HHT谱分析方法在利用ECG信号检测睡眠呼吸暂停中的应用

目的:根据睡眠呼吸暂停与心率变化的关系,探讨从心电图中检测睡眠呼吸暂停的方法.方法:通过经验模态分解(EMD)技术将一非线性、非稳态过程的心率变异信号分解为一组内在模态函数(IMFs),对每个IMF进行Hilbert变换,获得HRV信号幅度和频率的时间分布,再根据已获得的HH谱,进而得到边际谱,然后提取信号能量的时频分布、瞬时频率、瞬时能量比、瞬时幅度的标准差等特征向量,根据特征向量的变化检测出睡眠呼吸暂停的位置和分布.结果:对同一个体的HRV信号的分析结果显示,正常呼吸阶段HRV信号的特征向量与睡眠呼吸暂停阶段HRV信号的特征向量有明显区别,实验结果证实了本文所提方法的有效性.结论:该检测方法物理意义明确,诊断结果精度高,为睡眠呼吸暂停综合症的早期诊断、监护及预后评估提供了新的分析工具.     

引导呼吸下的呼吸性窦性心律不齐的研究

研究渐进性引导呼吸对呼吸性窦性心率不齐(RSA)的影响。对15名健康成年男性采集引导呼吸率依次为【14次/min—12.5次/min—11次/min—9.5次/min—8次/min—7次/min】状态下的同步心电、呼吸信号,采用提取RSA时、频特征参数的方法来研究渐变性呼吸率对RSA的影响。计算结果显示:表征RSA强度的三个特征参数总体上随着呼吸率的逐渐降低均呈现出增大的变化趋势。RSA代表着呼吸系统对心血管系统的反射调控,此实验结果表明,随着呼吸率的降低,呼吸系统对心血管系统的反射调控作用逐渐增加,提示可通过改变呼吸模式来改善心血管系统的功能。     

基于梯度提升树的ECG-SAS自动识别方法

目的睡眠呼吸暂停综合征(sleep apnea syndrome,SAS)是威胁生命健康的多发病之一,目前判断SAS的方法大多采用多导睡眠图(polysomnography,PSG),但其操作难度大、专业性高,不能有效推广,因此,设计一种自动检测SAS的方法显得尤为迫切和重要。方法本文设计了一种基于梯度提升树(gradient boosting decision tree,GBDT)的算法方案,首先通过信号处理方法提取心电图(electrocardiogram,ECG)数据的心率变异性(heart rate variability,HRV)特征,然后结合上下文相关性策略处理HRV数据训练模型。在得到模型后,采用动态阈值策略微调预测结果。最后统计每小时内的SAS发生次数,得到呼吸暂停低通气指数(apnea-hypopnea index,AHI),完成SAS病情预测。结果本文使用Apnea-ECG数据库的ECG数据验证该算法效果。结果显示,采用本文方案,35个测试样本的SAS单分钟识别率为88. 56%,按照AHI指标,将样本分为健康、轻度、中度、重度4类,其准确率为91. 43%。结论本文所述基于GBDT的ECG-SAS识别方案,可以有效检测SAS事件,评估个体的SAS病情。     

低氧与心率变异性研究进展

高原或运动等生理性低氧或/和临床心血管、呼吸及代谢等疾病病理性缺氧均可改变机体自主神经调节功能,从而导致心率变异性(HRV)变化。HRV对机体功能状态评定、多种疾病的诊断、预后及疗效评价具有重要价值。本综述简要介绍近年来有关低氧与HRV的研究进展。     

呼吸反馈的研究进展

呼吸反馈训练是一种安全、有效、费用低和非侵袭性的治疗过程,能够让患者学会控制和调节被测量的生理反应,并将其调整到健康水平。呼吸反馈被广泛应用于放松疗法、心血管疾病和呼吸相关疾病调节中。分析不同的呼吸参数对生物反馈的影响,总结呼吸反馈在临床中的应用,探讨呼吸反馈的内在机制,阐述生物反馈仪器的现状,最后对呼吸反馈的最新发展趋势和存在的问题展开讨论。     

