8jimi8
CFRN
- 1,792
- 9
- 38
JP just quit, he's trying to prevent shock...
Metal, just stop. if you can, delete your posts and we will take the shovel away. Or as Meclin says.... " Dig up..."
NREMT few questions
- Thread starter thenuke1
- Start date
JP just quit, he's trying to prevent shock...
Metal, just stop. if you can, delete your posts and we will take the shovel away. Or as Meclin says.... " Dig up..."
JPINFV
Gadfly
- 12,681
- 197
- 63
Blood loss being fast or slow is irrelevant since hemoglobin, which is confined to the red blood cells, is, for all practical intents, the only way oxygen is moved around the blood. Increaing the fraction of inhaled oxygen does nothing to increase the amount of hemoglobin or slow down its loss.
I think the best illustration for this is the oxygen content equation.
CaO2 = (SaO2 x Hb x 1.34) + .003(PaO2)
The first part is the amount of oxygen carried on hemoglobin. The second part is the amount that is dissolved in. Consider additionally that the normal amount of hemoglobin is 14 g/dL and normal SaO2 is around 97%. PaO2 with 100% inspired oxygen (which doesn't happen prehospitally anyways) is 760 mm/Hg. With room air, it's .21*760, which is 159.6
So, 0.97*15*1.34=19.497=amount of oxygen bound by hemoglobin.
With room air, the amount of oxygen dissolved in plasma is 0.479
Under 100% inhaled oxygen, the oxygen dissolved in plasma is 2.28. Mind you, you aren't going to get an airtight seal with a NRB anyways, so you are going to have a mix of atmospheric air and medical oxygen which is going to decrease PaO2.
A few other things to think about. The concentration of hemoglobin isn't going to decrease in the short term unless you start administering a lot of IV fluids. So, as RBCs leave circulation, they do so in plasma. So even under the best of conditions with the NRB mask you're still going to get about 10:1 ratio of oxygen bound to hemoglobin to oxygen dissolved in plasma. I'm not sure how much oxygen can dissolve in saline, but saline does not carry RBCs, so the major part of the carrying capacity doesn't come back with saline.
FiO2 and PaO2 is not the same. As the air moving through the conducting airways picks up water from the walls of the airway, the concentration of oxygen (as well as other gases) decreases.
V/Q mismatches can be present, which can further decrease the ability of oxygen to move into the blood stream.
As far as "something being better than nothing" err... no. I would not subscribe that just because you can do something doesn't mean you should.
Of course, one final thing to think about. This is stopping hypoxia, not hypoprofusion.
I think the best illustration for this is the oxygen content equation.
CaO2 = (SaO2 x Hb x 1.34) + .003(PaO2)
The first part is the amount of oxygen carried on hemoglobin. The second part is the amount that is dissolved in. Consider additionally that the normal amount of hemoglobin is 14 g/dL and normal SaO2 is around 97%. PaO2 with 100% inspired oxygen (which doesn't happen prehospitally anyways) is 760 mm/Hg. With room air, it's .21*760, which is 159.6
So, 0.97*15*1.34=19.497=amount of oxygen bound by hemoglobin.
With room air, the amount of oxygen dissolved in plasma is 0.479
Under 100% inhaled oxygen, the oxygen dissolved in plasma is 2.28. Mind you, you aren't going to get an airtight seal with a NRB anyways, so you are going to have a mix of atmospheric air and medical oxygen which is going to decrease PaO2.
A few other things to think about. The concentration of hemoglobin isn't going to decrease in the short term unless you start administering a lot of IV fluids. So, as RBCs leave circulation, they do so in plasma. So even under the best of conditions with the NRB mask you're still going to get about 10:1 ratio of oxygen bound to hemoglobin to oxygen dissolved in plasma. I'm not sure how much oxygen can dissolve in saline, but saline does not carry RBCs, so the major part of the carrying capacity doesn't come back with saline.
FiO2 and PaO2 is not the same. As the air moving through the conducting airways picks up water from the walls of the airway, the concentration of oxygen (as well as other gases) decreases.
V/Q mismatches can be present, which can further decrease the ability of oxygen to move into the blood stream.
As far as "something being better than nothing" err... no. I would not subscribe that just because you can do something doesn't mean you should.
Of course, one final thing to think about. This is stopping hypoxia, not hypoprofusion.
cmetalbend
Forum Crew Member
- 76
- 1
- 0
Well I have no doubt I can use the material in the last post, more than a video from you-tube. Although it is a damn funny Movie. Thanks for the discussion and debate. But it's really sad we couldn't answer the first Post request as to why we still apply o2 to a non-hypoxic patient. Or atleast why the material for EMT-B's states we should. :wacko:
8jimi8
CFRN
- 1,792
- 9
- 38
A better question is why we let basics administer ANY medication at all.
You apply o2 to every patient because of a lack of education.
Not every patient needs it. Not every patient needs it. Not every patient needs it.
Just remember that. Use your assessment skills to know when a patient needs oxygen and you if can't tell when they do, then you have no business using it.
cmetalbend
Forum Crew Member
- 76
- 1
- 0
Just another personal stab toward EMT-B's(not to worry, he prides himself)
Quite possibly true, but in regards to NREMT and state practicals, if you forget the o2 at the basic level, you failed.
Agreed
For sure, and above all in the real world.
8jimi8
CFRN
- 1,792
- 9
- 38
To quote myself
Don't worry you will feel the jab when I give it.
(jab incoming)
You being the prime example of why Basics should NOT be allowed to administer medications. Without referencing JP's post, can you please explain what shock is and why oxygen is the intervention that you believe will treat it?
I suggest you pull out your emt basic text and look up shock. Then i suggest you read the chapter that introduces oxygen as a drug. Then i challenge you to synthesize and apply that material to this thread and see if you come up with any mistakes or mistaken assumptions you might have been employing when you were posting previously.
