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     

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.     

Benefit of continuous positive airway pressure on work quality in patients with severe obstructive sleep apnea

Sleep and Breathing - The objective of this prospective study was to assess the effect of CPAP therapy on job productivity and work quality for patients with severe obstructive sleep apnea (OSA). A...     

The effect of continuous positive airway pressure on glucose control in diabetic patients with severe obstructive sleep apnea

Obstructive sleep apnea (OSA) is independently associated with glucose intolerance and insulin resistance, and recent studies have shown that continuous positive airway pressure (CPAP) improves insulin sensitivity. The objective of this study was to describe the change in glycosylated hemoglobin (HbA1c) after treatment with CPAP in patients with type 2 diabetes mellitus and OSA. To test this hypothesis, we performed a retrospective analysis of 38 patients seen in the sleep clinic of an urban public teaching hospital. All patients had OSA and type 2 diabetes mellitus, and their diabetic medication regimen had remained unchanged during the period of CPAP therapy. Sixty-one percent were men, body mass index was 42±9.5 kg/m², and the Apnea–Hypopnea Index was 53±36 per hour. HbA1c before therapy with CPAP was 7.8±1.4% and decreased to 7.3±1.3% after 134±119 days of therapy (p<0.001). Treatment with CPAP leads to a clinically significant drop in HbA1c in patients with type 2 diabetes mellitus and severe OSA.     

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.     

Short-term effects of continuous positive airway pressure on oxidative stress in severe sleep apnea

Sleep and Breathing - Obstructive sleep apnea (OSA) is associated with oxidative stress that is involved in the pathogenesis of cardiovascular and metabolic complications. The concentrations of...     

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.     

The effects of nasal continuous positive airway pressure on platelet activation in obstructive sleep apnea syndrome

OBJECTIVE: A case-controlled study to assess the effects of nasal continuous positive airway pressure (CPAP) on platelet activation in patients with obstructive sleep apnea (OSAS) syndrome. METHODS: We recruited 65 patients with suspected OSAS for this study. Blood samples were taken with the patient in the supine position in the morning immediately after polysomnography, and 1 night and 3 months after the start of nasal CPAP therapy to measure an index of platelet activation (IPA+), which reflected both the quantity and quality of platelet activation. Significant OSAS was defined as an apnea-hypopnea index (AHI) of > or = 10 events per hour. RESULTS: There were 42 patients with significant OSAS and 23 control subjects with AHI < 10 events per hour. The mean (+/- SD) age for the OSAS patients was 48 +/- 9 years, the mean body mass index was 30.7 +/- 4.8, the mean AHI was 47 +/- 25 events per hour, the mean arousal index (AI) was 37 +/- 23 events per hour, and the mean minimum arterial oxygen saturation was 74 +/- 11%. Following multiple linear regression analyses of the clinical and polysomnography parameters, AI was the independent factor that correlated best with the baseline IPA+ (beta-coefficient, 0.386; p = 0.006). Following nasal CPAP treatment with a mean objective CPAP compliance of 3.9 +/- 1.9 h per night, there was a significant decrease in IPA+ from 15.1 +/- 12.2 U (at baseline) to 12.2 +/- 5.2 U (p < 0.001) and 9.8 +/- 4.3 U (p = 0.005), respectively, after 1 night and 3 months, whereas no significant change was noted among the control subjects. Using univariate analysis of variance to compare the changes in IPA+ between the two groups at 3 months with adjustment for the baseline value, nasal CPAP reduced IPA+ by 5.63 (SE, 1.85), whereas IPA+ increased in control subjects by 1.33 (SE, 1.27) [least-squared mean difference between groups, 3.34; 95% confidence interval, 0.42 to 6.26; p = 0.026]. CONCLUSIONS: OSAS, through repeated episodes of arousals, may lead to platelet activation, which can be reduced by nasal CPAP therapy.     

