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。     

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.     

呼气相气道内负压法检测呼气流速受限应用于儿童支气管激发试验的可行性

目的 观察支气管哮喘(简称哮喘)患儿支气管组胺激发试验前、后呼气流速受限(EFL)情况,并与常规的以第1秒用力呼气容积(FEV1)作为判断指标的支气管激发试验结果进行比较,探讨EFL作为支气管激发试验判断指标的可行性.方法 非急性发作期哮喘30例患儿,采用呼气相气道内负压(NEP)法检测患儿支气管组胺激发试验前、后EFL情况.结果 30例非急性发作期哮喘息儿中,支气管组胺激发试验阳性者(BPT阳性组)19例,阴性者(BPT阴性组)11例.BPT阳性患儿激发前、后FEV1分别为(1.71±0.52)L和(1.21±0.34)L,FEV1下降率为(29.04±7.49)%,19例BPT阳性患儿激发前和激发后分别有1例和3例出现卧位EFL,坐位时均无EFL,患儿3分法EFL和5分法EFL激发前(分别为1.05±0.23和0.05±0.22)与激发后(分别为1.16±0.37和0.26±0.65)比较差异均无统计学意义(t分别为1.455和1.714,P分别为0.163和0.104).BPT阴性患儿激发前、后FEV1分别为(1.89±0.80)L和(1.79±0.78)L,FEV1下降率为(6.09±5.29)%,11例BPT阴性患儿激发前与激发后均无EFL.结论 NEP法检测EFL不能敏感反映传统支气管激发试验阳性判断标准(FEV1下降≥20%)的变化,其在支气管激发试验中的可行性和阳性判断标准尚有待进一步研究探讨.     

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。     

β2-AR多态性对COPD患者支气管舒张反应的影响

目的探讨β2-肾上腺素能受体(β2-AR)编码区16位点基因多态性对慢性阻塞性肺病(COPD)支气管舒张反应的影响.方法用直接测序法确定34例COPD患者的基因型,其中野生型组(Arg16Arg)16例、突变型组(Arg16Gly+Gly16Gly)18例;以1秒钟用力呼气量(FEV1)占预计值%为指标,分别吸入沙丁胺醇、溴化异丙托品及两药联合,观察药物吸入前及吸入后15、30、60、120、180、360分钟FEV1占预计值%的变化,分析基因多态性对支气管舒张反应的影响.结果吸入沙丁胺醇后,野生型组FEV1占预计值%平均改善率及最大改善率都强于突变型组,差异有显著性(P均＜0.05);突变型组吸入溴化异丙托品后的FEV1占预计值%平均改善率高于吸入沙丁胺醇后,差异有显著性(P＜0.05);两药联合吸入时患者FEV1占预计值%平均改善率分别强于吸入沙丁胺醇和溴化异丙托品后(P均＜0.05).结论β2-AR16位点多态性是影响COPD吸入沙丁胺醇、溴化异丙托品后支气管舒张反应性的重要原因之一.     

哮喘患者氧化/抗氧化系统的变化及意义

为探讨支气管哮喘(哮喘)患者体内氧化/抗氧化系统的变化及其与哮喘的相关性,选择40例非急性发作期哮喘患者、20例健康人(对照组),用放射免疫法和分光光度法测定血清超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量,同时测定1秒种用力肺活量实测值和预计值百分比(FEV1%).结果显示,哮喘患者SOD、CAT活性低于对照组(P＜0.01,P＜0.05);MDA含量高于对照组(P＜0.01);哮喘患者MDA含量与FEV1%呈显著负相关(P＜0.01);哮喘患者吸入沙丁胺醇治疗后MDA含量减低(P＜0.05),沙丁胺醇 必可酮吸入治疗者较单独吸入沙丁胺醇治疗者SOD活性升高(P＜0.05),MDA含量下降(P＜0.05).表明氧化/抗氧化系统失衡是哮喘发病的重要机制之一,应用β2-受体兴奋剂及吸入糖皮质激素均可减少氧化物的产生.     

