Improved quality of life after lung volume reduction surgery.

Lung volume reduction surgery (LVRS) improves dyspnoea, pulmonary function, and physical performance in patients with severe pulmonary emphysema. This study investigated the impact of LVRS on health-related quality of life (HRQL) over a 2-yr period following surgery. Thirty-nine consecutive patients were prospectively assessed before LVRS, and followed over 24 months postoperatively. The assessments included pulmonary function, dyspnoea (Medical Research Council (MRC) dyspnoea score), 6-min walking distance (6MWD) and HRQL using the Short Form 36-item questionnaire (SF-36). Several domains of SF-36 improved considerably over 2 yrs after surgery: Physical Functioning: 39 +/- 4 (mean +/- SEM) versus 16 +/- 2 (p<0.01); Vitality: 51 +/- 3 versus 32 +/- 3 (p<0.01); Social Functioning: 72 +/- 4 versus 51 +/- 5 (p<0.01). Also, improvements in pulmonary function (forced expiratory volume in one second (FEV1): 27 +/- 1% predicted, residual volume (RV)/total lung capacity (TLC): 0.65 +/- 0.01), 6 MWD (274 +/- 16 m) and dyspnoea (MRC: 3.9 +/- 01) were sustained for up to 2 yrs after LVRS (FEV1 36 +/- 2% pred, RV/TLC: 0.58 +/- 0.02; 6 MWD: 342 +/- 19 m; MRC: 2.0 +/- 0.2; p<0.05). In patients with severe emphysema, lung volume reduction surgery had positive effects on health-related quality of life and pulmonary function over 2 yrs.     

Lung volume reduction surgery versus conservative treatment in severe emphysema.

Lung volume reduction surgery (LVRS) has been proposed for patients with severe emphysema to improve dyspnoea and pulmonary function. It is unknown, however, whether prognosis and pulmonary function in these patients can be improved compared to conservative treatment. The effect of LVRS and conservative therapy were compared prospectively in 57 patients with emphysema, who fulfilled the standard criteria for LVRS. The patients were divided into two groups according to their own decision. Patients in group 1 (n=29, eight females, mean+/-SEM 58.8+/-1.7 yrs, forced expiratory volume in one second (FEV1) 27.6+/-1.3% of the predicted value) underwent LVRS. Patients in group 2 (n=28, five females, 58.5+/-1.8 yrs, FEV1 30.8+/-1.4% pred) preferred to postpone LVRS. There were no significant differences in lung function between the two groups at baseline; however, there was a tendency towards better functional status in the control group. The control group had a better modified Medical Research Council (MMRC) dyspnea score (3.1+/-0.15 versus 3.5+/-0.1, p<0.04). Model-based comparisons were used to estimate the differences between the two groups over 18 months. Significant improvements were observed in the LVRS group compared to the control group in FEV1, total lung capacity (TLC), Residual volume (RV), MMRC dyspnea score and 6-min walking distance on all follow up visits. The estimated difference in FEV1 was 33% (95% confidence interval 13-58%; p>0.0001), in TLC 12.9% (7.9-18.8%; p>0.0001), in RV 60.9% 32.6-89.2%; p>0.0001), in 6-min walking distance 230 m (138-322 m; p<0.002) and in MMRC dyspnoea score 1.17 (0.79-1.55; p<0.0001). In conclusion, lung volume reduction surgery is more effective than conservative treatment for the improvement of dyspnoea, lung function and exercise capacity in selected patients with severe emphysema.     

Lung density and lung mass in emphysema.

