The relationship between inspiratory lung function parameters and airway hyper-responsiveness in subjects with mild to moderate COPD.

BACKGROUND: The aim of this study was to evaluate the effects of increasing doses of inhaled histamine on the forced expiratory volume in one second (FEV1), inspiratory lung function parameters (ILPs) and dyspnea in subjects with mild to moderate chronic obstructive pulmonary disease (COPD) METHODS: Thirty-nine (27 males and 12 females) stable COPD patients (GOLD stages I and II) inhaled a maximum of six sequential doses of histamine according to ERS standards until one of these provocative doses produced a 20% decrease in FEV1 (PD20). The effects on the FEV1, the forced inspiratory volume in one second (FIV1), inspiratory capacity (IC), forced inspiratory flow at 50% of the vital capacity (FIF50), peak inspiratory flow (PIF) and dyspnea score by a visual analogue scale (VAS) were measured and investigated after each dose step RESULTS: After each dose of histamine, declines in all of the lung function parameters were detected; the largest decrease was observed in the FEV1. At the PD20 endpoint, more FEV1 responders than ILP responders were found. Among the ILPs, the FIV1 and IC best predicted which patients would reach the PD20 endpoint. No significant correlations were found between any of the lung function parameters and the VAS results CONCLUSIONS: In COPD patients, the FEV1 and ILPs declined after each dose of inhaled histamine. FEV1 was more sensitive to histamine than the ILPs. Of the ILPs, FIV1 and IC were the best predictors of reaching the PD20 endpoint. No statistically significant correlations were found between the lung function parameters and the degree of dyspnea.

Pursed-lips breathing improves inspiratory capacity in chronic obstructive pulmonary disease.

BACKGROUND: In patients with severe chronic obstructive pulmonary disease (COPD), pursed-lips breathing (PLB) improves the pulmonary gas exchange and hyperinflation measured by electro-optic coupling. The response to PLB in inspiratory lung function tests is not known. OBJECTIVES: The purpose of this study was to measure the effect of PLB on inspiratory parameters. METHODS: Thirty-five subjects with stable COPD and a forced expiratory volume in first second (FEV(1)) <50% of the predicted value were tested for the following primary parameters before and immediately after PLB, and 5 min later: forced inspiratory vital capacity, inspiratory capacity (IC), forced inspiratory volume in first second, maximal inspiratory flow at 50% of vital capacity, and peak inspiratory flow. Patients were also tested for the following secondary parameters: vital capacity, FEV(1), breathing frequency, end-tidal CO(2) tension, and oxygen saturation. RESULTS: Of all the primary parameters only IC (p = 0.006) improved significantly; with regard to the secondary parameters, the mean oxygen saturation was improved by 1% (p = 0.005) and the mean end-tidal CO(2) tension and breathing frequency decreased significantly (p < 0.0001 for both) to 3.2 mm Hg and 3.1 breaths/min, respectively. After 5 min the effects diminished. CONCLUSION: Improved IC after PLB indicates less hyperinflation in patients with severe COPD; there was no effect on parameters of flow.

The optimization of the diagnostic work-up in patients with suspected obstructive lung disease.

BACKGROUND: Pulmonary function testing is a key procedure in the work-up of patients who are suspected of having asthma and chronic obstructive lung disease (COPD). Therein, clinical visits and pulmonary function tests (PFTs) are the major contributors to the overall financial costs.The aim of this study was to assess whether a specific diagnostic test protocol contributes to the optimization of the work-up of patients who are suspected of having asthma and COPD. METHODS: A prospective, single-blind, and randomized controlled study was performed. In the control group (CG), all of the PFTs that were ordered by the lung specialist were carried out. In the experimental group (EG), specific PFTs were selected according to our protocol. The primary end point was the total cost of achieving a final diagnosis. RESULTS: One hundred and seventy-nine patients were included into this study: 86 in the CG and 93 in the EG. The mean number of tests to diagnosis was 3.8 in the CG versus 2.9 in the EG (P < 0.001). The mean number of redundant PFTs before diagnosis was 1.2 in the CG versus 0.08 in the EG (P < 0.001). The number of patients who required an additional outpatient visit to complete diagnosis was higher in the CG in comparison to the EG (P = 0.02). The mean cost of work-up per diagnosis was €227 in the CG versus €181 in the EG (P < 0.001). CONCLUSIONS: In this group of patients with suspected obstructive lung disease, protocol-driven, PFT-based selection is more cost-effective than test selection at the discretion of lung physicians.

Random variation of inspiratory lung function parameters in patients with COPD: a diagnostic accuracy study.

BACKGROUND: In chronic obstructive pulmonary disease (COPD), the response of the forced expiratory volume in 1 second (FEV1) after bronchodilator application is weak. Inspiratory parameters like the forced inspiratory volume in 1 second (FIV1) and inspiratory capacity (IC) can be responsive to bronchodilators. In an individual patient with COPD, a significant bronchodilator response must at least exceed the random variation for that parameter. Therefore, it is important that the type of scatter is homoscedastic, as the chance of underestimating or overestimating the random variation for low or high parameter values is minimized. The aim of this study is to investigate the random variation (type and quantity) of inspiratory parameters. METHODS: In 79 stable COPD patients, spirometry was performed. The forced inspiratory volume in 1 second (FIV1), inspiratory capacity (IC), maximal inspiratory flow at 50% (MIF50) and peak inspiratory flow (PIF) were measured five times in one day and again within two weeks of the first measurement. The values of these parameters, taken within one hour, within one day and between two different days, were compared. The coefficient of repeatability (CR) was calculated, and, in addition, linear regression was performed to investigate the type of scatter (homo- or heteroscedastic) of the measured parameters. RESULTS: The type of scatter was heteroscedastic for all of the parameters when the differences were expressed as absolute values; however, when the differences were expressed as the percent change from the initial values, we found a more homoscedastic scatter. The CR within one hour of each parameter expressed as the percent change from the initial value was: IC, 19%; FIV1, 14%; PIF, 18%; MEF50, 21%. CONCLUSIONS: To obtain a more homoscedastic scatter, percentage changes in FIV1, IC and MIF50 are more appropriate than absolute changes. In an individual patient with COPD, a significant improvement for a particular parameter must at least exceed the above-mentioned CR.

