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PubMed1995

Breath-holding time in normal subjects, snorers, and sleep apnea patients.

BACKGROUND: The onset of irregular inspiratory muscle activity has been observed toward the breakpoint of the breath-holding maneuver. We wondered if this was similar to the increased respiratory effort with paradoxical breathing seen during the resolution of an apnea in obstructive sleep apnea syndrome (OSAS). STUDY OBJECTIVE: To compare the breakpoint of breath holding in normal subjects, OSAS patients, and snorers. METHODS: Thirty normal subjects, 30 patients with OSAS, and 16 snorers performed serial breath-holding maneuvers at functional residual capacity (FRC) under standardized pretest conditions using the rebreathing method of Read. RESULTS: Intergroup comparisons were carried out by analysis of variance with post hoc Tukey's Highest Significant Difference tests. Basal end-tidal carbon dioxide (EtCO2) was significantly higher in OSAS than in normal subjects and snorers. Basal breath-holding time (BHT) was shorter in OSAS as compared with that in normal subjects and snorers (p < 0.05). The maximal EtCO2 level attained was higher in OSAS as compared with normal subjects (p < 0.05) and snorers (p = 0.052). The maximal BHT in OSAS was shorter than in normal subjects (p < 0.05) but not in snorers. The slope of BHT/EtCO2 differed significantly in OSAS compared with normal subjects and snorers (p < 0.05). No significant correlation was found between slope BHT/EtCO2 and age or body mass index using multiple regression analysis. The FRC of OSAS patients and snorers were similar (p = 0.792). CONCLUSION: We conclude that BHT and slope of BHT/EtCO2 are different in OSAS subjects as opposed to those in normal subjects and snorers.

Carbon Dioxide↗

PubMed1997

Positional vs nonpositional obstructive sleep apnea patients: anthropomorphic, nocturnal polysomnographic, and multiple sleep latency test data.

STUDY OBJECTIVES: To compare anthropomorphic, nocturnal polysomnographic (PSG), and multiple sleep latency test (MSLT) data between positional (PP) and nonpositional (NPP) obstructive sleep apnea (OSA) patients. DESIGN: This is a retrospective analysis of anthropomorphic, PSG, and MSLT data of a large group of OSA patients who underwent a complete PSG evaluation in our sleep disorders unit. The patients were divided in two groups: the PP group, those patients who had a supine respiratory disturbance index (RDI) that was at least two times higher than the lateral RDI, and the NPP group, those patients in whom the RDI in the supine position was less than twice that in the lateral position. SUBJECTS: From a group of 666 consecutive OSA patients whose conditions were diagnosed in our unit from September 1990 to February 1995, 574 patients met the following criteria and were included in the study: RDI > 10; age > 20 years, and body mass index (BMI) > 20. RESULTS: Of all 574 patients, 55.9% were found to be positional. No differences in height were observed but weight and BMI were significantly higher in the NPP group, these patients being on the average 6.5 kg heavier than those in the PP group. The PP group was, on average, 2 years younger than the NPP group. Nocturnal sleep quality was better preserved in the PP group. In this group, sleep efficiency and the percentages of deep sleep (stages 3 and 4) were significantly higher while the percentages of light sleep (stages 1 and 2) were significantly lower than in the NPP group. No differences for rapid eye movement (REM) sleep were found. In addition, wakefulness after sleep onset and the number of short arousals (< 15 s) were significantly lower in the PP group. Apnea index and total RDI were significantly higher and the minimal arterial oxygen saturation in REM and non-REM sleep was significantly lower in the NPP. No differences in periodic limb movements data were found between the two groups. The average MSLT was significantly shorter in the NPP group. Univariate and multivariate stepwise logistic regression analysis showed that the most dominant variable that correlates with positional dependency in OSA patients is RDI, followed by BMI which also adds a significant contribution to the prediction of positional dependency. Age, although significant, adds only a minor improvement to the prediction of this positional dependency phenomenon. A severe, obese, and older OSA patient is significantly less likely to be positional than a mild-moderate, thin, and young OSA patient. In four obese OSA patients who lost weight, a much more pronounced reduction was seen in the lateral RDI than in the supine RDI, and three of these cases who were previously NPP became PP. CONCLUSIONS: In a large population of OSA patients, most were found to have at least twice as many apneas/hypopneas in the supine than in the lateral position. These so-called "positional patients" are on the average thinner and younger than "nonpositional patients." They had fewer and less severe breathing abnormalities than the NPP group. Consequently their nocturnal sleep quality was better preserved and, according to MSLT data, they were less sleepy during daytime hours. RDI was the most dominant factor that could predict the positional dependency followed by BMI and age. RDI showed a threshold effect, the prevalence of PP in those with severe RDI (RDI > or = 40) was significantly lower than in those OSA patients with mild-moderate RDI. BMI showed a major significant inverse relationship with positional dependency, while age had only a minor although significant inverse relationship with it. Body position during sleep has a profound effect on the frequency and severity of breathing abnormalities in OSA patients.

