Increased upper airway collapsibility in children with obstructive sleep apnea during wakefulness

Upper airway collapsibility (UAC) is increased in children with sleep-disordered breathing (SDB), but during wakefulness, active neural processes preserve upper airway patency, such that measurement of upper airway dynamics using acoustic pharyngometry may contribute to diagnostic accuracy in snoring children. Upper airway cross-sectional area obtained from acoustic pharyngometry measurements was assessed in 247 children referred for evaluation of suspected SDB and control subjects, before and after application of cetacaine 1% spray to the pharyngeal introitus under visual inspection. UAC was determined from the precentage change in cross-sectional area after topical anesthesia. UAC measurements were reproducible 1 week apart in both control subjects and patients with SDB (p < 0.005). A UAC less than or equal to -30% exhibited high sensitivity and specificity in identification of all children with obstructive apnea-hypopnea index greater than 5/hour total sleep time in a prospective initial sample of 54 children and in a subsequent post hoc sample of 94 snoring children. Thus, upper airway dynamic testing during wakefulness in response to a topical airway anesthetic may provide a useful clinical adjunct to the evaluation of snoring children, with more accurate identification of those children with SDB.     

Daytime polysomnography for early diagnosis and treatment of patients with suspected sleep-disordered breathing

Excessive daytime sleepiness (EDS) is a common complaint among patients with sleep-disordered breathing (SDB). Population-based studies on traffic and industrial accidents suggest a relationship between EDS and life-threatening events, and adults with EDS have cognitive and memory problems. Nocturnal polysomnography (nPSG) is essential for diagnosing SDB but it is time and energy consuming. We examined the usefulness of daytime polysomnography (dPSG) for the early diagnosis and treatment of patients with suspected SDB. We studied 108 consecutive patients aged 51.9 +/- 13.5 years (mean+/-SD). All patients underwent dPSG and nPSG. The number of apnea/hypopnea episodes per hour (apnea/hypopnea index: AHI) and the number of 3% desaturation episodes per hour (desaturation index: DSI) were calculated. All patients were classified into two groups. The REM group consisted of subjects who had an AHI < or = 25/h, AHI(REM)/AHI(NREM) > 2, and AHI(NREM) < 15/h. Those who did not satisfy these criteria were placed in the NREM group. Continuous positive airway pressure (CPAP) titration was performed for patients whose AHI was > or =20/h on dPSG. Using the international classification of sleep disorders, 96 patients were diagnosed as obstructive sleep apnea [including five upper airway resistance syndrome (UARS) patients], six patients were snoring, four had idiopathic hypersomnia due to a medical condition, and two had circadian rhythm sleep disorders. The sensitivity of dPSG for AHI was 81.0%, specificity was 100%, and accuracy was 83.5%. The sensitivity and accuracy of dPSG for AHI in the REM group were considerably lower than in the NREM group. There was no significant difference for optimal CPAP between dPSG and nPSG. In the five patients with UARS, their AHI, DSI, and arousal index on dPSG were 0.92 +/- 1.2/h, 2.9 +/- 3.4/h, and 29.3 +/- 3.5/h, respectively, and their AHI and DSI on nPSG were 3.2 +/- 2.5/h and 2.8 +/- 2.4/h, respectively. However, their respiratory effort-related arousals were 37.9 +/- 7.4/h, and their arousal index was 33.2 +/- 6.3/h. The five patients with UARS were also treated with CPAP, and their daytime sleepiness was improved. Although dPSG has limitations, these results indicate that dPSG recording is clinically useful for the diagnosis of and determination of types of treatment in patients with suspected SDB.     

Continuous respiratory monitoring for sleep apnea screening by ambulatory hemodynamic monitor

