Why the reluctance to call for help?

[sas steve]

Sorry Missed a lot of the latest stuff here just caught up with a few bits though.

(Quote) Ask the hyperbaric tec on here if he's a qualified doctor(Quote)

No!!!

I'm far more experienced than that in hyperbaric medicine.
Also:EMT/ DMT.
NAEMT member (National Association of Emergency Medical Technicians.)
Hostile environment First Aid Instructor /assessor.(Private Security)

I've seen just about every type of bend you can imagine and a few I thought couldn't be real.
Female Lymphatic bends are quite interesting to see.(Imagine Jordan )

Anyway i'll continue to sit back and read the rest of the stuff later after I'm out of the pot.

[Mark Chase]

Originally Posted by sas steve

Sorry Missed a lot of the latest stuff here just caught up with a few bits though.

(Quote) Ask the hyperbaric tec on here if he's a qualified doctor(Quote)

No!!!

I'm far more experienced than that in hyperbaric medicine.
Also:EMT/ DMT.
NAEMT member (National Association of Emergency Medical Technicians.)
Hostile environment First Aid Instructor /assessor.(Private Security)

I've seen just about every type of bend you can imagine and a few I thought couldn't be real.
Female Lymphatic bends are quite interesting to see.(Imagine Jordan )

Anyway i'll continue to sit back and read the rest of the stuff later after I'm out of the pot.

I obviously knew this already.

Perhaps you'd like to coment on the level of awarenes common in medical doctors concerning diving related DCI?

In my experiance its pretty bad.

ATB

Mark

[sas steve]

I agree Mark that the average GP knows nothing about DCI or at the very least only enough to be of little use.

When my GP asked what i did for a job and I said Hyperbaric technician He said Oh!! What's that then?

Our Doctors here are GP's that have had specialist training in Hyperbaric medicine and most if not all are divers as well, they still regularly ask our advice when diagnosing patients which is nice as they recognise our experience with the real thing.

Steve

[Mark Chase]

Originally Posted by Scubee

Now here's a question...

i have been running up a few profiles, using a specific gas, and variables in the programme based, not on my experience (because I have done precisely 2 trimix dives, both in training), but based in anectdotal and empirical evidence of those who have far more experience than me.

Using the setting on my software i was using last year (on air/nitrox), I get a run time of 102 minutes (based on a bottom time of 25mins and loss of deco gas). Using the safety factors suggested to me, the same dive would require a run time of 169 minutes.

If I choose to use last years settings (I did a fair few dives and didn't get bent), and get out the water after 102 minutes, I could have missed, theoretically, 60 minutes of stops, and should be on a chopper.

So.... if you miss stops the profile could still be perfectly acceptable, depending on the variables used in the planning.


(edit: obviously I was working this lot out while the others were posting )

Yep, you now understand the whole point.


I dont get excited missing 20mins of stops folowing 45mins at 60m on 18/45 32 and 80. All i did was jump from 20/80 to 20/100GF


On the Curvia dive last Monday which was only 37m the diver with an issue had a 40min deco plan on VPMB 5. I was running 10/90GF and had 22mins. He told me hed missed three deep stops but I didnt get very excited about it.

A: he was on nitrox not trimix and

B: his plan was already nearly double my own and trebble my rock bottom for this dive.

He decided to stay on 80% on the boat which was cool. We didnt call it in and SJ did do checks on the diver just in case.

An intelegent assesment decided a chopper realy wasent necessary.


ATB

Mark

[chrisch]

Originally Posted by Janos

...
PS - As an aside, I don't have a VPM model with me, but I think you're talking cobblers when it comes to missing ten minutes of stops. What settings are you using? Using Bulhman 30/85 gives me 3 minutes of stops. But let's not let the facts get in the way of a story.

HLPlanner (freeware) 10% conservatism. 14min stops at 4.5m air deco.

I use this software for bailouts as it generates a table. TBH I would make a 30m/20min air dive on the computer (which is Buhlmann ZHL8) I was just looking for a good example of the different approach in deco models

Chris

[cazyoung]

Having read this thread from start to finish the impression it gives to an outsider who does not dive in UK is that there is a rather large amount of macho attitude and point scoring going on!!

Helens tongue in cheek comment was spot on.....

There have been some very valid comments from the pot tech and having worked in neurology and neurosurgery for some years I agree with him. No I am not a doc....

Just my twohappence worth from someone looking in from the outside.

[chrisch]

Originally Posted by cazyoung

Having read this thread from start to finish the impression it gives to an outsider who does not dive in UK is that there is a rather large amount of macho attitude and point scoring going on!!
....