Adult↗

PubMed1998

CT in the evaluation of the upper airway in healthy subjects and in patients with obstructive sleep apnea syndrome.

AIM: To study if the caliber of the upper airway, measured by CT, allows us to distinguish patients with obstructive sleep apnea syndrome (OSAS) from healthy people. PATIENTS AND METHODS: Sixteen OSAS patients (with an apnea-hypopnea index > 10) and 39 healthy volunteers were studied. Polysomnography and CT of the upper airways during awake periods were performed in both groups. We used third-generation equipment (Toshiba model TCT 600QT). The area of the nasopharynx, oropharynx, and hypopharynx (in inspiration and expiration), the uvula diameter, and retropharyngeal tissue were evaluated. The simultaneous identification of the variables that differentiate between control and OSAS groups was determined by a multivariate discriminant model. RESULTS: The retropharyngeal tissue in OSAS men was greater than those of the control men (10.3+/-3.6 mm vs 6.4+/-2.7 mm; p < 0.01). The multivariate analysis was performed on the 29 men (14 OSAS and 15 non-OSAS) who had information compiled in the selected parameters. The retropharyngeal tissue, expiratory hypopharynx, and uvular diameter are used to create a discriminant model (Wilks' lambda=0.556; p < 0.01). Two non-OSAS and five OSAS patients were incorrectly classified by this model as members of the other group (total rate of error, 24.14%). Therefore, the point estimates of specificity and sensitivity are 86.67% and 64.29%, respectively, for this model. The Pearson correlation coefficient between body mass index and retropharyngeal tissue is 0.63 (p < 0.001). CONCLUSIONS: CT could play an important role in studying the upper airway in patients with OSAS. The determination of the retropharyngeal tissue by CT could be a useful procedure to evaluate OSAS.

Adult↗

PubMed1999

Neural network prediction of obstructive sleep apnea from clinical criteria.

STUDY OBJECTIVES: Clinical prediction models for the diagnosis of obstructive sleep apnea (OSA) have lacked the accuracy necessary to confidently replace polysomnography (PSG). Artificial neural networks are computer programs that can be trained to predict outcomes based on experience. This study was conducted to test the hypothesis that a generalized regression neural network (GRNN) could accurately classify patients with OSA from clinical data. STUDY DESIGN: Retrospective review. SETTING: Regional sleep referral center. PATIENTS: Randomly selected records of patients referred for possible OSA. MEASUREMENTS: The neural network was trained using 23 clinical variables from 255 patients, and the predictive performance was evaluated using 150 other patients. RESULTS: The prevalence of OSA in this series of 405 patients (293 men and 112 women) was 69%. The trained GRNN had an accuracy of 91.3% (95% confidence interval [CI], 86.8 to 95.8). The sensitivity was 98.9% for having OSA (95% CI, 96.7 to 100), and the specificity was 80% (95% CI, 70 to 90). The positive predictive value that the patient would have OSA was 88.1% (95% CI, 81.8 to 94.4), whereas the negative predictive value that the patient would not have OSA (if so classified) was 98% (95% CI, 94 to 100). CONCLUSIONS: Appropriately trained GRNN has the ability to accurately rule in OSA from clinical data, and GRNN did not misclassify patients with moderate to severe OSA. In this study, use of the neural network could have reduced the number of PSG studies performed. Prospective validation of the neural network for the diagnosis of OSA is now required.

Adolescent↗

PubMed1999

Value of clinical, functional, and oximetric data for the prediction of obstructive sleep apnea in obese patients.

