What does hypercapnia signify in a medical context?

Hypercapnia refers to an elevated level of carbon dioxide (CO2) in the blood, indicating that the body is not effectively removing carbon dioxide during respiration. This condition typically arises due to respiratory issues that hinder proper gas exchange in the lungs, leading to an accumulation of CO2. The correct answer reflects this understanding, as it identifies excessive carbon dioxide as the key factor in hypercapnia.

Understanding hypercapnia is crucial in medical practice because it often signals underlying respiratory problems such as chronic obstructive pulmonary disease (COPD), asthma, or respiratory failure, which may require prompt intervention.

The other options indicate conditions unrelated to hypercapnia. For example, excessive oxygen in the blood pertains to oxygen levels rather than carbon dioxide levels. Low levels of carbon dioxide are referred to as hypocapnia, while increased white blood cell activity is related to immune responses rather than gas exchange processes. Hence, distinguishing hypercapnia specifically focuses on the presence of excess carbon dioxide.