A galvanic fuel cell oxygen analyzer may inaccurately read high under which condition?

• A. During a sudden increase in the partial pressure of oxygen
• B. When liquid gets on the membrane
• C. When the analyzer batteries are depleted
• D. When a volume-controlled ventilator at high inspiratory pressures

Answer: (D)

The correct answer highlights a specific condition that can lead to inaccurate readings in a galvanic fuel cell oxygen analyzer. When a volume-controlled ventilator operates at high inspiratory pressures, this can affect the flow dynamics and the gas mixture that reaches the analyzer. In these scenarios, the high pressures can complicate the diffusion of oxygen to the sensing electrode, causing a discrepancy between the actual oxygen levels and what the analyzer indicates. This can result in an inaccurate high reading.

Other factors, such as sudden changes in oxygen partial pressure and liquid contact with the membrane, can also lead to inaccuracies, but the volume-controlled ventilator scenario is particularly impactful because it alters the mechanical aspects of gas delivery. Similarly, depleted analyzer batteries can affect performance, yet they do not specifically cause elevated readings as high pressures can. Each of these conditions presents challenges to the accurate function of the analyzer, but the interplay of high inspiratory pressures with the analyzer's response mechanism specifically contributes to the inaccuracies in the measurement of oxygen levels.