Timeframe for diving post covid +

[kinoons]

Nobody in the present day is going to blindly randomize a post-COVID diver with (albeit small) potential for lung pathology into a study arm that recommends diving. Based on our current knowledge, that would be completely unethical. The best we're going to get is retrospective data, which again, I hope someone takes the time to gather. It may well happen that the overall risk is low enough that the recommendations can be modified.

Best regards,
DDM

This sounds like some very poor limitations to the IRB process and medical research in general.

The facts are simple. People are diving post Covid. Lots of people. If I was to hazard a guess the overwhelming majority without any medical evaluation prior to doing so. Many are diving not knowing if they even had Covid or not.

Now if we randomized these same divers to eval or no eval the only thing to change would be the number of divers getting an eval as that would likely go up, not down from the likely very small number that currently exists.

Hell you could stipulate that the population your pulling from would be divers who wouldn’t have gotten an evaluation in the first place. Now you only have potential benefit.

It isn’t perfect, there will certianly be some selection bias, as the non healthy folks won’t chose to dive, but it’s far better evidence than “we think there might be some risk”.

The “we cannot risk harm” group are the same ones that thought masks were a parachute at the beginning of the Covid pandemic. Now we’re three years later with not a single RTC performed regarding mask wear and mostly total garbage evidence on the benefits and risks of mask wear. It’s one of the greatest failures of the pandemic.

Medical screening tests are certianly not a parachute. To justify their cost and possible non-intended adverse outcomes RTCs should be the expected level of evidence.

 

[kinoons]

Not that I'm a researcher in any sense, as someone who had to write an IRB application for truly benign stuff, you need to justify that what your doing is safe, they don't have to prove it's unsafe. If your study is trying to assert that you need xyz protocol to dive safely you can not in good conscious recommend the opposite for a control. What you need to do is show that the control is 'standard care' vs your new and better protocol. With Covid the conservative approach is 'standard care' so you can't experiment by telling a bunch of people to be 'unsafe' based on current protocols.

If you have a retrospective study that shows it IS safe to dive without xyz protocol THEN you can justify that it is safe to the IRB and conduct your study. Maybe. If they're nice.

Where was the IRB when the decision to have the suggested screening tests was adopted? (I get IRBs don’t get involved in those recommendations).

My point is that the UCSD dive medicine folks made suggestions founded on very little to zero actual data, recommendations based on a perceived risk that has not been proven. Now these recommendations are being treated as gospel.

Now if someone asks for a study to prove the gospel is golden? No that’s not safe. No one ever proved the recommendations were safe in the first place.

If there is actually no risk (which we don’t know) then any amount of testing is only harm.

I guarantee there will be at least one person who is post Covid who wants to dive. They could follow these recommendations, have a CXR that finds some nodule. That gets them a chest CT, possibly repeat CTs, perhaps a biopsy. Assuming that biopsy goes without complication (more harm) it’s likely for the module to be non-cancerous.

All of this will be done for a screening exam that had no proven benefit. All the additional time, radiation, cost, and worry will be for nothing.

Expand this to a population level, even one as relatively small as the dive community, and it is certianly possible to see more harm than good done.

This isn’t to say that testing isn’t appropriate for an individual patient, but when you start to make population level recommendations there needs to be real evidence to back it up.

 

[FabletheRaven]

Where was the IRB when the decision to have the suggested screening tests was adopted? (I get IRBs don’t get involved in those recommendations).

My point is that the UCSD dive medicine folks made suggestions founded on very little to zero actual data, recommendations based on a perceived risk that has not been proven. Now these recommendations are being treated as gospel.

Now if someone asks for a study to prove the gospel is golden? No that’s not safe. No one ever proved the recommendations were safe in the first place.

If there is actually no risk (which we don’t know) then any amount of testing is only harm.

I guarantee there will be at least one person who is post Covid who wants to dive. They could follow these recommendations, have a CXR that finds some nodule. That gets them a chest CT, possibly repeat CTs, perhaps a biopsy. Assuming that biopsy goes without complication (more harm) it’s likely for the module to be non-cancerous.

All of this will be done for a screening exam that had no proven benefit. All the additional time, radiation, cost, and worry will be for nothing.

Expand this to a population level, even one as relatively small as the dive community, and it is certianly possible to see more harm than good done.

This isn’t to say that testing isn’t appropriate for an individual patient, but when you start to make population level recommendations there needs to be real evidence to back it up.

Welcome to cover your ass medicine. If you ask a doctor and they say you're good to dive, but there isn't some kind of work up or evidence to back him up, and you get hurt, he's looking at a lawsuit. This is why people get the CT scan and the biopsy etc. Unfortunately until there is research to back up the less conservative plan your doctor is going out on a limb to clear you. This is waaaay more true when it comes to a large organization that has to generalize guidelines. This is why you needs to ask your personal physician if it's safe for you to dive.

