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.     

Postoperative complications in obstructive sleep apnea

Study objectives

This study was conducted to determine whether postoperative complications are increased in patients with obstructive sleep apnea (OSA) and to study the impact of the severity of OSA and preoperative use of continuous positive airway pressure (CPAP) on the postoperative outcome.

Design and setting

This study is retrospective in nature and was undertaken at the VA Medical Center.

Participants and methods

Three hundred seventy patients who had undergone both a major surgical procedure and a sleep study from 2000 to 2010 were identified. Patients were divided into four groups: OSA negative (apnea–hypopnea index (AHI)?<?5/h), OSA positive; mild: AHI 5 to <15/h; moderate: AHI 15 to <30/h; and severe: AHI?≥?30/h. No intervention was made during the course of the study. Postoperative complications namely respiratory, cardiac, neurological, and unplanned intensive care unit transfers were collected.

Results

There were 284 (76.8 %) patients having OSA and 86 (23.2 %) without OSA. The overall incidence of total complications was significantly higher in the OSA patients compared with the control patients (48.9 vs. 31.4 %; odds ratio 2.09, 95 % CI 1.25–3.49). There was no significant difference in total complications between those using and not using CPAP prior to hospitalization. Patients with sleep apnea had a higher incidence of respiratory complications compared to patients without sleep apnea (40.4 vs. 23.2 %; odds ratio 2.24, 95 % CI 1.29–3.90). There was no significant difference in major cardiac complications in the OSA patients compared with the control patients (13.0 vs. 9.3 %; odds ratio 1.46, 95 % CI 0.65–3.26).

Conclusion

OSA is associated with a significantly increased rate of postoperative complications.     

Severe obstructive sleep apnea increases mortality in patients with ischemic heart disease and myocardial injury

Objectives

We hypothesized that obstructive sleep apnea (OSA) has a dose-dependent impact on mortality in those with ischemic heart disease or previous myocardial injury.

Methods

We performed a retrospective cohort study of 281 consecutive OSA patients with a history of myocardial injury as determined by elevated troponin levels or with known existing ischemic heart disease. We compared survival between those with severe OSA [apnea–hypopnea index (AHI) ≥30] and those with mild to moderate OSA (AHI >5 and <30).

Results

Of the 281 patients (mean age 65 years, mean BMI 34, 98% male, 58% with diabetes), 151 patients had mild-moderate OSA and 130 had severe OSA. During a mean follow-up of 4.1 years, there were significantly greater deaths in the severe OSA group compared to the mild-moderate OSA group [53 deaths (41%) vs. 44 deaths (29%), respectively, p?=?0.04]. The adjusted hazard ratio for mortality with severe OSA was 1.72 (95% confidence interval 1.01–2.91, p?=?0.04).

Conclusions

The severity of obstructive sleep apnea is associated with increased risk of death, and risk stratification based on OSA severity is relevant even in the diseased cardiac patient.     

Gender and age influence the effects of slow-wave sleep on respiration in patients with obstructive sleep apnea

Introduction

Obstructive sleep apnea (OSA) is influenced by sleep architecture with rapid eye movement (REM) sleep having the most adverse influence, especially in women. There is little data defining the influence of slow-wave sleep (SWS) on OSA. We wished to study the influence of SWS on OSA and identify differences attributable to gender and/or age, if any.

Methods

Retrospective study of polysomnography (PSG) records of adult patients referred for diagnostic PSG. Records were excluded if they underwent split night or positive airway pressure titration studies, had <180 min of total sleep time (TST) and/or <40% sleep efficiency, or had SWS <5 min and/or <1% of TST. The apnea–hypopnea index (AHI) recorded during SWS was compared with that measured during other non-rapid eye movement (NREM) sleep and during REM sleep. The REM–SWS difference in AHI was measured, and compared between genders.

Results

Records from 239 patients were included. The mean AHI in all subjects was 17.7?±?22.6. The SWS AHI was 6.8?±?18.9, compared to the REM AHI of 24.9?±?25.8, and NREM AHI of 15.8?±?22.8. Females had significantly higher SWS by percentage, and lower NREM AHI (P?<?0.0001) and SWS AHI (P?=?0.03). Among patients with OSA (AHI ≥5), the difference between REM AHI and SWS AHI was greater in women than in men (34.2?±?27.4 vs. 21.6?±?26.0, P?=?0.006).

Conclusions

The upper airway appears to be less susceptible to OSA during SWS than during REM and other NREM sleep. This may be related to phase-specific influences on both dynamic upper airway control as well as loop gain. Gender and age appear to modify this effect.     

