Respiratory arousals in mild obstructive sleep apnea syndrome.

The objective of the study is to identify patients with mild sleep apnea by counting not only apneas and hypopneas, but also mild respiratory events, which do not fulfill apnea or hypopnea criteria, but result in an arousal (Type-R arousal). Arousals related to body movements (Type-M arousal) were separately counted. The influence of nasal continuous positive airway pressure (nCPAP) on respiratory and movement arousals was analyzed. Daytime sleepiness before and after nCPAP and its relationship to arousal types was investigated using the Multiple Sleep Latency Test (MSLT) and a standardised questionnaire. Twenty-two patients with a mean age of 43.6 +/- 9.2 years underwent polysomnographic evaluation on a baseline night, and during three nights with nCPAP. On the baseline night, subjects presented with a mean RDI of 10.5 +/- 7.2/h, an apnea index (AI) of 1.2 +/- 1.5/h, a hypopnea index (HI) of 9.3 +/- 6.6/h, a R index of 5.2 +/- 5.9/h, and a M index of 9.7 +/- 5.6/h. Use of nCPAP lowered the RDI (p < 0.001) and the R index (p < 0.01). Mean sleep latency in the MSLT increased with nCPAP (p < 0.05) and the patient's subjective well being improved (p < 0.01). Correlation analysis revealed a relationship between Type-R arousals and RDI and HI (r = 0.5, p < 0.01) as well as between questionnaire scores and mean sleep latency. The decrease of Type-R indicates the positive effect of nCPAP. Arousal analysis and detection of mild respiratory events associated with arousals are helpful in investigating the sleep structure and in objectifying clinical symptoms and treatment success in patients with mild OSAS.     

阻塞性睡眠呼吸暂停综合征患者轻度认知功能障碍的MoCA评估

目的 探讨简易精神状态检查量表(MMSE)、蒙特列尔认知评估量表(MoCA)评估阻塞性睡眠呼吸暂停综合征(OSAS)患者轻度认知功能障碍(MCI)的可行性.方法 用便携式多导睡眠仪、MMSE及MoCA对51名OSAS患者和35名单纯鼾症者进行睡眠监测和认知功能的评价.结果 OSAS组MoCA评分结果为21.1 ±3.0,显著低于对照组的25.0 ±2.6(P＜0.01);MMSE评分结果在OSAS组与对照组中分别为27.8±1.8及28.1±1.7,无统计学意义.结论 MoCA对于OSAS患者MCI的早期诊断敏感性优于MMSE,对于MMSE测试结果正常但高度怀疑存在MCI者,MoCA是一种简便可行的筛查工具.     

Brain structural changes in obstructive sleep apnea

STUDY OBJECTIVES: Determine whether obstructive sleep apnea (OSA) subjects show indications of axonal injury. DESIGN: We assessed fiber integrity in OSA and control subjects with diffusion tensor imaging (DTI). We acquired four whole-brain DTI series from each subject. The four series were realigned, and the diffusion tensor calculated at each voxel. Fractional anisotropy (FA), a measure of fiber integrity, was derived from the diffusion tensor, resulting in a whole brain FA "map." The FA maps were spatially normalized, smoothed, and compared using voxel-based statistics to determine differences between OSA and control groups, with age as a covariate (P < 0.05, corrected for multiple comparisons). SETTING: University medical center. SUBJECTS: We studied 41 patients with untreated OSA (mean age +/- SD: 46.3 +/- 8.9 years; female/male: 7/34) with apnea-hypopnea index 15 to 101 (mean +/- SD: 35.7 +/- 18.1 events/hour), and 69 control subjects (mean age +/- SD: 47.5 +/- 8.79 years; female/male: 25/44). MEASUREMENTS AND RESULTS: Multiple regions of lower FA appeared within white matter in the OSA group, and included fibers of the anterior corpus callosum, anterior and posterior cingulate cortex and cingulum bundle, right column of the fornix, portions of the frontal, ventral prefrontal, parietal and insular cortices, bilateral internal capsule, left cerebral peduncle, middle cerebellar peduncle and corticospinal tract, and deep cerebellar nuclei. CONCLUSIONS: White matter is extensively affected in OSA patients; the alterations include axons linking major structures within the limbic system, pons, frontal, temporal and parietal cortices, and projections to and from the cerebellum.     

