What could cause an inaccurate exhaled CO2 reading on a capnograph in a ventilator circuit?

An inaccurate exhaled CO2 reading on a capnograph can occur when the infrared detector is soiled. The infrared detector is essential for measuring the concentration of carbon dioxide in the exhaled breath, and if it becomes dirty or obstructed with contaminants, it can interfere with the detection of CO2 levels. This obstruction may prevent the detector from accurately assessing the infrared light spectrum it needs to measure the presence of CO2, leading to erroneous readings that may not reflect the patient's actual metabolism or ventilation status.

While other factors can affect readings, such as ambient light, polycythemia, or excessive gas temperatures, these factors do not directly impact the functioning of the infrared detector itself in the same manner that soiling does. Therefore, maintaining a clean infrared detector is crucial for ensuring the accuracy of capnography in clinical settings.