Mixed infiltrative and obstructive disease on high-resolution CT: differential diagnosis and functional correlates in a consecutive series

Fourteen of 400 consecutive patients having high-resolution computed tomography (HRCT) with expiratory images showed findings of infiltrative lung disease on inspiratory HRCT and air trapping on expiratory CT. Diagnoses included hypersensitivity pneumonitis, sarcoidosis, atypical infection, and pulmonary edema. The extent of infiltrative abnormalities and air trapping were correlated with pulmonary function tests (PFT) in 11 patients. PFT indicated a mixed pattern in five, an obstructive pattern in three, and a restrictive pattern in three. Forced expiratory volume (FEV) in 1 second/forced vital capacity (FVC) correlated significantly with the extent of air-trapping (r = 0.60; p = 0.05). The extent of infiltrative abnormalities correlated significantly and negatively with forced vital capacity (r = -0.82, p = 0.002), FEV1 (r = -0.59, p = 0.05), total lung capacity (TLC) (r = -0.67, p = 0.05), and DLCO (r = -0.75, p = 0.02). Findings of lung infiltration on inspiratory HRCT scans and air trapping on expiratory CT correlated respectively with PFT measures of restrictive and obstructive lung disease.     

Pulmonary function test before and after operation of coronary artery by-pass surgery

Respiratory complications after successful CABG operation continuous to have on influence on the immediate recovery of a patient. It was reported that the mortality risk of the CABG patients increased, proportional to the reduction of pulmonary function tests (PFT). In the present study we aimed to investigate PFT values (vital capacity: VC, total lung capacity: TLC, residual volume: RV, functional residual capacity: FRC, force expiratory volume first second: FEV1, force mid expiratory flow: FEF25-75, duration force expiratory flow in vital capacity 25%: FEF25, duration force expiratory flow in vital capacity 50%: FEF50, duration force expiratory flow in vital capacity 75%: FEF75, peak expiratory flow: PEF, RV/TLC, FEF/FIF, FEV1/FVC) and arterial blood gases (pH, PaCO2, PaO2, SaO2) pre- and postoperatively which undergo CABG. The PFT and arterial blood gases values of 20 patients, age between 39-74 years, were measured that were undergo CABG operation before a week and three months after.The measured PFT values of 20 patients were recorded by system 2400 computerized and sensor medix 6200 and arterial blood gases analysed by radiometer ABL 300. The results were compared by the time and periods of before and after CABG operation, statistically evaluated the pearson's correlation and Student's t-test. In the results the postoperative PFT values were significantly decreased (p< 0.05, p< 0.001). But the RV, RV% and RV/TLC values were not changed significantly. In arterial blood gases values were not significantly changes. To avoid the postoperative complications we suggested that should be done the PFT and arterial blood gases measurement preoperatively.     

IL13 promoter polymorphism 1112C/T modulates the adverse effect of tobacco smoking on lung function

RATIONALE: Although the duration and amount of cigarette smoking correlate with reduction in pulmonary function, there is still variation among individual responses. IL-13 is involved in pulmonary inflammation, remodeling, and susceptibility to chronic obstructive pulmonary disease (COPD). OBJECTIVES: We investigated whether the relationships between smoking and the lung function measures FEV(1) and FEV(1)/FVC ratio are modulated by IL13 polymorphisms. METHODS: Smokers (>or=20 pack-years), aged at least 40 years old (n = 1,073), were genotyped for three single nucleotide polymorphisms (SNPs; -1112C/T [rs1800925], +2044G/A [rs20541, R130Q], and +2525G/A [rs1295685]) in the IL13 gene. Linear, quantile, and logistic regression methods were used to assess the effect of cigarette smoking (pack-years), IL13 polymorphisms, and their interaction on %predicted FEV(1) and FEV(1)/FVC ratio. Age, sex, and current smoking status were included as confounders. MEASUREMENTS AND MAIN RESULTS: The number of pack-years smoked was associated with a lower value for both %predicted FEV(1) and FEV(1)/FVC (P < 0.001).The three SNPs were not associated with lung function measures; however, there was a significant combined effect between smoking and the promoter polymorphism -1112C/T on %predicted FEV(1) (P for interaction < 0.03 for mean %predicted FEV(1) and < 0.0001 for 90th percentile %predicted FEV(1)). Every 20-pack-year increment in smoking was associated with a 2.4% reduction in mean %predicted FEV(1) in the common homozygous (CC) or heterozygous (CT) promoter genotypes, and an 8.2% reduction in mean %predicted FEV(1) in minor allele homozygotes (TT, recessive model). CONCLUSIONS: An IL13 polymorphism in the promoter region may modulate the adverse effects of cigarette smoking on pulmonary function in long-term cigarette smokers.     

