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.     

Natural course of complex sleep apnea—a retrospective study

Patients with complex sleep apnea syndrome (CompSAS) have obstructive sleep apnea but develop troublesome central sleep apnea activity or Cheyne–Stokes breathing when provided continuous positive airway pressure (CPAP) therapy. We examined whether CompSAS activity persists with long-term CPAP treatment. We retrospectively identified all patients with CompSAS who underwent two therapeutic polysomnograms (PSGs) separated by at least 1 month during 2003–2005. We compared PSG findings between the initial and follow-up study and noted clinical responses to therapy. We identified 13 CompSAS patients meeting criteria. Most follow-up PSGs were ordered after an abnormal overnight oximetry on CPAP or because of CPAP intolerance after 195 (49–562) days. The residual apnea–hypopnea index (AHI) on CPAP decreased from 26 (23–40) on the first PSG to 7 (3–21.5) on the follow-up PSG. Only seven patients reached AHI < 10 and 6 had AHI ≥ 10 (“CPAP nonresponders”) at follow-up. “CPAP nonresponders” were sleepier (Epworth Sleepiness Score 13 [12.5–14] vs 9 [6–9.5], p = 0.03) and trended toward lower body mass index (29.7 [28.6–31.6] vs 34.3 [32.5–35.1], p = 0.06). Both groups were equally compliant with CPAP therapy. Although the AHI tends to improve over time in CompSAS patients treated with CPAP, in this retrospective study nearly half-maintained a persistently elevated AHI. A prospective trial is merited to determine the optimal treatment for these patients.     

CPAP adherence and partial upper airway obstruction during sleep

Nasal continuous positive airway pressure (CPAP) is the treatment of choice in severe obstructive sleep-disordered breathing (SDB). Partial obstruction is usually considered as mild SDB with poor CPAP adherence. In a retrospective study, we investigated the occurrence of partial obstruction in 233 age and BMI-matched male–female pairs and its impact on CPAP adherence after one year using static-charge-sensitive bed. Women had less SDB compared with men (21.8 vs 31.7% of time in bed (TIB), p < 0.001), less periodic breathing (5.8 vs 15.6%, p < 0.001) but tended to have more partial obstruction (10.5 vs 7.5%, p = 0.174). In women, partial obstruction accounted for 50.2% of breathing abnormalities, in men 37.2% (p < 0.001). CPAP adherence was 60.5% in women and 56.9% in men. When taking into account the proportion of partial obstruction (≤5 vs >5% of TIB) or periodic breathing, there were no differences in women’s CPAP adherence (p = 0.130 and p = 0.148, respectively). Men with periodic breathing over 5% of TIB tended to be more adherent to CPAP, (p = 0.052). The high occurrence of partial obstruction in both genders and particularly in women suggests that the apnea–hypopnea index underestimates the occurrence of SDB. There are no concerns of low adherence when treating symptomatic partial obstruction during sleep. Partial obstruction may not represent mild SDB but a different entity.     

Effect of continuous positive airway pressure ventilation on nocturnal ST-segment changes in patients with sleep-disordered breathing

Objective To determine whether sleep-disordered breathing (SDB) may lead to nocturnal myocardial ischemia and whether the severity of this ischemia may be relieved by nasal continuous positive airway pressure (CPAP). Methods Overnight polysomnogram examination and simultaneous 3-channel Holter monitoring were performed on 76 patients with moderate to severe SDB and no history of coronary heart disease. All the cases were treated with CPAP for one night. ST depression was defined as a ST segment decrease of more than 1 mm from baseline and lasting 1 min or more. The total duration (minutes) of ST depression was indexed to the total sleep time (minutes per hour of sleep). Results Twenty-eight patients (37%) showed ST segment depression during their sleep. Before CPAP treatment, the respiratory disturbance index (RDI) and arousal index were significantly higher during periods of ST depression than when ST segments were isoelectric, whereas no significant difference was found in blood oxygen saturation (SaO2). After the CPAP treatment of patients with ST depression, the duration of ST depression was significantly reduced from 36.8±18.9 to 11.4±13.2 min/h (P＜0.05). ST depression-related indexes, including RDI, arousal index and the percentage of sleep time spent at SaO2 below 90% (TS90/ TST), were all significantly decreased, with RDI from 63.4±23.8 to 8.1±6.6 /h, arousal index from 51.2±18.9 to 9.6±5.4 /h, and TS90/ TST from 50.6±21.4 to 12.9±14.7% (P＜0.05). Conclusion ST-segment depression is rather common in patients with moderate to severe SDB, and CPAP treatment can significantly reduce the duration of ST depression. ST depression in these patients may reflect the myocardial ischemia that really exists and the non-ischemic changes associated with recurrent SDB.     

