What is already known about this subject
• Forced expiratory voume in 1 s (FEV1) is the standard measurement used to measure drug effects in chronic obstructive pulmonary disease (COPD) clinical ...trials.
• Having previously shown that specific airway conductance (sGaw) measured using body plethysmography and impulse oscillometry (IOS) are more sensitive than FEV1 for assessing short‐acting bronchodilator effects in patients with COPD, we conducted the first randomized, placebo‐controlled study to compare long‐acting bronchodilators in COPD patients using these techniques.
What this study adds
• sGaw and IOS sensitively differentiated between the effects of tiotropium and salmeterol when FEV1 measurements were similar.
• sGaw and IOS measurements are better than FEV1 for sensitively assessing bronchodilator pharmacology and differentiating between treatments in COPD clinical trials.
Aims
Assessment of bronchodilator pharmacology in chronic obstructive pulmonary disease (COPD) may be improved by using more sensitive methods than spirometry, such as impulse oscillometry (IOS) and body plethysmography. We sought to compare salmeterol (S) and tiotropium (Tio) using these methods.
Methods
In this double‐blind, randomized, four‐way crossover study, 32 COPD patients received single doses of Tio (18 µg), S (50 and 100 µg) or placebo. Specific airway conductance (sGaw), forced expiratory volume in 1 s (FEV1) and IOS were measured pre‐ and up to 26 h postdose. Comparisons between treatments were analysed by weighted means (WM) between 0 and 12 (WM 0–12 h) and 12–24 h (WM 12–24 h) postdose. Data are expressed as mean difference (or geometric ratio for nonparametric data) with 95% confidence intervals.
Results
Tio and S100 significantly improved FEV1, sGaw and IOS parameters up to 26 h and S50 up to 16 h. WM analysis showed no difference between Tio and S100 in FEV1 for 0–12 h or 12–24 h. Maximum mid‐expiratory flow (−0.06; −0.11, −0.01) and R35 (0.02; 0.01, 0.03) demonstrated superiority of S100 compared with Tio for WM 0–12 h sGaw (1.12; 1.02, 1.23), R5 (−0.06; −0.09, −0.02), R15 (−0.03; −0.05, −0.01), and resonant frequency (RF) (−2.30; −3.83, −0.77) showed superiority of Tio compared with S100 for WM 12–24 h. At 26 h, sGaw, R5, R15, X5 and RF also showed superiority of Tio compared with S100.
Conclusions
sGaw and IOS parameters sensitively differentiated between the effects of Tio and S when FEV1 measurements were similar. Clinical trials in patients with COPD should use IOS and sGaw to assess comprehensively bronchodilator pharmacology.
Measuring bronchodilation in COPD clinical trials Borrill, Z. L.; Houghton, C. M.; Woodcock, A. A. ...
British journal of clinical pharmacology,
April 2005, Letnik:
59, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Aims
The aim of this study was to compare the variability and sensitivity of impulse oscillometry (R5, X5 and RF), plethysmography (Raw and sGaw) and spirometry (FEV1, FVC and MMEF) in order to ...determine the most powerful technique for assessing bronchodilation in COPD clinical trials.
Methods
Twenty‐four patients with COPD had impulse oscillometry, plethysmography and spirometry measured twice 30 mins apart, to determine variability. Then ascending doses of salbutamol (20, 50, 100, 200, 400 and 800 µg) were given and the same measurements made after each dose. Significant changes greater than variability were determined for each performed measurement (expressed as mean percentage improvement with 95% CI).
Results
Significant effects (P < 0.05) were detected after 20 µg by X5 (18.5% CI 9.8–27.2) RF (11.1% CI 7.2–15.0) and sGaw (21.5% CI 10.1–32.9), and after 50 µg by R5 (16.7% CI 10.8–22.5) and Raw (19.7% CI 13.0–26.4). FEV1 was less sensitive, detecting significant bronchodilation at 100 µg (10.2% CI 7.4–12.9).
Conclusions
We conclude that impulse oscillometry and plethysmography should be considered the preferred techniques for measuring bronchodilation in COPD clinical trials.
