Role of hypoxic drive in regulation of postapneic ventilation during sleep in patients with obstructive sleep apnea

To elucidate the role of chemoresponsiveness in determining postapneic ventilation in sleep-disordered periodic breathing, we measured ventilatory response associated with apnea-induced arterial oxygen desaturation during sleep and compared it with the awake hypoxic ventilatory response (HVR) in 12 male patients with obstructive sleep apnea (OSA). Awake HVR was measured at a slight hypocapnic level (end-tidal PCO2 = 37 +/- 1 mm Hg, mean +/- SEM), and separately at a PCO2 of 45 mm Hg. During non-REM sleep both the ventilatory rate (VE) and the average respiratory frequency (f) in the ventilatory phase between apneic episodes were inversely correlated with the nadir of arterial oxygen saturation (nSaO2) produced by the preceding apneic phase in all patients (VE versus nSaO2; r = -0.74 +/- 0.03, mean +/- SEM; f versus nSaO2, r = -0.56 +/- 0.04). The average tidal volume (VT) also was correlated with nSaO2 in 10 of the patients (r = -0.56 +/- 0.05). During REM sleep VE was correlated with nSaO2 in 11 patients (r = -0.75 +/- 0.03, p less than 0.02). The response of VE to nSaO2 (delta VE/delta nSaO2) varied widely among the patients (non-REM, 0.52 to 2.16; REM, 0.29 to 1.44 L/min/%) and was significantly lower during REM than non-REM sleep (p less than 0.01). The value of delta VE/delta nSaO2 during both non-REM and REM sleep was correlated with awake HVR at an end-tidal PCO2 of 45 mm Hg (non-REM, r = 0.83, p less than 0.02; REM, r = 0.76, p less than 0.05) but not with that at the hypocapnic level.(ABSTRACT TRUNCATED AT 250 WORDS)     

11O例老年阻塞性睡眠呼吸暂停低通气综合征患者多导睡眠监测及相关分析

目的 加深对老年患者阻塞性睡眠呼吸暂停低通气综合征(obstructive sleep apneahypopnea syndrome,OSAHS)特点的认识,提高老年OSAHS诊治水平.方法 对我院睡眠呼吸障碍与鼾症诊治中心诊断的110例老年OSAHS患者的整夜多导睡眠图(PSG)监测资料进行回顾性分析,应用SPSS 18.0统计软件对患者的一般情况、睡眠结构、呼吸暂停和低通气情况、氧减饱和情况以及各指标间可能的相关关系进行统计分析.结果老年OSAHS患者中位快动眼相(rapid eye movement,REM)和非快动眼相(NREM)睡眠时间分别占2.17%和76.73%;中位觉醒指数为45.60次/h.呼吸暂停最长时间为(51.94±22.06)s,中位呼吸暂停平均时间为22.50 s,低通气最长时间为(47.06±12.52)s,低通气平均时间为(21.50±4.63)s.中位呼吸紊乱指数(respiratory disturbance index,RD1)为21.50,RDI 5～20者占46.40%,20～40者占31.80%,＞40者占21.80%.夜间平均血氧饱和度为(93.45±2.81)%,夜间最低血氧饱和度为(76.30±10.50)%,中位氧减饱和指数为31.65次/h.体质指数(BMI)与夜间最低血氧饱和度(r=-0.378,P＜0.01)和夜间平均血氧饱和度(r=-0.355,P＜0.01)呈负相关,与氧减指数呈正相关(r=0.338,P＜0.01);夜间最低血氧饱和度与阻塞性呼吸暂停最长时间(r=-0.47,P＜0.01)、阻塞性呼吸暂停平均时间(r=-0.31 6,P＜0.01)、低通气最长时间(r=-0.293,P＜0.01)和低通气平均时间(r=-0.277,P＜0.01)呈负相关.仰卧位睡眠时中位氧减时间间隔为2.36 min,左侧卧位睡眠时中位氧减时间间隔为11.54 min,右侧卧位睡眠时中位氧减时间间隔为12.45 min,左侧卧位和右侧卧位睡眠时中位氧减时间间隔均长于仰卧位(Z值分别为-6.12和-7.10,均P＜0.01).结论 老年OSAHS患者存在明显的睡眠结构紊乱和睡眠片段化.依据RDI对患者的病情分级,大多数OSAHS患者为轻、中度,但缺氧程度较重,缺氧严重度与BMI和睡眠呼吸事件的持续时间相关,侧卧睡眠时缺氧程度减轻.     