呼气相负压检测呼气流速受限对阻塞性睡眠呼吸暂停低通气综合征的评价

目的　探讨呼气相气道内负压（NEP）检测阻塞性睡眠呼吸暂停/低通气综合征（OSAHS）患者呼气流速受限（EFL）作为评估上气道塌陷性指标的可行性及其与OSAHS严重度的相关性。方法　采用NEP法（-5cmH2O）检测OSAHS患者及健康对照者仰卧位和坐位EFL情况。OSAHS组33例,均为男性,平均年龄（47±12）岁;健康对照组20例,男15例,女5例,平均年龄（42±10）岁。结果　20例健康对照组均无EFL。33例OSAHS患者中10例（30.3%）检测出EFL,其中15例轻中度OSAHS组仅1例（6.7%）出现EFL,而18例重度OSAHS组9例（50%）出现EFL,两组间EFL发生率差异有统计学意义（P〈0.01）。EFL组呼吸暂停低通气指数（AHI）、呼吸暂停总次数（TNA）和低氧指数（DI）均显著高于无EFL组（分别为65.66±22.20和36.50±21.74、372.60±214.46和173.39±133.65、65.18±23.22和38.59±22.02,P均〈0.01）,而夜间最低氧饱和度（NNSp）显著低于无EFL组（58.80±12.78和71.00±9.30,P〈0.01）。3分法和5分法EFL均与AHI、DI、TNA呈显著正相关（3分法EFL的相关系数分别为0.548、0.513、0.472,5分法EFL的相关系数分别为0.560、0.524、0.469,P均〈0.01）,与NNSp呈显著负相关（相关系数分别为-0.514和-0.508,P均〈0.01）。多元回归分析结果显示,5分法EFL对AHI和DI均有显著预测意义（标准化偏回归系数分别为0.495和0.402,P均〈0.01）。结论　采用NEP法在清醒状态下检测EFL可在一定程度上反映OSAHS患者上气道塌陷性增加及OSAHS病情严重程度,可望成为OSAHS初筛诊断和动态观察评估病情严重程度及疗效的简便、可靠的方法。     

吸入沙丁胺醇对慢性阻塞性肺疾病患者呼气流速受限的影响

目的　评价吸入支气管扩张剂治疗对慢性阻塞性肺疾病 (COPD)患者呼气流速受限 (EFL)的影响。方法　 2 8例稳定期中、重度COPD患者在吸入沙丁胺醇干粉剂前后行常规肺功能测定和呼气负压 (NEP)测试。结果　NEP测试显示所有患者均存在EFL。吸入沙丁胺醇后FEV1 ,FVC和FEF50 iso vol均有显著增高 ,流速受限 (FL)指数则明显下降〔(79.1± 1 2 .0 ) %与 (63 .2± 1 2 .9) % ,P <0 .0 1〕。 1 1例COPD患者的FEV1 ≥ 1 5 % (阳性组 ) ,其余1 7例FEV1 <1 5 % (阴性组 ) ,两组患者的FEF50 iso vol和FL指数则无明显差异 (FEF50 iso vol为 (43 .3± 2 0 .2 ) %与 (39.6± 2 1 .7) % ,FL指数为〔(2 1 .5± 8.4) %与 (1 9.6± 1 1 .7) % ,均P >0 .0 5〕。FL指数与ΔFEF50 % iso vol呈显著相关(r =0 .50 8,P <0 .0 1 ) ,而与FEV1 的相关性不明显 (r=0 .1 0 6 ,P >0 .0 5)。结论　COPD患者在吸入支气管扩张剂后其EFL可得到显著改善 ,FVC和FEV1 均显著增加 ,EFL的改善程度相当于FEF50 %的改变程度     

