JAMES KING-HOLMES / SCIENCE PHOTO LIBRARY JAMES KING-HOLMES / SCIENCE PHOTO LIBRARY
Lung function test. Asthmatic girl breathes into a vitalograph, a device used to measure lung function. Her asthma causes constric- tion of airways in the lungs (bronchospasm) making breathing difficult. The vitalograph measures lung vital capacity, forced vital capacity, and forced expiratory rate. The age, height and sex of the patient is entered into the vitalograph, which calculates ideal values for the test. The device then displays the patient's performance as a percentage of an ideal value. The test may be taken after bronchodilator drugs to determine the effectiveness of asthma treatment. Photographed at the National Heart and Lung Institute, London.
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