Article: Diving and Immersion Pulmonary Edema

[Dr Simon Mitchell]

Hello,

There is an excellent contemporary paper we published in DHM (2019) written by Peter Wilmshurst (who first reported immersion pulmonary oedema) available on pubmed central:

Simon M

 

[Angelo Farina]

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

In September I had major abdominal surgery, which required intubation for several hours. At extubation I suffered of the problem: I could not inhale more than 0.6 liters due to oedema.
The therapy was a pulmonary exercise employing a 1/2" silicon hose inserted in a plastic bottle with 15 cm of physiological solution. I had to inhale freely and slowly, and exhale through the pipe, making the air to bubble inside the liquid. This creates a respiratory cycle with a significant average positive pressure, which helped to "push away" blood from my lungs. Repeating this exercise a number of times, in less than 24h the oedema was eliminated. After each exercise session (6 to 10 exhalation) I perceived the immediate increase of the volume of air which I was able to inhale.
After this first-hand experience, I now think that our regulators should be tuned for minimal inhalation effort, and some larger exhalation effort, so the average pressure during the respiratory cycle remains significantly positive.
I do not think it is a good idea to employ regulators with minimal exhale effort, as keeping a positive pressure in your lungs is healthy.

 

[clownfishsydney]

Hello,

There is an excellent contemporary paper we published in DHM (2019) written by Peter Wilmshurst (who first reported immersion pulmonary oedema) available on pubmed central:

Simon M

Another paper is Scuba divers' pulmonary oedema: recurrences and fatalities by Dr Carl Edmonds, John Lippmann, Dr Sarah Lockley and Dr Darren Wolfers in Diving and Hyperbaric Medicine Volume 42 No 1 March 2012. Copy available at my web site via this page, see towards the bottom: Michael McFadyen's Scuba Diving Web Site.

Also on that page is a detailed description of a dive (that I was also on) that led to the death of a close friend from IPE. I think this is also worth reading. I am now certain that some other people who died in diving accidents in Sydney in 1990s and 2000s were probably IPE, not drowning as reported.