Updated case review on immersion pulmonary edema

[Duke Dive Medicine]

Dr. Dionne Peacher and colleagues have published a review of almost 300 cases of immersion pulmonary edema.

anesthesiology.duke.edu/?p=830007

Immersion Pulmonary Edema and Comorbidities: Case Series and Update... - PubMed - NCBI

 

[muzikbiz22]

Thanks for the update. IPE has always fascinated me for some reason. Th results here are not surprising, makes total sense.

 

[dreamdive]

Thank you for making this available. I can tell you however, I had a negative cardiac work-up after my incidence 2 years ago. I did not then and currently have no medical conditions. So there are a number of divers who for "no apparent" reason might experience IPE.
Some authorities recommend the cesation of diving activity after an event of IPE to prevent a possible recurrence. I will tell you that I have continued diving and went deeper and longer, gratefully without incidence. Can it happen again? Absolutely. BUT: what those who have not been aflicted must realize is that it could happen to anyone, including them. It happened to me, a very fit, healthy, normal weight, diver on a recreational dive (not one of my deep trimix cave dives) in warm water.

The only thing that I can think of that may have been a precipitating factor was 1. Overhydration prior to diving 2. A borrowed wetsuit that was a bit too tight.

I applaud Duke Medicine for researching this phenomena. One, that appears more common than previously appreciated. Thanks to the dedicated physicians and scientists, we gain the valuable insights needed to formulate a preventative course of action.

If possible and more practical for us divers would be now to get recommendations from Duke or DAN as to how to 1. recognize IPE, 2. what to do underwater with a buddy with potential IPE, 3. how to deal with IPE at the surface, etc.

Thank you Duke!

Claudia Roussos MD

 

[tech_diver]

Perhaps more of our medicos can chime in on this but....

The study cites 72 per cent of the group as having one of many comorbidities. But if we grab a random group of Americans in that age group, (49 years old plus or minus 9 years) isn't that a similar percentage as the group affected by IPE? Obesity is just one of the conditions they list. Doesn't that alone affect non IPE people in high percentages? If we add hypertension, asthma and a few others, couldn't we get over 70 per cent of the general population as easily as a population of people affected by IPE?

Maybe some of our scuba docs can tell us a little more about what the numbers in this study tell us.

 

[Duke Dive Medicine]

@ Claudia, thanks for the kind words. Dr. Peacher and company are a fantastic team and have broken a lot of ground under Dr. Moon's guidance.

One of the subtle things about IPE is that there appear to be two general categories. The first occurs in otherwise healthy individuals who typically have higher-than-normal cardiac outputs, e.g. triathletes and combat swimmers. Absent other comorbidities, their pulmonary edema can likely be attributed to "pure" IPE, that is, their cardiac output increases significantly with exercise, in the setting of the fluid redistribution that occurs with immersion. Their pulmonary arteries fail to dilate sufficiently to compensate for this, and the result is pulmonary hypertension and pulmonary edema. The exact mechanism for this is still under investigation but it's thought that there is a genetic component.

The other general category occurs in the setting of identifiable comorbidities like hypertension. In these cases, the addition of immersion with concomitant fluid shift is probably the proverbial straw on the camel's back. Since recreational divers represent a wider variety of the population, they vary widely in level of physical conditioning and are more likely to have underlying health conditions.

Claudia, if Dr. Peacher and colleagues had studied you, you would have likely fallen into the 25-odd percent who had an occurrence of IPE with no identifiable health condition. Overhydration may well have been a factor, but it's also possible that your pulmonary arteries don't dilate sufficiently when you're immersed. I'm sure Dr. Moon would be happy to Swann you

In their conclusion, Peacher et al summarize: "Cardiopulmonary disease may be a common predisposing factor in immersion pulmonary edema in the recreational swimming/diving population, while pulmonary hypertension due to extreme exertion may be more important in military cases."

