Obstructive and Restrictive Lung Patterns PDF
Document Details
Uploaded by FastestSlideWhistle5334
University of Liverpool
Anna Rees
Tags
Summary
This document provides a detailed explanation of obstructive and restrictive lung patterns and disorders, including definitions and associated features. It covers the difference between these two types of lung diseases, using charts and diagrams to illustrate the concept. Key factors like FEV1/FVC ratio are also discussed, helping to differentiate between the two conditions. The document concludes with a discussion of how such diseases impact lung volumes.
Full Transcript
Anna Rees Obstructive and Restrictive Patterns Intended Learning Outcomes Describe the difference between obstructive and restrictive lung disease Define FEV1/FVC ratio. Draw a normal graph to represent this and identify and explain both normal and abnormal lines. Un...
Anna Rees Obstructive and Restrictive Patterns Intended Learning Outcomes Describe the difference between obstructive and restrictive lung disease Define FEV1/FVC ratio. Draw a normal graph to represent this and identify and explain both normal and abnormal lines. Understanding lung volumes is important How can because they are affected by disease. Disease affects lung volumes in specific disease affect Loading… patterns, depending on the pathological processes. lung Diseases can be classified as obstructive, restrictive or mixed, with each showing volumes? characteristic changes in lung volumes Effect of disease on lung volumes ERV, Expiratory reserve volume; FRC, functional residual capacity; IRV, inspiratory reserve volume; RV, residual volume; TLC, total lung capacity; TV, tidal volume; VC, vital capacity. Obstructive Disorders This group of disorders is characterized by obstruction of normal air flow caused by airway narrowing, which if not reversed, leads to hyperinflation of the lungs as air is trapped behind closed airways. Loading… The RV is increased as gas that is trapped cannot leave the lung, and the RV:total lung capacity (TLC) ratio increases. In patients with severe obstruction, air trapping can be so extensive that vital capacity is decreased. An example of an obstructive lung disease where a patient develops gas trapping and hyperinflation is chronic obstructive pulmonary disease (COPD). Restrictive Disorders Restrictive disorders result in stiffer lungs that cannot expand to normal volumes. All the subdivisions of volume are decreased and the RV:TLC ratio will be normal or increased (where vital capacity has decreased more quickly than RV). An example of a restrictive lung disorder is Idiopathic pulmonary fibrosis. The forced expiratory volume in 1 second (FEV1) and the forced vital capacity (FVC) are measured using a spirometer. FEV1 and FVC are related to the height, age and sex of the patient. FEV1 is the volume of air expelled in the first second of a forced expiration, starting from full inspiration. FEV1/FVC FVC is a measure of total lung volume exhaled; the patient is asked to exhale with maximal effort after a full inspiration. Ratio The FEV1:FVC ratio is a more useful measurement than FEV1 or FVC alone. FEV1 is 80% of FVC in normal subjects. The FEV1:FVC ratio is an excellent measure of airway limitation and allows us to differentiate obstructive from restrictive lung disease. In restrictive disease: Both FEV1 and FVC are reduced, often in FEV1/FVC proportion to each other Ratio in FEV1:FVC ratio is normal or increased (> 80%) whereas in obstructive diseases: obstructive High intrathoracic pressures generated by forced expiration cause premature closure of the airways and restrictive with trapping of air in the chest disease FEV1 is reduced much more than FVC FEV1:FVC ratio is reduced (< 80%)
