Ronda Cross Tank CO Test cause of Death

[Aguablanco1]

Since we are planning at least two weeks of diving this year, all off shore, I have decided to purchase the Analox CO analyzer. Not bad at $285.00 shipped. After reading this, and other threads, regarding CO it seems the prudent thing to do. I would much rather err on the side of caution. Thanks for all the great info in this thread.
RichH

 

[DandyDon]

John,

note that the pp of O2 (and any other gas present in the mix) will be multiplied by 5 as well, so the respective binding propensity (or whatever you want to call it) of the different gas present in the mix will not change. In other words, if 10 ppm of CO at 1 ata is OK IN THE PRESENCE OF AIR as the diluent gas, 50 ppm of CO at 5 ata will have the same effect IN THE PRESENCE OF THE EXACT SAME AIR FRACTION.
It is a competition thing. 1 big guy against 10 tiny ones will have the same effect as 5 big ones against 50 tiny ones.

And, in addition to John's answer - on ascent, PPO2 drops while CO largely stays bound, blocking O2. Well, there are good reasons for 10ppm limits, 3 to 5 in some other countries. There should be no CO getting in the tank, so if I find any at all, I'm going to wonder what else they are doing wrong to the air I breath.

Since we are planning at least two weeks of diving this year, all off shore, I have decided to purchase the Analox CO analyzer. Not bad at $285.00 shipped. After reading this, and other threads, regarding CO it seems the prudent thing to do. I would much rather err on the side of caution. Thanks for all the great info in this thread.
RichH

Good plan. It gets boring checking each and every tank if you get all zeros like you should, until you finally get a ready - and then it all became worth the time, trouble, and money. I've had significant readings in 3 countries just from my dive travels and I still get bored with the testing at times.

 

[uwxplorer]

Some real physiology expert would be well inspired to clarify a lot of misconceptions indeed.
This being said, I have a CO analyzer myself, whether or not I subscribe to internet theories or not.
This reminds me I need to order a replacement bump kit.

 

[NAM001]

Where do you get your bump kits from?

some real physiology expert would be well inspired to clarify a lot of misconceptions indeed.
This being said, i have a co analyzer myself, whether or not i subscribe to internet theories or not.
This reminds me i need to order a replacement bump kit.

 

[DandyDon]

Guys, try blowing on the sensor. Remove the flow restrictor, zero the dial, blow a full breath, and look quickly. I bet you get a reading.

 

[uwxplorer]

Where do you get your bump kits from?

I bought one from the dive shop I purchased my analyzer from, but they had to special order it, so I guess I will go ahead and order directly online.
The product is here: http://www.gascogas.com/bumpit.html, 10 ppm CO.

Edit: Note the 10 ppm specification! I have seen a CO Gasco bump kit rated 50-100 ppm. That is NOT what you want to blow into a Scuba gas analyzer who is looking for things above 5-10 ppm!

 

[John C. Ratliff]

Guys, try blowing on the sensor. Remove the flow restrictor, zero the dial, blow a full breath, and look quickly. I bet you get a reading.

DandyDon and Swamp Diver,

I have to back away from my statement about the body not producing CO. I have found the first source which explicitly states that the body does produce a very small amount of CO, the U.S. Navy Diving Manual, 6th Edition (2008):

3-5.8 Carbon Monoxide Poisoning. The body produces carbon monoxide as a part of the process of normal metabolism. Consequently, there is always a small amount of carbon monoxide present in the blood and tissues. Carbon monoxide poisoning occurs when levels of carbon monoxide in the blood and tissues rise above these normal values due to the presence of carbon monoxide in the diver’s gas supply. Carbon monoxide not only blocks hemoglobin’s ability to delivery oxygen to the cells, causing cellular hypoxia, but also poisons cellular metabolism directly.

I would like to point out that what I state are not "internet theories," which is why I use my real name and titles, and produce the references. When I am skeptical, it is because I want to see the references, and ensure that they are accurate.

