Reverse atrial electrical remodelling induced by continuous positive airway pressure in patients with severe obstructive sleep apnoea

Background

Obstructive sleep apnoea (OSA) is associated with cardiovascular morbidity and mortality, including atrial arrhythmias. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA; its impact on atrial electrical remodelling has not been fully investigated. Signal-averaged p-wave (SAPW) duration is an accepted marker for atrial electrical remodelling.

Objective

The objective of this study is to determine whether CPAP induces reverse atrial electrical remodelling in patients with severe OSA.

Methods

Consecutive patients attending the Sleep Disorder Clinic at Kingston General Hospital underwent full polysomnography. OSA-negative controls and severe OSA were defined as apnoea–hypopnea index (AHI)?<?5 events/hour and AHI?≥?30 events/hour, respectively. SAPW duration was determined at baseline and after 4–6 weeks of CPAP in severe OSA patients or without intervention controls.

Results

Nineteen severe OSA patients and 10 controls were included in the analysis. Mean AHI and minimum oxygen saturation were 41.4?±?10.1 events/hour and 80.5?±?6.5 % in severe OSA patients and 2.8?±?1.2 events/hour and 91.4?±?2.1 % in controls. At baseline, severe OSA patients had a greater SAPW duration than controls (131.9?±?10.4 vs 122.8?±?10.5 ms; p?=?0.02). After CPAP, there was a significant reduction of SAPW duration in severe OSA patients (131.9?±?10.4 to 126.2?±?8.8 ms; p?<?0.001), while SAPW duration did not change after 4–6 weeks in controls.

Conclusion

CPAP induced reverse atrial electrical remodelling in patients with severe OSA as represented by a significant reduction in SAPW duration.     

Gender differences in the polysomnographic features of obstructive sleep apnea

We examined the influence of gender on the polysomnographic features of obstructive sleep apnea (OSA) in a retrospective study of 830 patients with OSA diagnosed by overnight polysomnography (PSG). The severity of OSA was determined from the apnea- hypopnea index (AHI) for total sleep time (AHI(TST)), and was classified as mild (5 to 25 events/h), moderate (26 to 50 events/h), and severe (> 50/events/h). Differences in OSA during different stages of sleep were assessed by comparing the AHI during non-rapid eye movement (NREM) (AHI(NREM)) and rapid eye movement (REM) (AHI(REM)) sleep and calculating the "REM difference" (AHI(REM) - AHI(NREM)). Additionally, each overnight polysomnographic study was classified as showing one of three mutually exclusive types of OSA: (1) mild OSA, which occurred predominantly during REM sleep (REM OSA); (2) OSA of any severity, which occurred predominantly in the supine position (S OSA); or (3) OSA without a predominance in a single sleep stage or body position (A OSA). The mean AHI(TST) for men was significantly higher than that for women (31.8 +/- 1.0 versus 20.2 +/- 1.5 events/h, p < 0. 001). The male-to-female ratio was 3.2:1 for all OSA patients, and increased from 2.2:1 for patients with mild OSA to 7.9:1 for those with severe OSA. Women had a lower AHI(NREM) than did men (14.6 +/- 1.6 versus 29.6 +/- 1.1 events/h, p < 0.001), but had a similar AHI(REM) (42.7 +/- 1.6 versus 39.9 +/- 1.2 events/h). Women had a significantly higher REM difference than did men (28.1 +/- 1.5 versus 10.3 +/- 1.1 events/h, p < 0.01). REM OSA occurred in 62% of women and 24% of men with OSA. S OSA occurred almost exclusively in men. We conclude that: (1) OSA is less severe in women because of milder OSA during NREM sleep; (2) women have a greater clustering of respiratory events during REM sleep than do men; (3) REM OSA is disproportionately more common in women than in men; and (4) S OSA is disproportionately more common in men than in women. These findings may reflect differences between the sexes in upper airway function during sleep in patients with OSA.     

Treatment of obstructive sleep apnea using a custom-made titratable duobloc oral appliance: a prospective clinical study

Purpose

This prospective clinical study investigates the efficacy of a specific custom-made titratable mandibular advancement device (MAD) for the treatment of obstructive sleep apnea (OSA). This MAD has attachments in the frontal teeth area that allow for progressive titration of the mandible.

