It depends upon the cause of hypoxia. Be careful first not to confuse ischemia, which is a decrease in blood flow and thus supply of metabolic substrate and has a faster cellular degradation effect than hypoxia which is an oxygen deficit per se. Causes commonly are anemia or CO poisoning. In the former there is insufficient hemoglobin capacity and thus no gas replacement. In the latter, CO occupies the receptor to produce a stable monoxyhemoglobin. Thus there is not necessarily a gas dominant shift so much as a blood gas reduction in many cases.

mainly co2

Nitric Oxide also contributes in the problem

It depends upon the cause of hypoxia. Be careful first not to confuse ischemia, which is a decrease in blood flow and thus supply of metabolic substrate and has a faster cellular degradation effect than hypoxia which is an oxygen deficit per se. Causes commonly are anemia or CO poisoning. In the former there is insufficient hemoglobin capacity and thus no gas replacement. In the latter, CO occupies the receptor to produce a stable monoxyhemoglobin. Thus there is not necessarily a gas dominant shift so much as a blood gas reduction in many cases.

Hypoxia = low oxygen

Hypercapnia = high CO2.

You can get hypercapnia during hypoxia but not necessarily, especially if you are controlling it in the lab. If CO2 replaced the low oxygen then you are dead b/c that would be too much CO2. If done well, only nitrogen replaces oxygen.

Indeed, depends on a cause of hypoxia. If it is just low atmospheric pressure then ratio between gas concentrations remains the same, just absolute values of them is decreased proportionally. If oxygen is replaced with some gas - then that gas. local ischemia then with CO2. Same in case of asphyxia: CO2 is produced but not evacuated.

Sir

In case of normal hypoxia it is nitrogen which plays great role,but experimental hypoxia is made normally with cripton Or xenon gas for short period. Nitrogen washout is also popular technique for various lungs ailments dignosis. PCG,CLI

very interesting and critical discussion. I think in case of hypoxia no gas should replace oxygen except in condition where that particlar gas is for the replacement or is the cause of hypoxia,becausese each gas has its own function like NO and CO2 are vasodilators and decrease in O2 tension causes vasoconstriction in case of pulmonary circulation and vasodilation in case of systemic circulation. there is one possibility, if there is increased production of CO2 as a result of pulmonary vasoconstriction which causes an increase in the work load of respiratory muscle and so increase production of CO2. On the otherhand there will be an increased production of NO to fluid shear stress as result sytemic vasodilation: so we can say this is a replacement for decrease oxygen in case of hypoxia.

yes, of cource, if CO poisoning is the causehe of hypoxia, then CO is replacement for O2. this is an explanation for,: hope for the best Answer.

CO2 no doubt

it will be CO2. But sometime it may be Nitric Oxide. Rather correlate with cause of hypoxia.

Diagnostic errors may arise because some of the above manifestations are common to nitrogen nar­cosis, 02 toxicity and CO, retention. The attending physician should also consider cerebral arterial gas embolism and decompression sickness (DCS), should the above features develop during or after ascent by a diver breathing compressed gases.

There is clearly a great overlap in the different mechanisms by which the various diseases produce hypoxaemia.

Oxygen is not necessarily replaced. The organism can undergo anaerobic respiration which produces an acid by-product which decreases affinity of hemoglobin to oxygen. However, in a decrease in oxygen levels, the affinity of hemoglobin to O2 can get lower as well. Please try to research for associationsbetween levels of partial pressure in blood oxygen and hemoglobin saturation. Also, if CO is present in the bloodstream, most likely, carbon monoxide poisoning can happen because it binds greater than oxygen.

Sounds like the discussion is about hypoxemia (low arterial oxygen) and not hypoxia where tissues are deprived of oxygen. Hypoxemia is a cause of hypoxia. The most common cause of hypoxia is from high altitudes or anemia such the tissues are deprived of oxygen. So is the question about hypoxia or hypoxemia and related to blood or tissues?

In some cases, hydrogen sulfide.

Oxygen is usually a vasoconstrictor in systemic circulation and carbon dioxide a vasodilator especially in cerebral circulation. In the pulmonary circulation you have the opposite well at least oxygen is a potent vasodilator-carbon dioxide has varied effects dependent on species in pulmonary circuit. The bronchial smooth muscle responds to the changes in gases such ventilation matches perfusion. As mentioned before it depends on how hypoxia is induced -suffocation, high altitude, anemia, carbon monoxide poisoning, nitrogen or argon poisoning, and do you have normal function of lungs, heart and kidneys. The body responds to these conditions differently. If you were in a sealed bottle you would consume oxygen and produce carbon dioxide (cellular respiration). The carbon dioxide will form carbonic acid with the aid of carbonic anhydrase which dissociates into protons and bicarbonate (the main carrier of carbon dioxide in the blood as hemoglobin carries a small amount -10% ) . This will do two things first deoxygenated blood has a higher affinity for carbon dioxide (Haldane effect) and the lowering pH will increase unloading any oxygen from hemoglobin (Bohr effect). Normally carbon dioxide is carried in blood as bicarbonate. RBC have carbonic anhydrase which promotes a reversible reaction forming protons and bicarbonate in the tissues or it can go the other direction and form carbon dioxide as in lungs. Protons can't pass through cell membrane and chloride is exchanged (chlorine shift) with bicarbonate in the RBC (just like in the stomach when parietal cells make hydrochloric acid they use the chloride shift for a chlorine source and the bicarbonate alkalizes the blood (the alkaline tide that makes you sleepy). Without oxygen your brain ceases to function rapidly. Hemoglobin carries NO likely as a vasodilator to assist in perfusion, but I don't think it alters hemoglobin affinity of oxygen or carbon dioxide.

In hypoxia the tissues are deprived of oxygen, during hypoxia Co2 levels may be increased while the oxygen level decreased

Indeed, depends on a cause of hypoxia .

The very word "hypoxia" means low oxygen in the mixture of air.hus incase of hypoxia partial pressure of oxygen is fall as result tissues are not able to extract adequate amount of oxygen . It is an emergency we have to change hypoxia to normal air failing artificial respiration failing supply medical oxygen immediately. Mind hypoxia is not normal condition in atmosphere. regards