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Three Letters Re: Welding Oxygen Versus Medical Oxygen
Jim,
I write to you again as I pull another EMS duty shift. So far tonight I have
had one EMS call and it was a "difficulty breathing" call. Our local
law enforcement officers (LEOs) already had the patient on 15LPM.
of 02 via
non-rebreather mask (NRBM)
before we got on scene. The LEOs tend to over inflate, so I titrated
the flow
down to 8LPM., which worked for the patient's breathing pattern. I'm glad
our LEOs are proactive, but this means that I don't get a baseline Room Air
(RA)
02 saturation for comparison and it does waste some O2 until I get there.
Hint: We use NRBMs on
the rig because from this one type of mask you can make the other types simply
by removing the circular rubber flap valves. The NRBM
has one inspiration valve at the top of the bag inside the mask; and two other
expiration valves outside the mask on each side of the nose. When you exhale,
the side expiration valves open allowing exhaled air and CO2 to escape outside
the mask. But when you inhale, these same valves close, and the inspiration
valve opens, allowing 100% O2 to enter the mask from the inflated bag. Hence
the name non-rebreather mask because the patient is not re-breathing his own
exhaled air. There is no outside air entrainment (provided the mask has a good
seal).
1) If you take the same NRBM mask and remove one or both of the expiration
valves from the side of the nose, you now have a partial rebreather mask, since
when the patient inhales, 100% O2 from the bag is mixed with room air from
the removed side valve port.
2) If you take both side valves off, and replace the bag O2 port with the straight
line O2 port (that is included in the NRBM package), you now have a simple
mask.
3) Here's another trick, if you take the straight line O2 port off the mask,
and replace it with the bottom medicine cup of a nebulizer, you have a aerosol
mask for administering nebulized medications like albuterol sulfate.
As more air entrainment is allowed, the overall O2 percentage decreases from
the 100% @ 8LPM. - 10LPM. of the NRBM to approximately 28% @ 2LPM. O2 of the
nasal cannula. It doesn't mean your wasting O2 by using a nasal cannula, (since
it uses a lower flow rate) your just choosing the best modality to meet the
patients need. Some chronic Chronic Obstructive Pulmonary Disease (COPD) patients
breathing drive can actually be suppressed with too much O2 over a period of
time.
(I've got to go, just got paged for an "Alcohol Overdose").
Now I'm
back again. The overdose call went okay. But I'm reminded that masks are
also good for combative, spitting, or TB patients
(Mask the patient and yourself) But on a sad note I found out that the patient
I transported three hours ago with difficulty breathing died of respiratory
arrest in the ER.
She didn't seem that bad, but she had a DNR order
and the family requested she not be intubated. I volunteer for this.
Regarding O2 itself. Almost all O2 manufacturers use the Air Liquefaction method
to make compressed O2 gas. The method is written on the side of the cylinder.
This is why you will see large stand tanks of Liquid Oxygen (LOX)
at the gas vendors' sites. The oxygen that boils off the LOX is piped through
a manifold
system to fill the cylinders usually on a cascade system. So although O2 USP has
the same basic source as industrial gases, it's specified., handled, distributed
and tracked differently. O2 USP has FDA mandated
lot numbers to facilitate product recalls. These lot numbers are tracked all
the way to the patient.
During the day I'm a Home Medical Equipment Technician in the respiratory department
of a major hospital. We jokingly call the hospital room
console the "magic" wall since compressed air, power, suction, O2,
etc. is right there. But the fact that O2 is flowing through a humidifier bottle
doesn't instantly change it to medical O2 as the previous supplier quote asserts.
It just adds humidity, and then really only at flow rates over 3LPM. Water
bottles are mandated in the hospital setting, but not in the home setting.
Oxygen is a natural drying agent. We do however use extra dry grades of O2
USP 99.995% and Nitrogen to calibrate our O2 analyzers.
A note on carbon monoxide poisoning. If the patient presents with the classic
cherry red complexion, they are too far gone for any O2 to do much good. The
carbon monoxide molecule binds something like 600 times more readily to the
hemoglobin in the blood than O2, and has to be forced out by O2 in a hyperbaric
oxygen chamber. Under double atmospheric pressure even the plasma in the blood
carries oxygen. (Which might be one reason our Pre-Flood forefathers could
run so
far and not become weary.) - Steve P., EMT in
Wisconsin
Mr. Rawles:
This is in regard to the oxygen discussion. I don't know the slightest thing
about the sources of oxygen, but as a nurse, I thought I would share a little
bit about administration of oxygen. The following is straight from my Medical-Surgical
Nursing textbook
" Indications for use: ...Oxygen is usually administered to treat hypoxemia
(decreased oxygen levels in blood) caused by respiratory disorders
such as COPD, pulmonary hypertension,
cor pulmonale, pneumonia, atelectasis (lung collapse),
lung cancer, and pulmonary emboli; cardiovascular disorders such as
myocardial
infarction, dysrhythmias, angina pectoris, and cardiogenic shock; central
nervous system disorders such as overdose of opioids, head injury, and sleep
apnea.
.....
-Oxygen toxicity- may result from prolonged exposure to a high level
of oxygen. High levels of oxygen.....can lead to acute respiratory
distress
syndrome....All
levels above 50% and used for longer than 24 hours should be considered
potentially toxic. Levels of 40% and below may be regarded as relatively
nontoxic and
may not result in development of significant oxygen toxicity if exposure
period
is short."
In other words, high levels of oxygen (100% via rebreather/non-rebreather
mask) is ideal for emergency situations, but not more than 24 hours!!
After stabilization
of initial symptoms, it is best to go to a lower oxygen percent, usually
2-3 LPM (for a delivery of 21 to 30 percent oxygen). Of course, these
guidelines are designed for medical professionals who can monitor the PaO2 and SpO2 so
unless you have a pulse
ox[imeter] at home, you're going to be going
with best guess. Watch for breathing difficulties such as trouble breathing,
rapid
breathing,
cough, restlessness.
So, in summary, high oxygen to deal with the immediate emergency, then
switch to low oxygen after stabilization or before 24 hours pass. I am
a recent
graduate, so anybody with more experience please feel free to jump in
with any corrections.
