Physiological and morphological determinants of maximal expiratory flow in chronic obstructive lung disease

Maximal expiratory flow in chronic obstructive pulmonary disease (COPD) could be reduced by three different mechanisms; loss of lung elastic recoil, decreased airway conductance upstream of flow-limiting segments; and increased collapsibility of airways. We hypothesized that decreased upstream conductance would be related to inflammation and thickening of the airway walls, increased collapsibility would be related to decreased airway cartilage volume, and decreased collapsibility to inflammation and thickening of the airway walls. Lung tissue was obtained from 72 patients with different degrees of COPD, who were operated upon for a solitary peripheral lung lesion. Maximal flow-static recoil (MFSR) plots to estimate upstream resistance and airway collapsibility were derived in 59 patients from preoperatively measured maximal expiratory flow-volume and pressure-volume curves. In 341 transversely cut airway sections, airway size, airway wall dimensions and inflammatory changes were measured. Airflow obstruction correlated with lung elastic recoil and the MFSR estimate of airway conductance but not to airway collapsibility or to the amount of airway cartilage. The upstream conductance decreased as the inner wall became thicker. Airway collapsibility did not correlate with the amount of airway cartilage, inflammation, or airway wall thickness. We conclude that the maximal flow-static recoil model does not adequately reflect the collapsibility of the flow-limiting segment

Estimation of lung growth using computed tomography

Anatomical studies suggest that normal lungs grow by rapid alveolar addition until about 2 yrs of age followed by a gradual increase in alveolar dimensions. The aim of this study was to examine the hypothesis that normal lung growth can be monitored by computed tomography (CT). Therefore, the gas volume per gram of lung tissue was estimated from measurements of lung density obtained from CT scans performed on children throughout the growth period. CT scans were performed on 17 males and 18 females, ranging in age from 15 days-17.6 yrs. CT-measured lung weight was correlated with predicted post mortem values and CT measured gas volume with predicted values of functional residual capacity. The median value for lung expansion was 1.86 mL x g(-1) at 15 days, decreased to 0.79 mL x g(-1) by 2 yrs and then increased steadily to 5.07 mL x g(-1) at 17 yrs. Computed tomography scans can be used to estimate lung weight, gas volume and expansion of normal lungs during the growth period. The increase in the lung expansion after the age of 2 yrs suggests progressive alveolar expansion with increasing lung volume

Estimation of cancer mortality associated with repetitive computed tomography scanning

Rationale: Low-dose radiation from computed tomography (CT) may increase the risk of certain cancers, especially in children. Objective: We sought to estimate the excess all-cause and cancerspecific mort

Multicentre European study for the treatment of advanced emphysema with bronchial valves

This multicentre, blinded, sham-controlled study was performed to assess the safety and effectiveness of bronchial valve therapy using a bilateral upper lobe treatment approach without the goal of lobar atelectasis. Patients with upper lobe predominant severe emphysema were randomised to bronchoscopy with (n=37) or without (n=36) IBV Valves for a 3-month blinded phase. A positive responder was defined as having both a ≥4-point improvement in St George's Respiratory Questionnaire (SGRQ) and a lobar volume shift as measured by quantitative computed tomography. At 3 months, there were eight (24%) positive responders in the treated group versus none (0%) in the control group (p=0.002). Also, there was a significant shift in volume in the treated group from the upper lobes (mean±SD -7.3±9.0%) to the non-treated lobes (6.7±14.5%), with minimal change in the control group (p<0.05). Mean SGRQ total score improved in both groups (treatment: -4.3±16.2; control: -3.6±10.7). The procedure and devices were well tolerated and there were no differences in adverse events reported in the treatment and control groups. Treatment with bronchial valves without complete lobar occlusion in both upper lobes was safe, but not effective in the majority of patients. Copyright©ERS 2012.SCOPUS: ar.jinfo:eu-repo/semantics/publishe