Acute effects of automated continuous positive airway pressure on blood pressure in patients with sleep apnea and hypertension

BACKGROUND: The obstructive sleep apnea-hypopnea syndrome (OSAHS) is characterized by repetitive upper airway obstructions during sleep, and it might cause cardiovascular complications such as myocardial infarction, arrhythmias, and systemic and pulmonary hypertension. Objectives: We investigated the acute effects of automatic continuous positive airway pressure (automated CPAP) on blood pressure in patients with OSAHS and hypertension. METHODS: Polysomnography was used and ambulatory blood pressure measurements were done in 12 patients with OSAHS. Blood pressure and heart rate were measured at night (10 p.m. to 6 a.m.) and during the day (6 a.m. to 10 p.m.). During these periods systolic, diastolic and mean blood pressure and heart rate of the patients on the diagnostic day were compared with those on the treatment day. RESULTS: Patients had moderate or severe OSAHS; their mean age was 52.8+/-4.2 years. Systolic, diastolic and mean blood pressure and heart rate between the diagnostic and treatment day were not significantly different. Standard deviations of all these parameters during the night of the treatment day (9.1+/-4.5, 7.5+/-3.3, 8.0+/-3.0 mm Hg, and 4.8+/-1.5 beats/min, respectively) were significantly lower than during the night of the diagnostic day (12.6+/-4.9 mm Hg, p=0.023, 10.8+/-3.5 mm Hg, p=0.004, 11.6+/-4.4 mm Hg, p=0.006 and 6.9+/-1.6 beats/min, p=0.003, respectively). We did not find similar results during daytime periods. CONCLUSIONS: Automated CPAP therapy in patients with sleep apnea and hypertension did not decrease systolic and diastolic blood pressures and heart rates acutely. However, it might reduce the variability of these parameters during sleep in patients, but not during the day. It might be suggested that automated CPAP reduces cardiovascular morbidity of OSAHS via stabilizing heart rate and blood pressure during sleep.     

持续正压通气治疗阻塞性睡眠呼吸暂停低通气综合征伴高血压的护理

目的研究持续气道正压通气(CPAP)治疗阻塞性睡眠呼吸暂停低通气综合征(OSAHS)伴高血压的作用及护理。方法45例OSAHS伴高血压患者使用CPAP,每晚治疗8h。定时测量血压,并辅以积极的护理措施,观察患者治疗前后的血压变化。结果治疗后血压有所下降(P<0.05),下降时间为3～14d,平均(5±2.5)d。结论CPAP治疗OSAHS伴高血压是一种有效方法,护理有其特殊性和重要性。     

The effects of continuous positive airway pressure therapy on mean platelet volume in patients with obstructive sleep apnea

Previous studies have reported increased platelet activation and aggregation in patients with obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) treatment has been shown to decrease platelet activation. We aimed to study the effects of nasal CPAP therapy has on MPV values in patients with severe OSA. Thirty-one patients (21 men; mean age 53.8?±?9.2 years) with severe OSA (AHI?>?30 events/hour) constituted the study group. An age, gender and body mass index (BMI) matched control group was composed 25 subjects (14 men; mean age 49.6?±?8.5 years) without OSA (AHI?<?5 events/hour). We measured MPV values in patients with severe OSA and control subjects and we measured MPV values after 6 months of CPAP therapy in severe OS patients. The median (IQR) MPV values were significantly higher in patients with severe OSA than in control group (8.5 [8.3–9.1] vs. 8.3 [7.5–8.8] fL; p?=?0.03). The platelet counts were significantly lower in patients with severe OSA than in control group (217.8?±?45.9 vs. 265.4?±?64.0?×?10⁹/L; p?=?0.002). The six months of CPAP therapy caused significant reductions in median (IQR) MPV values in patients with severe OSA (8.5 [8.3–9.1] to 7.9 [7.4–8.2] fL; p?<?0.001). Six months of CPAP therapy caused significant increase in platelet counts when compared with baseline values (217.8?±?45.9 to 233.7?±?60.6?×?10⁹/L; p?<?0.001). We have found that the MPV values of patients with severe OSA were significantly higher than those of the control subjects and 6 months CPAP therapy caused significant reductions in the MPV values in patients with severe OSA.     