Sleep-related breathing in children with mucopolysaccharidosis

Summary   Background: The mucopolysaccharidoses (MPSs), a group of genetic lysosomal storage disorders, are associated with significant morbidity. Secondarily to specific associated anatomical abnormalities, MPS is associated with sleep disordered breathing (SDB), specifically obstructive sleep apnoea (OSA) that may confer additional morbidity. Few studies have examined SDB in children with MPS using full polysomnography (PSG) and thus the exact prevalence and severity of SDB is unknown. Further, successful treatments for SDB in this population have not been explored. Objectives: This study evaluated both SDB and the efficacy of treatments offered to children with MPS using PSG data. Patients and methods: A retrospective chart review was conducted on all children with MPS and a history of suspected OSA who were referred to the Hospital for Sick Children, Toronto. Both baseline and follow up treatment PSG data were analysed. PSG data recorded included obstructive apnoea-hypopnoea index (OAHI) and central apnoea index (CAI). Results: Fourteen patients (10 male) underwent a baseline PSG. Three of 14 children on ERT were excluded from the main analyses. The median (range) baseline parameters of the population (n = 11) were recorded. The age was 5.2 years (0.8–17.8) and the body mass index (BMI) was 19.9 (13.7–22.2). The OAHI was 6.6 (0.0–54.8); the CAI was 0.6 (0.0–2.6). Seven of 11 (64%) had evidence for OSA and 3/7 children were classified as having severe OSA (OAHI > 10). Of these, 5/7 children underwent treatment for OSA with 3/5 children showing a significant reduction in their OAHI. Further, the 2 patients on ERT therapy with OSA were also both successfully treated. Conclusions: Children with MPS have a high prevalence of significant OSA and thus should be carefully screened for OSA using full polysomnography and treated accordingly. Competing interests: None declared     

Nasal pressure recordings to detect obstructive sleep apnea

Obstructive sleep apnea (OSA) is a common disease. Given the costs of in-laboratory polysomnography (PSG), alternative ambulatory methods for accurate diagnosis are desirable. The objective of this study was to evaluate the performance of a simple device (SleepCheck) to identify patients with sleep apnea. A total of 30 consecutive patients with suspected OSA syndrome referred to the sleep clinic were prospectively evaluated with standard PSG and SleepCheck simultaneously during an in-laboratory, supervised full-night diagnostic study. The PSG apnea and hypopnea index (AHI) was evaluated according to standard criteria, and SleepCheck assessed the respiratory disturbance index (RDI) based on nasal cannula pressure fluctuations. Compared to the full-night PSG, SleepCheck systematically overscored respiratory events (the mean difference between SleepCheck RDI and PSG AHI was 27.4±13.3 events per hour). This overscoring was in part related to normal physiologic decreases in flow during rapid eye movement sleep or after an arousal. However, there was reasonable correlation between AHI and RDI (r=0.805). Receiver operating characteristic curves with threshold values of AHI of 10 and 20/h demonstrated areas under the curves (AUCs) of 0.915 and 0.910, respectively. Optimum combinations of sensitivity and specificity for these thresholds were calculated as 86.4/75.0 and 88.9/81.0, respectively. Overall, the SleepCheck substantially overscored apneas and hypopneas in patients with suspected OSA. However, after correction of the bias, the SleepCheck had reasonable accuracy with an AUC, sensitivity, and specificity similar to other ambulatory type 4 devices currently available.This study was conducted at the Sleep Laboratory and Division of Orthodontics, The University of British Columbia, Canada     