呼气相气道内负压法检测呼气流速受限应用于儿童支气管激发试验的可行性

目的观察支气管哮喘（简称哮喘）患儿支气管组胺激发试验前、后呼气流速受限（EFL）情况,并与常规的以第1秒用力呼气容积（FEV1）作为判断指标的支气管激发试验结果进行比较,探讨EFL作为支气管激发试验判断指标的可行性。方法非急性发作期哮喘30例患儿,采用呼气相气道内负压（NEP）法检测患儿支气管组胺激发试验前、后EFL情况。结果30例非急性发作期哮喘患儿中,支气管组胺激发试验阳性者（BPT阳性组）19例,阴性者（BPT阴性组）11例。BPT阳性患儿激发前、后FEV1分别为（1．71±0．52）L和（1．21±0．34）L,FEV1pred％下降率为（29．04±7．49）％,19例BPT阳性患儿激发前和激发后分别有1例和3例出现卧位EFL,坐位时均无EFL,患儿3分法EFL和5分法EFL激发前（分别为1．05±0．23和0．05±0．22）与激发后（分别为1．16±0．37和0．26±0．65）比较差异均无统计学意义（t分别为1．455和1．714,P分别为0．163和0．104）。BPT阴性患儿激发前、后FEV1分别为（1．89±0．80）L和（1．79±0．78）L,FEV1pred％下降率为（6．09±5．29）％,11例BPT阴性患儿激发前与激发后均无EFL。结论NEP法检测EFL不能敏感反映传统支气管激发试验阳性判断标准（FEV1pred％下降≥20％）的变化,其在支气管激发试验中的可行性和阳性判断标准尚有待进一步研究探讨。     

哮喘患者不同时期血清C反应蛋白测定的临床意义

目的 研究哮喘患者不同时期血清C反应蛋白测定的临床意义.方法 60例哮喘患者(哮喘组)和15名健康对照者(健康对照组)为研究对象,测定哮喘组患者急性发作期、慢性持续期、缓解朗及对照组的血清C反应蛋白、血常规、肺功能及动脉血气.结果 哮喘组患者血清C反应蛋白水平急性发作期明显高于慢性持续期、缓解期及对照组(P均＜0.01).哮喘组急性发作期血清C反应蛋白水平与外周血白细胞总数及动脉血二氧化碳分压(PaCO2)正相关(r分别为0.768、0.694,P均＜0.01),与第1秒用力呼气容积占预计值百分比(FEV1%)、第1秒用力呼气容积占用力肺活量百分比(FEV1/FVC%)及动脉血氧分压(PaO2)负相关(r分别为-0.563、-0.674、-0.528,P均＜0.01).结论 血清C反应蛋白可作为判断哮喘患者病情的一个炎性反应指标.     

容积二氧化碳图对支气管哮喘患者急性加重分级的意义

目的 探讨容积二氧化碳图(Vcap)参数对支气管哮喘(简称哮喘)诊断的临床价值.方法 2006年7月至2007年5月对64例哮喘急性发作期患者(哮喘组)及20名健康者(健康对照组)进行肺通气功能以及Vcap测定,并依据FEV,占预计值%将哮喘患者分为A组(＞80%,18例)、B组(40%～80%,26例)、c组(＜40%,20例),所有受试者先行Vcap测定,随后完成FEV1占预计值%、FEV1/FVC、FVC占预计值%、最大呼气中段流量(MMEF)占预计值%测定.统计学处理采用SPSS 13.0软件.计量资料采用-x±s表示,计数资料采用卡方检验,计量资料两组间比较采用t检验.肺通气参数与Vcap参数间的相关性采用一元线性回归检验;哮喘组与对照组间的差异采用独立样本t检验;健康对照组及哮喘各亚组间的比较采用单因素方差分析.结果 哮喘组患者FEV1占预计值%、FEV1/FVC、PEF占预计值%、MMEF占预计值%分别为(52±20)%、(50±10)%、(49±16)%、(28±16)%,与健康对照组[(98±9)%、(80±6)%、(91±15)%、(73±7)%]比较差异有统计学意义(t值分别为6.93～13.29,P均＜0.01);哮喘组患者Ⅱ期斜率(dC2/DV)、Ⅲ期斜率(dC3/DV)、Ⅲ期与Ⅱ期斜率之比(SR23)分别为(19±6)%/L、(2.9±1.2)%/L、(16.8±10.6)%,与健康对照组[(31±8)%/L、(1.0±0.4)%/L,(3.3±1.5)%]比较差异有统计学意义(t值分别为5.09、-6.14、-6.54,P均＜0.01);哮喘B、C组dC2/DV分别为(17±5)%/L、(13±4)%/L,与健康对照组[(31±8)%/L]比较差异有统计学意义(t=-11.82、-16.75,P均＜0.01);哮喘B、C组患者dC3/DV、SR23分别为(3.2±0.8)%/L、(17.2±3.5)%,(4.1±1.2)%/L、(28.3±6.9)%,与健康对照组[(1.0±0.4)%/L、(3.3±1.5)%]比较差异有统计学意义(t值分别为2.16～26.08,P均＜0.01);哮喘A、B、C组间dC3/DV、SR23比较差异有统计学意义(t值分别为0.91～22.18,P均＜0.05);相关分析结果表明dC2/DV与FEV1占预计值%、FEV1/FVC、PEF占预计值%、MMEF占预计值%呈正相关(r值分别为0.69、0.54、0.59、0.54,P均＜0.01);dC3/DV与FEV1占预计值%、FEV1/FVC、PEF占预计值%、MMEF占预计值%呈显著负相关(r值分别为-0.62、-0.45、-0.69、-0.58,P均＜0.01);SR23与FEV1占预计值%、FEV1/FVC、PEF占预计值%、MMEF占预计值%呈显著负相关(r值分别为-0.75、-0.52、-0.74、-0.62,P均＜0.01).结论 Vcap是一种简便易行、可定量评估哮喘患者支气管阻塞严重程度的有效方法.     

