Final answer:
Increased ETCO₂ is often caused by conditions such as metabolic acidosis, Cushing's disease leading to metabolic alkalosis, or respiratory acidosis. Strenuous exercise and overfeeding can also contribute to raised ETCO₂ levels. Diagnosis and management depend on identifying the underlying cause.
Step-by-step explanation:
ETCO₂, or end-tidal CO₂, can increase due to several physiological and pathological conditions. Some of the key causes include metabolic acidosis, where an increase in carbon dioxide occurs as a result of conditions like diabetic ketoacidosis, uremia, or ingestion of certain substances such as an aspirin overdose. In conditions like Cushing's disease, chronic metabolic alkalosis can develop due to the chronic hypersecretion of ACTH leading to elevated aldosterone levels and an increased loss of potassium which affects CO₂ retention. Additionally, respiratory acidosis can lead to an increased CO₂ level in the blood due to impaired lung function from diseases such as pneumonia or emphysema.
Other contributing factors to increased ETCO₂ include a decrease in body temperature, decreased pH of the blood, increased exercise, and overfeeding leading to lipogenesis. It's important to note that a rise in atmospheric CO₂ levels, such as those caused by the Industrial Revolution, does not directly affect ETCO₂ but rather reflects a global environmental concern.