不同的本征呼吸周期对兔呼吸周期曲线的影响

除吸气抑制反向射外,肺充气通过迷走神经对呼吸中枢可能产生了另一种作用,其作用效果主要体现在呼吸周期的改变上。本文介绍对麻醉和肌肉麻麻痹的大白兔,用不同相位的肺充气的方法,在消除吸气抑制反射,保持吸气周期不变的条件下,通过改变兔的每分通气量来改变本征呼吸周期,研究了本征呼吸周期对呼吸周期曲线的影响。实验结果表明,对于不同的本征呼吸周期,呼吸周期曲线第一个最低点的位置不同,第二个上升段斜率相同,但沿着垂红方向存在上下移动,第二个最低点的位置相同,第三个上升段重合,但终点位置不同。这说明不同的体征呼吸周期使兔的呼吸周期曲线产生了有一定规律的移动。     

睡眠呼吸监测技术的研究进展

睡眠呼吸监测技术对于睡眠呼吸暂停综合征的预防、发现及治疗起着重要作用.简要介绍用于睡眠呼吸暂停综合征的监测设备分级及应用趋势,分析睡眠呼吸监测技术的特点,对睡眠呼吸监测技术的研究方向和发展现状进行了综述.     

呼吸门控放疗中呼吸基线波动对呼吸预测滤波器性能的影响

目的：评估基于瓦里安实时位置管理（RPM）系统的呼吸门控放疗中病人呼吸基线波动对呼吸预测滤波器（BPF）性能的影响。方法：分析20例RPM相位式呼吸门控放疗病例的参考呼吸波形和残余呼吸信号以及共146次治疗时的呼吸波形和残余呼吸信号,作以下处理：（1）将呼吸波形（包括参考和治疗时）经Savitsky-Golay平滑、峰值检测和异常点剔除后得到呼吸基线,计算其标准差做为衡量基线波动强弱的指标,计算各次治疗时基线波动相对于参考基线波动的相对偏差;（2）计算残余呼吸信号（包括参考和治疗时）标准差,将其作为衡量呼吸信号强弱的指标,同样计算各次治疗时残余呼吸相对于参考残余呼吸的相对偏差;（3）对基线波动偏差和残余呼吸信号偏差做Pearson相关性分析。结果：146次治疗中呼吸基线波动偏差最小值和最大值分别为-61.0%、752.3%,四分位数分别为42.8%、90.3%、161.7%;残余呼吸信号偏差最小值和最大值分别为-74.8%、174.0%,四分位数分别为-7.8%、15.1%、48.8%;残余呼吸信号偏差与基线波动偏差之间的相关系数为0.544,差异有统计学意义（P<0.01）;线...     

心率变异性自回归模型分析中确定最佳阶数的方法研究

基于自回归(AR)模型的心率变异性(HRV)分析技术广泛用于自主神经系统功能状态评价,其中AR模型阶数的选择对于HRV分析结果的准确性有重要的影响,本文研究了AR模型最佳阶数的确定方法。从46名健康成年受试者自然呼吸下的心电信号中提取心跳间期时间序列,用最终预测误差最小准则来计算AR模型最佳阶数,用Burg算法求解AR模型系数,并对残差序列进行白化检测来验证AR模型阶数的合理性。将该方法获得的HRV频域参数(包括总功率、低频功率、高频功率、低高频功率比以及标准化低频功率)与Kubios-HRV分析软件计算得到的结果作对照分析。结果表明通过该方法获得的HRV的5个频域参数均与Kubios-HRV分析软件的结果高度相关(相关系数r大于0.95),除总功率指标外,均无显著差异,对应的Bland-Altman图也有大于95%的点分布在一致性界限内。优化的基于AR模型的HRV分析算法能获得准确的HRV分析结果,与常用的HRV分析软件Kubios-HRV的结果有很好的一致性。     