Association of physical activity with sleep-disordered breathing

This study was performed to determine whether there is a protective association between participation in vigorous or vigorous/moderately vigorous physical activity and the prevalence of sleep-disordered breathing (SDB). Polysomnographic and questionnaire data from the baseline examination of 4,275 participants in the Sleep Heart Health Study (SHHS) were analyzed in relation to information on amount of physical activity and other potentially relevant factors collected from five SHHS parent cohorts (Atherosclerosis Risk in Communities Study, Cardiovascular Health Study, Framingham Heart Study, Strong Heart Study, and Tucson Epidemiologic Study of Airways Obstructive Diseases). Logistic regression models were fitted to determine if amount and strenuousness of physical activity was associated with the presence of SDB. At least 3 h per week of vigorous physical activity reduced the odds of SDB, defined as a respiratory disturbance index (RDI) of at least 15 apneas/hypopneas per hour (Adjusted OR, 0.68; 95%CI, 0.51–0.91). A qualitatively similar but slightly weaker association was observed when SDB was defined as a RDI ≥ 10 per hour (Adjusted OR, 0.81; 95%CI, 0.64–1.02). These findings remained after adjustment for sleepiness and restricting analyses to participants with good health. Three or more hours of moderately vigorous or vigorous physical activity also appeared to confer some protection against SDB, but these associations were weaker. Gender- and obesity-stratified analyses suggested that the protective association between physical activity and SDB occurred primarily in men and those who were obese. A program of regular vigorous physical activity of at least 3 h per week may be a useful adjunctive treatment modality for SDB, but this association needs confirmation with a prospective clinical trial.     

阻塞性睡眠呼吸暂停低通气综合征合并夜间多尿患者尿动力学改变情况分析

目的 观察存在夜间多尿的OSAHS患者的尿动力学变化.方法 前瞻性纳入武汉大学人民医院2002年9月至2008年6月存在夜间多尿、并经多导睡眠监测(PSG)诊断的OSAHS患者,共入选患者23例,其中男19例,女4例,年龄46～81岁,中位年龄68岁.记录患者夜晚及持续气道正压(CPAP)压力滴定夜晚的夜尿次数、夜尿量、夜尿渗透压和尿钠浓度,于研究当夜11时和次晨7时留取静脉血测定脑钠肽及心房利钠肽(ANP)水平.同时对每位患者进行尿动力学检查,包括尿流率,充盈期膀胱压,压力-流率及尿道压测定,并在使用CPAP治疗3个月后再次进行尿动力学检查.结果 PSG检查结果显示,本组患者均存在中重度OSAHS,平均睡眠呼吸暂停低通气指数(AHI)为(48±15)次/h.OSAHS患者夜间尿量明显增多,尿钠浓度增加,尿渗透压降低,次晨7时ANP水平升高,CPAP治疗3个月后可恢复正常.患者行CPAP压力滴定当夜排尿次数明显少于PSG监测当夜排尿次数.尿动力学检查显示本组患者尿动力学主要特征是逼尿肌收缩无力、膀胱感觉迟钝、低顺应性膀胱、逼尿肌尿道外括约肌协同失调.CPAP治疗后,逼尿肌收缩力增强,并恢复膀胱顺应性.结论 CPAP可有效减少OSAHS患者的夜间多尿症状,OSAHS患者夜尿量增多、尿渗透压下降及尿钠浓度增高症状可能与ANP升高有关,OSAHS病程可能损害膀胱逼尿肌功能.CPAP治疗可减少ANP分泌,同时改善膀胱逼尿肌收缩力.