AIM:To validate the sleep-disordered breathing components of a portable electrocardiography and hemodynamic monitor to be used for sleep apnea screening.METHODS:Sleep-disordered breathing(SDB) is associated with cardiovascular disease.Patients with existing cardiovascular disease may have unrecognized SDB or may develop SDB while under the care of a cardiologist.A screening device for SDB,easy to use and appealing to cardiologists,would assist in referral of appropriate patients for full polysomnography(PSG).A cardiac and respiratory monitor(CPAM) was attached to patients undergoing PSG and an apnea/hypopnea index(AHI) generated.The CPAM device produced respiration rate,snoring rate,individual apnea/hypopnea events and an SDB severity score(SDBSS).In addition to AHI,an expert over-reader annotated individual breaths,snores and SDB breathing events to which the automated algorithms were compared.RESULTS:The test set consisted of data from 85 patients(age:50.5 ± 12.4 years).Of these,57 had a positive PSG defined as AHI ≥ 5.0(mean:30.0 ± 29.8,negative group mean:1.5 ± 1.2).The sensitivity and specificity of the SDBSS compared to AHI was 57.9% and 89.3%,respectively.The correlation of snoring rate by CPAM compared to the expert overreader was r = 0.58(mean error:1.52 snores/min),while the automated respiration rate had a correlation of r = 0.90(mean error:0.70 breaths/min).CONCLUSION:This performance assessment shows that CPAM can be a useful portable monitor for screening and follow-up of subjects for SDB.     

Assessment of inspiratory flow limitation in children with sleep-disordered breathing by a nasal cannula pressure transducer system

A nasal cannula pressure transducer system identifies inspiratory flow limitation and increased upper airway resistance in adults with sleep-disordered breathing (SDB). The purpose of this study was to evaluate whether nasal cannula pressure (NCP) detects apneas and hypopneas as well as additional flow-limited events associated with increased airway resistance in children. We studied NCP in 47 patients (ages 2-14 years) referred for SDB to a university-based sleep disorders program during nocturnal polysomnography (NPSG). During NPSG, airflow was assessed simultaneously by thermistor and NCP. There was a high correlation between apneas assessed by thermistor (T) and NCP (r = 0.90, P < 0.0001), and for hypopneas using these two methods (r = 0.94, P = 0.0001). Respiratory driving pressure was indirectly measured with an esophageal pressure catheter. Flow-limited (flattened) NCP waves were associated with significantly higher driving pressure, indicating elevated upper airway resistance, compared to nonflow-limited (rounded) waves during nonrapid eye movement (NREM) (P = 0.05) and rapid eye movement (REM) (P = 0.01) sleep. Patients were classified as either having obstructive sleep apnea syndrome (OSAS) or primary snoring, based on standard NPSG criteria. NCP identified additional respiratory events with a flattened contour (FC) not detected by thermistor. NCP is a noninvasive device that identifies obstructive apneas and hypopneas as well as additional respiratory events associated with flow limitation in children.     

Detection of upper airway resistance syndrome using a nasal cannula/pressure transducer

STUDY OBJECTIVES: To determine the diagnostic utility of a nasal cannula/pressure transducer (NC), in comparison to thermistor (TH), during routine, clinical nocturnal polysomnography (NPSG). DESIGN: We analyzed the respiratory arousal index (RAI) using TH (RAI-TH) or NC (RAI-NC) in patients with suspected sleep-disordered breathing (SDB). SETTING: Sleep disorders center of a university-affiliated teaching hospital. PATIENTS: Fifty consecutive, nonselected patients referred for evaluation of suspected SDB. Measurements and results: Twenty patients were found to have obstructive sleep apnea/hypopnea syndrome (OSA), 25 had upper airway resistance syndrome (UARS), and 5 had primary snoring (PS). Mean RAI-NC was greater than the mean RAI-TH by 25%, 302%, and 500% in OSA, UARS, and PS, respectively. RAI-NC was >/= 14 (mean, 25.2) in UARS and < 14 (mean, 9) in PS. Mean RAI-TH was 8.4 in UARS and 1.8 in PS, with significant overlap between the two groups. CONCLUSIONS: NC is more sensitive than TH in detecting respiratory events during NPSG and may represent a simple, objective means to identify UARS among patients with a range of SDB.     

