Ayisha
Contributor
You can view the page at http://www.scubaboard.com/forums/content.php?r=519-Diving-and-Immersion-Pulmonary-Edema
Article: Diving and Immersion Pulmonary Edema
- Thread starter Ayisha
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Excellent and timely reminder that there is more to diving fitness than we learn in a basic scuba class.
muzikbiz22
Contributor
Great article ! Very comprehensive.
Ayisha,
Nicely done and very thorough.
There is a difference between true immersion pulmonary edema and pulmonary edema that is aggravated by, or occurs in conjunction with, immersion. True IPE is often seen in triathletes or military special operations divers whose cardiac outputs are extremely high. In these individuals, the pulmonary arteries fail to dilate sufficiently in response to the increased blood flow brought on by the combination of immersion, exercise and cold water, though as you noted, IPE has occurred in warm water as well.
Other divers with pre-existing cardiac problems may have no symptoms while on the surface, but the fluid shift brought on by immersion can overwhelm a heart that's not working as efficiently as it should, and blood can back up in the lungs, with resultant pulmonary edema. This is cardiogenic pulmonary edema that's aggravated by immersion and should be differentiated from true IPE.
Negative pressure pulmonary edema has been documented in post-surgical patients. It typically happens in young, athletic males who are extubated (have breathing tubes removed) after surgery and experience subsequent upper airway edema. Attempting to inhale through an airway that's swollen can create a negative pressure in the lungs, which can draw fluid from the pulmonary capillaries and cause pulmonary edema. I've heard rumblings of it in divers, but to my knowledge it hasn't been reported in the literature, so if you have references would you please share? We've been involved with one possible case of it in a diver and even spoke with the equipment manufacturer, but that case was confounded by other medical factors so ultimately we couldn't pin it on NPPE.
Best regards,
DDM
Nicely done and very thorough.
There is a difference between true immersion pulmonary edema and pulmonary edema that is aggravated by, or occurs in conjunction with, immersion. True IPE is often seen in triathletes or military special operations divers whose cardiac outputs are extremely high. In these individuals, the pulmonary arteries fail to dilate sufficiently in response to the increased blood flow brought on by the combination of immersion, exercise and cold water, though as you noted, IPE has occurred in warm water as well.
Other divers with pre-existing cardiac problems may have no symptoms while on the surface, but the fluid shift brought on by immersion can overwhelm a heart that's not working as efficiently as it should, and blood can back up in the lungs, with resultant pulmonary edema. This is cardiogenic pulmonary edema that's aggravated by immersion and should be differentiated from true IPE.
Negative pressure pulmonary edema has been documented in post-surgical patients. It typically happens in young, athletic males who are extubated (have breathing tubes removed) after surgery and experience subsequent upper airway edema. Attempting to inhale through an airway that's swollen can create a negative pressure in the lungs, which can draw fluid from the pulmonary capillaries and cause pulmonary edema. I've heard rumblings of it in divers, but to my knowledge it hasn't been reported in the literature, so if you have references would you please share? We've been involved with one possible case of it in a diver and even spoke with the equipment manufacturer, but that case was confounded by other medical factors so ultimately we couldn't pin it on NPPE.
Best regards,
DDM
Ayisha:
Great article. My only comment was already made eloquently by Duke Dive Medicine above. I, too, would be interested in any information you have on negative pressure pulmonary edema.
Doug
Great article. My only comment was already made eloquently by Duke Dive Medicine above. I, too, would be interested in any information you have on negative pressure pulmonary edema.
Doug
OP
Ayisha
Contributor
Hi Drs. Thank you very much for reading it and the explanations. I don't recall the distinction being made about true IPE and cardiogenic pulmonary edema other than as different theories of how it affects such varied individuals. I actually wrote the article a year ago but it didn't get published until recently, so maybe that is newer information? I know you both are on the cutting edge of this and I appreciate the info.
