Rebreather Went out of breath at the end of a dive with on a CCR

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Hi, not an asthmatic at all, passed all my lung exams with flying colours :cool: . It turned out that the medication I was taking for my psiorasis was the culprit. Stopped taking it and am back to normal since. For a while I was limiting my self to "rec" dives where I could live with 0.7 ppO2, which I easily tolerated.
Apologies I got you mixed up with the OP :D
 
I seriously doubt this long after the dive anyone will be able to figure out if the airways were constricting due to asthma, or they were filling with fluid due to IPE, or a little bit of both.

@Mod63 have you ever had exercise induced asthma before? Or had an asthma attack on a dive before? Is your asthma normally very well controlled?

(edited) Sorry @MiddlePilot these questions were for you. Hope you're feeling better and have some answers
I am feeling better but it looks like it everything is pointing to me having to stop CCR diving which is quite depressing tbh.

I am in my mid forties and didn’t have asthma exercise induced attacks since I was maybe 15? It all stopped when I started to do more exercise regularly. I never had asthma in diving and also I never had asthma developing so fast, usually it would be very gradual, unless I have a trigger like hay fever but I would have then warning signs before it gets really bad.

My asthma is normally well controlled, I was coming with a cold and that could be a trigger for having asthma but even then it would normally not develop so fast.

(I thought you may have completed to Mod69 instead of my nickname but wasn’t 100% sure :) )

I have about 70h on the unit without incidents.

The 3 days leading to the incident were:
  1. 3h40 at 12meters (I think we used 0.7 PPO2 that day)
  2. 2h05 with about 30mins at 40 meters and the rest were shallower drills
  3. 1h8 with about 20-25 mins bottom time at 55 meters
I don’t often do that long dives back to back but I have been doing a few times longer in 3 days but doing 2 dives of 2h to 1h30 in a quarry for example (multiples dives a day rather than a single long dive)
 
I have seen a diver with IPE twice in my life. In 1 case it was my own instructor we had to take out of a cave. Of course, under water we did not know what was wrong, only he shouted 'go out' in the loop and was not able to swim anymore. So we pulled him out. At surface he was wheezing like hell and we had to bring him out of the water. He was diving a non-CE ccr (I heard from others that the WOB of this quite popular machine would never pass the CE-tests, but don't know if this is true, I haven't dived it myself). The diver was quite old, but for his age fit (did other cardio-sports). After being on surface and 45minutes sitting, he was able to drive home himself again. So the coughing and wheezing cleared quite fast. He decided to quit diving after this happened.

The other was a younger diver, diving in very cold water, 3 degrees C. Also diving on a ccr, but this time a CE-unit, Inspiration like I dive. Diver was coughing and feeling could not get enough air, but was able to get out of the water herself. The couging and wheezing lasted a few hours, but was not that bad that a doctor was visited (and it was a long walk back to the car to get all the stuff in it). This diver continoued diving and although we lost each other a little bit out of sight (just sometimes contact over social media), 1-2 times a week diving is still done and also deep cold water technical diving on ccr.

In both cases, headache was not meant.

I have had my first real CO2 hit a few weeks ago, after diving ccr for over 10 years with all kind of extreme technical diving on ccr. I was diving my Inspiration ccr, the unit I own for over 10 years now, BMCL, moderate temperature water (8 degrees celcius whichs is for us in winter warm), but flooded my drysuit completely at 65m (probably a helmet was the cause, because it was required at surface here and I did not check due to this the neckseal). Because of this, my feet got too heavy for a normal horizontal swim, so it was very hard to swim the way back to the exit (was overhead), I did not want to stirr everything up. At 45m, a horizontal passage of about 125m, I was breathing very fast and got a headache, a horrible headache, and I did some coughs, but I felt I was out of breath. I decided to bailout as I knew what was wrong. Around 12m, the breathing seemed to be more or less normal again. At 6m I felt ok again, except still headache. After the dive I was able to get out of the water myself, was very heavy because my drysuit was full of water, walked the 250m to the car myself. Did some coughs because I was very cold. Changed my clothes, but did not have dry underwear, so was still not completely dry when I walked back for my bailoutcylinders. But did al myself. Never had a feeling of wheezing or such things. I was still partly wet and cold when we had after the dive a tour in the dry part of the mine, and even after a shower I still had a headache, the headache lasted hours.
The next day I did the same dive again on the same unit, but with new sorb of course, and did not flood my drysuit :wink: And happely, all went well. :D