Methods

Sixty-one adult OSA patients were included (age, 46.7?±?9.0 years; male/female ratio, 45/16; apnea–hypopnea index (AHI), 23.2?±?15.4 events/h sleep; body mass index, 27.9?±?4.1 kg/m²). After an adaptation period, titration started based on a protocol of symptomatic benefit or upon reaching the physiological limits of protrusion. As a primary outcome, treatment response was defined as an objective reduction in AHI following MAD treatment of ≥50 % compared to baseline, and treatment success as a reduction in AHI with MAD to less than 5 and 10 events/h sleep. Compliance failure was defined as an inability to continue treatment.

Results

A statistically significant decrease was observed in AHI, from 23.4?±?15.7 at baseline to 8.9?±?8.6 events/h with MAD (p?<?0.01). Treatment response was achieved in 42 out of 61 patients (68.8 %), whereas 42.6 % met criteria of AHI?<?5 and 63.9 % achieved an AHI?<?10 events/h sleep, respectively. Four patients (6.6 %) were considered as “compliance failures.”

Conclusions

The present study has evaluated the efficacy of a specific custom-made titratable MAD in terms of sleep apnea reduction.     

Effects of twin block appliance on obstructive sleep apnea in children: a preliminary study

Background

Oral appliances are increasingly advocated as a treatment option for obstructive sleep apnea (OSA). However, it is not clear how the different designs influence treatment efficacy in children. The aim of this study was to investigate the effects of twin block (TB) appliance on children with OSA and mandibular retrognathia.

Methods

A total of 46 children (31 males, 15 females, aged 9.7?±?1.5 years, BMI: 18.1?±?1.04 kg/m²) diagnosed with mandibular retrognathia and OSA by polysomnography (PSG) and with no obesity or adenotonsillar hypertrophy were recruited for the study. Patients in the treatment group were instructed to wear the twin block oral appliance full time for an average of 10.8 months. The efficacy of treatment was determined by monitoring the PSG and cephalometric changes before and after appliance removal. Data were analyzed using paired t test.

Results

Results showed an improvement in patient's facial profile after treatment with the TB appliance. The average AHI index decreased from 14.08?±?4.25 to 3.39?±?1.86 (p?<?0.01), and the lowest SaO₂ increased from 77.78?±?3.38 to 93.63?±?2.66 (p?<?0.01). Cephalometric measurements showed a significant increase in the superior posterior airway space, middle airway space, SNB angle and facial convexity which indicate an enhancement in mandibular growth, and reduction in the soft palate length.

Conclusions

This preliminary study suggests that twin block appliance may improve the patient's facial profile and OSA symptoms in a group of carefully selected children presented with both OSA and mandibular retrognathia symptoms.     

Analysis of anatomical and functional determinants of obstructive sleep apnea

Purpose

Craniofacial abnormalities have an important role in the occurrence of obstructive sleep apnea (OSA) and may be particularly significant in Asian patients, although obesity and functional abnormalities such as reduced lung volume and increased airway resistance also may be important. We conducted simultaneous analyses of their interrelationships to evaluate the relative contributions of obesity, craniofacial structure, pulmonary function, and airway resistance to the severity of Japanese OSA because there are little data in this area.

Methods

A cross-sectional observational study was performed on 134 consecutive Japanese male patients. A sleep study, lateral cephalometry, pulmonary function tests, and impulse oscillometry (IOS) were performed on all patients.

Results

Age, body mass index (BMI), position of the hyoid bone, and proximal airway resistance on IOS (R20) were significantly related to the apnea/hypopnea index (AHI) (p?<?0.05) in multiple regression analysis. Subgroup analysis showed that, for moderate-to-severe OSA (AHI????15 events/h), neck circumference and R20 were predominantly related to AHI, whereas for non-to-mild OSA (AHI?<?15 events/h), age and expiratory reserve volume were the predominant determinants. In obese subjects (BMI????25?kg/m²), alveolar?Carterial oxygen tension difference, position of the hyoid bone, and R20 were significantly associated with AHI, whereas age alone was a significant factor in nonobese subjects (BMI?<?25?kg/m²).

Conclusions

Aside from age and obesity, anatomical and functional abnormalities are significantly related to the severity of Japanese OSA. Predominant determinants of AHI differed depending on the severity of OSA or the magnitude of obesity.     

Subjective sleepiness and daytime functioning in bariatric patients with obstructive sleep apnea

Purpose

The purpose of this study was to evaluate associations between obstructive sleep apnea (OSA) severity and self-reported sleepiness and daytime functioning in patients considering bariatric surgery for treatment of obesity.

