Predictors of sleep-disordered breathing in community-dwelling adults: the Sleep Heart Health Study

BACKGROUND: Sleep-disordered breathing (SDB) is common, but largely undiagnosed in the general population. Information on demographic patterns of SDB occurrence and its predictive factors in the general population is needed to target high-risk groups that may benefit from diagnosis. METHODS: The sample comprised 5615 community-dwelling men and women aged between 40 and 98 years who were enrolled in the Sleep Heart Health Study. Data were collected by questionnaire, clinical examinations, and in-home polysomnography. Sleep-disordered breathing status was based on the average number of apnea and hypopnea episodes per hour of sleep (apnea-hypopnea index [AHI]). We used multiple logistic regression modeling to estimate cross-sectional associations of selected participant characteristics with SDB defined by an AHI of 15 or greater. RESULTS: Male sex, age, body mass index, neck girth, snoring, and repeated breathing pause frequency were independent, significant correlates of an AHI of 15 or greater. People reporting habitual snoring, loud snoring, and frequent breathing pauses were 3 to 4 times more likely to have an AHI of 15 or greater vs an AHI less than 15, but there were weaker associations for other factors with an AHI of 15 or greater. The odds ratios (95% confidence interval) for an AHI of 15 or greater vs an AHI less than 15 were 1.6 and 1.5, respectively, for 1-SD increments in body mass index and neck girth. As age increased, the magnitude of associations for SDB and body habitus, snoring, and breathing pauses decreased. CONCLUSIONS: A significant proportion of occult SDB in the general population would be missed if screening or case finding were based solely on increased body habitus or male sex. Breathing pauses and obesity may be particularly insensitive for identifying SDB in older people. A better understanding of predictive factors for SDB, particularly in older adults, is needed.     

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.     

The utility of a portable sleep monitor to diagnose sleep-disordered breathing in a pediatric population

BACKGROUND:

Central and/or obstructive sleep-disordered breathing (SDB) in children represents a spectrum of abnormal breathing during sleep. SDB is diagnosed using the gold standard, overnight polysomnography (PSG). The limited availability and access to PSG prevents its widespread use, resulting in significant delays in diagnosis and treatment of SDB. As such, portable sleep monitors are urgently needed.

OBJECTIVE:

To evaluate the utility of a commercially available portable sleep study monitor (PSS-AL) (ApneaLink, ResMed, USA) to diagnose SDB in children.

METHODS:

Children referred to a pediatric sleep facility were simultaneously monitored using the PSS-AL monitor and overnight PSG. The apnea-hypopnea index (AHI) was calculated using the manual and autoscoring function of the PSS-AL, and PSG. Sensitivity and specificity were compared with the manually scored PSS-AL and PSG. Pearson correlations and Bland-Altman plots were constructed.

RESULTS:

Thirty-five children (13 female) completed the study. The median age was 11.0 years and the median body mass index z-score was 0.67 (range −2.3 to 3.8). SDB was diagnosed in 17 of 35 (49%) subjects using PSG. The AHI obtained by manually scored PSS-AL strongly correlated with the AHI obtained using PSG (r=0.89; P<0.001). Using the manually scored PSS-AL, a cut-off of AHI of >5 events/h had a sensitivity of 94% and a specificity of 61% to detect any SDB diagnosed by PSG.

CONCLUSIONS:

Although PSG is still recommended for the diagnosis of SDB, the ApneaLink sleep monitor has a role for triaging children referred for evaluation of SDB, but has limited ability to determine the nature of the SDB.     

Automated detection of sleep disordered breathing using a nasal pressure monitoring device