I think, in all honesty, there is a clash over attitudes amongst different groups of divers. You are right in that the macho "I don't get bent" group are problematical and this group of people's repeated denials of any issues have generated an equally irrational (and "macho") "you're in denial - I know better" group.

Anyone that has undergone any level of technical training will have been educated that DCI denial is an issue and that we, as a community, should work to combat it. People like Mark who undertake what are in reality nearly experimental dive profiles are taught to self diagnose and to check up on the other team members. Its rather patronising to then be told missing a minute or two's stops is a major issue. You're now arguing about decompression theory not about decompression illness. Such I guess, is the nature of Internet debate and its propensity to wander off topic and to draw in other issues.

Chris

[AM1]

Originally Posted by Mark Chase

So if i am running a 20/80 GF and my buddy runs a VPMBlevel 2 and get's out of the water 20mins before me should i call a chopper? I mean hes obviously missed 20mins of stops by my calculations.

Again you are missing the point - every call is not to call for a chopper. It's lining up the ducks. Missed deco is missed deco from your own individual deco plan, not a comparison between models which output different deco times. Whether or not your mate can exit the water quicker because he has less conservatism or a different plan is not the point. The point is if that plan has been cut short or missed deco has occurred which was not expected. Yes silent bubbling occurs on every dive but when decompression is missed silent bubbling can be causing damage that may not be immediately apparent.

Originally Posted by Mark Chase

Sorry but i don't agree. If the diver tells me before the dive if he misses stops he wants the chopper fine but aside from that we will logically asses the situation. I have blown of 15mins of stops just because I needed a piss and No I didnt call out the CG to let them know. I know what i am running and i know that on occasion i can push it.

You don't know that, you took a gamble and were lucky. Or you were running major conservatism, still no guarantee. Whether the diver tells you or not before the dive is irrelevant as denial is a powerful phenomenon and you should give them the best fighting chance by at least making a phone call for advice. If one of your mates misses stops then you're doing them a disservice by not at least warming up the CG to the fact so that if anything does develop, a faster response is possible. What's the worst that is going to happen, they get a bit pissed off with you? They'll be a whole lot more pissed off if they develop symptoms later and you ruled out a phone call on the basis of a few poxy strength tests. You should insist on getting advice in the event of missed decompression, especially on dives involving helium, regardless of how many people suggest that it will be ok.

Originally Posted by Mark Chase

Thats not been my experience. They want details of the dive depth deco deco missed what the computer reads etc etc. Then they ask about the diver can he stand, is he stable, where does it hurt.

Yes that's triage. If they have 5 potentially bent divers they have to make a difficult decision with relatively little information. Which is why they want to be warmed up as soon as possible, not called out at the last minute, possibly depriving someone in greater need of assistance.

Originally Posted by Mark Chase

hyper or hypo-reflexia, clonus, babinski, hoffman's test etc very funny
Its a subtle neuro exam I could teach you to do in a morning tops.
(Not that you don't already know it i am sure).
As an example the highly complex and technical "Babinski test" is the one where they run a pencil from the heal of your foot to the toe. They are looking for movement away by the foot and the toes to turn down. If it dosent do this its a sign of spinal dammage.
Now have we all got that or would you like it explained again.
Deep tendon reflex love the technical name for push pull strength tests. Whats the tec name for the gripping of the two fingers "digitalis compresus maximus." Say it all in lattin it makes people sound reeely clever. I always refer to Anobis punctatum SPP in my reports as it sounds so much more intelegent than wood worm.
Actualy the squeezing of the fingers and thumb reflex test is called the Hofmans test Look for weeknes in the hands and tap the fingernails of the third and forth finger. If the thumb twitches, thats bad. This is another test for leasions in the spinal chord.

That's all wrong. Babinski is looking for the toes to fan out to indicate damage. A non-positive Babinski doesn't rule out spinal damage. Deep tendon reflex tests are nothing whatsoever to do with push/pull tests. Push/pull are motor strength tests. Deep tendon reflexes are tapping the reflexes to check whether they are brisk, low or absent. Tendons when tapped trigger the stretch reflex in the muscle, absolutely bugger all to do with strength testing. Reflexes are actions performed involuntarily in response to impulses sent to the central nervous system. Alterations in reflexes are often the first sign of neurological dysfunction, i.e. damage to the nervous system pathways. Observing reflexes is the most objective part of the neurological exam, since the reflexes are not under voluntary control and testing does not depend on the patient's cooperation, attitude, or awareness. You got a rubber mallet in your dive box? For the record, I don't believe for a second that a layperson could necessarily elicit clonus either. Even a few beats of clonus at the ankle may indicate damage taking place, yet you're saying on the basis of a few poxy tests that can give a false negative, that you'll rule out making a call to a doctor.

