对比呼气负压与传统方法检测慢性阻塞性肺疾病患者呼气气流受限

目的 对比呼气负压(NEP)与传统方法 检测慢性阻塞性肺疾病(COPD)患者呼气气流受限(EFL).方法 应用NEP与传统方法 (层流型流最计)检测72例COPD缓解期患者EFL;对20例不能完成传统测试的患者应用NEP检测其EFL;对比两种方法 的检测结果 .结果 72例COPD患者应用NEP 54例(75%)检测到EFL.第1秒用力呼气容积(FEV_1)占预计值百分比EFL评分2分者为(46.92±12.74)%,3分者为(33.35±8.96)%,显著低于EFL评分1分者[(63.60±16.65)%].ROC曲线分析NEP曲线下面积(AUC)为0.903,层流型流量计AUC为0.761.20例不能完成传统测试的患者均能耐受NEP测试,19例检测到EFL.结论 应用NEP检测COPD患者EFL,比应用传统方法 检测更能准确反映COPD患者呼吸困难的严重程度;NEP操作简单、无需患者主动配合,可在不能完成传统测试的患者中应用.     

呼气流速受限在儿童支气管哮喘气道反应性评价中的应用

自2004年开始我们进行了呼气相气道内负压（NEP）检测呼气流速受限的系列研究^[1-3]，初步证实NEP法检测呼气流速受限能作为评估慢性阻塞性肺疾病（COPD）、支气管哮喘（简称哮喘）患者病情和呼吸困难严重程度的简单、有效方法，并可应用于支气管舒张试验作为评估气道阻塞可逆性的判断指标。但目前有关NEP法检测呼气流速受限在支气管激发试验中的可行性尚不明确，为此，我们探讨NEP法检测呼气流速受限作为儿童支气管激发试验判断指标的可行性。     

呼气负压技术

呼气负压技术 (NEP)是一种非侵袭性的检查手段 ,主要用于检测呼气流速受限。NEP测试包括坐位和卧位测试 ,在平静呼气时于气道开口处施加 -3～ -5cmH2 O的负压 ,将应用负压时出现流速受限后继续呼出的潮气量与未用负压时的呼出潮气量之比 ,称为流速受限指数。NEP技术在自主呼吸状态下进行 ,并适用于机械通气患者 ,有较好的临床应用前景。     

呼气流速受限在支气管舒张试验中的可行性

1994年Valta等首次提出了不需患者主动配合用力呼吸而仅在潮气呼吸下进行的呼气相气道内负压（NEP法）检测呼气流速受限（EFL）的方法，目前采用NEP法检测慢性阻塞性肺疾病（COPD）和支气管哮喘（简称哮喘）患者EFL的相关研究结果提示，EFL比第一秒用力呼气容积（FEV1）能更敏感反映COPD和哮喘患者呼吸困难和病情的严重程度。但目前有关NEP法检测EFL在支气管舒张试验中的可行性尚不明确。我们采用NEP法检测COPD和哮喘患者吸入支气管舒张剂沙丁胺醇前、后EFL的变化，并与常规FEV1判断指标进行比较，探讨NEP法检测EFL在支气管舒张试验中的可行性。     

呼气相气道内负压法检测呼气流速受限在慢性阻塞性肺疾病中的应用

目的探讨慢性阻塞性肺疾病(COPD)患者呼气流速受限(EFL)与呼吸困难严重程度的相关性,并观察吸入支气管扩张剂对 COPD 患者 EFL 的影响。方法采用呼气相气道内负压法(NEP)检测33例 COPD 患者支气管扩张试验前、后(吸入沙丁胺醇400μg)EFL 情况,其中男31例,女2例,年龄46～78岁,平均年龄(63±8)岁。结果 33例 COPD 患者中23例(70%)出现 EFL,其中11例(33%)仅仰卧位出现 EFL,12例(36%)仰卧位及坐位均出现 EFL。无 EFL 患者与 EFL 患者第一秒用力呼气容积占预计值百分比(FEV_1占预计值%)分别为(66±16)%和(31±10)%,差异有统计学意义(t=7.601、P<0.01),仰卧位及坐位均出现 EFL 患者的 FEV_1占预计值%最低[(24±7)%]。3分法和5分法 EFL 均与 FEV_1呈显著负相关(r=-0.836和-0.818,P 均<0.01)。3分法和5分法 EFL 均与医学研究委员会(MRC)推荐的呼吸困难严重程度分级评分标准(简称 MRC 呼吸困难评分)呈显著正相关(r=0.903和0.912,P均<0.01)。多元回归分析结果显示,5分法 EFL 和FEV_1对 MRC 呼吸困难评分的预测性均有统计学意义(标准化偏回归系数分别为0.679、-0.265,P分别为<0.01、0.029),但5分法 EFL 比 FEV_1对 MRC 呼吸困难评分的预测性更强。23例吸入沙丁胺醇前存在 EFL 患者,吸入后全部患者 EFL 仍然存在。结论与 FEV_1比较,EFL 对 COPD 患者呼吸困难严重程度预测性更强,可作为评价 COPD 患者呼吸困难严重程度更可靠的客观指标。COPD 患者的 EFL 不能被吸入支气管扩张剂逆转,即表现为 EFL 的不可逆性。     

