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

[medic_diver45]

. The modern ones only allow a flow rate of 40 lpm.

Let's see; there's a thing called minute ventilation: Volume of each breath x respiratory rate = MV.....basically how much air you are moving in one minute in liters. If you are taking a 1000 mL tidal volume (a fair approximation of a large gasping breath) and the patient is breathing, say, 50 times per minute (which is not uncommon in patients who are critically ill especially with insults to the brain or lungs (air embolism)), that means they are moving more than your little valve will allow.....does it allow them to over breathe?

Even if they are only pulling 40 L/min (which is not an unusual minute ventilation for a critical patient in frank distress), on a "C" tank (aka "the little dive boat tank") that only gives you (assuming the tank has a working pressure of 2200 psi and is full when you start) about 4.4 minutes before that tank is dry. If you have a "D" tank and use the demand valve, you've only got 8.8 minutes. Sounds like it's buying you a whole lot of time to me.

Yes NRB's waste a lot of O2, but not that much more than a demand valve. But if you have a full "D" tank on at 15 L/min, which will give around 70%-90% O2, which is about as good as it gets in the field, you have 23 minutes of time before the tank goes dry.


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.

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

Couple of points, One: lung barotrauma can happen at pressures as low as 30 mmHg (40 cmH20) (if you care to read it for yourself: p. 884 Egan's Fundamentals of Respiratory Therapy, 7th edition). If you have a patient that has some sort of a lung injury....say they held their breath on the way up and popped a lung....now they have a pneumo and that pressure you're giving them is making it worse....

Two....like I said before, a couple of hours training doesn't make you an expert, or really even very knowledgable about how to ventilate someone. Most doctors I know screw up and overventilate and hyperinflate. It's due to the stress of the situation....nothing to be ashamed of, just something you have to watch out for. Cases like this are prime examples of where a little bit of knowledge can be a dangerous thing.

Most people are trained to stop ventilated once they see the chest start to rise.....well in some people that works, and in others it takes a lot of pressure to move the chest wall (such as fat people) and the lungs are already inflated long before the chest wall begins to move. If you want to argue pulmonary physiology and oxygen administration techniques, you picked the wrong person to do it with. Remember it's my job to know this kind of thing inside and out. I don't mean to be crappy, I just want everyone to be on the same page and have their facts straight.

 

[gjmmotors]

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.<snip>

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,

Well If your patient/victim is hyperventilating I was under the assumption of the NREMT standards to use a BVM to assist breathing and to help control the hype. I go for my recert this year it may have changed.
Medic_diver45, I have looked at the DAN stuff and the PADI EFR, its very layperson oriented. It also assumes you have the bare minimals at the site. DAN pushes the use of the stuff they sell,(rebreather, kits etc).
The aforementioned regulator, something along the lines of a FROP-VD, is different from the "Cop Poppers" that were taken away due to people(mainly cops and emt's) holding the manually triggered device and "cop popping" lungs.
A non rebreather is standard on ambulances and the like, and is the most simple and stupid proof thing out there, but if the industry will support the purchase of big dollar demand valves that s what we will be seeing.
-g mount

 

[medic_diver45]

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...

Actually barotrauma is fairly common even amongst professionals (rates ranges from 10-44% in the studies I am aware of), so imagine what the rate is going to be with a scared, stressed, out-of-practice rookie.

Without training on how to intubate (insert breathing tubes), other than the head tilt chin lift, there is very little else that can be done even by a Basic EMT (I'm an Intermediate EMT and have been trained to intubate in addition to being a respiratory therapist.) If the airway doesn't open with that, you just have to keep trying.....one mistake that a lot of people make is they tilt the head back too far. You can just put a rolled up towel under the neck, and that usually is enough to keep an open airway (just check to make sure though).

To deal with vomiting, roll the patient on their side and sweep out their mouth with your fingers or a piece of cloth.

 

[medic_diver45]

Well If your patient/victim is hyperventilating I was under the assumption of the NREMT standards to use a BVM to assist breathing and to help control the hype. I go for my recert this year it may have changed.

Have you ever tried to hyperventilate a conscious patient? It doesn't work. If they are unconscious and hyperventilating, then the problem of barotrauma becomes even more of an issue if you start to try to hyperventilate. Basically they are breathing so fast that they don't have a chance to exhale and then you try to force even more air down there.....you get the idea. The books say to hyperventilate, but it's usually not feasible. If they are moving adequate volumes of air....then don't mess with them, put a NRB on them and haul A--.