I am happy to share the research with you. I can send you the references and I'll sort through to get you the ones referencing NPPE.
I am happy to share the research with you. I can send you the references and I'll sort through to get you the ones referencing NPPE.
Hi Ayisha,
Another way of putting it would be that we suspect that there is a subset of people who are susceptible to immersion pulmonary edema. We know that it tends to reoccur in triathletes and combat swimmers with documented IPE (which they know as swimming induced pulmonary edema, or SIPE). Since these individuals tend to be highly fit and have few other health problems, it's relatively easy to study "pure" IPE in them. The recreational diving community is a broader demographic so it's more likely that a diver with pulmonary edema has confounding comorbidities, which make it much more difficult to predict and to tease out the exact etiology. For example, a diver (or snorkeler, for that matter) with heart issues who is not predisposed to IPE may suffer pulmonary edema simply due to fluid redistribution. Heavy work and cold water would increase the risk, but is this then IPE or cardiogenic pulmonary edema acting synergistically with immersion? A diver with heart problems who IS predisposed may also suffer pulmonary edema while immersed, so you can see where the waters could become a bit murky.
We have several ongoing studies on IPE; in fact, Dr. Moon's research assistant was pouring Pedialyte for us yesterday and wondering if a Navy SEAL could chug 2 liters of it in 30 minutes prior to immersed exercise, the rationale being that overhydration is another risk factor. Another of Dr. Moon's studies is investigating the effectiveness of sildenafil (Viagra), which was originally formulated to treat pulmonary hypertension. We're also looking to see whether there's any correlation with mitral valve regurgitation.
One of your most important points was that no matter what the cause, the field treatment for pulmonary edema is the same: high-flow O2 and immediate evacuation.
Best regards,
DDM
Another way of putting it would be that we suspect that there is a subset of people who are susceptible to immersion pulmonary edema. We know that it tends to reoccur in triathletes and combat swimmers with documented IPE (which they know as swimming induced pulmonary edema, or SIPE). Since these individuals tend to be highly fit and have few other health problems, it's relatively easy to study "pure" IPE in them. The recreational diving community is a broader demographic so it's more likely that a diver with pulmonary edema has confounding comorbidities, which make it much more difficult to predict and to tease out the exact etiology. For example, a diver (or snorkeler, for that matter) with heart issues who is not predisposed to IPE may suffer pulmonary edema simply due to fluid redistribution. Heavy work and cold water would increase the risk, but is this then IPE or cardiogenic pulmonary edema acting synergistically with immersion? A diver with heart problems who IS predisposed may also suffer pulmonary edema while immersed, so you can see where the waters could become a bit murky.
We have several ongoing studies on IPE; in fact, Dr. Moon's research assistant was pouring Pedialyte for us yesterday and wondering if a Navy SEAL could chug 2 liters of it in 30 minutes prior to immersed exercise, the rationale being that overhydration is another risk factor. Another of Dr. Moon's studies is investigating the effectiveness of sildenafil (Viagra), which was originally formulated to treat pulmonary hypertension. We're also looking to see whether there's any correlation with mitral valve regurgitation.
One of your most important points was that no matter what the cause, the field treatment for pulmonary edema is the same: high-flow O2 and immediate evacuation.
Best regards,
DDM
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pidgiepoo
Contributor
great info...my 63 year old husband got IPE while diving in Cancun... cold water.. deep, high exertion dive. He ended up in ER with a PO2 of 49 and then went to ICU for 4 days to be treated with diuretics, steroids, antibiotics, and CPAP. Worked enough to get us home so he could be followed up with Pulmonary Dept at OSU hospital. He's dove since and hasn't had any problems. He was recommended for the Duke U study, but not specifically the IPE part. I wonder if there is some way we could keep in touch with Duke to follow their study results/recommendations? Thanks again for the information in this article.
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GOLDENCORPS86
Registered
Great... Thank you for sharing it is very informative.
OP
Ayisha
Contributor
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