Diminished Lung Function - what does it mean in diving?

[TSandM]

I was asked to start this thread for the person in question, who doesn't want to have this information identified with her:

Background: Mid-forties female has always been in shape all her life, except for smoking for 10 years, 30 years ago. Blood chemistry is great except cholesterol, which is controlled by diet, exercise, Niaspan, fish oil, and red yeast rice. Chol is down to 183, HDL is 65. Definitely hereditary.

Patient noticed some more "heavy breathing" on normal stair climbs and hikes that she takes. Nothing "bad", but definitely different.

Concerned by the recent spate of heart attacks amongst peer-age divers, she requested and was granted a full heart stress test and echocardio . . whatsit to start a strenuous exercise program. Heart was "fabulous" even with one slightly leaky valve, "nothing to worry about".

Patient was sent for Pulmonary Function tests. PFT tech ran her thru the whole gamut, body plethysmography, the whole bit. Final result:

Forced expiratory flow 25% to 75% was lower than predicted. Everything else -- EVERYTHING -- was "awesome". Gas transfer, volume, etc. Patient was in WONDERFUL shape. . . . except that lower than predicted Forced expiratory flow.

Now, given that everyone exclaims what great shape the patient is, and she is being compared to predictive models of *most of the population*, being low in the forced exp. flow is concerning when everything else was way-better.

The patient has not received final report from Pulmonologists, nor further tests. Given this information, should the patient (who is cleared by the cardiologist to commence on a high-energy exercise program) be concerned about diving while all this "stuff" is being worked out?

 

[Dr. Lecter]

IPF ruled out?

 

[Jax]

IPF ruled out?

I had to look that up. It makes my head hurt!

So is IPF "Idiopathic pulmonary fibrosis" ?

 

[Duke Dive Medicine]

She should get off the red yeast rice - the FDA made the companies remove the statins from those a while back and the ones that didn't comply have a widely varying level of statin in them.

How much lower than predicted was the FEF 25-75? Was the PFT provocative, i.e. performed with dry air? Chest xray and/or CT normal? Are there environmental factors that may influence her breathing? Which valve was "slightly leaky"?

 

[Duke Dive Medicine]

Posting this per the request of the diver in question:

Some indices on the diver's pulmonary function test showed decreased lung flow that improved with administration of a bronchodilator. This indicates possible reactive airway disease, etiology as yet unknown. The recommendation for this diver was not to dive until the cause was addressed and the condition treated, due to the risk of air trapping and hypercapnia (CO2 buildup) secondary to increased gas density while diving.

Best regards,
DDM

 

[Jax]

Many thanks, especially to TSandM for posting, and to Duke Diving Medicine.

I read this: http://www.scubaboard.com/forums/grumpy-old-divers/331950-scuba-diving-killing-older-divers.html

and thought I should continue the story in case others may learn.


Y'all may remember http://www.scubaboard.com/forums/deep-dixie-divers/449710-kevin-carlisle.html. He's ten years younger than I.

After Kevin's mishap which went so incredibly well, I took a close look at myself. After a combine thirty years in the Army, always being the very best and challenging the base for the "top score" in the physical fitness test, the bit of effort I was feeling made me decide to get off my fourth point of contact and get back into serious workouts.

Keeping Kevin in mind, and the fact I smoked for 10 years, 30 years ago, I asked my doc to send me for a stress test and all that stuff. Honestly, I thought I'd get a reformation of what great shape I am in, and go forth, etc.

I got slapped with a look at my own mortality. A leaky valve? "Mitral valve is Myxomatous." "Moderate Mitral insufficiency". "Moderate tricuspid insufficiency." Plus the lung function test thing.

The pulmonologist - whom I haven't seen yet - has no diving concerns because the other factors were so good - 110% plus. They put me on an inhaler, and I'm using it while I am back to running.

My SAC has improved, my blood pressure dropped to normal (from 120/80 to 104/54), and I'm not feeling the slightest bit of breathlessness running the stairs.

