Effect of continuous positive airway pressure on ambulatory BP in patients with sleep apnea and hypertension: a placebo-controlled trial

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for arterial hypertension. Several controlled trials have investigated the effect of continuous positive airway pressure (CPAP) on BP in patients with OSAS, but its effect on hypertensive patients has not been analyzed specifically. OBJECTIVE: To analyze the effect of CPAP on ambulatory BP in patients with OSAS and hypertension who were undergoing antihypertensive treatment. Design and patients: We conducted a parallel, randomized, placebo-controlled trial in 68 patients with OSAS and hypertension, who were receiving treatment with antihypertensive medication. Patients were randomly allocated to either therapeutic or subtherapeutic CPAP for 4 weeks. Ambulatory BP was registered at baseline and after treatment. Antihypertensive treatment was not changed during the study. Changes in BP were assessed on an intention-to-treat basis. RESULTS: There were no baseline differences in the apnea-hypopnea index, comorbidities, or ambulatory BP between groups. Objective compliance with CPAP was similar in both the therapeutic and subtherapeutic groups (5.0 +/- 1.4 h/d vs 4.4 +/- 1.9 h/d, respectively; p = 0.13 [mean +/- SD]). There was a small and statistically nonsignificant decrease (- 0.3 +/- 6.3 mm Hg vs - 1.1 +/- 7.9 mm Hg; difference, - 0.8 mm Hg [95% confidence interval, - 2.7 to 4.3]; p = 0.65) in 24-h mean BP (24hMBP) in both subtherapeutic and therapeutic groups after 4 weeks of treatment. No significant changes in systolic, diastolic, daytime, or nighttime BP were observed. The normal circadian dipper pattern was restored in a higher proportion of patients in the therapeutic group compared to the subtherapeutic CPAP group, although differences were not significant (11 of 32 patients vs 3 of 25 patients; odds ratio, 3.84; 95% confidence interval, 0.82 to 20.30; p = 0.10). There was no correlation between the magnitude of change in 24hMBP and CPAP compliance, OSAS severity, or number of antihypertensive drugs used. CONCLUSION: Four weeks of CPAP did not reduce BP in patients with OSAS and hypertension who were treated with antihypertensive medication, compared to placebo group.     

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.     

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.     

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.     

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     

Long-term adherence to nasal continuous positive airway pressure therapy by hypertensive patients with preexisting sleep apnea

Background and objectiveAlthough positive screening for and treatment of obstructive sleep apnea (OSA) have been recommended for patients with cardiovascular problems, patient adherence to nasal continuous positive airway pressure (CPAP) therapy primarily for a cardiovascular concern is unknown. Therefore, this study aimed to determine the adherence to CPAP therapy by hypertensive patients with OSA after a screening test performed regardless of OSA-related symptoms.Subjects and methodsCPAP therapy was administered to 194 of the 1365 hypertensive patients who underwent the screening. The monthly dropout from CPAP therapy and the adequate use level (4 h every night, 70% days in a month) were assessed using the Kaplan–Meier analysis over a 3-year follow-up period.ResultsOf the patients, 106 (55%) refused or abandoned the therapy by the end of the follow-up period (adherence, 45%). An adequate use level was maintained by 76 patients (39%). Most of the patients’ background characteristics, including age, sex, Epworth sleepiness scale scores, and parameters obtained on polysomnography, were not related to adherence or adequate use level. The good-compliance level on the first visit after CPAP therapy introduction was most strongly related to adherence (95% CI, 0.05–0.32; p < 0.001) and adequate use level (95% CI, 0.06–0.33; p < 0.05). Fourth quartile of apnea hypopnea index value (greater than 67/h) was also related to adherence (95% CI, 0.21–0.98; p < 0.02) and adequate use level (95% CI, 0.19–0.88; p < 0.05).ConclusionsThe adherence and use level in this population may not be satisfactory but are comparable with those in previous sleep center reports treating symptomatic OSA patients. Thus, the present results would encourage hypertensive patients to undergo positive screening for OSA, regardless of OSA-related symptoms. However, an outcomes study with the same cohort is needed.     

