.36, p = 0.0099), whereas orally exhaled NO did not differ between non-OSA and OSA patients and was not correlated with RDI. In 15 patients, nasal NO after nCPAP therapy was significantly decreased than that before nCPAP therapy (81.9 ± 31.2 ppb vs. 53.7 ± 27.2 ppb, respectively, p = 0.0046); in 11 patients having good compliance to nCPAP therapy (nCPAP use >4 h per night on more than 70% of nights), this association was more remarkable.

Conclusions

In OSA, upper but not lower airway inflammation can be increased by repetitive collapse of the upper airway. Future studies are required to determine the role of nasal NO in OSA.

     

经鼻持续气道正压通气对阻塞性睡眠呼吸暂停综合征的综合疗效

经鼻持续气道正压通气（CPAP）是目前治疗阻塞性呼吸暂停综合征（OSAS）最有效的内科治疗方法,通过向气道内增加一定程度的正压,保持上气道通畅,消除患者夜间缺氧,改善患者夜间打鼾,白天嗜睡等临床症状,恢复睡眠结构,并治疗与此相关的各系统疾病,提高患者长期的生活质量。     

Nasal continuous positive airway pressure and weight loss improve swallowing reflex in patients with obstructive sleep apnea syndrome

We have recently reported that swallowing reflex is impaired in patients with obstructive sleep apnea syndrome (OSAS). However, the effects of OSAS treatment on swallowing function in these patients have not been reported. Here we report 2 cases of OSAS in whom swallowing reflex was impaired before the start of nasal continuous positive airway pressure (NCPAP) and improved 1 year after NCPAP. These cases suggest that impaired swallowing reflex may be reversible by OSAS treatment.     

Long-term compliance with nasal continuous positive airway pressure therapy of obstructive sleep apnea

In an attempt to identify predictors of long-term compliance with nasal continuous positive airway pressure (CPAP), we reviewed the records of 125 patients with obstructive sleep apnea (OSA) referred to our center for nasal CPAP trials. Severity of sleep apnea, sleep staging, daytime hypersomnolence, effectiveness of nasal CPAP, previous palatal surgery, and adverse reactions were compared in compliant and noncompliant patients. Nineteen patients did not tolerate a nasal CPAP trial in the laboratory or refused home nasal CPAP therapy. Ten patients were unavailable for follow-up. Of the remaining 96 patients, 23 (24 percent) had discontinued therapy, while 73 (76 percent) were still using nasal CPAP at 14.5 +/- 10.7 months (mean +/- SD). There were no statistically significant differences between the compliant and noncompliant patients in baseline apnea plus hypopnea index (AHI), baseline sleep staging, AHI while receiving nasal CPAP, sleep staging while receiving nasal CPAP, or frequency of adverse reactions during therapy. Severe daytime sleepiness was present in 65 of the 73 compliant patients and in 12 of the 23 noncompliant patients (p less than 0.05). Ten of 43 in the compliant group had previous palatal surgery compared with ten of 23 noncompliant patients (p less than 0.05). Our data confirm earlier observations in smaller samples that compliant and noncompliant patients have equally severe sleep apnea and good initial responses to nasal CPAP. Long-term compliance with nasal CPAP may be associated with the severity of daytime hypersomnolence on presentation. Previous palatal surgery was more frequent in patients who did not tolerate long-term nasal CPAP therapy.     

Lung volume and continuous positive airway pressure requirements in obstructive sleep apnea

Previous studies have demonstrated that lung volume during wakefulness influences upper airway size and resistance, particularly in patients with sleep apnea. We sought to determine the influence of lung volume on the level of continuous positive airway pressure (CPAP) required to prevent flow limitation during non-REM sleep in subjects with sleep apnea. Seventeen subjects (apnea-hypopnea index, 42.6 +/- 6.2 [SEM]) were studied during stable non-REM sleep in a rigid head-out shell equipped with a positive/negative pressure attachment for manipulation of extrathoracic pressure. An epiglottic pressure catheter plus a mask/pneumotachometer were used to assess flow limitation. When lung volume was increased by 1,035 +/- 22 ml, the CPAP level could be decreased from 11.9 +/- 0.7 to 4.8 +/- 0.7 cm H(2)O (p < 0.001) without flow limitation. The decreased CPAP at the same negative extrathoracic pressure yielded a final lung volume increase of 421 +/- 36 ml above the initial value. Conversely, when lung volume was reduced by 732 +/- 74 ml (n = 8), the CPAP level had to be increased from 11.9 +/- 0.7 to 17.1 +/- 1.0 cm H(2)O (p < 0.001) to prevent flow limitation, with a final lung volume decrease of 567 +/- 78 ml. These results demonstrate that relatively small changes in lung volume have an important effect on the upper airway in subjects with sleep apnea during non-REM sleep.     

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.     

