Oxygen Administration Skills- Did I miss something (like demand valves comin' back?)

[medic_diver45]

How come every dive book I have seen, when it discusses O2 administration has it being given through a demand valve (aka Elder valve) type system? See page 154 of the PADI open water dive text for an example of what I mean. These are dangerous devices (if you aren't d--n careful with them (and really experienced with them- more than you're gonna get from a simple class (I don't trust doctors (except maybe anesthesiologists) with them let alone a first aider)) you can easily added a ruptured and collapsed lung (barotrauma induced pneumothorax) to the patient's list of problems.

That is not to mention that these setups waste lots of O2; you will get further with a non-rebreather mask, or if the patient isn't breathing an AMBU bag. Just my professional medical opinion but we pulled them off the ambulances around here in 1998/99 (I actually think the state of Indiana now lists them as unsafe for prehospital use by TRAINED EMT's and PARAMEDICS- at least that's what I was told).

Is there evidence (peer-reviewed medical journal articles, etc) that contradicts everything I have been taught by stating that it is SAFE AND EFFICACIOUS (spelling?) to put these devices into the hands of untrained persons (face it, no matter how much PADI wants to think that the program might prepare someone to use a demand valve, a few hours of training doesn't cut it). I hope it's just that the pictures in the book haven't been updated in a while (for the patients' sake).

 

[lamont]

Are you talking about a demand valve in a spontaneously breathing patient, or are you talking about a manually triggered ventilator instead of rescue breathing in a non-breathing patient? With just a vanilla demand valve I don't see how you get barotrauma since you're not forcing air into the lungs...

I know that in the DAN curriculum the basic O2 administration course only teaches demand valve, non-rebreather mask and rescue breathing with supplimental O2. The advanced O2 course teaches bag valve masks (with and without O2) and manually triggered ventilators.

I'm curious about any responses since I just took the advanced O2 course last night....

 

[Fly N Dive]

lamont i'm with you, not sure how you could get barotrauma from using one.
i took the DAN O2 course this summer and have breathed off of one of these, its like the valve in the 2nd stage of your reg.
medic diver are you talking about one of those positive presure units? and not the demand one?

 

[Skip Parker]

Yes, I believe medic_diver is a bit confused. Probably because of a difference in terminology between industries. The demand valve divers use cannot deliver air to a non-breathing patient, unlike the Elder valve he is describing.

medic, the valve you are discussing is only used for Advanced O2 Provider training. The valve you are seeing in the manuals is not power assited. It is essentially the same as a scuba/scba second stage.

 

[medic_diver45]

Apparently there is some miscommunication here; I have NEVER seen a demand valve that freely flows O2 (Although I was told they were in use in the 50's and 60's on board ambulance, before plastic masks became widespread) ....I have seen only the variety that you use to forcibly ventilate a patient with (the one that is dangerous because of a lack of an ability to "feel" how compliant/responsive the lungs are) These should NOT (REPEAT NOT) be used by any one unless you are INTIMATELY familiar with them (and I mean like you have had professionally training in medicine) and even then they are still fraught with danger. I am far more experiencer than the average person (since I deal with ventilating people for a living), and given the choice between using a demand valve and doing mouth to mouth on a person, I'd go with doing mouth to mouth any day of the week. At least that way I wouldn't risk causing more problems.....if the patient ain't breathing, he's already got enough of those. I can't understand why they still teach the use of such an archaic device as this......

As for the free flow variety of "demand" valve, I don't understand why you would shell out large sums of money to do something that can be done with a $2.50 non-rebreather, not to mention that with a NRB you don't have to hold in on the patient's face. Sounds like who ever is marketing this equipment to divers is making a serious killing peddling a piece of eqiupment that is unnecessary.



To put together a fully stocked O2 kit (a stripped down version of what I have in my personal vehicle) you would need:

Oxygen (minimum of a "D" cylinder, preferably a "Jumbo D" or "E" would be better") Source: Welding supply company (that's where most ambulance services get theirs from) Cost: $40-60 depending on location

Oxygen regulator- $90-100 (you can buy them from medical supply catalogs; here's where I got mine www.buyemp.com

CPR Barrier Mask w/ O2 inlet- $15 or a Bag-valve-mask device $15

Non-rebreather mask- about $2.50 (always a good idea to carry at least two of them


TOTAL COST: about $200.00 tops, and that's if you include a bag to put all of it in (the one's designed to carry O2 run about $25.00 and up)

No need to waste several hundred dollars on an expensive outdated piece of equipment. You get just as high, if not higher, 02 concentrations from a NRB as you do an demand valve and it is much more comfortable for the patient.

 

[Skip Parker]

Apparently there is some miscommunication here; I have NEVER seen a demand valve that freely flows O2 (Although I was told they were in use in the 50's and 60's on board ambulance, before plastic masks became widespread) ....I have seen only the variety that you use to forcibly ventilate a patient with (the one that is dangerous because of a lack of an ability to "feel" how compliant/responsive the lungs are) .

You're still a bit confused. The demand valve does not free flow O2. Nor does it forcibly ventilate a patient. As I mentioned it works like a second stage. I.E. when the patient inhales, it uses a diaphram or other method to open a valve allowing the O2 to flow. Thus the use of the word valve. It does not have the button to manually release the O2. I believe that's called the MTV-100 valve.

