Final answer:
Supplemental oxygen can increase CO2 retention, known as hypercapnia, by displacing CO2 from hemoglobin and by suppressing the hypoxic drive in certain patients with lung disease. Situations like pneumonia, heart failure, or depressant drugs can impair respiratory function and lead to hypercapnia. Conversely, hyperventilation causes hypocapnia, which is lower CO2 levels in the blood.
Step-by-step explanation:
Oxygen-induced Hypercapnia
Supplemental oxygen administration can lead to increased CO2 retention, which is the presence of elevated levels of carbon dioxide in the blood, also known as hypercapnia. This paradoxical increase in CO2 can occur due to a couple of reasons. One reason is the Haldane effect, where oxygenation of blood in the lungs displaces carbon dioxide from hemoglobin which increases the amount of free CO2 in the blood. Another reason is that in patients with chronic obstructive pulmonary disease (COPD), high levels of oxygen can suppress their hypoxic drive. This is a condition where the body's normal response to low blood oxygen levels is diminished, leading to hypoventilation (reduced breathing).
Hypercapnia itself can cause confusion, depressed consciousness, and in severe cases, coma. The condition occurs when anything impairs respiratory function, leading to hypoventilation. Situations that can cause this include diseases such as pneumonia and congestive heart failure. Certain drugs that depress the respiratory system, such as morphine, barbiturates, or ethanol can also lead to hypoventilation and subsequent hypercapnia.
Contrastingly, hypocapnia is a condition of abnormally low levels of CO2 in the blood and occurs with over-breathing (hyperventilation), which expels CO2 from the body at a faster rate. It can be caused by conditions such as salicylate toxicity, elevated room temperatures, fever, or hysteria.