Reproducibility of the negative expiratory pressure technique in COPD

BACKGROUND: Tidal expiratory flow limitation (EFL) contributes to chronic dyspnea and exercise intolerance in COPD patients. It can be assessed with the negative expiratory pressure (NEP) technique and is expressed as either the percentage of the tidal volume over which EFL occurs (EFL%Vt) or according to more detailed three-point or five-point scoring systems. The aim of this study was to evaluate the reproducibility of the NEP technique in COPD patients. METHODS: Tidal EFL was evaluated with NEP in 18 subjects with stable COPD (FEV(1) range, 18 to 75% predicted) on two occasions (mean retest interval, 8.2 days) by the same rater. Agreement between testing occasions was assessed with the kappa statistic for the 3-point and 5-point EFL scores, and with the coefficient of repeatability for EFL%Vt. RESULTS: On the first testing occasion, nine subjects had no EFL, four subjects had EFL in the supine position, and five subjects had EFL in the sitting and the supine position. Using the 3-point score, agreement was present in 14 of 18 subjects at time 2 (kappa = 0.66), indicating substantial agreement. Using the 5-point score, agreement was seen in 13 of 18 subjects (kappa = 0.61), also indicating substantial agreement. The reproducibility of EFL%Vt measurements was lower than that required to reliably detect clinical change in both the sitting and supine positions (coefficient of repeatability, 37% and 58%, respectively). CONCLUSIONS: The 3-point and 5-point scores provide a reproducible assessment of EFL in COPD patients. The classification of EFL as a percentage of tidal volume is less reproducible, and large changes are required to be confident that real clinical change has occurred.     

阻塞性睡眠呼吸暂停综合征患者肺功能与夜间低氧血症的关系

目的探讨睡眠呼吸暂停综合征（ＳＡＳ）患者体位及肥胖因素引起的肺功能改变与夜间低氧血症的关系。方法选择确诊为ＳＡＳ患者３４例，分别于坐位和仰卧位检查肺功能和血气分析，整夜多导睡眠仪监测。肺功能、血气指标和理想体重％（ＩＢＷ％）分别与呼吸暂停指数（ＡＩ）、＜９０％Ｔ（ＳａＯ２低于９０％时间占总睡眠时间百分比）进行相关分析。结果患者由坐位改为仰卧位，ＰａＯ２、肺活量（ＶＣ％）、补呼气量（ＥＲＶ）、功能残气量（ＦＲＣ％）、残气容积（ＲＶ％）、肺总量（ＴＬＣ％）均出现有统计学意义的降低。ＡＩ与仰卧位ＶＣ％、ＴＬＣ％呈正相关。＜９０％Ｔ与坐位ＰａＯ２、ＥＲＶ呈负相关。ＩＢＷ％与坐、仰卧位ＶＣ％和ＥＲＶ呈负相关，与坐位ＦＲＣ呈负相关。ＩＢＷ％与＜９０％Ｔ呈正相关。结论伴有肥胖的ＯＳＡＳ患者，体位改变及肥胖因素影响患者肺功能，加重呼吸暂停时的低氧血症     

Expiratory flow limitation is associated with orthopnea and reversed by vasodilators and diuretics in left heart failure