To assess the accuracy of a single channel portable monitoring device (RUSleeping™ RTS, Respironics, Murrysville, PA) that measures nasal pressure (a surrogate for airflow) to detect sleep disordered breathing (SDB). Twenty-five adult patients referred to a community sleep laboratory with suspected obstructive sleep apnea (OSA) participated in this investigation. The portable monitoring device was used in the sleep laboratory to acquire data concurrently with a standard multi-channel polysomnogram (PSG) to assess SDB. Respiratory events were scored manually on the PSG using standard criteria for clinical research to quantify an apnea–hypopnea index (AHI) based on events during sleep. The portable monitoring device automatically calculated an unedited respiratory event index (REI) based on recording time. These data were then compared using the Pearson product–moment correlation coefficient, Bland–Altman analysis, receiver operating characteristic (ROC) curves, and likelihood ratios. All 25 subjects completed the study. Mean age of subjects was 42.4 ± 12.9 years and mean body mass index was 31.0 ± 7.4 kg m⁻². There was good agreement between the REI and the AHI (R = 0.77, p < 0.001, mean difference 2.6 events per hour [2 SD: 39.8] using a Bland–Altman plot). The area under the ROC curve for detecting SDB (PSG AHI greater than or equal to five events per hour) with the REI was 0.94 (95% CI 0.84–1.0). For an REI >11.9 events per hour, the sensitivity was 0.89 (95% CI 0.65–0.99) and the specificity was 0.86 (95% CI 0.42–1.0) with a likelihood ratio of 6.2 for a positive test (LR+) and 0.13 for a negative test (LR−). Similar results were observed for detecting moderate–severe SDB (PSG AHI ≥ 15 events h⁻¹) using REI >15.2 events h⁻¹. In a population of subjects with suspected OSA, this portable monitoring device can automatically quantify an REI that compares well to the AHI scored manually on a concurrent PSG. Such a device may prove useful to assess SDB in high risk populations with self-administered testing in ambulatory settings such as the home. This study was performed at the Sleep Center of Greater Pittsburgh Sleep Laboratory.     

全电脑无纸记录多导睡眠图诊断睡眠呼吸暂停的评价

目的了解全电脑无纸记录多导睡眠图（ＮＷ）与经典的有纸记录多导睡眠图（ＰＳＧ）比较，其诊断睡眠呼吸暂停的可靠性及优越性。方法用ＮＷ与经典的ＰＳＧ对同一睡眠呼吸暂停综合征（ＳＡＳ）患者，在同一夜进行同步对照观察，共检测２０例患者，对其中１５例患者进行家庭监测。结果ＰＳＧ的呼吸紊乱指数（ＡＨＩ）为２８．６±６．９，ＮＷ测得的ＡＨＩ为２８．７±７．０；ＰＳＧ的最低血氧饱和度为７３．５％±２．８％，ＮＷ为７４．５％±３．２％。在ＡＨＩ≥５和≥１０两个诊断标准上的诊断一致率分别为９３．７％和９５．３％。结论全电脑多导睡眠图具有省时、省力、可携带等优点，是对经典的有纸记录的ＰＳＧ的一种补充，在绝大多数不需了解详细睡眠结构的患者，ＮＷ可以取代ＰＳＧ。     

Blood pressure associated with sleep-disordered breathing in a population sample of children

The current criteria for sleep-disordered breathing (SDB) in children are not based on a clinically relevant outcome. The purpose of this study was to assess the association of blood pressure with SDB in a random sample of the local elementary school children (kindergarten through grade 5) using a 2-phased strategy. During phase 1, a brief questionnaire was completed for all of the children (N=5740) with a response rate of 78.5%. During phase 2, 700 randomly selected children from phase 1 with a response rate of 70.0% were assessed with a full polysomnograph and a history/physical, including an ECG; ear, nose, and throat; and pulmonary evaluation. We observed a significantly elevated systolic blood pressure associated with the apnea hypopnea index (AHI): AHI >or=1 (2.9 mm Hg); AHI >or=3 (7.1 mm Hg); and AHI >or=5 (12.9 mm Hg). The SDB and blood pressure association remained significant after adjusting for age, sex, race, body mass index percentile or waist circumference, sleep efficiency, percentage of rapid eye movement sleep, and snoring. In addition, older age, body mass index percentile, waist circumference, and snoring were significantly associated with blood pressure, independent of SDB. Based on these findings, our study suggests that SDB is significantly associated with higher levels of systolic blood pressure in children aged 5 to 12 years even after adjusting for the various confounding factors. Clinically, the data support the threshold of AHI >or=5 for the initiation of treatment for SDB. Additional research is indicated to assess the efficacy of SDB treatment on reducing blood pressure.     

