阻塞性睡眠呼吸暂停低通气综合征患者颈围、腹围及其相关性研究

目的探讨OSAHS患者颈围、腹围以及颈围和腹围的相关关系。方法收集经多导睡眠监测确诊为OSAHS患者80例,单纯打鼾患者41例,测量2组患者的颈围和腹围,并记录一般情况（包括性别、年龄、身高、体质量）,分析OSAHS患者颈围和腹围及其相关性。结果与单纯打鼾组患者相比,OSAHS患者颈围和腹围均明显增大（P〈0．01）。与单纯打鼾组比较,重度0sAHs组颈围明显增大（P〈0．01）,轻中度OsAHS组颈围较单纯打鼾组有增大趋势,但差异无统计学意义（P〉0．05）;与轻中度OSAHS组比较,重度0sAHs组颈围明显增大（P〈o．01）。与单纯打鼾组比较,重度0sAHs组腹围明显增大（P〈0．01）,轻中度OsAHs组腹围较单纯打鼾组增大（P〈0．05）;与轻中度OSAHS组比较,重度OSAHS组腹围明显增大（P〈O．01）。颈围与体质量指数（BMI）、腹围、身高、体质量、睡眠呼吸紊乱指数（AHI）和最长呼吸暂停时间呈显著正相关（P〈0．01）;颈围与年龄呈负相关（P〈O．05）;颈围与最低血氧饱和度呈显著负相关（P〈0．01）。腹围与BMI、颈围、体质量、AHI和最长呼吸暂停时间呈显著正相关（P〈0．01）;腹围与最低血氧饱和度呈显著负相关（P〈0．01）;腹围与年龄、身高无明显相关（P〉O．05）。结论OSAHS患者颈围和腹围均明显增大,颈围与腹围呈显著正相关关系。     

Prevalence and predictive factors of sleep apnoea syndrome in type 2 diabetic patients

AimThis study aimed to assess the prevalence and characteristics of sleep apnoea syndrome (SAS) in patients hospitalized for poorly controlled type 2 diabetes.MethodsAn overnight ventilatory polygraphic study was systematically performed in 303 consecutive patients.ResultsOverall, 34% of these patients had mild SAS, as defined by a respiratory disturbance index (RDI) of 5–15; 19% had moderate SAS (RDI: 16–29) and 10% had severe SAS (RDI ≥ 30). The SAS was obstructive in 99% of the apnoeic patients. The percentage of patients with excessive daytime sleepiness (Epworth sleepiness scale > 10), fatigue or nocturia did not significantly differ among patients with severe, moderate or mild SAS versus non-apnoeic patients. The percentage of patients who snored was significantly higher in patients with severe or moderate SAS versus non-apnoeic patients. HbA_1c, duration of diabetes and the prevalences of microalbuminuria, retinopathy and peripheral neuropathy did not significantly differ among patients with severe, moderate or mild SAS versus non-apnoeic patients. However, patients with severe or moderate SAS had significantly higher values for body mass index, waist circumference and neck circumference than non-apnoeic patients.ConclusionIn type 2 diabetic patients with poor diabetic control, obstructive SAS is highly prevalent and related to abdominal obesity, and should be systematically screened for, as it cannot be predicted by the clinical data.     

Sleep apnoea in treated acromegaly: relative frequency and predisposing factors

OBJECTIVES Sleep apnoea is common in active acromegaly. It is associated with increased morbidity and mortality but can be treated effectively. The objective of this study was to determine the largely unknown relative frequency of, and the predictive factors for, sleep apnoea in treated acromegalic patients. DESIGN Retrospective cohort study. SETTING Tertiary referral hospital. PATIENTS Fifty-four of 100 patients with treated acromegaly. If sleep apnoea had been diagnosed before acromegaly, the patient was excluded. MEASUREMENTS Sleep studies (using the MESAM-4 device measuring oxyhaemoglobin saturation, heart rate, snoring sounds and body position to determine presence and severity of sleep apnoea); GH and IGF-I levels; body mass index, neck and index-finger circumference; daytime symptoms of sleep apnoea, duration of acromegaly before treatment, shoe and neck-size difference since beginning of acromegaly; age, sex and treatment modes of acromegaly. RESULTS The relative frequency of sleep apnoea was 39% in the 54 patients with sleep studies and at least 21% in the entire study population of 100 patients. In patients with sleep apnoea, statistically significant higher values were observed for GH (P = 0.002), IGF-I (P = 0.029), age (P = 0.014) and neck circumference (P = 0.016). An index-finger circumference of ≥8.5 cm was associated with a significantly higher desaturation index (P = 0.012, Mann–Whitney Itest). Adenomectomy had been performed significantly less frequently in patients with sleep apnoea (P < 0.001, χ² test). The body mass index was non-significantly higher in the patients with sleep apnoea. CONCLUSIONS The relative frequency of sleep apnoea in patients with treated acromegaly is at least 21%. Parameters of predictive value for the presence of sleep apnoea in this population are neck and index-finger circumference as measures of soft tissue hypertrophy, age, GH and IGF-I levels, and whether or not operative therapy was applied.     