BACKGROUND: In patients with acute left heart failure (LHF), orthopnea has also been related to the occurrence or worsening of expiratory flow limitation (EFL) in the supine position. We wished to assess whether short-term treatment with vasodilators and diuretics was able to abolish supine EFL and whether this could help to control orthopnea in patients with acute LHF. METHODS: In nine nonobese (ie, mean [+/- SD] body mass index, 24 +/- 5 kg/m2), never-smoker patients (two men and seven women; mean age, 77 +/- 7 years) with acute LHF (mean ejection fraction, 43 +/- 15%), we assessed EFL by the negative expiratory pressure method and dyspnea by the Borg scale, with patients in both the seated and supine positions, before and after short-term treatment with vasodilators and diuretics until hospital discharge. Orthopnea was defined as a positive difference in the Borg score between measurements made with the patient in the supine and seated positions. Postural variations in the end-expiratory lung volume were inferred from changes in inspiratory capacity (IC) that were measured under the same circumstances. RESULTS: Before treatment, with the patient in the seated position the mean dyspnea score was 1.5 +/- 0.5, the mean IC was 1.49 +/- 0.38 L, seven patients were non-flow-limited, and two patients were flow-limited. During recumbency, the mean dyspnea score was 2.7 +/- 0.5 (p < 0.01 vs seated position values), the mean IC was 1.66 +/- 0.45 L, and seven patients exhibited EFL. After a mean duration of 17 +/- 8 days of treatment (range, 7 to 28 days), EFL was detected in two patients only in the supine position, IC increased both in the seated position (1.65 +/- 0.34 L; p < 0.01) and the supine position (1.81 +/- 0.41 L; p = 0.07) position, and, although only two patients denied orthopnea, the mean dyspnea score during recumbency actually decreased to 1.9 +/- 1.0 (p < 0.05). CONCLUSIONS: Our results indicate that short-term treatment with vasodilators and diuretics is able to control orthopnea and to remove supine EFL in most patients with acute LHF, suggesting a posture-related increase in bronchial obstruction as the main mechanism of EFL, which appears to play a role in the occurrence and severity of orthopnea in these circumstances.     

Dyspnea perception and reversibility of methacholine-induced unlimited airway narrowing in asthmatics.

The hypothesis was that asthmatics might experience impaired perception of dyspnea and salbutamol-induced reversibility during unlimited airway narrowing. A total of 38 asthmatics (18 to 59 years of age) were examined. All patients underwent the methacholine challenge test. According to the dose-response curve to methacholine, they were categorized as having either unlimited airway narrowing (UAN group) (n = 20) or response plateau (RP group) (n = 18). Reversibility of methacholine-induced bronchoconstriction was measured 20 minutes after the inhalation of 400 microg of salbutamol to compare postbronchodilator FEV1 with baseline FEV1. Dyspnea perception was evaluated using the Borg Scale to calculate a perception score at a 20% decrease in FEV1 (PS20) and the slope alpha of the regression line between the changes in Borg scores and the reduction in FEV1 as percentage of the baseline value. Subjects in the UAN group exhibited significantly lower PS20 compared with the RP group (1.45+/- 0.23 vs. 2.84 +/- 0.35, p = 0.002); the mean of the slope values was higher in the RP group than it was in the UAN group (0.150 +/- 0.015 vs. 0.095 +/- 0.006, p = 0.003). Salbutamol-induced reversibility was significantly lower in the UAN group (81 +/- 1.4 % of baseline FEV1) compared with patients from the RP group (91 +/- 1.1% of baseline FEV1; p < 0.001). In conclusion, asthmatics during methacholine-induced unlimited airway narrowing exhibit diminished perception of dyspnea and lower bronchial reversibility to the baseline 20 minutes after inhalation of salbutamol. This suggests that more careful monitoring of the lung function for timely recognition of asthma deteriorations and adequate bronchodilatory therapy during severe acute attacks should be recommended for such patients.     

Exercise-induced flow limitation, dynamic hyperinflation and exercise capacity in patients with bronchial asthma.

