In Water Recompression

[PfcAJ]

But there shouldn't ever be a catastrophic type II or AGE unless you totally 'effd-up' . . . (Or else you have a gaping PFO or other atrial septal defect, or gross venous-arterial shunt you don't know about). Better find an emergency 6ATA Chamber quick for these cases.

Pretty sure Brian doesn’t have a PFO. It definitely would have been “discovered” by now.

Type 2? Psh drink some water pop an ibruprofen and walk it off

 

[LiteHedded]

Pretty sure Brian doesn’t have a PFO. It definitely would have been “discovered” by now.

Type 2? Psh drink some water pop an ibruprofen and walk it off

if i had a pfo we would FOR SURE know it by now

 

[Duke Dive Medicine]

@Schwob I agree with @LiteHedded that the move is to not get bent, however it is often out of our control even when doing everything right.

That theoretical chamber would be more "safe" because you're dry, so if you convulse then you're at least not in the water, and being dry and warm is better etc. etc.

The issue is what @Akimbo alluded to. There is a huge difference in spinning some valves and operating the chamber. That's easy. The problem is that recompression is considered medical treatment, and you have to properly diagnose, etc etc.

IWR thankfully is outside of that and pretty goes along the lines of "go to 30ft on O2, if symptoms resolve, then run the IWR procedure" for that and pray. If symptoms don't resolve, then go 10-30ft deeper depending on your beliefs and repeat, then go deeper and repear until symptoms resolve then follow procedure and pray.

The key about IWR for me is that timing seems to be everything. If you are capable of getting back in the water, then you get immediate treatment and theoretically immediate relief of symptoms with a great rate of success. If I came up and got a hit at the quarry where we do training, which is just under an hour from Duke's chambers, which operate 24/7 for diving emergencies, I would STILL do IWR first because even with that proximity to Duke, it will be at least 2 hours until you get recompressed

@tbone1004, I'd like to comment and expand on a couple of things you said here if I may.

IWR is indeed a medical treatment and involves the differential diagnosis of a diving injury in the field. As @Akimbo alluded to, there are things that can look for all the world like DCI but turn out to be something completely different. We've seen it misdiagnosed on more than one occasion. One particularly memorable case was a patient who was diagnosed with AGE by an attending diving physician and received several successive hyperbaric oxygen treatments for what turned out to be an internal carotid artery dissection. If you (not just the individual you, but anyone reading) are considering IWR, it's worthwhile to spend some time objectively reflecting on your medical diagnostic skills.

The US Navy literally wrote the book on field diagnosis and treatment of DCI by individuals with limited medical training and experience. I'm quoting from Revision 7 of the Navy Diving Manual here: "Recompression in the water should be considered an option of last resort, to be used only when no recompression facility is on site, symptoms are significant and there is no prospect of reaching a recompression facility within a reasonable time frame (12-24 hours)." (Page 17-16). So the US Navy, with its cadre of trained and experienced divers, extensive collective knowledge, and experience in diving medicine, thinks that evacuating a diver to a chamber that's 12 hours away is safer than IWR. There is also literature to suggest that delays in treatment are not as harmful as was once believed. A couple of examples are linked below:

Risk factors and clinical outcome in military divers with neurological decompression sickness: influence of time to recompression. - PubMed - NCBI
How delay to recompression influences treatment and outcome in recreational divers with mild to moderate neurological decompression sickness in a r... - PubMed - NCBI

You mention going deeper than 30 feet on O2 "depending on your beliefs". There is no sanctioned IWR protocol that goes deeper than 30 feet, and for good reason. There's an entire thread on a proposed underwater treatment table 5 here: In-Water Recompression, Revisited

The disappearance of 24/7 chambers in the US is an unfortunate trend. There are some fine people (John Peters and Dr. Enoch Huang at UHMS, Dr. Bruce Derrick at Duke, Dr. Jim Chimiak at DAN, and many others) who are working on this at a national level. Specifically, the paucity of chambers available to cave divers in Florida is something that's gotten a lot of attention, here and in other threads. To my knowledge, below are the 24/7 chambers available to Florida divers. If anyone has different information, please let me know:

