Hypoxia and Medicine

What is a dangerous carbon dioxide level in your body? Like with say, hypoxia and dyspnea.?

Public Comments

1. When carbon dioxide reaches certain concentration in the pulmonary alveoli (hypercapnia) and in the circulatory stream, such as a mix of seven volumes (70%) of oxygen and three (30%) of carbon dioxide, it will diminish the efficiency of the functioning of the brain. It is known that carbon dioxide (CO2), when inhaled pure (100%), causes the death of the human body due to asphyxia or suffocation. In other words, the concentration doesn't have to be very high in the beginning when the brain stops functioning. Once this happens the person will not be aware of their surroundings and the inhalation of more carbon dioxide.
2. You can have a blood test called an Arterial Blood Gas which is drawn out of an artery. A normal CO2 level is between 35 - 45mmHg. A dangerous level is over 60mmHg and above.
3. normal arterial pco2 =40mm hg. 3%increase dobles the ventilation in normal conditions.
4. Depends on what you mean by dangerous. Mild hypercarbia has actually been found to be fairly benign. Once you get to a pCO2 of about 80 or so, then you start to develop CO2 narcosis. This can be a problem in that the CO2, which normally causes you to breathe harder and get rid of the CO2, may actually depress your breathing at that level and thus you go into a dangerous spiral. If you're being ventilated mechanically, then perhaps not as much. Roughly the pH goes down by about 0.08 for each 10 the CO2 goes up (acutely). So, if this happened all at once, then your pH would drop from about 7.44 to 7.16. This is fairly acidotic, and not very good for you. Eventually, your body starts to compensate for that =, and your pH will rise. In that case, the 80 is not as bad. Acute v. chronic changes are also important. If you have COPD and are chronically at a pCO2 of 60, that's not great but I can live with it. If you are normally at 40 and go to 60, then I might intervene a little quicker. Finally, if you have raised intracranial pressure, then even normal CO2 can be bad, since the more CO2 you have, the greater your cerebral blood flow and thus the greater your intracranial pressure. Short answer-- it depends ;). I'd say a pCO2 in the 50s would make me start thinking, although I wouldn't necessarily act, depending on the situation. A pCO2 of 60 or up, would probably make me try to get it down if possible.
5. agree with the answer above. under effect of narcotics for instance, i've seen a PaCO2 of 70 in patients without any sequelae. however, once you get into the 80's, you need to worry about CO2 narcosis- that's what will ultimately be fatal. the acidosis one develops from hypercarbia won't kill you.