Low CO2 what to do?

CritterLover, BSN, RN · Jul 18, 2008

It would depend on the patient.

Low co2 on a chemistry panel is a sign of metabolic acidosis (I'm assuming this is the chem panel and not the abg). It tends to correlate with the bicarb level on the abg.

Some chronic renal patients tend to have low co2 levels, and it is "normal" for them.

Otherwise, I'd be looking for other causes of metabolic acidosis -- sepsis and dka come to mind.

How are they breathing? Are they working hard? Are they acting like they are trying to blow off co2 in order to normalize their ph? Are they alert?

What was the co2 yesterday? If it was 10 yesterday, then the patient is getting better. If it was 22 yesterday, then I'd be concerned.

I'd also be interested in what the abg might show. If there was reason to call the doc, I'd probably ask if I could get an abg.

A co2 of 14 makes me want to watch the patient closer, and look for causes.

Acosmo27 · Jul 18, 2008

critterlover said:
It would depend on the patient.
Low co2 on a chemistry panel is a sign of metabolic acidosis (I'm assuming this is the chem panel and not the abg). It tends to correlate with the bicarb level on the abg.
Some chronic renal patients tend to have low co2 levels, and it is "normal" for them.
Otherwise, I'd be looking for other causes of metabolic acidosis -- sepsis and dka come to mind.
How are they breathing? Are they working hard? Are they acting like they are trying to blow off co2 in order to normalize their ph? Are they alert?
What was the co2 yesterday? If it was 10 yesterday, then the patient is getting better. If it was 22 yesterday, then I'd be concerned.
I'd also be interested in what the abg might show. If there was reason to call the doc, I'd probably ask if I could get an abg.
A co2 of 14 makes me want to watch the patient closer, and look for causes.

No, no, no. Co2 is considered an acid therefore low co2 would be considered alkalotic first off. Second, when there is a problem with co2 (versus hco3) it is considered a respiratory problem not a metabolic problem.

This would mean that, that a low co2 level (assuming that the hco3 level is normal)... Would be respiratory alkalosis.

Things that could cause this would be anything that causes hyperventilation... Pain, asa overdose, anxiety etc... Brown bag breathing can help increase co2 level..

ukstudent · Jul 18, 2008

Acosmo27 said:
No, no, no. Co2 is considered an acid therefore low co2 would be considered alkalotic first off. Second, when there is a problem with co2 (versus hco3) it is considered a respiratory problem not a metabolic problem.
This would mean that, that a low co2 level (assuming that the hco3 level is normal)... Would be respiratory alkalosis.
Things that could cause this would be anything that causes hyperventilation... Pain, asa overdose, anxiety etc... Brown bag breathing can help increase co2 level..

You are correct ONLY if the CO2 is from an abg. Critterlover is totally correct in the meaning of a CO2 in a chemistry panel.

CritterLover, BSN, RN · Jul 18, 2008

acosmo27 said:
No, no, no. Co2 is considered an acid therefore low co2 would be considered alkalotic first off. Second, when there is a problem with co2 (versus hco3) it is considered a respiratory problem not a metabolic problem.
This would mean that, that a low co2 level (assuming that the hco3 level is normal)... Would be respiratory alkalosis.
Things that could cause this would be anything that causes hyperventilation... Pain, asa overdose, anxiety etc... Brown bag breathing can help increase co2 level.

As I stated in my post, I'm talking about co2 in the chem panel, not the blood gas.

Co2 in the chem panel correlates with hco3 on the blood gas.

Low co2 in the chem panel is indicative of metabolic acidosis, though you really need to look at a blood gas to be sure.

The co2 level in the blood gas and chem panel are measured in different units, so don't expect them to correlate.

Acosmo27 · Jul 18, 2008

oops! My bad... thanks for clearing that up!

GilaRRT · Jul 18, 2008

A little off topic; however, I just wanted to emphasize that carbon dioxide is not an acid. Hydrogen ions are acid. PH is a logarithmic scale used to measure hydrogen ions. Now, when carbon dioxide enters the plasma, a significant amount of carbon dioxide is transported in the form of bicarbonate. During this process carbonic acid is produced. The hydrogen ion does not even come from carbon dioxide. The reverse occurs at the level of the alveoli.

barefootisbetter · Nov 18, 2011

I'm so curious. You all sound like you know what your talking about, so here is my situation. I have suffered from chronic back pain for about 5 years straight. The culprit could be a combination of things: lots of migrant labor and hard physical labor, such as raking blueberries, picking apples, cleaning homes on my own for 6 years, and stress from a divorce after 8 years of marriage. And I'm 27, with a 10 yr old son. You can imagine my stress level. I've been through very hard hitting relationship issues to top it off. So, all of this combined, the stress, then the pain becoming chronic, ordained me with anxiety, tension, sensitivity, and at times full blown panic attacks. I won't beat around the bush, it's been rough. And money's been tight. Which leads to my ultimate point.

I screened for a medical study to earn some extra bucks testing pain meds for a few weekends. They did all their usual tests, took blood, ECG ect, and they called me back the next day to tell me they need anther blood sample because my carbon dioxide levels were a little too low. I asked her what causes that, she didn't know, which leads to my research online.

Wow. This is a very serious issue. I've only been reading up on it for 30-40 min, and it's really hitting me hard how important this is. And I haven't even mentioned the most important part. Low levels of carbon dioxide can lead to muscle spasms, which is what the doctor determined is causing my roller coaster, sometimes completely debilitating back pain. I've had x-rays and an MRI, been to chiropractors, Neurologist, Acupuncturist, Yoga master.... they all seem to find the same conclusions. My muscles are spazzing out! Did all of this really start with the improper breathing stress can cause? It seems so. Did the stress I allowed myself to feel so intensely, really lead to such misery and hardship? Damn, I need to pay attention here. There are many things going on I am not aware of.

So, it seems before I do anything else...... I need to calm the **** down and breath properly!! Since I found out improper breathing causes all of this, I started paying attention to my breathing as it changed. I have terrible breathing habits. I breath shallow breaths, from my chest, and often breath fast, and shallow. The energy I noticed I lost was astonishing.

nurseprnRN, BSN, RN · Nov 19, 2011

Saying a low co2 on a chem lab "correlates with bicarb in a blood gas" is a little confusing to some. I hope this helps.

While it is true that hydrogen ions work as acids, for clinical purposes it is appropriate to think of co2 in abgs as an acid, balanced by the hco3 (the bicarb). When there is a metabolic acidosis (low serum bicarb) the way the body compensates for that is by hyperventilation to remove co2 (this is the low chemistry co2), so the overall body acid level is decreased.

A low chemistry co2 or low abg bicarb and low abg co2 would make me go see if the patient is hyperventilating to compensate for an acidosis, and then see what was causing that. Some choices are diabetic ketoacidosis, acetylsalicylic acid overdose, lactic acidosis (from anoxic tissues-- worst would be mesenteric artery thrombosis, look for huge belly pain), and sudden renal failure with failure to excrete h+.