阻塞性睡眠呼吸暂停综合征患者发生心脏事件的临床分析

目的 探讨阻塞性睡眠呼吸暂停综合征(OSAS)患者发生心脏事件的相关因素以及心率变异性的临床分析.方法 选取2013年1月～12月我院收治的153例OSAS患者作为本组研究的观察对象,按照睡眠呼吸暂停通气指数(AHI)将其分为轻度OSAS组46例、中度OSAS组64例以及重度OSAS组43例,同时选取此期间在内容我院行健康体检的50名健康人员作为对照组,对比OSAS患者与对照组的心率变异性(HRV)指标.结果 OSAS患者的SDNN、SDNN5以及rMSSD明显低于对照组,SDANN明显高于对照组,均具有统计学意义(P＜0.05).其中轻度OSAS组的SDNN、SDNN5以及rMSSD明显高于重度OSAS组,SDANN明显低于重度OSAS组,均具有统计学意义(P＜0.05).结论 OSAS患者的心脏事件发生率较高,与HRV变化幅度大有直接关系,治疗中要注意给予相应干预,降低心脏事件的发生.     

Dietary sodium effects on heart rate variability in salt sensitivity of blood pressure

High dietary sodium intake is a risk factor for hypertension, and heart rate variability (HRV) is decreased in hypertension. Effects of dietary sodium intake on HRV of normotensive persons have not, however, been investigated to date. The present study examined effects of low and high sodium diets on blood pressure, heart rate, and HRV in 36 healthy, normotensive women, ages 40-70. Each was placed on a low sodium diet for 6 days followed by a high sodium diet for 6 days. The high salt diet increased mean systolic blood pressure, decreased heart rate, and increased high frequency HRV (HF). Cardiac vagal tone, estimated at baseline from heart period and a time domain estimate of respiratory sinus arrhythmia, was higher in salt-sensitive than salt-insensitive subjects. The finding of increased vagal tone in normotensive persons on high salt intake indicates that dietary sodium status should be considered in behavioral studies of HRV.     

Rhinovirus frequently detected in elderly adults attending an emergency department

The general aim was to investigate the burden of respiratory virus illness in a hospital emergency department, during two different epidemic seasons. Consecutive patients attending an emergency department during two study periods (February/March 2009 and 2010) were enrolled using broad inclusion criteria (fever/preceding fever and one of a set of ICD-9 codes suggestive of respiratory illness); nasopharyngeal washes were tested for the most common respiratory viruses using PCR-based methods. Influenza A virus was detected in 24% of samples collected in February/March 2009, whereas no samples tested positive for influenza during February/March 2010 (pandemic H1N1 Influenza A having circulated earlier in October-December 2009). Rhinovirus (HRV) was detected in 16% and 8% of patients recruited over the two study periods, respectively. Other respiratory viruses were detected rarely. Patient data were then analyzed with specific PCR results, comparing the HRV-positive group with virus-positive and no virus-detected groups. Individuals over 65 years old with HRV presented with signs, symptoms and underlying conditions and were admitted to hospital as often as the other enrolled patients, mainly for dyspnoea and chronic obstructive pulmonary disease acute exacerbation. Conversely, younger individuals with HRV, although presenting with respiratory signs and symptoms, were generally diagnosed with non-respiratory conditions. HRV was detected frequently in elderly patients attending the emergency department for respiratory distress without distinguishing clinical features. Molecular diagnosis of lower respiratory tract infections and surveillance of infectious diseases should include tests for HRV, as this virus is associated frequently with hospitalization of the elderly.     

不同心动周期序列的心率变异频谱分析

利用AR模型谱估计法对三种心动周期序列和同步的呼吸信号进行频谱分析,比较了三种心动周期序列用来分析心率变异性的异同,结果显示dRR(the difference between adjacent RR intervals)序列的功率谱主要表征了心率变异的HF,且改变呼吸条件时其HF/LF值比较敏感,RR序列对心率变异的LF和HF都有很好的反映,rRR(the remained RR sequence with the mean RR value removed)序列也反映了心率变异的LF和HF,但其LF不是很准确.     