Influence of continuous positive airway pressure on sleep apnea-related desaturation in sleep apnea patients

To investigate the influence of nasal continuous positive airway pressure (CPAP) on apnea-related desaturation, we compared the sleep apnea-related desaturations obtained during a poly somnographic study before and during nasal CPAP in 15 sleep apnea patients. An individual desaturation curve was determined with a regression analysis by plotting the lowest SaO₂ value reached during each apnea against its duration; these data were collected throughout the night. At baseline, we only considered the apneas with a preapneic SaO₂ value greater than 90% and a minimal SaO₂ value above or equal to 60%. For the CPAP study, the preapneic Sa0₂ value also had to be within 2% the baseline value for the apneas to be retained. Due to the restriction criteria imposed to characterize apnea-related Sa0₂ falls, residual apneas still had to be recorded with CPAP. These data were analyzed separately for obstructive apnea for non-rapid eye movement (REM) and REM sleep stages. A desaturation curve was obtained from 10 sec to a variable upper limit that corresponded to the longest apnea duration commonly reached during both baseline and CPAP for a given apnea-type and sleep stage. The individual apnea-related Sa0₂ fall was characterized by measuring a desaturation area corresponding to the area under the curve. It was expressed in % Sa0₂/sec of apnea. CPAP reduced the number of apneas per hour of sleep from 37.5 ± 6.5 (mean ± SEM) to 14.3 3.7 (p = 0.001), and improved the whole night SaO₂, level as estimated by a cumulative SaO₂ curve. The mean apnea duration was reduced from 22.9 ± 1.5 sec at baseline to 16.8 ± 0.5 sec during CPAP therapy (p = 0.005). The preapneic SaO₂ value was 94.8 ± 0.3% at baseline and 95.5 ± 0.2% during CPAP (p = 0.5). The desaturation area decreased from 267 ± 48% SaO₂/sec at baseline to 152 ± 41% Sa0₂/sec during CPAP (p < 0.001). We conclude that CPAP improves the apnea-related desaturation independently of the shortening of apneas and of any difference in the preapneic SaO₂ value.     

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。     

Daytime pulmonary hypertension in patients with obstructive sleep apnea: the effect of continuous positive airway pressure on pulmonary hemodynamics.

BACKGROUND: Limited information exists regarding the development of pulmonary hypertension in patients with obstructive sleep apnea (OSA) in the absence of lung and heart comorbidity. OBJECTIVES: The aims of this study were to investigate whether OSA patients without any other cardiac or lung disease develop pulmonary hypertension, and to assess the effect of continuous positive airway pressure (CPAP) treatment on pulmonary artery pressure (P(PA)). METHODS: Twenty-nine patients aged 51 +/- 10 years with OSA and 12 control subjects were studied with pulsed-wave Doppler echocardiography for estimation of P(PA) before and after 6-month effective treatment with CPAP. RESULTS: A significantly higher mean P(PA) was found in OSA patients as compared to control subjects (17.2 +/- 5.2 vs. 12.1 +/- 1.9 mm Hg, p < 0.001). Six out of the 29 OSA patients had mild pulmonary hypertension (P(PA) > or = 20 mm Hg). Significant differences were observed between pulmonary hypertensive and normotensive OSA patients with respect to age (62 +/- 4 vs. 48 +/- 15 years, respectively, p < 0.05), body mass index (41 +/- 7 vs. 32 +/- 4 kg/m(2), p < 0.02) and daytime P(a)O(2) (81 +/- 9 vs. 92 +/- 9 mm Hg, p < 0.05). CPAP treatment was effective in reducing mean P(PA) in both groups of pulmonary hypertensive and normotensive OSA patients (decreases in P(PA) from 25.6 +/- 4.0 to 19.5 +/- 1.5 mm Hg, p < 0.001; from 14.9 +/- 2.2 to 11.5 +/- 2.0 mm Hg, respectively, p < 0.001). CONCLUSIONS: A proportion (20.7%) of OSA patients without any other lung or heart disease and characterized by older age, greater obesity and lower daytime oxygenation develop mild pulmonary hypertension which has been partially or completely reversed after 6-month CPAP treatment. In conclusion, OSA alone constitutes an independent risk factor for the development of pulmonary hypertension.     

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.     

经鼻持续气道正压通气治疗睡眠呼吸暂停综合征的依从性及其影响因素

目的　调查睡眠呼吸暂停综合征 (SAS)患者接受经鼻持续气道正压通气 (nCPAP)治疗的依从性、主观疗效和不良反应 ,了解影响依从性的相关因素。方法　对我院 1994年 2月～ 2 0 0 0年 8月间接受nCPAP治疗的 118例SAS患者进行有关依从性的问卷调查并分析其影响因素。结果　 118例SAS患者中 5 7%应用nCPAP依从性良好 ,影响nCPAP治疗依从性的因素主要有治疗前睡眠呼吸暂停 /低通气指数 (AHI) (P =0 0 35 )、治疗前夜间最低血氧饱和度 (LSaO2 ) (P =0 0 0 6 )、治疗前及后Epworth嗜睡评分 (ESS) (P值均 <0 0 0 1)及CPAP呼吸机的性能 (P <0 0 0 1)。结论　 5 7%的SAS患者能长期坚持应用nCPAP治疗 ,nCPAP可作为SAS长期治疗的重要手段 ;影响nCPAP治疗依从性的因素主要有治疗前AHI、治疗前夜间LSaO2 、治疗前及后ESS及CPAP呼吸机的性能。     

