It would depend on whether there is any risk of air trapping or decrement in exercise tolerance as others have noted. It's at least worth asking a diving physician. Where is your spring chicken located?
Best regards,
DDM
Diving without part of a lung
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Best regards,
DDM
RCTs don't give definitive answers either, and you probably won't see one for this. That's why it's so important to have physicians with a strong background in diving medicine to assess individual risk and offer tailored advice.
Best regards,
DDM
While RCTs often cannot give a definitive answer, a well done, randomized control trial can certainly offer significant insights into the effectiveness or viability of a treatment or screening program.
In this instance, it certainly would be possible to design a trial to randomize evaluation prior to renewing diving versus no evaluation or perhaps versus evaluation with testing and over a period of time see if any of the three modalities caused or avoided more injuries and at what cost.
Although I will admit I have not done the power calculations, my own WAG would be that a very large trial would be needed to demonstrate any statistically significant effect and would call into question the effectiveness as well as viability from a cost aspect of a pre-dive screening program after illness; especially one that involves any degree of testing or advanced imaging for otherwise well appearing individuals.
This is why I agree we are unlikely to see any such study. Unfortunately, this often means we default back to the standard dogma of physician evaluation prior to diving after anything but the most benign illness or injury even though I question how much safer divers are because of it.
We're talking here about a person who may have had a lobectomy related to severe pneumonia (though admittedly the OP isn't sure). How would you ensure that (a) there's no air trapping and (b) the diver can tolerate underwater exercise? Or, would you just clear him to dive if he feels ok as you mentioned above?
Best regards,
DDM
I don’t believe there is any way we can fully exclude air trapping.
CT scans are commly referred used for such exams, but studies have noted that what appears to be air trapping on CT does not always equate to findings on a pulmonary function test.
Additionally some studies have noted that what appear to be healthy individuals frequently have some air trapping noted on CT scan. The same study also noted that single inspiratory view CTs may not be sufficient and postulate that both inspriatory and expiratory scans are required. This causes me to question if CT findings are reliable enough to predict who can and cannot safely dive
Expiratory CT scan in patients with normal inspiratory CT scan: a finding of obliterative bronchiolitis and other causes of bronchiolar obstruction - PMC
Expiratory CT scan is usually obtained as supplement to normal inspiratory CT scan to recognize air-trapping, which is expression of small airways obstruction. In some patients the air-trapping may be the only sign of an early-stage small airways ...
pmc.ncbi.nlm.nih.gov
Finally an article from military medicine discussed the usefullness of PFT and chest CT in determining who may be at risk for barotrauma from diving. The discussion is from case series and discusses returning to diving after barotrauma related to diving without violating dive procedures (so an “unexplained” barotrauma)
The weakness of this article, and of many studies related to risk of diving, is the lack of a true denominator. Thousands of divers go underwater each day and nearly all of them do just fine. Undoubtedly a good percentage of them have some degree of COPD, Asthma, or other potential causes of air trapping in the lungs. What percentage would you guess have air trapping in their CT or less than ideal PFTs but still continue to dive safely?
That becomes the rub of my trepidation with screening physicals. We don’t have a crystal ball, and while the extreme cases certainly offer easier insights; if you are not physically fit enough to walk a flight of stairs, you’re likely not physically fit enough to dive, for individuals who feel healthy it becomes much more difficult to predict the future, good or bad.
To answer your final question - if the individual in question is several years out from his injury/illness and has demonstrated otherwise acceptable physical fitness, I would have the discussion that testing may or may not offer any concrete insights into the safety of diving, and if they felt the testing was absolutely required I would be happy to order it. If the individual understood that testing cannot absolutely remove all risk, that in general the risks are likely fairly low for physically fit individuals, and they wanted to dive without additional testing I would agree with their own personal risk assessment. This would be a fairly in depth conversation though, not a 5 minute fleeting “oh hey by the way…” on the way out the door.
Understood, and, PFT and CT are looking at different things as you know. Air trapping that's detectable on CT may not be on PFT. Peter Lindholm gave a nice presentation at UHMS this year on this subject and called out the benefit of doing inspiratory and expiratory CT when looking for air trapping.I don’t believe there is any way we can fully exclude air trapping.
CT scans are commly referred used for such exams, but studies have noted that what appears to be air trapping on CT does not always equate to findings on a pulmonary function test.
Additionally some studies have noted that what appear to be healthy individuals frequently have some air trapping noted on CT scan. The same study also noted that single inspiratory view CTs may not be sufficient and postulate that both inspriatory and expiratory scans are required. This causes me to question if CT findings are reliable enough to predict who can and cannot safely dive
Expiratory CT scan in patients with normal inspiratory CT scan: a finding of obliterative bronchiolitis and other causes of bronchiolar obstruction - PMC
Expiratory CT scan is usually obtained as supplement to normal inspiratory CT scan to recognize air-trapping, which is expression of small airways obstruction. In some patients the air-trapping may be the only sign of an early-stage small airways ...