动态性肺过度充气与COPD患者劳力性呼吸困难的关系

目的探讨动态肺过度充气（DH）与COPD患者劳力性呼吸困难的关系。方法对我院42例COPD稳定期患者和20例健康体检者进行肺功能检测、症状限制递增功率心肺运动试验、高强度恒定功率运动试验,分别记录受试者静息状态和运动中的Borg呼吸困难评分、深吸气量（IC）、潮气量（VT）等指标。结果COPD组患者的呼吸变的浅快,呼气流速降低,呼气时问缩短,运动耐量显著低于对照组;COPD组患者在运动高峰时的Ic显著低于静息状态,对照组运动高峰时Ic与静息状态时无明显差别;COPD组患者运动终点与静息状态时Borg呼吸困难评分的差值（ABorg）与Ic的差值（AIC）呈负相关（r=-0．62,P〈0．05）,VT的差值（AVT）与AIC呈负相关（r=-0．80,P〈0．05）。结论动态性肺过度充气是慢性阻塞性肺疾病患者发生劳力性呼吸困难的原因之一,其产生与呼气呼气流速下降和呼气时间的缩短有关。     

不同指标对老年严重慢性阻塞性肺疾病患者吸入支气管舒张剂疗效的评价

目的 对评价严重慢性阻塞性肺疾病(COPD)患者吸入支气管舒张剂疗效的3种指标进行比较. 方法 吸人复方异丙托溴胺溶液前后对18例稳定期严重COPD患者行肺通气功能和肺容量测定,并采用呼气负压技术同步检测呼气流速受限(EFL). 结果 与安慰剂比较,吸入支气管舒张剂后COPD患者第1秒用力呼气容积占预计值(FEV1)百分比、用力肺活量占预计值(FVC)百分比、深吸气量占预计值(IC)百分比显著改善,残气量占预计值(RV)百分比和功能残气量占预计值(FRC)百分比显著降低,肺总量占预计值(TLC)百分比无显著改变;Borg呼吸困难评分显著降低;5分法EFL评分无显著改变,呼吸方式无显著改变.IC、FEV,和5分法EFL评分的平均改善率分别是(20.42±15.02)%、(10.98±7.28)%和(5.15±11.24).△IC与ABorg呈负相关(r=0.732,P<0.05),AFEVl与ABorg相关关系无统计学意义(r=0.343,P>0.05).应用受试者工作特征曲线方法分析3种不同指标诊断呼吸困难的价值,结果表明,IC、FEV1和5分法EFL评分的曲线下面积分别为0.868、0.681和0.557. 结论 与FEV1相比,IC评价严莺COPD患者支气管舒张剂疗效更为灵敏和准确,5分法EFL评分不宜作为评价严重COPD患者吸人支气管舒张剂疗效的指标.     

COPD患者呼气峰流速与BODE指数的相关性研究

目的探讨PEF与BODE指数的相关性,为基层医院临床评估病情、预后及防治提供依据。方法选取COPD稳定期患者80例,每位受试者完成肺功能检查,BODE指数评分及最大呼气峰流速检查,分析呼气峰流速与BODE指数的相关性。结果呼气峰流速与BODE指数及其各部分评分均有较好的相关性(P<0.05)。结论 PEF能较好的预测BODE指数,可用于基层评估COPD患者的疾病严重程度及预后。     

