Pulmonary Mucous Plug

[DeepSeaDan]

Dear Diving Doctors,

I once heard tell of a lady physician who was scheduled to dive the upper St. Lawrence on a scuba club venture; problem was, she was recovering from a severe U.R.T infection, and though she felt she was past it, did the prudent thing & conferred with her associates, & also had a chest x-ray. All agreed she was fit to dive.

Her 1st dive was to 100'; the dive itself was uneventful, but she surfaced in severe respiratory distress, then lost conciousness. Efforts at resuscitation proved unsuccessful.

Post mortem showed caused of death to be pulmonary baratrauma due to air entrapment by mucosa, leading to a.g.e.

( Note: I've not been able to verify this story, but even if it proved to be an urban myth, the scenario serves to frame my question ).

So good Physicians, would you please explain to me the physiological mechanics behind such an occurrence; and what, if anything, one can do to further eliminate the guess-work with respect to "fitness-to-dive" , when respiratory infection is the issue.

(P.S. I'm just finishing a course of antibiotics for a particularly nasty chest infection / pneumonia. I was also given a corticosteroid inhaler for a 2 week period...and diving season is nigh! ).

Thank you!

Regards,
DSD

 

[HBO MD]

Not an easy question.
Mucous plugging can occur due to any number of reasons, from inflammation due to infection, through to asthma.
Chest x-ray will not be helpful in detecting it unless there are areas of collapse which are precipitated by the occlusion.
One thing that often goes unrecognized post respiratory infection is post viral bronchial hyper reactivity. This is a transient "asthma" which can last up to 6 weeks post infection and may manifest as an overt wheezing, or an irritable cough at night which is responsive to an inhaler, (bronchodilator). What this does demonstrate is that the respiratory system takes some time to recover after a viral or bacterial illness. The hyper reactivity I speak of may be detected on simple lung function testing, and necessitate ongoing inhaler therapy until clinical resolution.

 

[DeepSeaDan]

Thanks Doc.

I'm scheduled to teach in confined water beginning this Sunday. Based on your description of "post viral bronchial hyper reactivity", I'd say I'm in it. Is the pressure differential in 10' of water a concern?

Regards,
DSD

 

[HBO MD]

Well only so much in that it's a 30% increase in pressure as you already know. What is of concern is that bronchial hyper-reactivity means that your airways are prone to constrict which means there is a risk for gas trapping and it's potential sequelae, such as barotrauma etc. I would honestly try to wait it out if your cough is persistent. I would also see your doctor regarding possibly adding a bronchodilator such as atrovent.
Good luck and a speedy recovery.

 

[cutlass]

....
Is the pressure differential in 10' of water a concern?

....

The risk can be illustrated with some numbers from another recent post:

Roughly speaking, when using mechanical ventilators to assist breathing, the typical limit (plateau pressure or Pplat) is 30cm-H₂O. This is the limit for alveolar tissue. The larger airways have a slightly higher limit at about 45-50cm-H₂O; automatic venting and alarms are typically set around this level.

So put it this way: If a terminal airway (bronchiole) full of air suddenly plugs, a pressure delta from ascending roughly a foot of water is enough to rupture this tiny airway and trailing alveolar air sacs; technically called "volutrauma". If a larger bronchus full of air suddenly plugs, a delta of roughly 1.5ft is enough to rupture it and, of course, everything downstream; the familiar "barotrauma".

I'd chill on the beach for awhile.

 

[DeepSeaDan]

I'd chill on the beach for awhile.

...you might recommend a water bed!

Thanks!

DSD

 

[HBO MD]

Actually I was thinking more of a rubber duck.

 

[hilljo88]

I'm in similar condition: recently recovered from pneumonia. My MD (a diver himself) cautions me to avoid indoor chlorinated pool due to negative impact on healing pulmonary tissue of inhaling chlorine in air. So he won't clear me for 6-8 weeks.