AECOPD患者64层MSCT肺容积成像与肺功能测定的相关性研究

目的分析64层螺旋CT(MSCT)检测慢性阻塞性肺疾病急性加重期(AECOPD)患者肺容积指数的准确性,探讨MSCT对AECOPD患者的诊断价值,为AECOPD患者的临床诊断提供可借鉴的方法。方法选取2014年1月-2015年9月我院呼吸内科收治的AECOPD患者247例为观察组,另选取同期接受体检的健康志愿者50例为对照组,进行64层MSCT肺容积成像和常规肺功能检查(PFT),两项检查时间间隔小于3天,测定两组不同肺区的肺容积指标并与临床PFT指标进行相关性分析。结果观察组与对照组的肺功能指标存在差异,具有统计学意义(P0.05)。观察组的肺容积指标Vin、Vex、(Vin-Vex)、Vin/Vex、(VinVex)/Vin与对照组的各项肺容积指标亦存在着差异,具有统计学意义,(P0.05)。本研究中还发现,观察组MSCT肺容积指标Vex、Vex/Vin、Vin-Vex/Vin与FEV_1、FEV_1/FVC、TLC、RV/TLC之间均有相关性;Vin与FEV_1/FVC、TLC、RV/TLC之间有相关性;Vin-Vex与肺功能指标之间无相关性。结论 64排螺旋CT呼吸双相高分辨率肺容积测定指标与肺功能测定指标具有良好相关性,对诊断AECOPD有预测意义。     

Timing and driving components of the breathing strategy in children with cystic fibrosis during exercise

The aim of this study was twofold: first, to determine the breathing strategies of children with cystic fibrosis (CF) during exercise, and secondly, to see if there was a correlation with lung function parameters. We determined the tension-time index of the inspiratory muscles (T(T0.1)) during exercise in nine children with CF, who were compared with nine healthy children with a similar age distribution. T(T0.1) was determined as followed T(T0.1) = P0.1/PImax . T(I)/T(TOT), where P0.1 is mouth occlusion pressure, PImax is maximal inspiratory pressure, and T(I)/T(TOT) is the duty cycle. CF children showed a significant decrease of their forced expiratory volume in 1 sec (FEV1), forced vital capacity (FCV), and FEV1/FVC, whereas the residual volume to total lung capacity ratio (RV/TLC) ratio and functional residual capacity (FRC) were significantly increased (P < 0.001). Children with CF showed mild malnutrition assessed by actual weight expressed by percentage of ideal weight for height, age, and gender (weight/height ratio; 82.3 +/- 3.6%). Children with CF showed a significant reduction in their PImax (69.3 +/- 4.2 vs. 93.8 +/- 7 cmH2O). We found a negative linear correlation between PImax and weight/height only in children with CF (r = 0.9, P < 0.001). During exercise, P(0.1), P0.1/PImax, and T(T0.1) were significantly higher, for a same percent maximal oxygen uptake in children with CF. On the contrary, T(I)/T(TOT) ratio was significantly lower in children with CF compared with healthy children. At maximal exercise, children with CF showed a T(T0.1) = 0.16 vs. 0.14 in healthy children (P < 0.001). We observed at maximal exercise that P0.1/PImax increased as FEV1/FVC decreased (r = -0.90, P < 0.001), and increased as RV/TLC increased (r = 0.92, P < 0.001) only in children with CF. Inversely, T(I)/T(TOT) decreased as FEV1/FVC decreased (r = 0.89, P < 0.001), and T(I)/T(TOT) decreased as RV/TLC increased (r = -0.94, P < 0.001). These results suggest that children with CF adopted a breathing strategy during exercise in limiting the increase of the duty cycle. Two determinants of this strategy were degrees of airway obstruction and hyperinflation.     