1. South Georgia Medical Center in Valdosta, GA
2. Springhill Medical Center in Mobile, AL
3. Undersea Oxygen Clinic in Tampa (Joe Duturi's outfit)
4. Gulf Coast Regional Medical Center in Fort Meyers
5. St. Mary's Medical Center in West Palm Beach
6. Mercy Hospital in Miami
7. Mariner's Hospital in Tavernier

I've plotted these out on a map, and there's almost no location in Florida that is further than 150 miles from a chamber as the crow (or helicopter) flies, which is about how far Duke is from the coast of North Carolina. Of course this could (and probably will) evolve over time, but at present, the situation does not justify turning to IWR over evacuation to a chamber that is within a very reasonable distance.

Best regards,
DDM

 

[tbone1004]

@Duke Dive Medicine I think I worded that poorly. Going deeper than 30ft would be done on nitrox/air/something not exceeding a 2.0 ppO2, and the interval of something between 10-30ft would be your belief. I.e. I am going in 10ft, 15ft, 30ft etc. intervals of depth. Wouldn't ever go below 30ft on O2 in the water.

I think a big disconnect we are going to end up having in these discussions is the severity of DCS that we're talking about, and the extend of IWR that we're going to do because of it.
Do I have some pain in my knee/shoulder etc which on my personally, if I get it before I get out, I'm not going to deem that worthy of going to a chamber and not just dropping back down for a bit. If I have any neuro symptoms, then yeah, get me to the chamber. If I'm already warm/dry and something comes on, then I'm going to call DAN and see how quick I can get to the chamber, and depending on how I'm feeling, sort it out from there.

me personally, cave centric, and not advocating obviously
If I can drop down to 20ft and my symptoms resolve *which they have twice before*, I'll hang out for 30mins, go up to 10ft, and hang out as long as I am warm/comfortable/have available O2. Get to the surface, do a surface deco for at least 10-15 mins while I shed all of my gear before I get out of the water, and then hop on O2 for at least a half hour. I have had to do that twice, once from an improper fitting harness in my right shoulder, the other in my knee from being dumb and slipping on a step and landing on it wrong *how I got a bubble in that same knee during the FAD study at Duke actually but several years after the fact*. Symptoms resolved in those instances immediately after I stabilized at depth, and I felt fine once I got out. That to me isn't worth the expense/hassle of going into the chamber for 6 hours. That would be a do as I say not as I do with any students obviously and they'd be booking it to the chamber, but not what I'd personally do.

Musculoskeletal or skin? If I'm in the water, I'm more than likely going back down. I have the O2 and I'm already in the water. No real risk in doing that. If I'm out and dry, it depends on how bad it is and I'll make that call myself
Any neuro or pulmonary symptoms? no way I'm getting back in the water. Surface O2 all the way to the chamber for that guy

My buddies or anyone around me gets to make their own decisions. I make sure that I have all the gear and gas to do Pyle's IWR table, and if they feel comfortable doing it, I'll support them in any and every way that I can.

 

[Duke Dive Medicine]

@Duke Dive Medicine I think I worded that poorly. Going deeper than 30ft would be done on nitrox/air/something not exceeding a 2.0 ppO2, and the interval of something between 10-30ft would be your belief. I.e. I am going in 10ft, 15ft, 30ft etc. intervals of depth. Wouldn't ever go below 30ft on O2 in the water.

