Portable CO monitor

[Patti Analox]

Hi manus,

Thanks for your questions and Don, as usual, really good answers.

We are lowering the bump gas to 10 ppm. Our Bump-It is a very low pressure, and now low ppm solution which can travel in your checked baggage only. To be fair, you may encounter ill-informed TSA (if you can imagine that) who may decide to seize your Bump Gas. It's doubtful, but stranger things have been removed from checked baggage.
The Bump test is only to make sure the sensor is working. In a pinch, our normal exhalation does include 1 ppm CO, which the EIICO does pick up...you see where I'm going with this.

Pricing in the US is low at the moment because of DEMA purchases being cleared through the marketplace. This is a once a year occurrence. Retail for this unit will be $379.00 USD in North American and comparable in the rest of the world.

 

[swamp diver]

How exactly does hyperbaric treatment of CO poisoning work? I mean what is the physiological mechanism? Does it actually help in the long term, or is it just a temporary aid? While a patient is under pressure, is there actually more O2 in their blood stream? It's not like the amount of hemoglobin is changing, whether or not said hemoglobin is permanently bound to CO, and I thought the amount of O2 carried dissolved in plasma was relatively small, so would a high PPO2 change this enough to be helpful?

Suprane's tutorial has been excellent but just to add the graphics here is a figure detailing how ambient and hyperbaric O2 can greatly increase the rate of CO elimination by the lungs.
http://www.coheadquarters.com/coremove1.htm

And the relationship between pressure and the amount of oxygen dissolved in the plasma.
http://www.coheadquarters.com/figco06.htm

One consideration not mentioned in determining the maximum concentration of CO accepted for recreational diving (5 ATA) is the level of exertion which greatly influences how quickly one will reach the COHb equilibrium concentration for a particular CO exposure concentration. If one looks at Table 4 below one can see that there is a time-concentration relationship but generally after three hours an equilibrium is reached for a particular CO exposure. For example, for a 25 ppm exposure at one hour the COHb concentration will be 1.5 percent but after 3 hours this will level out at 3.6 percent. It is important to remember that these COHb concentrations are for a person at rest. Increased exertion (i.e. swimming in a current) will result in one attaining that equilibrium concentration of 3.6 percent in much less time.

The WHO currently recommends that for the general population the COHb concentration be kept below 2.5 percent particularly in order to protect those with both known and occult coronary artery disease since COHb levels above this have been shown to induce angina and ECG changes indicative of coronary ischemia (lack of blood flow). The American Conference of Government Industrial Hygienists (ACGIH) have set their biological exposure index (BEI) for COHb set at 3.5 percent, that level below which there will not be any serious health effects in the worker.

Now attempting to determine a safe maximum CO exposure level for recreational diving including those divers with heart disease, of which there are many, one can synthesize this information to arrive at a suggested maximum concentration exposures.

One can see that for a 25 ppm concentration the COHb equilibrium concentration at rest after 3 hours will be 3.6 percent which is above both the WHO and ACGIH suggested maximum concentrations. It can also be shown that a diver/worker undergoing moderate to extreme levels of exertion at one atmosphere may attain this COHb concentration of 3.6 percent in under an hour.

So if a healthy diver with an effective surface CO concentration of 25 ppm is swimming hard in a current he/she may reach the ACGIH's BEI of 3.5 percent COHb at 5 ATA. Working back to a safe CO concentration measured at the surface one will arrive at 25 ppm/5 = 5 ppm for recreational air diving in the diver with no heart disease.

Any older diver or one with known coronary artery disease would want to remain below the WHO's maximum COHb concentration of 2.5 percent particularly if there was to be any significant exertion during the dive. This can be achieved by sticking to dives with minimal exertion, keeping one's ambient pressure exposure < 4 ATA, shortening the length of the dive, or the easiest method would be to reduce the CO exposure to 0 ppm in the compressed breathing air.

Both Britain and Canada have now set their maximum CO concentration for air diving at 3 ppm in order to protect the most CO-sensitive individuals in the diving population.

 

[swamp diver]

Hi manus,

Thanks for your questions and Don, as usual, really good answers.

We are lowering the bump gas to 10 ppm. Our Bump-It is a very low pressure, and now low ppm solution which can travel in your checked baggage only. To be fair, you may encounter ill-informed TSA (if you can imagine that) who may decide to seize your Bump Gas. It's doubtful, but stranger things have been removed from checked baggage.
The Bump test is only to make sure the sensor is working. In a pinch, our normal exhalation does include 1 ppm CO, which the EIICO does pick up...you see where I'm going with this.

Pricing in the US is low at the moment because of DEMA purchases being cleared through the marketplace. This is a once a year occurrence. Retail for this unit will be $379.00 USD in North American and comparable in the rest of the world.

That is great news regarding the bump gas concentration but having looked into how to get this onto a commercial flight previously I was told that the aerosol pressure would have to be stamped on the can and should be below 25 psig. I'd even make the label say "compressed air with 10 ppm CO" so that the TSA people think it is a can of air to clean a camera, etc.