Palatopharyngoplasty and obstructive sleep apnea syndrome

Thirty-five patients diagnosed with obstructive sleep apnea syndrome (OSAS) underwent palatopharyngoplasty (PPP) after an objective evaluation. They were all monitored polygraphically after surgery. The group's postsurgical results were positive, with significant improvement in the apnea-hypopnea index (A + H index) and oxygen desaturation. However, patients with hypopharyngeal or mandibular problems or massive obesity had poor postsurgical results. As no subject has been followed for longer than two years, the long-term prognosis for this surgical approach is unknown.     

Atrial natriuretic excretion in patients with obstructive sleep apnea syndrome (OSAS)

During obstructive sleep apneas stimuli, that may increase excretion of atrial natriuretic peptide (ANP) occur. The aim of the study was the evaluation whether in patients with OSAS levels of ANP are significantly different in relation to sleep or wakefulness and in relation to disturbances of ventilation during sleep and wakefulness. The material of the study consisted of 34 patients with OSAS (age 25-65 years). There were no differences in the levels of ANP late in the evening, during sleep and early in the morning. There were 2 groups of the patients: with low (< 70 pg/ml, mean at 21 p.m. 9.7 +/- 8.7 pg/ml, at. 2 a.m. 12.5 +/- 9.3 pg/ml, at 6 a.m. 14.4 +/- 15.1 pg/ml) and high (> 70 pg/ml, mean at 21 p.m. 148.6 +/- 232.9 pg/ml, at 2 a.m. 119.5 +/- 45.5 pg/ml, at 6 a.m. 164.9 +/- 161 pg/ml) ANP levels. As compared with patients with low ANP levels, patients with high ANP levels were older and more obese, more frequently had concomitant COPD, lower VC and FEV1, higher daytime PaCO2 and lower PaO2; most of them had peripheral edema. In patients with high ANP levels there was more profound mean arterial blood desaturation during sleep apnoeas than in patients with low ANP levels (SaO2 75 +/- 8% vs 81 +/- 4%, p < 0.001), although apnea index and mean apnea duration were similar in both groups. CONCLUSIONS: In patients with OSAS the daytime and sleep levels of ANP are similar. High levels of ANP can be found in OSAS patients with impaired daytime ventilation and gas exchange, and profound arterial oxygen desaturation during sleep apnoeas.     

Arginase activity and nitric oxide levels in patients with obstructive sleep apnea syndrome

OBJECTIVE:

Obstructive sleep apnea syndrome is characterized by repetitive obstruction of the upper airways, and it is a risk factor for cardiovascular diseases. There have been several studies demonstrating low levels of nitric oxide in patients with obstructive sleep apnea syndrome compared with healthy controls. In this study, we hypothesized that reduced nitric oxide levels would result in high arginase activity. Arginase reacts with L-arginine and produces urea and L-ornithine, whereas L-arginine is a substrate for nitric oxide synthase, which produces nitric oxide.

METHODS:

The study group consisted of 51 obstructive sleep apnea syndrome patients (M/F: 43/8; mean age 49±10 years of age) and 15 healthy control subjects (M/F: 13/3; mean age 46±14 years of age). Obstructive sleep apnea syndrome patients were divided into two subgroups based on the presence or absence of cardiovascular disease. Nitric oxide levels and arginase activity were measured via an enzyme-linked immunosorbent assay of serum samples.

RESULTS:

Serum nitric oxide levels in the control subjects were higher than in the obstructive sleep apnea patients with and without cardiovascular diseases (p<0.05). Arginase activity was significantly higher (p<0.01) in obstructive sleep apnea syndrome patients without cardiovascular diseases compared with the control group. Obstructive sleep apnea syndrome patients with cardiovascular diseases had higher arginase activity than the controls (p<0.001) and the obstructive sleep apnea syndrome patients without cardiovascular diseases (p<0.05).

CONCLUSION:

Low nitric oxide levels are associated with high arginase activity. The mechanism of nitric oxide depletion in sleep apnea patients suggests that increased arginase activity might reduce the substrate availability of nitric oxide synthase and thus could reduce nitric oxide levels.     

