Emergency pressure treatment when bent?

[Rhone Man]

A question I have always wondered about is if you are doing your deco, and you start to feel a twinge, do you blow off the rest of your deco and surface, follow your planned schedule, or go back down a stop and bulk up your stop times.

Never found anything in the manuals which suggests best course of action in this situation. Suspect it really is a choice of evils at that stage.

 

[DCBC]

Let's face it . . . if you develop major DCS symptoms in an area where transport to a chamber can't be done in a timely fashion, you are in serious trouble. But taking someone with serious symptoms back into the water requires major preparation -- you may survive a spinal cord embolism as a paraplegic, but you're extremely unlikely to survive an oxygen toxicity event unless you're in a FFM and have experienced tenders.

For mild (Type I) symptoms, I don't think there is ANY question that you are better off on the surface, breathing oxygen, than you are back in the water.

The real answer is, if you are doing aggressive dives in a remote location, have an on-site chamber

As discussed on the other thread, my point exactly! There's many things that complicate in-water treatment of DCS (vomiting and hypothermia are but two). Diagnosis of DCS can be difficult (other things can provide similar symptoms). Even if DCS is established, is it Type I, II, or III? How many of us plan to bet the life of the victim on our expert diagnosis? Liability is also another real concern!

Divers have to be realistic when assessing risk. Commercially, you don't go into a decompression situation without the correct equipment and team. Some sport divers tend to push the limits of gas absorption without proper preparation.

 

[DevonDiver]

I posted this account recently on a different thread, but I thought it might add some balance to this discussion....

The only experience I have with a serious DCI hit is this... as my buddy (tech dive) had a particularly nasty hit with these symptoms (plus severe weakness and bilateral leg immobility).

We were on a technical liveaboard trip, 2 days from land. The condition resolved after prolonged (3 hours) dry FO2 and hydration treatment. Victim made a complete recovery. (phew!).

The (deep air) dive went perfectly, including decompression, but symptoms presented immediately and severely on exiting the water.

The victim was using an adjustable 'comfort' harness and, subsequently, a dive doctor informed him that the most likely cause of the hit was due to having an over-tightened harness, coupled with arm immobility during prolonged decompression, that prevented effective off-gassing from his upper-limbs. This was based on the way that symptoms presented (chokes) immediately on releasing his shoulder straps after exit from the water. This was followed by extensive cutis marmorata (marbleized skin) around his torso that was noticed when he removed his wetsuit (very obvious and could not be confused with a common 'skin rash'). He then lost mobility in one leg and suffered fatige to the point of semi-consiousness.

Points to note;
1. Chamber evacuation was not an option (within 24 hours).
2. Casualty was effectively immbolized, with reduced consiousness.
3. Re-entering the casualty to the water would have been very risky.
4. Casualty was administered 100% O2, hydrated and laid supine.
5. Major DCI symptoms resolved within 3 hours.
6. Minor fatigue and ache remained for 12 hours.
7. Casualty was assessed by a dive doctor at a recompression chamber 18 hours after exiting the water.
8. Casualty did not require recompression treatment and recovered full health within 48 hours.

So, from my experience, in the event of a DCI hit (type I or II), the approved method of treatment using 100% O2 and hydration proven it's effectiveness.

Either method (surface O2 or IWR) could work and either may fail. The difference is that one method places the casualty in no further danger, wheras the other places them back into a situation where any number of complications could easily kill them.

 

[DCBC]

I posted this account recently on a different thread, but I thought it might add some balance to this discussion....

The only experience I have with a serious DCI hit is this... as my buddy (tech dive) had a particularly nasty hit with these symptoms (plus severe weakness and bilateral leg immobility).

We were on a technical liveaboard trip, 2 days from land. The condition resolved after prolonged (3 hours) dry FO2 and hydration treatment. Victim made a complete recovery. (phew!).

The (deep air) dive went perfectly, including decompression, but symptoms presented immediately and severely on exiting the water.