Paired inspiratory/expiratory volumetric thin-slice CT scan for emphysema analysis: comparison of different quantitative evaluations and pulmonary function test

PURPOSES: The aim of the study was to use three-dimensional high-resolution CT scan data sets in inspiration and expiration for the quantitative evaluation of emphysema. Using an advanced dedicated semiautomatic analysis tool, the functional inspiratory/expiratory shifts of emphysema volume and clusters were quantified. The pulmonary function test (PFT) served as the clinical "gold standard." MATERIALS AND METHODS: Thirty-one patients (9 women and 22 men; mean [+/- SD] age, 60 +/- 8 years) who had severe emphysema due to COPD (Global Initiative for Chronic Obstructive Lung Disease [GOLD] class III and IV) were included in the study. All patients underwent paired inspiratory/expiratory multidetector CT scans (slice thickness, 1/0.8 mm) and pulmonary function tests (PFTs). CT scan data were analyzed with self-written emphysema detection solftware. It provides lung volume (LV), emphysema volume (EV), emphysema index (EI), and four clusters of emphysema with different volumes (from 2, 8, 65, and 120 mm(3)). These results were correlated with total lung capacity (TLC), intrathoracic gas volume (ITGV), and residual volume (RV) derived from PFT results. RESULTS: Inspiratory LV correlated with TLC (r = 0.9), expiratory LV with ITGV (r = 0.87), and RV (r = 0.83). Expiratory EV correlated better with ITGV (r = 0.88) and RV (r = 0.93) than with inspiratory EV (r = 0.83 and 0.88, respectively). The mean inspiratory EI was 54 +/- 13%, and it decreased to 43 +/- 15% in expiration. However, the individuals showed a broad spectrum of changes of EI (mean, 11%; range, 1 to 28%), and no differences in inspiratory/expiratory EI and changes in EI or LV were found between GOLD III and GOLD IV patients. In expiration, there was a change from the large emphysema cluster (-37%) to the intermediate cluster (+15%) and small cluster (+13% and +11%, respectively). The change of volume of the large emphysema cluster after expiration correlated well with the changes in LV (r = 0.9), EV (r = 0.99), EI (r = 0.85), and MLD (r = 0.76). CONCLUSION: Emphysema volumes measured from expiratory MDCT scans better reflect PFT abnormalities in patients with severe emphysema than those from inspiratory scans. Volumetric cluster analysis provided deeper insights into the local hyperinflation and expiratory obstruction of large emphysematous clusters.     

Lung dysfunction of chronic smokers with no signs of COPD

Cigarette smoking causes airflow limitation with lung hyperinflation being the primary causes of COPD. Fifty chronic smokers (CSs) with no signs of GOLD-adjusted COPD with smoking habit at least ≥10 pack-years (p/yrs) were divided into CS-mild (n = 24) with smoking history from ≥10 to ≤20 p/yrs and CS-heavy groups (n = 26) with smoking history ≥21 p/yrs. Spirometry, plethysmography and diffusing capacity were measured and lung computed tomography (CT) was performed. Residual volume (RV) (L) and RV/TLC (total lung capacity) ratio were significantly increased in CS-heavy when compared to CS-mild (p = 0.001, p = 0.03). A significant reduction of forced expiratory volume in 1 second/forced vital capacity (FEV(1)/FVC) ratio and airway specific conductance was shown in CS-heavy (p = 0.02, p = 0.03). Lung emphysema signs at CTs were revealed in 17 CSs and ten of them had declined diffusing capacity below 70% of predicted. The percentage of emphysematous lesions inversely and significantly correlated with measured diffusing capacity (p = 0.0009, r = --0.72). Study groups' smoking intensity inversely correlated the declined airway specific conductance (p = 0.004, r = --0.39) and increase of the RV (L) (p = 0.0004, r = 0.46). Multiple regression analysis determined that smoking intensity regardless of the subjects' age was significant factor for decline of airway specific conductance and increase of RV (L). Here we conclude that lung function deviation and lung structural changes are present in CSs before the clinical signs of airway obstruction reveal. Body plethysmography and diffusing capacity measurement with routine spirometry can provide valuable information for detection of changes reflecting to the early onset of COPD in CSs.     

