Certified Respiratory Therapist Practice Exam

What findings suggest air leaks significantly impact a transcutaneous monitoring reading?

1. Elevated PtCO2 with normal PO2

2. Low PtCO2 with PO2 around 150 torr

3. Consistent high readings in both PtCO2 and PtCCO2

4. All readings are within normal limits

The correct answer is: Low PtCO2 with PO2 around 150 torr

The correct option indicates a situation where there is a low transcutaneous carbon dioxide (PtCO2) reading, while the arterial or transcutaneous partial pressure of oxygen (PO2) is significantly elevated, around 150 torr. This discrepancy can suggest that there is an air leak affecting the transcutaneous monitoring. Transcutaneous monitoring relies on the integrity of the skin sensor to accurately reflect the gas exchange occurring in the body. An air leak can disrupt the sensor's ability to measure carbon dioxide levels accurately, leading to a PtCO2 reading that does not correlate with the arterial or expected values. A low PtCO2 in the presence of a high PO2 indicates that the monitor may not be capturing the true CO2 levels, possibly due to external air entering the system. This finding highlights the importance of maintaining a closed system in transcutaneous monitoring to ensure reliable results. When air leaks disrupt this balance, it often results in misleading readings, particularly where CO2 levels are concerned, as CO2 is more soluble and affected by the presence of air compared to oxygen. The other answer choices do not suggest significant impact from air leaks as clearly. High readings in PtCO2 and PtCCO2 (the option describing consistent high readings) could indicate adequate