I think a big disconnect we are going to end up having in these discussions is the severity of DCS that we're talking about, and the extend of IWR that we're going to do because of it.
Do I have some pain in my knee/shoulder etc which on my personally, if I get it before I get out, I'm not going to deem that worthy of going to a chamber and not just dropping back down for a bit. If I have any neuro symptoms, then yeah, get me to the chamber. If I'm already warm/dry and something comes on, then I'm going to call DAN and see how quick I can get to the chamber, and depending on how I'm feeling, sort it out from there.

me personally, cave centric, and not advocating obviously
If I can drop down to 20ft and my symptoms resolve *which they have twice before*, I'll hang out for 30mins, go up to 10ft, and hang out as long as I am warm/comfortable/have available O2. Get to the surface, do a surface deco for at least 10-15 mins while I shed all of my gear before I get out of the water, and then hop on O2 for at least a half hour. I have had to do that twice, once from an improper fitting harness in my right shoulder, the other in my knee from being dumb and slipping on a step and landing on it wrong *how I got a bubble in that same knee during the FAD study at Duke actually but several years after the fact*. Symptoms resolved in those instances immediately after I stabilized at depth, and I felt fine once I got out. That to me isn't worth the expense/hassle of going into the chamber for 6 hours. That would be a do as I say not as I do with any students obviously and they'd be booking it to the chamber, but not what I'd personally do.

Musculoskeletal or skin? If I'm in the water, I'm more than likely going back down. I have the O2 and I'm already in the water. No real risk in doing that. If I'm out and dry, it depends on how bad it is and I'll make that call myself
Any neuro or pulmonary symptoms? no way I'm getting back in the water. Surface O2 all the way to the chamber for that guy

My buddies or anyone around me gets to make their own decisions. I make sure that I have all the gear and gas to do Pyle's IWR table, and if they feel comfortable doing it, I'll support them in any and every way that I can.

tbone, thanks for clarifying. I don't think you'd derive any benefit from going deeper. The pressure effects on any bubbles present would be negligible, and adding inert gas could result in bubble growth.

For your two IWR episodes (shoulder and knee), how did you rule out musculoskeletal injury? It sounds like there were aggravating factors.

Re your decision process, for what it's worth, again, I'd advocate proceeding with caution. I may be interpreting your nonchalance incorrectly, but again, what you're advocating for yourself does involve medical diagnosis and treatment. It may seem benign, and having done it without incident twice can be a confidence booster, but it's not without risk.

Best regards
DDM

 

[tbone1004]

@Duke Dive Medicine I don't have any good way to rule out a musculoskeletal injury, however in both instances the symptoms went away once I arrived at depth. That said, even if it was an injury, I felt fine afterwards so who knows. I didn't have the FFM at that point, so wasn't going to 30ft, so what may be perceived as nonchalance is largely because it is essentially going back for more decompression that I just completed. Don't really see the added risk of going back in for another 30-60mins when I just got done with 60mins of deco.

 

[Duke Dive Medicine]

@Duke Dive Medicine I don't have any good way to rule out a musculoskeletal injury, however in both instances the symptoms went away once I arrived at depth. That said, even if it was an injury, I felt fine afterwards so who knows. I didn't have the FFM at that point, so wasn't going to 30ft, so what may be perceived as nonchalance is largely because it is essentially going back for more decompression that I just completed. Don't really see the added risk of going back in for another 30-60mins when I just got done with 60mins of deco.

Thanks tbone. That's where I would respectfully disagree - it's not essentially going back for more decompression, because you're getting in the water breathing O2 with the intention of treating a medical issue. While your symptoms were minor, seemed to resolve at depth on O2, and you suffered no ill effects, it's still a medical treatment.

Best regards,
DDM

 

[Johnoly]

..... I don't think you'd derive any benefit from going deeper. The pressure effects on any bubbles present would be negligible,....

If a bubble(s) was stuck on a spine hit (neuro), wouldn't going deeper on an acceptable nitrox mix help in moving/releasing the stuck bubble to stop further tissue damage?

Setting aside safety aspects, I think the 2 groups of pro/con IWR divers comes down to 'go deeper to move the bubble' versus ' give the bubble time to dissolve into solution'

 

[Duke Dive Medicine]

How much deeper, and what's an acceptable nitrox mix?

 

[Johnoly]

How much deeper, and what's an acceptable nitrox mix?

IWR will always have 2 camps. From the spearfishing community and talking to people at tournament weigh ins, no one formally reports doing IWR. But it's well talked about among spearos. I'd guess from those spearo's who took a hit, IWR was used 5 - 10 times more than going to a chamber, it's that wide spread.