 

[FabletheRaven]

Also I get that the IRB process is a pain in the ass, but with a very sketchy history of human experimentation it's completely necessary. In this case, if I sat on a review board and you pitched a study where some people get medical clearance and some don't NO WAY I'd approve it.

 

[kinoons]

Welcome to cover your ass medicine. If you ask a doctor and they say you're good to dive, but there isn't some kind of work up or evidence to back him up, and you get hurt, he's looking at a lawsuit. This is why people get the CT scan and the biopsy etc. Unfortunately until there is research to back up the less conservative plan your doctor is going out on a limb to clear you. This is waaaay more true when it comes to a large organization that has to generalize guidelines. This is why you needs to ask your personal physician if it's safe for you to dive.

I again disagree. I work in emergency medicine. By definition my entire day is a balance of risks and benefits; known and unknown hazards.

For some patients I push them very strongly to testing or treatment because the risks of the suspected illness far outweigh the risks or harms of the proposed testing /treatments.

On the other hand I frequently have patients with what appear to be fairly benign symptoms, reassuring test results, or non-descript symptoms that do not easily suggest a course of care.

All day I have the discussion of risks and benefits as well as shared decision making about the possible courses of action. Even more so when there isn’t a clear course of care.

In absence of additional evidence if a healthy young adult came to me asking if they were safe to dive two weeks after fully recovering from a minimally or asymptomatic course of Covid I would have the discussion with them that some experts suggest the testing as listed by UCSD, but this is based on professional opinion alone with no RTC or similar level of evidence to back it up. If this person felt well enough that they wanted to forego the testing and my exam/VS, etc were all reassuring I wouldn’t hesitate to clear them to dive.

Am I worried that I’d get sued if that diver had a bad outcome? No. That diver and I had the discussion and came to an agreeable course of action.

With that in mind, anyone can sue anyone for anything. I’ve been through it before, and I’ll likely go through it again.

 

[duke dive medicine]

In absence of additional evidence if a healthy young adult came to me asking if they were safe to dive two weeks after fully recovering from a minimally or asymptomatic course of Covid I would have the discussion with them that some experts suggest the testing as listed by UCSD, but this is based on professional opinion alone with no RTC or similar level of evidence to back it up. If this person felt well enough that they wanted to forego the testing and my exam/VS, etc were all reassuring I wouldn’t hesitate to clear them to dive.

Thank you for this articulate response, which given your background is also professional opinion IMO. As an EM provider, no doubt you have seen the gamut of COVID symptoms and there are divers who you would NOT clear to dive post-COVID. I'd be interested to hear where your line would be, so to speak.

Best regards,
DDM

 

[kinoons]

Thank you for this articulate response, which given your background is also professional opinion IMO. As an EM provider, no doubt you have seen the gamut of COVID symptoms and there are divers who you would NOT clear to dive post-COVID. I'd be interested to hear where your line would be, so to speak.

Best regards,
DDM

my first draft of a reply was a rather long post delineating multiple types of pts (asymptomatic vs mild illness vs progressively worsening illness up to ICU stays, who is symptomatic vs who isn’t) that could realistically be distilled down to the following.

I agree with categories 0, 2, and 3 of the UCSD recommendations. I also agree with the statement that symptomatic folks should not dive. These would have fallen in line with any return to scuba recommendations for a moderate to severe infection/illness prior to Covid, yes?

Where UCSD and I differ is category 1. Prior to Covid would you have recommended screening exams for a patient who had a viral URI or influenza with minimal symptoms, has fully recovered, and wants to now dive? I would have not.

Although I will admit I am coming at this from the point of view of a recreational diver. Was it, prior to Covid, standard of care to chest x-ray a commercial diver after a viral URI or influenza and subsequent complete recovery?

 

[duke dive medicine]

my first draft of a reply was a rather long post delineating multiple types of pts (asymptomatic vs mild illness vs progressively worsening illness up to ICU stays, who is symptomatic vs who isn’t) that could realistically be distilled down to the following.

I agree with categories 0, 2, and 3 of the UCSD recommendations. I also agree with the statement that symptomatic folks should not dive. These would have fallen in line with any return to scuba recommendations for a moderate to severe infection/illness prior to Covid, yes?

Where UCSD and I differ is category 1. Prior to Covid would you have recommended screening exams for a patient who had a viral URI or influenza with minimal symptoms, has fully recovered, and wants to now dive? I would have not.

Although I will admit I am coming at this from the point of view of a recreational diver. Was it, prior to Covid, standard of care to chest x-ray a commercial diver after a viral URI or influenza and subsequent complete recovery?