Finally an article from military medicine discussed the usefullness of PFT and chest CT in determining who may be at risk for barotrauma from diving. The discussion is from case series and discusses returning to diving after barotrauma related to diving without violating dive procedures (so an “unexplained” barotrauma)
The weakness of this article, and of many studies related to risk of diving, is the lack of a true denominator. Thousands of divers go underwater each day and nearly all of them do just fine. Undoubtedly a good percentage of them have some degree of COPD, Asthma, or other potential causes of air trapping in the lungs. What percentage would you guess have air trapping in their CT or less than ideal PFTs but still continue to dive safely?
That becomes the rub of my trepidation with screening physicals. We don’t have a crystal ball, and while the extreme cases certainly offer easier insights; if you are not physically fit enough to walk a flight of stairs, you’re likely not physically fit enough to dive, for individuals who feel healthy it becomes much more difficult to predict the future, good or bad.
To answer your final question - if the individual in question is several years out from his injury/illness and has demonstrated otherwise acceptable physical fitness, I would have the discussion that testing may or may not offer any concrete insights into the safety of diving, and if they felt the testing was absolutely required I would be happy to order it. If the individual understood that testing cannot absolutely remove all risk, that in general the risks are likely fairly low for physically fit individuals, and they wanted to dive without additional testing I would agree with their own personal risk assessment. This would be a fairly in depth conversation though, not a 5 minute fleeting “oh hey by the way…” on the way out the door.
I recall you having made a similar point about the denominator before. Yes, maybe there are people with COPD who dive without getting gas embolisms, to use your example. That doesn't mean that we should give people with COPD blanket clearance to dive. It means that we recommend that they don't dive because the risk for barotrauma is unacceptably high, and if they insist on diving anyway, we educate them as best we can about the risks of doing so. I don't know many people who would sign them off as fit to dive though. You may be one, were you ever in a position to attest to fitness to dive, and that's your prerogative.
Getting back to the OP's case: we don't know much here aside from the fact that there was likely an abscess or empyema and he probably had part of a lung removed, but even that is secondhand information from a well-intentioned lay person. Would you really say he is fit to dive, knowing only what has been posted here? If he presented to you, would you scan him?
Best regards,
DDM
My question is what degree of evidence would you need to clear him?
I imagine that we both acknowledge that a 2V cxr isnt near sensitive enough.
The better question is, what does a CT of the chest, even with inspiratory and expiratory views, actually prove? Does the lack of air trapping on the CT guarantee that a diver is safe? Does air trapping 100% correlate to future barotrauma if diving? Again I’d safely wager we would both say no to those statements.
If the answer to air trapping is it depends, then to what degree does it depend? Is a little trapping still fairly safe? Is a large ammount of trapping exceedingly dangerous? What do we say about patients who are asymptomatic but with evidence of mild trapping? How about those who have occasional symptoms of mild persistent asthma but a clear scan?
So now we are in this very nebulous area where there really isn’t any solid data or evidence to make a recommendation. I have never seen any reliable data to say what degree of air trapping on a CT correlates to risk when diving. Is any clinical assessment tool beyond “do you feel okay” when exercising moderately a good predictor of the risk of injury when diving. To date I have not seen one (admittedly not my area of practice), but I’d certainly be open to one that has evidence to support it.
So, if this patient, or any patient for that matter, wanted my advice on if they were safe to dive (or other potentially strenuous physical activity) we would spend several minutes discussing their cardiovascular health. We would talk about the available testing modalities that could potentially offer insight to their risk, acknowledging that none of these tests are a crystal ball. We would also discuss there is always danger of incidental findings when you perform a test, especially a screening test, and via shared decision making we would decide if the patient wanted the test. If they wanted the testing because it would make the patient feel better about their decision I would order it. If the patient was of the opinion that they felt healthy enough to dive, and there were no obvious red flags to the patients perception of their health, then yes I would likely clear them to dive without any additional testing.
I think the issue with the denominator is imporntant. While many people with obstructive lung disease of some form or another are not healthy enough for many physical activities, to include scuba diving, a non trivial percentage of people with lung disease are healthy enough to dive and appear to do so fairly safely, as we do not hear about dive associated embolisms or pneumothorax on a daily basis. Without knowing this true number it is very possible to overestimate the risk of injury to someone that appears healthy but has a pulmonary diagnosis.
So as long a someone understands there is risk associated with diving, and that some disease processes potentially add some unknown additional degree of risk, I believe that the individual should be allowed to make that risk valuation for themselves. One person may love diving. It may be their primary mode of stress relief and their main source of social interaction. Removing that may be far more dangerous to their mental health than the risk of diving itself and therefore acceptable to the person.
OTOH someone may decide that any additional risk at all is not acceptable to just look at some fish they could see on the internet and chose not to dive.
Is either person wrong for that decision? I’d argue no. It’s not my job as a clinician to make that decision for most people unless they truly cannot understand the risk they want to undertake and I have very strong evidence that the risks they want to undertake outweigh the benefits.
