Understanding Oxyhemoglobin dissociation curve

Daytonite, BSN, RN · Jun 4, 2005

The oxyhemoglobin disociation curve is basically the line that is formed when you plot out on a graph the Sa02 (hemoglobin saturation with oxygen or O2 sat) and the hemoglobin desaturation. Hemoglobin saturation is measured as a percentage. Hemoglobin desaturation is measured in mmHg. It is in the shape of an "S".

The curve shifts to the right with acidosis and elevated levels of carbon dioxide (hypercapnia). This means that the hemoglobin molecules have difficulty maintaining their bond with oxygen cells so the oxygen molecules can move easily into the cells.

The curve shifts to the left in alkalosis. This means that the hemoglobin molecules want to hang on to their oxygen molecules and there is a build up of carbon dioxide in the cells.

Does this help?

VickyRN, MSN, DNP, RN · Jun 4, 2005

The oxyhemoglobin disociation curve is basically the line that is formed when you plot out on a graph the Sa02 (hemoglobin saturation with oxygen or O2 sat) and the hemoglobin desaturation. Hemoglobin saturation is measured as a percentage. Hemoglobin desaturation is measured in mmHg. It is in the shape of an "S".
The curve shifts to the right with acidosis and elevated levels of carbon dioxide (hypercapnia). This means that the hemoglobin molecules have difficulty maintaining their bond with oxygen cells so the oxygen molecules can move easily into the cells.
The curve shifts to the left in alkalosis. This means that the hemoglobin molecules want to hang on to their oxygen molecules and there is a build up of carbon dioxide in the cells.
Does this help?

Daytonite, you are an incredible resource. Thank you so much for your help in this Forum. If you haven't already done this, you ought to consider going into Nursing Education.

Here's a little more information on the Oxyhemoglobin Dissociation Curve (has a nice graph):

http://www.rnceus.com/abgs/abgcurve.html

AussieKylie · Jun 6, 2005

Thanks for both your help Daytonite & VickyRN. I will try my best to understand it by reading over and over. Appreciate the effort of your help

:)

AussieKylie · Jun 6, 2005

To VickyRN, that weblink too was mighty helpful. Appreciate you sharing the web link. THANK YOU :)

surreal · Jun 19, 2005

oh no my instructor just went over this the other day and i can barely remember a thing! hahah

he talked about how from 90-100% the curve doesn't decrease (its flat), but as soon as you start getting down past 90% it rapidly decreases... and is why sao2 from 90-100 is WNL but as soon as you begin to drop down under 90 it gets more serious.... for example a drop from 95 to 92 wouldnt be nearly as dramatic as a drop from 90 to 87. the differences are the same and they are small but once under 90% those small differences in sao2 reflect large changes in the pao2.

geesh i need to review this one too!! hahahah.. good luck!

Hi again
I am doing review for my upcoming exams at Uni. I love to get good marks and hope to achieve that.
I am having problems understanding 'Oxyhemoglobin dissociation curve'. I know there is information on the Critcare Education website however I was hoping someone could just explain it nicely and clearly without me saying Well what does it mean? All big words can bamboozle me. So if someone can explain the concept easily then maybe I can go over it and it might make more sense :uhoh21: Well I hope so :)
Thank You