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mempilot · 1st May 2008, 14:36

Lance,

You are spot on.

IMHO, hypoxia is the more dangerous situation. I've experienced it in the altitude chambers, and it wasn't until watching the video of the event afterwards that I realized how f'd up I was and unable to do the simplest tasks.

This is why I use the ADV for a @1.0 PO2 DIL flush at max depth. Breathing out while hammering the ADV and crossing the left arm over the CL's will push a lot of gas through the loop in an instant. Hammering DIL, even if not needed, will not kill you.

The only time I use O2 manual injection is for flying manually for practice, finite bouyancy control in shallow water, 6m O2 flush, or after a solenoid failure. Like Lance, I believe there is plenty of time to deal with high PO2, such as the possible solenoid stuck on or manual gas bypass stuck on. These two problems are real obvious and very easy to deal with in a calm manner. Remember OC days? Roll the offending post off, right? Or, even easier if it's the MGBP valve: Remember the stuck drysuit inflation valve drill? Pop the hose off the valve for an immediate bandaid.

Hyperoxic is a matter of dose and time. Hypoxia is a matter of just a few breaths. So unless one is conducting dives at up around 1.6 PO2 for very long periods of time, a spike above that can be tolerable while one deals with the situation prior to experiencing hyperoxic tox symptoms.

As for handset and HUD monitoring: Absolutely important for all of this. "Know your PO2". And if we do all this right, hypoxia would be a huge mistake and so hyperoxia would be as well. So one has to look at the possible failures that could cause these problems and the solutions to them.

Rebreather failures that impact PO2 are fairly easy to deal with if practiced and understood. Diver failures are usually the cause of hypoxia, and can be very difficult to deal with in the mental state the condition leaves you in. It can also be like walking off a cliff. One breath you are fine. The next breath you are incapicitated. I like having the ADV and known end result PO2 of using it to immediately put breathable gas into the loop. I also put a DIL PO2 chart on my primary handset for doing these flushes at less than max depth for cell validation. Using the O2 injection to solve hypoxia gives you an unknown gas until the cells can analyze it. Not good if you didn't put in enough or too much. I like instantaneous results in a potential hypoxic situation.

Sorry for the long post. It's a bit of reduction from a previous post of mine in this thread.

1st May 2008, 14:36	#37 (permalink)
mempilot What is this..terrafirma? Current Rebreather/s: Megalodon Other Rebreather/s: Megalodon Join Date: Aug 2006 Location: Ft. Lauderdale Posts: 1,179	Re: O2 slug Lance, You are spot on. IMHO, hypoxia is the more dangerous situation. I've experienced it in the altitude chambers, and it wasn't until watching the video of the event afterwards that I realized how f'd up I was and unable to do the simplest tasks. This is why I use the ADV for a @1.0 PO2 DIL flush at max depth. Breathing out while hammering the ADV and crossing the left arm over the CL's will push a lot of gas through the loop in an instant. Hammering DIL, even if not needed, will not kill you. The only time I use O2 manual injection is for flying manually for practice, finite bouyancy control in shallow water, 6m O2 flush, or after a solenoid failure. Like Lance, I believe there is plenty of time to deal with high PO2, such as the possible solenoid stuck on or manual gas bypass stuck on. These two problems are real obvious and very easy to deal with in a calm manner. Remember OC days? Roll the offending post off, right? Or, even easier if it's the MGBP valve: Remember the stuck drysuit inflation valve drill? Pop the hose off the valve for an immediate bandaid. Hyperoxic is a matter of dose and time. Hypoxia is a matter of just a few breaths. So unless one is conducting dives at up around 1.6 PO2 for very long periods of time, a spike above that can be tolerable while one deals with the situation prior to experiencing hyperoxic tox symptoms. As for handset and HUD monitoring: Absolutely important for all of this. "Know your PO2". And if we do all this right, hypoxia would be a huge mistake and so hyperoxia would be as well. So one has to look at the possible failures that could cause these problems and the solutions to them. Rebreather failures that impact PO2 are fairly easy to deal with if practiced and understood. Diver failures are usually the cause of hypoxia, and can be very difficult to deal with in the mental state the condition leaves you in. It can also be like walking off a cliff. One breath you are fine. The next breath you are incapicitated. I like having the ADV and known end result PO2 of using it to immediately put breathable gas into the loop. I also put a DIL PO2 chart on my primary handset for doing these flushes at less than max depth for cell validation. Using the O2 injection to solve hypoxia gives you an unknown gas until the cells can analyze it. Not good if you didn't put in enough or too much. I like instantaneous results in a potential hypoxic situation. Sorry for the long post. It's a bit of reduction from a previous post of mine in this thread. __________________ MEM "Da Pilot" Black holes are where God divided by zero. "If at first you don't succeed, don't dive silent." "Would you mind not shooting at the thermo-nuclear weapons." ~ Vic Deakins "Donkey's kill more people annually than plane crashes."
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