Intra-night variation in apnea-hypopnea index affects diagnostics and prognostics of obstructive sleep apnea

Sleep and Breathing - Diagnostics of obstructive sleep apnea (OSA) is based on apnea-hypopnea index (AHI) determined as full-night average of occurred events. We investigate our hypothesis that...     

Prediction of the apnea-hypopnea index from overnight pulse oximetry

STUDY OBJECTIVE:s: To compare the relative usefulness of the different indexes derived from pulse oximetry in the diagnosis of obstructive sleep apnea (OSA), and to determine if a combination of these indexes improves the prediction of the apnea-hypopnea index (AHI) measured by polysomnography. DESIGN: Prediction model developed from 224 patients, validated prospectively in 101 patients from the same center (group 1) and in 191 patients from a different sleep center (group 2). SETTING: Two independent sleep clinics run by university sleep specialists. PARTICIPANTS: Patients who underwent polysomnography for suspicion of OSA. INTERVENTIONS: The following indexes were calculated from pulse oximetry recordings performed simultaneously during polysomnography: (1) Delta index, the average of the absolute differences of oxygen saturation between successive 12-s intervals; (2) desaturation events per hour to 2%, 3%, and 4% levels; and (3) cumulative time spent below 90%, 88%, 86%, 84%, 82%, and 80% saturation. MEASUREMENTS AND RESULTS: The best predictor was the Delta index, although desaturation events provided similar levels of diagnostic accuracy. An aggregation of multivariate models using combination of indexes reduced the prediction error (r(2) = 0.70) significantly (p < 0.05) compared to using the Delta index alone (r(2) = 0.60). The proportion of subjects from the validation groups within 95% confidence interval (CI) of the derivation group was 90% (95% CI, 83 to 95%) and 91% (95% CI, 86 to 95%) for groups 1 and 2, respectively. The overall likelihood ratios for the aggregated model in all patient groups were 4.2 (95% CI, 3.3 to 15.3), 3.4 (95% CI, 2.7 to 4.3), 3.0 (95% CI, 2.2 to 4.1), and 6.7 (95% CI, 4.9 to 9.2) for normal (AHI < 5/h), mild (AHI 5 to < 15/h), moderate (AHI 15 to < 30/h), and severe (AHI > or = 30/h) disease, respectively. CONCLUSIONS: The Delta index and oxygen desaturation indexes provided similar levels of diagnostic accuracy. The combination of indexes improved the precision of the predicted AHI and may offer a potentially simpler alternative to polysomnography.     

Breath-to-breath variability correlates with apnea-hypopnea index in obstructive sleep apnea

BACKGROUND: Breathing in patients with obstructive sleep apnea (OSA) is frequently interrupted by periods of hypopnea and apnea. There is limited information regarding a possible disturbance of breathing outside these periods. STUDY OBJECTIVE: To analyze the degree of breathing disturbance during nonocclusion. DESIGN: Prospective determination of breathing variability during full polysomnographic sleep studies. PATIENTS: Breath-to-breath variation was monitored in 34 patients with OSA and in 9 healthy subjects. MEASUREMENTS AND RESULTS: All breath-to-breath intervals were automatically analyzed from flow signal, displayed, and manually corrected for artifacts. Distribution of all nonapneic breath intervals was analyzed for the extent of difference from a normal distribution pattern by specifying kurtosis. In untreated OSA patients, kurtosis was significantly reduced (0.0 +/- 0.5, mean +/- SD) compared to control subjects (0.8 +/- 0.5), indicating increased variability of nonoccluded breathing. This effect was present in all sleep stages, and the extent depended significantly on the degree of disease. Continuous positive airway pressure breathing was able to normalize kurtosis (1.0 +/- 0.9) immediately. CONCLUSIONS: Breathing in OSA is not only characterized by interruptions of breathing during occlusion, but by a greater variation in the pattern of normal-length breaths.     

Impact of different criteria for defining hypopneas in the apnea-hypopnea index

OBJECTIVES: To explore the effect of using different scoring criteria for hypopneas in the scoring of polysomnographic studies: (1) by estimating the level of agreement between apnea-hypopnea index (AHI) scores derived from different scoring methods, and (2) by examining the effect on the point prevalence of disease using different threshold values of the AHI. DESIGN: Retrospective analysis of 48 diagnostic polysomnographic records. SETTING: Tertiary-hospital sleep-disorders clinic. MEASUREMENTS: AHIs were derived from three different methods for scoring hypopneas. The hypopnea definitions used incorporated different combinations and threshold values of respiratory signal changes in addition to differences in the requirement for associated oxygen desaturation or arousal. The level of agreement between different scoring methods was assessed by constructing Bland-Altman plots and calculating intraclass correlation coefficients (ICCs). kappa statistics were used to assess agreement between the different methods using varying thresholds of AHI to categorize sleep apnea (AHI > 5, AHI > 15, and AHI > 20). RESULTS: The random-effects ICC for the three methods was 0.89, suggesting that the different scoring methods tended to rank patients fairly consistently. However, the point prevalence of disease estimated by using different thresholds of AHI was found to vary depending on the method used to score sleep studies (kappa, 0.30 to 0.95). CONCLUSIONS: These findings have implications for case finding, population-prevalence estimates, and grading of disease severity for access to government-funded continuous positive airway pressure services. Guidelines for standardizing the measurement and reporting of sleep studies in clinical practice should be implemented.     