Age related differences in electroencephalographic and cardiac arousal at the termination of sleep apnea/hypopnea

OBJECTIVE: The purpose of the present study was to determine whether electroencephalographic (EEG) and cardiac arousal, i.e. heart rate elevation at the termination of apnea/hypopnea are related to aging. METHODS: The subjects were 13 middle-aged (40-60 years of age, 47.8+/-5.35 years) and 10 elderly (>60 years of age, 69.8+/-5.31 years) male patients with obstructive sleep apnea syndrome. We evaluated the number of apneas per an hour of sleep (apnea index: AI), the number of hypopneas per an hour of sleep (hypopnea index: HI), the summation of HI and AI (apnea/hypopnea index: AHI), sleep stage, the amount of time during which nocturnal oxygen saturation was decreased below 90% (oxygen desaturation time: ODT), and EEG and cardiac arousal at the termination of apnea/hypopnea using polysomnography with pulse oximetry. RESULTS: There was no significant difference in AHI, duration of apnea/hypopnea, and sleep stage distribution between the two groups. However, the ratio of apnea/hypopnea with EEG and cardiac arousal was significantly higher in middle-aged than in elderly patients. The ratio of HI to AHI was significantly lower in middle-aged than in elderly patients. In middle-aged patients, EEG and cardiac arousal were significantly correlated with AI, AHI, and ODT, whereas, in elderly patients, these parameters were not similarly correlated. CONCLUSION: Our findings suggest that the differences in EEG and cardiac arousal, and the pattern of sleep-disordered breathing (SDB) between middle-aged and elderly patients with SDB might be a physiological phenomenon of aging.     

The effect of correction of sleep-disordered breathing on BP in untreated hypertension

OBJECTIVES: To compare BP response to 3 weeks of nasal continuous positive airway pressure (CPAP) in hypertensive patients with and without sleep-disordered breathing (SDB). DESIGN: A controlled, interventional trial of nasal CPAP in patients with and without SDB. Participants and setting: Twenty-four men, aged 30 to 60 years, with mild to moderate untreated hypertension recruited from employee health and primary care clinics. METHODS: Based on in-laboratory polysomnography, 14 hypertensive patients had SDB, defined by five or more episodes of apnea and hypopnea per hour of sleep (apnea-hypopnea index [AHI], > or = 5), and 10 had no SDB (AHI, < 5). We performed 24-h ambulatory BP monitoring on all patients at baseline, during CPAP, and after CPAP treatment. In patients with an AHI > or = 5, nasal CPAP was titrated to reduce the AHI to < 5. Patients with an AHI < 5 received CPAP of 5 cm H(2)O to control for any potential effect of CPAP per se on BP. Both groups received CPAP for 3 weeks. RESULTS: After adjusting for age and body mass index, the mean nocturnal systolic and diastolic BP changes after CPAP treatment in the SDB group were significantly different from those in the no-SDB group: -7.8 vs +0.3 mm Hg (p = 0.02), and -5.3 vs -0.7 mm Hg (p = 0.03), respectively. There was a similar, although statistically insignificant, difference in the adjusted mean daytime systolic and diastolic BP changes after CPAP treatment between the two groups (-2.7 vs +0.4 mm Hg and -2.3 vs -1.7 mm Hg, respectively). CONCLUSIONS: Three weeks of nasal CPAP treatment of SDB in hypertensive men caused the lowering of nocturnal systolic and diastolic BP values, suggesting that increased nocturnal BP in persons with hypertension was causally related to the apnea and hypopnea events of SDB.     

Observations on the limitations of two apnea/respiration monitors commonly used in the home

The performance of two types of respiration monitor was studied with regard to detection of central apnea and individual breaths. Each monitor detected central apnea more frequently than routine intermittent nursing observation. Both false alarms, when the monitor failed to detect breathing movements (false positive for apnea), and false respiration signals, when the monitor failed to detect the absence of breathing movements (false negative for apnea) were found. The latter sometimes prevented alarms. It was found that a trial period of monitoring under the controlled conditions described permitted adjustments to be made which eliminated or minimized these sources of error. This should be considered when the monitors are issued for use in the home. It is important that persons issuing the monitors be aware of their limitations.     

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.     