Sleep-related breathing disorders, loud snoring and excessive daytime sleepiness in obese subjects

OBJECTIVE: To investigate the prevalence of sleep breathing disorders, loud snoring and excessive daytime sleepiness in a group of obese subjects, and to identify the predictors of obstructive sleep apnea (OSA) severity in these patients. SUBJECTS: A total of 161 consecutive obese patients (body mass index (BMI)> or =30.0 kg/m(2)), ranging between 30.0 and 67.3, represented by 57 men and 104 women, aged 16-75 y. Forty (15 men and 25 women) age-matched (20-70 y) nonobese (BMI<27 kg/m(2)) volunteers were also recruited for the study. MEASUREMENTS: Respiratory function parameters, nocturnal sleep quality (evaluated by a specific questionnaire), nocturnal hypoventilation and OSA (evaluated by night polysomnography) were examined in all subjects. Anthropometric parameters (neck circumference, waist circumference, waist-to-hip ratio) were also investigated. RESULTS: Eighty-three obese patients (51.5% of the obese group) had a respiratory disturbance index (RDI)> or =10, corresponding to a moderate or severe sleep apnea. In particular, 24.8% (40/161), ie a quarter of all obese patients, were affected by severe OSA and this alteration was present in 42.1% of obese men (24/57) and in 15.4% (16/104) of obese women. When a stepwise multiple regression analysis was performed, neck circumference in men and BMI in women were shown to be the strongest predictors of sleep apnea. Twenty-nine percent of all obese subjects (40.3% of men and 23.1% of women) showed nocturnal hypoventilation; however, it was present as a unique breathing alteration in only 5% of the obese population. The percentage of patients having excessive daytime sleepiness was significantly higher than in nonobese subjects, even when only nonapneic obese patients were considered (P<0.001). CONCLUSION: This study shows that OSA is present in more than 50% of a population of obese patients with a mean BMI higher than 40.0, this percentage being much higher than that commonly reported in previous studies, particularly in women. Neck circumference in men and BMI in women seem to be the strongest predictors of the severity of OSA in obese patients. Nocturnal hypoventilation seems to be present in more than 29% of a severe obese population. Moreover, this study indicates that morbid obesity can be associated with excessive daytime sleepiness even in the absence of sleep apnea.     

Obstructive sleep apnoea among HIV patients

The development of body weight gain and lipodystrophy due to antiretroviral therapy may lead to disturbances in sleep, particularly the obstructive sleep apnoea (OSA) syndrome. A retrospective review of the medical records of consecutively identified HIV-infected subjects who were diagnosed with OSA by overnight polysomnography between January 1, 2003 and December 31, 2004 was performed. Twelve HIV-infected subjects with OSA confirmed by polysomnography (total apnoea/hypopnoea index > or = 5) were identified. Daytime somnolence, fatigue, and snoring were the most common symptoms identified. Eleven (92%) subjects were overweight/obese, and seven (58%) had lipodystrophy. Eleven (92%) had a neck size > or =40.0 cm. Increased neck circumference, overweight or obese body mass index, and lipodystrophy are therefore potential risk factors for OSA among HIV patients. Clinicians caring for HIV patients with these characteristics should inquire about daytime somnolence, fatigue, and snoring and consider evaluation for a sleep-related disorder such as OSA. Overnight polysomnography can aid in the diagnosis of sleep disturbances.     