高血压合并OSAHS动态动脉硬化指数与呼吸暂停低通气指数的关系

目的探讨高血压合并阻塞性睡眠呼吸暂停综合征(OSAHS)患者动态动脉硬化指数(AASI)与呼吸暂停低通气指数(AHI)的关系。方法选择高血压患者153例,根据AHI值分为实验组(OSAHS组,79例)和对照组(非OSAHS组,74例),收集所有患者年龄、性别、身高、体重、24 h动态血压监测数据、AHI值以及冠心病、高脂血症、2型糖尿病患病情况,计算出AASI值,比较两组AASI值的差别,分析AASI值与AHI值的相关性。结果实验组AASI值高于对照组(0.599±0.118 vs 0.381±0.098),差异有统计学意义(P0.05),实验组AASI值与AHI值呈正相关(r=0.617,P0.01),对照组AASI值与AHI值无相关性。结论高血压合并OSAHS患者动脉硬化程度较单纯高血压患者严重且与OSAHS严重程度呈正相关。     

The correlation among obesity, apnea-hypopnea index, and tonsil size in children

BACKGROUND: The correlation between obesity and severity of obstructive sleep apnea (OSA) is well established in adults, but data are inconsistent in children. We hypothesized that there is a significant correlation between the degree of obesity and the severity of OSA in children. METHODS: We retrospectively reviewed records of weight, height, history, and polysomnography of all 1- to 15- year-old children referred to our sleep laboratory. Children with known anomalies and repeated polysomnography were excluded from this study. Obesity was defined as body mass index z score (BMI Z score) > 1.96. The correlation between BMI Z score and apnea-hypopnea index (AHI) was assessed. Possible confounding factors, ie, age, gender, and tonsil size, were adjusted by multiple linear regression. RESULTS: Four hundred eighty-two children were included in this study. Obese children had a significantly higher AHI (median, 1.5; interquartile range [IQR], 0.2 to 7.0) than the AHI of nonobese children (median, 0.7; IQR, 0.0 to 2.5). BMI Z score was significantly correlated with log-transformed AHI (Ln[AHI]) [r = 0.156, p = 0.003]. BMI Z score and tonsil size were still correlated with Ln(AHI) even after adjusted for other confounding factors (p = 0.001). CONCLUSION: Degree of obesity as measured by BMI Z score and tonsil size are significantly related to severity of OSA as reflected by the AHI, although the correlation is mild.     

Prediction of obstructive sleep apnea: comparative performance of three screening instruments on the apnea-hypopnea index and the oxygen desaturation index

Sleep and Breathing - To evaluate the performance of the NoSAS&nbsp;(neck, obesity, snoring, age, sex) score, the STOP-Bang&nbsp;(snoring, tiredness, observed apneas, blood pressure, body...     

采用肥胖参数筛查和诊断老年男性阻塞性睡眠呼吸暂停低通气综合征的研究

目的 应用受试者工作特征曲线(receiver operating characteristic curve,ROC curve)探讨体质指数(BMI)、颈围、腰围及腰臀比等各种肥胖参数筛查、诊断老年男性阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的参考切点并比较其价值. 方法 分析402例老年男性患者的BMI、颈围、腰围及腰臀比与呼吸暂停低通气指数(apnea-hypopnea index,AHI)间的相关性;用ROC曲线确定BMI、颈围、腰围、腰臀比等肥胖参数筛查、诊断OSAHS的参考切点;用ROC曲线下面积(Area under curve,AUC)判断各肥胖参数的整体准确性. 结果 (1)老年男性BMI、颈围、腰围及腰臀比均与AHI呈正相关,其相关系数分别为0.241、0.201、0.210、0.097,P值分别为0.000、0.000、0.000、0.053;BMI、颈围、腰围及腰臀比ROC曲线下面积分别为:0.61、0.58、0.51、0.45,P值分别为0.001、0.060、0.840、0.250;BMI可用于筛查、诊断老年男性OSAHS;颈围、腰围、腰臀比尚不足以用于筛查、诊断老年男性OSAHS;(2)灵敏度达90%,漏诊率10%时,BMI筛查OSAHS的切点为22.0kg/m~2;(3)特异度达90%,误诊率10%时,BMI确诊OSAHS的切点为29.0 kg/m~2. 结论 BMI≥22.0 kg/m~2可作为筛查老年男性OSAHS的参考标准;BMI≥29.0 kg/m~2可作为诊断老年男性OSAHS的参考标准.     