Hypoxemia and hypercapnia during exercise and sleep in patients with cystic fibrosis.

BACKGROUND: In patients with cystic fibrosis (CF), it has been proposed that hypoxemia and hypercapnia occur during episodes of stress, such as exercise and sleep, and that respiratory muscle weakness because of malnutrition may be responsible. METHODS: Pulmonary function, respiratory muscle strength, and nutrition were assessed and correlated with the degree of hypoxemia and hypercapnia during exercise and sleep in 14 patients with CF and 8 control subjects. RESULTS: Despite no differences in maximum static inspiratory pressure (PImax) between the two groups, the CF group developed more severe hypoxemia (minimum oxyhemoglobin saturation [SpO2], 89 +/- 5% vs 96 +/- 2%; p < 0.001) and hypercapnia (maximum transcutaneous CO2 tension [PtcCO2], 43 +/- 6 vs 33 +/- 7 mm Hg; p < 0.01) during exercise. Similarly, during sleep, the CF group developed greater hypoxemia (minimum SpO2, 82 +/- 8% vs 91 +/- 2%; p < 0.005), although CO2 levels were not significantly different (maximum PtcCO2, 48 +/- 7 vs 50 +/- 2 mm Hg). Within the CF group, exercise-related hypoxemia and hypercapnia did not correlate with FEV1, residual volume/total lung capacity ratio (RV/TLC), PImax, or body mass index (BMI). Hypoxemia and hypercapnia during sleep correlated with markers of gas trapping (RV vs minimum arterial oxygen saturation [r = -0.654; p < 0.05]), RV vs maximum PtcCO2 (r = 0.878; p < 0.001), and RV/TLC vs maximum PtcCO2 (r = 0.790; p < 0.01) but not with PImax or BMI. CONCLUSION: Patients with moderately severe CF develop hypoxemia and hypercapnia during exercise and sleep to a greater extent than healthy subjects with similar respiratory muscle strength and nutritional status. Neither respiratory muscle weakness nor malnutrition are necessary to develop hypoxemia or hypercapnia during exercise or sleep.     

Polysomnographic values in children 2-9 years old: additional data and review of the literature

The establishment of normal pediatric polysomnographic parameters is important for both clinical and research interests. Our objectives were to describe respiratory events, paradoxical breathing, periodic limb movements, and sleep architecture of children at the age of peak incidence of obstructive sleep apnea syndrome. We performed a retrospective cross-sectional analysis of a prospective cohort study of 66 children, 2-9 years old, at the Sleep Disorders Center at the Children's Hospital of Philadelphia. Subjects screened by questionnaire underwent a standard polysomnogram. The percent of total sleep time spent in sleep stages 1, 2, 3, 4, and rapid eye movement (REM) were 4 +/- 3%, 44 +/- 10%, 10 +/- 6%, 22 +/- 8%, and 21 +/- 6%, respectively. The arousal and awakening index was 11.2 +/- 4.3/hr. Respiratory events included a central apnea index of 0.08 +/- 0.14/hr, obstructive apnea index of 0.01 +/- 0.03/hr, and obstructive hypopnea index of 0.3 +/- 0.5/hr. The baseline arterial oxygen saturation (SpO2) was 97 +/- 1%, with a nadir of 92 +/- 3%. The index of periodic limb movements in sleep (PLMS) was 1.3 +/- 2.2/hr. Paradoxical breathing appeared significantly more frequent with piezo crystal effort belts (40 +/- 24% of epochs) than with respiratory inductive plethysmography (1.5 +/- 3% of epochs). We describe the occurrence of hypopneas during sleep, arousals and awakenings, and PLMS. We illustrate how different technologies can vary the apparent amount of paradoxical breathing. We also confirm previous data on the frequency distribution of sleep stages, SpO2, and relative rarity of respiratory events in this age group.     

