Exam 19: Analysis and Monitoring of Gas Exchange

Indications for pulse oximetry include which of the following? 1) To assess changes in HbO₂ during certain procedures 2) To measure abnormal Hb 3) To comply with external regulations or recommendations 4) To monitor the adequacy of HbO₂ saturation

The shape of the expired CO₂ tracing of a patient is normal but instead of being zero, the baseline is elevated to approximately 12 mm Hg. Which of the following is the most likely problem?

To avoid the dilution effects caused by too much sodium heparin during ABG sampling of an adult, what should you do? 1) Ensure a sample volume greater than 2 ml. 2) Use dry heparin instead. 3) Fill the needle dead space only. 4) Use saline if dry heparin is not available.

While analyzing a blood gas control sample, you notice a trending of several PCO₂ values above the 2 SD range over the last six control samples run. What corrective action would you consider at this time? 1) Check the function of the PCO₂ electrode. 2) Rerun the control sample a second time. 3) Repair or replace any failed components.

Under ideal conditions, electrochemical oxygen (O₂) analyzers have approximately what degree of accuracy?

A mixed venous blood sample obtained from a pulmonary artery catheter sample has a PO₂ of 85 mm Hg and a hemoglobin saturation of 95%. Which of the following is likely? 1) The pulmonary artery catheter balloon was not deflated. 2) The sample was drawn from the proximal, not distal port. 3) The blood sample was withdrawn too quickly.

While monitoring an active infant through a transcutaneous blood gas system, you notice a rapid rise in P_tcO₂ from 63 to 145 mm Hg. At that same time, the (P_tcCO₂) drops from 35 to 7 mm Hg. What is the most appropriate action in this case?

Which of the following Centers for Disease Control and Prevention (CDC) barrier precautions would you use when obtaining an arterial blood gas (ABG) through percutaneous puncture? 1) Gloves 2) Protective eyewear 3) Gown or apron

Under ideal conditions, pulse oximeter readings patients usually fall in what range of those obtained with invasive hemoximetry?

To measure PCO₂, blood gas analyzers use what electrode?

Which of the following sites are used for arterial blood sampling by percutaneous needle puncture? 1) Femoral 2) Radial 3) Brachial 4) Carotid

Before a sample of capillary blood is taken, what should you do to the site? 1) Warmed to 42° C for 10 min. 2) Squeezed lightly until blanched. 3) Cleaned with an antiseptic solution.

Which of the following factors does not contributing to bias (systematic) errors during blood gas analysis?

What is the process of testing a new blood gas analyzer to confirm a manufacturer's claims?

During calibration of a Clark polarographic O₂ analyzer, you cannot get the sensor to read 100% when exposed to 100% O₂, even after adjusting its calibration control. The unit has new batteries. Which of the following actions would be correct?

How does the Clark polarographic O₂ electrode function?

Which blood gas analyzer electrode uses a separate reference electrode?

You return to a patient's room 20 min after drawing an ABG. Which of the following should you check at this time? 1) Puncture site for hematoma 2) Adequacy of distal circulation 3) Prothrombin or partial thromboplastin times

Because of an extremely low PO₂, you suspect that an arterial blood sample taken from a patient's brachial artery might have been contaminated with venous blood. Which of the following might help to confirm your suspicion?

Which of the following guidelines should you adhere to when performing pulse oximetry? 1) Mix different sensors among different devices to ensure accuracy. 2) Make sure that the sensors are the correct size and are properly applied. 3) Avoid using pulse oximetry to monitor hyperoxia in neonates. 4) Whenever possible, validate the initial SpO₂ against the actual SaO₂.