Reversibility of airflow obstruction by hypoglossus nerve stimulation in anesthetized rabbits

RATIONALE: Anesthesia-induced uncoupling of upper airway dilating and inspiratory pump muscles activation may cause inspiratory flow limitation, thereby mimicking obstructive sleep apnea/hypopnea. OBJECTIVES: Determine whether inspiratory flow limitation occurs in spontaneously breathing anesthetized rabbits and whether this can be reversed by direct hypoglossal nerve stimulation and by the application of continuous positive airway pressure. METHODS: Ten New Zealand White rabbits were anesthetized, instrumented, and studied supine while breathing spontaneously at ambient pressure or during the application of positive or negative airway pressure. Under each of these conditions, the effect of unilateral or bilateral hypoglossal nerve stimulation was investigated. MEASUREMENTS: Inspiratory flow and tidal volume were measured together with esophageal pressure and the electromyographic activity of diaphragm, alae nasi, and genioglossus muscles. MAIN RESULTS: Anesthesia caused a marked increase in inspiratory resistance, snoring, and in eight rabbits, inspiratory flow limitation. Hypoglossus nerve stimulation was as effective as continuous positive airway pressure in reversing inspiratory flow limitation and snoring. Its effectiveness increased progressively as airway opening pressure was lowered, reached a maximum at -5 cm H2O, but declined markedly at lower pressures. With negative airway opening pressure, airway collapse eventually occurred during inspiration that could be prevented by hypoglossus nerve stimulation. The recruitment characteristics of hypoglossus nerve fibers was steep, and significant upper airway dilating effects already obtained with stimulus intensities 36 to 60% of maximum. CONCLUSION: This study supports hypoglossus nerve stimulation as a treatment option for obstructive sleep apnea.     

Immunomodulatory effects of melatonin in asthma

We studied the changes in lung and upper airway mechanics in adult human subjects with obstructive sleep apnea/hypopnea syndrome (OSAHS) during wakefulness, sleep, and at arousal from sleep. We used two numerical methods that we have previously developed specifically for dealing with inspiratory flow limitation during sleep: the modified Mead-Whittenberger method, and information-weighted histograms obtained using recursive least squares. Full polysomnography including esophageal pressure and airflow measurements was performed in seven men with OSAHS (respiratory disturbance index: 55.8 +/- 23.2 events/h). Pharyngeal pressure was recorded in four of the subjects to partition lung mechanics into its upper airway and lower lung components. Both techniques showed that total lung resistance and elastance increased significantly (p < 0.05) during obstructed breathing and that this increase was reversed at the end of the obstruction. The partitioning of mechanics showed that upper airway collapse was primarily responsible for the increase in lung resistance. Our results suggest that OSAHS may lead to transient abnormalities in the recruitment of lung units and the gas exchanging capacity of the lungs.     

Performance of nasal prongs in sleep studies : spectrum of flow-related events

OBJECTIVES: The use of nasal prongs connected to a pressure transducer is a noninvasive, sensitive method to detect respiratory events, and can be easily implemented in routine sleep studies. Moreover, its good time response allows the detection of several flow-related phenomena of high interest, in addition to apnea and hypopnea. The aims of the study were to examine the quality and performance of the nasal prong flow signal, and to describe other flow-related events during full-night polysomnography studies. METHODS: Twenty-seven subjects were studied (16 male subjects; mean +/- SD age, 49 +/- 14 years; mean body mass index, 27 +/- 4 kg/m(2)): 15 subjects recruited from the general population and 12 consecutive patients with suspected sleep apnea/hypopnea syndrome (SAHS). RESULTS: A blind analysis of the respiratory events detected both by nasal prongs and thermistor was done. The quality of the nasal prong signal recordings was considered optimal for scoring purposes in 78% of cases, and no recording was considered uninterpretable. The nasal prong signal detected additional flow-related events not observed by the thermistor: (1) short and long (> 2 min) periods of inspiratory flow limitation morphology without decrease in the amplitude of the signal; (2) periods of mouth expiration; and (3) snoring. The apnea/hypopnea index was significantly higher with the nasal prong scoring (18 vs 11 [p < 0.05] in the general population and 37 vs 27 [p < 0.001] in the group with suspected SAHS). CONCLUSIONS: The incorporation of nasal prongs in routine full-night studies is an attainable technical option that provides adequate recordings in most cases. Additionally, relevant information not scored by thermistors is obtained on flow-related respiratory events, thus increasing diagnostic accuracy.     

