There are a number of parameters that are used to quantify respiratory physiology. Each parameter measures a volume of either inspiration or expiration. Measurements of these parameters can be used to identify possible health issues due to respiratory problems. The focus is to visualise lung volumes and capacities of a volunteer, observing respiratory parameters and pulmonary function through normal breathing and simulated asthma. Experimental methodology can demonstrate respiratory parameters through the use of spirometry. A volunteer breathes into a spirometer giving readings of volumes being inspired and expired. Values given can be used in calculation to display FEV1/FVC. The FVC was significantly lower in the obstructed airways compared to normal healthy airways.
Ventilation determines the efficiency of gas exchange between air and blood in the alveolar sacs. Alveolar sacs are alternately aerated and deflated via cyclical breathing movements when a person inspires and expires. Inspiration supplies fresh atmospheric oxygen to the alveoli whilst expiration removes air that lacks oxygen and has high carbon dioxide concentrations. Spirometry is a pulmonary function test using a spirometer. A spirometer is a device that measures the volumes of air that moves in and out of the apparatus, thus measuring ventilation, producing a spirometer trace.
Asthma patients can suffer from shortness of breath (dyspnea), wheezing, coughing and tightness in the chest. This is due to the lining of the airways becoming swollen and inflamed when muscle walls contract during an asthma attack. Asthma attacks occur when airways are obstructed, for example through exposure to dust. During an attack, excess mucus production clogs the airway, and tightening of muscles limits the volume of air able to enter the lungs. Blocked airflow intensifies the effort required to move air in and out of the lungs, hence the breathlessness. The aims of this experiment were to examine lung volumes and capacities, assessing tests of pulmonary function when breathing normally and through obstructed airflow.
The experimental procedure consists of a volunteer breathing into a mouth piece attached to a flow head. Nose clips are required to ensure breathing was only through the mouth. Lung volumes, and capacities are measured, using a spirometer, where the volunteer breathes normally. Measuring parameters of forced expiration consists of a comparison of normal breathing and forced breathing activities where the volunteer inhales maximally and exhales as rapidly and forcefully as possible. Asthma can be simulated through reducing the diameter of the mouth piece, then the volunteer repeats the pulmonary function test. Lung volumes and capacities can then be determined through calculations.