The minimum period of polysomnography required to confirm a diagnosis of severe obstructive sleep apnoea

Background and objective: To combine the diagnosis of OSA with titration of positive airway pressure (PAP), current guidelines recommend that split‐night polysomnography (PSG) be performed if an AHI of ≥40/h is recorded over 2 h. However, the diagnostic validity of partial‐night PSG is uncertain. This study aimed to test the validity of partial‐night PSG and to determine the optimum AHI cut‐off points. Methods: Patients who visited the sleep centre at a tertiary medical centre between January and December 2008, for symptoms related to sleep disorders (sleepiness, snoring, sleep disturbance), and who completed full‐night PSG, were evaluated for this study. Full‐night PSG data were processed to obtain partial‐night PSG data, from which AHI were computed as a reference for diagnosing severe OSA. Full‐night and partial‐night PSG data obtained over different recording times (expressed as x‐h PSG, where x = 1–6) were compared using receiver operating characteristic (ROC) curve analysis. The diagnostic validity of 2‐h PSG with different AHI cut‐off points (25/h to 45/h) was also calculated. Results: Data from 198 PSG recordings was processed. For 2‐h PSG, an AHI cut‐off point of 30/h gave the highest accuracy of 90.9%. Comparing areas under the ROC curves (AUC), 2‐h PSG (AUC = 0.97) was as good as 2.5‐h PSG (AUC = 0.977, P = 0.057) and 3‐h PSG (AUC = 0.978, P = 0.125), but was better than 1.5‐h PSG (AUC = 0.955, P = 0.016). Conclusions: Partial‐night PSG is effective for diagnosing severe OSA. If there is an unabridged PSG recording indicating an AHI of ≥30/h for 2 h, severe OSA can be diagnosed and PAP titration initiated.     

Comparison of a simple obstructive sleep apnea screening device with standard in-laboratory polysomnography

Background

Obstructive sleep apnea (OSA) is a common underdiagnosed sleep disorder. Various strategies have been employed to easily screen for OSA. The ApneaStrip® (AS - S.L.P. Ltd, Tel Aviv, Israel) is an FDA approved OSA screening device applied to the upper lip at home. We evaluated the performance of this device against simultaneous in-laboratory polysomnography (PSG) in a group of well-characterized OSA patients.

Methods

Diagnostic PSG was performed in 56 patients (29 M, 37 F; age 48.9?±?14.6 years; body mass index [BMI] 37.5?±?9.0 kg/m²; apnea-hypopnea index—events/h—[AHI] 32.8?±?22.9). The AS was applied and positioned to detect nasal and oral airflow. The AS gives a “positive” result for AHI?≥?15. We examined the sensitivity and specificity of the AS against three thresholds derived from PSG: AHI?≥?5, AHI?≥?15 (company recommendation), and AHI?≥?30.

Results

For PSG AHI?≥?15, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the AS were 80, 54.5, 87.8, and 40 %, respectively. For PSG AHI?≥?5, the values were 75.1, 66.7, 97.1, and 13.3 %, respectively. For PSG AHI?≥?30, the values were 86.9, 36.2, 48.8, and 80 %, respectively. There were no significant modifying effects of age, BMI, gender, hypertension, diabetes, lung disease, and heart disease.

Conclusion

The AS has a high sensitivity for detection of OSA with AHI?≥?15, but only modest specificity. The AS could be a useful component of an OSA screening program; however, negative results should be interpreted cautiously.

     

Evaluation of a portable device for diagnosing the sleep apnoea/hypopnoea syndrome.