Obstructive sleep apnea and acute myocardial infarction severity: ischemic preconditioning?

Background

Obstructive sleep apnea (OSA) is characterized by intermittent hypoxia (IH). In animal models, IH has been shown to protect the myocardium during periods of ischemia by reducing infarct size. However, this phenomenon of “ischemic preconditioning” has not been investigated among OSA patients with acute myocardial infarction (MI). This study investigates the role of OSA on MI severity as measured by cardiac enzymes, specifically troponin-T, among patients with an acute MI.

Methods

This is an observational cohort study of patients ≥18 years of age who were hospitalized with an acute MI. Each participant underwent portable sleep monitoring (Apnea Link Plus); OSA was defined as an apnea–hypopnea index ≥5/h. Multivariable regression analysis was conducted to assess the relationship between OSA and highly sensitive troponin-T levels.

Results

In our entire cohort of acute MI patients (n?=?136), 77 % of the sample had evidence of sleep disordered breathing, with 35 % of the sample having OSA (i.e., an AHI >5). Higher AHI was associated with lower peak troponin-T levels in partially adjusted models (β?=??0.0320, p?=?0.0074, adjusted for age, gender, and race) and fully adjusted models (β?=??0.0322, p?=?0.0085) (additionally adjusted for smoking, hypertension, hyperlipidemia, body mass index, history of prior cardiovascular or cerebrovascular disease, diabetes and baseline admission creatinine levels). The mean value of the log-transformed peak troponin-T variable was used to dichotomize the outcome variable. In both partially (OR 0.949, CI 0.905–0.995, p?=?0.03) and fully adjusted (OR 0.918, CI 0.856–0.984, p?=?0.0151) logistic regression models, the OR for AHI suggests a protective effect on high troponin-T level.

Conclusions

Our study demonstrates that patients with OSA have less severe cardiac injury during an acute non-fatal MI when compared to patients without OSA. This may suggest a cardioprotective role of sleep apnea during acute MI via ischemic preconditioning.     

Effects of tonsillectomy on sleep study parameters in adult patients with obstructive sleep apnea—a prospective study

Objective

The objective of this study is to evaluate the efficacy of tonsillectomy in reduction of respiratory disturbance index (RDI) and other sleep study parameters in patients with obstructive sleep apnea (OSA).

Methods

This study involves 34 adults with OSA and Friedman grade 3 or 4 tonsils. All 34 patients were treated with tonsillectomy, as the only surgical treatment for OSA from 2007 to 2011. Pre- and postoperative polysomnography were performed in all these patients.

Results

Prior to tonsillectomy, 21 patients had severe, 9 had moderate, and 4 had mild OSA. Surgical response rate (defined as 50 % or more reduction in apnea–hypopnea index (AHI) and a postoperative AHI of less than 20) was 71.4 % among patients with severe OSA, 77.7 % among patients with moderate, and 75 % among patients with mild. Among all the 34 patients, there was a reduction of 24.6 (p?=?0.000) in the RDI postoperatively. In our sub-analysis, we arbitrarily divided the patients into three groups: patients with RDI less than 30, patients with RDI between 30 and 60, and patients with RDI above 60. It showed that, in the group with RDI >60, an average reduction of RDI by 57.6 (p?=?0.000) was achieved and was the greatest reduction in RDI.

Conclusions

Tonsillectomy alone may be considered as an effective first line surgical procedure in the treatment of OSA in selected patients. Patients with Friedman grade 3 or 4 tonsils may be considered for tonsillectomy as the initial surgical procedure, reserving other upper airway procedures at a later stage if necessary.     

Influence of sleep apnea severity on blood pressure variability of patients with hypertension

Purpose

Obstructive sleep apnea (OSA) is a risk factor for the development of hypertension and cardiovascular disease. Apnea overloads the autonomic cardiovascular control system and may influence blood pressure variability, a risk for vascular damage independent of blood pressure levels. This study investigates the hypothesis that blood pressure variability is associated with OSA.

Methods

In a cross-sectional study, 107 patients with hypertension underwent 24-h ambulatory blood pressure monitoring and level III polysomnography to detect sleep apnea. Pressure variability was assessed by the first derivative of blood pressure over time, the time rate index, and by the standard deviation of blood pressure measurements. The association between the apnea–hypopnea index and blood pressure variability was tested by univariate and multivariate methods.