Periodic leg movements in patients with obstructive sleep apnea syndrome during nCPAP therapy

Summary Excessive daytime sleepiness and concentration deficits are complained by patients with obstructive sleep apnea syndrome (OSAS) as well as by patients with periodic leg movements (PLM). PLM observed during nCPAP (nasal continuous airways pressure) therapy may therefore cause persistent complaints of diurnal symptoms despite sufficient treatment. 65 OSAS-patients (58 men, 7 women, aged 55.6 ± 8.0 years) were investigated before starting and after the first two nights of nCPAP therapy. Apnea/Hypopnea index decreased in all patients (28.8 ± 18.4/h to 11.5 ± 13.0/h, p ≤ 0.01). 26 patients had an initial PLM index > 5/­h which decreased during treatment (14.6 ± 6.4/h to 10.7 ± 7.8/h) with significant increase of sleep stages 3 and 4. In 22 patients with PLM index < 5/h index increased during therapy (2.7 ± 1.2 to 5.6 ± 7.7/h, p ≤ 0.01). 17 patients developed PLM for the first time during nCPAP-therapy (10.9 ± 3.2 PLM/h). Optimizing of nCPAP therapy did not change PLM frequency. Though the pathogenesis and daytime consequences of PLM in OSAS are not fully proved yet our study may entail different therapeutic approaches. In patients with a decrease of PLM during CPAP-therapy movements seemed at least partially induced by OSAS and CPAP may be the sufficient treatment. In the majority of our cases PLM was demasked during nCPAP therapy thus indicating an independent coexistence of periodic limb movement disorder and OSAS. These patients may profit from a treatment similar to the one in restless legs syndrome when daytime symptoms persist during CPAP therapy.     

Rapid maxillary expansion in children with obstructive sleep apnea syndrome

OBJECTIVE: To evaluate the effect of rapid maxillary expansion on children with nasal breathing and obstructive sleep apnea syndrome. METHOD: Recruitment of children with maxillary contraction, without of adenoid hypertrophy, with a body mass index < 24 kg/m2, with obstructive sleep apnea syndrome demonstrated by polysomnography, and whose parents signed informed consent. Otolaryngologic and orthognathic-odontologic evaluation with clinical evaluation, anterior rhinometry and nasal fibroscopy, panoramic radiographs, anteroposterior and laterolateral telecephalometry were performed at entry and follow-up. Intervention: Rapid maxillary expansion (ie, active phase of treatment) was performed for 10 to 20 days; maintenance of device (for consolidation) and orthodontic treatment on teeth lasted 6 to 12 months. RESULTS: 31 children (19 boys), mean age 8.7 years, participated in the study. The mean apnea-hypopnea index was 12.2 events per hour. At the 4-month follow-up, the anterior rhinometry was normal, and all children had an apnea-hypopnea index < 1 event per hour. The mean cross-sectional expansion of the maxilla was 4.32 +/- 0.7 mm. There was a mean increase of the pyriform opening of 1.3 +/- 0.3 mm. CONCLUSION: Rapid maxillary expansion may be a useful approach in dealing with abnormal breathing during sleep.     

Cardiovascular risk among adults with obstructive sleep apnea syndrome

Cardiovascular diseases and sleep-disordered breathing have been recognized as a public health problem in Mexico and worldwide. These two groups of disorders are closely associated and the evidence accumulated over the last 25 years indicates that obstructive sleep apnea syndrome (OSAS) is an independent risk factor in systemic arterial hypertension, coronary artery disease and stroke. Other associations have also been described, linking these disorders with pulmonary hypertension, cardiac arrhythmias, sudden death during sleep and congestive heart failure. Treatment with continuous positive airway pressure in patients with OSAS has proven to be an efficient primary and secondary cardiovascular prevention strategy. This article reviews the epidemiological evidence that links OSAS with increased cardiovascular risk, and proposes strategies designed to address this growing health problem.     

Vigilance in patients with obstructive sleep apnea and surgical patients

Aim

The Marburg vigilance test (VigiMar) is a vigilance task implemented as a four-choice reaction time task with long duration and low stimulus rate. It tests readiness for reaction under monotonous conditions characterized by sensory deprivation. This study was conducted to compare test results of subjects without sleep disorders to those of patients with untreated obstructive sleep apnea (OSA). In addition, whether patients treated for OSA by continuous positive airway pressure (CPAP) exhibited improvements in vigilance testing and whether subjects without sleep disorders have stable test results in a retest after 2 days were investigated. As test results are given for test thirds separately, these were used to determine whether there was a time-on-task effect for patients with untreated OSA and to check for internal consistency of the VigiMar test.

