The most useful test in the management of obstructive pulmonary disease is Spirometry. This is done with the patient breathing into a tube connected to a recording machine. The patient takes a deep breath in and blows it out as quickly and completely as possible. In addition medications called bronchodilators are administered and the response of the lungs to the bronchodilators can help define the presence and extent of the disease. An ABG is done from a sample of blood drawn from an artery.
Blood drawn from an artery is blood leaving the lungs with a full load of oxygen.
This is another measure of how well the lungs are functioning in getting rid of the waste gas and delivering oxygen to the blood. Many times ABGs are used in more complicated cases of COPD to determine how much addition oxygen a patient needs. This is a non-invasive test involving placing a clip on the finger, earlobe or forehead to indirectly measure the amount of oxygen in the blood. It uses light waves to measure the oxygen levels in the blood. Its advantage is that it can be left in place to monitor levels at rest, during sleep and while walking.