Results

The 57 patients with apnea were older, had higher blood pressure, and had longer duration of hypertension than the 50 patients without apnea. Patients with apnea–hypopnea index (AHI) ≥ 10 had higher blood pressure variability assessed by the standard deviation than patients with AHI < 10 during sleep (10.4?±?0.7 versus 8.0?±?0.7, P?=?0.02) after adjustment for age, body mass, and blood pressure. Blood pressure variability assessed by the time rate index presented a trend for association during sleep (P?=?0.07). Daytime blood pressure variability was not associated with the severity of sleep apnea.

Conclusion

Sleep apnea increases nighttime blood pressure variability in patients with hypertension and may be another pathway linking sleep abnormalities to cardiovascular disease.     

High prevalence of obstructive sleep apnea in patients with resistant paroxysmal atrial fibrillation after pulmonary vein isolation

Objectives

To address the question whether obstructive sleep apnea (OSA) is associated with the recurrence of paroxysmal atrial fibrillation (AF) in patients treated with ≥2 pulmonary vein isolation procedures.

Patients and Methods

In this study, we included adults with therapy-resistant symptomatic paroxysmal AF, defined as AF recurring after ≥2 PV-isolation procedures (n?=?23). For comparison, we selected another cohort of patients being successfully treated by one PV isolation without AF recurrence within 6 months (n?=?23). PV isolation was performed by radiofrequency with an open irrigated tip catheter. Each of the 46 participants completed an overnight polygraphic study. The two groups were matched for age, gender, and ejection fraction. Patients were late middle-aged (65?±?7 vs 63?±?10 years, P?=?0.23), white (100%), and overweight (BMI 27.3?±?3.6 vs. 27.2?±?4.6 kg/m², P?=?0.97).

Results

The prevalence of sleep apnea, defined as an apnea–hypopnea index (AHI) of >5 per hour of sleep, was 87% in patients with therapy-resistant AF compared to 48% in the control cohort (P?=?0.005). In addition, OSA was more severe in the resistant AF group indicated by a significantly higher AHI (27?±?22 vs 12?±?16, P?=?0.01).

Conclusion

The extraordinarily high prevalence of sleep apnea in patients with recurrent paroxysmal AF supports its presumable role in the pathogenesis of AF and demands further controlled prospective trials. Moreover, OSA should inherently be considered in patients with therapy-resistant AF.     

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.     

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.     

Pro-atherogenic cytokine profile of patients with suspected obstructive sleep apnea

Purpose

Systemic inflammation is important in the pathogenesis of cardiovascular disease (CVD). We sought to characterize the systemic inflammatory profile associated with obstructive sleep apnea (OSA).

Methods

Adult patients referred for suspected OSA at the University of British Columbia Hospital Sleep Disorders Program were recruited for our study. Patients using HMG CoA inhibitors or a history of CVD were excluded. Fasting serum samples were obtained the morning after their diagnostic polysomnograms. Samples were tested for the following circulating inflammatory mediators: interferon gamma; interleukins 1B, 6, and 8; intercellular and vascular cell adhesion molecules (sICAM-1 and sVCAM-1); and leptin using a multiplex Luminex System.

Results

There were 176 patients; 68% were male, mean age?=?50?±?(SD) 11 years, mean apnea/hyponea index (AHI)?=?22.9?±?22/h, mean desaturation (i.e. % of sleep time spent below an oxyhemoglobin saturation of 90%)?=?5.4%?±?15, and mean body mass index (BMI)?=?32.2?±?8 kg/m². In univariate analyses, only leptin, sVCAM-1, and sICAM-1 were significantly associated with indices of OSA severity (i.e. AHI and/or desaturation). In multivariate linear regression analyses that controlled for BMI, gender, age, and current smoking; desaturation persisted as a significant independent predictor for elevated sVCAM-1 and leptin.

Conclusions

We did not find significant associations between OSA and markers of activated innate immunity (IL-1B, 6, and 8). However, OSA severity was independently associated with serum levels of sVCAM-1 and leptin; these may represent mechanisms involved in the pathogenesis of OSA-related CVD.     

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.     

Nocturnal hypoxemia biomarker predicts sleepiness in patients with severe obstructive sleep apnea

Purpose

This study aims to assess the association between excessive daytime sleepiness (EDS) and variables extracted from the pulse-oximetry signal obtained during overnight polysomnography.

Methods

A cross-sectional design was used to study the relation between four hypoxemia variables and EDS as determined by Epworth Sleepiness Scale scores (ESSS) in 200 consecutive patients, newly diagnosed with obstructive sleep apnea (OSA), as defined by an apnea–hypopnea index (AHI)?≥?15. Hypoxemia measurements were compared between sleepy (ESSS?≥?10) and nonsleepy (ESSS?<?10) patients before and after dichotomizing the cohort for each hypoxemia variable (and for AHI) such that there were 35 (165) patients in each of the corresponding higher (lower) subcohorts. The hypoxemia variables were combined into a biomarker, and its accuracy for predicting sleepiness in individual patients was evaluated. We planned to interpret prediction accuracy above 80 % as evidence that hypoxemia predicted EDS.

