Spirometry is a tool that plays an important role in chronic obstructive pulmonary disease (COPD) from the moment the disease is suspected all the way through its treatment and management. Spirometry is used when a patient complains of breathing difficulties such as shortness of breath, cough, or mucus production and it can detect COPD even in its earliest stage before even before any obvious symptoms manifest.
Along with diagnosing COPD, this tool can also help track progression of disease and assist in staging and even help to determine the best way to proceed with treatment.
How It Works
The testing is done in the doctor’s office using a machine called a spirometer. This handheld device measures your lung function and records the results which are also displayed on a graph. The doctor will ask you to take a deep breath and then blow out into the mouthpiece on the spirometer as hard and fast as you can. It will measure the total amount that were able to exhale which is the forced vital capacity (FVC) as well as how much was exhaled in the first second, which is the forced expiratory volume in 1 second (FEV1). Your FEV1 is also influenced by other factors including your age, sex, height, and ethnicity. The FEV1 is calculated as a percentage of the FVC (FEV1/FVC).
Just as that percentage was able to confirm a diagnosis of COPD, it will also let your doctor know how the disease is progressing.
Tracking COPD Progression
Your doctor will use the spirometer to regularly monitor your lung function and help track the progression of your disease. The test is used to help determine COPD staging and depending on your FEV1 and FVC readings, you will be staged based on the following:
COPD Stage 1 - Mild: Your FEV1 is equal to or greater than the predicted normal values with an FEV1/FVC less than 70 percent. In this stage your symptoms are most likely to be very mild.
COPD Stage 2 - Moderate: Your FEV1 will fall between 50 percent and 79 percent of the predicted normal values with an FEV1/FVC of less than 70 percent. Symptoms are more pronounced, such as shortness of breath on exertion and cough and sputum production.
COPD Stage 3 – Severe: Your FEV1 falls somewhere between 30 percent and 49 percent of the normal predicted values and your FEV1/FVC is less than 70 percent. In this stage shortness of breath, fatigue, and a lower tolerance to physical activity will be evident. Episodes of COPD exacerbation are also common in severe COPD.
COPD Stage 4 – Very Severe: Your FEV1 is less than 30 percent of normal predicted values or less than 50 percent with chronic respiratory failure. At this stage your quality of life is greatly impacted and exacerbations are life threatening.
How Spirometry Assists in COPD Treatment
Regular use of Spirometry for progression tracking is crucial when it comes to COPD treatment. Each stage comes with its own unique issues and understanding what stage your disease is at allows your doctor to recommend and prescribe the best possible treatment for your stage of disease.
While staging assists in the creation of standard treatments, your doctor will take your spirometer results into consideration along with other factors to create a treatment that is personalized to you. Factors such as other comorbidities that may affect your lung capacity further like cardiovascular disease will be a consideration, as will your physical condition when it comes to rehabilitation therapy such as exercise.
Your doctor will schedule regular tests and use the spirometer results to make adjustments to your treatment as needed. This not only includes medications and even recommendation for surgery in some cases, but also lifestyle changes and rehabilitation programs to help improve your symptoms, slow progression, and improve your quality of life.
Spirometry, along with assisting in staging and treatment recommendations, also lets your doctor periodically check whether or not your treatment is working. The results of your tests can tell the doctor whether your lung capacity is stable, improving, or decreasing so that adjustments to treatment can be made.
This simple, inexpensive, and non-invasive test can help a COPD patient through all the various stages of treatment.