Got bent, preferred IWR to my local chamber

[AbyssDiver1983]

Don’t really see the harm in it. Used to dive that way cause I didn’t have a multi-gas computer anyway. In fact I remember 10 years ago very few divers had the multi-gas and also used to dive that way. I’ve been diving for a long time, first time I have any symptoms is when I used my new multi gas computer this season. I’m not saying it’s technically the best option, some might prefer just adding some deco time or a small 100% pony and do some flushing at 5-6m. But for me this method was fool-proof for a long time.

Bearing in mind most of my dives are technical in the sense that they are a bit long, 40-50m deep and I use a deco mix. This does not apply to cave or trimix diving.

True that technical divers prefer to know their exact CNS O2%s and tweak the algorithms instead of adding unknown variables, but for just increasing the safety margin on an open water deco dive, and adding the fact that the whole thing isn’t really an exact science, I don’t think it’s a wrong move.

 

[OTF]

Just run a more conservative gradient factor, GFs exist for that purpose and achieve the same thing.

 

[Peter69_56]

Seems your wife got bent more than once. Sorry to hear that, but it shows true passion for the sport that she’s still diving technical. Respect. Did she do HBOT every time or did she opt for other types of treatment?

Unfortunately the first time we couldn't get anyone interested in helping. We were told we had to go to a doctor to go to the local chamber at the navy depot at Bruni. Saw the doctor and he said just a rash, said she has pain, rash and itchiness, he prescribed antihistamines, and panadol. I asked for at least oxygen. Nope not needed. She had to just suffer it all night and we were not happy given we were sold the trip on the basis that Bruni had an active chamber.

Next time was Vanuatu and we went across to the dive shop and picked up one of my deco mixes and used that. By morning all symptoms gone. Third time it was in Philippines and she was on oxygen from the dive shop all night. After that time we went home and attempted to get a doctor referral to a heart surgeon as I suspected PFO. Local Australian doctor was useless and got angry when I refused to accept her diagnosis of needing an EKG. She needed an Ultrasound stress test which will show a PFO. I had to see 2 GP's before I got the referral, but sadly the hole is small and also not straight through the heart wall, it enters the skin, travels along the skin wall and pops out somewhere else. SO there is no fix for it. Another heart surgeon had a look and whilst he said the PFO is near non existent, clearly its there enough to cause a problem unless we follow a special dive procedure. On any dive, recreational or tech, after the dive time is finished, she must do 3-5 min on pure O2 at 6m. Only then will she not get bent. She also dives a very non aggressive algorithm. After she has finished all the deco and additional O2 time, we then take another 3-5 min to go from 6m to surface, one deep dive a day and after 3 days take a break. It works for her, but it must be followed in detail. We did a dive one day to about 15m through a sea tunnel to an open sea cave, came up, down to 10m up again to another open cave, then back out all on air only as they didn't have the O2 ready, and she showed signs of a skin bend. So unless they can provide the gases required each day and allow her only one dive a day etc we do not use a dive shop which cant provide our needs.

I on the other hand have had no issues diving as deep as 105m and multiple dives a day for a number of days.

Another friend of ours was listening to us talk about the issues and stated that sometimes after a dive his vision seemed affected. I advised him to go get checked, and he found he had 3 PFO which subsequently have been fixed. His mate who is overweight showed me a rash he got after a few days diving deep on aggressive algorithms and this was found to be a bend as well, but in his case more weight issues and aggressive diving.

So one thing we learned is that many GP doctors have no idea about dive medicine, the good ones listen and help, the bad ones force their ideas onto you so as not to lose face.

 

[boulderjohn]

When I had DCS, I made the same mistake you did. There was absolutely nothing in my dive profile that should have put me at risk. It should have been perfectly safe. I therefore went into denial and delayed treatment for what should have been obvious DCS. I read a study from a year or two ago that indicated that the overwhelming majority of DCS cases happen to people who dived well within limits. That should not be a surprise, since almost everybody dives within limits these days. It happens.

As for CNS limits, I have made modest efforts to find details the source for the established CNS limits without success. I suspect that when they were established, they were not much more than a wild guess.

 

[Peter69_56]

One issue that will arise is that if you say just leave your computer on air, and disregard that you have actually switched, whilst for deco purposes, it helps you have to be careful not to get an oxygen hit, in particular if the dives are very long. This is more so when running high levels of oxygen at depth at say 55m and a long dive, and then switching to mixed gases and long decos on the way back you can quickly reach your O2 limit (more so on a breather running high levels of O2 to clear deco quickly).

