Expiratory Flow Limitation and Its Relation to Dyspnea and Lung Hyperinflation in Patients with Chronic Obstructive Pulmonary Disease: Analysis Using the Forced Expiratory Flow-Volume Curve and Critique

Background: Tidal expiratory flow limitation (tEFL) is defined as absence of increase in air flow during forced expiration compared to tidal breathing and is related to dyspnea at rest and minimal exertion in patients with chronic airflow limitation (CAL). Tidal EFL has not been expressed as a continuous variable (0% - 100%) in previous analyses. Objective: To relate the magnitude of tEFL to spirometric values and Modified Medical Research Council (MMRC) score and Asthma Control Test (ACT). Methods: Tidal EFL was computed as percent of the tidal volume (0% - 100%) spanned (intersected) by the forced expiratory-volume curve. Results: Of 353 patients screened, 192 (114 M, 78 F) patients (136 with COPD, 56 with asthma) had CAL. Overall characteristics: (mean ± SD) age 59 ± 11 years, BMI 28 ± 7, FVC (% pred) 85 ± 20, FEV1 (% pred) 66 ± 21, FEV1/FVC 55% ± 10%, RV (% pred) 147 ± 42. Tidal EFL in patients with tEFL was 53% ± 39%. Using univariate analysis, strongest correlations were between tEFL and FVC and between tEFL and RV in patients with BMI < 30 kg/m2. In patients with nonreversible CAL, tEFL was positively associated with increasing MMRC, negatively with spirometric measurements, and positively with RV/TLC. In asthmatics, ACT scores were higher in patients with mean BMI ≥ 28 kg/m2 (p < 0.00014) and RV/TLC values > 40% (p < 0.03). Conclusions: Dyspnea is strongly associated with tEFL and lung function, particularly in patients with nonreversible CAL. Air trapping and BMI contribute to tEFL.

F-V曲线下降支夹角在COPD患者诊治中的综合评估价值

目的:研究流量-容积(flow-volume,F-V)曲线下降支夹角在慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)患者临床表型及病情严重度评估中的临床价值。方法:选取2021年12月—2022年12月在南京医科大学第一附属医院进行肺功能检查的患者共101例,其中,存在F-V曲线下降支夹角的稳定期COPD患者(夹角组)33例,与夹角组第1秒用力呼气容积占预计值百分比(forced expiratory volume in the first second as a percentage of predicted value,FEV1%pred)匹配的无下降支夹角的稳定期COPD患者(无夹角组)38例,既往无心肺疾病,且肺功能检测正常的受试者(对照组)30例。收集并比较各组患者基本资料、临床症状评分[COPD自我评估测试(COPD assessment test,CAT)、改良版英国医学研究委员会呼吸困难问卷(modified medical research council dyspnoea scale,mMRC)]、肺功能参数和运动后指脉氧参数。采用多因素Logistic回归分析F-V曲线下降支夹角的相关因素。采用受试者工作特征(receiver operating characteristic,ROC)曲线分析F-V曲线下降支夹角对COPD随访1年内急性加重的预测价值。结果:夹角组肺功能受损程度严重,第1秒用力呼气容积(forced expiratory volume in the first second,FEV1)和用力肺活量(forced vital capacity,FVC)分别为0.91±0.24、2.11±0.63;夹角组CAT评分、mMRC评分、ΔSpO_(2)高于无夹角组及对照组,步行运动后SpO_(2)L低于无夹角组及对照组,差异有统计学意义(P<0.05);夹角组CAT评分≥12分、m MRC评分≥2分、ΔSpO_(2)≥13%是F-V曲线下降支更易出现夹角的主要相关因素;F-V曲线下降支夹角预测重度稳定期COPD急性加重的曲线下面积为0.777,当角度<129.1°时其预测灵敏度、特异度均为最佳,分别为72.73%、67.35%。结论:F-V曲线呈现下降支夹角的COPD患者其肺功能常严重受损,且更易发生活动后低氧血症和急性加重。因此,COPD肺功能报告中应关注F-V曲线下降支是否存在夹角,以便尽早识别COPD高危人群。