Significant morbidity and mortality offset the benefits of lung volume reduction surgery (LVRS) for emphysema. By contributing to distal lung collapse, bronchoscopic placement of valved prostheses ...has the potential to noninvasively replicate the beneficial effects of LVRS. The purpose of this study was to investigate the safety and feasibility of placing valves in segmental airways of patients with emphysema.
Case series.
Tertiary hospital, severe airways disease clinic.
Ten patients aged 51 to 69 years with apical emphysema and hyperinflation, otherwise suitable for standard LVRS. Mean preoperative FEV(1) was 0.72 L (19 to 46% predicted), and 6-min walk distance was 340 m (range, 245 to 425 m).
Apical, bronchoscopic, segmental airway placement of one-way valves (silicone-based Nitinol bronchial stent; Emphasys Medical; Redwood City, CA) under general anesthesia. Placement was over a guidewire under bronchoscopic and fluoroscopic control.
Four to 11 prostheses per patient took 52 to 137 min to obstruct upper-lobe segments bilaterally. Inpatient stay was 1 to 8 days. No major complications were seen in the 30-day study period. Minor complications included exacerbation of COPD (n = 3), asymptomatic localized pneumothorax (n = 1), and lower-lobe pneumonia (day 37; n = 1). Symptomatic improvement was noted in four patients. No major change in radiologic findings, lung function, or 6-min walk distance was evident at 1 month, although gas transfer improved from 7.47 +/- 2.0 to 8.26 +/- 2.6 mL/min/mm Hg (p = 0.04) and nuclear upper-lobe perfusion fell from 32 +/- 10 to 27 +/- 9% (mean +/- SD) p = 0.02.
Bronchoscopic prostheses can be safely and reliably placed into the human lung. Further study is needed to explore patient characteristics that determine symptomatic efficacy in a larger patient cohort.
The reproducibility of exhaled breath condensate (EBC) mediators is not well documented in chronic obstructive pulmonary disease (COPD). This study assessed within assay (WA), within (WD) and between ...day (BD) reproducibility of EBC leukotriene B4 (LTB4) and 8-isoprostane. Three EBC samples were collected from 24 COPD patients separated by 1 h and 1 wk, to assess WD and BD reproducibility. WA reproducibility was assessed by sample analysis by enzyme immunoassay in triplicate. WA coefficient of variation for LTB4 and 8-isoprostane (18.2% and 29.2%, respectively) was lower than corresponding values for WD (47.7% and 65.3%, respectively) and BD (75.7% and 79.1%, respectively). Repeatability coefficient for 8-isoprostane and LTB4 assays were 18.6 pg/ml and 13.2 pg/ml, respectively. Group mean differences for WD and BD were small and statistically nonsignificant. Using the Bland Altman method, there were wide limits of agreement for WD (-51.6 to 47.2 for 8-isoprostane and -31.8 to 31.4 for LTB4) and BD reproducibility (-61.4 to 75.7 for 8-isoprostane and -29.3 to 38.6 for LTB4). This is the first study to fully report the variability of EBC 8-isoprostane and LTB4 in COPD. WA variability and group mean changes were small. However, we observed considerable WD and BD variability for these biomarkers.
This study compared the effect of inhaled fluticasone propionate (FP) with the combination of salmeterol/fluticasone propionate (SFC) on lung function parameters in patients with mild asthma.
Adult ...patients with mild persistent asthma (> or = 80% predicted FEV1) receiving 200-500 mug of BDP or equivalent were randomised to receive either FP 100 mug or SFC 50/100 mug twice daily from a Diskus inhaler for four weeks. The primary outcome was the change from baseline in airway resistance (sRaw) at 12 hrs post dose measured by whole body plethysmography. Impulse oscillometry and spirometry were also performed.
