Pulmonary functiont test

[Carlos Alberto]

Hello

I'm planning to see a pulmonologist for a pulmonary function test (PFT) to Gaby. I wish to know what I should expect of this test in numbers.

Can anybody tell me how is the PFT result?

Greetings

Carlos

[LindaRacine]

Hi Carlos...

You might want to move this thread to the Parents section. (You've posted in the teens section.)

From this website:
http://www.meddean.luc.edu/lumen/Med...llow/exam2.htm

Pulmonary function tests can be divided into 6 parts: Air flow, Maximum voluntary ventilation, lung volumes, diffusion of carbon monoxide, flow volume loop and arterial blood gases.

Airflows

This is the KEY to detecting OBSTRUCTION! The patient is instructed to breath out as hard and fast and completely as possible from a full inspiration. Most importantly are:

FEV1, Forced expiratory volume in 1 second
FVC, forced vital capacity
Ratio of FEV1/FVC less than 75% defines OBSTRUCTION!

All other flows may support or suggest obstruction but the definition rest with the ratio of FEV1/FVC.

Maximum Voluntary Ventilation

This is a test of the patients ability to breath in and out as hard and fast as possible for 10 seconds (liters/min).

This number should be approximately 40 times the FEV1.

This test reflects effort and correlates in general with overall pulmonary function.

Lung Volumes

This test may be performed using helium dilution technique or by body plethysmography.

The KEY lung volume is TLC (total lung capacity).

TLC < 80% of predicted value = restriction.
TLC > 120% of predicted value = hyperinflation.

Increased RV residual volume and increased RV/TLC ratio both imply airtrapping.

Diffusion Capacity

This is a test of the ability of inhaled carbon monoxide to diffuse into the pulmonary circulation.

It is dependent on functional alveolar capillary membrane surface area and red blood cells within the circulation.

It is reduced when ever there is a loss of functional alveolar capillary membrane surface area or decrease in hemoglobin.

The diffusion capacity is "corrected" for lung volume by dividing by VA (alveolar volume). This gives a an estimate of the diffusion capacity of the lung volume that is present.

Flow Volume Loop

Graphic display of simultaneously obtained lung volume versus airflow can be useful to get an overall view of the pulmonary function. Most importantly however, it can suggest upper airway obstructions.

Arterial Blood Gases

Acid base balance is examined and the Alveolar:arterial oxygen gradient are calculated. A:a gradient on room air can be estimated by :

(150 - pCO2*1.25) - arterial pO2

This should be less than 9 age 20, less than 24 age 80.

[Carmell]

Hi Carlos,

PFT's are part of Braydon's annual "routine" tests. It gives the docs a good idea of what the patient's overall lung function is. It also gives them a good baseline to have in the future, if needed. They like to know the baseline so that if Gaby ever has corrective surgery for her spine issues, they can determine if her lungs are responding well or if there is more they need to do for the lungs.

PFT's can be difficult for young children. Braydon was 5yrs old when he had his first PFT. He cooperated very well, and has cooperated well since. Sometimes they aren't able to get a good reading because the child doesn't understand or is afraid. You can help her by prepping her. Tell her that they will be having her blow into a tube with her mouth. You could use a drinking straw, but the mouthpiece is actually very large - she'll have to open her mouth very wide to get it in. Then they will plug her nose so she can not breathe through her nose, only through her mouth. If she can do this part, the rest is just following instructions on how to breathe (ie, breathing fast, short/quick breathes, deep breathes in and out, etc.).

Let me know how things go.

[Carlos Alberto]

Hi Linda and Carmell

Thanks for your posts.

Today I was in the hospital and I talked with the person who make the test. I learned the procedure and now I will train Gaby. I will let you know the result.

The PFT here is only one test. Gaby should breath as much as she can and after this blowing with her mouth all the air into the tube.

Greetings

Carlos

[lorrie]

Hi Carlos
Just wanted to say hello cos we haven't seen any posts from you for quite a while. How are things going with you people?

Lorrie

[Carlos Alberto]

Pft

Hello

My experience with the PFT of Gaby was very frustrating. The one in charge of making the test told us that Gaby won't cooperate. My wife insisted him in that she was trained and that she will cooperate but they told her that anyway the test is only good for children bigger than six years. Gaby completes the 6 in April.

Greetings

Carlos