Abstract：

Objective To investigate the urodynamic changes in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) and nocturnal polyuria. Methods From Sept. 2002 to Jun. 2008, 23 patients with nocturnal polyuria were diagnosed as having OSAHS by polysomnography(PSG). The number and output of nocturia, the osmotic pressure and the excretion of Na + were recorded during both the PSG night and CPAP titrating night. Plasma levels of brain natriuretic peptide (BNP) and atrial natriuretic peptides (ANP) were also measured at IIPM in the 2 nights and 7AM in the next mornings. Urodynamic studies including urine flow, bladder pressure during filling, pressure-flow study during voiding and urethral pressure were carried out in these patients. Urodynamic studies were performed again after treatment with CPAP for 3 months. Results PSG showed that the patients with nocturnal polyuria had moderate to severe OSAHS, in which the apnea-hypopnea index (AHI) being 48 ± 15 events per hour. The number of nocturnal voiding during the PSG night was more than that during the CPAP titrating night. During the PSG night, the output of nocturia, the nocturia excretion of Na+, ANP levels (at 7am in the next morning after PSG night)increased and the osmotic pressure of nocturia decreased. CPAP therapy could reverse these abnormalities.The main characteristics of urodynamics in these patients included weak detrusor contraction, hypoesthesia in filling cystometry, and decreased bladder compliance, and detrusor ex-ternal sphincter dyssynergia. After 3 months of CPAP treatment, both the myotility of the detrnsor of bladder and the bladder compliance improved. Conclusions CPAP therapy can effectively reverse the nocturnal polyuria in OSAHS patients. In OSAHS patients, the features of nocturia, including the changes of output, osmotic pressure and the excretion of Na+ , may be related to the secretion of high-level of ANP. During the course of chronic progressively OSAHS pathophysiology, detrusor function of bladder may be damaged. CPAP therapy could decrease the nocturnal excretion of ANP, and improve the myotility of the detrusor of bladder.     

Maintenance of wakefulness test in military personnel with upper airway resistance syndrome and mild to moderate obstructive sleep apnea

Background  Sleep-disordered breathing (SDB) and the associated symptom of excessive daytime sleepiness (EDS) in military personnel has influential consequences in both the garrison and the deployed environments. The maintenance of wakefulness test (MWT) is a daytime study used to evaluate the tendency to stay awake. We evaluated consecutive patients diagnosed with mild to moderate obstructive sleep apnea (OSA) and upper airway resistance syndrome (UARS) to provide an objective measure of their EDS using the MWT. Materials and methods  All military personnel referred between February 2004 and March 2005 with a clinical evaluation suspicious for SDB were evaluated with an overnight polysomnography (PSG). After overnight PSG, military personnel with mild to moderate OSA and UARS were evaluated with a 40-min protocol MWT. Abnormal MWT was defined as sleep onset latency mean below 19.4 min (<2 SD below the mean). Results  Sixty-two military personnel met entry criteria. Fifty-nine were men. Nineteen patients (32%) were diagnosed with UARS with a mean respiratory disturbance index of 11/h (5–20/h). Forty-one (68%) of the military personnel had OSA with a mean apnea–hypopnea index of 12/h (5–29/h). As a collective group, the mean Epworth Sleepiness Scale was elevated at 13/24 (1–24). This subjective excessive sleepiness was assessed with the MWT test, which resulted in a group mean MWT sleep onset latency of 27 min (5–40 min). Eighteen soldiers (30% of the total patients) had abnormal MWTs [six patients (33.3%) with UARS and 12 (67%) with OSA]. Conclusion  Military personnel with mild to moderate OSA and UARS often have abnormal MWTs and therefore have a pathological tendency to fall asleep. This EDS could pose a safety hazard in those personnel, military or civilian, who operate dangerous vehicles, machinery, or carry a firearm. Military personnel with untreated SDB are also at risk for the consequences of decreased mental alertness and decreased cognitive functioning due to daytime sleepiness. All work was completed at the Brooke Army Medical Center, Fort Sam Houston, Texas. The opinions expressed herein are those of the authors and should not be construed as official or reflecting the policy of either the Department of the Army, Department of Defense, or the US Government.     