It is known that, in stable asthmatics at rest, tidal expiratory flow limitation (EFL) and dynamic hyperinflation (DH) are seldom present. This study investigated whether stable asthmatics develop tidal EFL and DH during exercise with concurrent limitation of maximal exercise work rate (WRmax). A total of 20 asthmatics in a stable condition and aged 32+/-13 yrs (mean+/-SD) with a forced expiratory volume in one second (FEV1) of 101+/-21% of the predicted value were studied. Only three patients exhibited an FEV1 below the normal limits. On a first visit, patients performed a symptom-limited incremental (20 W.min(-1)) bicycle exercise test. On the second visit, the occurrence of EFL (using the negative expiratory pressure technique) and DH (via reduction in inspiratory capacity) were assessed at rest and when cycling at 33, 66 and 90% of their predetermined WRmax. FEV1 was measured to detect exercise-induced asthma, 5 and 15 min after stopping exercise at 90% WRmax. Only one patient showed EFL at rest, whereas 13 showed EFL and DH during exercise. In these 13 asthmatics, exercise capacity was significantly reduced (WRmax 75+/-9% pred) compared to the seven non-EFL patients (WRmax 95+/-13% pred). Moreover, a significant correlation of WRmax (% pred) to the change in inspiratory capacity (percentage of resting value) from rest to 90% WRmax was found. Tidal EFL during exercise was not associated with exercise-induced asthma, which was detected in only three patients. In conclusion, tidal expiratory flow limitation and dynamic hyperinflation during exercise are common in stable asthmatics with normal spirometric results and without exercise-induced asthma, and may contribute to reduction in exercise capacity.     

Does expiratory flow limitation predict chronic dyspnoea in adults with cystic fibrosis?

Tidal expiratory flow limitation (EFL) may promote dynamic hyperinflation and contribute to chronic dyspnoea. The purpose of this study was to assess the contribution of EFL to chronic dyspnoea in adults with cystic fibrosis (CF). The presence of EFL was determined in 102 adults with stable CF (forced expiratory volume in one second (FEV1) 17.3-91.5% predicted) and 20 age-matched control subjects using the negative expiratory pressure technique. Measurements of inspiratory capacity (IC) and spirometry were performed, and chronic dyspnoea was evaluated using the modified Medical Research Council scale. EFL was present in 34 subjects (33%), with 18 subjects flow limited in the sitting position and 16 subjects flow limited only in the supine position. Flow limitation in the sitting position was associated with older age and lower FEV1 compared with flow-limited supine position and non-flow-limited subjects. A significant reduction in IC accompanied EFL in both the sitting and supine positions. Flow limitation in the sitting position was associated with significantly higher levels of chronic dyspnoea. Ordinal regression analysis indicated that EFL was the best predictor of chronic dyspnoea in a model that included FEV1 % pred. Expiratory flow limitation in cystic fibrosis is associated with reduced forced expiratory volume in one second, older age and dynamic hyperinflation. Expiratory flow limitation significantly contributes to chronic dyspnoea in cystic fibrosis.     

Changes in urinary LTE4 and nasal functions following nasal provocation test with ASA in ASA-tolerant and -intolerant asthmatics