Continuous positive airway pressure device-based automated detection of obstructive sleep apnea compared to standard laboratory polysomnography

Purpose

Obstructive sleep apnea (OSA) is a common health problem that affects more than 2–4% of the US population. Polysomnography (PSG) is the gold standard for diagnosing OSA. PSG is, however, expensive, time-consuming, and not always readily accessible. Hence, alternative diagnostic methods such as home-based testing have been evaluated. We studied the ability of the REMstar Pro (RSP2, a brand of continuous positive airway pressure (CPAP) device) to identify abnormal breathing events in subjects with OSA and compared this with breathing events simultaneously determined by laboratory-based PSG.

Methods

We evaluated 10 subjects previously diagnosed with OSA (apnea hypopnea index (AHI)?>?15, known therapeutic level of CPAP). Subjects underwent attended PSG using the REMstar Pro M series machine and their prescribed interface/mask type. The first 3 h of the study were conducted using a subtherapeutic CPAP (4 cm H2O). The last 3 h or remaining portion of the PSG was completed using the previously determined therapeutic CPAP. Comparison of respiratory events detected by PSG vs the RSP2 was performed.

Results

Subjects included four men and six women, aged 32 to 57 years and with a body mass index ranging from 29.5–66.4. The baseline AHI ranged from 18.3–93.1, with the AHI at therapeutic CPAP ranging from 0–3. Apnea counts at baseline and at therapeutic CPAP by manually scored PSG and REMstar were not significantly different (mean at subtherapeutic 11.7 vs 12.5, p?=?0.76; median at therapeutic CPAP 2.0 vs 4.5, p?=?0.15). Hypopnea counts at baseline and at effective CPAP by PSG and REMstar were not significantly different (mean at subtherapeutic 38.1 vs. 40.9, p?=?0.72; median at therapeutic CPAP 5.0 vs. 2.5, p?=?0.34). The correlation coefficient of REMstar and PSG for apnea and hypopnea was significant in subtherapeutic phase only (apnea r?=?0.78, p?=?0.007; hypopnea r?=?0.76, p?=?0.01). Agreement between the two methods declined for hypopnea detection at therapeutic CPAP.

Conclusions

The monitoring of residual sleep-disordered breathing on treatment, in addition to adherence, is an important objective therapeutic target in OSA. The REMstar Pro detects sleep-disordered breathing events similar to that of a manually scored PSG—for apnea but not for hypopnea—and merits further investigation as a device to determine disease severity and treatment efficacy.     

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.     

Incidence of sleep-disordered breathing in patients with hypertrophic cardiomyopathy

The authors investigated the prevalence of sleep-disordered breathing (SDB) together with its clinical correlations in patients with hypertrophic cardiomyopathy (HCM). A total of 113 consecutive patients including 63 patients with HCM (40 men; mean age, 59.5±13.0 years; New York Heart Association class, 2.0±0.9) underwent cardiorespiratory polygraphy in addition to their clinical work-up including echocardiography. Patients with an apnea-hypopnea-index (AHI) ≥5/h were considered to have SDB. If thoracic and abdominal inspiration efforts were documented, SDB was considered to be obstructive sleep apnea (OSA), otherwise SDB was considered to be central sleep apnea (CSA). The age- and sex-matched control group of 50 patients had exclusion of coronary artery disease by angiography, and normal left ventricular (ejection fraction ≥55%) and valvular function. SDB was diagnosed in 52 patients (82.5% vs 72% in the control group; P =not significant) with a mean AHI of 23.0±17.8/h. Severity of SDB was higher in patients with HCM than in the control group (AHI 12.2±7.6/h; P =.003). OSA was documented in 39 patients (AHI 21.2±16.5/h) and CSA in 13 (AHI 28.4±20.9/h). The severity of SDB correlated with New York Heart Association functional class (η=0.9, η(2) =0.811) and with left ventricular end-diastolic (r=0.6, P <.01) and left atrial (r=0.4, P <.01) diameter. No correlations were found between SDB and other clinical or echocardiographic parameters. SDB is common in patients with hypertrophic cardiomyopathy, with a predominance of OSA and correlations with markers of left ventricular function.     