Evaluation of a portable recording device (ApneaLink?) for case selection of obstructive sleep apnea

Objective  This study was designed to assess the sensitivity and specificity of a portable sleep apnea recording device (ApneaLink™) using standard polysomnography (PSG) as a reference and to evaluate the possibility of using the ApneaLink™ as a case selection technique for patients with suspected obstructive sleep apnea (OSA). Materials and methods  Fifty patients (mean age 48.7 ± 12.6 years, 32 males) were recruited during a 4-week period. A simultaneous recording of both the standard in-laboratory PSG and an ambulatory level 4 sleep monitor (ApneaLink™) was performed during an overnight study for each patient. PSG sleep and respiratory events were scored manually according to standard criteria. ApneaLink™ data were analyzed either with the automated computerized algorithm provided by the manufacturer following the American Academy of Sleep Medicine standards (default setting DFAL) or The University of British Columbia Hospital sleep laboratory standards (alternative setting, ATAL). The ApneaLink respiratory disturbance indices (RDI), PSG apnea–hypopnea indices (AHI), and PSG oxygen desaturation index (ODI) were compared. Results  The mean PSG-AHI was 30.0 ± 25.8 events per hour. The means of DFAL-RDI and ATAL-RDI were 23.8 ± 21.9 events per hour and 29.5 ± 22.2 events per hour, respectively. Intraclass correlation coefficients were 0.958 between PSG-AHI and DFAL-RDI and 0.966 between PSG-AHI and ATAL-RDI. Receiver operator characteristic curves were constructed using a variety of PSG-AHI cutoff values (5, 10, 15, 20, and 30 events per hour). Optimal combinations of sensitivity and specificity for the various cutoffs were 97.7/66.7, 95.0/90.0, 87.5/88.9, 88.0/88.0, and 88.2/93.9, respectively for the default setting. The ApneaLink™ demonstrated the best agreement with laboratory PSG data at cutoffs of AHI ≥ 10. There were no significant differences among PSG-AHI, DFAL-RDI, and ATAL-RDI when all subjects were considered as one group. ODI at 2%, 3%, and 4% desaturation levels showed significant differences (p < 0.05) compared with PSG-AHI, DFAL-RDI, and ATAL-RDI for the entire group. Conclusion  The ApneaLink™ is an ambulatory sleep monitor that can detect OSA and/or hypopnea with acceptable reliability. The screening and diagnostic capability needs to be verified by further evaluation and manual scoring of the ApneaLink™. It could be a better choice than traditional oximetry in terms of recording respiratory events, although severity may be under- or overestimated.     

自动持续正压系统对睡眠呼吸障碍的诊治

目的探索简便、临床易于推广应用的睡眠呼吸障碍疾患的诊治手段。方法对１１例睡眠呼吸障碍患者同步进行经典的多导睡眠图监测和自动持续正压系统监测，将监测结果进行比较；对２３例已确诊的阻塞性睡眠呼吸暂停综合征（ＯＳＡＳ）患者使用自动持续正压系统治疗，并对治疗效果进行评价。各监测指标比较采用ｔ检验。结果（１）自动持续正压系统与多导睡眠图相比较，自动持续正压系统虽无睡眠及心电记录，但可记录鼾声及上气道阻力；最高及最低血氧饱和度、最长呼吸暂停时间、呼吸暂停低通气（ＡＨＩ）指数等监测结果，两者相比，差异无显著性（Ｐ＞０．０５）；自动持续正压系统诊断ＯＳＡＳ的敏感性为７０％，特异性为１００％。（２）ＯＳＡＳ患者使用自动持续正压系统治疗后症状改善；ＡＨＩ显著减低，最低血氧饱和度显著升高（Ｐ＜０．００１）；此外，平均和最高压力与９５％可信压力比较差异有显著性。结论自动持续正压系统使用简便，并减轻了技术员监测时的劳动强度；在持续正压通气（ＣＰＡＰ）治疗时可采用９５％可信限所需的压力     