Medic_diver45, I have looked at the DAN stuff and the PADI EFR, its very layperson oriented. It also assumes you have the bare minimals at the site. DAN pushes the use of the stuff they sell,(rebreather, kits etc).

Of course they do.....otherwise why bother having a course....LOL

A non rebreather is standard on ambulances and the like, and is the most simple and stupid proof thing out there, but if the industry will support the purchase of big dollar demand valves that s what we will be seeing.
-g mount

I'm gonna see if I can't rally some support from the different professional societies (AARC, ACEP, NAEMT, etc) to try to change that....It's a little ridiculous that DAN is so far behind the times on something so simple.

 

[medic_diver45]

I mean people raise hell about this DIR debate....."lemmings" this and "cult followers" that, but no one thinks to question DAN on something like this? That just seems a bit odd to me. I mean they are great resource if you get bent.....but they shouldn't be recommending equipment that trained medical professionals have problems with for use by first aiders.

 

[gjmmotors]

I'm gonna see if I can't rally some support from the different professional societies (AARC, ACEP, NAEMT, etc) to try to change that....It's a little ridiculous that DAN is so far behind the times on something so simple.

What scares me are the people teaching the classes are just people that took the basic class, then became a dive instructor or decided to become a EFR or DAN type class instructor.
When I did my EFR instructor class, i was scared. I walked out a few times even. I couldnt believe they were training a layperson to be able to instruct another layperson.
This one time I had a PADI EFR push me and another person out of his way because he knew how to handle the situation.( He announced "get out of my way im a PADI EFR and I am trained to assist") I was assisting a Doctor with the accident, but thats another story for another time.
-g mount

 

[medic_diver45]

That is frightening.....He would have gotten shoved right back. Unless you're a doc or another medic, then don't get between me and the patient. Even if you are a doc or a medic....don't get pushy....times like that are not where you want to be a glory-hog. I welcome all the help I can get, as long as you're not in the way.

 

[medic_diver45]

I would like to say that I hope no one on here gets the impression that I am arrogant, egotistical or anything like that. It's just that I look out for my patients' best interest at all times (including before they become patients). I want them to recieve the same standard of care I would want to have if I were the patient. I don't meant to degrade anyone or their abilities, I just everyone to be realistic about their limitations and knowledgable about what they are working with. You wouldn't jump in the water with a second rate dive computer ....why rely on an oxygen system that isn't the best you can have. Both can save your life, but only if you how and when to use them.

If I offended anyone, I am sorry, that was not my intention. It's just I take my job very seriously and this is my job- I defer to the more experienced amongst you all when it comes to areas of diving for which I have no experience, I just ask that you do the same (or at least take what I am saying with a grain of salt (sea salt if you like)).

 

[Fly N Dive]

Couple of points, One: lung barotrauma can happen at pressures as low as 30 mmHg (40 cmH20) (if you care to read it for yourself: p. 884 Egan's Fundamentals of Respiratory Therapy, 7th edition). If you have a patient that has some sort of a lung injury....say they held their breath on the way up and popped a lung....now they have a pneumo and that pressure you're giving them is making it worse....

just a question, is this still about the demand valve? bc atleast the one in the DAN O2 kit doesnt force any air into the lungs, you have to breath it in. if this isn't about the valve please ignore this post

 

[medic_diver45]

just a question, is this still about the demand valve? bc atleast the one in the DAN O2 kit doesnt force any air into the lungs, you have to breath it in. if this isn't about the valve please ignore this post

Well there apparently are two of them (at least from what I am gathering from what I have been told): one for the basic O2 course that just flows and one (the Elder valve) which can be used to ventilate a patient that is for people who have been through the "Advanced" O2 course.

I am against both of them as I feel that the first one is simply too expensive for what it does (compared to what other options are available) and potentially wasteful of oxygen and the latter is dangerous because of the risk of barotrauma and simply because it is no longer considered the preferred method for ventilating an apneic (not breathing) patient- most states have removed (and/or banned them) from ambulances due to the risks involved and the existence of cheaper, safer, and more effective ways to ventilate a patient.

There are also sundry other reasons these devices are not appropriate (excessive weight compared to comparable devices (although I will admit it that it's not exactly excessively heavy), potential maintainence complications (one more thing to break down just when you need it), etc. There are simply better alternatives is all I am trying to point out, pure and simple.