OBJECTIVE: To evaluate the diagnostic value of clinical features, pulmonary function testing, blood gas tensions, and oximetric data for case finding of obstructive sleep apnea (OSA) before polysomnography (PSG) in a series of consecutive overweight patients. METHODS: We studied a population of 102 consecutive patients referred by an obesity clinic for suspected OSA, in whom body mass index was > or = 25 kg/m(2). The following tests were performed: clinical score (CS), pulmonary function tests (PFTs), measurement of arterial blood gas tensions, nocturnal oximetry, and full-night PSG. RESULTS: Six of 34 women and 34 of 68 men had OSA, defined by an apnea-hypopnea index > or = 15. CS and the cumulative time spent below 80% arterial oxygen saturation (SaO(2)) were higher, and PaO(2), minimal SaO(2), and mean nocturnal SaO(2) (mSaO(2)) were lower in OSA patients than in non-OSA patients. Logistic regression showed that sex, CS, and the ratio of FEV(1) over forced expiratory volume in 0.5 s (an index of upper airway obstruction on flow-volume curves) and mSaO(2), expressed as categorical variables, were independent predictors of OSA. None of these individual variables had a satisfactory diagnostic value for the diagnosis of OSA. A logistic regression model including sex and all continuous variables would have allowed us to predict the presence or absence of OSA confidently in 72.5% of the population, in whom the positive predictive value of the model was 94% and the negative predictive value was 90%. CONCLUSION: In obese patients referred to a respiratory sleep laboratory and evaluated by CS, PFTs, arterial blood gases, and oximetry, no individual sign or symptom may accurately predict the presence or absence of OSA. Provided that it is validated in prospective studies, a logistic regression model using these variables may be useful for the prediction of OSA.

Adult↗

PubMed2000

Serum leptin and vascular risk factors in obstructive sleep apnea.

STUDY OBJECTIVES: To define the metabolic profile relevant to vascular risks in obstructive sleep apnea (OSA) and the role of leptin resistance in this risk profile. DESIGN: Case control study. SETTING: Sleep Laboratory, Queen Mary Hospital, University of Hong Kong, China. METHODS: Thirty OSA subjects were matched with 30 non-OSA subjects for body mass index (BMI), age, sex, and menopausal status. Neck, waist, and hip girth, skinfold thickness, and fasting serum levels of lipids, glucose, insulin, and leptin were compared between these two groups. RESULTS: Compared with control subjects with a similar BMI but without OSA, the OSA group had a significantly more adverse vascular risk factor profile, including dyslipidemia, higher diastolic BP, insulin resistance, and greater adiposity reflected by skinfold thickness. OSA subjects also had higher circulating leptin levels (9.18+/-4.24 ng/mL vs 6.54+/-3.81 ng/mL, mean +/- SD, p = 0.001). Serum leptin levels correlated positively with BMI, skinfold thickness, serum cholesterol, low-density lipoprotein cholesterol, insulin, insulin/glucose ratio, apnea-hypopnea index, and oxygen desaturation time; multiple stepwise regression analysis identified skinfold thickness, waist/hip ratio, serum low-density lipoprotein cholesterol, and diastolic BP as independent correlates, while only serum insulin and diastolic BP were independent correlates in OSA subjects. After treatment with nasal continuous positive airway pressure for 6 months, there was a significant decrease in circulating leptin (p = 0.01) and triglyceride levels (p = 0.02) without change in other parameters. CONCLUSION: Despite controlling for BMI, OSA subjects showed distinct profiles with clustering of vascular risk factors. Hyperleptinemia was present in the OSA subjects, but it can be normalized by treatment with nasal continuous positive airway pressure, suggesting that increased leptin resistance was not the cause of OSA or its associated vascular risks.

Adult↗

PubMed2000

Inspiratory effort sensation to added resistive loading in patients with obstructive sleep apnea.

STUDY OBJECTIVES: Repeated episodes of upper-airway occlusion are the main characteristics of patients with obstructive sleep apnea (OSA) during sleep. It has been reported that an impairment in the sensation of detection and a depression of ventilatory compensation to added load could be observed in such patients. In this study, we examined patients with OSA to evaluate the inspiratory effort sensation (IES), ventilation, and mouth occlusion pressures during added resistive loading while awake and to determine whether they can be reversed by nasal continuous positive airway pressure (CPAP) treatment. DESIGN: A hospital-based case-control study. SETTING: A sleep laboratory of a medical unit in Japan. SUBJECTS: Seventeen patients with moderate to severe OSA and 10 control subjects were included in this study. MEASUREMENTS: All patients with OSA had undergone standard nocturnal polysomnography. Patients with OSA and control subjects were evaluated for IES measured by a modified Borg score, ventilation, and mouth occlusion pressure during control and inspiratory resistive loaded breathing. These tests were repeated in all patients with OSA after 2 weeks of nasal CPAP treatment. RESULTS: IES to inspiratory resistive loading was lower in patients with OSA than in control subjects. There were no differences in ventilation and mouth occlusion pressure between patients and control subjects during loaded breathing. After 2 weeks of nasal CPAP, the decreased IES was increased in patients with OSA. CONCLUSION: In patients with OSA, the decreased IES to inspiratory resistive loaded breathing is reversible with nasal CPAP. This could be one additional benefit of nasal CPAP in the treatment of OSA.