Influence of UPPP surgery on tolerance to subsequent continuous positive airway pressure in patients with OSAHS

To investigate the effect of uvlopalatopharyngoplasty (UPPP) on post-surgery continuous positive airway pressure (CPAP) treatment during sleep in patients with obstructive sleep apnea–hypopnea syndrome (OSAHS). Thirty-one OSAHS patients after UPPP surgery were recruited and studied on for more than 12 months after the procedure. Among them, 24 patients were treated with classical UPPP (cUPPP), which removes all of uvula and part of the soft palate. Seven had modified UPPP (mUPPP), keeping part of the uvula. The control group was 31 years in age, body mass index (BMI) and apnea–hypopnea index (AHI) matched, and newly diagnosed OSAHS patients without prior treatment. A manual titration of CPAP was performed during both (NREM) and non-rapid eye movement (NREM) sleep in all 62 patients. Patients were asked to keep a supine position while sleeping during the test. When significant mouth air leakage occurred and/or titration worsened with an increase of CPAP pressure, the pressure level was considered as the highest CPAP (hCPAP) a patient can tolerate in that sleep stage. The CPAP machine used for titration could produce highest pressure at 20 cm H₂O. There were 74% (23/31) of UPPP patients who had less than 50% decrease in AHI, and 84% (26/31) of the 31 patients still had AHI>15 (range 16–110) during post-operation polysomnography (PSG) test. Most of them need further CPAP therapy. All of the untreated OSAHS patients could tolerate 17–20 cm H₂O of CPAP during sleep. None had severe mouth air leak before an optimal pressure was reached. In contrast, four in the surgery group failed to respond to CPAP treatment during both NREM and REM sleep and one more during REM sleep. All of the seven patients who had a mUPPP could tolerate CPAP. One of the three tested both before and after surgery failed in the CPAP treatment after surgery during REM sleep. UPPP may compromise nasal CPAP therapy in OSAHS, especially in procedures with greater resection of the soft palate.     

Clinical associations between allergies and rapid eye movement sleep disturbances

Background

Allergic rhinitis, an immunoglobulin E inflammatory condition including nasal congestion, obstruction, sneezing, pruritus, and fatigue symptoms, has significant impact on quality of life and impairs sleep. Sleep‐disordered breathing (SDB) patients often have normal all‐night apnea‐hypopnea (AHI) or respiratory‐disturbance (RDI) indices on polysomnography (PSG). We hypothesized that the rapid eye motion–respiratory disturbance index (REM‐RDI) may be a novel predictor of allergic status.

Methods

A retrospective analysis of 100 patients compared REM‐RDI results in 67 allergen‐positive patients with 33 nonallergic patients who presented with nasal blockage. Subjects completed STOP‐Bang©, 22‐item Sino‐Nasal Outcome Test (SNOT‐22)©, and Epworth Sleepiness Scale© questionnaires and underwent skin‐prick testing (SPT) and PSGs including REM‐RDI values. Using multivariate logistic regression models, we evaluated relationships between allergic status and sleep parameters while controlling for possible confounders including body mass index (BMI).

Results

Using REM‐RDI as the outcome of interest, allergen‐positive patients were 3.92 times more likely to have REM‐RDI values in a moderate/severe range (≥15 events/hour); and patients with moderate/severe REM‐RDI values were more likely to be allergen positive (p < 0.05). Allergic status was not significantly related to all‐night AHI, RDI, or REM‐AHI. BMI was not significantly related to REM‐RDI. STOP‐Bang© was related to allergy status (p = 0.02) and REM‐RDI (p < 0.01). Allergic patients had increased REM latency and less total amount of REM.

Conclusion

We revealed significant bidirectional associations between allergen positivity and increased REM‐RDI values independent of BMI, AHI, RDI, and REM‐AHI. Allergic inflammation and REM‐RDI data may play important roles in diagnosing and treating fatigued SDB patients and as objective perioperative safety and outcomes measures.     

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.     

