KevinNM
Contributor
They will work on an unconscious patient that is breathing spontaneously. A BVM is what you use if they are not. And a BVM is like 20 bucks.
Emergency oxygen: non-rebreather mask just as good as demand valve?
- Thread starter 2airishuman
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
The Demand Valves here also have a pressure valve (similar to a purge valve on your second stage) so they can be used to deliver 100% O2 to an unconscious non breathing casualty. They also have a pressure release valve so you can't over inflate. They really aren't that hard to use. I have taught hundreds of people how to use them effectively.
The BVM can also deliver 100% if you increase the flow rate to 15 lpm and have a reservoir bag attached. The advantage to them is you can "feel" the pressure required to inflate and gurgling in the airway. The disadvantage is that you use more O2 than the Demand Valve method where the gas only flows when it is being delivered to the patient.
Contrary to what the media likes to report scuba tanks and therefore equipment does not deliver Oxyen. Depending on the Gas mix the reg may be able to deliver a higher concentration of oxygen to the casualty. In a dive emergency the higher level of O2 is considered by experts to be vital to improve outcomes.
I understand the concern about being able to get O2 fills but I don't understand the $ issue. Why are people prepared to spend money on dive gear but not the equipment that may be the difference between a positive or negative outcome for someone in need?????
The BVM can also deliver 100% if you increase the flow rate to 15 lpm and have a reservoir bag attached. The advantage to them is you can "feel" the pressure required to inflate and gurgling in the airway. The disadvantage is that you use more O2 than the Demand Valve method where the gas only flows when it is being delivered to the patient.
Contrary to what the media likes to report scuba tanks and therefore equipment does not deliver Oxyen. Depending on the Gas mix the reg may be able to deliver a higher concentration of oxygen to the casualty. In a dive emergency the higher level of O2 is considered by experts to be vital to improve outcomes.
I understand the concern about being able to get O2 fills but I don't understand the $ issue. Why are people prepared to spend money on dive gear but not the equipment that may be the difference between a positive or negative outcome for someone in need?????
- Messages
- 17,334
- Reaction score
- 13,744
- # of dives
- 100 - 199
This is an important point. At 15 lpm continuous flow, even a fairly large oxygen tank like a 5L will last you only an hour. A more compact tank like a 2L or 2.5L lasts for only 25-30 minutes at 15 lpm. And that's for one patient. Considering that in the case of an incident there may well be two patients who should be breathing oxygen, and that getting EMS within half an hour to an hour isn't guaranteed in many locations, I'd like my oxygen to last as long as possible.
My EMS system (and every single one I know of) has banned demand valve systems. True professionals, highly trained people that used the gear on a regular basis, were causing lung injuries with them and they were removed here before I got my license in 2000. I have serious doubt that a scuba agency course is going to make people better at it than medical school.
- Messages
- 17,334
- Reaction score
- 13,744
- # of dives
- 100 - 199
How on can a demand system cause lung injuries? A positive pressure valve, sure, no doubt about that. And they are not supposed to be used by others than train medical professionals. But the demand systems I've encountered only deliver gas when the patient is breathing in, and delivers at ambient pressure. Basically the same way a normal reg set does. How can that cause lung injuries?
No snark or gotcha, I'm genuinely curious.
People were using the button, not letting the valve itself work on the old systems that our system had. The true demand set ups were never really popular because they didn't let us breathe for the patient like with an ambu bag. And they consequently, didn't make it into protocols past trials. While o2 supply isn't as big of a concern for us (an ambulance and fire engine can both hold a lot of bottles, and large ones) we have to worry about overall quality of care way beyond percentage of oxygen being administered.
Besides, 15lpm via nrb or ambu bag is capable of taking the vast majority of patients to 98% to 100% oxygen saturation. So while I understand the point of wanting the highest percentage going in, if I can get tge blood saturated to 100%, why try to go higher?
A healthy non smoker can achieve 100% blood saturation on ambient air. The body is designed to do that. When we inhale 21%, we still exhale roughly 14%. We don't even add supplemental oxygen for a patient until they're below 94% (that'll vary with different protocols from different med control)
OP
2airishuman
Contributor
BVMs and MTVs (manually triggered ventillators, think of a demand valve with a purge button) have a poor track record in actual use. Even highly trained professionals have trouble avoiding 1) overinflation of the lung, leading to lung overexpansion injuries and AGE, and 2) directing gas into the esophagus, unless an endotracheal tubeor other artificial airway is used.
Those are called MTVs in the DAN literature.
This is an important question worth discussing.
1) I'm not a professional or para-professional rescuer or an M.D. or nurse. I'm not an instructor or a dive operator. I'm just a diver. The DAN rescue kits including a demand valve start at $425--without a cylinder--and ones with an MTV start at $575. In my situation, this is an enormous amount of money to spend on standby safety equipment that will probably never be used.
2) I can make up a kit with a regulator and two non-rebreather masks in a ziploc bag for $12. If I shop carefully and take my time I can pick up a cylinder for $40 plus the cost of hydro and fill. The thing about this is that it's cheap enough that any risk of loss or theft no longer matters. I can leave it in the car, leave it on the beach, bring it on the sort of outings where it's impossible to supervise belongings the whole time.
3) I can make up 4 of these kits and leave them places as long as I select locations where the oxygen cylinder doesn't pose a hazard. Have one in every car, boat, lake place, give them to my dive buddies and kids. Low cost = high availability. Or I can bring two or more to guard against an incident with multiple injured persons.
It's far cheaper to bring two cylinders, or a larger cylinder, or some combination.
In the U.S., the standard cylinder for EMS use is an M15 or "D," which holds about 425 liters (15 cf) of oxygen. For long-term oxygen therapy in home or institutional settings, the most common is an M24 or "E", which holds 675 liters. DAN sells kits with various cylinder configurations ranging from a single M9 (240 l, 9 cf) to two jumbo M22 "D" cylinders (around 1200 liters overall).
I like the idea of carrying an emergency oxygen kit with a smaller cylinder that is ready to use, plus having one or more larger M24 "E" cylinders available nearby if necessary.
This has been a problem area with BVMs and MTVs (again, demand valves with a pushbutton trigger). I've read a bunch of the literature and have concluded that the safe and effective use of this gear is probably beyond my ability.
The problem isn't the demand valve itself, but the use of these systems in a manually triggered fashion. To some extent the breathing is then under control of the rescuer, and it is very, very easy to overinflate the patient's lungs.
The purpose of the high FO2 in DCS is to reduce the partial pressure of nitrogen in the inspired air, so that offgassing occurs more quickly.
OP
2airishuman
Contributor