Predicting sleep-disordered breathing in patients with cystic fibrosis

STUDY OBJECTIVES: To examine predictors of sleep-disordered breathing in patients with cystic fibrosis (CF) and moderate-to-severe lung disease using a comprehensive evaluation of both sleep and daytime function. DESIGN: Cross-sectional analysis of sleep studies, lung function, respiratory muscle strength, and evening and morning arterial blood gas measurements in patients with stable CF. A questionnaire addressing sleep quality was administered. Forward stepwise regression analysis was used to identify the parameters that best predict sleep-related desaturation, hypercapnia, and respiratory disturbance. SETTING: Sleep investigation unit and lung function laboratory. PATIENTS: Thirty-two patients with CF and FEV(1) < 65% predicted, in stable clinical condition. Patients were aged 27 +/- 8 years (mean +/- 1 SD) with FEV(1) of 36 +/- 10% predicted, evening PaO(2) of 68 +/- 8 mm Hg, and PaCO(2) of 43 +/- 5 mm Hg. RESULTS: Evening PaO(2) (p < 0.0001) and morning PaCO(2) (p < 0.01) were predictive of the average minimum oxyhemoglobin saturation per 30-s epoch of sleep (r(2) = 0.74; p < 0.0001). Evening PaO(2) (p < 0.001) was predictive of the rise in transcutaneous carbon dioxide (TcCO(2)) seen from non-rapid eye movement (NREM) to rapid eye movement (REM) sleep (r(2) = 0.37; p < 0.001). In addition, there was some relationship between expiratory respiratory muscle strength and the REM respiratory disturbance index (r(2) = 0.22; p < 0.01). CONCLUSION: Evening PaO(2) was found to contribute significantly to the ability to predict both sleep-related desaturation and the rise in TcCO(2) from NREM sleep to REM sleep in this subgroup of patients with CF.     

Morning levels of C-reactive protein in children with obstructive sleep-disordered breathing

Obstructive sleep-disordered breathing is associated with cardiovascular disease in adults, and elevated C-reactive protein (CRP) has been proposed as a link between the two disorders. We hypothesized that children with sleep-disordered breathing have higher CRP values than do control subjects. CRP was measured in 39 children (mean age +/- SD: 6.9 +/- 3.2 years) without snoring (controls) and in 102 children (6.2 +/- 2.2 years) with habitual snoring who underwent polysomnography. No significant differences were found in mean CRP values between control subjects (0.12 +/- 0.16 mg/dl; n = 39) and snorers with an apnea-hypopnea index of less than 1 episode/hour (0.15 +/- 0.26; n = 18), snorers with an index of 1 or more and less than 5 (0.15 +/- 0.26; n = 54), and snorers with an index of 5 or more (0.22 +/- 0.43; n = 30; p > 0.05). There was no correlation between CRP or log-transformed CRP values and apnea-hypopnea index, respiratory movement/arousal index, Sa(O(2)) nadir, oxygen desaturation (>/= 4%) of hemoglobin index, or percentage of sleep time with saturation less than 95% (p > 0.05). Thus, findings of higher CRP values in adults with sleep-disordered breathing and correlations of these values with polysomnography indices were not confirmed in children.     

Prevalence and mechanisms of diurnal hypercapnia in a sample of morbidly obese subjects with obstructive sleep apnoea

It is well known that obstructive sleep apnoea is especially frequent in the morbidly obese. In these subjects diurnal chronic hypercapnia, whose mechanism is still debated, may be present. Our study was performed to evaluate the prevalence and the mechanism of diurnal hypercapnia in the morbidly obese affected by obstructive sleep apnoea. From a population referred to our centre because of suspicion of sleep related breathing disorders, we selected 285 subjects without cardiopulmonary, neuromuscular or endocrinological diseases: 89 (36 M and 53 F, aged 46+/-13 years) had body mass index (BMI) > or = 40 kg m(-2) (MO group: morbidly obese subjects) and 196 (99 M and 97 F, aged 48+/-16 years) had BMI <40 kg m(-2) (NMO group: non-morbidly obese subjects). Then the MO group was divided into three subgroups: normocapnic subjects without obstructive sleep apnoea, normocapnic subjects with obstructive sleep apnoea, hypercapnic subjects with obstructive sleep apnoea; while we found no hypercapnic subject without obstructive sleep apnoea. All subjects underwent anthropometric evaluations and bioelectrical impedance analyses, respiratory function tests and arterial blood gas analysis, a modified version of the Sleep and Healthy questionnaire and a full night polysomnography. Our results showed that hypercapnia (PaCO2 > or = 45 mm Hg) associated with obstructive sleep apnoea [respiratory disturbance index (RDI) > or = 10 h(-1)] was found in 27% of the morbidly obese subjects, but only in 11% of the nonmorbidly obese ones (P<0.01). The comparison among the three subgroups, in which we divided the morbidly obese subjects, shows that those with hypercapnia and obstructive sleep apnoea had significantly more important ventilatory restrictive defects [forced vital capacity (FVC)% of pred 73.27+/-14 81 vs. 82.37+/-16.93 vs. 87.25+/-18.14 respectively; total lung capacity (TLC)% of pred 63.83+/-16.35 vs. 79.11+/-14.15 vs. 87.01+/-10.5], a significantly higher respiratory disturbance index (RDI 46.34+/-26.90 vs. 31.79+/-22.47 vs. 4.98+/-3.29) a longer total sleep time with oxyhaemoglobin saturation<90% [total sleeptime (TST)SaO2<90% 63.40+/-33.86 vs. 25.95+/-29.34 vs. 8.22+/-22.12] and a lower rapid eye movement (REM) stage (9.5+/-1.2 vs. 14.0+/-0.9 vs. 17.05+/-1.2) than normocapnic subjects with obstructive sleep apnoea or subjects without obstructive sleep apnoea. The best model to predict PaCO2 resulted from a combination of TSTSaO2<90% (r2 = 0.22, P<0.001), forced expiratory volume in 1 sec (FEV1)% of pred (r2 = 0.09, P<0.01), FVC % of pred (r2 = 0.075, P<0.01). In conclusion our study suggests that diurnal hypercapnia is frequently associated with obstructive sleep apnoea in the morbidly obese without chronic obstructive pulmonary disorder (COPD) and that ventilatory restriction and sleep related respiratory disturbances correlate to diurnal hypercapnia.     