A comparison of the geometric mean sRaw at 12 hrs post dose in the SFC group to the FP group gave a ratio of 0.76 (0.66 - 0.89, p < 0.001) at week 2 and 0.81 (0.71 - 0.94, p = 0.006) at week 4. Similarly, significant results in favour of SFC for oscillometry measurements of resistance and reactance were observed. FEV1 was also significantly superior at week 2 in the SFC group (mean difference 0.16L, 95% CI; 0.03 - 0.28, p = 0.015), but not at week 4 (mean difference 0.17L, 95% CI -0.01 - 0.34, p = 0.060).
SFC is superior to FP in reducing airway resistance in mild asthmatics with near normal FEV1 values. This study provides evidence that changes in pulmonary function in patients with mild asthma are detected more sensitively by plethysmography compared to spirometry
NCT00370591.
Limited information exists regarding measurement, reproducibility and interrelationships of non-invasive biomarkers in smokers. We compared exhaled breath condensate (EBC) leukotriene B4 (LTB4) and ...8-isoprostane, exhaled nitric oxide, induced sputum, spirometry, plethysmography, impulse oscillometry and methacholine reactivity in 18 smokers and 10 non-smokers. We assessed the relationships between these measurements and within-subject reproducibility of EBC biomarkers in smokers. Compared to non-smokers, smokers had significantly lower MMEF % predicted (mean 64.1 vs 77.7, p = 0.003), FEV1/FVC (mean 76.2 vs 79.8 p = 0.05), specific conductance (geometric mean 1.2 vs 1.6, p = 0.02), higher resonant frequency (mean 15.5 vs 9.9, p = 0.01) and higher EBC 8-isoprostane (geometric mean 49.9 vs 8.9 pg/ml p = 0.001). Median EBC pH values were similar, but a subgroup of smokers had airway acidification (pH < 7.2) not observed in non-smokers. Smokers had predominant sputum neutrophilia (mean 68.5%). Repeated EBC measurements showed no significant differences between group means, but Bland Altman analysis showed large individual variability. EBC 8-isoprostane correlated with EBC LTB4 (r = 0.78, p = 0.0001). Sputum supernatant IL-8 correlated with total neutrophil count per gram of sputum (r = 0.52, p = 0.04) and with EBC pH (r = -0.59, p = 0.02). In conclusion, smokers had evidence of small airway dysfunction, increased airway resistance, reduced lung compliance, airway neutrophilia and oxidative stress.
Significant morbidity and mortality offset the benefits of lung volume reduction surgery (LVRS) for emphysema. By contributing to distal lung collapse, bronchoscopic placement of valved prostheses ...has the potential to noninvasively replicate the beneficial effects of LVRS. The purpose of this study was to investigate the safety and feasibility of placing valves in segmental airways of patients with emphysema.
Case series.
Tertiary hospital, severe airways disease clinic.
Ten patients aged 51 to 69 years with apical emphysema and hyperinflation, otherwise suitable for standard LVRS. Mean preoperative FEV1 was 0.72 L (19 to 46% predicted), and 6-min walk distance was 340 m (range, 245 to 425 m).
Apical, bronchoscopic, segmental airway placement of one-way valves (silicone-based Nitinol bronchial stent; Emphasys Medical; Redwood City, CA) under general anesthesia. Placement was over a guidewire under bronchoscopic and fluoroscopic control.
Four to 11 prostheses per patient took 52 to 137 min to obstruct upper-lobe segments bilaterally. Inpatient stay was 1 to 8 days. No major complications were seen in the 30-day study period. Minor complications included exacerbation of COPD (n = 3), asymptomatic localized pneumothorax (n = 1), and lower-lobe pneumonia (day 37; n = 1). Symptomatic improvement was noted in four patients. No major change in radiologic findings, lung function, or 6-min walk distance was evident at 1 month, although gas transfer improved from 7.47 ± 2.0 to 8.26 ± 2.6 mL/min/mm Hg (p = 0.04) and nuclear upper-lobe perfusion fell from 32 ± 10 to 27 ± 9% (mean ± SD) p = 0.02.
Bronchoscopic prostheses can be safely and reliably placed into the human lung. Further study is needed to explore patient characteristics that determine symptomatic efficacy in a larger patient cohort.
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