Mean lung density (dm) and radiologic (VLx) lung volume can be calculated using CT scan data. As many emphysematous patients are overdistended, the analysis of dm alone could be meaningless. However, lung mass (m) can be calculated as the product of dm and VLx. Twenty-four patients suspected of mild or severe emphysema as judged by roentgenographic and physiologic examinations as well as 16 healthy subjects were included in the protocol. They all underwent both a CT scan of the whole lung and functional tests from which the following were derived: airway resistance, forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), total lung capacity (TLC), CO transfer capacity, quasi-static compliance at functional residual capacity (FRC), and blood gases. All CT scans were performed at the FRC of each patient. The dm was lower in emphysema patients than in healthy subjects, as m was greater in patients than in healthy subjects; 1,303 +/- 398 g and 997 +/- 133 g, respectively. Although dm values were significantly correlated to FEV1, FEV1/FVC, and TLC, m values were not correlated to any of these functional indices. Unexpectedly, these results show that most patients (22/24) with emphysema have a normal or increased lung mass. Normal or above normal m values might be due to oversecretion in some patients. Nevertheless, the synthesis of new tissue due to chronic inflammation is the most likely explanation that could account for this finding.     

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。     

Physiological changes during symptom recovery from moderate exacerbations of COPD.

Acute exacerbations of chronic obstructive disease (AECOPD) are characterised by worsening dyspnoea that is variably prolonged. In this study, physiological changes during moderate AECOPD were examined and the factors associated with dyspnoea resolution over time were determined. In total, 20 patients experiencing an AECOPD were evaluated within 72 h of initial worsening of symptoms (day 0) with pulmonary function testing, metabolic testing and symptom assessment using the dyspnoea domain of the Chronic Respiratory Disease Questionnaire (CRQ). Treatment was optimised and testing was repeated after 7, 14, 30 and 60 days. At day 0, patients were very short of breath (CRQ-dyspnoea mean+/-SEM 2.4+/-0.3) and showed significant airflow obstruction (forced expiratory volume in one second (FEV1) 41+/-3% predicted) and lung hyperinflation (forced residual capacity (FRC) 164+/-7% pred). By day 60 CRQ-dyspnoea improved to 4.6+/-0.5 (some shortness of breath); FRC and residual volume decreased by 5 and 11%, respectively; inspiratory capacity (IC) and slow vital capacity increased by 18 and 17%, respectively; and FEV1 increased by 18% with no change in FEV1/FVC. Total lung capacity did not change during AECOPD, and thus, changes in IC reliably reflected changes in end-expiratory lung volume. In conclusion, moderate acute exacerbation of chronic obstructive pulmonary disease is characterised by worsening airflow obstruction and lung hyperinflation. Improvement of dyspnoea following acute exacerbations of chronic obstructive pulmonary disease was associated with reduction in lung hyperinflation and consequent increase in expiratory flow rates.     

Lung function after bilateral lower lobe lung volume reduction surgery for alpha1-antitrypsin emphysema.

This study explores the mechanism(s) of airflow limitation following lung volume reduction surgery (LVRS) in patients with emphysema due to homozygous alpha1-antitrypsin (AT) deficiency. Bilateral targeted lower lobe stapled LVRS using video thoracoscopy was performed in six patients (five males) aged 61+/-9 yrs (mean+/-SD) with alpha1-AT emphysema. Two patients received only a 6-month follow-up. However, four patients, at 22, 24, 27 and 36 months post-LVRS, noted relief from dyspnoea and increased walk tolerance. At 27+/-6 months (mean+/-SD) post-LVRS, their forced expiratory volume in one second improved only from 30+/-2% of the predicted value (mean+/-SEM) before surgery to 33+/-1% pred after surgery. Yet, total lung capacity (TLC) decreased from 151+/-13 to 127+/-10% pred; diffusing capacity increased from 35+/-9 to 59+/-9% pred; and vital capacity increased from 68+/-10 to 88+/-5% pred. In three patients, static lung elastic recoil at TLC increased from 1.1+/-0.15 to 1.2+/-0.10 kPa. Using flow/pressure curves, the mechanism for expiratory airflow limitation pre-LVRS and the improvement noted post-LVRS could be primarily accounted for by the initial loss and subsequent increase in lung elastic recoil. Bilateral lung volume reduction surgery provides modest physiologic improvement for 2-3 yrs in patients with alpha1-antitrypsin emphysema due to increases in lung elastic recoil.     

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.     