Expiratory and inspiratory chest computed tomography and pulmonary function tests in cigarette smokers.

This study evaluated small airway dysfunction and emphysematous destruction of lung parenchyma in cigarette smokers, using chest expiratory high-resolution computed tomography (HRCT) and pulmonary function tests (PFT). The degree of emphysematous destruction was classified by visual scoring (VS) and the average HRCT number at full expiration/full inspiration (E/I ratio) calculated in 63 male smokers and 10 male nonsmokers (group A). The Brinkman smoking index (BI), defined as cigarettes x day(-1) x yrs, was estimated. Sixty-three smokers were divided into three groups by PFT: group B1 (n=7), with normal PFT; group B2 (n=21), with diffusing capacity of the lung for carbon monoxide (DL,CO) > or = 80% predicted, forced expiratory volume in one second (FEV1) < 80% pred and/or residual volume (RV) > 120% pred; and group B3 (n=35), with DL,CO < 80% pred, FEV1 < 80% pred and/or RV > 120% pred. Heavy smokers (BI > or = 600) (n=48) showed a significant increase in emphysema by both VS and E/I. E/I was significantly elevated in both group B2 (mean+/-SD 0.95+/-0.05) and B3 (0.96+/-0.06) compared with group B1 (0.89+/-0.03). VS could not differentiate group B2 (3.9+/-5.0) from B1 (1.1+/-1.6). These findings suggest that the expiration/inspiration ratio reflects hyperinflation and airway obstruction, regardless of the functional characteristics of emphysema, in cigarette smokers.     

50例健康老年人肺功能10年随访观察

目的为临床和基础研究提供健康老年人肺功能各项指标随增龄改变的参考资料。方法采用日本Ｃｈｅｓｔａｃ６５型肺功能检查仪,按常规方法进行肺功能检查。结果用力肺活量（ＦＶＣ）每年下降００３２Ｌ,第１秒用力呼气量（ＦＥＶ１）每年下降００３Ｌ,ＦＥＶ１占用力肺活量比值（ＦＥＶ１％）每年下降０１５１％,呼气流量峰值（ＰＥＦＲ）每年下降０１１８Ｌ／ｓ,最大呼气中段流量（ＭＭＥＦ）每年下降００４Ｌ／ｓ,最大通气量（ＭＶＶ）每年下降０８７６Ｌ,肺活量（ＶＣ）每年下降００４Ｌ,残气容积（ＲＶ）每年升高００３３Ｌ,功能残气量（ＦＲＣ）每年升高００３３Ｌ,残气容积／肺总量（ＲＶ／ＴＬＣ）每年升高０５９６％。戒烟组的健康老年人ＶＣ、ＦＶＣ、ＦＥＶ１、ＲＶ、ＲＶ／ＴＬＣ与从不吸烟健康老年人比较差异有显著性;不同年龄组的健康老年人肺功能下降不明显。结论肺功能各项指标随增龄而改变,健康老年人各年龄组肺功能改变不明显,吸烟对健康老年人肺功能改变有一定影响。     

Preoperative predictors of prolonged postoperative mechanical ventilation in children following scoliosis repair