Results

Hypoxemia was unassociated with sleepiness in OSA patients with AHI in the range of 15 to 50. In patients with AHI?>?50, the hypoxemia biomarker (but not individual hypoxemia variables) predicted sleepiness with 82 % accuracy.

Conclusion

Nocturnal hypoxemia as determined by a polyvariable biomarker reliably predicted EDS in patients with severe OSA (AHI?>?50), indicating that oxygen fluctuation had a direct role in the development of EDS in patients with severe OSA.     

Validation of ApneaLink Ox™ for the diagnosis of obstructive sleep apnea

Objective

The aim of the study was to validate the automatic and manual analysis of ApneaLink Ox? (ALOX) in patients with suspected obstructive sleep apnea (OSA).

Methods

All patients with suspected OSA had a polysomnography (PSG) and an ALOX performed in the sleep laboratory. For automatic analysis, hypopnea was defined as a decrease in airflow ≥30 % of baseline for at least 10 s plus oxygen desaturation ≥3 or 4 %. While for the manual analysis, hypopnoea was considered when a reduction of airflow ≥30 % of ≥10 s plus oxygen desaturation ≥3 % or increase in cardiac rate ≥5 beats/min were identified or, when only a reduction of airflow ≥50 % was observed. OSA was defined as a respiratory disturbance index (RDI) ≥5. The apnea/hypopnea automatic index (AHI3-a, AHI4-a) and manual index were estimated. Receiver operating characteristics (ROC) analysis and the agreement between ALOX and PSG were performed.

Results

Fifty-five patients were included (38 men; mean age, 48.2; median, RDI 15.1; median BMI, 30 Kg/m²). The automatic analysis of ALOX under-estimated the RDI from PSG, mainly for the criterion of oxygen desaturation ≥4 % (AHI3-a–RDI, ?3.6?±?10.1; AHI4-a–RDI, ?6.5?±?10.9, p?<?0.05). The autoscoring from ALOX device showed a better performance when it was set up to identify hypopneas with an oxygen desaturation criterion of ≥3 % than when it was configured with an oxygen desaturation criterion of ≥4 % (area under the receiver operator curves, 0.87 vs. 0.84). Also, the manual analysis was found to be better than the autoscoring set up with an oxygen desaturation of ≥3 % (0.923 vs. 0.87). The manual analysis showed a good interobserver agreement for the classification of patients with or without OSA (k?=?0.81).

Conclusion

The AHI obtained automatically from the ApneaLink Ox? using oxygen desaturation ≥3 % as a criterion of hypopnea had a good performance to diagnose OSA. The manual scoring from ApneaLink Ox? was better than the automatic scoring to discriminate patients with OSA.     

Home sleep study characteristics in patients with mucopolysaccharidosis

Background

Mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage disorders caused by the deficiency of hydrolases involved in the degradative pathway of glycosaminoglycans. In MPS, upper airway obstruction may result from multiple causative factors which may impact severely upon morbidity and mortality.

Methods

We evaluated upper airway obstructive disease and related clinical findings through home sleep study in 19 patients (11 with MPS VI, 4 with MPS I, 4 with MPS II) with MPS followed at Gazi University Pediatric Metabolic Unit. Patients underwent home-based sleep measurements, and sleep respiratory problems were asked in a detailed clinical history. Measurements of apnea, apnea–hypopnea index (AHI), hypopnea index, oxygen desaturation index, and minimal oxygen saturation were obtained through home sleep study.

Results

For 19 children, the disorder was normal in 1, mild (AHI?=?1.5–5/h) in 5, moderate (AHI?=?5–10/h) in 2, and severe (AHI?>?10/h) in 11. The prevalence of OSA was 94.7 % (18/19) in patients with MPS. Snoring, witnessed apnea, pectus carinatum, and macroglossia were the main clinical findings. Echocardiograms showed evidence of pulmonary hypertension in 13 patients.

Conclusion

Home sleep study is a quick and accessible screening test to determine the abnormalities of breathing during sleep and enables clinicians to take necessary action for patients with severe manifestations.     

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.     

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.     

Comparison of a simple obstructive sleep apnea screening device with standard in-laboratory polysomnography

Background

Obstructive sleep apnea (OSA) is a common underdiagnosed sleep disorder. Various strategies have been employed to easily screen for OSA. The ApneaStrip® (AS - S.L.P. Ltd, Tel Aviv, Israel) is an FDA approved OSA screening device applied to the upper lip at home. We evaluated the performance of this device against simultaneous in-laboratory polysomnography (PSG) in a group of well-characterized OSA patients.