肺纤维化合并肺气肿患者的肺功能特征

目的 了解肺纤维化合并肺气肿（combined pulmonary fibrosis and emphysema,CPFE）患者肺功能特点,及是否能通过肺功能将CPFE、单纯肺气肿、未合并肺气肿的特发性肺纤维化（idiopathic pulmonary fibrosis,IPF）进行区分.方法 回顾性分析了48例CPFE患者利用肺量计及脉冲振荡法测量的肺功能参数,并与单纯肺气肿患者（50例）、未合并肺气肿的IPF患者（46例）的肺功能进行了比较.结果 肺量计参数显示：CPFE组肺总量（TLC）％ pred正常[（86.9±17.8）％],而未合并肺气肿的IPF组TLC％ pred明显降低[（70.4±17.0）％],CPFE组的FEV1/FVC大致正常[（72.0±9.4）％],而单纯肺气肿组明显降低[（56.5±14.4）％],CPFE组、单纯肺气肿组及未合并肺气肿的IPF组的弥散功能均降低,分别为（57.2±17.3）％、（62.8±25.7）％、（66.9±21.5）％.脉冲振荡法测量的参数显示：CPFE组与未合并肺气肿的IPF组总气道阻力（R5）正常,而单纯肺气肿组明显增高[（161.3±69.0）％],虽然CPFE组、单纯肺气肿组及未合并肺气肿的IPF组外周气道阻力（R5-R20）均增加,但单纯肺气肿组较CPFE组和未合并肺气肿的IPF组增加更为明显（P=0.006,P=0.013）,三组X5轻度减低,单纯肺气肿组较CPFE组和IPF组减低更为明显（P=0.004,P=0.047）.相关分析显示：CPFE组、单纯肺气肿组R5-R20和RV/TLC呈正相关（r=0.44,P=0.01;r=0.66,P=0.01）;CPFE组、单纯肺气肿组K与RV/TLC呈负相关（r=-0.51,P=0.01; r=-0.66,P=0.01）,未合并肺气肿的IPF组TLC％ pred与R5-R20和X5有相关性（r=-0.50,P=0.01; r=0.6,P=0.01）.结论 CPFE的肺功能特点为肺容积正常,通气功能正常,弥散功能明显降低,总气道阻力及中心气道阻力正常,周边气道阻力增加和弹性阻力增高,肺的顺应性降低.     

Adult-type pulmonary function tests in infants without respiratory disease

A new method that permits the measurement of adult-type maximal expiratory flow-volume curves and fractional lung volumes in sedated infants was recently described. The purpose of this study was to define the normal range for these new measures of pulmonary function in infants and young children. Measurements of forced expiratory flows and fractional lung volume were made on 35 occasions in 22 children (ages 3-120 weeks) without respiratory disease. Maximal expiratory flow-volume curves were measured by the raised lung volume, thoracoabdominal compression technique. Functional residual capacity (FRC) was measured plethysmographically. Measurements of total lung capacity (TLC), residual volume (RV), FRC, forced vital capacity (FVC), and forced expiratory flows at 25, 50, 75, 85, and between 25% and 75% of expired FVC (FEF(25), FEF(50), FEF(75), FEF(85), and FEF(25-75), respectively) all increased in relation to infant length (P<0.001). RV/TLC, FRC/TLC, and FEF(25-75)/FVC declined in relation to increasing length (P<0.001). The forced expiratory flow and fractional lung volume measurements using this method were similar to previously reported estimates using other methods. These estimates represent a reasonable reference standard for infants and young children with respiratory problems.     

Lung volumes measured by the forced rebreathing technique in children with airways obstruction.

Forced rebreathings may recruit trapped gas into the mixing process. Therefore, we assessed the validity and reproducibility of measurements of residual volume (RVN2) by forced rebreathing in a closed circuit using N2 as indicator gas (N2FR) in children with airways obstruction. Validity was studied from measurements of RV obtained by N2FR, by helium dilution during resting ventilation, and by body plethysmograph at low panting frequency in young patients (8-18 yrs, 13 with asthma, forced expiratory volume in one second (FEV1) 93.0 +/- 22.8% pred; 12 with cystic fibrosis (CF), FEV1 80.4 +/- 16.4% pred). Reproducibility of RVN2 was assessed from duplicate measurements in 73 patients with asthma before and after bronchodilation (FEV1 81.4 +/- 13.7 and 99.6 +/- 11.5% pred, respectively), and in nine patients with CF; the total lung capacity (TLC) was unaffected by bronchodilation; 3,797 +/- 830 ml and 3,807 +/- 843 ml, respectively. Gas dilution methods gave comparable results in all subjects but gave lower values than plethysmography in patients with cystic fibrosis. Reproducibility was satisfactory, median differences between duplicate measurements of RVN2 and TLCN2 varying between 13 and 46 ml, respectively. We conclude that N2FR is quickly performed and well-tolerated. Lung volumes are highly reproducible and agree well with those obtained with the helium dilution method. Deep inspirations do not seem to overcome gas trapping in patients with CF.     