Automatic CPAP Performance in Patients with Sleep Apnea Plus COPD

Abstract

Background: Automatic CPAP devices have demonstrated good results in obtaining optimal fixed CPAP pressure to eliminate respiratory events in patients with sleep apnea-hypopnea syndrome (SAHS). However, automatic CPAP has not been fully studied in patients with COPD plus SAHS. Objectives: To analyse the performance of an automatic CPAP in severe COPD patients compared with SAHS patients with no associated co-morbidity. Methods: We compared 10 consecutive patients with SAHS and no associated co-morbidity and 10 patients with SAHS plus severe COPD who required CPAP titration. Automatic CPAP performance was studied during full-night PSG. Inadequate pressure increase periods, absence of pressure increases in reaction to respiratory events, air leak periods, and pressure behaviour in the face of erratic breathing periods were analysed. Results: The SAHS patients without co-morbidities vs. SAHS plus COPD patients presented: mean sleep efficiency, 80.2 (11.5)% vs. 76.5 (12.1)%; residual AHI, 6.3 (5.2) vs. 5.1 (7.7); residual CT90, 1 (3)% vs. 14 (1)%. The device´s performance demonstrates a mean of 1.2 (1.5) vs. 1.3 (1.2) periods of inadequate pressure increases; absence of pressure increases in reaction to respiratory events, 4.1 (5.4) vs. 0.6 (0.7) times; periods of air leaks, 1.3 (3.8) vs. 13.9 (11.7); mean optimal pressure, 9.1 (1.4) vs. 9.0 (1.9) cm H₂O. Conclusion: Titration with automatic CPAP could be as effective in patients with SAHS plus severe COPD as in patients with SAHS without COPD. However, the presence of more leakages must be taken into account.     

Prevalence of sleep-disordered breathing and continuous positive airway pressure compliance: results in chinese patients with first-ever ischemic stroke

OBJECTIVE: To assess the prevalence of sleep-disordered breathing (SDB), continuous positive airway pressure (CPAP) acceptance, and CPAP compliance in patients who have experienced ischemic stroke. DESIGN: A case-controlled study. SETTING: A university hospital. MEASUREMENTS AND RESULTS: We recruited 23 women and 28 men, who were admitted to the hospital within 4 days of stroke onset, with a mean (+/- SD) age of 64.2 +/- 13.0 years and a body mass index (BMI) of 24.3 +/- 4.4 kg/m(2) for this study. Twenty-seven patients (53%) and 9 patients (17.6%), respectively, reported a history of snoring and severe daytime sleepiness prior to experiencing a stroke, while the mean Epworth sleepiness scale score was 6.8 +/- 3.6. Polysomnography revealed 34 patients (67%) with an apnea-hypopnea index (AHI) of > or = 10 events per hour, 31 patients (61%) with an AHI of > or = 15 events per hour, and 25 patients (49%) with an AHI of > or = 20 events per hour. Significant obstructive SDB, defined as an AHI of > or = 20/h, was more prevalent in ischemic stroke patients than in control subjects (49% vs 24%, respectively; p = 0.04) and was associated with a higher BMI (p = 0.046). Among the 34 patients with an AHI of > or = 10/h, CPAP titration was tolerated by 16 patients, but only 4 patients who had typical sleep apnea features proceeded to home CPAP treatment with objective compliance over a period of 3 months of 2.5 +/- 0.6 h per night. A subgroup of 20 patients not receiving CPAP showed partial spontaneous improvement of SDB at 1 month (baseline AHI, 32.3 +/- 17.6 events per hour; AHI at 1 month, 23.0 +/- 18.8 events per hour; p = 0.01) with a trend toward improvement for the obstructive but no significant change for the central events, whereas no improvement in AHI was noted for the four patients receiving CPAP. CONCLUSION: There is a high prevalence of obstructive SDB in patients who have experienced acute ischemic stroke, which, in many cases, is different from classic obstructive sleep apnea syndrome, and this is reflected by the lack of significant sleepiness, poor CPAP acceptance, and partial spontaneous improvement at 1 month.     