Usefulness of arousals for the detection of sleep breathing disorder]

Because of the difference of sensitivity among measurement techniques, upper airway obstruction events cannot always be scored as apnea or hypopnea. We hypothesized that arousal accompanied with breathing disturbance is a more sensitive index for the diagnosis of sleep breathing disorders than others. We studied 75 patients with sleep breathing disorder by polysomnograph. Breathing disturbance related arousal (B-Ar) was defined as an arousal accompanied with at least one of the following (apnea, hypopnea, more than 4% oxygen desaturation, snoring), and the breathing disturbance indices were compared. There were close relationships between B-ArI and apnea hypopnea index (AHI), oxygen desaturation index (DI), and percent of total sleep time with SpO2 below 90% in all patients (r = 0.93, r = 0.58, r = 0.92, respectively, all p < 0.001). In 25 patients whose AHI was below 20 per hour, no relationship between B-ArI and AHI was found, and B-ArI was significantly greater than AHI. Thus, B-ArI seemed to be more sensitive than AHI. In all 6 patients whose AHI was below 10, B-ArI was lowered decreased by continuous nasal positive airway pressure therapy. These results suggest that B-ArI may be more sensitive in the detection of sleep breathing disorders than the other indices when AHI is below 20 per hour.     

智能动态血氧仪诊断睡眠呼吸暂停低通气综合征与多导睡眠图监测的一致性研究

目的：睡眠呼吸暂停低通气综合征(sleep apnea hypopnea syndrome,SAHS)是临床最常见的睡眠疾病之一,多导睡眠图监测为诊断的金标准。本研究将一种可无线传输数据至云平台并自动分析数据的腕表式智能动态脉搏血氧仪(简称“腕式血氧仪”)作为研究对象,与标准的多导睡眠图(polysomnography,PSG)监测做一致性分析,探讨腕式血氧仪对 SAHS诊断的可靠性。方法受试者为2015年6月至2016年2月就诊于首都医科大学附属北京朝阳医院呼吸科睡眠中心的疑似SAHS患者,所有受试者同时完成整夜 PSG监测和腕式血氧仪监测,分别比较 PSG和腕式血氧仪计算的氧减指数(oxygen desatuation index, ODI)、最低血氧饱和度(lowest percutaneous oxygen saturation,LSpO2)、<90%的血氧饱和度时间比率(the percentage of time spent at SpO2 below 90%, TS90%)和经皮平均血氧饱和度(mean percutaneous oxygen saturation,MSpO2)。并将 PSG 监测的呼吸暂停低通气指数(apnea hypopnea index,AHI)与腕式血氧仪监测的 ODI做一致性分析。用受试者工作特征(ROC)曲线评定 ODI诊断价值及判定诊断SAHS的界值。结果本研究共纳入201例受试者,PSG与腕式血氧仪监测的 ODI、TS90%、LSpO2之间差异无统计学意义;腕式血氧仪 ODI 与PSG监测的 AHI具有良好的相关性;ROC 曲线评价腕式脉搏血氧 ODI>10.4次/h 对 SAHS 的诊断价值敏感性及特异性均较高。结论 SAHS动态血氧波形有比较明显的特征,腕式血氧仪测得的 ODI可反应睡眠呼吸暂停的情况,可作为 SAHS的初筛设备。     

Automatic recognition of abnormal respiratory events during sleep by a pacemaker transthoracic impedance sensor

INTRODUCTION: A number of pacemakers use transthoracic impedance to derive minute ventilation as a sensor for rate adaptation. Transthoracic impedance is also able to track fluctuations in tidal volume occurring in sleep apnea/hypopnea syndromes (SAS). We evaluated the feasibility of a transthoracic impedance-derived pacemaker algorithm for monitoring sleep respiratory disturbances. METHODS AND RESULTS: Forty-two patients who presented with a conventional indication for DDD pacing or cardiac resynchronization underwent conventional polysomnography 1 month after implantation of a Talent trade mark 3 pacemaker (ELA Medical). The respiratory disturbance index (RDI) stored in the pacemaker memory was compared to the apnea/hypopnea index (AHI) derived from polysomnography. The ability of the pacemaker to identify severe SAS patients (AHI > or = 30) was assessed. A minimal systematic error was observed from a Bland and Altman plot (bias = 0.9 events/hour). The ability of the pacemaker RDI to identify severe SAS patients was determined by analysis of the receiver operator characteristic. A cutoff RDI value of 30.6/hour of recording was found to yield 75% sensitivity, 94% specificity, 75% positive predictive value, and 94% negative predictive value. CONCLUSION: The RDI monitoring function appears to be of value in screening pacemaker patients for SAS. Its performance is comparable to existing simple screening techniques. The ability to permanently monitor respiration, in combination with other diagnostic capabilities (such as Holter functions), presents a unique opportunity to monitor the association between arrhythmias and disturbances of breathing during sleep.     