Long-term reduction of hyperinflation in stable COPD by non-invasive nocturnal home ventilation

OBJECTIVE: The role of non-invasive positive pressure ventilation (NPPV) in stable COPD with chronic ventilatory failure remains controversial. The impact of long-term home nocturnal NPPV treatment on deflation has not yet been evaluated in detail. METHODS: Retrospective explorative study of 46 patients with stable COPD undergoing NPPV treatment. Effects of NPPV on body plethysmographic parameters, blood gas tensions and inspiratory muscle function after 6.2 (+/-1.7) and 12.7 (+/-2.1) months of treatment. Further, evaluation of 1-year survival, compliance and ventilation parameters. RESULTS: One-year survival was 89.1%. The effectiveness of ventilation was proven by a significant reduction in nocturnal and daytime PaCO2. We observed a decrease in the ratio of residual volume (RV) to total lung capacity (TLC) on the average of 5.2+/-9.8% (or 15.2+/-29.7% pred.; P<0.01) at six and 3.9+/-9.0% (or 12.9+/-18.6% pred.; P<0.001) at 12 months. As a consequence, we found significant improvements in inspiratory capacity (IC), vital capacity (VC) and forced expiratory volume in one second (FEV1). For patients with the most severe hyperinflation (RV/TLC>75%), we found a significant positive correlation between inspiratory positive airway pressure (IPAP) and reductions in PaCO2 (r=0.56; P<0.05) and RV/TLC (r=0.50; P<0.05). CONCLUSIONS: In severe hypercapnic stable COPD long-term nocturnal NPPV can reduce hyperinflation with sustained improved daytime blood gas parameters.     

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.     

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.     

Nonreversible airflow obstruction in life-long nonsmokers with moderate to severe asthma.

The aim of this longitudinal study was to assess the frequency of nonreversible airflow obstruction (NRAO) among adults with moderate to severe asthma, and to compare the decline of forced expiratory volume in one second (FEV1) in asthmatics with reversible and nonreversible airflow obstruction. Ninety-two (31 males) life-long nonsmokers with asthma participated in a 10-yr follow-up study; mean age 37 yrs (range 18-64) and duration of asthma 16 yrs (range 2-60) at enrolment. Case history, including use of asthma medication, was obtained, and pulmonary function, including diffusion capacity, was measured using standard techniques. At enrolment, all patients had typical symptoms and reversible airflow obstruction. (NRAO) was defined as FEV1 <80% predicted and change in deltaFEV1 after 5 mg salbutamol <9% pred. A total of 21 (23%) patients (mean age at enrolment 32 yrs) fulfilled the criteria for NRAO at the time of follow-up; current therapy was inhaled steroids (n=21, mean daily dose 1.5 mg), oral steroids (n=14), theophylline (n=20), oral beta2-agonist (n=6) and inhaled beta2-agonist. The patients with NRAO (n=21) had a steeper decline in FEV1 than the remaining patients (n=71, reversible airflow obstruction (RAO)), mean+/-SD 53+/-23 mL x yr(-1) and 36+/-21 mL x yr(-1), respectively (p<0.003). Increasing degree of bronchodilator reversibility (deltaFEV1% pred) at enrolment (p=0.002) and long-term treatment with oral corticosteroids (p=0.009) were associated with an increased risk for the presence of NRAO at follow-up. The comparison of data for NRAO and RAO patients (at follow-up) revealed no significant differences in mean values for total diffusion capacity (TL,CO), diffusion constant (KCO), or total lung capacity. The findings suggest that a subgroup of asthmatics may experience very steep rates of decline in forced expiratory volume in one second leading to severe nonreversible airflow obstruction, whereas no indication was found that long-standing asthma may lead to the development of emphysema.     