Methods

Using a retrospective cohort design, we identified 342 patients who had sleep evaluations prior to bariatric surgery. Our final sample included 269 patients (78.6 % of the original cohort, 239 females; mean age?=?42.0?±?9.5 years; body mass index?=?50.2?±?7.7 kg/m²) who had overnight polysomnography and completed the Epworth Sleepiness Scale (ESS) and the Functional Outcomes of Sleep Questionnaire (FOSQ). Patients' OSA was classified as none/mild (apnea–hypopnea index (AHI)?<?15, n?=?112), moderate (15?≤?AHI?<?30, n?=?77), or severe (AHI?≥?30, n?=?80). We calculated the proportion of unique variance (PUV) for the five FOSQ subscales. ANOVA was used to determine if ESS and FOSQ were associated with OSA severity. Unpaired t tests compared ESS and FOSQ scores in our sample with published data.

Results

The average AHI was 29.5?±?31.5 events per hour (range?=?0–175.8). The mean ESS score was 6.3?±?4.8, and the mean global FOSQ score was 100.3?±?18.2. PUVs for FOSQ subscales showed moderate-to-high unique contributions to FOSQ variance. ESS and global FOSQ score did not differ by AHI group. Only the FOSQ vigilance subscale differed by OSA severity with the severe group reporting more impairment than the moderate and none/mild groups. Our sample reported less sleepiness and daytime impairment than previously reported means in patients and controls.

Conclusions

Subjective sleepiness and functional impairment were not associated significantly with OSA severity in our sample of patients considering surgery for obesity. Further research is needed to understand individual differences in sleepiness in patients with OSA. If bariatric patients underreport symptoms, self-report measures are not an adequate substitute for objective assessment and clinical judgment when evaluating bariatric patients for OSA. Patients with severe obesity need evaluation for OSA even in the absence of subjective complaints.     

Influence of the right- versus left-sided sleeping position on the apnea-hypopnea index in patients with sleep apnea

Purpose

Sleep and sleep position have a significant impact on physical, cardiac and mental health, and have been evaluated in numerous studies particularly in terms of lateral sleeping positions and their association with diseases. We retrospectively examined the relationship between the sleeping position and position-specific apnea-hypopnea index (AHI) in obstructive sleep apnea-hypopnea (OSA) patients.

Methods

We assessed the sleeping body position and the body position-specific AHI score in patients who were referred for suspected OSA and underwent diagnostic nocturnal polysomnography. In order to eliminate inter-individual differences, only those who had a similar percentage of time spent in the LSSP and RSSP for each patient were enrolled. To provide this validity, only subjects that had a similar percentage of left and right lateral sleep time (±10%) were included in the analysis.

Results

A total of 864 patients had nocturnal diagnostic PSG. Of them, 131 patients met the inclusion criteria. The percent rate spent in the supine sleeping position (SSP) was 31.3?±?18.7%, in the LSSP was 31.8?±?10% and in the RSSP was 32.6?±?10.8%. Whereas the SSP-specific AHI score was the highest with 60.4?±?36.2/h among all the sleeping position-specific AHI scores (p?<?0.001), the LSSP-specific AHI score was statistically higher than that for RSSP (30.2?±?32.6/h vs. 23.6?±?30.1/h; p?<?0.001). When comparing individuals sub-grouped based on OSA severity, there was a statistically significant difference between the LSSP-specific AHI score and RSSP-specific AHI score in patients with severe (p?=?0.002) and moderate (p?=?0.026), but not mild (p?=?0.130) OSA.

Conclusion

We found that the sleeping position had a significant influence on apneic events and RSSP decreased the frequency of obstructive respiratory events in patients with moderate and severe disease.     

Cyclic alternating pattern analysis in REM sleep behavior disorder

Objective

Rapid eye movement (REM) sleep behavior disorder (RBD) is a type of REM parasomnia characterized by complex motor activity during REM sleep. In this study, cyclic alternating pattern (CAP) in patients with idiopathic RBD was analyzed to evaluate the expression of arousal instability of NREM sleep.

Methods

A total of 31 idiopathic RBD patients and age- and gender-matched 21 control subjects were consecutively recruited. Conventional sleep polysomnographic recording parameters and CAP parameters were compared between RBD and the control group.

