Idiopathic pulmonary fibrosis: new insights on functional characteristics at diagnosis.

BACKGROUND: The lung function of patients with idiopathic pulmonary fibrosis (IPF) has not been characterized in detail. objective: To characterize the heterogeneous physiological abnormalities that exist in patients with IPF during their initial clinical evaluation. METHODS: Lung function tests from 93 patients, performed within six months of the initial diagnosis of IPF, were obtained from a referral pulmonary function laboratory at a tertiary care hospital in Canada. A restrictive pattern was defined as total lung capacity (TLC) <95th percentile of predicted value. Patients with obstructive lung disease, lung cancer, emphysema and other restrictive lung diseases were excluded. RESULTS: On diagnosis, 73% of patients with IPF had a restrictive pattern, with a mean TLC of 72% of predicted. Mean forced vital capacity (FVC) was 71% and 44% of patients had an FVC <95th percentile. Mean diffusing capacity for carbon monoxide (DLCO) was 60% and DLCO/alveolar volume (VA) 92% of predicted. Increased severity of restriction - based on TLC - was associated with lower DLCO (74% of predicted in mild restriction and 39% of predicted in severe restriction) and higher forced expiratory volume in 1 s (FEV1)/FVC ratio (82% of predicted in mild restriction and 90% of predicted in severe restriction) but not with age (76 years in mild restriction and 69 years in severe restriction). Regardless of severity of restriction, the average DLCO/VA (≥86% of predicted) remained within normal limits. CONCLUSIONS: One in four patients with IPF had normal TLC and more than one-half had a normal FVC during initial evaluation. As the severity of the restriction increased, FEV1/FVC increased, DLCO decreased but DLCO/VA remained normal.

Flock worker's lung disease: natural history of cases and exposed workers in Kingston, Ontario.

BACKGROUND: The natural history of flock worker's lung (FWL) and longitudinal lung function changes in nylon flock-exposed workers have not been well characterized. METHODS: Symptoms, pulmonary function testing, and chest radiographs from five index cases, subsequent case referrals, and screened employees of a flocking plant in Kingston, Ontario, Canada, were compared and analyzed for changes over time (variable follow-up intervals between 1991 and 2011). RESULTS: Nine cases and 30 flock-exposed workers without FWL were identified. Four cases had persistent interstitial lung disease despite three having left the workplace. Two developed hypoxemic respiratory failure and secondary pulmonary hypertension and died of complications 18 and 20 years after diagnosis, respectively. Five cases resolved after leaving the workplace. Compared with resolved cases, persistent cases had lower diffusing capacity of the lung for carbon monoxide at presentation (P < .05) and follow-up (P < .05). Among exposed workers employed for 14.5 ± 4.7 years, five had abnormal chest radiographs vs none at baseline (P = .001) over 14.8 ± 4.6 years of follow-up. The prevalence of wheeze increased (P = .001), and FEV1/FVC decreased (P < .001). FEV1% predicted was significantly lower at follow-up (P = .05). Average FEV1 decline was 46 mL/year (range, -27 to 151 mL/y). Seventy-seven percent of exposed workers were current or former smokers. CONCLUSIONS: The natural history of FWL includes the following patterns: complete resolution of symptoms; radiographic and pulmonary function abnormalities; permanent, but stable symptoms and restrictive pulmonary function deficits; and progressive decline in pulmonary function, causing death from respiratory failure and secondary pulmonary hypertension. A low baseline diffusing capacity of the lung for carbon monoxide is associated with the persistence and progression of FWL.

Effects of BMI on static lung volumes in patients with airway obstruction.

BACKGROUND: Both chronic airway obstruction and obesity are increasing in prevalence but the effect of their combination on pulmonary function parameters across the range of airway obstruction is unknown. METHODS: We studied the impact of increasing BMI on static lung volumes and airway function in a cohort of 2,265 subjects from a large pulmonary function laboratory database who were 40 to 80 years of age and met GOLD (Global Initiative for Chronic Obstructive Lung Disease) spirometric criteria for COPD (postbronchodilator FEV1/FVC < 0.7). We also evaluated the influence of severity of airway obstruction (by GOLD criteria) on these relationships. RESULTS: With increasing BMI in the group as a whole, functional residual capacity, residual volume, expiratory reserve volume, and specific airway resistance (sRaw) decreased exponentially (all P < .001); total lung capacity (TLC) decreased linearly (P < .001); and inspiratory capacity (IC) and IC/TLC increased linearly (P < .001). However, vital capacity was not influenced significantly. The effects of increasing BMI on FEV1/FVC and sRaw were greatest in GOLD stage III/IV (P < .05), whereas increasing BMI had greater effects on IC in GOLD stage I (P < .001). CONCLUSIONS: With increasing BMI, subjects with airway obstruction had consistent reductions in lung hyperinflation, with significant improvements in IC and the FEV1/FVC ratio; this effect was greatest in patients with the most severe airway obstruction. These results have important implications for the clinical assessment of patients with combined obesity and airway obstruction.

Lung hyperinflation and its reversibility in patients with airway obstruction of varying severity.

The natural history of lung hyperinflation in patients with airway obstruction is unknown. In particular, little information exists about the extent of air trapping and its reversibility to bronchodilator therapy in those with mild airway obstruction. We completed a retrospective analysis of data from individuals with airway obstruction who attended our pulmonary function laboratory and had plethysmographic lung volume measurements pre- and post-bronchodilator (salbutamol). COPD was likely the predominant diagnosis but patients with asthma may have been included. We studied 2,265 subjects (61% male), age 65 ± 9 years (mean ± SD) with a post-bronchodilator FEV(1)/FVC <0.70. We examined relationships between indices of airway obstruction and lung hyperinflation, and measured responses to bronchodilation across subgroups stratified by GOLD criteria. In GOLD stage I, vital capacity (VC) and inspiratory capacity (IC) were in the normal range; pre-bronchodilator residual volume (RV), functional residual capacity (FRC) and specific airway resistance were increased to 135%, 119% and 250% of predicted, respectively. For the group as a whole, RV and FRC increased exponentially as FEV(1) decreased, while VC and IC decreased linearly. Regardless of baseline FEV(1), the most consistent improvement following bronchodilation was RV reduction, in terms of magnitude and responder rate. In conclusion, increases (above normal) in airway resistance and plethysmographic lung volumes were found in those with only minor airway obstruction. Indices of lung hyperinflation increased exponentially as airway obstruction worsened. Those with the greatest resting lung hyperinflation showed the largest bronchodilator-induced volume deflation effects. Reduced air trapping was the predominant response to acute bronchodilation across severity subgroups.

Massive pulmonary hemorrhage from dual circulation pulmonary arteriovenous malformations in hereditary hemorrhagic telangiectasia.

Pulmonary arteriovenous malformations (AVMs) are commonly supplied by the pulmonary arterial system and rarely by the systemic bronchial circulation. The authors outline the case of a young woman with pulmonary AVMs as part of hereditary hemorrhagic telangiectasia with the uncommon presentation of massive hemoptysis. Management of her recurrent, life-threatening pulmonary hemorrhage was complicated by pulmonary AVMs that were supplied by both the pulmonary and systemic bronchial arterial circulatory systems. Transcatheter embolotherapy of the higher pressure bronchial systemic circuit was necessary for acute hemostasis.

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.