Airway Obstruction↗

PubMed2001

The obesity-hypoventilation syndrome revisited: a prospective study of 34 consecutive cases.

STUDY OBJECTIVES: Obesity has many detrimental effects on the respiratory function and may lead to chronic hypoventilation in some patients, an association known as the obesity-hypoventilation syndrome (OHS). In many cases, patients with OHS also have sleep apneas. Hereafter, we describe several features of a cohort (n = 34) of patients with OHS and show the comparisons with a large cohort (n = 220) of patients with obstructive sleep apnea syndrome (OSAS). We compare also OHS patients with a group of patients with the association of OSAS and COPD, also known as "overlap" patients. DESIGN: Descriptive analysis of prospectively collected clinical data. SETTING: Respiratory care unit and sleep laboratory of university hospital. RESULTS: In OHS patients, OSAS was present in most of the cases (23 of 26 patients). However, in three patients, OHS was not associated with OSAS, showing that obesity per se may lead to chronic hypoventilation. As expected by definition, OHS patients had, on average the worst diurnal arterial blood gas measurements, compared to the other groups. For the OHS patients, the mean diurnal PaO(2) was 59 +/- 7 mm Hg, which was significantly different from the PaO(2) of the OSAS patients (75 +/- 10 mm Hg; p = 0,001) but also from the overlap patients (66 +/- 10 mm Hg; p = 0.015). Pulmonary hypertension (ie, mean pulmonary artery pressure > 20 mm Hg) was more frequent in OHS patients than in "pure" OSAS patients (58% vs 9%; p = 0.001). CONCLUSION: Patients with OSAS and chronic respiratory insufficiency had in most cases an associated OHS or COPD. Patients with OHS were older than patients with pure OSAS. They had mild-to-moderate degrees of restrictive ventilatory pattern due to obesity. Severe gas exchange impairment and pulmonary hypertension were quite frequent. The association of OHS and OSAS was the rule. However, in three patients, OHS was not associated with OSAS, suggesting that OHS is an autonomous disease.

Chronic Disease↗

PubMed2002

Increased 8-isoprostane and interleukin-6 in breath condensate of obstructive sleep apnea patients.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is characterized by repeated episodes of upper airways obstruction during sleep that result in episodes of hypoxia. An increase of systemic biomarkers of inflammation and oxidative stress has been found in patients with OSA and obesity. DESIGN: The aim of this study was to measure the levels of markers of inflammation (interleukin [IL]-6) and oxidative stress (8-isoprostane) in the exhaled breath condensate of OSA and obese patients. PATIENTS AND METHODS: Eighteen OSA patients (13 men; mean [+/- SEM] age, 44 +/- 7 years), 10 obese subjects (4 men; mean age, 39 +/- 8 years), and 15 healthy age-matched subjects (8 men; mean age, 42 +/- 4 years) were recruited. IL-6 and 8-isoprostane were measured in exhaled breath condensate by a specific enzyme immunoassay kit. MEASUREMENTS AND RESULTS: Higher concentrations of IL-6 were found in OSA patients (8.7 +/- 0.3 pg/mL) than in healthy control subjects (1.6 +/- 0.1 pg/mL; p < 0.0001). Obese subjects also had higher levels than healthy control subjects, but lower levels than OSA patients (2.1 +/- 0.2 pg/mL, p < 0.05 and p < 0.0001 respectively). Furthermore, 8-isoprostane levels were found to be higher in OSA patients (7.4 +/- 0.7 pg/mL) than in obese subjects (5 +/- 0.3 pg/mL; p = 0.4) and healthy subjects (4.5 +/- 0.5 pg/mL; p < 0.005). We found a positive correlation between these two markers and neck circumference and apnea/hypopnea index. CONCLUSIONS: These findings suggest that inflammation and oxidative stress are characteristic in the airways of OSA patients but not in obese subjects, and that their levels depend on the severity of the OSA. The measurement of IL-6 and 8-isoprostane levels may prove to be useful in screening and monitoring obese patients who have a high risk of developing OSA.