New Technologies to Detect Static and Dynamic Upper Airway Obstruction During Sleep

Increase in upper airway resistance is the main patho-physiological feature in the obstructive breathing disorders during sleep. Upper airway events may be divided into two main groups: static obstruction (apneas) and dynamic obstruction (hypopneas, flow limitation, and snoring). This classification is useful to provide better information about the patho-physiological mechanisms of obstruction and to better define the diagnostic tools necessary for detecting abnormal respiratory events during sleep. Detection of dynamic obstruction requires sensors with a good frequency response. As thermistors have a poor dynamic response, they are not efficient in detecting the dynamic obstruction but are good enough to detect static obstruction. Nasal prongs (NP) connected a to pressure transducer and the impedance signal measured by the forced oscillation technique (FOT) are relatively new tools to noninvasively investigate dynamic upper airflow obstruction during sleep. FOT provides a direct index of the magnitude of airway obstruction and, therefore, of the upper airway patency, even under conditions of no flow (apneas). NP are aimed at assessing flow. Thus, both techniques have a different scope. The main advantages of NP are that they are easy to use and do not require sophisticated technology, while FOT needs a more complex instrumentation. For clinical routine studies NP are probably the best and simplest method for assessing the different respiratory events during sleep. However, FOT would be particularly useful in selected applications such as assessing upper airway patency in some central apneas; interpreting the irregular pattern of breathing during REM sleep; in better characterizing the inspiratory flow-limited breaths classified as intermediate; and in studying upper airway mechanics.     

Effect of air leak on the performance of auto-PAP devices: a bench study

Automatic positive airway pressure (auto-PAP) devices, used in the treatment of patients with obstructive sleep apnea (OSA), may not function optimally in the presence of an air leak. We set out to determine the magnitude of air leak that prevents auto-PAP devices from responding to respiratory events of OSA in a bench model. We simulated apnea, flow limitation, obstructive hypopnea, nonobstructive hypopnea, and snoring events of OSA with an artificial airway and a loudspeaker in a bench model connected to a commercially available auto-PAP device. Four auto-PAP devices were tested, but two of the “older-generation” devices (Tranquility and Virtuoso) did not respond to events of OSA that involved changes in flow contour; hence, we studied the effects of air leak and humidifier in the two “newer-generation” auto-PAP devices only (GoodKnight 418P, Autoset-T). When the air leak was progressively increased from baseline levels recommended by the manufacturer to levels seen clinically—5 to 7, 10, and 30 l/min—the GoodKnight 418P decreased pressure response by 56% (5.6±1.8 cm H₂O, p=0.04). The pressure response of the Autoset-T, however, did not change from baseline during similar levels of air leak. The GoodKnight performed appropriately when the air leak was within 20 l/min, but the corresponding value for the Autoset was higher at 50 l/min. For both devices combined, air leak caused the pressure to drop between the device and the airway: 2.8±0.3 cm H₂O at 30 l/min of air leak (p<0.001). Air leaks cause auto-PAP devices to underestimate the pressure required to treat events of OSA and to overestimate the pressure delivered at the upper airway. Physicians should be aware of performance limitations of auto-PAP devices in the presence of an air leak.     

阻塞性睡眠呼吸障碍患者频繁觉醒的原因探讨

目的探讨导致睡眠呼吸障碍患者睡眠中频繁发生觉醒的原因。方法对因有白天过度困倦而就诊的25例患者作全晚多导睡眠图(PSG)检查和呼吸模式分析,并与7名健康正常人对照。按国际标准人工判断觉醒。结果上气道阻力综合征(UARS)组10例,呼吸暂停／低呼吸指数(AHI)（2.5±1.4）次/h,动脉血氧饱和度(SaO2)<90%累计时间%(SLT90%)（0.1±0.1）%,觉醒指数(ArI)（30±16）次/h;阻塞性睡眠呼吸暂停综合征(OSAS)组15例,AHI（32.8±19.1）次/h,SLT90%（11.3±16.5）%,ArI（35±17）次/h;正常人组7名,AHI（5.9±4.4）次/h,SLT90%（0.2±0.4）%,ArI（13±5）次/h。OSAS和UARS组的ArI无统计学差异(H=0.49,P=0.48),均高于正常对照组的ArI(H分别为7.36和5.22,P值分别为0.001和0.02),但UARS组AHI、SLT90%明显低于OSAS组(H>5.00,P<0.05),与正常组相近(P>0.05)。结论睡眠时上气道吸气性阻力增高,是导致睡眠频繁觉醒的主要原因。     