Patients and methods

A total of 20 patients with OSA and 20 surgical patients (knee arthroscopy) between 25 and 65 years of age were included. All patients were male. Vigilance testing was performed on the day before CPAP treatment was started or on the day before arthroscopy and 2 days later after the second CPAP night or on the first day after the surgical procedure, respectively.

Results

In the baseline vigilance test, reaction times of OSA patients were longer than those of surgical patients, especially during the last third of the test. After 2 nights CPAP, reaction times of OSA patients improved to the same level as those of surgical patients who exhibited homogenous results in baseline and postintervention testing.

Conclusion

The VigiMar test is suitable for the assessment of impaired vigilance. Its internal consistency is high, retest reliability is satisfactory, and it is sensitive for changes in vigilance after only 2 nights CPAP treatment.     

Autonomic cardiovascular tests in children with obstructive sleep apnea syndrome

Study Objectives:

The aim of our study was to investigate cardiovascular autonomic activity during wakefulness, using cardiovascular tests, in a population of children with OSAS.

Design:

Prospective study.

Setting:

Sleep unit of an academic center.

Participants:

We included 25 children (mean age 10.2 ± 2.3 years) undergoing a diagnostic assessment for OSAS, and 25 age-matched healthy control subjects. All subjects underwent an overnight polysomnography and autonomic cardiovascular tests using parts of the Ewing test battery, which is a physiological test used for the assessment of autonomic function (head-up tilt test, Valsalva maneuver, deep breathing test).

Measurements and Results:

Eighteen of 25 children with OSAS (11 males, mean age 9.4 ± 1.7 years) concluded the study. OSAS patients had higher systolic blood pressure, diastolic blood pressure, baseline heart rate, the 30:15 index (which represents the RR interval at the 15th and 30th beats during the head up tilt test), and delta diastolic and systolic blood pressure during the head-up tilt test, while the heart rate variability during the deep breathing test was lower, compared with controls. A positive correlation between systolic and diastolic blood pressure and the apnea-hypopnea index (AHI), and negative between AHI and both the 30:15 index and Valsalva ratio, were found. Stepwise linear regression analysis detected a negative correlation between AHI and the 30:15 index and Valsalva ratio, a positive correlation between overnight mean oxygen saturation and delta heart rate, and between AHI and delta systolic blood pressure.

Conclusions:

Our data point to an increase in basal sympathetic activity during wakefulness and to an impaired reaction to several physiological stimuli, which is dependent on the severity of OSAS.

Citation:

Montesano M; Miano S; Paolino MC; Massolo AC; Ianniello F; Forlani M; Villa MP. Autonomic cardiovascular tests in children with obstructive sleep apnea syndrome. SLEEP 2010;33(10):1349-1355.     

Mandibular advancement and obstructive sleep apnea syndrome

A surgical procedure performed to advance the mandible in patients with retrognathia and obstructive sleep apnea is described. The case history of an obese patient with severe sleep apnea problems who underwent a number of treatments, responding only to mandibular advancement, is presented.     

Cardiopulmonary exercise testing in obstructive sleep apnea syndrome

To investigate whether cardiac dysfunction or abnormal measurements on cardiopulmonary exercise testing (CPET) are present in patients with obstructive sleep apnea syndrome (OSAS) and what factors are responsible for exercise limitation in these patients. We enrolled 20 patients with moderate or severe OSAS in the OSA group and 20 subjects without OSAS in the control group. All subjects underwent a sleep study and cardiac evaluation by radionuclide scanning and CPET. There was no difference in left ventricular ejection fraction (VEF) between the two groups, but the OSA group had a lower right VEF. Patients in the OSA group had a lower VO2(peak), VO2(peak/kg) and workpeak than the control group. The OSA group had a higher breathing reserve and a greater decrease in anaerobic threshold (AT) and oxygen pulse. In conclusion, patients with moderate to severe OSAS had abnormal CPET results. These abnormalities may be due to cardiac disease, pulmonary vascular disease, or possible lack of fitness.