Adult↗

PubMed2003

Relationship of systolic BP to obstructive sleep apnea in patients with heart failure.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is an independent risk factor for hypertension in the general population. Hypertension is, in turn, an important risk factor for the development and progression of congestive heart failure (CHF). Our objective was to determine whether OSA would be associated with elevated daytime BP in medically treated patients with CHF. DESIGN: Cross-sectional study. SETTING: Tertiary care, university-affiliated sleep disorders and heart failure clinics. PATIENTS: Three hundred one consecutive patients with CHF. MEASUREMENTS AND RESULTS: We measured daytime BP and performed overnight sleep studies to assess for the presence of OSA. Among these patients, OSA was present in 121 patients (40%) and their systolic BP was significantly higher than in patients without OSA. Patients with OSA were 2.89 times (95% confidence interval, 1.25 to 6.73) more likely to have systolic hypertension (ie, BP > or = 140 mm Hg) than those without OSA after controlling for other risk factors, including obesity. The degree of systolic BP elevation was directly related to the frequency of obstructive apneas and hypopneas. CONCLUSIONS: In medically treated patients with CHF, daytime systolic BP and the prevalence of systolic hypertension are significantly increased in patients with OSA, compared to those without OSA, independent of other potentially confounding factors. OSA may therefore have contributed to the presence of systolic hypertension in some of these patients.

Aged↗

PubMed2004

Elevated production of tumor necrosis factor-alpha by monocytes in patients with obstructive sleep apnea syndrome.

STUDY OBJECTIVES: Tumor necrosis factor (TNF)-alpha is involved in the pathogenesis of atherosclerosis. In the present study, we examined TNF-alpha production by monocytes, serum levels of TNF-alpha, and the effects of nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnea syndrome (OSAS). DESIGN: Prospective observational study. SETTING: University hospital. SUBJECTS: Twenty-four patients with OSAS, 15 obese control subjects, and 12 healthy subjects. MEASUREMENTS AND RESULTS: After polysomnography, venous blood was collected at 5 am. Spontaneous production of TNF-alpha by monocytes for 24 h and serum levels of TNF-alpha were investigated. In addition, patients with moderate-to-severe OSAS were treated with nCPAP for 1 month, and spontaneous production of TNF-alpha by monocytes and serum levels of TNF-alpha were also measured. Spontaneous production of TNF-alpha by monocytes was significantly higher in patients with moderate-to-severe OSAS than in patients with mild OSAS (p < 0.0001), obese control subjects (p < 0.0001), or healthy subjects (p < 0.0001). Serum levels of TNF-alpha were also significantly higher in patients with moderate-to-severe OSAS than in patients with mild OSAS (p < 0.03), obese control subjects (p < 0.0005), or healthy subjects (p < 0.0001). Duration of hypoxia during total sleep time was independently associated with spontaneous production of TNF-alpha by monocytes in patients with OSAS and healthy and obese control subjects. nCPAP significantly decreased spontaneous production of TNF-alpha by monocytes (p < 0.03) and serum levels of TNF-alpha (p < 0.05) in patients with moderate-to-severe OSAS. CONCLUSIONS: Spontaneous production of TNF-alpha by monocytes and serum levels of TNF-alpha are elevated in patients with moderate-to-severe OSAS but are decreased by nCPAP.

Humans↗

PubMed1988

Women and the obstructive sleep apnea syndrome.

Twenty-seven women referred to a sleep disorders clinic for symptoms of obstructive sleep apnea syndrome (OSAS) during one year were systematically analyzed after polygraphic monitoring of sleep and cephalometric x-ray examination. Our subjects, one-third of whom were premenopausal, comprised approximately 12 percent of the total OSAS population seen. Women with OSAS were compared with 110 OSAS men and with a group of 16 women without OSAS but referred to orthodontists for mild dental malocclusion. Women with OSAS were massively obese, much more so than their male counterparts. There was no significant difference between pre- and postmenopausal women, with the exception of the respiratory disturbance index (RDI), which was lower in the postmenopausal group despite similar morbid obesity (seemingly better tolerated by women with OSAS than by men with the same syndrome) and long mandibular plane-hyoid bone distance. The significantly higher RDI noted in premenopausal women, despite equally massive obesity and upper airway abnormalities, is thought to be related to hormonal status and better arousal response. Chronic obstructive lung disease (COLD) seen in a subgroup of women with OSAS did not differentiate this subgroup from the other OSAS patients when oxygen saturation during sleep, frequency of abnormal respiratory events and sleep variables were considered. Massive obesity is the dominant factor for the appearance of OSAS in women.

