It always seem simple and BORING right up to the time you have an incident or a long term claim on your WCB files, or OHS is pounding on your doors say please show us your prevention programs, then OH why didn’t anyone ever think or why didn’t any one mention this before!
For those of us that are all too familiar with the PFT, we understand that this test evaluates a person’s lung capacity and therefore can be a very useful assessment tool. But what exactly does the PFT measure and why are we required to perform this process multiple times? The fact is, PFTs evaluate different attributes of our lungs’ ability, such as how much air your lungs can hold, how quickly you can move air in and out of your lungs, and how well your lungs put oxygen into the circulatory system while removing carbon dioxide.
These tests can diagnose lung diseases, measure the severity of lung problems, and check to see how well treatment for a lung disease is working. Some of the more prevalent lung functions are: vital capacity, forced vital capacity, and forced expiratory volume. Below is a brief description of these various lung functions: Forced vital capacity (FVC). This measures the amount of air you can exhale with force after you inhale as deeply as possible.
Slow Vital Capacity (SVC) is the maximum volume of air which can be exhaled or inspired in a slow/steady maneuver. Forced expiratory volume (FEV). This measures the amount of air you can exhale with force in one breath. The amount of air you exhale may be measured at 1 second (FEV1), 2 seconds (FEV2), or 3 seconds (FEV3). If a person’s “FEV1 divided by FVC” is less than 0.7 or 70%, there is a concern that there is some type of lung obstruction which can indicate occupational as well as nonoccupational health concerns: most notably, chronic obstructive pulmonary disease or COPD.
Vital Capacity (VC) is the largest of the volumes from either a forced (FVC) or a slow (SVC) maneuver. Even with a normal lung function, a VC that measures less than what is expected (based on age and size of the individual), a substandard VC can indicate an inadequate air supply necessary to support a person’s normal oxygen demand. This could be a limiting factor for an individual where certain tasks would require a high physical demand.
An example would be a work task that would require wearing a respirator. This is because a person with a limiting VC would not be physically capable to function appropriately, due to their “compromised” breathing ability: even though their lung function performance is “normal.” The results of dynamic PFT tests place patients in 1 of 3 categories:
1. normal lung function
2. obstructive disease
3. restrictive disease
The first condition would not warrant any restriction regarding respirator use. Because the 2nd and 3 rd conditions represent medical concerns, especially for respirator use, the examining medical professional may prohibit the use of respirators or extreme physical demand. However, there have been a number of circumstances where, in the case of respirator use, physicians may allow the use of air supplying respirators as these units do not cause increased breathing resistance while drawing air (i.e. inhalation). Should this be the case, it would be typical for an employee’s fit-for-duty evaluation form to have a remark stating that the employee may only wear a powered air purifying respirator or airline respirator.
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