Results

The number of CAP cycles (120.13?±?113.56, p?=?0.007), CAP sequences (20.9?±?18.15, p?<?0.001), CAP index (25.14?±?24.44, p?=?0.017), and CAP rate (24.07?±?13.22, p?=?0.016) were all significantly higher in RBD patients compared to the control group. The increase in CAP sequences was observed in phase A2 and A3 subtypes while phase A1 subtype was significantly lower in RBD patients. A significant positive correlation was observed between disease duration with total CAP time (r?=?0.289, p?=?0.042) and A3 index (r?=?0.32, p?=?0.024). There was a negative correlation between the age and A1 index (r?=??0.4491, p?=?0.0001).

Conclusion

To our knowledge this is the first polysomnographic clinical study which evaluated CAP parameters in RBD. Increased CAP rate found may be considered as a sign showing that NREM sleep may also be affected in RBD patients. Therefore, CAP analysis may be important to enlighten the pathogenesis of parasomnias.     

An electrocardiogram-based analysis evaluating sleep quality in patients with obstructive sleep apnea

Objective

The study compares polysomnography (PSG) and cardiopulmonary coupling (CPC) sleep quality variables in patients with (1) obstructive sleep apnea (OSA) and (2) successful and unsuccessful continuous positive airway pressure (CPAP) response.

Patients/methods

PSGs from 50 subjects (32 F/18 M; mean age 48.4?±?12.29 years; BMI 34.28?±?9.33) were evaluated. OSA patients were grouped by no (n?=?16), mild (n?=?13), and moderate to severe (n?=?20) OSA (apnea–hypopnea index (AHI)?≤?5, >5–15, >15 events/h, respectively). Outcome sleep quality variables were sleep stages in non-rapid eye movement, rapid eye movement sleep, and high (HFC), low (LFC), very low-frequency coupling (VLFC), and elevated LFC broad band (e-LFC_BB). An AHI?≤?5 events/h and HFC?≥?50 % indicated a successful CPAP response. CPC analysis extracts heart rate variability and QRS amplitude change that corresponds to respiration. CPC-generated spectrograms represent sleep dynamics from calculated coherence product and cross-power of both time series datasets.

Results

T tests differentiated no and moderate to severe OSA groups by REM % (p?=?0.003), HFC (p?=?0.007), VLFC (p?=?0.007), and LFC/HFC ratio (p?=?0.038) variables. The successful CPAP therapy group (n?=?16) had more HFC (p?=?0.003), less LFC (p?=?0.003), and e-LFC_BB (p?=?0.029) compared to the unsuccessful CPAP therapy group (n?=?8). PSG sleep quality measures, except the higher arousal index (p?=?0.038) in the unsuccessful CPAP group, did not differ between the successful and unsuccessful CPAP groups. HFC?≥?50 % showed high sensitivity (77.8 %) and specificity (88.9 %) in identifying successful CPAP therapy.

Conclusions

PSG and CPC measures differentiated no from moderate to severe OSA groups and HFC?≥?50 % discriminated successful from unsuccessful CPAP therapy. The HFC?≥?50 % cutoff showed clinical value in identifying sleep quality disturbance among CPAP users.     

Effect of musculoskeletal pain on sleep architecture in patients with obstructive sleep apnea

Rationale

Obstructive sleep apnea and chronic musculoskeletal pain both affect sleep. Sleep architecture of patients suffering from both is largely unknown.

Objectives

This study seeks to define the sleep architecture of patients with chronic musculoskeletal pain and obstructive sleep apnea.

Methods

Patients with obstructive sleep apnea diagnosed by sleep study during the past 3 years were included. Patients with clinical documentation of chronic musculoskeletal pain constituted cases, while others were classified as controls.

Measurements

Demographics, clinical factors affecting sleep, medications affecting sleep, Epworth sleepiness scores, and polysomnographic parameters; total sleep time, sleep efficiency, sleep stages, rapid eye movement (REM) sleep onset, apnea–hypopnea index, arousal index, and periodic leg movements were recorded.

Results

There were 393 subjects: 200 cases (obstructive sleep apnea and chronic musculoskeletal pain) and 193 controls (obstructive sleep apnea alone). There was significant difference in total sleep time (274.5?±?62.5 vs. 302.2?±?60.1 min, p?=?0.0001), sleep efficiency (73.54?±?15.8 vs. 78.76?±?14.3 %, p?=?0.0003), and REM sleep onset (148.18?±?80.5 vs. 124.8?±?70.9 min, p?=?0.006). Subgroup analysis within the obstructive sleep apnea with chronic musculoskeletal pain group revealed that subjects had better total sleep time and sleep efficiency if they were on REM sleep affecting medications (suppressants and stimulants). Those on REM sleep suppressants slept 25.7 min longer and had 6.4 % more efficient sleep than those not on REM suppressants (p?=?0.0034 and p?=?0.0037).