Originally Posted by Mark Chase

CNS and PNS dont come into my discussion.

Oh right, CNS isn't relevant? I rather like my cerebrum. So are you going to assess a potentially bent diver by a few push and pull tests?! Did you forget about cranial nerve tests, full motor system, sensory, co-ordination, cerebellum, gait, mental status etc? All well and good doing a few little tests to look for damage in ONE area...but a doctor will evaluate a potentially bent diver properly, looking and assessing for damage in a multitude of areas. That's their job. If you are not medically qualified, I do not believe you are in a position to perform the full battery of neurological tests, nor to make a judgment call about your mates missing deco.

Originally Posted by Mark Chase

Some people decide to get back to shore get in the car and drive to the pot for a niggle in the elbow. Thats not the same as ignoring it all to together and I am reasonably confident that avascular joint necrosis doesn't happen in a few hours.

Yes and if you phone them first and line them up at least they know what to expect. If every possibly bent diver just turns up the chamber it doesn't help the relevant authorities to co-ordinate treatments or prioritise in advance.

If one of your mates missed decompression (for whatever reason) and got out of the water in some sort of denial or crossing their fingers that it wouldn't develop and you just took their word for it that it would all be fine and you shouldn't phone a doctor even for advice, you would be remiss and not a proper mate. Especially on deeper dives using Helium, missing a short amount of deco could do some damage which might not be evident at first. I have seen this first hand. You have no right whatsoever to play God and making a decision that automatically cuts off help and advice for your mates is patently wrong. A bit of common sense would mean you err on the side of caution. Performing some scooby 5 minute check on the boat and deciding yourself that the lack of positive signs means your mate is fine is just downright irresponsible and selfish. You don't have the medical experience to decide what constitutes an obviously abnormal sign or a false negative with some of the neurological testing.

Let's get real - it's a phone call we're talking about here to line up the ducks, not a full blown chopper call every time. It's basic common sense. On a deeper trip I would ring up the CG/local pot anyway beforehand and let them know what's planned and that we'll confirm the all ok at X time OR seek advice/assistance. So far they've never told me to stop wasting their time.

Regards
AnneMarie

[chrisch]

Originally Posted by AM1

Again you are missing the point - every call is not to call for a chopper. It's lining up the ducks. Missed deco is missed deco from your own individual deco plan, not a comparison between models which output different deco times. Whether or not your mate can exit the water quicker because he has less conservatism or a different plan is not the point. The point is if that plan has been cut short or missed deco has occurred which was not expected. .....

With respect you are missing the point. You are still arguing about decompression models. If you have built (for example) 20% conservatism into your plan and are forced to cut short the obligation that requires all that has happened is you have changed plan.

In fact, I think this is the nub of it. We are arguing about missed decompression stops and some read that as below the minimum acceptable decompression and others see it as having a plan change.

Chris

[AM1]

Originally Posted by chrisch

With respect you are missing the point. You are still arguing about decompression models. If you have built (for example) 20% conservatism into your plan and are forced to cut short the obligation that requires all that has happened is you have changed plan.

In fact, I think this is the nub of it. We are arguing about missed decompression stops and some read that as below the minimum acceptable decompression and others see it as having a plan change.

Chris

With respect, it is you whom is missing the point.

Conservatism on some of these models is a joke and should be doubled, if not tripled for sub 100m dives. VPM conservatism is humerous at best. This is exponential the deeper you go and longer you stay. Particularly with He use.

If you are forced to cut short the plan and then have done the dive with no conservatism whereas you are used to adding 20% then again, where's the issue with making a call just to have a chat. That might be the day you are dehydrated or just plain fucking unlucky and get bent purely for diving right on the limit.

There are no known quantities with sub 100m diving, your day is going to come some day, it's just a matter of time. All the models and conservatism in the world don't change that and shaving down the conservatism is only increasing the risk. If I had done a sub100m and missed my conservatism and had to dive right at the limit, I would make a phone call anyway because I know I need that conservatism and that I may be on the edge of a bend without it. Same as most other people in this range of diving.

Pretty much every single person that I know who used VPM with no conservatism on sub 100m dives with any decent bottom time has commented that it's too aggressive. So if any of them missed time from the schedule but said oh it's still within the table cut for the dive, bollocks, it has a known propensity for being too short, in some instances, too short EVEN with conservatism.

I don't think the CG is going to tell anyone to bugger off and stop wasting time just for letting them know your plan didn't go to plan and you're keeping an eye on it.