打鼾与睡眠呼吸暂停低通气综合征的关系研究

目的调查打鼾患者睡眠呼吸暂停低通气综合征的患病率,探讨打鼾与夜间低氧的关系。方法采用流行病调查的方法对克拉玛依市天山社区1121例35岁以上常住居民进行人户睡眠问卷调查及夜间呼吸血氧监测。结果鼾症高危组与鼾症低危组在颈围、腹围、氧减指数、夜间最低氧饱和度、呼吸暂停指数等方面比较差异有统计学意义（P均〈0．05）。鼾症组与非鼾症组在体重指数、颈围、腹围、氧减指数、夜间最低氧饱和度、呼吸暂停指数、低通气指数比较差异有统计学意义（P均〈0．01）。鼾症高危组与低危组间睡眠呼吸暂停低通气综合征的发生率比较差异有统计学意义（P〈0．05）。结论打鼾与睡眠呼吸暂停低通气综合征、夜间低氧相关,睡眠呼吸暂停低通气综合征与鼾症分级有关,颈围和腹围是打鼾和睡眠呼吸暂停低通气综合征的危险因素。     

Cephalometric assessment of craniofacial morphology in Chinese patients with obstructive sleep apnoea

OBJECTIVE: To compare the differences in craniofacial morphology in Chinese patients with and without obstructive sleep apnoea (OSA). METHOD: We performed lateral cephalometric radiographs on 94 consecutive patients (77 males) referred with snoring or other symptoms suggestive of OSA for polysomnography (PSG). Significant OSA was defined as an apneoa-hypopnoea index (AHI) > or = 10/h of sleep on overnight PSG. The cephalometric data were compared between those with and without significant OSA. RESULTS: (mean +/- SD) There were 69 (56 males) with significant OSA with mean age 53 +/- 12 years, body mass index (BMI) 28.6 +/- 5.0 kg/m2, AHI 36.5 +/- 20.6/h, and minimum SaO2 76 +/- 14%. There were 25 controls (21 males) without significant OSA with similar age and BMI. The mandibular plane to hyoid bone distance (MPH) and the perpendicular distance from hyoid bone to the line connecting C3 vertebra and retrognathion (HHI) were significantly longer in the OSA patients. The angle measurement from sella to nasion to point A (SNA) was smaller in the OSA group. MPH distance was the only independent variable for significant OSA with an odds ratio of 3.47 (95% CI 1.39-8.66). Abnormalities of the MPH and SNA were more marked in the OSA patients with BMI > or = 30 kg/m2. CONCLUSIONS: Significant differences in craniofacial morphology are noted between OSA patients and non-apnoeic controls. An inferiorly positioned hyoid bone and a retropositioned maxilla may predispose obese patients to more severe OSA.     

阻塞性睡眠呼吸暂停低通气综合征患者血清脂联素水平的研究

目的 探讨血清脂联素在阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者体内的变化。方法 选择伴有肥胖的OSAHS患者71例(肥胖OSAHS组)、不伴肥胖的OSAHS患者21例(非肥胖OSAHS组)、单纯性肥胖者26例(单纯性肥胖组)和健康成人22例(正常对照组)。其中肥胖OSAHS组和单纯性肥胖组的体重指数(BMI)均大于25,两组间BMI差异无显著性。肥胖OSAHS组又进一步分为轻度(26例)、中度(22例)和重度(23例)。均接受多导睡眠仪监测和放射免疫法测定血清脂联素水平。结果 正常对照组血清脂联素水平[(8.9±0.6)mg/L]显著高于单纯性肥胖组[(7.1±1.3)mg/L](P<0.05)、非肥胖OSAHS组[(5.4±0.6)mg/L,P<0.01]和肥胖OSAHS组[(5.0±1.0)mg/L,P<01]。与单纯性肥胖组的血清脂联素水平相比,无论肥胖OSAHS组或非肥胖OSAHS组均显著降低,差异有显著性(P<0.05)。肥胖OSAHS组与非肥胖OSAHS组的血清脂联素水平相比,差异无显著性(P>0.05)。肥胖OSAHS组与单纯性肥胖组的分析显示:血清脂联素水平与呼吸暂停低通气指数(AHI)(r=-0.78,P<0.01)、BMI(r=-0.21,P<0.05)、腰围(r=-O.36,P<0.01)和颈围呈负相关(r=-0.42,P<0.01),与最低脉搏血氧饱和度呈正相关(r=0.48,P<0.01)。结论 OSAHS患者中血清脂联素水平较正常对照和单纯肥胖者更低,除了腰围和颈围的因素     