Conclusion

Patients with obstructive sleep apnea and chronic musculoskeletal pain sleep not only significantly less but also with inferior sleep quality. Their REM sleep is also less in duration and its onset is delayed. Despite low TST and SE, these patients may not exhibit sleepiness.     

Complete denture wear during sleep in elderly sleep apnea patients—a preliminary study

Objectives

There is no consensus in the literature about the impact of complete denture wear on obstructive sleep apnea (OSA). The goal of this randomized clinical study was to assess if complete denture wear during sleep interferes with the quality of sleep.

Materials and methods

Elderly edentulous OSA patients from a complete denture clinic were enrolled and received new complete dentures. An objective sleep analysis was determined with polysomnography performed at the sleep laboratory for all patients who slept either with or without their dentures.

Results

Twenty-three patients (74% females) completed the study with a mean age of 69.6?years and a mean body mass index of 26.7?kg/m². The apnea and hypopnea index (AHI) was significantly higher when patients slept with dentures compared to without (25.9?±?14.8/h vs. 19.9?±?10.2/h; p?>?0.005). In the mild OSA group, the AHI was significantly higher when patients slept with the dentures (16.6?±?6.9 vs. 8.9?±?2.4; p?p?=?0.2). The supine AHI in mild patients was related to a higher increase in AHI while wearing dentures (12.7?±?8.4/h vs. 51.9?±?28.6/h; p?Conclusions Contrary to previous studies, we found that OSA patients may experience more apneic events if they sleep with their dentures in place. Specifically, in mild OSAS patients, the use of dentures substantially increases the AHI especially when in the supine position.     

P wave duration and dispersion in Holter electrocardiography of patients with obstructive sleep apnea

Purpose

The underlying mechanisms of the association between obstructive sleep apnea (OSA) and atrial fibrillation (AF) remained unclear. We investigated P wave parameters as indicators of atrial conduction status among OSA patients.

Methods

We studied 42 untreated OSA patients, categorized into mild (6), moderate (18), and severe (18) OSA based on the apnea/hypopnea index (AHI) and 18 healthy controls. Twenty-four-hour Holter electrocardiography was applied to measure P wave parameters including P wave duration and P wave dispersion; difference between the maximum (P-max) and minimum (P-min) measured P wave duration.

Results

Mean P wave duration ranged from 110.2?±?9.3 ms in mild OSA patients to 121.1?±?15.4 ms in severe OSA patients and was 113.4?±?10.0 ms in controls with no significant difference among the groups, P?=?0.281. P wave dispersion and P-max were significantly longer in those with moderate OSA (68.0?±?9.3 and 154.2?±?9.3 ms) and those with severe OSA (71.6?±?13.7 and 157.2?±?13.3 ms) than controls (52.6?±?15.3 and 142.1?±?15.4 ms), P?r?=?0.407, P?=?0.012) and P wave dispersion (r?=?0.431, P?=?0.008). With linear regression analysis controlling for age, gender, and BMI, the AHI was independently associated with P wave dispersion (β?=?0.482, P?=?0.002).

Conclusions

Using Holter monitoring for measurement of P wave parameters, this study showed an association of OSA with prolonged P-max and P wave dispersion. These results indicate that patients with OSA have disturbances in atrial conduction associated with OSA severity. Repeating this study in a larger sample of patients is warranted.     

Oxidative stress and inflammatory markers in the exhaled breath condensate of children with OSA

Introduction

Obstructive sleep apnea (OSA) in children has been associated with systemic inflammation and oxidative stress. Limited evidence indicates that pediatric OSA is associated with oxidative stress and inflammation in the airway.

Objective

The objective of this study is to assess the hypothesis that levels of oxidative stress and inflammatory markers in the exhaled breath condensate (EBC) of children with OSA are higher than those of control subjects.

Methods

Participants were children with OSA and control subjects who underwent overnight polysomnography. Morning levels of hydrogen peroxide (H₂O₂) and sum of nitrite and nitrate (NO _x ) in EBC of participants were measured.