Learning curve of conventional transbronchial needle aspiration in pulmonologists experienced in bronchoscopy.

BACKGROUND: Despite its proven efficacy, transbronchial needle aspiration (TBNA) remains an underutilized technique for sampling enlarged mediastinal lymph nodes in the staging of lung cancer. Previous investigators have reported on TBNA experience, but without mentioning individual learning curves related to lymph node size in pulmonologists experienced in bronchoscopy. OBJECTIVES: The aim of this study was to evaluate the TBNA learning curve in a group of pulmonologists already experienced in bronchoscopy, and to relate their yields to lymph node size and location. METHODS: Data on TBNA yield and related lymph node size were collected retrospectively for five individual pulmonologists. RESULTS: The diagnostic yield of five pulmonologists who started to perform TBNA was evaluated over the first 32 months. TBNA was performed on 138 lymph nodes in 119 patients. The overall diagnostic yield was 77% (range 67-91%). The average diagnostic yield increased from 77% at the start of the learning curve to 82% after 32 months of experience. It was related to lymph node size, but not to lymph node location. The average lymph node size was 22 mm. CONCLUSIONS: Satisfactory results were obtained immediately after introduction of TBNA in the bronchoscopy workup. There is no significant TBNA learning curve. The diagnostic yield was related to lymph node size but not to lymph node location.

Recommendations for the measurement of FIV(1) values in chronic obstructive pulmonary disease.

BACKGROUND: In contrast to static inspiratory parameters such as vital capacity and inspiratory capacity, information on forced inspiratory volume in 1 s (FIV(1)) in patients with chronic obstructive pulmonary disease (COPD) is limited. OBJECTIVES: It was the aim of this study to investigate the influence of the preceding expiratory manoeuvre and the optimal number of manoeuvres on FIV(1) values. METHODS: In 169 patients with COPD, FIV(1) manoeuvres were performed after a forced (FIV(1)-Fe) and a slow (FIV(1)-Se) expiration. To investigate the optimal number of the FIV(1)-Se manoeuvres, 8 attempts were performed. RESULTS: The variability of FIV(1)-Fe was greater than that of FIV(1)-Se. The mean difference between FIV(1)-Se and FIV(1)-Fe was 0.21 litres (p < 0.01) and dependent on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage. The higher the GOLD stage, the greater the difference between the 2 techniques. The correlation coefficient between FIV(1)-Se and FIV(1)-Fe was high (r = 0.89, p = 0.01), but there was a poor agreement between these parameters (limits of agreement -0.52 to 0.94 litres). Five manoeuvres were needed to obtain an optimal FIV(1)-Se. There was no association with the GOLD stage. CONCLUSIONS: In COPD patients, FIV(1)-Se are less variable than FIV(1)-Fe, the agreement between the 2 manoeuvres is poor, and at least 5 FIV(1)-Se manoeuvres are needed to get an acceptable FIV(1). This holds for all GOLD stages.

Diagnostic yield of transbronchial histology needle aspiration in patients with mediastinal lymph node enlargement.

BACKGROUND: Transbronchial needle aspiration (TBNA) is a safe, minimally invasive technique to assess the mediastinal spread of lung cancer. Excellent results have been published by experts. However, little information is available about the diagnostic yield of TBNA with the histology needle in a non-expert center. OBJECTIVES: The aim of this study is to assess the diagnostic yield of histology TBNA in the workup of suspected lung cancer. METHODS: In a non-university teaching hospital, TBNA data from patients diagnosed with lung cancer between June 1998 and July 2000 were analyzed retrospectively. TBNA had been performed by six different bronchoscopists in patients eligible for surgery with accessible N2 and N3 lymph nodes on computed tomography of the chest during the workup of an undefined mass. Cytology and histology specimens were obtained with the same 19-gauge needle. TBNA results were considered to be diagnostic if cytologic or histologic examination revealed a malignant lesion or non-malignant lymphoid cells. However, TBNA outcome was called non-diagnostic if no representative cells were obtained. RESULTS: From a group of 264 consecutive lung cancer patients, 106 (40%) patients were eligible for TBNA. In 79%, TBNA was diagnostic in cytology and/or histology specimens. Malignancy was demonstrated in 59% (63/106). In only 32/106 patients (30%), a histologic core of tissue could be sampled. In 87.5% of these patients (28/32), TBNA was diagnostic. For cytology only, this number was slightly lower (75%, 56/74). In 12 cases, diagnostic TBNA was verified by mediastinoscopy: these diagnoses were concordant. The sensitivity is 65% if all non-confirmed cases are considered false negative. Ten mediastinoscopies were avoided because TBNA demonstrated contralateral N2 (= N3) disease. The routine use of TBNA during bronchoscopy in suspected N2 disease is a cost-effective procedure, as the total additional costs of TBNA (9,540 EUR) were lower than the costs of 10 avoided mediastinoscopies (15,500 EUR). No complications were observed. CONCLUSION: The diagnostic yield of TBNA relied mainly on cytology specimens, despite the use of a histology needle. Representative histology specimens could only be obtained in 28/106 patients (26%). Since TBNA was performed in a general hospital by different bronchoscopists, this procedure is useful in the workup of lung cancer patients with enlarged lymph nodes.