Nocturnal hypoxia and sleep apnoea in asymptomatic obese men

A disorder of breathing during sleep with a fall in arterial oxygen saturation (%SaO2) and apnoea is reported in association with obesity. In obese women an increased severity of oxygen desaturation and the appearance of sleep apnoea is often seen after the menopause whereas the factors influencing sleep-breathing patterns in obese men are uncertain. We investigated this by studying respiration during sleep in 20 asymptomatic obese men (mean wt 125 kg, age range 18-59 y) and 20 control men of normal weight (mean wt 67 kg, age range 19-67 y). In the obese men the mean awake %SaO2 measured in the supine position was significantly less than controls (obese 95 +/- 0.4, controls 97 +/- 0.2, P less than 0.01) and a greater fall in %SaO2 occurred in this group during sleep (mean asleep %SaO2 obese 90.5 +/- 0.9, controls 96 +/- 0.2, P less than 0.01). In addition, the minimum asleep %SaO2 was significantly less in the obese (mean minimum %SaO2 obese 75 +/- 3, controls 93 +/- 0.9, P less than 0.001). Sleep apnoea was uncommon and infrequent in the controls but was seen in nine obese men and was frequent throughout the night in seven of them. In the obese group increasing age and increasing obesity were not significantly correlated with an increased severity of nocturnal oxygen desaturation. We conclude that disordered sleep-breathing with marked oxygen desaturation and apnoea is a common finding in extremely obese men of all ages and suggest that this results from the mechanical impedence of breathing due to abdominal adipose tissue combined with abnormal central respiratory control.     

High prevalence of previously unknown subclinical hypothyroidism in obese patients referred to a sleep clinic for sleep disordered breathing

BACKGROUND AND AIM: To evaluate the prevalence of previously unknown hypothyroidism in adult male and female patients with a wide range of body mass index (BMI) values, referred to a Sleep Clinic because of sleep disordered breathing (SDB). METHODS AND RESULTS: Serum concentrations of thyroid stimulating hormone (TSH) and free thyroxin (fT4), as well as forced vital capacity (FVC), PaO2, PaCO2, the Epworth sleepiness scale (ESS), respiratory disturbance index (RDI), loud snoring, and the percentage of total sleep time (TST) with <90% oxyhemoglobin saturation (TST(saO2<90%)) were measured in 78 overweight and obese adult subjects with no previous diagnosis of hypothyroidism (age: 18-72 years). The prevalence of previously undiagnosed subclinical hypothyroidism in the population as a whole was 11.5%. BMI, TSH and ESS were significantly higher in the hypothyroid than the euthyroid subjects, but there was no significant between-group difference in RDI, TST(saO2<90%) or the other investigated variables, including the prevalence of obstructive sleep apnea (OSA). Among the hypothyroid individuals, BMI, neck circumference, ESS, RDI and TST(Sao2<90%) were significantly higher in those with than in those without OSA. Furthermore, there was a clear trend towards a lower FVC% and higher snoring score in the OSA patients. CONCLUSIONS: Our results demonstrate a higher prevalence of hypothyroidism than that commonly reported in overweight and obese individuals referred to a Sleep Clinic for polysomnography because of SDB, thus suggesting that thyroid function should be evaluated in all obese patients suffering from SDB despite economic concerns.     

The impact of obesity on oxygen desaturation in patients with sleep apnea/hypopnea syndrome]

We performed a cross-sectional investigation on the impact of obesity on clinical manifestations in patients with obstructive sleep apnea/hypopnea syndrome (SAHS). The subjects were 87 patients who underwent overnight polysomnography with an apnea/hypopnea index (AHI) of 15/h or more. We divided these patients into non-obese (N) and obese (O) groups based on the median value of the body mass index (BMI), 27 kg/m2. Subjective symptoms, sleep quality and AHI were similar in both groups, but every parameter related to oxygen desaturation was worse in group O than in group N. There was no difference in the mean duration of apnea events between the two groups. The rate of fall in oxygen saturation during apnea events was highly correlated to the BMI (r = 0.72; p < 0.00001). Accordingly, we concluded that profound desaturation in group O is due to a rapid fall in oxygen saturation during apnea events compared with group N. Anthropometric measurements revealed that the rate of fall in oxygen saturation was more related to abdominal circumference (AC) than the neck circumference (NC), which is contrasted with the finding that AHI was more related to NC than AC. This fact suggests that abdominal obesity may deteriorate oxygenation during apnea events and may therefore aggravate the risk of cardiovascular disease in patients with SAHS.     

