Mandatory Thoracic CT Scan for Divers?

[DeepSeaDan]

Greetings,

Was reading an older published paper ( 2003 ) the other day where the premise was the question of whether "Professional Divers" should be required to undergo a chest ct scan, to look for "pulmonary air-trapping lesions." In his words:

"Chest x ray examination is mandatory for medical certification of the professional divers in many countries, but pulmonary air trapping lesions such as an air cyst in the lungs cannot always be detected by plain chest x ray examination. Computed tomography (CT) is a reliable, but expensive measure for detecting pulmonary abnormalities in divers."

He went on to say:

"One of the purposes of the chest x ray examination is to check for the presence of lung cysts, emphysematous blebs, or bullae, which might predispose pulmonary barotraumas (PBT) and preclude diving."

The author then related several case studies of instances where air-trapping issues were evident.

Two questions: Are there more recent studies concerning this issue? Should such thoracic imaging be mandatory for the entry-level recreational diver?

DSD

 

[rsingler]

It becomes a cost-benefit thing. With hundreds of thousands of recreational divers (of varying physical health) serving as test subjects, if pulmonary blebs not recognized by a dive physician were common, we'd see case reports of barotrauma.
Professional divers are not, in most cases, at greater risk because bounce divers (rec) have more frequent reexpansion stress than a "one-and-done" pro diver even if deco is required.

Having said all this, I now predict that the next decade will show an increase in just the sort of barotrauma-induced injury you are asking about. Now, however it will be due to unrecognized COVID-induced scarring and destruction of alveolar anatomy.
Whether that increase in reexpansion pulmonary injury (if it occurs) prompts a new requirement for pulmonary evaluation post-COVID in preparation for diving certification remains to be seen. It will be expensive.

Diving Doc

 

[DeepSeaDan]

It becomes a cost-benefit thing. With hundreds of thousands of recreational divers (of varying physical health) serving as test subjects, if pulmonary blebs not recognized by a dive physician were common, we'd see case reports of barotrauma.
Professional divers are not, in most cases, at greater risk because bounce divers (rec) have more frequent reexpansion stress than a "one-and-done" pro diver even if deco is required.

Having said all this, I now predict that the next decade will show an increase in just the sort of barotrauma-induced injury you are asking about. Now, however it will be due to unrecognized COVID-induced scarring and destruction of alveolar anatomy.
Whether that increase in reexpansion pulmonary injury (if it occurs) prompts a new requirement for pulmonary evaluation post-COVID in preparation for diving certification remains to be seen. It will be expensive.

Diving Doc

Thanks Doc.

I believe two of the 3 case studies featured in the paper involved patients with a history of smoking. I suspect divers whose medical &/or lifestyle histories may make them more susceptible ( eg: un-diagnosed copd folks ) would be at greater risk. I have a friend whose been a dry-waller all his working life who confided to me he has a less-than-normal O2 sat. and gets short of breath with exertion. He got certified to dive and as yet has not heeded my advice to talk to his physician about his cardio-pulmonary health.

I'm a great believer & advocate for a proactive approach to health & wellness.

At the very least, I'd like to see this potential problem related to the recreational diving population at large, so folks who may be at risk can be informed and have the opportunity to seek medical evaluation.

DSD

 

[Esprise Me]

I'm not a medical professional, so take my experience for what it's worth.

My husband suffered a spontaneous pneumothorax when he was in his late teens. It happened on land; he survived, but it was serious enough to require surgery. He fit the at-risk profile as a tall skinny adolescent guy, but he wasn't a smoker, didn't have any personal or family history of pneumothorax or any related issues, and had even dabbled in scuba diving without issue. (He went to a schmancy high school that offered that as a P.E. option.) Many years later, we wanted to get certified together, but were stymied by the contraindication against diving after spontaneous pneumothorax. He visited a pulmonologist with some dive medicine training, who essentially told him they could do a scan, but that even if they couldn't see any blebs on it, that wouldn't mean there weren't any that were big enough to cause problems, and that he'd still be considered at greater risk than someone who'd never had a spontaneous pneumothorax. My husband decided to play it safe and not dive, so he didn't bother with the CT.