不同营养比例饮食支持治疗对COPD患者生活质量的影响

目的研究不同营养比例饮食支持治疗对COPD患者生活质量的影响。方法将60例稳定期COPD患者随机分成三组,即常规组、蛋白组、脂肪组各20例,按不同营养比例制定相应食谱,比较各组实验后16周各项研究指标的变化。结果实验后16周蛋白组与常规组、脂肪组比较：肺功能检查提示FEV1%（第一秒用力呼气容积及占预计值百分比）、FEV1/FVC%（第1秒用力呼气容积占用力肺活量的百分比）蛋白组高于常规组、脂肪组,差异有统计学意义（P〈0.05）;SF-36评分蛋白组优于常规组、脂肪组,差异有显著统计学意义（P〈0.01）;测定6 min步行距离蛋白组优于常规组、脂肪组,差异有显著统计学意义（P〈0.01）。结论摄入蛋白相对丰富的饮食为COPD患者较为理想的营养支持方式。     

重度COPD患者肺功能曲线形态分析关于一个新的参数的探讨

目的根据重度慢性阻塞性肺疾病（COPD）患者肺功能曲线的形态特点，总结出一个新的描述患者阻塞程度的一个参数，初步探讨这个参数的合理性和肺动脉压的关系。方法选取重度COPD患者50例，应用肺功能仪测定患者的最大呼气流量容积曲线（MEFV），在呼气支选取一个拐点，计算此点的相对应的流速和呼出气量，测量自定义的α角，测定一部分患者的肺动脉压，对数据进行分析。结果重度COPD患者MEFV呼气支拐点对应的流速和流量与呼气1秒时的流速和流量正相关，α角大小与肺动脉压负相关。结论COPD患者的MEFV呼气支拐点有特殊的病理意义，代表气流阻塞、气道陷闭的时刻和程度，自定义的角α有一定的合理性。     

Flow limitation and dynamic hyperinflation during exercise in COPD patients after single lung transplantation

STUDY OBJECTIVE: Using the negative expiratory pressure (NEP) method, we have previously shown that patients receiving single lung transplantation (SLT) for COPD do not exhibit expiratory flow limitation and have little dyspnea at rest. In the present study, we assessed whether SLT patients exhibit flow limitation, overall hyperinflation, and dyspnea during exercise. METHODS: Expiratory flow limitation assessed by the NEP method and inspiratory capacity maneuvers used to determine end-expiratory lung volume (EELV) and end-inspiratory lung volume (EILV) were performed at rest and during symptom-limited incremental cycle exercise in eight SLT patients. RESULTS: At the time of the study, the mean (+/- SD) FEV(1), FVC, functional residual capacity, and total lung capacity (TLC) amounted to 55 +/- 14%, 67 +/- 12%, 137 +/- 16%, and 110 +/- 11% of predicted, respectively. At rest, all patients did not experience expiratory flow limitation and were without dyspnea. At peak exercise, the maximal mechanical power output and maximal oxygen consumption amounted to 72 +/- 20% and 65 +/- 8% of predicted, respectively, with a maximal dyspnea Borg score of 6 +/- 3. All but one patient exhibited flow limitation and dynamic hyperinflation; the EELV and EILV amounted to 74 +/- 5% and 95 +/- 9% TLC, respectively. The patient who did not exhibit flow limitation during exercise had the lowest dyspnea score. CONCLUSION: Most SLT patients for COPD exhibit expiratory flow limitation and dynamic hyperinflation during exercise, whereas maximal dyspnea is variable.     

Effect of heliox breathing on dynamic hyperinflation in COPD patients

BACKGROUND: and objective: Patients with COPD exhibit increased inspiratory work and dyspnea due to dynamic hyperinflation caused by expiratory flow limitation. Helium-oxygen mixtures (ie, heliox) have been used in treating these patients on the assumption that, by lowering airway resistance, they might be beneficial. METHODS: In 22 patients with COPD, the presence of expiratory flow limitation was assessed with patients in the sitting and supine positions using the negative expiratory pressure technique, and the effects of heliox (80% He, 20% O2) on breathing pattern, expiratory flow limitation, and dynamic hyperinflation, evaluated from the change in inspiratory capacity (IC), were measured at rest and were compared with those due to inhaled salbutamol. RESULTS: During air breathing, 13 patients experienced flow limitation while in the sitting position and 18 experienced flow limitation while in the supine position. Neither heliox nor salbutamol therapy changed the breathing pattern in any of the patients, regardless of posture and the presence or absence of expiratory flow limitation. However, in both positions IC increased significantly in most flow-limited patients after bronchodilator administration, but not after heliox administration. CONCLUSIONS: Since heliox had no effect on dynamic hyperinflation, the use of this gas mixture, which is costly and cumbersome, does not appear to be beneficial in stable patients with COPD breathing at rest.     