Scoliosis is associated with progressive restrictive lung disease and an increased risk of pulmonary complications following surgical correction. Identification of higher risks for prolonged postoperative mechanical ventilation (MV) improves postoperative care. Our objective was to determine if preoperative pulmonary function tests (PFT) predict prolonged postoperative MV (defined as MV >or=3 days). We correlated preoperative PFT (forced expired volume in 1 sec, FEV1; vital capacity, VC; inspiratory capacity, IC; maximal inspiratory pressure, MIP; total lung capacity, TLC; and residual volume, RV) and postoperative MV days in 125 patients who had scoliosis surgery (aged 13.7 +/- 3.0 (SD) years) from January 1990-July 2001. We had 71 male and 54 female patients. Scoliosis types were 13 congenital, 27 idiopathic, 57 neuromuscular, 23 syndrome/tumor, and 5 kyphoscoliosis. Forty patients (32%) had postoperative MV >or=3 days. Independent factors likely requiring postoperative MV >or=3 days were neuromuscular scoliosis (P < 0.001) and FEV1 <40% predicted. Independent factors most likely were: neuromuscular scoliosis with preoperative FEV1 <40% predicted (P < 0.01). Independent factors most unlikely were: idiopathic scoliosis (P < 0.002). VC <60% predicted, IC <30 ml/kg, TLC <60% predicted, and MIP <60 cm H2O correlated with postoperative MV >or=3 days (P < 0.05). We found no association between RV and postoperative MV. FEV1 <40% predicted, VC <60% predicted, IC <30 ml/kg, TLC <60% predicted, MIP <60 cm H2O, and neuromuscular disease each correlated with prolonged postoperative MV. Neuromuscular disease or a preoperative FEV(1) <40% predicted were more likely, and older children with neuromuscular disease and FEV1 <40% predicted were most likely to require prolonged postoperative MV (P < 0.01). Clearly FEV1, and possibly VC, IC, TLC, and MIP, may increase accuracy in predicting the need for prolonged postoperative MV.     

Lung CT densitometry in systemic sclerosis: correlation with lung function, exercise testing, and quality of life

BACKGROUND: To ascertain if analysis of lung density histograms in thin-section CT was more reproducible than visual assessment of lung changes in systemic sclerosis (SSc), and if such density histogram parameters as mean lung attenuation (MLA), skewness, and kurtosis could more closely reflect pulmonary function as well as exercise and quality of life impairment. METHODS: The intraoperator and interoperator reproducibility of visual and densitometric lung CT analysis in 48 SSc patients examined with CT were evaluated by means of weighted kappa statistics. Univariate and multivariate regression analyses were applied to evaluate the relationship of visual and densitometric CT measurements with functional parameters including functional residual capacity (FRC), FVC, FEV(1), diffusion capacity of the lung for carbon monoxide (Dlco), 6-min walking testing (6MWT), and health-related quality of life questionnaire (QLQ) parameters. RESULTS: The intraoperator and interoperator reproducibility of MLA (intraobserver weighted kappa = 0.97; interobserver weighted kappa = 0.96), skewness (intraobserver weighted kappa = 0.89; interobserver weighted kappa = 0.88), and kurtosis (intraobserver weighted kappa = 0.89; interobserver weighted kappa = 0.88) were higher than those of visual assessment (intraobserver weighted kappa = 0.71; interobserver weighted kappa = 0.69). In univariate analysis, only densitometric measurements were correlated with some exercise and QLQ parameters. In multivariate analysis, MLA (square regression coefficient corrected [R(2)c] = 0.70), skewness (R(2)c = 0.78), and kurtosis (R(2)c = 0.77) were predicted by FRC, FVC, Dlco, 6MWT, and QLQ parameters, while visual assessment was associated only with FRC and FVC (R(2)c = 0.40). CONCLUSIONS: In SSc, densitometric analysis is more reproducible than visual assessment of lung changes in thin-section CT and more closely correlated to pulmonary function testing, 6MWT, and QLQ. Density histogram parameters may be useful for cross-sectional and longitudinal studies of lung involvement in SSc.     

肺泡蛋白沉着症患者的肺功能与胸部分辨率CT的相关性

目的 探讨PAP患者的肺功能与高分辨率CT定量测量指标之间的相关性.方法 对2004至2007年在广州医学院第一附属医院呼吸疾病研究所住院的17例PAP患者(男10例,女7例,年龄15～51岁)进行肺通气及弥散功能检查和高分辨率CT检查,分析肺功能指标与高分辨率CT定量指标之间的相关性.比较其中6例行全肺肺泡灌洗治疗前、后的肺功能和高分辨率CT定量指标的变化.采用SPSS 13.0软件进行数据处理,结果 以x±s表示.结果 PAP患者的肺功能检查结果 以限制性通气功能障碍和弥散功能下降为主,弥散功能下降更为显著,DLCO占预计值%为(46±22)%,异常率为94.1%.肺功能检查结果 与高分辨率CT定量检查结果 之间存在一定的相关性,其中平均肺密度与FVC、肺重量与FEV1、肺含气容积比与呼气峰流量、DL.CO、DLCO与肺泡通气量比值(DLCO/VA)等指标的改变差异有统计学意义,(r值分别为-0.469、-0.482、0.511、0.659、0.692,均P<0.05),在所有指标中以肺含气容积比与DLCO/VA关系最为密切.6例肺泡灌洗术治疗的患者术后肺功能和高分辨率CT定量测量指标有所改善.结论 PAP的肺功能和胸部高分辨率CT改变之间存在相关性.2项检查同时进行可作为PAP患者随访的重要参考指标.     

