What condition is characterized by high levels of carbon dioxide in the blood?

The correct answer is characterized by an accumulation of carbon dioxide (CO2) in the bloodstream, a condition known as hypercapnia. This occurs when there is an imbalance in the respiratory system, which may happen due to inadequate ventilation or impaired gas exchange in the lungs. When CO2 levels rise, it can lead to various physiological effects such as respiratory acidosis, confusion, fatigue, and can ultimately affect overall body function.

Hypoxia refers to a deficiency in the amount of oxygen reaching the tissues, which is fundamentally different from the excess of carbon dioxide seen in hypercapnia. Asphyxia is a state where there is insufficient oxygen and excess carbon dioxide, but it is more a result of choking, suffocation, or other causes of airway obstruction rather than a standalone measurement of CO2 levels. Ventilation, on the other hand, refers to the process of moving air in and out of the lungs but does not specifically denote the levels of carbon dioxide in the blood.