Waiting times for hospital-based monitoring of the obstructive sleep apnoea/hypopnoea syndrome (OSAHS) are rising. This study tested whether Embletta, a new portable device, may accurately diagnose OSAHS at home. A synchronous comparison to polysomnography was performed in 40 patients and a comparison of home Embletta studies with in-laboratory polysomnography was performed in 61 patients. In the synchronous study, the mean difference (polysomnography-Embletta) in apnoeas+hypopnoeas (A+H) x h(-1) in bed was 2 h(-1). In comparison to the apnoea/ hypopnoea index (AHI) x h(-1) slept, the Embletta (A+H) x h(-1) in bed differed by 8 x h(-1). These data were used to construct diagnostic categories in symptomatic patients from their Embletta results: "OSAHS" (> or = 20 (A+H) x h(-1) in bed), "possible OSAHS" (10-20 (A+H) x h(-1) in bed) or "not OSAHS" (<10 (A+H) x h(-1) in bed). In the home study, the mean difference in (A+H) x h(-1) in bed was 3 x h(-1). In comparison to the polysomnographic AHI x h(-1) slept, the Embletta (A+H) x h(-1) in bed differed by 6 +/- 14 x h(-1). Using the above classification, all nine patients categorised as not OSAHS had AHI < 15 x h(-1) slept on polysomnography and all 23 with OSAHS on Embletta had an AHI > or = 15 on polysomnography, but 18 patients fell into the possible OSAHS category potentially requiring further investigation and 11 home studies failed. Most patients were satisfactorily classified by home Embletta studies but 29 out of 61 required further investigation. The study suggested a 42% saving in diagnostic costs over polysomnography if this approach were adopted.     

自动持续气道正压系统诊断睡眠呼吸暂停综合征的临床评价

目的评价简易的自动持续气道正压系统（AutoSet）在临床上诊断睡眠呼吸暂停综合征（SAS）的应用价值。方法120例患者同时进行AutoSet和多导睡眠图（PSG）的监测研究,比较两种方法的呼吸暂停指数（AI）及呼吸暂停＋低通气指数（AHI）。结果两种方法的AI及AHI呈显著相关（r＝0．88,P＜0．001;r＝0．93,P＜0．001）。AutoSet上显示的呼吸紊乱指数（RII）与PSG的觉醒指数（Ai）呈显著相关（r＝0．72,P＜0．001）。如以AHI≥5、10、15、20次／小时为诊断标准,AntoSet诊断SAS的敏感性分别为94％、92％、91％、91％,特异性分别为80％、85％、92％、91％。结论AutoSet系统是一个诊断SAS敏感和有价值的工具,尤其对AHI≥30次／小时的SAS患者,其诊断价值更大,但对于轻、中度患者有一定的误差。     

Split-night versus full-night studies for sleep apnoea/hypopnoea syndrome.

Investigation and treatment of sleep apnoea/hypopnoea syndrome (SAHS) is placing increasing demands on healthcare resources. This workload may be reduced by using split-night studies instead of the standard full-nights of diagnostic polysomnography and continuous positive airway pressure (CPAP) titration. Split-night studies involve polysomnography in the first half of the night followed, if there is an abnormal frequency of apnoeas and hypopneas, by CPAP titration for the remainder of the night. The authors' database of all patients prescribed a CPAP trial 1991-1997 was used to compare long-term outcomes in all 49 (46 accepting CPAP) patients prescribed split-night studies with those in full-night patients, matched 1:2 using an apnoea/ hypopnoea index (AHI) of +/-15% and Epworth score of +/-3 units. Classical symptoms of SAHS were the main reason for the split-night studies (n=27). There were no differences between the groups in long-term CPAP use, median nightly CPAP use (split-night 6.0 h x night-1, interquartile range (IQR) 3.8-7.4, full-night; 6.2 h x night-1, IQR 3.7-7.0, p=0.9), post-treatment Epworth scores and frequency of nursing interventions/clinic visits required. The median time from referral to treatment was less for the split-night patients (13 months, IQR 11-20 months) than for full-night patients (22 months, IQR 12-34 months; p=0.003). Split-night studies, in selected patients, result in equivalent long-term continuous positive airway pressure use to full-night studies with shorter treatment times and less healthcare utilization.     