Breathing pattern and eye movement density during REM sleep in humans

Changes in the density of eye movement during rapid eye movement (REM) sleep are associated with changes in ventilation and ventilatory response in animals. Recent data in patients with chronic obstructive pulmonary disease suggest that periods of frequent eye movements may be associated with hypoxemia during REM sleep. We have therefore investigated the association between eye movements and ventilation and ventilatory pattern in 10 normal men. Expired ventilation was measured using a pneumotachograph attached to a valved face mask with a dead space of 50 ml and incorporating a peripheral CO2 leak detector. Ventilation was reduced (p less than 0.02) in all stages of sleep compared with that during wakefulness, with no difference between the level of ventilation in each sleep stage (awake, 7.18 +/- 0.43 SEM; Stage 2, 6.47 +/- 0.43; Stage 3/4, 6.45 +/- 0.52; REM sleep, 6.55 +/- 0.47 L/min). During REM sleep, eye movements (EMs) were associated with rapid shallow breathing. Dividing REM into 20-s epochs with or without EMs, EMs were associated with a raised breathing frequency (no EMs, 14.4 +/- 0.4 breaths/min; EMs, 15.8 +/- 0.5 breaths/min; p = 0.01), reduced tidal volume (0.49 +/- 0.03 L; 0.41 +/- 0.03 L; p less than 0.01), and reduced minute ventilation (6.87 +/- 0.45 L; 6.27 +/- 0.51 L; p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Androgen blockade does not affect sleep-disordered breathing or chemosensitivity in men with obstructive sleep apnea.

As sleep apnea is more prevalent in men and testosterone has known effects on sleep apnea and chemosensitivity, reduction of androgen activity may influence sleep-disordered breathing and respiratory control. We studied the effect of 1 wk of treatment with flutamide, a nonsteroidal antiandrogen, on sleep, respiration, and ventilatory control in eight men with sleep apnea. Results on flutamide were compared with two baseline studies performed before and after the drug treatment period. Although effective androgen blockade was achieved as evidenced by increased hormone levels, flutamide had no effect on sleep architecture or chemoresponsiveness to hypoxia and hypercapnia. There was a trend towards a reduction in respiratory disturbance index in both NREM and REM sleep (41 +/- 4 baseline versus 34 +/- 3 flutamide, p = 0.09 NREM; 53 +/- 4 baseline versus 48 +/- 3 flutamide, p = 0.16 REM), but this was not significant. Our results indicate that androgen blockade had no clinically significant effect on sleep, sleep-disordered breathing, or chemosensitivity in patients with moderate to severe sleep apnea. More specific blockers such as gonadotrophin-releasing hormone analogs may have more clinical effect or, alternatively, androgen blockade may be more beneficial in patients with milder sleep apnea.     