Adolescent↗

PubMed2003

Severe upper airway obstruction during sleep.

Few disorders may manifest with predominantly sleep-related obstructive breathing. Obstructive sleep apnea (OSA) is a common disorder, varies in severity and is associated with significant cardiovascular and neurocognitive morbidity. It is estimated that between 8 and 18 million people in the United States have at least mild OSA. Although the exact mechanism of OSA is not well-delineated, multiple factors contribute to the development of upper airway obstruction and include anatomic, mechanical, neurologic, and inflammatory changes in the pharynx. OSA may occur concomitantly with asthma. Approximately 74% of asthmatics experience nocturnal symptoms of airflow obstruction secondary to reactive airways disease. Similar cytokine, chemokine, and histologic changes are seen in both disorders. Sleep deprivation, chronic upper airway edema, and inflammation associated with OSA may further exacerbate nocturnal asthma symptoms. Allergic rhinitis may contribute to both OSA and asthma. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA. Treatment with CPAP therapy has also been shown to improve both daytime and nighttime peak expiratory flow rates in patients with concomitant OSA and asthma. It is important for allergists to be aware of how OSA may complicate diagnosis and treatment of asthma and allergic rhinitis. A thorough sleep history and high clinical suspicion for OSA is indicated, particularly in asthma patients who are refractory to standard medication treatments.

Airway Obstruction↗

PubMed2005

Elevated C-reactive protein levels and increased cardiovascular risk in patients with obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular morbidity and mortality. Inflammatory processes associated with OSAS may contribute to cardiovascular morbidity in these patients. C-reactive protein (CRP) is an important serum marker of inflammation. We tested the hypothesis that patients with OSAS have increased plasma CRP. After 173 male subjects underwent polysomnography, 94 were considered to have OSAS (apnea-hypopnea index (AHI) > 5), 38 cardiovascular disease (CVD), and 56 without CVD. Seventy-nine subjects were considered not to have OSAS (AHI < 5) and from among these 57 patients without CVD were enrolled as control subjects. Serum CRP levels were significantly elevated in the OSAS + CVD group compared to the two other groups (P < 0.05). When we evaluated the association between the serum CRP level and severity of OSAS, CRP levels were positively correlated with AHI in OSAS patients (r = 0.61, P < 0.001) OSAS, as a marker of inflammation and cardiovascular risk, is associated with elevated levels of CRP. According to these results, the link between cardiovascular morbidity and OSAS may be explained by the coexistence of other cardiovascular risk factors such as circulating CRP levels.

Adult↗

PubMed2005

Oral appliance therapy for obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a common disorder characterized by repetitive, complete or partial closure of the upper airway during sleep, resulting in sleep fragmentation and oxygen desaturation. The disorder causes significant morbidity, particularly in terms of impairment of daytime functioning and the impact this has on quality of life. There is also evidence that links OSA to long-term cardiovascular morbidity, including hypertension, myocardial infarction, and stroke, and increased risk of motor vehicle accidents. There is clear evidence that effective treatment of OSA provides major benefit to patients. Nasal continuous positive airway pressure (CPAP) is the current treatment of choice, but its cumbersome nature makes tolerance and compliance less than optimal. This gives rise to the need for other alternatives that are equally effective, but more tolerable. There is growing interest in the use of oral appliances to treat snoring and OSA. The rationale is that advancement of the mandible and tongue impacts positively on upper airway caliber and function. There are many such types of appliances, and they have potential advantages over CPAP in that they are unobtrusive, make no noise, do not need a power source, and are potentially less costly. There is a growing evidence base to support the use of oral appliances in the management of OSA. Recent evidence from randomized controlled trials indicates that oral appliance therapy is effective in controlling OSA in up to 50% of patients, including some patients with more severe forms of OSA. This is associated with a significant improvement in symptoms, including snoring and daytime sleepiness. This evidence is strong for short term, and emerging for long-term treatment of OSA with oral appliances. Whilst direct comparisons with CPAP indicate the superiority of CPAP overall, similar outcomes between the two treatments appear to be achieved in a substantial subgroup of patients. Patient acceptance has, in general, been in favor of oral appliances. Notwithstanding the expanding role of oral appliance therapy, there are a number of limitations that are yet to be overcome. Key issues include the inability to reliably predict treatment outcome, the apparent need for an acclimatization period to attain maximal efficacy of treatment, uncertainty about selection of the appropriate 'dosage' of mandibular advancement required to control OSA in the individual patient, uncertainty about the influence of appliance design on treatment outcome and adverse effects, adherence to treatment, and potential long-term complications of therapy. These issues require resolution before oral appliance therapy can surpass CPAP as first-line treatment for OSA.