Does negative expiratory pressure (NEP) during spontaneous breathing predict respiratory impairment in elderly?

OBJECTIVE: The purpose of this study is to assess whether expiratory flow limitation (FL), as measured by applying a negative pressure at the mouth during tidal expiration, can evaluate the respiratory impairment in elderly patients. METHODS: The study was carried out in 67 consecutive elderly inpatients (24 men and 43 women). Negative expiratory pressure (NEP) of -5 (NEP 5) and -10 (NEP 10) cm H2O were applied during spontaneous tidal expiration. According to the results of the NEP technique, the patients were stratified in two categories: not flow limited and flow limited. We realized then classic forced expiratory manoeuvres (FEV1, FVC) and clinical evaluation of dyspnea (NYHA). According to the values of the lung function data, elderly patients were then divided in 3 groups (normal, obstructive, restrictive). RESULTS: The sensitivity, the specificity, the positive and negative predictive values for the diagnosis of obstructive syndrome by the presence of flow limitation during NEP 5 were 53, 74, 45, 79% respectively and 58, 83, 58, 83% respectively during NEP 10. These findings show that the correlation between FL obtained by the NEP technique during spontaneous breathing and spirometry is not very good despite the fact that both were well correlated with dyspnea score. CONCLUSIONS: In clinical practice, faced with an elderly dyspneic patient unable to perform maximal expiratory manoeuvres, the evaluation of flow limitation by NEP technique seems nor to be reliable to predict an obstructive functional impairment nor to be able to explain the origin of his dyspnea.     

Expiratory flow limitation detected by forced oscillation and negative expiratory pressure.

The within-breath change in reactance (Delta(rs)) measured by forced oscillation technique (FOT) at 5 Hz reliably detects expiratory flow limitation in chronic obstructive pulmonary disease (COPD). The present study compared this approach to the standard negative expiratory pressure (NEP) method. In total, 21 COPD patients were studied by applying both techniques to the same breath and in 15 patients the measurements were repeated after bronchodilator. For each patient and condition five NEP tests were performed and independently scored by three operators unaware of the FOT results. In 180 tests, FOT classified 53.3% as flow limited. On average, the operators scored 27.6% of tests flow limited and 47.6% non-flow limited, but could not score 24.8%. The methods disagreed in 7.9% of cases; in 78% of these the NEP scores differed between operators. Bronchodilation reduced NEP and DeltaX(rs) scores, with only the latter achieving significance. Averaging the operators' NEP scores, a threshold between 24.6-30.8% of tidal volume being flow limited by NEP produced 94% agreement between methods. In conclusion, when negative expiratory pressure and forced oscillation technique were both available they showed good agreement. As forced oscillation technique is automatic and can measure multiple breaths over long periods, it is suitable for monitoring expiratory flow limitation continuously and identifying patients' breathing close to the onset of expiratory flow limitation, where intermittent sampling may be unrepresentative.     

Factors Discriminating Spontaneous Pursed-Lips Breathing Use in Patients with COPD

ABSTRACT

Pursed-lips breathing (PLB) is often spontaneously performed by chronic obstructive pulmonary disease (COPD) patients. The aim of this study was to evaluate spontaneous PLB prevalence and to identify factors discriminating its use. Fifty-seven patients with COPD (FEV₁ = 44.3 ± 17.4%pred) underwent pulmonary function testing and two incremental bicycle exercise tests. Peak workload (Wpeak), oxygen uptake (VO₂peak), breathing pattern, and dyspnea (Borg scale) were measured in the first exercise test and spontaneous PLB performance in the second. Six patients spontaneously performed pursed-lips breathing during rest (PLBrest), exercise and recovery, 18 during exercise and recovery (PLBex), 7 during recovery only (PLBrec), 20 not at all (PLBno), and 6 performed other expiratory resistive maneuvers. PLBrest and PLBex patients exhibited a lower Wpeak, O₂ uptake, and minute ventilation (V_E), greater expiratory flow limitation and higher slopes relating dyspnea to V_E or W (%predicted). PLBrest patients were more hypercapnic, had a lower exercise tolerance and diffusion capacity, and greater flow limitation and hyperinflation. PLBrec and PLBno patients were indistinguishable with regard to pulmonary function, dyspnea, and exercise performance. The most significant independent predictors of spontaneous PLB use during exercise were FEV₁/FVC and the slope relating dyspnea to V_E. Spontaneous PLB is most often performed by COPD subjects when ventilation is stimulated by exercise, and during recovery from exercise. Severity of airflow obstruction and the dyspnea experienced during exercise play an important role in determining whether or not PLB is spontaneously performed by COPD patients.     