John (SeaRat)
John C. Ratliff, CSP, CIH, MSPH

 

[swamp diver]

DandyDon and Swamp Diver,

I have to back away from my statement about the body not producing CO. I have found the first source which explicitly states that the body does produce a very small amount of CO, the U.S. Navy Diving Manual, 6th Edition (2008):

I would like to point out that what I state are not "internet theories," which is why I use my real name and titles, and produce the references. When I am skeptical, it is because I want to see the references, and ensure that they are accurate.

John (SeaRat)
John C. Ratliff, CSP, CIH, MSPH

Good to see that you have updated your files on the body's endogenous production of CO.

Here is a good summary on some of the physiological processes for which the signaling molecule is CO. Adding in an external source of CO can severely disrupt those critical physiological systems such as blood pressure or oxygen sensing.
http://pharmrev.aspetjournals.org/content/57/4/585.full.pdf

You should investigate hydrogen sulfide (H2S) too because we make that toxic gas as well.

 

[John C. Ratliff]

Good to see that you have updated your files on the body's endogenous production of CO.

Here is a good summary on some of the physiological processes for which the signaling molecule is CO. Adding in an external source of CO can severely disrupt those critical physiological systems such as blood pressure or oxygen sensing.
http://pharmrev.aspetjournals.org/content/57/4/585.full.pdf

You should investigate hydrogen sulfide (H2S) too because we make that toxic gas as well.

Actually, it is not possible to be "up to date" on everything, and this old vintage diver has tried to do so in many areas. My main expertise is in industrial hygiene, where I have been investigating hearing loss and the effects of noise on workers. In this area, reactive nitrogen species (such as NO) is a metabolite of high noise levels, and research shows that this happens intra-cellularly. The effects of high noise such as IED explosions can cause hearing loss by destruction of hair cells inside the cochlea days after the event, and researchers are now looking at using anti-oxidants as a possible prevention after the fact of noise-induced hearing loss. However, my first introduction to human physiology has to do with diving, which I began in 1959. I became a NAUI Instructor (#2710) in 1973, and have published several articles on diving. I do know how to research things, and if I am challenged such as the information you gave me, I tend to respond by saying that it is interesting, but I want to find more before acknowledging the new information.

I have now found an even better reference, one that gives the normal levels of CO, which shows that "The normal endogenous production of carbon monoxide is sufficient to saturate 0.4-0.7% of the body's haemoglobin--that is, 0.4-0.7% carboxyhaemoglobin, at rest, but that a national survey in North America found 1-2% carboxyhaemoglobin in urban nonsmokers as a result of environmental exposure and 5-6% in smokers (cigarette smoke contains about 4% carbon monoxide)..."
Carbon monoxide poisoning
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2544692/pdf/bmj00267-0003.pdf

So my contention of environmental CO being a main cause is still valid, although there is some production by the human body. Note that the level of carboxyhaemoglobin is not directly related to the ppm in the exhaled breath, but the reference by swamp diver showed normal healthy people exhaling about 1.8 ppm. There were 13 control subjects in a study, but no reference to whether there was environmental CO--assumed not (Wu and Wang, page 608).

John
John C. Ratliff, CSP, CIH, MSPH

PS--I like your reference; thanks!

 

[uwxplorer]

Internet theories are bits and parts of perfectly legit information from the scientific or technical literature posted more or less out of context and absorbed, misinterpreted and disconnected by random readers with no appropriate scientific/technical background.
This is nothing addressed against you or your specific posts, but a warning that in an accident thread, posting on a rather complex topic of physiology in which research appears still active and experts confess a relative ignorance of many mechanisms (search the Rubicon archives for 'CO' for instance) might be double-edged.

My post was just stating a basic physical reality hinting at the fact that pCO cannot be considered alone. A pCO that would be fine in open circuit could kill you on a rebreather, for instance.

I applaud your active literature research, BTW!