Continuous Positive Airway Pressure↗

PubMed2006

Dentofacial characteristics of Chinese obstructive sleep apnea patients in relation to obesity and severity.

OBJECTIVE: To evaluate dentofacial characteristics in relation to obesity and degree of severity of obstructive sleep apnea (OSA) in male Chinese patients and to elucidate the relationship between demographic parameters (age, body weight, height, and body mass index [BMI]) cephalometric parameters and OSA in these subjects. MATERIALS AND METHODS: Lateral cephalograms of 121 Chinese male patients in natural head posture were obtained. Based on BMI value, the patients were divided into three groups. Based on apnea-hypopnea index (AHI) value, the patients were divided into a mild-to-moderate and a severe group. RESULTS: The hyoid position and soft palate length were significantly different among the three obesity groups. Soft palate length was significantly longer (P < .01) in the severe OSA group than in the mild-to-moderate OSA group. Tongue base was significantly more inferiorly placed (P < .05) in the severe OSA group than in the mild-to-moderate OSA group. Craniocervical extension was significantly increased (P < .05) in the severe OSA group. Statistically significant differences were found among the three obesity groups in mandibular length, mandibular body length, maxillary length, anterior cranial base length, and overbite. The multiple stepwise linear regression analysis identified body weight, lower posterior facial height, mandibular body length, craniocervical extension, and sella-hyoid distance as the significant predictive variables for AHI. CONCLUSIONS: This study revealed the existence of craniofacial and upper airway soft tissue differences in relation to obesity and severity of OSA among male Chinese OSA patients. Body weight and certain cephalometric parameters were significant predictors of OSA in Chinese male subjects.

Adult↗

PubMed1997

Vocal tract resonance characteristics of adults with obstructive sleep apnea.

Vocal tract acoustic resonance was evaluated in a group of 10 untreated adult males with diagnosed obstructive sleep apnea (OSA) syndrome compared to 10 non-OSA adult males. Subjects were required to prolong the vowels /i/, /u/ and /a/, which were subsequently submitted to acoustic analysis of formant frequency and formant bandwidth. Results of the formant frequency analysis indicated lower formant values among the OSA group compared to the non-OSA group, for each vowel type. The lower formant frequencies among the OSA group were attributed to greater vocal tract length compared to non-OSA speakers. The corresponding formant bandwidths for each vowel produced by the OSA group were significantly wider compared to the non-OSA group. The wide formant bandwidths were interpreted to reflect significantly greater vocal tract damping in the OSA subjects, resulting from either excessive vocal tract tissue compliance or general size differences in the length and cross-sectional area of the vocal tract. Discussion focuses on the potential applications of acoustic analysis to aid in the diagnosis and follow-up treatment of OSA.

Adult↗

PubMed1998

Obstructive sleep apnea due to endogenous testosterone production in a woman.

Obstructive sleep apnea (OSA) is a common condition characterized by snoring, recurrent episodes of cessation of breathing (obstructive apneas), disrupted sleep, and excessive daytime somnolence. Associated serious complications are hypertension, increased risk of heart disease, stroke, and increased susceptibility to industrial and motor vehicle accidents. OSA is considerably more common in men than in women. In postmenopausal women, the incidence of OSA increases. These factors suggest that reproductive hormones have a role in the cause of OSA. Treatment with testosterone has been reported to cause OSA in men, and exogenous androgen administration has been reported to cause OSA in one woman. In a review of the English literature, we found no previous reports of OSA that was induced by endogenous testosterone in women. Herein we describe a nonobese 70-year old woman with clinically significant OSA and a benign testosterone-producing ovarian tumor. After successful removal of the tumor, her OSA resolved, and her testosterone level normalized. This unique case supports the theory of male hormonal (testosterone) influence in the OSA syndrome.

Aged↗