Certified Respiratory Therapist Practice Exam

Which method is best to assess tissue oxygenation in a patient with ARDS?

1. Transcutaneous Oximetry

2. Arterial Blood Gas Analysis

3. Pulmonary Artery Catheter

4. Peripheral Blood Gas Analysis

The correct answer is: Pulmonary Artery Catheter

The best method to assess tissue oxygenation in a patient with Acute Respiratory Distress Syndrome (ARDS) is through the use of a pulmonary artery catheter. This technique allows for direct measurement of various hemodynamic parameters, including pulmonary artery pressures and cardiac output, which can provide valuable insights into a patient's respiratory and circulatory status. In ARDS, tissue oxygenation can be significantly compromised due to impaired gas exchange and altered hemodynamics. A pulmonary artery catheter can help clinicians determine the effectiveness of ventilation and perfusion matching, as well as the overall oxygen delivery to tissues. It provides a more comprehensive view of a patient's condition compared to other methods by allowing for continuous monitoring and assessment of right heart pressures and mixed venous oxygen saturation, which is crucial in evaluating oxygen delivery and consumption at the cellular level. The other methods, while useful for various purposes, do not directly assess tissue oxygenation as effectively. Transcutaneous oximetry measures peripheral oxygen levels and can be influenced by skin perfusion, making it less reliable in critically ill patients. Arterial blood gas analysis provides valuable information on blood gases but is more focused on respiratory function rather than direct tissue oxygenation. Peripheral blood gas analysis provides limited information on oxygen delivery to tissues compared to mixed ven