Effects of long-term nasal continuous positive airway pressure on C-reactive protein in patients with obstructive sleep apnea syndrome

Serum levels of C-reactive protein (CRP) were measured in 96 consecutive patients with obstructive sleep apnea syndrome (OSAS) before and after nasal continous positive airway pressure treatment. CRP levels only displayed significant correlations with body mass index (BMI) before treatment. No significant changes were observed in BMI and CRP levels after 9 months of treatment. These data suggest that CRP levels in patients with OSAS may be associated with obesity rather than OSAS itself.     

Renal function in patients with obstructive sleep apnea. Effects of nasal continuous positive airway pressure

Patients with obstructive sleep apnea (OSA) often exhibit nocturnal polyuria, which disappears with nasal continuous positive airway pressure (CPAP) treatment. We measured water and electrolyte urinary excretion, creatinine and osmolal clearances, and water transport during sleep in 13 polygraphically monitored patients with OSA during two consecutive nights, either untreated or treated with nasal CPAP, and in eight normal subjects. Untreated patients with OSA had greater urinary flows and greater urinary sodium, chloride, and potassium excretions than did controls. Nasal CPAP treatment in patients with OSA resulted in a reduction in urinary flow and in sodium and chloride excretion, with a concomitant increase in sodium resorption. None of these effects was observed in CPAP-treated normal subjects. The only effect of nasal CPAP common to normal subjects and patients was a trend toward decreased glomerular filtration rate.     

Neuropsychologic symptoms in obstructive sleep apnea improve after treatment with nasal continuous positive airway pressure

To describe the affective changes associated with sleep restoration we assessed psychologic symptoms using the Profile of Mood States questionnaire before and two months after treatment with nasal continuous positive airway pressure (NCPAP) in seven men with obstructive sleep apnea (OSA). The results were compared with those of a control group of patients with OSA who did not receive NCPAP. Two of six mood factors, depression and fatigue, improved significantly following treatment with NCPAP. Total Mood Disturbance (TMD) score was used to assess global mood differences. The mean TMD score for the patients before treatment was 1.7 and during treatment decreased to -7.6 (p less than 0.05). This mean decrease of 9.3 in the TMD score implies generalized improvement in mood. These findings support the opinion that sleep fragmentation and abnormalities of respiration during sleep are at least partially responsible for affective changes seen in sleep apnea. These psychologic disturbances improve after treatment with NCPAP.     

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.     

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.     

Left ventricular hypertrophy is a common echocardiographic abnormality in severe obstructive sleep apnea and reverses with nasal continuous positive airway pressure

STUDY OBJECTIVES: To determine cardiac structural abnormalities by echocardiography in subjects with severe obstructive sleep apnea (OSA), and to determine the long-term effects of nasal continuous positive airway pressure (CPAP) on such abnormalities. DESIGN: Polysomnography was conducted on oximetry-screened patients who showed a desaturation index > 40/h and > or = 20% cumulative time spent below 90%. From these, 25 patients with severe OSA but without daytime hypoxemia underwent echocardiography prior to, then 1 month and 6 months following initiation of CPAP treatment. SETTING: Outpatient sleep disorders center. RESULTS: Of the 25 patients, 13 patients (52%) had hypertension by history or on physical examination. Baseline echocardiograms showed that severe OSA was associated with numerous cardiovascular abnormalities, including left ventricular hypertrophy (LVH) [88%], left atrial enlargement (LAE) [64%], right atrial enlargement (RAE) [48%], and right ventricular hypertrophy (16%). In all patients (intent to treat) as well as those patients compliant with CPAP therapy (84% > 3 h nightly), there was a significant reduction in LVH after 6 months of CPAP therapy as measured by interventricular septal distance (baseline diastolic mean, 13.0 mm; 6-month mean after CPAP, 12.3 mm; p < 0.02). RAE and LAE were unchanged after CPAP therapy. CONCLUSIONS: LVH was present in high frequency in subjects with severe OSA and regressed after 6 months of nasal CPAP therapy.     

