ABG tests

[peachy297]

Last week I was hospitalized because of low oxygen levels.  My PO2 upon admission was 40.  My PC02 was slightly elevated and I really don't have the rest of the results.  I do have the results from the test administered prior to my dismissal from the hospital which had improved.  My questions...prior to going to hospital my SAo2 at rest was between upper seventies and low eighties (normal for me is between 90 and 96).   When is the right time to seek medical help on SAo2 levels?  They put me on prednisone and I am now weaning off and it seems as if my oxygen levels are dropping again.  Any idea what might be going on?  Something new on echocardigram showing pulmonaary hypertension.  I have had several posts here for your referral.  Thanks for all you do.  I have no health insurance and to be honest...I'm not real sure about the doctors I've seen.  Thank you so much!

[National Jewish Health]

The information you have provided suggests that you know the difference between p02 (a pressure)  and oxygen saturation (a measure of how closely the oxygen attached to the red blood cells approaches the maximum that can be attached (100%).  Each is a way of reporting oxygen level in the blood.  The normal values at sea level are roughly a p02 of 85-100 mm of mercury and the saturation 94-96%.  The right time to seek help, given your normal saturations of 90-96 would be a saturation of 85% or less, when accompanied by respiratory distress and/or a saturation of less than 75-80%, even without respiratory distress.  

It appears that you have COPD and that the recent fall in oxygen levels was secondary to a severe exacerbation, what with your p02 having fallen to 40 at the time of admission.  This is a very low, a very dangerous level of p02 and you should never wait that long again before going to the hospital.

Pulmonary hypertension is commonly associated with COPD and the level of hypertension can rise precipitously in the presence of a fall of one’s oxygen saturation and lead to (right) heart failure.  I suspect that that is what is happening now, coincident with reduction of the prednisone.  The oxygen levels you list below suggest that, even when things seem stable, your oxygen levels may be borderline (maybe a lot worse during sleep)  and it may not take much respiratory failure to cause a rapid decline in the oxygen level.  

You must request reevaluation now.  The evaluation should lead to treatment until your lung condition is deemed to be stable and, at that time, you should have your oxygen levels checked while awake, while asleep and with exertion.  You may need to be using supplemental oxygen if your condition is to remain clinically stable.

Good luck