Results

Twelve subjects with moderate-to-severe OSA (mean age?±?standard deviation: 6.3?±?1.7?years; apnea?Chypopnea index??AHI, 13.6?±?10.1 episodes/h), 22 subjects with mild OSA (6.7?±?2.1?years; AHI, 2.8?±?1 episodes/h) and 16 control participants (7.7?±?2.4?years; AHI, 0.6?±?0.3 episodes/h) were recruited. Children with moderate-to severe OSA had higher log-transformed H₂O₂ concentrations in EBC compared to subjects with mild OSA, or to control participants: 0.4?±?1.1 versus ?0.9?±?1.3 (p?=?0.015), or versus ?1.2?±?1.2 (p?=?0.003), respectively. AHI and % sleep time with oxygen saturation of hemoglobin <95% were significant predictors of log-transformed H₂O₂ after adjustment by age and body mass index z score (p? x levels.

Conclusions

Children with moderate-to-severe OSA have increased H₂O₂ levels in morning EBC, an indirect index of altered redox status in the respiratory tract.     

The impact of sleep duration in obstructive sleep apnea patients

Purpose

Obstructive sleep apnea (OSA) is a risk factor for cardiovascular disease. Strong associations have been reported among sleep duration, hypertension, obesity, and cardiovascular mortality. The authors hypothesize that sleep duration may play a role in OSA severity. The aim of this study is to analyze sleep duration in OSA patients.

Methods

Patients who underwent overnight polysomnography were consecutively selected from the Sleep Clinic of Universidade Federal de São Paulo database between March 2009 and December 2010. All subjects were asked to come to the Sleep Clinic at 8:00 a.m. for a clinical evaluation and actigraphy. Anthropometric parameters such as weight, height, hip circumference, abdominal circumference, and neck circumference were also measured.

Results

One hundred thirty-three patients were divided into four groups based on total sleep time, sleep efficiency, sleep latency, and wake after sleep onset: very short sleepers (n?=?11), short sleepers (n?=?21), intermediate sleepers (n?=?56), and sufficient sleepers (n?=?45). Apnea–hypopnea index (AHI) was higher in very short sleepers (50.18?±?30.86 events/h) compared with intermediate sleepers (20.36?±?14.68 events/h; p?=?0.007) and sufficient sleepers (23.21?±?20.45 events/h; p?=?0.02). Minimal and mean arterial oxygen saturation and time spent below 90 % oxygen saturation exhibited worse values in very short sleepers. After adjustment for gender, age, AHI, and body mass index, mean oxygen saturation was significantly associated to total sleep time (p?=?0.01).

Conclusions

In conclusion, the present study suggests that sleep duration may be associated to low mean oxygen saturation in OSA patients.     

Energy expenditure in obstructive sleep apnea: validation of a multiple physiological sensor for determination of sleep and wake

Purpose

Obstructive sleep apnea (OSA) may be associated with increased energy expenditure (EE) during sleep. As actigraphy is inaccurate at estimating EE from body movement counts alone, we aimed to compare a multiple physiological sensor with polysomnography for determination of sleep and wake, and to test the hypothesis that OSA is associated with increased EE during sleep.

Methods

We studied 50 adults referred for routine overnight polysomnography. In addition to polysomnography, the SenseWear Pro3 Armband^TM (Bodymedia Inc.) was placed on the upper right arm. Epoch-by-epoch agreement rate between the measures of sleep versus wake was calculated. Linear regression analyses were performed for EE against apnea–hypopnea index (AHI), 3% oxygen desaturation index (ODI), body mass index (BMI), waist–hip ratio (WHR), gender, age, and average heart rate during sleep.

Results

The epoch-by-epoch agreement rate was high (79.9?±?1.6%) and the ability of the SenseWear to estimate sleep was very good (sensitivity, 88.7?±?1.5%). However, it was less accurate in determining wake (specificity 49.9?±?3.6%). Sleep EE was associated with AHI, 3% ODI, BMI, WHR, and male gender (p?<?0.001 for all). Stepwise multiple linear regression however revealed that BMI, male gender, age, and average heart rate during sleep were independent predictors of EE (Model R ²?=?0.78).

Conclusions

The SenseWear armband provides a reasonable estimation of sleep but a poor estimation of wake. Furthermore, in a selected population of OSA patients, increasing OSA severity is associated with increased EE during sleep, although primarily through an association with increased BMI. However, as our data are not adjusted for fat-free mass and the SenseWear has yet to be validated for EE in OSA patients, these data should be interpreted with caution.     