Association of hypertension and sleep-disordered breathing

BACKGROUND: To our knowledge, the association between sleep-disordered breathing (SDB) and hypertension has not been evaluated in subjects from the general population with a wide age range while adjusting for the possible confounding factors of age, body mass index, sex, menopause and use of hormone replacement therapy, race, alcohol use, and smoking. METHODS: In the first phase of this study, we interviewed 4364 men and 12,219 women, aged 20 to 100 years. In the second phase of this study, 741 men and 1000 women, previously interviewed, were selected based on the presence of risk factors for SDB (snoring, daytime sleepiness, obesity, hypertension, and, for women, menopause). Each subject selected for the second phase of the study provided a comprehensive history, underwent a physical examination, and was evaluated for 1 night in the sleep laboratory. In terms of severity of SDB, 4 groups were identified: moderate or severe (obstructive apnea/hypopnea index > or =15.0), mild (snoring and an obstructive apnea/hypopnea index of 0.1-14.9), snoring, and no SDB, the control group. RESULTS: Sleep-disordered breathing was independently associated with hypertension when potential confounders were controlled for in the logistic regression analysis. The strength of this association decreased with age and was proportional to the severity of SDB. In the best-fitted model, neither sex nor menopause changed the relationship between hypertension and SDB. CONCLUSIONS: In the results of this study, SDB, even snoring, was independently associated with hypertension in both men and women. This relationship was strongest in young subjects, especially those of normal weight, a finding that is consistent with previous findings that SDB is more severe in young individuals.     

Anatomic determinants of sleep-disordered breathing across the spectrum of clinical and nonclinical male subjects

OBJECTIVES: We wished to determine the independent contribution of craniofacial dimensions of the upper airway to sleep-disordered breathing (SDB) in subjects who spanned the entire continuum of SDB. We also determined the interactive effects of body mass index (BMI) and age on the relationship between airway dimensions and SDB. DESIGN AND SUBJECTS: We studied 142 nonclinical male subjects in a working community population (average age, 47 years; average BMI, 29; average +/- SD apnea/hypopnea index [AHI], 20 +/- 20/h), and 62 patients with obstructive sleep apnea (average age, 47 years; average BMI, 32; average +/- SD AHI, 48 +/- 35/h. We determined the AHI from overnight polysomnography and the number of oxygen desaturations (> or = 2%) per hour of sleep. We used lateral facial cephalometric radiographs to measure 41 anatomic landmarks and 55 dimensions in the upper airway. SETTING: A university hospital and a sleep-disorders clinic. DATA ANALYSIS: We used stepwise regression analysis to determine the independent contributions of measured variables to SDB. MEASUREMENTS AND RESULTS: In the entire study population (n = 204), variations in BMI and six measures of craniofacial morphology accounted equally for one half of the total variance in AHI, and their interactive effects accounted for an additional 15%. Membership in the clinical or nonclinical group per se had no significant influence on these relationships. The single most important cephalometric variable in predicting AHI severity was the horizontal dimension of the maxilla (ie, porion vertical to supradentale [PV-A] distance). When the PV-A distance was relatively narrow (< 97 mm) the probability of having mild (AHI, 15 to 30/h) to severe (AHI > 30/h) SDB increased fivefold to sevenfold in nonobese subjects and threefold in obese subjects. Thus, in nonobese subjects (average BMI, 25 +/- 2) and in subjects with narrow upper airway dimensions, four cephalometric dimensions were the dominant predictors of AHI, accounting for 50% of the variance. However, in subjects with a large anteroposterior facial dimension, BMI was the major predictor of AHI and a BMI > 28 increased the probability of moderate-to-severe sleep apnea by approximately fivefold. Finally, the combination of cephalometric dimensions and BMI accounted for an increasing amount of the variance in AHI as the severity of AHI increased. CONCLUSIONS: Across the population spectrum of SDB, four cephalometric dimensions of the upper airway in combination with BMI accounted independently for up to two thirds of the variation in AHI; and the relative contribution of these two sets of determinants of AHI varied depending on airway size, obesity, and the amount of SDB.     

Gender differences in the expression of sleep-disordered breathing : role of upper airway dimensions.