The demand valve only release O2 on an inhale, makeing it much more efficient than the non-rebreather mask, without the dangers of the power assest mask.

 

[medic_diver45]

OK, I stand corrected on the workings of this type of demand valve (I only knew of the Elder-style demand valve).....the terminology is kind of screwy and threw me. Still I don't think the need to buy an expensive piece of gear is justified, when the purpose can be served just as well with less expense. I don't know many people who can afford to blow $500 on a piece of equipment, that in all likelihood would (hopefully) never have to use. It's whole lot more cost effective to buy an couple of NRB's, a pocket mask (or Bag-Valve-Mask), and rent (usually the gas supply stores don't set a date by which you have to bring the tank back) two (or even three) "D" cylinders of 02. At 15 liters per minute on a NRB, a D tank will last 15 minutes and an "E" cylinder will last about 20-25 usually (these are ballpark figures, if anyone truly cares I can get the specific figures for you). You spend less money and get the same effect. Do you see my point here?

I still think the reason why the demand valves are so widely featured in diving materials is so that DAN can turn a tidy profit with the sale of these overpriced antiques (they are probably the only piece of "dive" gear in use today that is essentially the same as what was used in the 1950's). I can think of no other reason.

 

[Skip Parker]

OK, I stand corrected on the workings of this type of demand valve (I only knew of the Elder-style demand valve).....the terminology is kind of screwy and threw me. Still I don't think the need to buy an expensive piece of gear is justified, when the purpose can be served just as well with less expense. I don't know many people who can afford to blow $500 on a piece of equipment, that in all likelihood would (hopefully) never have to use. It's whole lot more cost effective to buy an couple of NRB's, a pocket mask (or Bag-Valve-Mask), and rent (usually the gas supply stores don't set a date by which you have to bring the tank back) two (or even three) "D" cylinders of 02. At 15 liters per minute on a NRB, a D tank will last 15 minutes and an "E" cylinder will last about 20-25 usually (these are ballpark figures, if anyone truly cares I can get the specific figures for you). You spend less money and get the same effect. Do you see my point here?

Not exactly. In your world, O2 is plentiful. When diving, you are likey 20 minutes off shore with just a small boat sized O2 bottle. The non-rebreather is wastefull of that O2. Also the commony accepted treatment for DCI is 100% O2, which only the demand valve will give.

 

[lamont]

So, I don't think that the MTVs are the same as the ones that were around in the 50s. The modern ones only allow a flow rate of 40 lpm. They also have an overpressure relief valve set to 60 cm H2O. Part of the Adv O2 course is training to test the OPV. You're also trained not to fully inflate the lungs and to watch for forcing air into the stomach.

If the lungs dont inflate because of obstruction or FUBARness beyond the abilities of first responders to fix, then the OPV wont let you overpressure and barotrauma anything. If the lungs do inflate, you're trained not to overinflate, and the equipment should prevent you from overinflating.

That doesn't seem that bad. Granted I only got trained last night and have never had the opportunity to do it for real, but barotrauma would only seem to be able to result from equipment malfunction combined with procedural error.

It seems to me the biggest problem with the course is lack of airway management techniques -- all that is taught so far is head tilt. If the airway isn't open the issue isn't so much barotrauma but that the equipment is useless -- but in that case so is rescue breathing. So, this is really a criticism that I have of all the first responder / CPR courses. Nobody teaches you how to deal with something as simple as vomit...

I'm taking the DAN BLS course on saturday which will cover more airway management and stuff, but I doubt that's really sufficient training either. I'd like to take EMT training, but that isn't really compatible with an already 50-60 hour work week (at least not if I ever want to have some time to go diving...).

 

[medic_diver45]

Ummm.....nothing gives 100% O2 unless the patient has a breathing tube in place....there is always leaks of some sort... you may get FiO2 (fraction of inspired oxygen) up around 80-95%, but that's the same as you get with a well fitting non-rebreather.

Another point, remember I am an EMT in a rural part of the country (where it may take almost an hour to get an ambulance to the scene) so I know how precious O2 is....That's why I carry at least 2 (sometimes 3) "E" cylinders in my truck at all times.

I think if a boat is big enough to carry six (or more) divers and their gear, then there's more than enough room to stick a couple of "E" cylinders (they are not that bulky for crying out loud). They take up about the same amount of space as an 80 cubic ft dive tank. If you're that concerned about running out of O's then you should be carrying more than just a "C" cylinder like DAN sells. Especially in places (read: overseas) where the emergency services are less than optimal and may show up late (if at all). This is even possible here in the US- remember most emergency services nationwide are provided by volunteers, so you may only get one or two people who respond in their private vehicles....not the cavalry you were expecting, huh?

Besides since we're debating oxygen consumption here, take this worst case scenario into account (which is what you should do when planning anything): suppose your patient has taken a big hit, and is hyperventilating, even a demand valve is going to not limit his eating up the tank. Since you're comparing it to the second stage on a dive tank, we've all seen people panic and suck a tank dry real quick. That "C" tank doesn't stand a chance......just my humble opinion as a medical professional. I don't mean to be condescending or anything, I am just trying to look at what you are saying from all sides.