Alveolar nitric oxide versus measures of peripheral airway dysfunction in severe asthma.

Alveolar nitric oxide (NO) is a measure of peripheral airway inflammation in asthma, potentially associated with disease severity. The relationship between alveolar NO and physiological tests of peripheral airway (dys)function has not been investigated. The present authors hypothesised that peripheral airway inflammation and dysfunction are inter-related and associated with asthma severity. Alveolar NO was compared between 17 patients with mild-to-moderate asthma and 14 patients with severe asthma and related to total lung capacity (TLC), residual volume (RV)/TLC, thoracic gas volume (FRC), slope of the single breath nitrogen washout curve (dN2), closing capacity (CC)/TLC and fall in forced vital capacity at the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second. In patients with severe asthma, strong correlations were found between alveolar NO and RV/TLC % pred, FRC % pred, dN2, and CC/TLC. Patients with oral steroid-dependent asthma had higher alveolar NO levels (2.7 ppb) compared with the other patients with severe (0.6 ppb) and mild-to-moderate asthma (0.3 ppb). The present authors conclude that alveolar nitric oxide is closely related to parameters of peripheral airway dysfunction in patients with severe asthma, and that oral steroid-dependent asthmatics have more peripheral airway disease than nonsteroid-dependent asthmatics. This suggests that patients on chronic oral steroid treatment have more extensive disease and require additional anti-inflammatory treatment to better target the peripheral airways.     

A pilot study of expiratory flow limitation and lung volume reduction surgery

STUDY OBJECTIVES: To examine the relationships between changes in expiratory flow limitation (FL) during anesthesia and postoperative responses to lung volume reduction surgery (LVRS). DESIGN: Prospective consecutive case comparison. SETTING: University medical center. PATIENTS: Eight patients with severe emphysema. INTERVENTIONS: General anesthesia with muscle paralysis and thoracic epidural analgesia were provided for LVRS via median sternotomy. MEASUREMENTS: FEV(1), functional residual capacity (FRC), and total lung capacity (TLC) were measured preoperatively and 3 months postoperatively. Tidal volume (VT) flow/volume (F/V) curves were obtained with a Pitot-type spirometer. VT, expiratory flow rate at 0. 25 x VT (V'VT,25% ), and peak expiratory flow rate (V'VT,MAX) were obtained from VT F/V curves to derive V'VT,25%/V'VT,MAX ratio as a measure of FL. RESULTS: Closed chest VT F/V curves during anesthesia pre-LVRS showed four patients with FL (group A) whose V'VT,25%/V'VT, MAX ratio was 0.38 +/- 0.06 (mean +/- SD) and four patients without FL (group B) whose V'VT,25%/V'VT,MAX ratio was 0.82 +/- 0.06 (p = 0. 0001). Closed chest post-LVRS V'VT,25%/V'VT,MAX ratio during anesthesia increased by 0.48 +/- 0.08 in group A, compared with a 0. 19 +/- 0.16 reduction in group B (p = 0.0001). Preoperative FEV(1) was 0.57 +/- 0.10 L for group A vs 0.82 +/- 0.13 L for group B (p = 0.02). Postoperative FEV(1) increased by 67 +/- 40% for group A (p = 0.03) vs 29 +/- 21% for group B (not significant). FRC decreased by 33 +/- 3% for group A vs 17 +/- 5% for group B (p = 0.0007), and FRC/TLC decreased by 0.14 +/- 0.05 for group A vs 0.01 +/- 0.07 for group B (p = 0.026). Post-LVRS V'VT,25%/V'VT,MAX ratio change during anesthesia correlated with postoperative reduction in FRC (r(2) = 0. 89, p = 0.0004) and FRC/TLC (r(2) = 0.52, p = 0.045). CONCLUSION: Post-LVRS change in V'VT,25%/V'VT,MAX ratio during anesthesia showed a linear relationship with 3-month postoperative improvement in dynamic hyperinflation. Thus, V'VT,25%/V'VT,MAX ratio may help provide valuable insights into the interactions between chest wall recoil, dynamic hyperinflation, and VT flow rates in patients with severe COPD and LVRS.     