The victim was using an adjustable 'comfort' harness and, subsequently, a dive doctor informed him that the most likely cause of the hit was due to having an over-tightened harness, coupled with arm immobility during prolonged decompression, that prevented effective off-gassing from his upper-limbs. This was based on the way that symptoms presented (chokes) immediately on releasing his shoulder straps after exit from the water. This was followed by extensive cutis marmorata (marbleized skin) around his torso that was noticed when he removed his wetsuit (very obvious and could not be confused with a common 'skin rash'). He then lost mobility in one leg and suffered fatige to the point of semi-consiousness.

Points to note;
1. Chamber evacuation was not an option (within 24 hours).
2. Casualty was effectively immbolized, with reduced consiousness.
3. Re-entering the casualty to the water would have been very risky.
4. Casualty was administered 100% O2, hydrated and laid supine.
5. Major DCI symptoms resolved within 3 hours.
6. Minor fatigue and ache remained for 12 hours.
7. Casualty was assessed by a dive doctor at a recompression chamber 18 hours after exiting the water.
8. Casualty did not require recompression treatment and recovered full health within 48 hours.

So, from my experience, in the event of a DCI hit (type I or II), the approved method of treatment using 100% O2 and hydration proven it's effectiveness.

Either method (surface O2 or IWR) could work and either may fail. The difference is that one method places the casualty in no further danger, wheras the other places them back into a situation where any number of complications could easily kill them.

Agreed, but regarding point one, 24 hours should not be considered a ceiling limit for a chamber. Divers have been treated successfully after 3 days. The point you make about hydration is one that's too often overlooked by many recreational DMs and Instructors. It's a key element in any successful treatment. Excellent answer!

 

[DandyDon]

Very good point...

Either method (surface O2 or IWR) could work and either may fail. The difference is that one method places the casualty in no further danger, wheras the other places them back into a situation where any number of complications could easily kill them.

Maybe those who want to experiment would be safer making homemade chambers from 3 ft PVC, Plexiglass, large hose bands for reinforcements, spg and O2 pump. Just let me get off the boat before you fire it up.

 

[DevonDiver]

A question I have always wondered about is if you are doing your deco, and you start to feel a twinge, do you blow off the rest of your deco and surface, follow your planned schedule, or go back down a stop and bulk up your stop times.

Never found anything in the manuals which suggests best course of action in this situation. Suspect it really is a choice of evils at that stage.

Decompression is the process of OFF-GASSING.

If you felt a twinge (that may-or-may-not be DCI), then aborting your deco would only mean that you arrived at the surface with more nitrogen in your system.

If the twinge was indeed symptomatic of DCI, then it would mean that bubbles had begun to form in your body. The potential development of those bubbles (in size and severity) would be, in part, dictated by the amount of nitrogen in your body to feed their growth.

Thus, completing your deco would reduce the growth potential of the bubbles, even if they had begun to present before reaching the surface.

Obviously, common sense dictates that if the DCI symptoms became so severe as to pose a risk to life by remaining in the water, you should exit and seek immediate medical care/evacuation. Also, if recompression treatment was extremely close at hand, then it may be prudent to abandon the decompression and rush to the chamber.

There are recorded cases of DCI presenting prior to surfacing; especially DCI caused by Isobaric Counter-Diffiusion (ICD).

ICD occurs every time you switch from a light to heavy gas, but when specific conditions arise (gas switch at a decompression ceiling incurring a substantial jump in END) then severe and immediate DCI can present. Deep gas switches generally impact fast tissues, particularly the vestibular organs. Inner Ear Decompression Sickness has been recorded numerous times immediately upon deep stop gas switches. DCS symptoms can arise anywhere, but are most commonly experienced as debilitating extreme vertigo and vomiting.

From what I have read/heard, in these instances the victims had completed (or attempted to complete) their decompression before exiting the water and seeking medical care. The story/video of Don Shirley's support dive during Dave Shaw's infamous body recovery operation in Boesmansgat, South Africa illustrates this.

An article HERE describes Shirley's experiences with DCI on the (long) ascent from his dive....

With hours of slow ascent and decompression ahead of him, he clung to a faint hope that his friend might make it. But then, Shirley plunged into a nightmare of his own. At about 50m, feeling faint, a gas surge in his left inner ear created a helium bubble that destroyed his balance. Spinning around, moving up and down and from side to side, utterly disoriented, he reached out for the line and somehow managed to seize it before he span away into the void. For hours, he continued decompression in a fog of nausea and exhaustion.