Left ventricular function in patients with obstructive sleep apnoea syndrome before and after treatment with nasal continuous positive airway pressure

BACKGROUND: Previous studies have yielded disparate results regarding the effect of obstructive sleep apnoea (OSA) syndrome on left ventricular (LV) function. OBJECTIVES: In order to clarify this, we performed a prospective study investigating OSA patients with no history of systemic hypertension, coronary artery disease, myocardial, pericardial or valvular problems, asthma or chronic obstructive pulmonary disease before and after treatment with nasal continuous positive airway pressure (nCPAP). METHODS: Fifteen patients (3 women, 12 men) with an apnoea/hypopnoea index >15 (mean +/- SD = 52 +/- 21) were studied with complete polysomnography, ambulatory blood pressure monitoring, M-mode two-dimensional echocardiography and pulsed Doppler echocardiography in two phases, i.e. before and after 12-14 weeks of nCPAP therapy. We measured systolic and diastolic blood pressure (BP) separately in the daytime and night-time, isovolumic relaxation time (IVRT), the ratio of peak early filling velocity (E) to peak late velocity (A) diastolic transmitral flow (E/A), posterior wall thickness (PWT) and septal thickness (IVST). The shortening fraction (SF) was also calculated. Eleven overweight non-apnoeic normal subjects matched for age were used as the control group. RESULTS: Our results showed that the patient group exhibited, before treatment, LV diastolic, but not systolic, dysfunction compared with the normal group (IVRT = 94.3 +/- 11.6 ms, p < 0.05; E/A = 0.94 +/- 0.26, p < 0.02; SF = 39.9 +/- 4.1%, not significant (NS); IVST = 9.9 +/- 1.2 mm, NS; PWT = 8.3 +/- 1.2 mm, NS). Moreover, the patient group developed diastolic hypertension both in the daytime and night-time (BP/diastolic/daytime = 93.3 +/- 9.2 mm Hg, BP/diastolic/night-time = 90.3 +/- 10.7 mm Hg). After 12-14 weeks of nCPAP treatment (no change in body mass index), significant improvement in LV diastolic function and a drop in blood pressure were noticed (IVRT = 85.6 +/- 8.8 ms, p < 0.05; E/A = 1.07 +/- 0.3, p < 0.05; BP/diastolic/daytime = 86.3 +/- 5.5 mm Hg, p < 0.02; BP/diastolic/night-time = 83.9 +/- 8. 6 mm Hg, p < 0.05) in our patient group. CONCLUSIONS: We conclude that repetitive apnoeas/hypopnoeas are very important factors in the development of both LV diastolic dysfunction and diastolic systemic hypertension in patients with OSA syndrome. Treatment with nCPAP leads to significant improvement in both ventricular function and systemic hypertension.     

Changes in cerebral hemoglobin indices in obstructive sleep apnea syndrome with nasal continuous positive airway pressure treatment

Introduction  

This study examined both the relationship between the changes in the brain tissue hemoglobin indices and SpO₂ during sleep in patients with obstructive sleep apnea syndrome (OSAS) and the effect of nasal continuous positive airway pressure (CPAP) treatment on hemoglobin indices.     

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.     

持续气道正压通气对阻塞性睡眠呼吸暂停患者睡眠结构的影响

目的探讨患者白天嗜睡等症状的原因,评估经鼻持续气道内正压通气(nCRAP)治疗对阻塞性睡眠呼吸暂停患者睡眠结构的影响。方法选择2001-2004年广东省佛山市第一人民医院呼吸科34例OSAS病人在睡眠多导生理记录仪监测下,进行nCPAP治疗,观察治疗前后呼吸紊乱指数、血氧饱和度和睡眠结构的变化。结果治疗后呼吸紊乱指数下降,最低血氧饱和度上升,睡眠结构明显改善。结论nCRAP能有效地改善OSAS病人的睡眠结构和呼吸紊乱。     