The effects of continuous positive airway pressure therapy on mean platelet volume in patients with obstructive sleep apnea

Previous studies have reported increased platelet activation and aggregation in patients with obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) treatment has been shown to decrease platelet activation. We aimed to study the effects of nasal CPAP therapy has on MPV values in patients with severe OSA. Thirty-one patients (21 men; mean age 53.8?±?9.2 years) with severe OSA (AHI?>?30 events/hour) constituted the study group. An age, gender and body mass index (BMI) matched control group was composed 25 subjects (14 men; mean age 49.6?±?8.5 years) without OSA (AHI?相似文献   

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。     

Sympathetic chemoreflex responses in obstructive sleep apnea and effects of continuous positive airway pressure therapy

BACKGROUND: Sympathetic nerve activity is increased in awake and regularly breathing patients with obstructive sleep apnea (OSA). Over time, repetitive hypoxic stress could alter sympathetic chemoreflex function in OSA. METHODS: We determined the responses to acute hypoxia (fraction of inspired oxygen of 0.1, for 5 min), static handgrip exercise, and the cold pressor test (CPT) in 24 patients with OSA (age, 50 +/- 3 years [mean +/- SEM]; apnea-hypopnea index, 47 +/- 6 events per hour) and in 14 age- and weight-matched nonapneic control subjects. Muscle sympathetic nerve activity (MSNA) [peroneal microneurography], BP, and ventilation were monitored. RESULTS: Basal MSNA was higher in OSA patients compared to control subjects (45 +/- 4 bursts per minute vs 33 +/- 4 bursts per minute, respectively; p < 0.05). Furthermore, compared to control subjects, the MSNA responses to hypoxia were markedly enhanced in OSA (p < 0.001). Whereas the ventilatory responses to hypoxia tended to be increased in OSA (p = 0.06), the BP responses did not differ between the groups (p = 0.45). The neurocirculatory reflex responses to handgrip exercise and to the CPT were similar in the two groups (p = not significant). In OSA patients who were retested after 1 to 24 months of continuous positive airway pressure (CPAP) therapy (n = 11), basal MSNA (p < 0.01) and the responses of MSNA to hypoxia (p < 0.01) decreased significantly, whereas the ventilatory responses remained unchanged (p = 0.82). CONCLUSION: These data suggest that the sympathetic responses to hypoxic chemoreflex stimulation are enhanced in OSA and may normalize in part following 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.     

CPAP治疗重度OSAHS的疗效观察

目的 观察持续气道正压通气(CPAP)治疗重度阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的疗效、影响因素.方法 36例确诊为重度OSAHS的患者经CPAP治疗后,观察其治疗前后的呼吸暂停低通气指数(AHI)、夜间最低血氧饱和度(SaO2)及临床症状的变化.结果 治疗后AHI明显下降,夜间最低SaO2及临床症状明显改善.结论 CPAP是治疗重度OSAHS的有效方法.患者的依从性对重度OSAHS的治疗有决定性的意义.     

持续气道正压通气对于阻塞性睡眠呼吸暂停相关性高血压的治疗效果研究进展

阻塞性睡眠呼吸暂停常影响睡眠质量并引起心血管疾病,其中高血压发病率最高。目前对于阻塞性睡眠呼吸暂停与高血压之间的关系及机制仍在探索中,而持续气道正压通气作为阻塞性睡眠呼吸暂停的有效治疗方法,对于血压的降压作用说法不一。了解阻塞性睡眠呼吸暂停与高血压之间的关系机制及持续气道正压通气的治疗效果,将有助于更好的临床实践。     

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.