O2 Sat is 100% but the hemoglobin is 5g/100ml.. what is wrong with the patient?

a patient has O2 sat= 100% and we dont think they're hypoxic.. but then the tissues have 5g/100ml=tissue hypoxia.. so what? why is this important?'

my professor gave us an example btw three patients. all the pts have O2 sat of 100%.. the only difference is the Hgb.
pt 1 has Hgb of 5g/100ml
pt2 2 Hgb of 10g/100ml.
pt 3 has 15g/100ml she wanted to show how a patient with Hgb of 15 has more blood cells to be saturated with O2. a patient may have O2 sat=100%, but the patient w/ 5g/100ml does not have enough blood cells compared with the pt with 15g/100ml. so there's just a lot of oxygen in the body that is not being carried by red blood cells.
what happens to that excess oxygen not being picked up by RBCs? what will the patient look like if have only 5g/100ml of Hgb? they will be cyanotic?

what is the priority intervention for a person with cyanosis?

how would you put this in a scenario?

Prolonged tissue hypoxia results in increased levels of lactic acid which can lead to cell death. Increased cell death leads to all sorts of bad things.

The patient is hypoxic. Just not 'generally hypoxic.'

More data needed.

edit: comment made prior to OP updating/editing his/her post.

I guess I don't understand the 5g/100ml. Does that mean the Hgb is 5? Or what exactly is that measuring? What other tests/diagnostics are we looking at here? (ABGs, CBC, any invasive monitoring?)

*Just a comment here: I notice the OP is a nursing student. I just wanted to say that people here are more than willing to assist in answering your questions if it helps you to develop critical thinking skills. Think of nursing problems as not necessarily have just one right or wrong answer as there are many pieces of the puzzle that nurses must use to problem solve and figure out what is wrong with the patient. It actually helps you if we ask you additional questions to make you think, rather than just answering the question for you. Also, you may have some luck posting in the student forums.*

"what happens to that excess oxygen not being picked up by RBCs? what will the patient look like if have only 5g/100ml of Hgb? they will be cyanotic?

what is the priority intervention for a person with cyanosis?

how would you put this in a scenario?"



I'm a little concerned that we are actually doing your homework for you. These questions appear to be from an assignment. I checked out some of your threads and it appears that you are struggling academically. Having us answer your homework questions is not the way to pass your classes. While all of us here want to see our student members do well we also want you to achieve the critical thinking skills that will be necessary for you to be successful as a nurse. Can you join a study group of students in your class? That would be the best place for you to work out the answers for the many questions you have posed in several posts. I'm not trying to be mean or to discourage you from seeking help from experienced nurses but the only way you are going to grasp the concepts being taught is by not having them spoon-fed to you. You might also consider getting a tutor to help you or perhaps someone who can give you some tips for more productive study habits.
Good luck with your schooling.

I hope I am understanding your question correctly. I understand when you are in nursing school, it is sometimes difficult to sort through all of the information and to assimilate it into something useful for you to use. Hope this helps...
A patint with a Hgb of 5 may or may not be cyanotic, even with a sat of 100%. They will most certainly be very pale, even sallow. They may or may not be short of breath (more than likely so). They may have an altered mental status. Priority intervention for an individual with cyanosis typically depends on the cause, it is not one size fits all. that is where your ABCs come into play. A breakdown of any one of those could cause cyanosis. I am unsure as to how to address the "oxygen in the body that is not being carried by the RBCs". Oxygen is exchanged at the alveolar level in the lungs- if there is no hgb to pick it up, it does enter the bloodstream as far as I understand.
A primary concern with profound anemia such as that is tissue perfusion. THe blood may be going where it needs to, there is just not enough O2 in it to provide adequate tissue perfusion. It is possible to suffer an MI from anemia due to lack of perfusion to the myocardium.
I hope this helps. I know when I was in nursing school I had a hard time actually picturing in my head what the patient would look like and had several whys?? and hows??? As a previous poster suggested, a study group may be of benefit to you. Best wishes to you.

Please study up on the oxygen-hemoglobin dissociation curve.

Then come back and post your thoughts.

This is an interesting, and sometimes poorly-understood concept that is very important to our patients' well-being and our management of them.

I have lived this, my hgb was 6.3, 02 on RA was 96% and 100% 2/L. I was very short of breath because of course there is not enough RBC's to carry the O2. So of course I was extremely SOB and had a hard time convincing a new nurse that I needed O2. She kept telling me, your 02 sat is 96% you do not need 02. Well yeah I did. I am not receiving enough O2 because my Hgb is 6.3, so I explained if there are not enough RBC's to carry the O2, I need the O2. Sats are going to be normal, they do not measure the RBC's. Understand?? Maybe that is not what you are looking for?