 

[AbyssDiver1983]

Just run a more conservative gradient factor, GFs exist for that purpose and achieve the same thing.

I already run a conservative 30/70, most of the divers I know run GFhis at 80+. I already add deco time as you can see from my profile. Just going to do what used to work fine for me for years when I didn’t have the option to switch.

 

[AbyssDiver1983]

One issue that will arise is that if you say just leave your computer on air, and disregard that you have actually switched, whilst for deco purposes, it helps you have to be careful not to get an oxygen hit, in particular if the dives are very long. This is more so when running high levels of oxygen at depth at say 55m and a long dive, and then switching to mixed gases and long decos on the way back you can quickly reach your O2 limit (more so on a breather running high levels of O2 to clear deco quickly).

Very true. But from what I know from monitoring my CNS tolerance on O2 (320% when doing the IWR) and the fact that I’m going to cut down my dive times, I’m not really concerned about O2 exposure. I may be wrong, but the CNS O2 value has never been a reason for me to hurry out of the water or switch back to my bottom mix. Ever.

 

[AbyssDiver1983]

Unfortunately the first time we couldn't get anyone interested in helping. We were told we had to go to a doctor to go to the local chamber at the navy depot at Bruni. Saw the doctor and he said just a rash, said she has pain, rash and itchiness, he prescribed antihistamines, and panadol. I asked for at least oxygen. Nope not needed. She had to just suffer it all night and we were not happy given we were sold the trip on the basis that Bruni had an active chamber.

Next time was Vanuatu and we went across to the dive shop and picked up one of my deco mixes and used that. By morning all symptoms gone. Third time it was in Philippines and she was on oxygen from the dive shop all night. After that time we went home and attempted to get a doctor referral to a heart surgeon as I suspected PFO. Local Australian doctor was useless and got angry when I refused to accept her diagnosis of needing an EKG. She needed an Ultrasound stress test which will show a PFO. I had to see 2 GP's before I got the referral, but sadly the hole is small and also not straight through the heart wall, it enters the skin, travels along the skin wall and pops out somewhere else. SO there is no fix for it. Another heart surgeon had a look and whilst he said the PFO is near non existent, clearly its there enough to cause a problem unless we follow a special dive procedure. On any dive, recreational or tech, after the dive time is finished, she must do 3-5 min on pure O2 at 6m. Only then will she not get bent. She also dives a very non aggressive algorithm. After she has finished all the deco and additional O2 time, we then take another 3-5 min to go from 6m to surface, one deep dive a day and after 3 days take a break. It works for her, but it must be followed in detail. We did a dive one day to about 15m through a sea tunnel to an open sea cave, came up, down to 10m up again to another open cave, then back out all on air only as they didn't have the O2 ready, and she showed signs of a skin bend. So unless they can provide the gases required each day and allow her only one dive a day etc we do not use a dive shop which cant provide our needs.

I on the other hand have had no issues diving as deep as 105m and multiple dives a day for a number of days.

Another friend of ours was listening to us talk about the issues and stated that sometimes after a dive his vision seemed affected. I advised him to go get checked, and he found he had 3 PFO which subsequently have been fixed. His mate who is overweight showed me a rash he got after a few days diving deep on aggressive algorithms and this was found to be a bend as well, but in his case more weight issues and aggressive diving.

So one thing we learned is that many GP doctors have no idea about dive medicine, the good ones listen and help, the bad ones force their ideas onto you so as not to lose face.

Wow that really puts things in perspective.. Your wife is a champion. Around here the most patients any Dr has treated with DCS in their lifetime is 1. We’re on our own.

 

[AbyssDiver1983]

Wow that really puts things in perspective.. Your wife is a champion. Around here the most patients any Dr has treated with DCS in their lifetime is 1. We’re on our own.

The hyperbaric chamber Dr/technician has seen the most cases and he won’t do treatment if you don’t have muscle weakness. Genius

 

[boulderjohn]

I already run a conservative 30/70, most of the divers I know run GFhis at 80+. I already add deco time as you can see from my profile. Just going to do what used to work fine for me for years when I didn’t have the option to switch.

Is 30/70 "conservative"?

What does "conservative" actually mean? What you describe is how the word is usually used in diving, but if by "conservative" you actually mean "safer," you may be wrong in that belief. There is no doubt that a GF high of 70 is safer than 80+. It is the GF lo of 30 that is of concern. In most modern diving thought, a GF that low is riskier than a higher one.

Evolving Thought on Deep Decompression Stops
Gradient Factors in a Post-Deep Stops World