Watch-PAT睡眠监测系统与Compumedics多导睡眠监测系统的对比研究

目的 评价一种通过测定外周交感活性来判断呼吸事件的便携式睡眠仪Watch-PAT诊断阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的效率和准确度.方法 对20例疑诊OSAHS的患者在睡眠室由专业的技术人员同时进行多导睡眠仪(Compumedics)和Watch-PAT(型号:WP-200)监测.PSG的数据根据AASM指南由专业技术人员进行分析;Watch-PAT通过记录外周动脉弹性、心率、血氧饱和度和体位来判断呼吸暂停和低通气事件、血氧以及睡眠状态,并自动分析和生成报告.对比PSG和Watch-PAT的数据,比较的指标包括呼吸暂停低通气指数(AHI)、平均血氧饱和度(SpO2 mean)、最低血氧饱和度(SpO2min)、总睡眠时间(TST)和睡眠结构(REM/NREM).结果 受试者的年龄为(47.95±12.43)岁,体质量指数(BMI)为(28.82±4.15)kg/m2.PSG监测的AHI是(37.65±31.34)次/h.Watch-PAT和PSG的AHI、SpO2 min、SpO2 mean、TST和REM/NREM均高度相关(r=0.99,0.97,0.98,0.78,0.69,P值均＜0.001).Watch-PAT和PSG计算的AHI差异无统计学意义[(37.41±28.85)次/h比(37.65±31.34)次/h],P＞0.05).但Watch-PAT的TST和REM/NREM要高于PSG的结果(P ＜0.01);Watch-PAT的SpO2 mean和SpO2 min也高于PSG的结果(P＜0.01).当PSG AHI≥5次/h为诊断界值时,Watch-PAT AHI的ROC曲线下面积为1.0,其诊断的灵敏度和特异度分别是100％和100％(Watch-PAT AHI≥6.95次/h).当PSG AHI≥15次/h为诊断界值时,Watch-PAT AHI 的ROC曲线下面积为0.98,其诊断的灵敏度和特异度分别是100％和85.7％ (Watch-PAT AHI≥18.4次/h).通过Bland Altman图,可以看出PSG和Watch-PAT的诊断结果具有较好的符合度.结论 Watch-PAT通过测定外周动脉弹性来判断呼吸事件和睡眠状态的方法简单易行,结果可靠.是一种简便有效的便携式睡眠监测仪.     

Two months auto-adjusting versus conventional nCPAP for obstructive sleep apnoea syndrome.

Autoadjusting nasal continuous positive airway pressure (CPAP) greatly reduces the apnoea/hypopnoea index (AHI), and affords a significant reduction in median pressure (P50) compared-with manually titrated conventional nasal CPAP. The aim of the present study was to test whether these benefits were maintained in the medium term at home, in a double-blind crossover study. Ten sequential subjects (mean AHI 52.9 x h(-1)) were enrolled. After a manual titration, subjects were randomly allocated to 2 months autoadjusting nasal CPAP (AutoSet), followed by 2 months with the AutoSet device in fixed pressure mode at the manually titrated pressure, or vice versa. The machine-scored AHI, P50, and median leak were recorded on 12 nights in each arm, and averaged. Mean+/-SEM AHI was 4.0+/-0.3 x h(-1) in auto mode, and 3.7+/-0.3 x h(-1) in manual mode (NS). Mean+/-SEM P50 was 7.2+/-0.4 cmH2O auto, 9.4+/-0.6 cmH2O manual, average reduction 23+/-4% (p<0.0001). Auto "recommended" pressure was (mean+/-SEM) 10.1+/-0.5 cmH2O (p=0.04 with respect to manual) and peak pressure typically 1 cmH2O higher. Median (+/-SEM) leak was 0.181+/-0.006 L x s(-1) auto (and uncorrelated with AHI or pressure), 0.20+/-0.006 L x s(-1) manual (p=0.003). Compliance was 6.3+/-0.4 h in auto mode and 6.1+/-0.5 h in fixed mode (NS). Apnoea/hypopnoea index during 2 months of home autoadjusting nasal continuous positive airway pressure is comparable to that during conventionally titrated fixed pressure continuous positive airway pressure, while affording a 23% reduction in median pressure but no increase in compliance. Leak did not importantly affect autoadjustment.     