Best regards,
DDM

 

[dreamdive]

"Claudia, if Dr. Peacher and colleagues had studied you, you would have likely fallen into the 25-odd percent who had an occurrence of IPE with no identifiable health condition. Overhydration may well have been a factor, but it's also possible that your pulmonary arteries don't dilate sufficiently when you're immersed. I'm sure Dr. Moon would be happy to Swann you

"

Oh, Dr. Moon offered but I am too chicken for that !!

Something else that I was thinking of and may not be for discussion on a forum but, I was diving a unit with back-mounted counterlungs. As you already know, that makes for greater effort on inspiration vs. expiration. I currently diving a front-mounted CL and have noticed improved WOB particularly at depth whereas others have not noted a difference with their BMCL units. Maybe, the negative pressure generation during inspiration made me more susceptiple, as well. Just wondering..... I don't know if it is worth tracking CCR divers with IPE and what units they were diving.

Anyway, thank you!

Claudia

 

[Duke Dive Medicine]

That's actually an interesting question - we've talked about it here in the clinic and the conclusion was that in a properly functioning CCR, a back-mounted counterlung would not produce enough negative pressure to induce pulmonary edema.

Best regards,
DDM

 

[muzikbiz22]

That's actually an interesting question - we've talked about it here in the clinic and the conclusion was that in a properly functioning CCR, a back-mounted counterlung would not produce enough negative pressure to induce pulmonary edema.

Best regards,
DDM

This is refreshing, as I have often thought about IPE with regards to CCR's.

 

[Duke Dive Medicine]

If possible and more practical for us divers would be now to get recommendations from Duke or DAN as to how to 1. recognize IPE, 2. what to do underwater with a buddy with potential IPE, 3. how to deal with IPE at the surface, etc.
Claudia Roussos MD

Claudia,

It can be difficult to differentiate IPE from other respiratory issues in the field. Symptoms could include difficulty breathing, rapid breathing, productive cough (possibly with the classic pink frothy sputum but not necessarily), and acute decompensation up to cardiorespiratory arrest. First aid would begin with immediate rescue. Removing a diver from the water may be enough to allow for recovery if the symptoms are minor, but could be problematic in a diver with a decompression obligation. Give O2 on the surface, place the diver in position of comfort (Fowler's would probably be appropriate in a conscious diver) and provide a warm environment. Escalate interventions as needed, and evacuate to an ED. If a diver has a history of IPE he/she is at increased risk of reoccurrence, and the severity of one incident is not a good predictor of the severity of future incidents.

Best,
DDM

 

[dreamdive]

Claudia,

It can be difficult to differentiate IPE from other respiratory issues in the field. Symptoms could include difficulty breathing, rapid breathing, productive cough (possibly with the classic pink frothy sputum but not necessarily), and acute decompensation up to cardiorespiratory arrest. First aid would begin with immediate rescue. Removing a diver from the water may be enough to allow for recovery if the symptoms are minor, but could be problematic in a diver with a decompression obligation. Give O2 on the surface, place the diver in position of comfort (Fowler's would probably be appropriate in a conscious diver) and provide a warm environment. Escalate interventions as needed, and evacuate to an ED. If a diver has a history of IPE he/she is at increased risk of reoccurrence, and the severity of one incident is not a good predictor of the severity of future incidents.

Best,
DDM

Thank You DDM.

I agree that it may be difficult to differentiate IPE from other respiratory symptoms. However, there are some important differences that may help the affected diver identify IPE, such as

· new and sudden onset of coughing.
· Expectorate having metallic/bloody taste
· Noticing new onset wheezing
· With the above, increased difficulty breathing etc.

Perhaps the other thing to stress is the importance of oxygen/breathing an enriched mix. There have been unverified reports of people dying at the surface with IPE and air (21%) in their tanks. Considering a lot of divers diving nitrox, perhaps one recommendation could be to continue breathing enriched air until 100% can be delivered on the boat. For those technical divers, we usually carry a richer mix and on CCR can drive the PO2 higher.

I understand if DDM and DAN may not be able to make those recommendations due to legal concerns.

Thank you for keeping us updated and Happy Veterans Day!

Claudia