STUDY OBJECTIVES: Obstructive sleep apnea (OSA) is a common disorder that is characterized by repetitive episodes of upper airway narrowing and collapse. Obesity is a major risk factor for OSA. Compared with men, women have greater total body fat and are more obese, and yet the prevalence of OSA is much higher in men. The airway size and compliance and pharyngeal muscle tone are important determinants of upper airway patency during sleep. The discrepancy between greater frequency of obesity and lower prevalence of OSA in women has not been explained and suggests a different pathogenetic mechanism underlying this condition. Most clinical studies in OSA have either combined the sexes or have described results from men only. The object of this study was twofold: (1) to examine the effect of obesity on pharyngeal size in both men and women, and (2) to determine the role of upper airway dimensions in the expression of sleep-disordered breathing (SDB) and its relationship to gender. DESIGN: Prospective study of subjects referred for evaluation of SDB. SETTING: University-based sleep center. SUBJECTS: Seventy-eight male patients (mean +/- SE age, 49.2 +/- 1.5 years) and 52 female patients (mean age, 47.4 +/- 1.5 years). MEASUREMENTS AND RESULTS: All subjects underwent in-laboratory polysomnography with measurement of upper airway size using the acoustic reflectance method. Although the two groups were similar in age, the female patients were slightly heavier than the male patients (body mass index [BMI], 36.0 +/- 1.7 kg/m(2) vs 33.3 +/- 0.8 kg/m(2), respectively; p < 0.0001). Despite similar clinical presentation of snoring and excessive daytime sleepiness, women had mild OSA (respiratory disturbance index [RDI], 9.2 +/- 2.7 events per hour) or increased upper airway resistance syndrome compared with men with more severe OSA (RDI, 28.0 +/- 3.5 events per hour; p < 0.0001). In contrast, women had a significantly smaller oropharyngeal junction and pharynx than men (p < 0.02). Upper airway size correlated significantly with the severity of sleep apnea in men only. There was no correlation between BMI and pharyngeal size in either gender. CONCLUSIONS: This study demonstrates that the static properties of upper airway in awake men but not women correlate with the severity of sleep apnea. This suggests inherent structural and functional differences in upper airway during sleep between men and women with more favorable airway mechanics in women.     

Polygraphy vs. polysomnography: missing osas in symptomatic snorers—a reminder for clinicians

Purposes

The purposes of this study are to investigate the usefulness of polygraphy (PG) in diagnosing obstructive sleep apnea (OSA) in sleepy/tired snorers compared to polysomnography (PSG) and, further, to search for suspected respiratory arousals in the PG.

Methods

One hundred eighty-seven adults suffering from sleepiness/tiredness and snoring had undergone ambulant PG and were considered to be normal, using American Academy of Sleep Medicine’s 2007 hypopnea criteria A. After approximately 7 months, in-lab PSG was performed using hypopnea criteria B, where arousals are also recognized. Validated questionnaires (Hospital Anxiety and Depression Scale, self-rated general health) were answered. In a subgroup, the sensitivity and specificity were calculated for flow limitation index (FLI) and flattening index (FlatI) in PG compared with the respiratory distress index (RDI) in PSG.

Results

Despite the normal PG, at PSG, the median RDI was 11.0 (range, 0–89.1). One hundred sixty-eight out of one hundred seventy-eight (90 %) were found to have at least mild OSA and 119/187 (64 %) with moderate–severe OSA according to the RDI values. The sensitivity and specificity were low (<70 %) for FLI and FlatI. Forty-nine percent of the patients rated anxiety at borderline or pathological levels, 35 % rated corresponding depression levels, and 45 % rated poor or fair general health.

Conclusions

PG was insufficient to rule out OSA when the respiratory events were mainly associated with arousals. Almost half of these patients experience low general health and psychiatric problems. We recommend a full-night PSG when PG is “normal”, and patients have symptoms of snoring and sleepiness/tiredness.     