Home diagnosis of obstructive sleep apnoea in coronary patients: validity of a simplified device automated analysis

Introduction

Our aim was to evaluate a type 3 portable simplified device as a screening tool for obstructive sleep apnoea (OSA) in coronary patients.

Materials and methods

In 50 patients selected independently from sleep complaints, we compared the number of respiratory events per hour of valid recording time counted automatically by the device and the number counted manually per hour of sleep on polysomnography performed at home during the same night.

Results

Five patients were excluded because of technical failures. Estimated OSA prevalences (95% confidence interval) for apnoea/hypopnoea index (AHI) cut-offs ≥5, ≥15, and ≥30 by polysomnography were 0.93 (0.81–0.98), 0.69 (0.53–0.81), and 0.27 (0.15–0.42), respectively. The device would have correctly diagnosed 75% of patients with severe OSA (AHI ≥30 by polysomnography) and would have classified the remaining 25% as having moderate OSA.

Discussion

This ambulatory device may prove valuable in reducing the costs of diagnosing and managing OSA in coronary patients.     

Clinical diagnosis of sleep apnea based on single night of polysomnography vs. two nights of polysomnography

Purpose  The purpose of this study was to investigate apnea–hypopnea index (AHI) across two polysomnographies (PSGs) to examine AHI variability and impact on clinical diagnosis. Materials and methods  Two-night PSGs of 193 sleep clinic patients were reviewed, and the AHI variability was analyzed. Anonymized records from five patients with significant night-to-night AHI variability were used in this study: the two-night PSGs from two patients were represented as four individual PSGs; the two-night PSG for two others were represented as being obtained from two different sleep clinics; the last patient’s PSG was shown as a two-night study. Twenty-two sleep experts attending the Associated Professional Sleep Societies meeting were recruited to make diagnoses based on the PSGs. They were told that the PSGs were from seven patients: four with single-night PSG; two with two PSGs, each one from a different clinic; and one patient with a two-night PSG. Results  Twenty-one percent of the 193 sleep clinic patients had a nightly PSG AHI variability of greater than 5. Forty-eight percent of all patients had a significantly higher AHI on the first night, and 41% had a significantly higher AHI on the second night. Using an AHI > 15 diagnostic criteria, sleep apnea would have been undetected in 20% (n = 39) of patients due to low AHI on one night. Furthermore, 13% of all patients had a more severe sleep apnea classification based on the second night of PSG. For the seven cases, 27–36% of sleep experts failed to identify sleep apnea especially when presented with the PSG containing the lower AHI. Incidences of missed sleep apnea diagnoses were reduced to 15–18% when information from two PSGs was presented to the sleep experts. Conclusions  Utilizing a large patient population, this study supports the significant night-to-night variability in PSG respiratory variables. Identification of sleep apnea in some patients is reduced when sleep experts are provided with only one PSG recording. The clinical implication is that about 13% of sleep clinic patients might benefit from a second night of PSG. Disclosure statement: This study did not receive external funding.     

便携式睡眠监测与多导睡眠监测两种方法的应用比较

目的 比较便携式与多导两种睡眠监测仪在诊断睡眠呼吸暂停综合征（obstructive sleep apnea sydrom，OSAS）中作用的导同，为临床应用更简易、准确、低成本的诊断方法提供参考。方法 采用某进口的多导睡眠仪和便携式睡眠监测仪，对50例怀疑有OSAS的对象同时进行监测比较两种诊断方法各指标的差异，以及便携式监测仪的敏感性、特异性。结果 两种方法所得结果呼吸紊乱指数、氧减指数、平均血氧饱和度、最低血氧饱和度、低于90％的血氧饱和度时间等均无显著性差异（P＞O.05）。与多导睡眠监测仪比，便携式睡眠监测仪的敏感性为100％，特异性为60％；对病情分度判断的符合率分别为轻度73.3％、中度71.4％、重度94.4％。结论 便携式睡眠监测仪对诊断OSAS有高敏感性，尤其对重度OSAS的诊断更为准确，适合于临床常规诊断。具体应用时应注意选择有口鼻气流的传感。     