Low-flow oxygen and bilevel ventilatory support: effects on ventilation during sleep in cystic fibrosis

We measured ventilation in all sleep stages in patients with cystic fibrosis (CF) and moderate to severe lung disease, and compared the effects of low-flow oxygen (LFO2) and bilevel ventilatory support (BVS) on ventilation and gas exchange during sleep. Thirteen subjects, age 26 +/- 5.9 yr (mean +/- 1 SD), body mass index (BMI) 20 +/- 3 kg/m2, FEV1 32 +/- 11% predicted, underwent three sleep studies breathing, in random order, room air (RA), LFO2, and BVS +/- O2 with recording of oxyhemoglobin saturation (SpO2) (%) and transcutaneous carbon dioxide (TcCO2) (mm Hg). During RA and LFO2 studies, patients wore a nasal mask with a baseline continuous positive airway pressure (CPAP) of 4 to 5 cm H2O. Minute ventilation (V I) was measured using a pneumotachograph in the circuit and was not different between wake and non-rapid eye movement (NREM) sleep on any night. However, V I was reduced on the RA and LFO2 nights from awake to rapid eye movement (REM) (p < 0.01) and from NREM to REM (p < 0.01). On the BVS night there was no significant difference in V I between NREM and REM sleep. Both BVS and LFO2 improved nocturnal SpO2, especially during REM sleep (p < 0.05). The rise in TcCO2 seen with REM sleep with both RA and LFO2 was attenuated with BVS (p < 0.05). We conclude that BVS leads to improvements in alveolar ventilation during sleep in this patient group.     

The effects of oxygen in patients with sleep apnea

The effects of 6 h of continuous low flow, nasally administered oxygen were compared with the effects of breathing air in 10 men and 2 women with obstructive sleep apnea and daytime hypersomnolence. The overall quality of sleep, sleep fragmentation, the pattern of breathing, nocturnal oxygenation, and the clinical effects on daytime hypersomnolence determined by multiple sleep latency testing were evaluated. We found that in non-REM sleep, breathing 3 L/min of oxygen increased baseline percent arterial oxyhemoglobin saturation and decreased both the rate of sleep-disordered breathing from 69 +/- 36 to 56 +/- 39 (mean +/- SD) (p less than 0.02) episodes per hour and the peak fall in arterial oxyhemoglobin saturation from 11.5 +/- 5.6% to 6.5 +/- 4.0% (p less than 0.001). In addition, oxygen significantly reduced the percentage of central and mixed sleep-disordered breathing events, thus increasing the percentage of obstructive sleep-disordered breathing events. In contrast, during REM sleep, neither the baseline nor the peak fall in oxyhemoglobin saturation during disordered breathing improved; however, there was a significant reduction in hourly sleep-disordered breeathing rate from 70 +/- 17 to 56 +/- 23 (p less than 0.02) episodes. These improvements in oxygenation and pattern of breathing were associated with improved sleep architecture characterized by a decrease in the number of awakenings from sleep and an increased total sleep time from 335 +/- 72 to 369 +/- 68 min (p less than 0.05). Although 7 of 12 patients felt more alert after oxygen therapy, there was no overall improvement in multiple sleep latency test results.(ABSTRACT TRUNCATED AT 250 WORDS)     

Normal polysomnographic respiratory values in children and adolescents

STUDY OBJECTIVES: Polysomnography is important in the evaluation of children and adolescents with sleep-disordered breathing. Adult criteria for obstructive sleep apnea have been shown to be inapplicable to children. Nevertheless, very little data are available regarding normal respiratory parameters during sleep in healthy children and adolescents. The purpose of the study was to characterize normal polysomnography values in healthy children and adolescents and to establish respiratory reference values for pediatric polysomnography. DESIGN, SETTING AND PARTICIPANTS: Seventy healthy, normal children and adolescents were studied. Age ranged from 1 to 15 years (mean +/- SD, 8.02 +/- 4.57 years). All children underwent overnight polysomnography including EEG, electromyography, electrooculography, ECG, pulse oximetry arterial oxygen saturation (SpO(2)), chest wall and abdomen motion, oral and nasal airflow, and end-tidal PCO(2) (PETCO(2)). RESULTS: Three children (4%) had a mean of 0.37 obstructive apneas (OAs) per hour of sleep (1 to 5 OAs per child per study), with mean apnea duration of 10.3 +/- 2.1 s. This was not accompanied with oxygen desaturation. Twenty-six children had one to seven central apneas (CAs) per child, resulting in a mean of 0.4 CAs per hour of sleep (median, 0.33; 97.5 percentile, 0.9). Eleven of the 58 events of CA in six children coincided with oxygen desaturation to a minimum of 88% (nadir apnea desaturation range, 88 to 93%). The mean SpO(2) was 97.2 +/- 0.8% with SpO(2) nadir of 94.6 +/- 2.2%. PETCO(2) > 45 mm Hg occurred for 1.6 +/- 3.8% of total sleep time (TST) in 21 of 70 children (30%), with a distribution of 1.3 +/- 3.03% in the range of 46 to 47 mm Hg; < 0.7% were within the range of 48 to 50 mm Hg; and in 0.29 +/- 0.24% of TST, PETCO(2) values were > 50 mm Hg. CONCLUSIONS: Based on these data, the recommended limits for normal values are as follows: OA index, 1; CA index, 0.9; oxygen desaturation, 89%; baseline saturation, 92%; and PETCO(2) > 45 mm Hg for < 10% of TST.     

