Answer :
Final answer:
The most appropriate and cost-effective action to address concerns about the accuracy of PO2 readings in a blood gas machine is to perform a two-point calibration, ensuring device accuracy across the entire physiological range.
Explanation:
When a respiratory therapist is concerned about the accuracy of the reportable physiological range of the PO₂ electrode in a blood gas machine, the most appropriate action would be to perform a two-point calibration. This process involves using two known standard values to ensure the accuracy of the device across the range of expected physiological measurements. One-point calibration could adjust the device's accuracy at a single point, which might not be sufficient for covering the entire physiological range. On the other hand, replacing the PO₂ electrode or the Sanz electrode could be unnecessary and costly actions without first attempting recalibration. Moreover, recalibration aligns with the principle of ensuring medical equipment is accurately calibrated for patient safety and accurate diagnostic results, as indicated by the guideline to standardize pH electrodes with multiple buffers.