脉冲震荡肺功能检测在小儿支气管哮喘诊疗中的应用价值

目的分析脉冲震荡肺功能(IOS)检测在小儿支气管哮喘诊疗中的应用价值。方法以回顾性分析为法,观察对象为2021年1月至2022年1月入川北医学院附属医院的40例发作期哮喘患儿(A组)、40例缓解期哮喘患儿(B组)、40例健康体检小儿(C组)。3组研究对象均接受IOS检测与最大呼气流量-容积曲线(MEFV)检测,比较3组IOS参数[呼吸道中心阻力(Rc)、共振频率(Fres)、震荡频率为5 Hz时电抗值(X5)、震荡频率为20 Hz时中心气道黏性阻力(R20)、震荡频率为5 Hz时气道黏性阻力(R5)、震荡频率为5 Hz时呼吸总阻抗(Z5)]与MEFV参数[达峰容积比(VPEF/VE)、达峰时间比(TPTEF/TE)、用力呼出50%肺活量的呼气流量(FEF50%)、用力呼出25%肺活量的呼气流量(FEF25%)、呼气峰流速(PEF)、第1秒用力呼气容积与用力肺活量的比值(FEV1/FVC)],并分析A、B组患儿IOS参数与MEFV参数的相关性。结果A组患儿IOS参数较B、C组更高,MEFV参数较B、C组更低,差异均有统计学意义(P<0.05);B组患儿IOS参数较C组更高,MEFV参数较C组更低,差异均有统计学意义(P<0.05)。Pearson分析显示,A组患儿Z5与TPTEF/TE呈负相关(r=-0.302,P<0.05),Rc、Z5与FEF25%呈负相关(r=-0.354、-0.309,P<0.05),R5、Z5与FEF50%、FEV1/FVC呈负相关(r=-0.329、-0.309、-0.306、-0.520,P<0.05),X5与各项MEFV参数呈负相关(r=-0.520、-0.390、-0.356、-0.352、-0.366、-0.556,P<0.05);B组患儿Z5与TPTEF/TE呈负相关(r=-0.302,P<0.05),Rc、Z5与FEF50%、FEF25%呈负相关(r=-0.375、-0.364、-0.343、-0.316,P<0.05),R5、Z5与FEV1/FVC呈负相关(r=-0.322、-0.413,P<0.05),X5与各项MEFV参数呈负相关(r=-0.525、-0.475、-0.329、-0.355、-0.374、-0.532,P<0.05)。结论IOS检测在小儿支气管哮喘诊疗中的应用价值显著,对拒绝接受MEFV法检测的患儿,IOS检测可快速、精准地诊断其病情,且发作期哮喘患儿诊断中X5最为敏感。

最大呼气流量-容积曲线下降支夹角在慢性阻塞性肺疾病和支气管哮喘评估中的价值

目的探讨最大呼气流量-容积(MEFV)曲线下降支夹角在慢性阻塞性肺疾病(COPD)与支气管哮喘(哮喘)评估中的价值。方法选择2008年11月至2009年12月在中山医院就诊的阻塞性通气功能障碍患者306例,其中COPD 157例,哮喘149例,测量MEFV曲线下降支夹角α,进行统计学分析。以COPD为试验组,哮喘为对照组,绘制α的ROC曲线并计算曲线下面积。结果随阻塞程度的加重,COPD患者的α变小(P<0.01),α补角的正切值TAN与FEV1.0呈明显负相关(r=-0.640,P=0.000);而哮喘患者基本不变(P>0.05),且其补角的正切值TAN与FEV1.0有较低程度的负相关(r=-0.206,P=0.012)。轻度阻塞时,COPD和哮喘患者的α相似(P=0.177)。中、重度阻塞时,COPD患者的α皆显著小于哮喘患者(皆为P=0.000)。轻度阻塞时,ROC曲线下的面积为0.431;中度阻塞时为0.846,最佳阈值135.5°,诊断COPD的敏感度81.7%,特异度74.2%,阳性预测值75.4%,阴性预测值80.7%;重度阻塞时为0.928,最佳阈值129.5°,诊断COPD的敏感度87.5%,特异度84.0%,阳性预测值91.3%,阴性预测值77.8%。结论反映MEFV曲线下降支凹陷程度的夹角α的大小可以反映COPD患者阻塞的严重程度,但仅能反映哮喘患者气道阻塞的存在,有助于进一步阐明两者的病理、病理生理特点和进行鉴别诊断。