Expiratory flow limitation in awake sleep-disordered breathing subjects.

Increased upper airways (UA) collapsibility has been implicated in the pathogeny of sleep-disordered breathing (SDB). An increased UA instability during expiration has recently been shown in healthy subjects. The present study assessed UA collapsibility in SDB patients by applying negative pressure during expiration. Full-night polysomnography was performed in 16 subjects (all snorers) with a wide range of SDB, and in six healthy control subjects. Physical examination, spirometry, and maximal inspiratory and expiratory flow rates were within normal limits for all 22 subjects. Negative expiratory pressure (NEP) (-5 cmH2O) was applied during quiet breathing in seated and supine position. Flow limitation (FL) during NEP was expressed as the percentage of tidal volume during which expiratory flow was less than or equal to the flow recorded during quiet breathing (%FL). The mean desaturation index (DI) of the 16 subjects was 27.3+/-26.4 (+/-sD) and the average FL in supine position was 38.4+/-37.9%. A close correlation between %FL supine during wakefulness and DI during sleep (r=0.84, p<0.001) was found. All obstructive sleep apnoea subjects had >30%FL supine. There was no FL in the six control subjects. In conclusion, negative expiratory pressure application during expiration appears to be a useful, noninvasive method for the evaluation of subjects with sleep-disordered breathing. Present results suggest that upper airway collapsibility can be detected in these subjects during wakefulness.     

Hypoxemia during sleep in Duchenne muscular dystrophy

Overnight polysomnography after acclimatization was performed on 14 patients with Duchenne muscular dystrophy (mean age, 18.3 yr; mean VC, 1.24 L). Despite their lack of sleep-related symptoms and normal daytime blood gas tensions, periods of hypopnea and/or apnea (H/A) were observed in all patients (mean frequency 9.6/h; range, 3.7 to 17.0; mean duration 23.1; range of means, 16 to 36 s). In 9 patients, between 0.5 and 12.3 oxygen desaturations of greater than 5% occurred per hour, with falls from a mean SaO2 baseline of 95.4 +/- 0.6% (SEM) to a mean nadir of 74.2 +/- 3.9% (range, 58 to 90). This desaturating group (n = 9) showed longer and more frequent H/A than did the 5 nondesaturators; the proportion of REM sleep occupied by H/A was 37.7 +/- 3.8% in the desaturating group compared with only 15.1 +/- 5.1% in the remainder (p less than 0.01). The severity of sleep-disordered breathing could not be reliably predicted from daytime pulmonary function test results, and only maximal static expiratory pressure appeared significantly lower in the desaturating group. Hypopneas were associated with reduced chest wall movement in all subjects, and with chest wall paradox in one; continued submental "inspiratory" EMG activity throughout "central" apneas in 2 subjects suggested that these episodes were not truly central in origin. Sleep hypoxemia is imputed in the progression of several chronic respiratory diseases, and its prevention in Duchenne and related neuromuscular diseases may influence morbidity and mortality.     

Insomnia complaints in patients evaluated for obstructive sleep apnea

Obstructive sleep apnea (OSA) and insomnia are among the most common sleep diagnoses encountered in the sleep clinic population, however little is known about potential interactions or associations between the two disorders. This retrospective, cross-sectional study was designed to determine the prevalence of insomnia complaints in patients undergoing evaluation for OSA and to ascertain which clinical and polysomnographic features are associated with insomnia. Of 255 consecutive patients who underwent polysomnography for clinically suspected OSA, 54.9% reported a complaint of insomnia: 33.4% reported difficulty initiating sleep, 38.8% difficulty maintaining sleep, and 31.4% early morning awakenings. Insomnia complaints were noted more commonly in patients without significant sleep-disordered breathing [apnea hypopnea index (AHI)<10; 81.5%] vs those with sleep-disordered breathing (AHI≥10; 51.8%); p=0.01. Clinical factors associated with insomnia included female gender, psychiatric diagnoses, chronic pain, the absence of regular alcohol use, restless leg symptoms, and reports of nocturnal kicking. Polysomnographic factors associated with insomnia included lower AHI and lower desaturation index (DI). In the subgroup of patients with significant sleep-disordered breathing (AHI≥10, n=228), there was no association between insomnia complaints and AHI or DI. These results suggest that insomnia is a common complaint in patients being evaluated for OSA, but it is not strongly associated with sleep-disordered breathing and may instead reflect other coexisting factors.     