Exhaled breath markers in patients with obstructive sleep apnoea

The objectives of the present study were to assess the level of exhaled breath markers indicating airway inflammation and oxidative stress in patients with obstructive sleep apnoea syndrome (OSAS) in comparison with non-apnoeic (obese and non-obese) subjects and investigate whether therapy with continuous positive airway pressure (CPAP) can modify them. The design was a retrospective observational study, set in Evgeneidio Hospital. Twenty-six OSAS patients and nine obese and 10 non-obese non-apnoeic subjects participated in this study. We measured nasal nitric oxide (nNO), exhaled nitric oxide (eNO), exhaled carbon monoxide (eCO) in exhaled breath, and 8-isoprostane, leukotriene B(4) (LTB(4)), nitrates, hydrogen peroxide (H(2)O(2)), and pH in exhaled breath condensate (EBC) before and after 1 month of CPAP therapy. The levels of eNO and eCO were higher in OSAS patients than in control subjects (p < 0.05). Nasal NO was higher in OSAS patients than in obese controls (p < 0.01). The level of H(2)O(2), 8-isoprostane, LTB(4), and nitrates were elevated in OSAS patients in comparison with obese subjects (p < 0.01). Conversely, pH was lower in OSAS patients than in non-apnoeic controls (p < 0.01). One month of CPAP therapy increased pH (p < 0.05) and reduced eNO (p < 0.001) and nNO (p < 0.05). Apnea/hypopnoea index was positively correlated with 8-isoprostane (r = 0.42; p < 0.05), LTB(4) (r = 0.35; p < 0.05), nitrates (r = 0.54; p < 0.001), and H(2)O(2) (r = 0.42; p < 0.05). Airway inflammation and oxidative stress are present in the airway of OSAS patients in contrast to non-apnoeic subjects. Exhaled breath markers are positively correlated with the severity of OSAS. One-month administration of CPAP improved airway inflammation and oxidative stress.     

Sleep, blood pressure and obesity in 22,389 New Zealanders

Aim: To determine the relationship of sleep disorders with blood pressure and obesity in a large, relatively healthy, community‐based cohort. Methods: A cross‐sectional study was undertaken using data from 22 389 volunteer blood donors in New Zealand aged 16–84 years. Height, weight, neck circumference and blood pressure were measured directly, and data on sleep and other factors were ascertained using a validated self‐administered questionnaire. Results: Even in a relatively young, non‐clinical cohort, lack of sleep (34%), snoring (33%), high blood pressure (20%) and obesity (19%) are common. After adjusting for relevant confounders, participants at high risk of sleep apnoea had double the odds of having high blood pressure but only in participants over 40 years. Very low and high quantities of sleep are also associated with high blood pressure. Even after controlling for neck circumference, self‐reported sleep apnoea, sleep dissatisfaction and low amounts of sleep are associated with a higher body mass index. Conclusions: Obesity and hypertension have significant associations with a variety of sleep disorders, even in those less than 40 years of age and after adjusting for a wide range of potential confounders.     

Increased central adiposity in morbidly obese patients with obstructive sleep apnoea

Background: With the growing epidemic of obesity, few data are available regarding adipose distribution and the severity of sleep apnoea. Our aim was to measure precisely adipose distribution with dual‐energy X‐ray absorptiometry (DXA) in a morbidly obese population with and without obstructive sleep apnoea (OSA). Methods: Morbidly obese female subjects without a history of OSA underwent overnight polysomnography and DXA analysis. Subject demographics, DXA variables, serum laboratory markers and physical exam characteristics were compared between individuals with and without OSA. Results: For the study population (n= 26), mean body mass index (BMI) was 45.9 ± 7.8 kg/m²; mean age was 47.5 ± 10.2 years and all were female. The central adiposity ratio (CAR) was higher in individuals with OSA (apnoea–hypopnoea index > 5) than those without OSA (1.1 ± 0.05 vs 1.0 ± 0.04; P= 0.004). No difference was observed in Epworth Sleepiness Scale scores, body mass index (BMI) or neck circumference between groups. Conclusions: OSA is associated with increased central adipose deposition in patients with a BMI of >40 kg/m². These data may be helpful in designing future studies regarding the pathophysiology of OSA, and potential treatment options.     

