non-cardiogenic pulmonary edema

[TSandM]

Since the problem with pulmonary edema is fluid backed up between the right ventricle and the left atrium, anything that allows the left side of the heart to pump fluid forward more easily may help relieve the edema. Nitro is a peripheral vasodilator, and lowers peripheral vascular resistance, thus improving forward flow. It may actually not be as helpful with IPE, since the problem is pulmonary, rather than peripheral vascular resistance. But diuretics like Lasix, which reduce central venous pressure and therefore preload, are probably NOT going to be very helpful in IPE, since reducing preload is going to decrease total cardiac output unless you do something about the pulmonary vascular resistance at the same time.

I think the first thing I'd reach for with a sick IPE patient, is BIPAP on 100% O2; the oxygen will help relax pulmonary vessels, and the pressure will help combat the drive to fluid extravasation from overloaded vessels.

 

[Cave Diver]

Since the problem with pulmonary edema is fluid backed up between the right ventricle and the left atrium, anything that allows the left side of the heart to pump fluid forward more easily may help relieve the edema. Nitro is a peripheral vasodilator, and lowers peripheral vascular resistance, thus improving forward flow. It may actually not be as helpful with IPE, since the problem is pulmonary, rather than peripheral vascular resistance. But diuretics like Lasix, which reduce central venous pressure and therefore preload, are probably NOT going to be very helpful in IPE, since reducing preload is going to decrease total cardiac output unless you do something about the pulmonary vascular resistance at the same time.

I think the first thing I'd reach for with a sick IPE patient, is BIPAP on 100% O2; the oxygen will help relax pulmonary vessels, and the pressure will help combat the drive to fluid extravasation from overloaded vessels.

So is that something you'd recommend a lay person have in their kit?

 

[Peter Guy]

TSandM -- want to translate that into English for us poor ignorant folk?

 

[DocVikingo]

So is that something you'd recommend a lay person have in their kit?

Hi Cave Diver,

Let me open by indicating that SIPE is in general a very uncommon event, and even more so in the healthy diver.

BIPAP devices are not inexpensive. Their use typically is ordered by a physician. Although one does not need a prescription to purchase one, their application without proper training is highly questionable.

Moreover, lay individuals may have difficulty in arriving at a correct differential diagnosis (which could include such dive-related conditions as DCI, lung expansion injury, salt water aspiration). Given this, the untrained individual could end up doing more harm than good with BIPAP.

Regards,

DocVikingo

 

[Cave Diver]

Hi Cave Diver,

Let me open by indicating that SIPE is in general a very uncommon event, and even more so in the healthy diver.

BIPAP devices are not inexpensive. Their use typically is ordered by a physician. Although one does not need a prescription to purchase one, their application without proper training is highly questionable.

Moreover, lay individuals may have difficulty in arriving at a correct differential diagnosis (which could include such dive-related conditions as DCI, lung expansion injury, salt water aspiration). Given this, the untrained individual could end up doing more harm than good with BIPAP.

Regards,

DocVikingo

Doc,

Thanks for the response. I should have been more clear in my question. I was referring more to the discussion of the nitro tablets.

Also, in lieu of a BIPAP I was thinking more of just an oxygen setup like the Rescuean that allows you to use a scuba tank to provide (slight) positive pressure via an oral/nasal mask.

Any downsides to either of those thoughts?

 

[DocVikingo]

Doc, Thanks for the response. I should have been more clear in my question. I was referring more to the discussion of the nitro tablets. Also, in lieu of a BIPAP I was thinking more of just an oxygen setup like the Rescuean that allows you to use a scuba tank to provide (slight) positive pressure via an oral/nasal mask. Any downsides to either of those thoughts?

Hey Cave Diver,

Well, the nitro tabs will take up a whole lot less room in your kit, that's for sure ; )

RE the Rescuean, provided that one has the diagnosis correct and knows how to properly use the device, it could be of benefit until fully-equipped, expert care takes over.

RE the nitro tabs. To the best of my knowledge, this drug has not yet been tested
in the treatment of IPE (although DDM's lab reportedly is looking at another nitric oxide enhancer/liberator). To my mind, it's conjectural whether nitro might be of benefit given that the opposition to forward vascular flow in SIPE may or may not lessen in response to the relaxation of peripheral vessels brought about by nitro.

Finally, nitro is not a drug to be taken or administered by an untrained lay individual.

Regards,

DocVikingo

This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual and should not be construed as such.

 

[TSandM]

Nitro has nasty effects in someone whose problem may be other . . . my comments were aimed at the medical professional who has access to blood pressure monitoring equipment and oxygen saturation monitors.

The diagnosis of IPE has to be sorted out from other causes of pulmonary edema which are far more common (heart attack among them). Plain oxygen, by nasal prongs or mask, is almost entirely without risk and should be instituted in anyone complaining of breathing problems after a dive. Activation of EMS should be next; more advanced therapies should away trained personnel and appropriate data-gathering devices.

 

[DocVikingo]

Plain oxygen, by nasal prongs or mask, is almost entirely without risk and should be instituted in anyone complaining of breathing problems after a dive.

For purposes of clarity to the lay audience, 100% 02 is the immediate treatment recommendation for nearly all divers complaining of breathing problems post-dive.

Under these circumstances, delivery of 02 via mask ideally is done with a demand system, with a constant-flow system being used if demand is not available. Delivery via nasal prongs is the least effective regarding 02 concentration, but highly unlikely to cause any complications.

Positive-pressure ventilation, such as may be provided by BIPAP discussed in posts above, is another matter. Such systems are not almost entirely without risk in all divers with pulmonary compromise. For example, they could pose very serious risk for divers with a lung overexpansion injury or a pneumothorax.

Regards,

DocVikingo

This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual and should not be construed as such.

 

[Duke Dive Medicine]

Doc,
Also, in lieu of a BIPAP I was thinking more of just an oxygen setup like the Rescuean that allows you to use a scuba tank to provide (slight) positive pressure via an oral/nasal mask.

Any downsides to either of those thoughts?

John,
The rescuean doesn't give positive pressure, it's basically just an adapter to go from a high pO2 deco mix or O2 deco bottle to a medical O2 mask or bag valve mask. It's just fine to use on any diving casualty if the user is properly trained and there's no medical O2 available.

 

[denisegg]

It sounds like he had what I just experienced in the Cayman Islands. I am a physician and experienced SOB at 15 feet while decompressing after diving the wall. Was at 80 feet for a short time had been diving all week without any problems.I did not swallow any water did not have a panic attack I have been diving on and off for 30 years, I was sucking very hard to breath probably a faulty gauge and developed negative pressure pulmonary edema/ We see it in the operating room in young very fit patients that can generate very high negative pressure against a closed glottis I spent 2 days in ICU in Caymans By the way the health care there is excellent but they call all these incidents :non fatal drowning .

I'm not sure I am understanding this. What is the difference in negative pressure pulmonary edema and IPE?