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。     

Depression in sleep disorders clinics

Purpose  The purpose of this paper was to determine the incidence of depression in our sleep disorders clinics (and it’s relation to patient characteristics) and to determine whether the incidence of depression varies in patients with and without sleep apnea. Methods  The Beck Depression Inventory (BDI) was administered to evaluate patients for depression. We reviewed records of all new patients between November, 1995 and May, 1996 and determined their BDI scores and polysomnogram (PSC) results. Patients were divided based on their respiratory disturbance index (RDI); a cut off value of 15 was chosen. Patients were re-divided based on the BDI score (13 or greater suggestive of depression). The age, sex, body mass index (BMI), BDI or RDI (as appropriate) and arousal indices were compared. Results  Sixty-three patients were enrolled; 29% were depressed. BDI scores and PSG data were available in 42 patients. Those with a high RDI had significantly lower BDI scores and higher arousal indices. Those with a high and low BDI scores were not significantly different in any of the parameters evaluated. Conclusions  Symptoms of depression are commonly seen in a sleep clinic. In patients with symptoms suggestive of SA but with low RDI scores, a diagnosis of depression should be entertained. The presence of depression, however, should not negatively influence a decision to perform PSG. Presented in part at the 19th Annual Meeting of the Associated Professional Sleep Societies, Washington, D.C., May, 1996.     

Sleep apnea syndrome: improved detection of respiratory events and cortical arousals using oxymetry pulse wave amplitude during polysomnography

Respiratory events (RE) during sleep induce cortical arousals (A) and marked changes in autonomic markers in sleep apnea syndrome (SAS). The aims of the study were double. First, we assessed whether pulse wave amplitude (PWA) added to polysomnography (PSG) could improve RE and A detection; second, we wanted to know whether the quality of detection of these two parameters could be improved using PWA. Respiratory disturbance index (RDI) and A were randomly scored twice by the same observer in 12 male patients with SAS. The first scoring was done using conventional PSG signals, the second scoring adding PWA to PSG. We also measured interobserver agreement by randomly selecting and reading 100 PSG sequences of 5 min with and without PWA by two observers. Adding PWA to PSG parameters allowed to detect significantly more RDI (53.9 ± 21.6 h⁻¹ versus 48.3 ± 22.3 h⁻¹, p < 0.001) and more A (68.0 ± 14.4 versus 59.4 ± 16.5, p < 0.001). Moreover, after using PWA, there was no significant disagreement between two observers for detecting RE, showing better quality of RE detection. PWA is a simple and cheap parameter that improves the diagnostic value of conventional PSG in sleep apnea syndrome by better detecting respiratory events and A.     

CPAP compliance in patients with obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is characterized by repeated cessations of breathing during sleep. Major symptoms of this disease are excessive daytime sleepiness, snoring, and witnessed apnea. Most of the patients are treated with CPAP. In this study, we aimed to evaluate the factors affecting adherence to the CPAP treatment. Seventy-one patients were enrolled to this study. Patients were divided into three groups according to CPAP usage. Group I consisted of patients who had never used CPAP, group II consisted of patients who had used CPAP occasionally, and group-III patients had used CPAP treatment regularly. Group-III patients had higher apnea–hypopnea index (AHI) than groups I and II (respectively, 56.6 ± 27.7, 26.3 ± 7.5, and 32.3 ± 7.06; p < 0.000 for both). Oxygen desaturation index was significantly higher in group-III patients comparing to groups I and II (44.6 ± 22.3, 15.9 ± 8.3, and 25.6 ± 9.5; p < 0.000 for all). Our findings have shown that only very severe patients use the CPAP device regularly (mean AHI 56.6 ± 27.7). Compliance to CPAP treatment seemed to be poor in patients with moderate to severe, AHI about 30, OSAS. Considering the well-established benefits of CPAP treatment in patients with true indications, patients should be encouraged to use CPAP regularly, and complications of OSAS should be keynoted.