陶瓷尘对工人小气道功能的影响

选择接触陶瓷粉尘工人339名和非接触者329名,对其小气道功能进行了测定。结果显示,无论吸烟与否,接尘工人小气道各指标实测值、实测值占预计值百分比均低于对照组,除V_(25)外均有显著差别(P<0.01),各项指标的异常率均高于对照组。提示陶瓷尘对工人的小气道功能有一定影响。

272例健康人最大呼气流量—容积曲线测定及年龄对通气功能的影响

对272例健康人进行了肺活量、最大呼气流量—容积曲线测定。以横向年龄分组的方法分析了年龄对通气功能各参数的影响。最大呼气中期流量(MMEF)与50％和25％肺活量时的最大呼气流量及其身高的比值((?)_(50)、(?)_(25)、(?)_(50)/HT、(?)_(25)/HT)高度相。认为MMEF也可作为小气道功能测定的指标。

Analysis on relationship of parameters such as R5 and MEFV with severity of chronic cough in 3 to 5 years old children by impulse oscillometry detection

Objective:The article aims to investigate the relationship of parameters such as airway vicosity resistance (R5) and maximal expiratory flow-volume curve (MEFV) with severity of chronic cough in 3 to 5 years old children by impulse oscillometry (IOS) detection when the oscillation frequency is 5Hz.Method: The article chooses eighty children with chronic cough who were diagnosed or treated in our hospital from March 2017 to March 2018 as the research group, and chooses 50 healthy children who had physical examination in our hospital as the control group. Children's asthma control test (C-ACT) is used to assess the disease severity of children. MEFV detection is carried out to the two groups of children to obtain the ratio of forced expiratory volume in one second and forced vital capacity (FEV1/FVC) and the peak expiratory flow (PEF). LsS inductance (X5) is detected by IOS when R5, the resonant frequency (Fres), and the oscillation frequency is 5Hz. The relationship of ACT score with MEFV and IOS indicators is analyzed by Pearson correlation. The receiver operating characteristic (ROC) curve is used to evaluate the diagnostic value of MEFV and IOS indicators to chronic cough. Results: The C-ACT score of the severe group is significantly lower than that of the control group (P<0.05). FEV1/FVC and PEF of the mild and severe groups are both lower than those of the control group, and FEV1/FVC and PEF of the severe group is lower than those of the mild group (P<0.05). Fres, R5 and X5 of the mild and severe groups are significantly higher than those of the control group, and Fres, R5 and X5 of the severe group are higher than the mild group (P<0.05). FEV1/FVC and PEF are positively correlated with C-ACT score (P<0.05), while Fres, R5 and X5 are negatively correlated with C-ACT score (P<0.05). FEV1/FVC and PEF respectively shows significant negative correlations with Fres, R5 and X5 (P<0.05). R5 has a self-high ROC value of 0.938, followed by Fres, which is 0.917. And the value of IOS diagnostic indicators is higher than MEFV indicators.Conclusion: FEV1 / FVC and PEF of children with chronic cough will decrease while Fres, R5 and X5 will increase, of which Fres, R5 and X5 have a higher correlation with the severity of cough symptoms, and ROC analysis results also show that R5 has the highest diagnostic value to 3~5 years old children with chronic cough.