Given what the doctor told him, I wonder how much value a CT scan would offer the average person thinking of taking up diving. It might catch some blebs in people who had no reason to think they were at risk. That might discourage those people from diving, and that might save their lives. But that's a lot of "mights." If my husband's doctor was right and wasn't just being overly cautious, any of us could have undetectable blebs just waiting to kill us. But on the other side, I wonder, what is the likelihood of a person with blebs that could eventually lead to spontaneous pneumothorax suffering that fate during a dive? My husband got away with his high school diving, only to be hit on land with his innate vulnerability. Whatever blebs may remain in his lungs have caused him no problems in the intervening decade and a half. So how much would a CT performed at any point in his life have told him about his actual risk? How much would it tell me about mine? How often are people like me--avid divers with no reason to suspect we're at risk--screened, and do any of us turn out to have blebs that just never caused a problem?

 

[Duke Dive Medicine]

Greetings,

Was reading an older published paper ( 2003 ) the other day where the premise was the question of whether "Professional Divers" should be required to undergo a chest ct scan, to look for "pulmonary air-trapping lesions." In his words:

"Chest x ray examination is mandatory for medical certification of the professional divers in many countries, but pulmonary air trapping lesions such as an air cyst in the lungs cannot always be detected by plain chest x ray examination. Computed tomography (CT) is a reliable, but expensive measure for detecting pulmonary abnormalities in divers."

He went on to say:

"One of the purposes of the chest x ray examination is to check for the presence of lung cysts, emphysematous blebs, or bullae, which might predispose pulmonary barotraumas (PBT) and preclude diving."

The author then related several case studies of instances where air-trapping issues were evident.

Two questions: Are there more recent studies concerning this issue? Should such thoracic imaging be mandatory for the entry-level recreational diver?

DSD

Plain film chest x-rays are still used for commercial divers - see the physical requirements on the ADCI website. Spirometry (pulmonary function testing) is also required. Together, they are considered sufficient to detect clinically significant lung pathology.

It's a fair question as to why this isn't required of recreational divers. Commercial divers are screened much more carefully, partly because the work they do is generally more physically demanding, and also partly because the diving companies do not want divers being injured on the job. Concur with @rsingler and @Esprise Me in that it comes down to cost vs benefit and frequency of occurrence.

@Esprise Me : the thinking has evolved some on spontaneous pneumothorax, and it's no longer a blanket disqualifier for recreational diving. Your husband might consider seeing a diving physician if it's still something he wants to pursue - there are some good ones in the LA area.

Best regards,
DDM

 

[Esprise Me]

@Duke Dive Medicine Has the thinking evolved toward screening methods being more conclusive about ruling out elevated risk? Genuinely curious. It was within the last few years that my husband saw the pulmonologist. And it wasn't like he said "absolutely don't dive"; more like "I can't promise you don't have an invisible ticking time bomb in there," which was enough for my husband to take a pass.

I spend a fair amont of time ruminating on risk and justification. I consider myself generally risk-averse, but diving has become a passion that makes me more willing to take risks that I would otherwise blanch at. My husband is also pretty risk-averse, and doesn’t want to dive quite as badly as I do. Even if we could have perfect data, there's a tricky emotional calculus on the back end.

 

[Duke Dive Medicine]

@Duke Dive Medicine Has the thinking evolved toward screening methods being more conclusive about ruling out elevated risk? Genuinely curious. It was within the last few years that my husband saw the pulmonologist. And it wasn't like he said "absolutely don't dive"; more like "I can't promise you don't have an invisible ticking time bomb in there," which was enough for my husband to take a pass.

I spend a fair amont of time ruminating on risk and justification. I consider myself generally risk-averse, but diving has become a passion that makes me more willing to take risks that I would otherwise blanch at. My husband is also pretty risk-averse, and doesn’t want to dive quite as badly as I do. Even if we could have perfect data, there's a tricky emotional calculus on the back end.

Screening, how the spontaneous pneumo was treatet, and time elapsed since the event. Completely understand the decision process and it sounds like you all have your heads around it pretty well, just wanted you to know that in some circles it's no longer considered an absolute contraindication.