Obstructive sleep apnea is common in patients with interstitial lung disease

Purpose

The incidence of obstructive sleep apnea (OSA) in interstitial lung disease (ILD) has been reported at different frequencies in several studies. The aims of our study were to evaluate the frequency of OSA in ILD and to analyze the relationship between polysomnography (PSG) findings and pulmonary function, disease severity, parenchymal involvement, and Epworth Sleepiness Scale (ESS) scores.

Methods

ILD patients with parenchymal involvement were evaluated. The disease severity was assessed using an index consisting of body mass index (BMI), carbon monoxide diffusion capacity, the Modified Medical Research Council dyspnea scale, and the 6-min walking distance. All of the patients had lung function, chest X-ray, PSG, ESS scoring, and an upper airway examination. Patients with a BMI?≥?30 or significant upper airway pathologies were excluded.

Results

Of 62 patients, 50 patients comprised the study group (14 male, 36 female; mean age 54?±?12.35 years, mean BMI 25.9?±?3.44 kg/m²) with diagnoses of idiopathic pulmonary fibrosis (IPF; n?=?17), stage II–III sarcoidosis (n?=?15), or scleroderma (n?=?18). The frequency of OSA was 68 %. The mean apnea–hypopnea index (AHI) was 11.4?±?12.5. OSA was more common in IPF patients (p?=?0.009). The frequency of rapid eye movement-related sleep apnea was 52.9 %. The frequency of OSA was higher in patients with a disease severity index ≥3 (p?=?0.04). The oxygen desaturation index and the AHI were higher in patients with diffuse radiological involvement (p?=?0.007 and p?=?0.043, respectively).

Conclusions

OSA is common in ILD. PSG or at minimum nocturnal oximetry should be performed, particularly in patients with functionally and radiologically severe disease.     

Nasal versus oronasal continuous positive airway pressure masks for obstructive sleep apnea: a pilot investigation of pressure requirement, residual disease, and leak

Purpose

This single-blinded, randomized, controlled pilot study aimed to investigate whether there is a difference between nasal and oronasal masks in therapeutic continuous positive airway pressure (CPAP) requirement, residual disease, or leak when treating obstructive sleep apnea (OSA) and if differences were related to measures of upper airway size.

Methods

Patients with severe OSA currently using CPAP at ??4?h/night with a nasal mask were examined (including Mallampati scale, incisal relationship, and mandibular protrusion) and then randomized to receive auto-positive airway pressure (PAP) or fixed CPAP at a manually titrated pressure for 1?week each at home, with immediate crossover. Within each week, a nasal mask and two oronasal masks were to be used for two or three nights each in random order. Data were downloaded from the device.

Results

Twelve patients completed the trial (mean ± SD AHI 59.8?±?28.6 events/h; CPAP 11.1?±?3.2?cmH₂O; BMI 37.7?±?5.0?kg/m²). During auto-PAP, the median 95th percentile pressure delivered with all masks was within 0.5?cmH₂O (p?>?0.05). During CPAP, median residual AHI was 0.61 (IQR?=?1.18) for the nasal mask, 1.70 (IQR?=?4.04) for oronasal mask 1, and 2.48 (IQR?=?3.74) for oronasal mask 2 (p?=?0.03). The 95th percentile leak was lowest with the nasal mask during both CPAP and auto-PAP (both p?Conclusions In obese OSA patients changing from a nasal to oronasal mask increased leak and residual AHI but did not affect the therapeutic pressure requirement. The findings of the current study highlight mask leak as the major difficulty in the use of oronasal masks.     

Mortality in middle-aged men with obstructive sleep apnea in Finland

Introduction

Obstructive sleep apnea (OSA) has been associated with an elevated rate of cardiovascular mortality. However, this issue has not been investigated in patients with elevated proneness to cardiovascular diseases. Our hypothesis was that OSA would have an especially adverse effect on the risk of cardiovascular mortality in Finnish individuals exhibiting elevated proneness for coronary heart diseases.

Methods

Ambulatory polygraphic recordings from 405 men having suspected OSA were retrospectively analyzed. The patients were categorized regarding sleep disordered breathing into a normal group (apnea hypopnea index (AHI)?<?5, n?=?104), mild OSA group (5?≤?AHI?<?15, n?=?100), and moderate to severe OSA group (AHI?≥?15, n?=?201). In addition, basic anthropometric and health data were collected. In patients who died during the follow-up period (at least 12 years and 10 months), the primary and secondary causes of death were recorded.