Thanks for your perspective, and great questions. For run-of-the-mill viral URI or influenza pre or even post-COVID, I think most providers would not give it a second thought and would consider getting a chest x-ray prior to returning to diving, even for commercial or military divers, as unnecessary. I think COVID was a game-changer, and we're still learning to stratify the risks based on symptom/disease severity. Studies like this one lend credence to the idea that lung damage can occur even after mild disease, though the ambulatory group in this study may not reflect the demographics of healthy divers. Still, the findings are significant. In assessing fitness to dive, what risk would a provider be willing to tolerate that a diver who had mild COVID could have air trapping after recovering from the acute phase?

Best regards,
DDM

 

[kinoons]

Thanks for your perspective, and great questions. For run-of-the-mill viral URI or influenza pre or even post-COVID, I think most providers would not give it a second thought and would consider getting a chest x-ray prior to returning to diving, even for commercial or military divers, as unnecessary. I think COVID was a game-changer, and we're still learning to stratify the risks based on symptom/disease severity. Studies like this one lend credence to the idea that lung damage can occur even after mild disease, though the ambulatory group in this study may not reflect the demographics of healthy divers. Still, the findings are significant. In assessing fitness to dive, what risk would a provider be willing to tolerate that a diver who had mild COVID could have air trapping after recovering?

Best regards,
DDM

Thanks for the reply. My thoughts on the study you linked to.

As you acknowledged the study has limitations. First the subjects are still experiencing symptoms after 30 days, which isn’t the group we’re talking about, as we’re discussing fully recovered divers. Second the median age is 48, which must be considered when making recommendations that will cover all age groups. Third we have no idea if these findings on CT translate to clinically significant outcomes when diving. Additionally the study was performed early in the Covid pandemic, before delta and omicron.

my question would be what portion of patients who are still symptomatic 30 days post viral uri or influenza have air trapping on chest CT. I don’t do follow up care - what portion of pts were able to get their primary care or pulm to do a chest CT one month after an acute infection to eval why they were still short of breath prior to Covid? The presence of GGO on CT is what is being measured, is the rate of GGO post Covid different than post flu or viral uri? Is Covid actually that different, or just something we’re looking closer at?

Again, none of the above applies to the group of minimally symptomatic fully recovered divers we’re discussing.

 

[kinoons]

Also I get that the IRB process is a pain in the ass, but with a very sketchy history of human experimentation it's completely necessary. In this case, if I sat on a review board and you pitched a study where some people get medical clearance and some don't NO WAY I'd approve it.

So lets theorize a study that goes something like this...

Dive shop A located in a tropical dive location takes out four boatloads of 20 divers out each day. Two AM trips, two PM trips. Some divers may take both trips, but lets guess we're looking at 60-70 divers every day are heading out. They have made the decision that they want to dive and that they feel well enough to do so.

It is quite safe to say that 40%+ of folks in the US have had covid (that number is likely significantly higher, but its what the CDC is reporting). The CDC does acknowledge that 90%+ of kids have had covid. Think adults are really that far behind?

What was the SARS-CoV-2 seroprevalence among US adults during 2021 and 2022?

In a recent Morbidity and Mortality Weekly Report (MMWR), the United States Center for Disease Control and Prevention (U.S.-CDC) published the preliminary results of the National Health and Nutrition Examination Survey (NHANES) for August 2021–May 2022.

www.news-medical.net

COVID Data Tracker

CDC’s home for COVID-19 data. Visualizations, graphs, and data in one easy-to-use website.

covid.cdc.gov

so roughly 50% (or more) of the folks who have already self selected to go diving have had and recovered covid.

I would then postulate that it is acceptable to contact those divers a few days prior to their dive trip and attempt to enroll them in a study where the participants are randomized to dive as planned or the day prior to diving have an exam to establish their fitness for diving.

By definition the study would not be taking any participants who were initially planning to get an exam and exclude them from an exam. The dive trip is already planned. If the diver wanted an exam before the trip they would have arranged for one. (These divers who did receive an exam would be excluded from the study). This study would instead only be taking a population of divers who felt they did not need an exam prior to diving and potentially obtain one.

Even if you only got 4 or 5 folks a day to agree to be randomized it wouldn't take more than maybe a month at a few sites to obtain a few thousand participants. Follow them for several weeks and I'd bet you'd see a trend one way or another as far as the risk of covid and diving goes for those who were minimally ill and fully recovered. Dive injury rates prior to 2019 could be used as a control.

If a researcher came to your IRB with something like what I proposed above, you'd vote to not allow it?

My own WAG; 90%+ of the population has had and recovered from Covid. That means that 90%+ of divers have had and recovered from Covid. If there was some danger related to having recovered from Covid and subsequently scuba diving the community as a whole should have seen an increase in dive related illness/injuries. I am not aware of any such increase. However, I will admit that my location isn't a diving hotbed and I don't practice dive medicine for a living, so I likely wouldn't have heard of any changes in rate of injury.