So from what I can remember as main thing from the CO2 hit was the extreme headache under water (at surface it was already less, but not gone), and that it lasted for hours after surfacing. Under water, it felt like I breathing too fast like I was running fast, and this went quite fast ok again after bailout. There was no sign of wheezing. The rate of breathing was very high. The 2 cases of IPE I have seen did not have any headache, and the wheezing was there present, also a lot of coughing for 1-2 hours after surfacing. They decribed it as not getting enough air and water in the lungs. But there was no CO2 problem and bailing out in 1 case did not help. In 1 case, the diver was not able to help himself anymore, so needed help to swim to surface and get out of the water. When I surfaced after bailing out, I walked 3 times back to the water to get my own cylinders out of the water, I hold a camera from another diver and then I walked back to the car with my fins and camera in the hand. So was still able to do things, even if I was cold and heavy and had a headache.
 
To the OP out of interest what unit are using and in what lung configuration. I dive a KISS Classic and I have to be very focused on good breathing discipline due to the BM counter lungs, which inc hydrostatic lung load.

So long as I use my diaphragm to breathe in, it's all good, but I've had similar episodes to you when it felt like I was struggling to get enough oxygen in. Stress can increase this as can length of dive, fatigue etc and I also find that you can also end up with an odd nasal situation without good breathing technique, this results in negative pressure in the mask and a kind of snorting from the nose/throat as soft tissues get tired later in the dive.

I use a BOV and gag strap and these can also exacerbate it as the strap can you make you lazy, not grip the mouthpiece fully and allow soft tissue to relax in the throat area.

I appreciate these aren't exactly what you experienced, but early on in my CCR career I used to take time outs quite frequently on BO to calm my breathing down, but as I have got more disciplined it's much less of an issue even on loing swims in OHE.

Before the penny dropped I was considering modding the lungs to move them forward, using OTS, possibly even swapping to another unit, but happily as usual it was the pink squashy thing that was at fault.
 
To the OP out of interest what unit are using and in what lung configuration. I dive a KISS Classic and I have to be very focused on good breathing discipline due to the BM counter lungs, which inc hydrostatic lung load.

So long as I use my diaphragm to breathe in, it's all good, but I've had similar episodes to you when it felt like I was struggling to get enough oxygen in. Stress can increase this as can length of dive, fatigue etc and I also find that you can also end up with an odd nasal situation without good breathing technique, this results in negative pressure in the mask and a kind of snorting from the nose/throat as soft tissues get tired later in the dive.

I use a BOV and gag strap and these can also exacerbate it as the strap can you make you lazy, not grip the mouthpiece fully and allow soft tissue to relax in the throat area.

I appreciate these aren't exactly what you experienced, but early on in my CCR career I used to take time outs quite frequently on BO to calm my breathing down, but as I have got more disciplined it's much less of an issue even on loing swims in OHE.

Before the penny dropped I was considering modding the lungs to move them forward, using OTS, possibly even swapping to another unit, but happily as usual it was the pink squashy thing that was at fault.
I dive a JJ CCR standard config, back mounted over shoulder in high position.

I think I may have forgotten to diaphragm breathe on that dive. Felt a bit task loaded since we were running the unit in manual O2 add for a drill.

I remember that at the turn to get back to the shot I felt like my drysuit felt tight on the chest area and I pulled a bit on the fabric but that didn’t feel particularly alarming at the time.
 
I dive a JJ CCR standard config, back mounted over shoulder in high position.

I think I may have forgotten to diaphragm breathe on that dive. Felt a bit task loaded since we were running the unit in manual O2 add for a drill.

I remember that at the turn to get back to the shot I felt like my drysuit felt tight on the chest area and I pulled a bit on the fabric but that didn’t feel particularly alarming at the time.
Task loading could easily be a part of this leading to chest breathing, less than full ventilation etc., ascents are busy enough without the added issue of running manual on an ECCR, throw in a bit of sub optimal loop volume and I think you will find on another day with less stress and more discipline you will be fine.
 
Outside of IPO/IPE, any other likely causes? Has anyone had a similar accident and went back to diving - perhaps just OC scubydoo?

#AskingForAFriend
 
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