孕期打鼾对不同妊娠期妇女的影响

目的 探讨孕期打鼾对不同妊娠期妇女的病理影响.方法 选择2006年1月至2008年2月在温州医学院附属第二医院产科门诊建卡登记并分娩的孕妇601例,年龄范围19～41岁,于妊娠第13周、28周及分娩前问卷调查睡眠打鼾情况、测量孕妇生理生化指标,记录妊娠期并发症和妊娠结局.根据妊娠时间及打鼾情况,分为打鼾组与非打鼾组,并将打鼾组细分为孕早期打鼾组、孕中期打鼾组、孕晚期打鼾组.结果 与非打鼾组比较,打鼾组孕妇体重指数、腹围及颈围在孕早、中、晚期均明显增加,差异有统计学意义(均P<0.05).臀围及收缩压在孕早期无变化,孕中期、晚期明显增加(P<0.05),舒张压在孕早、中期无变化(P>0.05),孕晚期明显增加,差异有统计学意义(P<0.05).打鼾组内早产发生率比较差异无统计学意义(P<0.05).孕早、中期打鼾组剖宫产及妊娠高血压综合征发生率均明显高于非打鼾组,差异有统计学意义(P<0.05),孕晚期打鼾组和非打鼾组比较,差异无统计学意义(P>0.05),孕早期和孕中期打鼾组比较无统计学差异,但均高于孕晚期打鼾组,差异有统计学意义(P<0.05).孕期打鼾是妊娠高血压综合征发生的危险因素,孕早期、中期打鼾是早产和剖宫产的危险因素.各孕期打鼾组孕妇妊娠高血压综合征、早产、剖宫产发生率较非打鼾组均明显增加,差异有统计学意义(均P<0.05),打鼾组间两两比较差异无统计学意义(P>0.05).结论 孕期打鼾使孕妇生理特点发生变化,妊娠高血压综合征、早产、剖宫产的发生率增加,应重视打鼾孕妇的围产期保健.     

The relationship between neck circumference, radiographic pharyngeal anatomy, and the obstructive sleep apnoea syndrome

We have studied the predictive importance of neck circumference, obesity, and several radiographic pharyngeal dimensions for obstructive sleep apnoea (OSA), in 66 patients. OSA was quantified as the mean hourly number of greater than 4% dips in arterial oxygen saturation during sleep. Neck circumference (correlation coefficient (r) = 0.63, 95% confidence interval (C.I.) 0.46-0.76), obesity index (r = 0.54, 95% C.I. 0.39-0.69), hyoid position (r = 0.40, 95% C.I. 0.17-0.59), soft palate length (r = 0.31, 95% C.I. 0.08-0.51), and hard palate-to-spine angle (r = 0.29, 95% C.I. 0.04-0.49), correlated significantly with saturation dips in single regression analysis. In stepwise multiple linear regression analysis (saturation dip rate as the dependent variable), only neck size and retroglossal space were significant independent correlates (total r2 = 0.42, 95% C.I. 0.22-0.61, p less than 0.0001). We conclude that the relationships between general obesity, hyoid position, soft palate length, and OSA are probably secondary to variation in neck circumference.     

Obstructive sleep apnea syndrome in morbid obesity: effects of intragastric balloon

