Certified Respiratory Therapist Practice Exam

If an infant's transcutaneous monitor shows a rapid rise in PtCO2, what is a likely cause of the problem?

1. Sensor malfunction

2. Incorrect settings on the monitor

3. Air leak around the sensor's adhesive ring

4. Insufficient skin preparation

The correct answer is: Air leak around the sensor's adhesive ring

A rapid rise in PtCO2 on a transcutaneous monitor in an infant is often indicative of an air leak around the sensor's adhesive ring. This leak can prevent accurate measurements, as the sensor relies on a stable environment to effectively monitor carbon dioxide levels in the skin. When air escapes around the sensor, it can lead to misleading readings that suggest an increase in CO2 levels, even if the actual physiological condition of the infant is stable. The adhesive ring is crucial for ensuring that the sensor is in full contact with the skin, which allows for the proper diffusion of gases and accurate monitoring. Without this seal, the monitored values become unreliable, leading to a false interpretation of the infant's respiratory status. The choice of sensor malfunction could suggest a defect in the device itself, but it would be less common than issues related to the interface between the sensor and the skin. Incorrect settings might also lead to inaccuracies, yet it is more likely that a physical disruption, such as an air leak, would be the immediate cause of the rise in PtCO2. Insufficient skin preparation can also affect readings, but it typically leads to a slower response rather than a rapid change.