'Everything I did made me vomit,' he recalls. 'I got to the stage where I didn't have the energy to pull the gas from my regulator into my lungs.'

In the end, Shirley's ascent lasted more than 12 hours - and he then spent over seven hours in the decompression chamber, followed by six more treatments during the following week. Physically he was fine, but it took months to relearn how to balance and, he says, 'to get my head straight'.

 

[graywhale]

Thanks for posting cases of IWR gone wrong. Case # 10 is the worst. In case #4 the divers died, but we really do not know why and we do not know what the divers did. Also they went down without a safety diver. There is a lack of details. The worst one to scare people is case number 10 and is as follows:

A young diver experienced pain-only symptoms of DCS after an unknown dive profile. He made three successive attempts at IWR (presumably breathing air), each time worsening his condition. After the third attempt, his condition had degenerated into quadriplegia. Because of transport delays, he did not arrive at a recompression chamber until about three days after the incident. Saturation treatment yielded no improvement in his condition, and he remained permanently paralyzed.

So he screwed himself via IWR. But unfortunately we do not know what he did and I think it is the fear that if not done properly something like this can happen. You can definately make it worse if done wrong. That's why it is not recommended. You really have to do it right.

That calls for simplicity. and here the safest procedure is the Australian method where by the victim is taken back down to 30 feet on 100% oxygen with a safety diver and slowly brought back up. With this, the IWR can be broken off at any time and the victim brought back to the surface without further compounding the issue. No oxygen toxicity, not additional Nitrogen load, etc...

So if I were a DR. and were asked if IWR should be done when a chamber is not available, I too would only give the go ahead if I am convinced the divers around the victim know how to do it and the victim is in a condition to go back in.

And please don't forget this is for a situation where a chamber is not available. Regardless of the reason.

 

[graywhale]

Rhone Man. Here is case #4 that goes to your question:

EDIT: It was case #3 where the two IWR divers died, not #4. Case #4 is as follows:

Case #4. Hawaii.

" After ascending from his second 10-minute dive to 190 feet, a diver followed the decompression `ceilings' suggested by his dive computer. As he was nearing the end of his computer's suggested decompression schedule, he suddenly noticed weakness and incoordination in both arms, and numbness in his right leg. He immediately descended to a depth of 80 feet where, after 3 min, the symptoms disappeared. After a total of 8 min at 80 feet, he slowly ascended over a period of 50 min to 15 feet (his companion supplied him with fresh air tanks). He remained at this depth until his decompression computer had "cleared". He felt tired after surfacing, but was otherwise asymptomatic."

 

[graywhale]

Here's another interesting case:

Case #5. Hawaii.

While conducting a solo dive at a depth of 195 feet, a diver became entangled in lines and mesh bags. In his struggles to free himself, he extended his time at depth well beyond the intended 10 minutes, and squandered much of the air he had expected to use for decompression. Upon freeing himself, he immediately began his ascent, but was mortified to discover that the boat anchor had broken loose and was gone. Swimming down-current, he fortuitously saw the anchor dragging across the bottom, and quickly caught up with the anchor line at a depth of 60 feet. At this time, his decompression computer indicated a `ceiling' of 70 feet, and his pressure gauge showed that his scuba tank was nearly empty. He slowly ascended to the surface and quickly explained his predicament to his companion in the boat. While waiting for his companion to rig a regulator to a fresh tank of air, he began feeling symptoms of severe dizziness and had problems with his vision. Grasping the second tank under his arm, he allowed himself to sink back down, nearly losing consciousness. Upon reaching a depth of 80 feet, his clouded consciousness fully resolved, and he remained 10-15 ft below his computer's recommended `ceiling' during subsequent decompression. Although he eventually exited the water before his computer had "cleared", he did not experience any additional symptoms.

 

[DevonDiver]

So if I were a DR. and were asked if IWR should be done when a chamber is not available, I too would only give the go ahead if I am convinced the divers around the victim know how to do it and the victim is in a condition to go back in.

If a consensus was every achieved on an 'approved' method, then it would be great if a training course was available.