Variability of QT interval duration in obstructive sleep apnea: an indicator of disease severity

STUDY OBJECTIVE: To determine OSA-related changes in variability of QT interval duration and in heart rate variability (HRV), and to evaluate the relationship of these parameters to disease severity. DESIGN: Retrospective analysis of diagnostic sleep records. SETTINGS: Clinical sleep laboratory in a hospital setting. PATIENTS: Twenty patients (12 males and 8 females) without significant comorbidities who were undergoing polysomnography were studied. MEASUREMENTS AND RESULTS: Standard heart rate variability measures and QT variability (Berger algorithm) were computed over consecutive 5-minute ECG epochs throughout the night. The effect of sleep stage and the relationship between these parameters and the severity of OSA as determined by the respiratory disturbance index (RDI) were explored. Further, a linear regression model of QT variability was developed. Severity of OSA (RDI) was 49 +/- 28 (range from 17-107) events/ hr. QT variability was the only ECG measure significantly correlated with RDI (both log-transformed; r = 0.6, P = 0.006). Further, QT variability was correlated with the minimum oxygen saturation (r = -0.55, P = 0.01). Sleep stage showed a significant effect on HRV, but not on QT variability. In the regression model, RDI was the strongest predictor of QT variability (R2 increase 38%), followed by high and low frequency power of HRV (R2 increase 10% each). CONCLUSION: Obstructive sleep apnea is associated with changes in QT interval variability during sleep. The variance of beat-to-beat QT intervals correlates more strongly with the severity of OSA (as determined by RDI) than standard measures of heart rate variability, and is correlated with blood oxygenation, but not sleep stage.     

心率波动信号的谱分析及其应用

本文从颇域角度对心率波动(HRN)信号进行分析、处理。为此,首先利用ECG经峰值检测、内插得到3HRN信号,然后对此信号施以基于AR模型的谱估计法。在正常生理情况下说明了呼吸对心率波动的作用,给出了几种不同呼吸状态下,呼吸对心率波动影响的变化。为说明正常生理状态下,心率波动的神经生理机制提供了依据,同时也为此方法的临床使用打下了一定的基础。     

The significance of rhinovirus detection in hospitalized children: clinical,epidemiological and virological features

Recent developments in molecular diagnostic tools have led to the easy and rapid detection of a large number of rhinovirus (HRV) strains. However, the lack of clinical and epidemiological data hampers the interpretation of these diagnostic findings. From October 2009 to January 2011, we conducted a prospective study in hospitalized children from whom samples were taken for the detection of respiratory viruses. Clinical, epidemiological and microbiological data from 644 patients with 904 disease episodes were collected. When HRV tested positive, strains were further characterized by sequencing the VP4/VP2 region of the HRV genome. HRV was the single respiratory virus detected in 254 disease episodes (28%). Overall, 99 different serotypes were detected (47% HRV-A, 12% HRV-B, 39% HRV-C). Patients with HRV had more underlying pulmonary illness compared with patients with no virus (p 0.01), or patients with another respiratory virus besides HRV (p 0.007). Furthermore, cough, shortness of breath and a need for oxygen were significantly more present in patients with HRV infection. Particularly, patients with HRV-B required extra oxygen. No respiratory symptom, except for oxygen need, was predictive of the presence of HRV. In 22% of HRV-positive disease episodes, HRV infection was hospital acquired. Phylogenetic analysis revealed several clusters of HRV; in more than 25% of these clusters epidemiological information was suggestive of transmission within specific wards. In conclusion, the detection of HRV may help in explaining respiratory illness, particular in patients with pulmonary co-morbidities. Identifying HRV provides opportunities for timely implementation of infection control measures to prevent intra-hospital transmission.