Effects of continuous positive airway pressure treatment and withdrawal in patients with obstructive sleep apnea on arterial stiffness and central BP

BACKGROUND: Obstructive sleep apnea (OSA) is associated with increased BP and other cardiometabolic risk factors. The aim of the present study was to determine whether arterial stiffness and central BP (two important cardiovascular risk factors) would change, independent of peripheral BP following either the initiation of or withdrawal from nasal continuous positive airway pressure (CPAP) treatment in subjects with OSA. METHODS AND RESULTS: Arterial stiffness and peripheral and central BP were measured at baseline, and then either at 2 months after starting CPAP therapy (intervention group, n=20) or 7 nights after withdrawal from CPAP therapy (withdrawal group, n=20) using pulse wave analysis. In the intervention group, there were reductions in arterial stiffness (ie, the aortic augmentation index fell by 2.5%) and central systolic BP (fell by 4.2 mm Hg) without a concomitant reduction in peripheral BP. The change in arterial stiffness was associated with CPAP compliance (r=-0.47). In contrast, in the withdrawal group there were no overall changes in arterial stiffness or BP. However, there was an early morning increase in diastolic BP and heart rate relative to late evening. CONCLUSION: These results suggest that clinically important changes in arterial stiffness and central BP may occur following effective CPAP treatment of OSA without parallel changes in peripheral BP.     

Central sleep apnea reversed by continuous positive airway pressure

Continuous positive airway pressure (CPAP) is an accepted and highly effective method used in the treatment of obstructive sleep apnea (OSA). We have explored the potential utility of CPAP in a patient with sleep apnea without a major contribution of airway obstruction as measured by the usual criteria. The patient showed dramatic clinical and laboratory improvement in central apnea when treated with CPAP. A low level of CPAP (7.5 cm H2O) resulted in the reduction of central apneas from 281 to 32 per night with no significant change in obstructive apneas, which increased from 43 to 59 per night. On a separate night, a higher level of CPAP (12.5 cm H2O) resulted in virtually complete removal of all apneas. Measurement of pharyngeal properties revealed pharyngeal cross-sectional area in the low normal range, but increased pharyngeal compliance. This case illustrates that pharyngeal abnormalities may be present in patients with central sleep apnea, and CPAP may be beneficial in the treatment of this disorder. Although the exact mechanism of action of CPAP in this disorder is unclear, we propose several possibilities that may account for the beneficial effect of CPAP in this patient.     

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.     

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.     

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.     

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.     

持续气道正压通气对阻塞性睡眠呼吸暂停低通气综合征患者能量代谢的影响

目的研究中重度阻塞性睡眠呼吸暂停低通气综合征（0SAHS）患者经鼻面罩持续气道正压通气（CPAP）治疗前后能量代谢的变化特点。方法选取2004年3月至2006年5月在我院睡眠疾患诊治中心就诊的30例中重度OSAHS患者,分别于CPAP治疗前后测量入睡前及非快速眼动（NREM）Ⅰ～Ⅱ期睡眠时静息能量消耗（REE）。同时随机选取我院健康体检中心和我院健康职工其性别、年龄、体质量指数（BMI）均与之相当的30例作为对照组。结果OSAHS组入睡前REE高于对照组F9别为（1823±88）kcal／d、（1537±130）kcal／d],差异有显著性意义（P〈0．01）。与入睡前相比,NREMⅠ～Ⅱ期睡眠时OSAHS组REE明显增高F9别为（1823±88）kcal／d、（3726±650）kcal／d],而对照组[（1434±135）kcal／d]明显降低,差异均有显著性意义（P均〈0．01）。经鼻面罩CPAP治疗后,OSAHS患者入睡前REE降至（1573±130）kcal／d,与治疗前相比差异无显著性意义（P〉0．05）;睡眠时0SAHS组REE降至（2393±456）kcal／d,与治疗前相比差异有显著性意义（P〈0．01）。结论OSAHS患者存在能量代谢异常,经CPAP治疗后其NREMⅠ～Ⅱ期睡眠时REE明显下降。