That doesn't mean I'm all better. I may have permanent damage from smoking. The pulmonologist will say when he's seen me, after 60 days on the inhaler and jogging a daily mile.



If you have EVER smoked, and you are 50 or older, get checked out. If you have not had a stress test, or echocardiogram, get it done. As much as we'd all like to believe we're in our thirties forever, we are not.

Please don't learn the hard way.

 

[DiverRtNY]

flow and response to a broncho dilator is an obstructive disease. Restrictive disease is based on volume not flow with PFTs. Obstructive diseases are your COPD. Restrictive diseases are your scoliosis and kyphosis (to generalize obstruction vs restriction disease). Anyways... the 25%-75% flow is flow so indicitive of obstruction. This value trends to show an "abnormal" reading prior to the FVC/FEV1 showing a deficiency. FVC (forced vital capacity) is the main indicator that an obstructive "disease" is present. Having the 25-75% low without abnormal values ( <80% of predicted) for FVC shows small obstruction could be apparent. Example would be Asthma (reactive airway). Responding to a broncho dilator would be an example of Asthma. Reactive airway disease isn't asthma but asthma is a form of reactive airway disease. Exercise induced? half the exercises for a PFT are exhausting and can trigger a reactive airway alone. This is a huge generalization for terms used and measurements but it is a basic breakdown with history known. I wouldn't be concerned with air trapping or hypercapnea. My brother has chronic bronchitis and soon to have bronchiectasis d/t an autoimmune deficiency and he doesn't have any problems with his obstructive diseases when diving. Actually feels better but too long to explain. Of course, until they find what is causing her POTENTIAL reactive airway disease, it is best to use caution. If a PRN Albuterol inhaler is prescribed, then a few puffs before diving to relax the smooth muscle won't hurt seeing how the PFT showed improved flow post treatment. I'm not a doctor but I am a Respiratory Therapist. I perform these tests and know a few things about them. But take advice from Pulmonologist...

 

[Jax]

Hey, thank you, RtNY!

I get to see the pulmonologist next week.

I'm on a Combivent Respimat inhaler, 4 x day. Have an awful wheezing cough, now.

BUT my SAC has dropped to .5/.6 cf/min, which is much better than the .9/1.0 I was doing.

I don't know if it is because of the inhaler or because I am running and biking pretty regular now.

 

[Jax]

DAN's Alert Diver Spring 2014 magazine came out with the perfect article under Research, Education, & Medicine.

Tobacco, Marijuana, and Asthma: Differential assessment of dive fitness in smokers and people with asthma.

This article discusses Obstructive Lung Disease, and how tobacco smoking affects breathing chronically and acutely. It specifically points out the decrease in FEB1/FVC and FEF 25-75 respiratory flow measures.

Given that I saw a pulmonologist that normally works with asthma, perhaps he was quick to say "adult-onset-asthma"? I have never had an asthma attack!

Tom Neuman says ..."[smokers] incur the theoretical risk that damage to the airways . . . could cause sufficient outflow obstruction that a air embolism might occur even on a normal ascent. Currently thee is no evidence that smokers with normal airway function have an increased risk of air embolism compared to nonsmokers."

I find it annoying to say "I'm being treated for asthma", when I have zero symptoms of asthma. Also, I have been on the once a day bronchodilator; a recent screening for overseas travel returned completely normal lung function. (Hand held device that measures the same as the big machine.)

So, what does one put on their 'medical' when signing up for a class or a live-aboard?

 

[TSandM]

If you have never been acutely symptomatic, and your PFTs normalized on the steroid inhaler, I'd say on the form that you have asthma, and have your doc sign off on it. Well controlled asthma is no longer a contraindications to diving.

You can have asthma without having severe, acute wheezing episodes. Some people have a chronic cough. Others get wheezy when they have a respiratory infection, but aren't really aware of anything between times. Your PFTs showed an obstructive problem which has resolved with steroids -- whether it's classic asthma or not, it will probably get that label because it's close enough.