Effect of obesity and erect/supine posture on lateral cephalometry: relationship to sleep-disordered breathing.

Craniofacial and upper airway anatomy, obesity and posture may all play a role in compromising upper airway patency in patients with the sleep apnoea/hypopnoea syndrome. The aim of this study was to investigate the relationship between obesity, facial structure and severity of sleep-disordered breathing using lateral cephalometric measurements and to assess the effect of body posture on cephalometric measurements of upper airway calibre variables in obese and non-obese subjects. Lateral cephalometry was carried out in erect and supine postures in 73 awake male subjects randomly selected from patients referred for polysomnography who had a wide range of apnoea/hypopnoea frequencies (1-131 events x h sleep(-1)). Subjects were divided into non-obese (body mass index (BMI) < 30 kg x m(-2); n=42) and obese (BMI > or = 30 kg x m(-2); n=31) groups. Significant but weak correlations were found between apnoea/hypopnoea index (AHI) and measurements reflecting upper airway dimensions: uvular protrusion-posterior pharyngeal wall (r=-0.26, p<0.05) and hyoid-posterior pharyngeal wall (r=0.26, p<0.05). Multiple regression using both upper airway dimensions improved the correlation to AHI (r=0.34, p=0.01). Obese subjects had greater hyoid-posterior pharyngeal wall distances than non-obese subjects, both erect (42+/-5 versus 39+/-4 mm, respectively (mean+/-SD) p<0.01) and supine (43+/-5 versus 40+/-4 mm, p<0.05). Skeletal craniofacial structure was similar in obese and non-obese subjects. In conclusion, measurements reflecting upper airway size were correlated with the severity of sleep-disordered breathing. Differences in upper airway size measurements between obese and non-obese subjects were independent of bony craniofacial structure.     

Pulse transit time improves detection of sleep respiratory events and microarousals in children

OBJECTIVES: To evaluate the additional information provided by pulse transit time (PTT), a noninvasive tool, when using during polysomnography for the diagnosis of sleep breathing disorders in a pediatric population. MAIN FINDINGS: Respiratory and microarousals events were scored twice. The first scoring was performed using nasal pressure, thermistors, thoracic and abdominal movements, and oxygen saturation. The second scoring, blinded to the first scoring, was performed using PTT in combination with all the other signals. Microarousals were scored once visually on the EEG trace (cortical arousals [CAs]) and once using the PTT signal (autonomic arousals [AAs]) blinded to EEG. For the whole group of 16 children studied (mean age, 9.5 years), there was no significant difference between the respiratory disturbance index (RDI) with or without PTT analysis (22.4 +/- 13.5/h vs 20.4 +/- 14.3/h; not significant [mean +/- SD]). Among the children exhibiting a "without PTT" RDI < 30/h, 5 of 12 children (41.66%) showed a clinically significant >/= 5/h increase in RDI when using PTT. AAs detected by PTT were significantly more frequent than CAs during rapid eye movement (REM) sleep (7.4 +/- 3.9/h vs 3.2 +/- 2.3/h; p < 0.001) and slow wave sleep (SWS) [6.0 +/- 4.3/h vs 0.6 +/- 0.5/h; p < 0.0001]. CONCLUSIONS: The quantification of respiratory effort using PTT improves the detection of respiratory events in children. The detection of microarousals is improved particularly in REM and SWS.     

