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Smoking (long-term exposure to chemical irritants) can cause COPD, increasing the risk of lung cancer and heart disease. [14] Asthma is a common inflammatory disease causing the airway to swell and disturb breathing and ventilation(low V/A ratio). The cause is unrevealed, but allergens such as pollen, mold, respiratory infections, and air ...
Symptoms of cardiac asthma are related to the heart's inability to effectively and efficiently pump blood in a CHF patient. [2] This can lead to accumulation of fluid in and around the lungs (pulmonary congestion), disrupting the lung's ability to oxygenate blood.
During an asthma episode, inflamed airways react to environmental triggers such as smoke, dust, or pollen. The airways narrow and produce excess mucus, making it difficult to breathe. In essence, asthma is the result of an immune response in the bronchial airways. [3]
Asthma is characterised, in part, by recurrent episodes of reversible airway obstruction; however, in some patients, a degree of irreversible airway obstruction develops over time, leading to lung function decline and fibrosis. Existing airway remodelling may also contribute to bronchoconstriction in acute asthma exacerbations. [1] [2]
Measurement of PEFR requires training to correctly use a meter and the normal expected value depends on the patient's sex, age, and height. It is classically reduced in obstructive lung disorders such as asthma. Due to the wide range of 'normal' values and the high degree of variability, peak flow is not the recommended test to identify asthma.
Emphysema. Collateral ventilation is a back-up system of alveolar ventilation that can bypass the normal route of airflow when airways are restricted or obstructed. The pathways involved include those between adjacent alveoli (pores of Kohn), between bronchioles and alveoli (canals of Lambert), and those between bronchioles (channels of Martin).
The most common cause of emphysema is smoking and smoking cessation is mandatory if this incurable disease is to be treated. Prevention of bronchoconstriction by this pathway is vital for people with emphysema and there are several anticholinergic medications that in combination with mucous thinning agents such as Guaifenesin cause significant ...
The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work. Inhalation is an active process requiring work. [4] Some of this work is to overcome frictional resistance to flow, and part is used to deform elastic tissues, and is stored as potential energy, which is recovered during the passive process of exhalation, Tidal breathing is breathing ...