Resolution of central sleep apnoea following implantation of a left ventricular assist device

Central sleep apnoea (CSA) occurs in up to 40% of patients with chronic heart failure (CHF). It is thought to be a consequence of CHF and is associated with an accelerated decline in cardiac function, and increased morbidity and mortality. The optimal treatment of CSA remains unclear. Resolution of CSA has been reported after cardiac transplantation. We report the first case of resolution of CSA 10 months following implantation of a permanent Jarvik 2000 left ventricular assist device (LVAD). The correction of CSA after implantation of the LVAD was associated with improvements in symptoms, exercise capacity, renal function, and increased arterial carbon dioxide levels at rest during wakefulness and also reduction in brain natriuretic peptide.     

Diagnostic accuracy of level IV portable sleep monitors versus polysomnography for obstructive sleep apnea: a systematic review and meta-analysis

Purpose

Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder. In-laboratory, overnight type I polysomnography (PSG) is the current “gold standard” for diagnosing OSA. Home sleep apnea testing (HSAT) using portable monitors (PMs) is an alternative testing method offering better comfort and lower costs. We aimed to systematically review the evidence on diagnostic ability of type IV PMs compared to PSG in diagnosing OSA.

Methods

Participants: patients ≥16 years old with symptoms suggestive of OSA;intervention: type IV PMs (devices with <?2 respiratory channels); comparator: in-laboratory PSG; outcomes: diagnostic accuracy measures;studies: cross-sectional, prospective observational/experimental/quasi-experimental studies; information sources: MEDLINE and Cochrane Library from January 1, 2010 to May 10, 2016. All stages of review were conducted independently by two investigators.

Results

We screened 6054 abstracts and 117 full-text articles to select 24 full-text articles for final review. These 24 studies enrolled a total of 2068 patients with suspected OSA and evaluated 10 different PMs with one to six channels. Only seven (29%) studies tested PMs in the home setting. The mean difference (bias) between PSG-measured and PM-measured apnea-hypopnea index (AHI) ranged from ??14.8 to 10.6 events/h. At AHI ≥?5 events/h, the sensitivity of type IV PMs ranged from 67.5–100% and specificity ranged from 25 to 100%.

Conclusion

While current evidence is not very strong for the stand-alone use of level IV PMs in clinical practice, they can potentially widen access to diagnosis and treatment of OSA. Policy recommendations regarding HSAT use should also consider the health and broader social implications of false positive and false negative diagnoses.

     

Randomised short-term trial of high-span versus low-span APAP for treating sleep apnoea

Sleep and Breathing - Auto-titrating continuous positive airway pressure (APAP) devices were developed to improve treatment efficacy and compliance in patients with obstructive sleep apnoea...     

Investigations of an automatic screening device (MESAM) for obstructive sleep apnoea

A digital recording device developed to monitor heart rate (HR) and breathing sounds (snoring), and used to screen subjects for obstructive sleep apnoea syndrome (OSAS), was investigated. This device is called the MESAM and is currently commercially available in some western European countries. The computer-based automatic scoring systems provided with the equipment and a hand-scoring technique developed at Stanford and requiring 10-15 min to perform, were used. Polysomnography and MESAM recordings were performed simultaneously on two groups of 25 sleep disorder patients (each with respiratory disturbance index greater than or less than 10). Patients were randomly monitored and records were analysed by two teams blind to the initial clinical impression, to the events which occurred during the recordings, and to each other's findings. Specificity and sensitivity were calculated for each of the MESAM scoring techniques considered, with polysomnography being selected as the recording standard, With "automatic HR scoring" specificity was 12%, sensitivity 92%; with "automatic breathing sounds (snoring)" scoring, specificity was 8% and sensitivity 96%; with "hand-scoring" specificity was 72% and sensitivity 92%. If the three scoring techniques were combined, all patients with a respiratory disturbance index (RD) greater than 10 were recognized as having OSAS.     