阻塞性睡眠呼吸暂停综合征的睡眠结构改变

目的研究阻塞性睡眠呼吸暂停综合征（ＯＳＡＳ）病情严重程度及持续气道内正压（ＣＰＡＰ）治疗对睡眠结构的影响。方法通过分析多导睡眠图，分析了３１例非ＯＳＡＳ者和１４７例ＯＳＡＳ患者的睡眠结构及ＣＰＡＰ治疗对１１例ＯＳＡＳ患者睡眠结构的影响。结果与对照组相比ＯＳＡＳ组的睡眠结构存在如下异常：（１）睡眠期转换次数（ＯＳＡＳ组：１２０±７１，对照组：９２±６０，Ｐ＝０．０１０６）、快波睡眠次数（ＯＳＡＳ组：８８±５４，对照组：６５±４５，Ｐ＝０．００７５）、醒觉次数（ＯＳＡＳ组：２７±２８，对照组：１９±１８，Ｐ＝０．０１７）差异有显著性；（２）慢波睡眠次数（ＯＳＡＳ组：５±９，对照组：８±８，Ｐ＝０．００３５）、占总睡眠时间的比例（ＯＳＡＳ组：５％±８％，对照组：８％±９％，Ｐ＝０．００６２）及慢波睡眠的缺乏率（ＯＳＡＳ组：４８％，对照组：２６％，Ｐ＜０．０５）亦明显不同；（３）睡眠呼吸紊乱指数低于２５的ＯＳＡＳ者与对照组比较睡眠各参数相差不大；（４）ＣＰＡＰ治疗能使上述参数得到不同程度的改善。结论ＯＳＡＳ主要引起睡眠的破碎、深睡减少及浅睡增加，且与病情的严重程度有一定关系。ＣＰＡＰ治疗能够改善这些紊乱。     

Reference values for nocturnal home pulse oximetry during sleep in primary school children

OBJECTIVE: To provide reference values for pulse oximeter saturation (SpO(2)) in primary school children, measured at home during sleep. METHODS: Recordings of SpO(2) and signal quality from 100 children were randomly selected from a larger population-based sample intended to study the prevalence of sleep-disordered breathing. Recordings were analyzed for the duration of artifact-free recording time (AFRT), minimum SpO(2) (SATmin) and median SpO(2) (SAT(50)), the SpO(2) below which the child spent 5% of AFRT (SAT(5)), and the SpO(2) below which the child spent 10% of AFRT (SAT(10)). In addition, the time in seconds with SpO(2) or= 4% per hour of AFRT (DI(4)), the number of falls in SpO(2) to 相似文献   

Effects of octreotide on sleep apnoea and tongue volume (magnetic resonance imaging) in patients with acromegaly

OBJECTIVES: Sleep apnoea has been consistently reported to occur in acromegaly. Both obstructive apnoeas, in which apnoeas are due to intermittent obstruction of the upper airways, as well as central apnoeas are known to occur. Because the relationship between disease activity and severity of sleep apnoea is currently unclear, we have performed a prospective study to address this issue. DESIGN AND METHODS: In 14 newly diagnosed patients with active acromegaly (eight females and six males; mean age 57+/-4 years; IGF-I 583+/-48 microg/l; GH 13.5+/-7.0 microg/l (means+/-s.e.m.)), tongue volume and signal intensity of the tongue were examined by magnetic resonance imaging and sleep apnoea was characterised by polysomnography before and after 6 months of treatment with octreotide acetate (Sandostatin LAR 10-30 mg every 4 weeks i.m.). RESULTS: The initial tongue volume was significantly higher in patients with acromegaly (151+/-9 ml; females 133+/-10 ml; males 172+/-10 ml) in comparison with the body mass index (BMI)- and age-matched healthy control group (97+/-5 ml, P<0.001; females 75+/-1 ml, P<0.001; males 120+/-3 ml, P<0.003). After treatment with octreotide, IGF-I was normalised within the age-adjusted normal range in 50% of the patients. In these patients, tongue volume significantly decreased (120+/-14 ml, P<0.05) in comparison with the persistent uncontrolled group of acromegalics (137+/-10 ml, P=not significant). Overall, tongue volume (128+/-8 ml, P<0.05) and the signal intensity ratio of the tongue decreased significantly after treatment with octreotide acetate (120+/-3 vs 105+/-3, P=0.003). The BMI-adjusted tongue volume correlated with IGF-I levels (r=0.60, P<0.002) and the disease duration (r=0.71, P=0.006). At baseline, 50% had obstructive sleep apnoea with a mean respiratory disturbance index (RDI) of >20/h (range 5.1-91.5) and no patient had central sleep apnoea. After 6 months of octreotide treatment, there was a 28+/-10% decrease in RDI. However, RDI did not correlate with IGF-I or GH levels, but correlated positively with BMI (r=0.58, P=0.001) and age (r=0.46, P=0.02). CONCLUSIONS: Obstructive sleep apnoea but not central sleep apnoea frequently occurs in patients with active acromegaly. Successful treatment with octreotide can decrease tongue volume, which may have benefits for coexisting sleep-disordered breathing.