Efficacy of continuous positive airway pressure on arrhythmias in obstructive sleep apnea patients

The purpose of this study was to determine the relationship between obstructive sleep apnea (OSA) and cardiovascular disorders in a large Japanese population, and to assess the efficacy of continuous positive airway pressure (CPAP) in the treatment of OSA-associated arrhythmias. The study population comprised 1394 Japanese subjects (1086 men and 308 women) who were divided into four groups on the basis of polysomnography (PSG) analysis as follows: the no sleep apnea (N-SA) group (n = 44, apnea-hypopnea index [AHI] < 5), the mild OSA (Mi-OSA) group (n = 197, 5 < AHI < 15), the moderate OSA (Mo) group (n = 368, 15 < AHI < 30), and severe OSA (SOSA) group (n = 785, AHI < 30). The following baseline characteristics were significantly associated with OSA: age (P < 0.001), gender (P < 0.001), body mass index (P < 0.001), hypertension (P < 0.001), diabetes (P = 0.009), and hyperlipidemia (P = 0.013). In the OSA group, PSG revealed the predominance of paroxysmal atrial fibrillation (PAF) (P = 0.051), premature atrial complex short run (P < 0.005), premature ventricular complex (PVC, P = 0.004), sinus bradycardia (P = 0.036), and sinus pause (arrest >2 s, P < 0.001) during the PSG recording. A total of 316 patients from the group underwent CPAP titration and were then re-evaluated. Continuous positive airway pressure therapy significantly reduced the occurrences of PAF (P < 0.001), PVC (P = 0.016), sinus bradycardia (P = 0.001), and sinus pause (P = 0.004). The results of this study demonstrate a significant relationship between OSA and several cardiac disorders, and also demonstrate the efficacy of CPAP in preventing OSA-associated arrhythmias in a large population of Japanese patients.     

Nocturnal continuous positive airway pressure decreases daytime sympathetic traffic in obstructive sleep apnea

BACKGROUND: Patients with obstructive sleep apnea (OSA) have high levels of muscle sympathetic nerve activity (MSNA). We tested the hypothesis that long-term continuous positive airway pressure (CPAP) treatment will decrease MSNA in OSA patients. METHODS AND RESULTS: We measured blood pressure, heart rate, and MSNA in 11 normotensive, otherwise healthy patients with OSA who were treated with CPAP. The measurements were obtained at baseline and after 1 month, 6 months, and 1 year of CPAP treatment. These measurements were compared with those recorded in 9 otherwise healthy OSA patients who were not treated with CPAP for 1 year. In both untreated and treated patients, blood pressure and heart rate did not change over time. MSNA was similar during repeated measurements in the untreated group. By contrast, MSNA decreased significantly over time in patients treated with CPAP. This decrease was evident after both 6 months and 1 year of CPAP treatment (P=0.02 for both). CONCLUSIONS: CPAP treatment decreases muscle sympathetic traffic in patients with OSA. This effect of CPAP is evident only after an extended duration of therapy.     

Effect of nocturnal nasal continuous positive airway pressure on blood pressure in obstructive sleep apnea

Obstructive sleep apnea (OSA) is a very common risk factor for hypertension, and continuous positive airway pressure (CPAP) has been widely used to treat OSA. We conducted a meta-analysis of randomized, controlled trials to evaluate the effects of CPAP on blood pressure, reported as either a primary or secondary end point, among patients with OSA. Studies were retrieved by searching Medline (January 1980 to July 2006), the Cochrane Database of Systematic Reviews, conference abstracts, and bibliographies of review and original articles. From 255 relevant reports, 16 randomized clinical trials were selected that compared CPAP to control among participants with OSA, had a minimum treatment duration of 2 weeks, and reported blood pressure changes during the intervention or control period. Data on sample size, participant characteristics, study design, intervention methods, duration, and treatment results were independently abstracted by 2 investigators using a standardized protocol. Data from 16 trials representing 818 participants were examined using a random-effects model. Mean net change in systolic blood pressure for those treated with CPAP compared with control was -2.46 mm Hg (95% CI: -4.31 to -0.62); mean net change in diastolic blood pressure was -1.83 mm Hg (95% CI: -3.05 to -0.61); and mean net change in mean arterial pressure was -2.22 mm Hg (95% CI: -4.38 to -0.05). Net reductions in blood pressure were not statistically different between daytime and nighttime. These results indicate that CPAP decreases blood pressure among those with OSA and may help prevent hypertension.     

Periodic leg movements in sleep following treatment of obstructive sleep apnea with nasal continuous positive airway pressure

Periodic leg movements in sleep are shown to be a common finding in patients with OSA and may become evident or increase in severity after treatment of the OSA with NCPAP. Periodic leg movements in sleep were measured during baseline polysomnography, a NCPAP treatment trial, and a repeat NCPAP recording in 33 patients treated with NCPAP for OSA. During baseline PSG, nine patients had five or more PLMS per hour of sleep (index), while 14 patients had a PLMSI of 5 or more during the NCPAP trial and the repeat NCPAP recording. Among those patients with a PLMSI of 5 or more during repeat NCPAP studies, the PLMSI showed a significant increase from baseline to initial NCPAP (16.9 +/- 25.3 vs 39.3 +/- 29.4; p less than 0.001) and from baseline to repeat NCPAP (16.9 +/- 25.3 vs 42.9 +/- 39.8; p less than 0.05). The number of PLMS associated with electroencephalographic arousal also increased significantly from baseline to initial NCPAP (4.3 +/- 7.4 vs 9.7 +/- 8.9; p less than 0.05) and from baseline to repeat NCPAP (4.3 +/- 7.4 vs 16.5 +/- 18.6; p less than 0.05). The 14 patients with a PLMSI of 5 or more on the repeat NCPAP had significantly more stage 1 sleep and less REM sleep than 19 patients with a PLMSI of less than 5. Bilateral anterior tibialis EMG must be measured during NCPAP recordings in order to recognize sleep disruption caused by PLMS.