Tiotropium and simplified detection of dynamic hyperinflation

STUDY OBJECTIVE: To detect dynamic hyperinflation (DH) by evaluating reduction in inspiratory capacity (IC) during metronome-paced hyperventilation (MPH) in patients with moderate-to-severe COPD, studied before and after treatment with tiotropium. METHODS: IC and FEV(1) were measured before and immediately after MPH at two times resting the respiratory rate for 20 s in 60 COPD patients (28 men; mean age, 66 +/- 10 years [+/- SD]) before and after 30 days of treatment with tiotropium bromide, 18 mug. Patients were encouraged to maintain a constant tidal volume during MPH. RESULTS: At baseline, mean FEV(1) was 1.5 +/- 0.1 L (+/- SE) [57 +/- 1.6% of predicted], mean FVC was 2.6 +/- 0.1L (77 +/- 1.8% of predicted), and mean FEV(1)/FVC was 56 +/- 1%. After 180 mug of aerosolized albuterol sulfate, mean FEV(1) was 1.7 +/- 0.1 L (63 +/- 1.5% of predicted) [p < 0.001] and mean FEV(1)/FVC was 58 +/- 1%. Compared to baseline, after 30 days and 1.5 h after tiotropium there was an increase in IC of 0.18 +/- 0.04L (p < 0.0001); FEV(1) of 0.13 +/- 0.03 L (5.6 +/- 0.8% of predicted; p = 0.0002); FVC of 0.22 +/- 0.05 L (6.5 +/- 1.3% of predicted; p < 0.001); and decrease in end-expiratory lung volume (EELV)/total lung capacity (TLC) of - 3.1 +/- 0.6% (p = 0.0001); a decrease in end-inspiratory lung volume (EILV)/TLC of - 2.9 +/- 1.3% (p = 0.03); and no change in TLC (- 0.06 +/- 0.05 L). Results following MPH-induced DH at baseline and after 30 days of tiotropium were similar, with decreases in IC (- 0.35 +/- 0.03 L; p < 0.001); FEV(1) (- 0.05 +/- 0.04 L; p = 0.2); and FVC (- 0.22 +/- 0.03 L; p < 0.0001); no change in TLC; and increases in EELV/TLC (11.8 +/- 1.0% of predicted; p < 0.0001) and EILV/TLC (4.0 +/- 1.3% of predicted, p < 0.003). CONCLUSION: In patients with moderate-to-severe COPD, tiotropium did not reduce MPH-induced DH and reduction in IC, compared to baseline. However, because tiotropium induced bronchodilation and increased baseline IC, lower operational lung volumes may blunt the effect of MPH-induced DH. The noninvasive simplicity of MPH-induced DH provides a clinically useful screening surrogate to monitor changes in IC following treatment with tiotropium.     

Effect and duration of lung volume reduction surgery: mid-term results of the Brompton trial

Although many studies have reported improvement in lung function following LVRS, the magnitude of improvement and subsequent decline has not been evaluated against medical therapy after the second year. METHODS: Existing pulmonary function records were collapsed for ech participant since randomisation from Brompton LVRS trial cohort. Longitudinal data analysis was used to profile th history of medically treated patients and the effect of LVRS. RESULTS: Pulmonary function results were collated from survivors over a median of 25 (17 to 39) months. The estimated immediate increase in mean FEV1, following surgery was +0.2591 (0.179, 0.339), with a rate of change of -0.0051 (-0.009, -0.001) per month compared to medical therapy (p < 0.001). The changes in the secondary outcome measures (LVRS compared to medical therapy) were an increase in FVC (p = 0.004), decrease in RV (p < 0.001) and TLC (p < 0.001), with differences that were maintained over time. The initial reduction in RV/TLC ration was sustained (p < 0.001), but the estimated initial increase in peak flow was accompanied by a gradual decline that was not statistically significant (p = 0.062). KCOc showed no immediate change, but there was a gradual sustained increase with time (p = 0.009). Mean oxygen saturations improved and continued to do so compared to patients on medical therapy (p = 0.001). CONCLUSIONS: The immediate increase in FEV1 is not sustained, although the mechanical improvements of LVRS on increasing FVC, reducing both the RV and RV/TLC ratio, appear to be maintained. The important benefits of LVRS may be the gradual and sustained increase in transfer factor accompanied by improved oxygen saturations.     