Evaluation of a portable recording device (Somnocheck) for use in patients with suspected obstructive sleep apnoea.

BACKGROUND: Portable recording devices for the diagnosis of obstructive sleep apnoea (OSA) should be carefully evaluated before being used on a routine basis in out-patients. OBJECTIVE: This study was designed to evaluate the diagnostic accuracy of the new portable recording device, Somnocheck (SC). METHODS: Nocturnal polysomnographies (PSG) and SC recordings were performed simultaneously in the sleep laboratory in 51 patients with suspected OSA, and were analysed manually by a blinded investigator. RESULTS: The apnoea/hypopnoea index (AHI) obtained by manual SC analysis correlated closely with that obtained by PSG (r = 0.98), but the correlation with AHI obtained by automatic SC analysis was markedly lower (r = 0.83). When an AHI > or =10 was defined as indicative of OSA, the sensitivity of manual SC analysis was 0.97 and its specificity 1.00. The sensitivity of automatic analysis was 0.83 and its specificity 0.95. CONCLUSIONS: In this experimental setting, the SC showed a very high diagnostic accuracy for the diagnosis of OSA and was able to define its severity precisely. The diagnostic accuracy of manual analysis was found to be superior to that of automatic analysis. Considering the results of this technical evaluation, the SC may also be expected to work reliably when it is used in an ambulatory setting.     

Nasal obstruction as a risk factor for sleep apnoea syndrome.

Nasal obstruction has frequently been mentioned as a possible risk factor in obstructive sleep apnoea syndrome (OSAS). Over a 2-yr period, 541 unselected consecutive snorers referred for suspected breathing disorders during sleep were included to undergo posterior rhinomanometry. In addition cephalometric landmarks and body mass index (BMI) were obtained. Polysomnography was used to determine the number of abnormal respiratory events that occurred during sleep. OSAS was defined as 15 episodes, or more, of apnoea or hypopnoea per hour of sleep (AHI). Of the 541 consecutive snorers 528 underwent nasal resistance measurement by posterior rhinomanometry (failure rate: 2.4%). Patients with OSAS (259 patients) had higher nasal resistance than patients without OSAS (2.6+/-1.6 hPa x L x s(-1) versus 2.2+/-1.0 hPa x L x s(-1), respectively, p<0.005). A stepwise multiple regression analysis showed that BMI, male sex, nasal resistance, and cephalometric parameters were contributing factors to the AHI. The r2-value of the multiple regression analysis was 0.183. Nasal resistance contributed 2.3% of the variance (p<0.0001), whereas mandibular plane-hyoid distance, BMI, male sex and age contributed 6.2%, 4.6%, 3% and 1.3% of the variance, respectively. To conclude, daytime nasal obstruction is an independent risk factor for OSAS.     

Non-CPAP therapies in obstructive sleep apnoea: mandibular advancement device therapy

Mandibular advancement devices (MADs) represent the main non-continuous positive airway pressure (non-CPAP) therapy for patients with obstructive sleep apnoea (OSA). The aim of the European Respiratory Society Task Force was to review the evidence in favour of MAD therapy. Effects of tongue-retaining devices are not included in this report. Custom-made MADs reduce apnoea/hypopnoea index (AHI) and daytime sleepiness compared with placebo devices. CPAP more effectively diminishes AHI, while increasing data suggest fairly similar outcomes in relation to symptoms and cardiovascular health from these treatments. Patients often prefer MADs to CPAP. Milder cases and patients with a proven increase in upper airway size as a result of mandibular advancement are most likely to experience treatment success with MADs. A custom-made device titrated from an initial 50% of maximum mandibular advancement has been recommended. More research is needed to define the patients who will benefit from MAD treatment compared with CPAP, in terms of the effects on sleep-disordered breathing and on other diseases related to OSA. In conclusion, MADs are recommended for patients with mild to moderate OSA (Recommendation Level A) and for those who do not tolerate CPAP. The treatment must be followed up and the device adjusted or exchanged in relation to the outcome.