What action should be taken if increasing PECO2 is observed with stable SpO2 in a mechanically ventilated patient?

The appropriate action in response to an increasing end-tidal carbon dioxide (PECO2) level alongside stable oxygen saturation (SpO2) in a mechanically ventilated patient is to assess for possible dead space ventilation.

Dead space is the portion of the respiratory system where gas exchange is not occurring, meaning that even though the patient is ventilated, not all of the exhaled air is participating in effective gas exchange. An increase in PECO2 indicates that carbon dioxide is being retained, which can occur when there are regions within the lungs that are ventilated but not perfused (such as in cases of pulmonary embolism or certain types of lung disease). This retention of carbon dioxide can lead to hypercapnia, which needs to be addressed to maintain proper acid-base balance and overall respiratory function.

In contrast, increasing tidal volume might not effectively address the underlying issue of impaired gas exchange if there is significant dead space. Checking the patient's inspiratory effort may not provide relevant information regarding PECO2 levels, particularly if the patient is already sufficiently ventilated. Decreasing the respiratory rate could further exacerbate the already elevated CO2 levels, counterproductive to the goal of maintaining proper ventilation.

Thus, assessing for dead space will help in identifying if there's