Computed tomography-quantified emphysema distribution is associated with lung function decline

Emphysema distribution is associated with chronic obstructive pulmonary disease. It is, however, unknown whether computed tomography (CT)-quantified emphysema distribution (upper/lower lobe) is associated with lung function decline in heavy (former) smokers. 587 male participants underwent lung CT and pulmonary function testing at baseline and after a median (interquartile range) follow-up of 2.9 (2.8-3.0) yrs. The lungs were automatically segmented based on anatomically defined lung lobes. Severity of emphysema was automatically quantified per anatomical lung lobe and was expressed as the 15th percentile (Hounsfield unit point below which 15% of the low-attenuation voxels are distributed (Perc15)). The CT-quantified emphysema distribution was based on principal component analysis. Linear mixed models were used to assess the association of emphysema distribution with forced expiratory volume in 1 s (FEV(1))/forced vital capacity (FVC), FEV(1) and FVC decline. Mean±sd age was 60.2±5.4 yrs, mean baseline FEV(1)/FVC was 71.6±9.0% and overall mean Perc15 was -908.5±20.9 HU. Participants with upper lobe-predominant CT-quantified emphysema had a lower FEV(1)/FVC, FEV(1) and FVC after follow-up compared with participants with lower lobe-predominant CT-quantified emphysema (p=0.001), independent of the total extent of CT-quantified emphysema. Heavy (former) smokers with upper lobe-predominant CT-quantified emphysema have a more rapid decrease in lung function than those with lower lobe-predominant CT-quantified emphysema.     

A normal FEV1/VC ratio does not exclude airway obstruction

BACKGROUND: A decreased forced expiratory volume in 1 s/vital capacity (FEV(1)/VC) ratio is the hallmark of the definition of airway obstruction. We recently suggested that a lung function pattern, we called small airways syndrome (SAOS), has a normal FEV(1)/VC and total lung capacity (TLC) and reflects obstruction of small airways. OBJECTIVES: To substantiate our hypothesis we measured and compared lung function tests including maximal expiratory flow rates (MEFR), sensitive indicators of airway obstruction, in SAOS subjects and in matched controls. METHODS: We selected 12 subjects with the pattern of SAOS, but without chronic lung or heart disease (average age: 40.7 +/- 7.8 years) and 36 age-matched subjects with normal lung function (42.8 +/- 6.3 years). We measured static and dynamic lung volumes, MEFR and lung diffusing capacity (DL(CO)). RESULTS: SAOS subjects were heavier smokers (p < 0.05) and body mass index was less than in control subjects (p < 0.01). Both FEV(1)/VC ratio and TLC were comparable in the two groups. However, FEV(1), VC, DL(CO), and MEFR were lower and residual volume (RV) and RV/TLC ratio were higher (p < 0.05) in the SAOS group than in the control one. Furthermore, the MEFR curve of the SAOS group was displaced to the left without any change in slope, suggesting premature airway closure. CONCLUSION: Our results suggest that a normal FEV(1)/VC ratio does not exclude airway obstruction. A decrease of FEV(1), provided TLC is normal, reflects small airway obstruction.     

