The pulmonary function test sounds like only one test, but it consists of multiple tests which if you don’t ask questions you would not have known about them. When just observing the lung function test one would see all patients blowing into a mouth piece for 8 hours and not think much of it. On being more interactive with the clinical technicians I was able to distinguish three very specific tests that are used to obtain a complete evaluation of the patient’s respiratory condition. These tests are not the only tools used to evaluate the respiratory conditions it also includes physical examinations, patient history, chest x-rays and arterial blood gas analysis.
Flow Volume Loop
The flow-volume loop test otherwise known as …show more content…
Helium concentration is measured until an equilibrium is reached between in and exhaled air. This calculates the change in helium concentration that has occurred and indicates the equilibration of gas volume in the lungs. This test measures Functional Residual Capacity (www.merckmanuals.com, …show more content…
The patient sits in an airtight glass box; the patient now begins to inhale against a closed mouth piece to test Functional Residual Capacity. As the chest wall expands, the pressure in the box rises. Calculations are then made by using the pre-inspiration box volume and the pressure in the box before and after the inhalation effort. The Functional Residual Capacity represents 40% of the Total Lung Capacity (merckmanuals.com, 2014).
Obstructive and restrictive lung disease
In a restrictive lung disease the lung compliance is reduced. This means that the lungs become stiffer which negatively affects lung expansion. In these cases a greater pressure than normal is required to increase the lung volume. Common causes of decreased lung compliance are pulmonary oedema, pulmonary fibrosis and pneumonia.
(ugr.es.com, 2014)
In obstructive lung disease the airway obstruction causes an increase in airway resistance. With obstructive lung disease the pressure volume relationship is no different from a normal lung, but when the breathing rate increases greater pressures are needed to overcome the resistance to airflow causing the volume of each inspiration to become less. Common obstructive diseases include emphysema, bronchitis and