Quantitative air-trapping analysis in children with mild cystic fibrosis lung disease

The purpose of this study was to compare quantitative computed tomography air trapping (AT) and pulmonary function measurements between subjects with mild cystic fibrosis lung disease (MCF; forced expiratory volume in 1 sec (FEV1) > 70% predicted) and normal age-matched controls. Quantitative AT measurements at different levels of expiration were evaluated. Ten subjects from the MCF group and 10 normal subjects underwent inspiratory and expiratory spirometer-triggered chest high-resolution computed tomography (HRCT) and pulmonary function tests. Six matched CT images were obtained at full inflation and at a lung volume near residual volume (nRV). Quantitative measurements of AT were determined by evaluating expiratory CT lung density and by the percent of segmented lung which demonstrated AT on expiratory scans. Percent AT was evaluated for all lung slices combined (global AT), and also by regional assessment. Additional comparisons of lung density and percent air trapping were made in 10 CF subjects with three matched axial HRCT images at lung volumes corresponding to full inflation, near functional residual capacity (nFRC), and nRV. All measurements of expiratory lung density in CF subjects were significantly lower and % AT significantly higher than normal controls. Significant correlations for all subjects were observed between % global AT and RV/TLC as well as forced expiratory flow between 25-75% of forced vital capacity (FEF(25-75)) % predicted. Pulmonary density measurements and % AT better discriminated differences between groups than PFTs. Measurements made on expiratory scans near FRC showed significantly higher values for AT than those made near RV.     

Inspiratory fraction and exercise impairment in COPD patients GOLD stages II-III.

The inspiratory-to-total lung capacity ratio or "inspiratory fraction" (inspiratory capacity(IC)/total lung capacity (TLC)) may be functionally more representative than traditional indices of resting airflow limitation and lung hyperinflation in patients with chronic obstructive pulmonary disease (COPD). In the present retrospective study, a comparison was made of the individual performance of post-bronchodilator IC, IC/TLC and forced expiratory volume in one second (FEV(1)) in predicting a severely reduced peak oxygen uptake (V'(O(2)); <60% predicted) in 44 COPD patients Global Initiative for Chronic Obstructive Lung Disease stages II-III (post-bronchodilator FEV(1) ranging from 31-79% pred). Patients with lower IC/TLC values (相似文献   

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.     

Lung volumes in healthy Afro-Caribbean children aged 4-17 years

Lung volumes in healthy children differ according to their ethnic origin. We wished to determine if any differences in the lung volumes of Afro-Caribbean (AC) children from those predicted by Caucasian reference values disappeared if the results were related to sitting height or to 90% or 77% of lung volumes predicted for height from Caucasian reference values based on standing height. We took, as our working hypothesis, that it is inappropriate to use Caucasian reference values to interpret data from Afro-Caribbean children, and that ethnic-specific reference values are required. This was a prospective, observational study. Subjects included 80 AC children with a median age of 9 (range, 4.3-17.8) years. Standing and sitting height were measured. Lung volumes were measured by body plethysmography (total lung capacity, TLC(pleth); functional residual capacity, FRC(pleth); and vital capacity, VC(pleth)), helium gas dilution (functional residual capacity, (FRC(He)), spirometry (forced expiratory volume in 1 sec, FEV(1)), and forced vital capacity (FVC). The lung volumes of AC children correlated significantly with standing height, but differed significantly from values predicted from Caucasian reference values based on standing height (P < 0.05). Significant differences remained for TLC(pleth), FRC(pleth), FRC(He), RV(pleth), VC(pleth), FEV(1), and FVC when the results were related to sitting height or 90% or 77% of values predicted from Caucasian reference values based on height (P < 0.05). Lung volumes in Afro-Caribbean children should be compared to ethnic-specific reference values.