经鼻持续正压通气治疗夜间心绞痛合并阻塞性睡眠呼吸暂停低通气综合征

目的 探讨阻塞性睡眠呼吸暂停低通气综合征（OSAHS）和夜间心绞痛的关系以及经鼻持续正压通气治疗能否改善合并有OSAHS患者夜间心绞痛发作。方法 采用多导睡眠监测系统对46例夜间心绞痛患者进行整夜监测，对合并OSAHS的患者应用经鼻持续正压通气治疗，将患者治疗前后多导睡眠监测参数进行对照研究。结果 夜间心绞痛合并OSAHS的患者经持续正压通气治疗多导睡眠参数明显改善，治疗前后对比差异有显著性，心绞痛症状明显改善。结论 OSAHS和夜间心绞痛有相关性，OSAHS是夜间心绞痛发作的诱因。经鼻持续正压通气治疗可改善合并有0SAHS患者夜间心绞痛发作。     

Falls in blood pressure in patients with obstructive sleep apnoea after long-term nasal continuous positive airway pressure treatment

OBJECTIVES: Effective treatment of obstructive sleep apnoea (OSA) with nasal continuous positive airway pressure (nCPAP) lowers blood pressure (BP). The long-term effects of nCPAP treatment on BP in OSA patients are not well known. The time period of such treatment sufficient to lower BP in OSA patients is also not known. We investigated compliance with long-term nCPAP therapy and its effects on BP. METHODS: This observational study involved 66 OSA patients [59 men, seven women; mean age, 51 (48-54) years; body mass index (BMI), 28.7 (27.7-29.7) kg/m; apnoea and hypopnoea, 50.3 (45.6-55.0)/h; 95% confidence intervals]. BP and BMI were measured before the study and at two checkpoints after usage of nCPAP [620 (552-688) and 1071 (1000-1143) days]. RESULTS: The different times between the first and second checkpoints for detecting objective compliance were 17 (4-30) min (P = 0.003). Diastolic BP decreased by 5.9 (3.1-8.7) mmHg after 600 days nCPAP treatment and by 4.6 (2.0-7.2) mmHg after 1000 days (P = 0.0006). Systolic BP and BMI did not change significantly. Usage of nCPAP treatment for a daily average of 3 h was needed to achieve a significant decrease in diastolic BP [7.4 (4.3-10.6) mmHg, P < 0.0001]. Diastolic BP of normotensive OSA patients did not change significantly by nCPAP treatment, but that of hypertensive OSA patients decreased significantly within 1 month-3 years of nCPAP treatment whether or not medication was used. CONCLUSIONS: In patients with severe OSA, the use of nCPAP for a daily average of 3 h would be sufficient to decrease the diastolic BP of hypertensive OSA patients.     

经鼻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睡眠结构近远期的影响

目的　观察经鼻持续气道正压 (nCPAP)通气对阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者睡眠结构近远期的影响。方法　 17例对照者行多导睡眠图 (PSG)监测 ,对 30例经PSG诊断的OSAHS患者行nCPAP治疗 ,治疗第 1夜行PSG监测 ,连续家庭nCPAP治疗 6个月后行第 2次PSG监测 ,分析比较睡眠结构的变化。结果　OSAHS患者治疗前睡眠转换次数、1期、2期睡眠比例较对照组增加 (P <0 0 5 ) ,慢波睡眠期、快动眼 (REM )期比例较对照组低 (P <0 0 5 ) ;nCPAP治疗第 1夜睡眠转换次数、1期、2期睡眠比例较治疗前降低 (P <0 0 5 ) ,慢波睡眠期、REM期比例较治疗前升高 (P <0 0 5 ) ;nCPAP治疗 6个月后睡眠转换次数、1期、2期、慢波睡眠期比例与治疗第 1夜比较差异均无显著性 (P >0 0 5 ) ,而REM期比例较治疗第 1夜降低 (P <0 0 5 )。结论　OSAHS患者睡眠转换次数明显增多 ,1期睡眠增加而REM期睡眠减少 ,睡眠结构紊乱。nCPAP治疗第 1夜及6个月后睡眠结构得到有效纠正 ,是OSAHS长期有效的治疗方法之一。     

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.     

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.