In the context of anesthesia, what might increased ETCO2 indicate?

Increased end-tidal carbon dioxide (ETCO2) levels typically indicate hypoventilation. This phenomenon occurs when the rate of carbon dioxide production in the body exceeds the rate at which it is being eliminated through respiration, leading to an accumulation of CO2 in the bloodstream and, subsequently, in the exhaled air.

Hypoventilation can result from a variety of factors, including respiratory depression, sedation, or muscle relaxation induced by anesthesia. When a patient is under anesthesia, their respiratory drive may be reduced, leading to shallow or infrequent breaths. As a consequence, the carbon dioxide produced by the metabolism remains in the lungs longer than it should, resulting in higher ETCO2 readings.

In contrast, conditions such as hyperventilation would lead to decreased ETCO2 since increased respiratory rate and depth would cause more CO2 to be expelled. Similarly, decreased cardiac output primarily affects the perfusion and delivery of CO2 to the lungs but does not directly cause an increase in ETCO2. Increased oxygen demand may occur under stress or heavy activity, but it is not directly related to increased ETCO2 levels either.