The breath concentration in a non-smoking individual in CO-free ambient air can be as high as 4 ppm. I know mine runs consistently at 2 ppm and my secretary who smokes runs at 9 to 10 ppm. Don't lie on your life insurance forms regarding smoking as the insurance companies are on to this and will show up at your house with a breath CO analyzer.
Does breath carbon monoxide measure nicotine depen... [J Addict Dis. 2010] - PubMed result

To use the EIICO for breath CO analysis take a deep breath and gently blow into the larger hole on the "side" of the sensor dome rather than the pin hole where one flows the compressed air into. It is quite interesting how stable one's breath CO concentration is as long as not sick (i.e. a cold) or walking around in a room full of smokers.

Our body produces and releases carbon monoxide, hydrogen sulfide, and nitric oxide all of which are gaseous neurotransmitters and can be measured in the breath.

 

[manus]

Suprane & Swamp Diver, precious information, exactly what I was looking for, more medicine-related studies. This material can be used to start sensitizing students and certifying diving organisations.
Really Thanks :thumbs-up

 

[swamp diver]

3) Why the units on the European market costs almost the double of the US market ??? Patti, do you plan to present the EIICO to some European diving shows, with some more convenient prices ?

Thanks and safe diving !

You could still order the unit at the lower price from ScubaToys in the US or from Dan's Dive in Canada. The US and Canadian dollars are currently at par more or less.

Scuba Gear and Dive Equipment with reviews on sale


https://dansdiveshop.ca/store/index...fa9302a5c0289dd1e0d71&keyword=carbon+monoxide

 

[CriticalMass]

Here's a question for the more experienced CO tester users -

It occurs to me that, depending on the wind, it would be easy to get a false positive when using a CO tester on a boat. What's the best strategy to avoid that, assuming fresh tanks are already on-board?

 

[DandyDon]

Here's a question for the more experienced CO tester users -

It occurs to me that, depending on the wind, it would be easy to get a false positive when using a CO tester on a boat. What's the best strategy to avoid that, assuming fresh tanks are already on-board?

I prefer to read before leaving the dock, gives a chance to do something about bad tanks, and less likely to have an accident like when I dropped my analyzer in the ocean while on a moving boat.

Depending on the unit tho, you blow tank air thru it, or bag it, so air is not much of a concern.

 

[Patti Analox]

Hi Critical Mass and Dandy Don,

We've addressed this very issue in a soon to be released manual update: Bottom line is it's easiest to check tanks at the dock, but for trip fills, we offer the following:
SAFETY WARNING
It is of vital importance that the zero calibration is performed with a source of clean air. Just
because a calibration is performed in the open air on board a boat it should not be assumed
that the air is clean. Due to backdrafting, or the 'Station Wagon' effect, accumulation of
carbon monoxide can occur in the cabin or aft deck, even in an open area.
Air flow
Low pressure
area created at
rear of boat
pulling exhaust
fumes back in to
the boat

This effect occurs as air moves around a boat and forms a low pressure area behind it that
tends to pull exhaust fumes back into the boat. If the EII CO is calibrated using this already
contaminated air it will result in false gas tank measurements. Users should be aware of this
and should take appropriate measures to ensure a clean air source is used when performing
a calibration as the accuracy of the measurement of the breathing air tank is only as accurate
as the initial calibration.
The risk of air contamination does not only exist when the boat is moving at speed, it can also
be encountered with the boat moving at slow speed or idling. The air in your boat can also be
contaminated by another vessel&#8217;s exhaust that is alongside and even if you are moored near
another vessel.
To ensure the accuracy of the calibration the following should be considered:
1. Check the contents of your gas cylinders before boarding the boat
2. Use a known clean source of air to pass a flow directly over the sensor using the push-in
calibration adaptor
3. Calibrate the EII CO using the zero calibration kit (see section 3.3) Essentially flush the unit with a KNOWN zero gas (even a pony tank tested and known safe prior to your trip.) Use this to ensure the sensor is exposed to no CO if you have to perform a zero cal on the boat.

So, where you are on the boat matters.

 

[DandyDon]

Ah precheck calibration, ok. My unit came in after the blizzard delay, but I have not been to town for it and started working with it. Forgot.

As a remind, use that wrist strap. My daughter broke a camera not using hers, I've dropped an open one in a rinse bucket once as well as my other CO tester overboard - caca happens.

 

[suprane]

Here's a question for the more experienced CO tester users -
It occurs to me that, depending on the wind, it would be easy to get a false positive when using a CO tester on a boat. What's the best strategy to avoid that, assuming fresh tanks are already on-board?

The unit I use (ToxiRae 3) has an adapter that plugs into the BC inflator hose with a tube coming off of that to the snap-on calibration connector of the CO monitor. When you open (turn on) the regulator you get a constant 2 lpm flow through the orifice of the BC adapter. This should be more than enough of a flow rate to prevent any back-flow of ambient air into the sensor chamber.