不同体质量指数及性别对阻塞性睡眠呼吸暂停低通气综合征患者影响的研究进展

阻塞性睡眠呼吸暂停低通气综合征(OSAHS)是最常见的睡眠障碍疾病,会对人体不同器官造成影响,心血管受累尤为严重.持续气道正压通气治疗是目前OSAHS治疗中应用最广泛且有效的方法,可以有效改善患者缺氧严重程度及睡眠情况.OSAHS的发病、严重程度及其预后受年龄、性别和体质量指数(BMI)等多种因素的影响.OSAHS通常...     

Influence of the right- versus left-sided sleeping position on the apnea-hypopnea index in patients with sleep apnea

Purpose

Sleep and sleep position have a significant impact on physical, cardiac and mental health, and have been evaluated in numerous studies particularly in terms of lateral sleeping positions and their association with diseases. We retrospectively examined the relationship between the sleeping position and position-specific apnea-hypopnea index (AHI) in obstructive sleep apnea-hypopnea (OSA) patients.

Methods

We assessed the sleeping body position and the body position-specific AHI score in patients who were referred for suspected OSA and underwent diagnostic nocturnal polysomnography. In order to eliminate inter-individual differences, only those who had a similar percentage of time spent in the LSSP and RSSP for each patient were enrolled. To provide this validity, only subjects that had a similar percentage of left and right lateral sleep time (±10%) were included in the analysis.

Results

A total of 864 patients had nocturnal diagnostic PSG. Of them, 131 patients met the inclusion criteria. The percent rate spent in the supine sleeping position (SSP) was 31.3?±?18.7%, in the LSSP was 31.8?±?10% and in the RSSP was 32.6?±?10.8%. Whereas the SSP-specific AHI score was the highest with 60.4?±?36.2/h among all the sleeping position-specific AHI scores (p?<?0.001), the LSSP-specific AHI score was statistically higher than that for RSSP (30.2?±?32.6/h vs. 23.6?±?30.1/h; p?<?0.001). When comparing individuals sub-grouped based on OSA severity, there was a statistically significant difference between the LSSP-specific AHI score and RSSP-specific AHI score in patients with severe (p?=?0.002) and moderate (p?=?0.026), but not mild (p?=?0.130) OSA.

Conclusion

We found that the sleeping position had a significant influence on apneic events and RSSP decreased the frequency of obstructive respiratory events in patients with moderate and severe disease.     

阻塞性睡眠呼吸暂停低通气综合征患者不同程度氧减指数与肾功能早期损害

目的探讨阻塞性睡眠呼吸暂停低通气综合征(obstructive sleep apnea-hypopnea syndrome, OSAHS)不同程度的氧减指数(oxygen reduction index, ODI)与患者早期肾功能损害的关系。 方法选取经多导睡眠(polysomnography, PSG)监测并诊断为OSAHS的患者187例,按照不同ODI区间(轻度5≤ODI<15、中度15≤ODI<30、重度ODI≥30)分为3组,比较3组患者在血清胱抑素C(serum cystine C, sCys-C)、血清尿素氮(blood urea nitrogen, BUN)、血清肌酐(serum creatinine, SCr)、血清β₂微球蛋白(serum β2 microglobulin, β₂-MG)、超氧化物歧化酶(superoxide dismutase, SOD)、尿N-乙酰-β-D氨基葡萄糖苷(N-acetyl-β-d glucosamine, NAG)方面的差异及相关性。 结果各组间相关性分析发现,ODI指数与AHI、BMI、性别、高血压发病率存在明显正相关。各组患者指标分析中sCys-C、β₂-MG、SOD、尿NAG随着ODI指数升高有明显升高趋势,组间比较有统计学意义(P<0.05);ODI与sCys-C、β₂-MG、尿NAG呈正相关,与SOD水平呈负相关。 结论重度ODI升高的OSAHS患者存在肾功能的早期损害。     

Clinical evaluation of a new ear oximeter

Ear oximetry offers a noninvasive method of determining and monitoring oxygen saturation in arterialized capillary blood. A new apparatus has recently been developed which provides improved accuracy as well as increased ease of use. We have found it to be at least as accurate as the American Optical oximeter which measures oxygen saturation directly from arterial blood. It has proved to be of value in clinical situations such as monitoring critically ill patients (particularly those being mechanically ventilated) and patients undergoing treadmill exercise or fiberoptic bronchoscopy and in the diagnosis of disorders characterized by periodic hypoxia.