Results

After adjustment for age, BMI, and smoking, the patients with moderate to severe OSA suffered significantly (p?<?0.05) higher mortality (hazard ratio 3.13) than their counterparts with normal recordings. The overall mortality in the moderate to severe OSA group was 26.4 %, while in the normal group it was 9.7 %. Hazard ratio for cardiovascular mortality was 4.04 in the moderate to severe OSA and 1.87 in the mild OSA group.

Conclusions

OSA seems to have an especially adverse effect on the cardiovascular mortality of patients with an elevated genetic susceptibility to coronary heart diseases. When considering that all our patients had possibility of continuous positive airway pressure treatment and our reference group consisted of patients suffering from daytime somnolence, the hazard ratio of 4.04 for cardiovascular mortality in patients with moderate to severe disease is disturbingly high.     

Comparison of three actigraphic algorithms used to evaluate sleep in patients with obstructive sleep apnea

Purpose

Actigraphy is a non-invasive and valid method to detect sleep/wake status. However, the technique lacks reliability in patients with sleep-disordered breathing and its results may depend on the algorithm employed.

Methods

We compared three currently used algorithms (the Cole-Kripke, Sadeh, and University of California San Diego [UCSD]) and determined which is the most reliable in patients with obstructive sleep apnea (OSA) assessing total sleep time. After identification of the most reliable algorithm, we compared total sleep time with the severity of obstructive sleep apnea.

Results

The mean total sleep time was not significantly different from that yielded by polysomnography when the UCSD algorithm was employed (p?=?0.798) and UCSD algorithm was associated with the smallest bias. The correlation levels (with polysomnographic data) were mild-to-modest when the results yielded by all algorithms were evaluated, but were highest when the UCSD algorithm was employed (UCSD, r?=?0.498, p?<?0.001; Cole-Kripke, r?=?0.389, p?<?0.01; Sadeh, r?=?0.272, p?=?0.057). Actigraphic measures of mean total sleep time underestimated sleep in patients with severe obstructive sleep apnea (apnea–hypopnea index [AHI] ≥30), and the correlation was low (r?=?0.317, p?=?0.116), but overestimated sleep, with high correlations, in patients with mild (5?≤?AHI?<?15) and moderate OSA (15?≤?AHI?<?30; r?=?0.859, p?<?0.001; r?=?0.842, p?<?0.001, respectively).

Conclusions

Among the three actigraphic algorithms tested in this study, sleep duration estimated by the UCSD algorithm was the most correlated with polysomnography data in an OSA population. However, none of them was reliable enough for estimating sleep time in patients with sleep-disordered breathing, especially in patients with severe OSA.     

Levels of thioredoxin are related to the severity of obstructive sleep apnea: based on oxidative stress concept

Background

Oxidative stress is a typical feature of obstructive sleep apnea (OSA). Thioredoxin (TRX), as one of the oxidative stress biomarkers, is a potent protein disulfide reductase in antioxidant defense. Our study is designed to test whether thioredoxin could assess the severity of OSA.

Methods

Sixty-three adults suspected of having OSA were included in this study and were divided into four groups based on the results of polysomnography (PSG): control, mild, moderate, and severe. Subjects with chronic medical diseases (with the exception of essential hypertension) or taking any antioxidant medication were excluded. Blood samples were obtained within an hour after the overnight PSG test. Plasma TRX levels were detected by enzyme-linked immunosorbent assay.

Results

The plasma TRX level in severe group was obviously increased (8.62?±?2.14, 13.33?±?5.60, 14.71?±?5.53, and 16.10?±?7.34 ng/ml; p?<?0.05). The TRX positively related to AHI (r?=?0.313; p?<?0.05), while negatively related to the lowest O₂ saturation (r?=?0.266; p?<?0.037). The OSA patients associated with hypertension showed elevated TRX level (17.70?±?6.98 vs. 13.43?±?5.83 ng/ml; t?=?2.434, p?<?0.018). The cutoff value of TRX for identifying OSA was 9.39 ng/ml (sensitivity 91 %, specificity 78 %), and its cutoff value for differentiating moderate–severe OSA from mild OSA was 11.79 ng/ml (sensitivity 75 %, specificity 65 %).

Conclusion

These results suggest that plasma TRX level is associated with the severity of OSA. Therefore, TRX may be used as a severity indicator of OSA.