Aspirin-induced asthma (AIA) is a syndrome characterized by intolerance to aspirin (ASA), nasal polyps and bronchial asthma, the metabolic shift of arachidonic acid towards the lipoxygenase pathway and hyper-production of cysteinyl-leukotrienes (cys-LTs) being the current pathogenetic hypothesis. The research for both sensitive indicators and safe diagnostic tests is still attracting. Aim of the study was to measure changes in urinary LTE4 excretion and in nasal function (Resistance-Req, and Volume-Vol, assessed by acoustic rhinomanometry (AR)) following a nasal provocation test (NPT) with ASA:LTE4 measurements have been never previously used to our knowledge for assessing nasal responsiveness to ASA. METHODS: After written consent, 118 mild-to-moderate asthmatics (48 males, mean age 41.8 years+/-11.9SD, range 25-70 years; basal FEV1=80.1% pred.+/-5.8SD) underwent NPT by nasal instillation of ASA (total maximal dose 25 mg). Spirometry, acoustic rhinomanometry (AR; TM Hood Lab., USA) and urinary LTE4 (pg/mg creatinine; Cayman Chemical, MI, USA) were measured in baseline and 2h after the ASA challenge. STATISTICS: t-Test between means+/-sd, assuming P<0.05, and linear regression between all variables considered. RESULTS: In 67 ASA-intolerant asthmatics, FEV1 did not change significantly following NPT (81.7% pred.+/-5.1SD in baseline, 80.5% pred.+/-4.1 after NPT, P=ns) even in the presence of a significant decrease of Vol (11.3 cm3+/-4.1SD in baseline, 5.9 cm3+/-4.2SD after NPT, P=0.003), a substantial increase of Req (0.88 cmH2O/l/min+/-0.11SD in baseline, 2.41 cmH2O/l/min+/-0.77 after NPT, P=0.002), and urinary LTE4 excretion (433.0 pg/mg+/-361.7 in bsln, 858.0 pg/mg+/-471.6 90 min after NPT with L-SA, P=0.04). NPT did not affect FEV1 also in 51 ASA-tolerant asthmatics (89.7% pred.+/-6.9 in bsln, 86.6% pred.+/-4.3 after NPT), but in these subjects also Vol (from 14.9 cm3+/-4.2sd to 14.6 cm3+/-3.8SD), Req (0.38 cmH2O/l/min+/-0.14 in bsln, 0.26 cmH2O/l/min+/-0.2 after NPT, P=ns), and urinary LTE4 (333.1 pg/mg+/-202.8 in bsln, 318.0 pg/mg+/-198.7 after NPT, P=ns) remained unchanged. Only pre-NPT LTE4 values proved related to pre-NPT Req and Vol values (r=0.54 and r=-0.71, respectively), but not to patients' age (R=-0.05), and basal FEV1 (r=0.01). CONCLUSIONS: In ASA-intolerant patients, NPT with lysine-aspirin (L-ASA) only induces a substantial nasal obstruction and enhances urinary LTE4 excretion in the absence of any significant bronchial obstruction. Nasal ASA challenge proves a test absolutely safe for asthma patients suspected of ASA intolerance. Measures of urinary LTE4 excretion contributed significantly to magnify the discriminant and the diagnostic value of NPT.     

Lateral decubitus position generates discomfort and worsens lung function in chronic heart failure

BACKGROUND: Lateral decubitus position is poorly tolerated by heart failure patients. STUDY OBJECTIVES: To evaluated pulmonary function and lung diffusion in heart failure patients in the following five body positions: sitting, prone, supine, and left and right decubitus. SETTING: Heart failure unit of a university hospital. SUBJECTS: We studied 14 chronic heart failure patients in New York Heart Association class III and 14 healthy volunteers. MEASUREMENTS AND RESULTS: After 15 min of a selected position, subjects were evaluated by a discomfort scale, ear oximetry, and pulmonary function, which included FEV1, FVC, vital capacity (VC), alveolar volume, and diffusing capacity of the lung for carbon monoxide (D(LCO)) with subcomponent membrane resistance (DM) and capillary volume. In healthy subjects, we observed a reduction of D(LCO) and capillary volume in both lateral decubiti. Some discomfort was documented in both lateral decubiti when selected positions were compared with the sitting position. In the sitting position, pulmonary function suggested slight restriction ([mean +/- SD] FVC, 89.8 +/- 22.3% predicted; FEV1, 84.7 +/- 16.9% predicted, VC, 88.6 +/- 21.5% predicted; and FEV1/VC, 74 +/- 7) with low D(LCO) (73 +/- 19% predicted). Compared with sitting, lung mechanics were unchanged in prone and supine positions; FEV1, FVC, and FEV1/VC were lower when patients were lying on their side, with unchanged alveolar volume and VC. D(LCO) was similar when comparing sitting, prone, and supine positions, and it was lower in lateral decubitus because of the lower capillary volume (vs sitting) and DM (vs prone and supine). Body position-related FVC and D(LCO) reduction were greatest in the largest hearts (deltaFVC and deltaD(LCO) vs left ventricle diastolic volume R = 0.524, p < 0.05 and R = 0.630, p < 0.02, respectively; deltaFVC and deltaD(LCO) vs cardiothoracic index R = 0.539, p < 0.05 and R = 0.685, p < 0.01, respectively). CONCLUSIONS: In heart failure, lateral decubitus airway obstruction and lung diffusion impairment become greater as heart dimensions increase.