Sleep-disordered breathing in healthy aged persons: possible daytime sequelae

We assessed the overnight sleep and breathing as well as daytime medical, sleep, and psychological status of a group of 34 healthy older persons. Analyses indicated that sleep-disordered breathing (SDB) was not related to any aspects of daytime functioning as measured in this study and that persons with an apnea + hypopnea index (AHI) greater than or equal to 5 (M AHI = 14.6) were not significantly impaired relative to those with lower levels of SDB (M AHI = 1.0) on any aspect of daytime performance. We conclude that SDB occurring in healthy aged persons is probably not of immediate concern and that the use of a cutting score of AHI greater than or equal to 5 for diagnosis of sleep apnea syndrome is not indicative in healthy aged persons. However, these results may not be applicable to older persons who are not in the excellent state of health that was required for participants in our study.     

Reliability and accuracy of sleep apnea scans in novel cardiac resynchronization therapy devices: an independent report of two cases

Pacemaker apnea scan algorithms are able to screen for sleep apnea. We investigated whether these systems were able to accurately detect sleep-disordered breathing (SDB) in two patients from an outpatient clinic. The first patient suffered from ischemic heart failure and severe central sleep apnea (CSA) and underwent adaptive servoventilation therapy (ASV). The second patient suffered from dilated cardiomyopathy and moderate obstructive sleep apnea (OSA). Pacemaker read-outs did not match polysomnography (PSG) recordings well and overestimated the apnea–hypopnea index. However, ASV therapy-induced SDB improvements were adequately recognized by the apnea scan of the Boston Scientific INVIVE® cardiac resynchronization therapy pacemaker. Detection of obstructive respiratory events using impedance-based technology may underestimate the number of events, as frustrane breathing efforts induce impedance changes without significant airflow. By contrast, in the second case, apnea scan overestimated the number of total events and of obstructive events, perhaps owing to a very sensitive but less specific hypopnea definition and detection within the diagnostic algorithm of the device. These two cases show that a pacemaker apnea scan is able to reflect SDB, but PSG precision is not met by far. The device scan revealed the decline of SDB through ASV therapy for CSA in one patient, but not for OSA in the second case. To achieve reliable monitoring of SDB, further technical developments and clinical studies are necessary.     

应用动态心电图推导呼吸曲线人工分析的方法初筛睡眠呼吸暂停低通气综合征

目的:以多导睡眠分析仪作对照,探讨应用动态心电图推导呼吸曲线(EDR),采用人工分析的方法初筛睡眠呼吸暂停低通气综合征(SAHS)的可行性。方法:2004年4月～2005年10月对120例就诊于睡眠中心的患者进行整夜(>7h)多导睡眠分析仪监测,同时同步进行动态心电图检查。双方在互相不沟通的情况下分别计算睡眠呼吸暂停低通气指数(AHI),并做出SAHS阳性与阴性的诊断,以多导睡眠分析仪结果作为金标准评价应用EDR技术初筛SAHS的可行性。结果:120例患者通过多导睡眠分析仪监测,结果88例患者SAHS阳性,32例患者SAHS阴性,应用动态心电图EDR技术人工分析方法初筛SAHS结果敏感性85.2%、特异性93.8%、阳性预测值97.4%、阴性预测值69.8%、诊断符合率87.5%。受试者工作特性曲线(ROC)下面积0.938,经相关分析两者AHI的相关系数为0.879(P=0.000),两者最长睡眠呼吸暂停时间的相关系数为0.716(P=0.000),两者最长睡眠低通气时间的相关系数为0.281(P=0.005)。结论:应用动态心电图EDR技术,采用人工分析方法对可疑SAHS患者进行初筛的符合率较高,可以作为临床上SAHS诊断的辅助工具。