What do you mean by the "danger of incidental findings"? It sounds like you're advocating for erring on the side of not imaging so as not to see something else that could be adverse.
Enough to rule out air trapping that can be discovered with existing technology, and THEN we'd have a conversation about the limits of the technology and the risk of diving.
Best regards,
DDM
OP
ElizaDoolittle
Registered
Thanks a lot everyone! I've read carefully all you've written.
Oh gosh, I'm getting scared about this. I mean, although what you write sounds very technical to ignoramuses like me, I'm trying to understand it all, and it certainly looks like no one can be really sure of what the risks will be. I understand that the most important thing here would be to try to figure out if air trapping is happening, isn't it? To me, the most complicated thing would be to find a doctor who knows about the physics of diving.
What I know for sure is that he had pneumonia and was sick for many months, he got a ball of pus that had to be removed, and at the same time they removed it, they removed part of the lung.
If I've got it right, there are two issues here: whether he can tolerate underwater exercise and whether there's some extra risk associated with the presence of air trapped inside or by the lungs, isn't it so? As for the first of the two, my impression is that he can. To me, diving is a very mild form of exercise; the most tiring part of it is lugging all the equipment to the boat. Of course, it might be more difficult for him. He's not the sporty type, but I know he tries to be fit and walks for one hour every day, he goes to the gym twice a week (what type of exercise he does there, I have no idea). I've seen him trot to catch the train, though very short distances (and I have no idea whether he couldn't run faster or he was waiting for me, who am not the fastest woman alive). But -this is my impression- when he told me about his illness, he gave the impression that he's got limitations how he didn't use to have. He didn't give examples, but the way he told the story, I think that's what he feels.
I hadn't thought of this before, and I'm almost ashamed to type this, but he had a son three years after the operation. I don't know whether that provides a measure of how much he can exert himself.
What I don't know is whether he was told not to dive by a doctor back when the operation took place, or that's the way he feels without having researched into it. From what I've been told, he got really gloomy and asocial for several years after all of this happened to him, and it's only very recently he's started to be himself again, so he may have been in a pessimistic mood and thought that he's more of an invalid than he really is. Of course, this is what I would ask to him first of all, but as I said, I'd rather not bring this subject up if I don't think there's a possibility of his diving again, so as not to remind him that there are things he loved to do but can't do anymore.
Most of the time, we're in the south of England. But we spend long spells abroad, not necessarily in the same place; actually, we met in south Spain (which is where I usually dive, together with Italy, and where he used to dive). The easiest thing would possibly be to see a doctor in London.
Oh gosh, I'm getting scared about this. I mean, although what you write sounds very technical to ignoramuses like me, I'm trying to understand it all, and it certainly looks like no one can be really sure of what the risks will be. I understand that the most important thing here would be to try to figure out if air trapping is happening, isn't it? To me, the most complicated thing would be to find a doctor who knows about the physics of diving.
What I know for sure is that he had pneumonia and was sick for many months, he got a ball of pus that had to be removed, and at the same time they removed it, they removed part of the lung.
If I've got it right, there are two issues here: whether he can tolerate underwater exercise and whether there's some extra risk associated with the presence of air trapped inside or by the lungs, isn't it so? As for the first of the two, my impression is that he can. To me, diving is a very mild form of exercise; the most tiring part of it is lugging all the equipment to the boat. Of course, it might be more difficult for him. He's not the sporty type, but I know he tries to be fit and walks for one hour every day, he goes to the gym twice a week (what type of exercise he does there, I have no idea). I've seen him trot to catch the train, though very short distances (and I have no idea whether he couldn't run faster or he was waiting for me, who am not the fastest woman alive). But -this is my impression- when he told me about his illness, he gave the impression that he's got limitations how he didn't use to have. He didn't give examples, but the way he told the story, I think that's what he feels.
I hadn't thought of this before, and I'm almost ashamed to type this, but he had a son three years after the operation. I don't know whether that provides a measure of how much he can exert himself.
What I don't know is whether he was told not to dive by a doctor back when the operation took place, or that's the way he feels without having researched into it. From what I've been told, he got really gloomy and asocial for several years after all of this happened to him, and it's only very recently he's started to be himself again, so he may have been in a pessimistic mood and thought that he's more of an invalid than he really is. Of course, this is what I would ask to him first of all, but as I said, I'd rather not bring this subject up if I don't think there's a possibility of his diving again, so as not to remind him that there are things he loved to do but can't do anymore.
Most of the time, we're in the south of England. But we spend long spells abroad, not necessarily in the same place; actually, we met in south Spain (which is where I usually dive, together with Italy, and where he used to dive). The easiest thing would possibly be to see a doctor in London.
Sorry about the tech talk... yes, given the information you've provided, air trapping and exercise tolerance would be the two biggest factors in whether he's fit to dive.
We can't know for sure what all the risks are, but your loved one can certainly engage a UKDMC diving medical referee who can evaluate him in person, order any testing necessary, and discuss those risks with him based on his medical history. It may well be that he can return to diving.
Best regards,
DDM
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