STUDY OBJECTIVES: In obese patients, obstructive sleep apnea syndrome (OSAS) is attributed to a reduction in pharyngeal cross-sectional area due to peripharyngeal fat deposition. The effect of weight loss on the size of the upper airways of obese subjects is still unknown. We analyzed the pharyngeal cross-sectional area before and after weight loss in morbidly obese patients with OSAS. DESIGN, SETTING, AND SUBJECTS: A group of 17 middle-aged, morbidly obese men was evaluated by anthropometry and cardiorespiratory sleep studies before and after weight loss obtained by insertion of an intragastric balloon. The pharyngeal cross-sectional area was measured by acoustic pharyngometry. RESULTS: The mean (+/- SD) body mass index was 55.8 +/- 9.9 kg/m2 at baseline and 48.6 +/- 11.2 kg/m2 at the time of balloon removal (6 months after insertion) [p < 0.001]. At baseline, patients had visceral obesity, large necks, and severe OSAS. Weight loss was associated with a significant mean reduction of waist circumference (156.4 +/- 17.6 vs 136.7 +/- 18.4 cm, respectively; p < 0.001), sagittal abdominal diameter (37.8 +/- 3.0 vs 32.3 +/- 4.0 cm, respectively; p < 0.001), and neck circumference (51.1 +/- 3.7 vs 47.9 +/- 4.3 cm, respectively; p < 0.001). Moreover, weight loss induced a nearly complete resolution of OSAS (apnea-hypopnea index, 52.1 +/- 14.9 vs 14.0 +/- 12.4 events/h, respectively; p < 0.001). At baseline, obese patients had significantly lower pharyngeal cross-sectional areas compared to a group of 20 nonobese male control subjects, both in the upright and supine position, at different levels of the pharynx. In obese patients, the weight loss induced by the positioning of the intragastric balloon was associated with an increase in the size of the upper airway passage. After weight loss, both the mean pharyngeal cross-sectional area and the area at glottis level were still lower in obese subjects than in nonobese subjects; however, the pharyngeal cross-sectional area at the oropharyngeal junction was similar in the two groups. CONCLUSIONS: Morbidly obese men with OSAS have a reduced pharyngeal cross-sectional area. A weight reduction of about 15% of baseline body weight may substantially increase the pharyngeal cross-sectional area and substantially improve the severity of OSAS in morbidly obese subjects with sleep apnea.     

Apnoea characteristics across the night in severe obstructive sleep apnoea: influence of body posture.

Several studies have reported changes in apnoea characteristics across the night in patients with obstructive sleep apnoea (OSA). However, the effect of body posture on these changes has not been evaluated. The purpose of this study was to assess how body posture influences sleep apnoea characteristics across the night in severe OSA. Polysomnograms of 30 patients with severe OSA who had > or = 30 apnoeic episodes in the lateral position and 30 in the supine position during Stage 2 sleep, in the early, middle and late sleep periods were analysed. For each of the 30 events in each body position, the following variables were evaluated: apnoea duration; minimum saturation; change in saturation; duration of arousal; maximum snoring loudness and change in cardiac frequency. Although at any time during the night, apnoeas in the supine posture were more severe than those in the lateral position, a time effect across the night was found only for apnoea duration, change in cardiac frequency and duration of arousal. Body position did not affect the time trend for these variables across the night. The best fit for the changes of these three variables across the night was a quadratic time trend. It was concluded that in severe obstructive sleep apnoea during Stage 2 sleep, body position does not significantly affect the time trends of apnoea characteristics across the night. These data provide support for the participation of sleep-dependent mechanisms (homeostatic and circadian) in the determination of apnoea characteristics across the night.     

Clinical, anthropometric and upper airway anatomic characteristics of obese patients with obstructive sleep apnea syndrome

BACKGROUND: Obese subjects are at increased risk of developing obstructive sleep apnea syndrome (OSAS). However, the individual role of local (i.e., upper airway-related) and general (clinical and whole-body anthropometric) characteristics in determining OSAS in obese patients is still controversial. OBJECTIVES: To contrast the clinical, anthropometric and upper airway anatomical features of obese subjects presenting or not presenting with OSAS. METHODS: Thirty-seven obese (BMI > or =30 kg/m(2)) males with OSAS and 14 age- and gender-matched obese controls underwent clinical and anthropometric (BMI, waist-to-hip ratio and neck circumference) evaluation. In a subgroup of subjects (18 and 11 subjects, respectively), magnetic resonance imaging (MRI) during wakefulness was used to study the upper airway anatomy. RESULTS: OSAS patients showed significantly higher BMI, waist-to-hip ratio and neck circumference as compared to controls (p < 0.05). They also referred to nonrepairing sleep, impaired attention, and previous car accidents more frequently (p < 0.05). The transversal diameter of the airways (TDAW) at the retroglossal level by MRI was found to be an independent predictor of the presence and severity of OSAS (p < 0.05). Parapharyngeal fat increase, however, was not related to OSAS. A TDAW >12 mm was especially useful to rule out severe OSAS (apnea-hypopnea index >30, negative predictive value = 88.9%, likelihood ratio for a negative test result = 0.19). CONCLUSIONS: MRI of the upper airway can be used in association with clinical and anthropometric data to identify obese males at increased risk of OSAS.