Silent upper airway resistance syndrome: prevalence in a mixed military population

STUDY OBJECTIVES: The upper airway resistance syndrome (UARS) is a recently described form of sleep-disordered breathing in which transient increases in upper airway resistance result in repetitive EEG arousals. UARS is not associated with apnea or diminished airflow, although snoring and excessive daytime somnolence (EDS) are common. This report describes a subset of patients with UARS diagnosed by polysomnography who do not manifest snoring, which we define as silent upper airway resistance syndrome (SUARS). DESIGN: A retrospective review of all polysomnographies performed at our sleep disorders center during 2000. SETTING: Sleep disorders center of a large, academic, military hospital. PATIENTS: Our center serves military personnel, military retirees, and their dependent families. INTERVENTIONS: Esophageal manometry during polysomnography was routinely performed on patients with hypersomnolence (Epworth sleepiness scale > 10) who demonstrated a total arousal index >or= 10/h and a respiratory disturbance index of < 5/h on prior polysomnography. UARS was definitely diagnosed in patients who demonstrated repetitive increased upper airway resistance (IUAR) associated with brief EEG arousals followed by normalization of esophageal pressure (Pes). IUAR was defined by a pattern of crescendo negative inspiratory Pes of 相似文献   

Sleep-disordered breathing in patients with neuromuscular disease

Sleep-disordered breathing (SDB) is relatively common in general population as well as in patients with neuromuscular disease. SDB comprises a wide spectrum of disorders varying from simple snoring to complete closure of the upper airway as seen in obstructive sleep apnoea (OSA). It includes also other disorders like prolonged hypoxemia, hypoventilation, and central sleep apnoea (CSA). Neuromuscular diseases (NMD) form a group of disorders that can cause significant reduction in the quality and span of life. The involvement of respiratory system in the context of these disorders is the most serious complication, and it is considered as the leading cause of death in those patients. NMD can affect ventilation, cough, swallowing, and phonation. The involvement of respiratory muscles makes NMD patients vulnerable to sleep-disordered breathing with a significant prevalence of SDB among such patients.     

Sleep disordered breathing – a new component of syndrome x?

Sleep disordered breathing (SDB) is a complication of obesity estimated to occur in about 4–6% of overweight individuals. These respiratory disturbances during sleep incorporate a number of conditions including snoring, upper airway resistance syndrome and obstructive sleep apnoea syndrome (OSAS). It is thought that as well as having deleterious effects on sleep quality these conditions may also promote cardiovascular and hormonal changes leading to an elevated blood pressure and an increased incidence of cardiovascular morbidity. Evidence reviewed here points to an alteration in sympathovagal balance, baroreceptor sensitivity, insulin resistance and leptin, growth hormone and lipid levels. Whether these changes are a consequence of the associated obesity or the SDB itself remains to be proven.     

A community study of sleep-disordered breathing in middle-aged Chinese men in Hong Kong

BACKGROUND: Sleep-disordered breathing (SDB) in Asian populations is being increasingly recognized. This study investigated the prevalence of SDB in Chinese middle-aged office-based male workers in Hong Kong. METHODS: Sleep questionnaires were distributed to 1,542 men (age range, 30 to 60 years), and 784 questionnaires were returned. Subsequently, full polysomnographic (PSG) examinations were conducted in 153 questionnaire respondents. Subjects with an apnea-hypopnea index (AHI) > or =5 were recalled for clinical assessment. RESULTS: Questionnaire respondents were similar in age and body mass index (BMI) to the general community in the target age range and gender. Habitual snoring was reported by 23% of this cohort and was associated with excessive daytime sleepiness (EDS), hypertension, witnessed abnormal breathing pattern, BMI, and leg movements during sleep. Allowing for subject bias in undergoing PSG, the estimated prevalence of SDB and obstructive sleep apnea syndrome (OSAS) (defined as SDB in the presence of EDS) at various AHI cutoff threshold values was 8.8% and 4.1% (AHI > or =5), 6.3% and 3.2% (AHI > or =10), and 5.3% and 3.1% (AHI > or =15). Multiple stepwise logistic regression analysis identified BMI, habitual snoring, time taken to fall asleep, and age as predictors of SDB at AHI > or =5. Analysis of anthropometric parameters indicated that the relative risk of OSAS attributable to obesity was less than in white subjects. CONCLUSION: This community-based study of sleep apnea among middle-aged men in Hong Kong using full PSG demonstrated an estimated prevalence of OSAS (AHI > or =5 and EDS) at 4.1%. Increasing BMI and age were associated with SDB, although factors other than adiposity may also have an important pathogenic role in OSA in Chinese subjects.     

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.