Response of lung volumes to inhaled salbutamol in a large population of patients with severe hyperinflation

OBJECTIVES: Current criteria use FEV(1) to assess bronchodilator responsiveness, despite its insensitivity and inability to predict improvement in symptoms or exercise tolerance. Response in lung volumes remains largely unexplored even though volume parameters, such as inspiratory capacity (IC), closely correlate with functional improvements. Therefore, we assessed the response of lung volumes (i.e., by IC, total lung capacity [TLC], functional residual capacity [FRC], residual volume [RV], and FVC) to salbutamol and the relationship of these changes to improvements in the spirometry in these patients. DESIGN: A retrospective review of data extracted from a large database of patients who were undergoing spirometry and static lung volume measurements before and after the administration of 200 microg salbutamol. PATIENTS: Patients with an FEV(1)/FVC ratio of < 85% of predicted values were defined as being severely hyperinflated (SH) if TLC was > 133% of predicted and as being moderately hyperinflated (MH) if TLC was 115 to 133% of predicted. RESULTS: Two hundred eighty-one SH patients and 676 MH patients were identified. Salbutamol significantly reduced the mean (+/- SEM) TLC (SH patients, 222 +/- 23 mL; MH patients, 150 +/- 10 mL; p < 0.001), FRC (SH patients, 442 +/- 26 mL; MH patients, 260 +/- 39 mL; p < 0.001), and RV (SH patients, 510 +/- 28 mL; MH patients, 300 +/- 14 mL; p < 0.001) and increased both the IC (SH patients, 220 +/- 15 mL; MH patients, 110 +/- 11 mL; p < 0.001) and FVC (SH patients, 336 +/- 21 mL; MH patients, 204 +/- 13 mL; p < 0.001). FEV(1) improved in a minority of patients (SH patients, 33%; MH patients, 26%), but if lung volume measurements are also considered, the overall bronchodilator response may improve to up to 76% of the SH group and up to 62% of the MH group. Changes in volumes correlated poorly with changes in maximal airflows. CONCLUSIONS: Bronchodilators reduce hyperinflation. Measurements of lung volumes before and after bronchodilators add sensitivity when examining for bronchodilator responsiveness.     

戒烟10年以上的健康老年人肺功能10年随访研究

目的　观察健康老年人戒烟１０ 年后肺功能的１０ 年变化。方法　５１ 名戒烟１０ 年以上的健康老年人为研究对象，并挑选条件相同的从不吸烟健康老年人１２ 名作为随访对照，肺功能检查按常规方法进行。结果　戒烟１０ 年后健康老年人在随访的１０ 年中肺功能与从不吸烟健康老年人肺功能相比，肺活量（ＶＣ）、用力肺活量（ＦＶＣ） 、一秒钟用力呼气容积（ＦＥＶ１） 年下降值差异有显著性（Ｐ＜０－０１）；呼气峰流速（ＰＥＦ）年下降值差异有显著性（Ｐ＜０－０５）；残气量（ＲＶ）、残气量／肺总量（ＲＶ／ＴＬＣ）的年增加值差异有显著性（ Ｐ＜０－０１） 。一秒钟用力呼气容积与用力肺活量比值（ＦＥＶ１／ＦＶＣ） 、最大通气量（ＭＶＶ） 、最大呼气中期流量（ＭＭＥＦ）、功能残气量（ＦＲＣ）、肺总量（ＴＬＣ） 也有一定的改变，但变化值未达到统计学意义。结论　通过随访研究发现即使戒烟后曾吸烟对肺功能仍然存在一定影响，可能与研究对象吸烟时间长，吸烟量大所形成某些不可逆病理变化有关，并建议吸烟者应尽早戒烟。     

Respiratory muscle force and ventilatory function in adolescents

In 94 girls and 90 boys, aged 12.5-20.3 yr, the relationship of respiratory pressures or forces with lung volumes and ventilatory flows was studied. There was great variability in respiratory muscle performance, which helps to explain differences in lung volumes between individuals. Respiratory muscle force increases almost proportionally with thoracic dimensions, so that inspiratory and expiratory pressures generated at the level of residual volume (RV), functional residual capacity (FRC) and total lung capacity (TLC) are approximately constant with age. In the oldest boys there is evidence that the continued increase in lung volumes when they stop growing is due to a 'muscularity effect'. Boys generate larger pressures than girls at all lung volumes. Thus boys attain a larger TLC, and in spite of narrower airways, the same peak expiratory flow and a larger FIV1/FVC ratio than girls. Effort independent flows (FEV1 and MMEF), however, are larger in girls.