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Originally Posted by mashamontago

a patient has O2 sat= 100% and we dont think they're hypoxic.. but then the tissues have 5g/100ml=tissue hypoxia.. so what? why is this important?'

my professor gave us an example btw three patients. all the pts have O2 sat of 100%.. the only difference is the Hgb.
pt 1 has Hgb of 5g/100ml
pt2 2 Hgb of 10g/100ml.
pt 3 has 15g/100ml she wanted to show how a patient with Hgb of 15 has more blood cells to be saturated with O2. a patient may have O2 sat=100%, but the patient w/ 5g/100ml does not have enough blood cells compared with the pt with 15g/100ml. so there's just a lot of oxygen in the body that is not being carried by red blood cells.
what happens to that excess oxygen not being picked up by RBCs? what will the patient look like if have only 5g/100ml of Hgb? they will be cyanotic?

what is the priority intervention for a person with cyanosis?

how would you put this in a scenario?

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Normally I would be in the not doing the homework group but I think this is a case of poor teaching as opposed to critical thinking.

Think about it in terms of oxygen movement. The pump (the heart), the tubes (the blood vessels) and the blood). To get adequate perfusion you have to have all three. In your case the professor is correct. The term you are looking for is oxygen carrying capacity. If you have less blood cells you cannot carry as much oxygen.

Here is a very nice (but long) article from the British Medical Journal):
http://www.pubmedcentral.nih.gov/art...?artid=1114207

Down in the middle you have this

"Mechanisms causing failure of global oxygen transport

• Reduction in cardiac output (for example, heart failure) results in “low flow” tissue hypoxia
• Fall in haemoglobin concentration or failure of haemoglobin mediated oxygen binding or release (for example, haemoglobinopathy) produces “anaemic” tissue hypoxia
• Failure of oxygen uptake by blood (for example, inadequate ventilation, ventilation-perfusion mismatching, low Fio2) results in “hypoxic” tissue hypoxia"

So think about this in terms of your patient. You don't know what the cardiac output is but presumably its OK. You know the blood is low but there is good uptake (100% sat).

Now putting it all together. With 100% sats you are adding oxygen. So lets say that you are breathing in 100% oxygen. It enters the lungs but only a small part can be taken up by the hemoglobin (even in normal patients). The oxygen hemoglobin disassociation curve is part of the answer but not the whole thing:
http://en.wikipedia.org/wiki/Oxygen-...ociation_curve

As you increase the amount of oxygen more oxygen is bound to the hemoglobin but its a small percentage. In your case you have already bound all or most of the hemoglobin with oxygen. The excess oxygen that you give is simply expired (it has nothing to bind to). So giving someone with a low hemoglobin will help bind an extra 2-4% but you are not addressing the primary problem.

If you have a hemoglobin of 10 with 100% sat you are carrying twice as much oxygen as if you have a hemoglobin of 5. Hgb of 15 is three times more (its actually more complicated than this but for these purposes it suffices).

So to answer your first question the oxygen is simply expired. Now the question of cyanosis. May people confuse cyanosis and hypoxia. Hypoxia is the lack of oxygen to the tissues. The patient with a hemoglobin of 5 may or may not be hypoxic. Cyanosis on the other hand is caused by deoxygenated blood circulating in the capillaries. In general you need 5g/dl of deoxygenated blood to cause this. So since your patient has 100% saturations they will not be cyanotic. Cyanosis is usually seen in patient with either chronic (ie COPD) conditions or acute conditions such as choking.

Now this is where I have a problem. Either your instructor is fiendishly clever and set this question up to make you differentiate between hypoxia and cyanosis (in which case I owe them an apology for doing your homework for you) or is using the terms interchangeably and incorrectly. The second question makes me suspect the latter. The primary problem is cyanosis is that the RBCs are not getting enough oxygen. So the general solution is to deliver more oxygen. In a choking victim clearing the airway would be an intervention. In a COPD patient increasing the oxygen through oxygen supplimentation or increasing capillary delivery through a breathing treatment. In the case described above the patient is not cyanotic but may be hypoxic depending on their overall health. Since this is a defect in oxygen carrying capacity (not enough blood). The intervention is more blood.

As far as the third (for cyanosis). You are at the playground and you hear a young boy near you gasp. He puts his hands to his throat. He is unable to speak and you notice his lips turning blue. What is your intervention.

Or (for hypoxia) You are taking care of a 88 yo female who is dizzy, pale and diaphoretic. Her oxygen saturation is 100% on 2L NC. What other information do you need to assess her oxygenation status.


Good luck

David Carpenter, PA-C

Having enough tissue perfusion has a couple of parts:
1. Is there enough oxygen?
2. Is it getting to the tissues?

There are a few reasons why #2 can not happen. It may be that the patient has bled, or has anemia (low Hb) for another reason, or just doesn't have enough blood volume getting around for some reason. The end result is that even if you're giving oxygen, there's no Hb for it to bind to, so it can't get to the tissues.

It's a little misleading, because even though initially the O2 sat may be 100%, it's only measuring how WELL the oxygen is binding to the Hb that is there, not how MUCH is being bound.


What your teacher is trying to show you is that even if you're getting adequate oxygen, you're going to be hypoxic if there's a reason you can't USE the oxygen.

The O2-Hb dissociation curve shows you which conditions (acidosis, alkalosis, fever etc) cause Hb to drop O2 or bind O2.