Methods

Diagnostic PSG was performed in 56 patients (29 M, 37 F; age 48.9?±?14.6 years; body mass index [BMI] 37.5?±?9.0 kg/m²; apnea-hypopnea index—events/h—[AHI] 32.8?±?22.9). The AS was applied and positioned to detect nasal and oral airflow. The AS gives a “positive” result for AHI?≥?15. We examined the sensitivity and specificity of the AS against three thresholds derived from PSG: AHI?≥?5, AHI?≥?15 (company recommendation), and AHI?≥?30.

Results

For PSG AHI?≥?15, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the AS were 80, 54.5, 87.8, and 40 %, respectively. For PSG AHI?≥?5, the values were 75.1, 66.7, 97.1, and 13.3 %, respectively. For PSG AHI?≥?30, the values were 86.9, 36.2, 48.8, and 80 %, respectively. There were no significant modifying effects of age, BMI, gender, hypertension, diabetes, lung disease, and heart disease.

Conclusion

The AS has a high sensitivity for detection of OSA with AHI?≥?15, but only modest specificity. The AS could be a useful component of an OSA screening program; however, negative results should be interpreted cautiously.

     

The effect of nightly nasal CPAP treatment on nocturnal hypoxemia and sleep disorders in mustard gas-injured patients

Introduction

Sleep-related breathing disorders are associated with unusual respiratory pattern or an abnormal reduction in gas exchange during sleep that is common in sulfur mustard (SM) exposure.

Methods

We compared 57 Iranian male patients injured with SM and had any complaints of sleep problems with an age-matched group of 21 Iranian male patients who had complaints of sleep problems and were not chemically injured; this group had Epworth Sleepiness Scale (ESS) above 10 and whom referred for polysomnography. Split-night studies were performed for patients with diagnostic polysomnography for obstructive sleep apnea (OSA) and respiratory events. We then studied respiratory events including episodes of OSA, apnea–hypopnea index (AHI) and respiratory disturbance index (RDI).

Results

The mean age in mustard-exposed patients was 48.14?±?8.04 years and in age-matched group, 48.19?±?8.39 years. In mustard exposed patients, there were statistical differences for the episodes of OSA (p?=?0.001), AHI (p?=?0.001), and RDI (p?=?0.001) between two segments of split-night studies. In the age-matched group, there were statistically differences for each parameter (episodes of OSA (p?=?0.001), AHI (p?=?0.001), and RDI (p?=?0.001)). There were no significant differences between two groups.

Conclusion

This study indicated that the incidence of respiratory events and nocturnal hypoxemia during sleep in mustard-exposed patients were high and treatment with CPAP significantly reduced all these events.     

Surface cephalometric and anthropometric variables in OSA patients: statistical models for the OSA phenotype

Study objective

We used statistical modelling to probe the contributions of anthropometric and surface cephalometric variables to the OSA phenotype.

Design

The design is prospective cohort study.

Setting

The setting is community-based and sleep disorder laboratory.

Patients or participants

Study #1—Model development study: 147 healthy asymptomatic volunteers (62.6 % Caucasian; age, 18–76 years; 81 females; median multivariable apnea prediction index?=?0.15) and 140 diagnosed OSA patients (84.3 % Caucasian; age, 18–83 years; 41 females; polysomnography [PSG] determined apnea–hypopnea index >10 events/h). Study #2—Model test study: 345 clinic patients (age, 18–86 years; 129 females) undergoing PSG for diagnosis of OSA.

Intervention

We measured 10 anthropometric and 34 surface cephalometric dimensions (calipers) and calculated mandibular enclosure volumes for study #1 and recorded age and neck circumference for study #2. Statistical modelling included principal component (PC), logistic regression, and receiver–operator curve analyses.

Measurements and results

Model development study: A regression model incorporating three identified PC predicted OSA with 88 % sensitivity and specificity. However, a simplified model based on age and NC alone was equally effective (87 % sensitivity and specificity). Model test study: The simplified model predicted OSA with high sensitivity (93 %) but poor specificity (21 %).

Conclusion

We conclude that in our clinic-based cohort, craniofacial bony and soft tissue structures (excluding neck anatomy) do not play a substantial role in distinguishing patients with OSA from those without. This may be because craniofacial anatomy does not contribute greatly to the pathogenesis of OSA in this group or because referral bias has created a relatively homogeneous phenotypic population.