What does "hypercapnia" refer to?

Hypercapnia specifically refers to elevated levels of carbon dioxide (CO2) in the blood. This condition is typically a result of inadequate ventilation, where the body is unable to expel CO2 effectively. Increased carbon dioxide levels can lead to respiratory acidosis, which may manifest as symptoms such as headaches, confusion, and drowsiness. Understanding hypercapnia is crucial in the field of oxygen therapy, as it can affect a patient's respiratory status and overall health, prompting the need for appropriate interventions to restore normal gas exchange and improve ventilation.

The other options describe different conditions related to respiratory and cardiovascular health but do not accurately define hypercapnia. Low levels of oxygen in the blood is referred to as hypoxemia, low blood pressure is termed hypotension, and decreased lung capacity relates to various pulmonary conditions but does not specifically equate to elevated carbon dioxide levels.