Principal component analysis of various respiratory function tests: the relationship between factor score and severity of pulmonary circulatory disorder in chronic obstructive pulmonary disease

The relationship between pulmonary haemodynamics and values of various respiratory function tests was studied in patients with mild chronic obstructive pulmonary disease (COPD) and the following results were obtained. (1) The value of mean pulmonary artery pressure (mPAP) at rest in COPD patients was slightly elevated to 19.4 mmHg on average compared with our control value of less than 18 mmHg. (2) Analysis of the data of 11 routine respiratory function tests in 88 COPD patients extracted two principal components: an index of the expiratory function and an index for overinflation of the lung. (3) In individual patients, mPAP expressed the severity of pulmonary circulatory disorder roughly inverse to the factor score of the first principal component (index of expiratory function) but not to that of the second principal component (overinflation of the lung). (4) Discriminant analysis was performed in all 88 COPD patients according to data from the 11 respiratory function tests. The probability of mPAP being above or below 18 mmHg was 18.2%. (5) The relationship between the predicted EPOI value and the factor score was similar to that between mPAP and the factor score. EPOI (exercise pulmonary artery pressure-oxygen consumption index) was calculated with the following equation: EPOI = (mPAPex#-mPAPrest)/[VO2ex-VO2rest)/BSA##). On the other hand, EPOIpred was calculated with the prediction equation obtained from multiple linear regression (dependent variable; EPOI, independent variable; respiratory function).     

Expiratory flow limitation in patients with pleural effusion

BACKGROUND: Expiratory flow limitation (EFL) is one of the main mechanisms contributing to dyspnea in patients with chronic obstructive pulmonary disease but has not been explored in patients with pleural effusion. OBJECTIVES: It was the aim of this study to determine whether patients with pleural effusion exhibit EFL and to investigate the effect of therapeutic thoracentesis on EFL. PATIENTS AND METHODS: The study was performed on 21 patients with pleural effusion who were subjected to thoracentesis and measurement of pleural pressure (PP). Spirometry and estimation of flow limitation by the negative expiratory pressure technique were performed before and after thoracentesis. RESULTS: Statistically significant differences were observed in all spirometric parameters. No correlation between the increase in lung volumes and flows and any of the aspirated fluid parameters was observed. Before thoracentesis, 14 out of 21 patients were flow limited, compared with 7 patients after thoracentesis (chi(2) = 6.151, p = 0.013). Mean values of flow limitation before and after thoracentesis differed significantly. The decrease in flow limitation did not correlate with the increase in the spirometric parameters, the aspirated fluid volume or PP decrease. CONCLUSIONS: In the majority of patients with pleural effusion, flow limitation improves after thoracentesis. Flow limitation may be a contributing factor to the sensation of dyspnea in these patients.     

Role of inspiratory capacity on exercise tolerance in COPD patients with and without tidal expiratory flow limitation at rest.

Expiratory flow limitation promotes dynamic hyperinflation during exercise in chronic obstructive pulmonary disease (COPD) patients with a consequent reduction in inspiratory capacity (IC), limiting their exercise tolerance. Therefore, the exercise capacity of patients with tidal expiratory flow limitation (FL) at rest should depend on the magnitude of IC. The presented study was designed to evaluate the role of FL on the relationship between resting IC, other respiratory function variables and exercise performance in COPD patients. Fifty-two patients were included in the study. Negative expiratory pressure (NEP) uptake (VO2,max) were measured during an incremental symptom-limited cycle exercise. Twenty-nine patients were FL at rest. The IC was normal in all non-FL patients, while in most FL subjects it was decreased. Both WRmax and VO2,max were lower in FL patients (p<0.001, each). A close relationship of WRmax and O2,max to IC was found (r=0.73 and 0.75, respectively; p<0.0001, each). In the whole group, stepwise regression analysis selected IC and forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) (% predicted) as the only significant contributors to exercise tolerance. Subgroup analysis showed that IC was the sole predictor in FL patients, and FEV1/FVC in non-FL patients. Detection of flow limitation provides useful information on the factors that influence exercise capacity in chronic obstructive pulmonary disease patients. Accordingly, in patients with flow limitation, inspiratory capacity appears as the best predictor of exercise tolerance, reflecting the presence of dynamic hyperinflation.