Myself said:
Don't worry you will feel the jab when I give it.
(jab incoming)
You being the prime example of why Basics should NOT be allowed to administer medications. Without referencing JP's post, can you please explain what shock is and why oxygen is the intervention that you believe will treat it?
I suggest you pull out your emt basic text and look up shock. Then i suggest you read the chapter that introduces oxygen as a drug. Then i challenge you to synthesize and apply that material to this thread and see if you come up with any mistakes or mistaken assumptions you might have been employing when you were posting previously.
cmetalbend
Forum Crew Member
- 76
- 1
- 0
OK I accept. Lets start at the top. Perfusion is the supply of oxygen to, and removal of waste from the cells and tissues of the body. Hypoperfusion(shock) is the lack of the bodys ability to circulate the blood carrying the Oxygen to, and waste from the tissues & Cells. An EMT's interventions are limited to A)Maintain an open airway AND admin high consintrations of o2. B) elevate the lower extremities, if there is no major trauma(spine,head and such). C) cover the patient with a blanket. D) transport. Since shock is the failure of the cardiovascular system to provide sufficient blood to all the vital tissues. Administration of Oxygen helps the blood that does reach the tissues deliver the maximum amount of Oxygen. OK do you agree with this so far?
8jimi8
CFRN
- 1,792
- 9
- 38
While I agree that in the face of hypoperfusion getting as much O2 to the tissues as possible is beneficial....
Your definition of perfusion is incomplete.
How does oxygen help circulation?
This would be the reason i'm jabbing at you.
Shock will not be prevented, nor cured by administration of oxygen.
JPINFV
Gadfly
- 12,681
- 197
- 63
Not quite. Profusion is the supply of blood to the tissues. One of the components of blood is oxygen, however if the oxygen content of blood is low, than it is hypoxia (or, if PO2 is low, "hypoxemia"). So a patient can have good profusion, but low oxygen. Remember, oxygen isn't the only thing in the blood that cells use.
Yes, the basic interventions that EMTs are limited to is basic airway maneuvers, supplemental oxygen, shock position (which is another thread completely), protection against loss of heat, and transport.
Yes, shock is the failure of the cardiovascular system to provide sufficient blood.
What I disagree with, though, is that in a patient that is adequately oxygenating the blood that supplemental oxygen is useful to prevent hypoprofusion. There's a finite amount of oxygen that can be loaded onto the blood and the vast majority of that is bound to hemoglobin. In a patient with hypovolemic shock due to trauma, the important thing is to stop bleeding and increase fluids (with packed red blood cells as needed), largely to do it in that order. This is why a certain amount of hypotension is permitted in patients with traumatic injuries.
8jimi8
CFRN
- 1,792
- 9
- 38
AND no one would have a problem with your posts if you stuck with " i don't know." Rather than confusing someone else who was smart enough to ask a question, when they didn't.
cmetalbend
Forum Crew Member
- 76
- 1
- 0
Seriously, relax. I said SO FAR. Too much info at once gives too much to argue about.
cmetalbend
Forum Crew Member
- 76
- 1
- 0
I repeated it nearly word for word as printed, after I read the chapter.
Don't know, wasn't covered in that depth.
I'll finish my rational later today, fire meeting to attend.
Scooter76
Forum Probie
- 18
- 0
- 0
Hey all.. took my Paramedic exam..
came across this type question..
I finished with this question... I will summerize.
I had this situation where I determined it was SVT. I elminated two answers, the question asked what would I administer first?
choices left were 1.) give 6 mg adenosine IV push. 2.) give a cartiod massage.
I was thinking of #2 cuz of vagal manuvers first.. am i wrong?
came across this type question..
I finished with this question... I will summerize.
I had this situation where I determined it was SVT. I elminated two answers, the question asked what would I administer first?
choices left were 1.) give 6 mg adenosine IV push. 2.) give a cartiod massage.
I was thinking of #2 cuz of vagal manuvers first.. am i wrong?
8jimi8
CFRN
- 1,792
- 9
- 38
Do not repost NREMT questions. You signed an agreement not to discuss the contents of the test. Personally it doesnt bother me, but it is against the posting policy on this forum.
Only doctors may perform carotid sinus massage.
reaper
Working Bum
- 2,817
- 75
- 48
Where do you get that last part from?
Scooter76
Forum Probie
- 18
- 0
- 0
I thought it was you couldnt post exact questions from the exam. I didnt.
I was very vague about the question. Didnt state the question at all.
I was very vague about the question. Didnt state the question at all.
8jimi8
CFRN
- 1,792
- 9
- 38
It has been re and over emphasized in my last two ACLS courses. Vagal maneuvers ok, carotid sinus massage for physicians only.
Maybe they trained you too long ago my friend
reaper
Working Bum
- 2,817
- 75
- 48
I teach ACLS. No where has it ever been said that it is by physician only.
Every service I have been with over the last 20+ years have had it in their scope. Maybe it is just a TN thing.
Every service I have been with over the last 20+ years have had it in their scope. Maybe it is just a TN thing.
8jimi8
CFRN
- 1,792
- 9
- 38
Let me see if i can actually find the little sentence that I can see in my mind's eye. Obviously being an instructor has more credibility than me taking the class twice. But i could swear that was drilled into my head.
reaper
Working Bum
- 2,817
- 75
- 48
Here is a link to the AHA journal.
Scroll down to the VVM section. It still list CSM, with no mention of physician only.
http://circ.ahajournals.org/cgi/content/full/112/24_suppl/IV-67
Scroll down to the VVM section. It still list CSM, with no mention of physician only.
http://circ.ahajournals.org/cgi/content/full/112/24_suppl/IV-67