Question 1

All of the following can help avoid the problem of arterial blood sample contamination with air except:

Accepted Answer

Mixing the sample before expelling air does not help avoid contamination with air; it could actually increase the risk of air bubbles being incorporated into the sample. The other options directly address preventing or removing air from the sample.

Question 2

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? I.The pulmonary artery catheter balloon was not deflated. II.The sample was drawn from the proximal, not distal port. III.The blood sample was withdrawn too quickly.

Accepted Answer

The answer of A mixed venous blood sample obtained from...

Question 3

All of the following are TRUE about capillary blood gas sampling except:

Accepted Answer

A capillary sample provides a fairly close estimate of actual arterial oxygenation. However, it is important to note that while capillary blood gas sampling can provide estimates of arterial pH and PCO2 levels, clinicians should exercise caution when using capillary samples to guide decisions. Further, capillary sampling is not always appropriate and arterial access may still be necessary in certain situations.

Question 4

What is a normal level for CaO₂?

Accepted Answer

A normal CaO₂ is 18 to 20 ml of oxygen per 100 ml of arterial blood.

Question 5

After obtaining an arterial blood sample from an arterial line, you would do all of the following except:

Accepted Answer

Aspirating at least 5 ml of fluid or blood (dead space or waste) is typically done before obtaining the sample to ensure that the sample is not contaminated with saline or heparin from the line, not after obtaining the sample. The other options are correct post-procedure steps to ensure the line's patency and accuracy of the monitoring system.

Question 6

An outpatient scheduled for an arterial blood sample enters the pulmonary lab 20 minutes late and out of breath, having run up four flights of stairs. What should you do?

Accepted Answer

Waiting 5 minutes will give the patient some time to recover from running up the stairs, reducing the chances of inaccurate results due to hyperventilation. Postponing the blood sample until tomorrow or scolding the patient are not necessary or constructive responses, and scolding the patient for using the stairs may discourage them from engaging in physical activity.

Question 7

When is capillary blood gas sampling indicated?

Accepted Answer

Capillary blood gas sampling is indicated when ABG analysis is needed but arterial access is not available. Capillary blood can be obtained through a minimally invasive procedure and it provides a close approximation of arterial blood gas values.

Question 8

All of the following must be charted after obtaining an ABG sample through the brachial artery except:

Accepted Answer

The answer of All of the following must be charted...

Question 9

Capillary puncture should NOT be performed at or through what location?
I.inflamed or edematous tissue
II.localized areas of infection
III.the fingers of neonates
IV.previous puncture sites

Accepted Answer

Capillary puncture should not be performed at or through inflamed or edematous tissue, localized areas of infection, the fingers of neonates, or previous puncture sites to avoid contamination, injury, or inaccurate results.

Question 10

Possible complications of capillary blood gas sampling include all of the following except:

Accepted Answer

The possible complications of capillary blood gas sampling include infection, hematoma, and hemorrhage but not hypotension. Hypotension is not a common complication of this procedure.

Question 11

A PaO₂ below what value would be considered severe hypoxemia?

Accepted Answer

A PaO2 below 40 mm Hg is considered severe hypoxemia regardless of the FIO2.

Question 12

To assess gas exchange at the tissues, you would obtain a blood sample from which of the following?

Accepted Answer

The answer of To assess gas exchange at the tissues,...

Question 13

You determine that a blood gas sample that requires analysis has been sitting in an ice slush for 90 minutes. What should you do?

Accepted Answer

Blood gas samples should be analyzed immediately or within the time frame recommended by the manufacturer. If a blood gas sample has been sitting in ice slush for 90 minutes, it is likely that there has been a change in the gas concentrations and pH, which could potentially affect patient care. The best course of action is to discard the sample and notify the appropriate clinician.

Question 14

A physician requests that you obtain and set up an arterial line system for invasive monitoring of blood pressure. Which of the following equipment would you gather?
I.pressurized intravenous bag
II.continuous flush device
III.arterial catheter
IV.pressure transducer
V.amplifier or monitor

Accepted Answer

Setting up an arterial line system for invasive blood pressure monitoring requires a pressurized intravenous bag to maintain a constant flush, a continuous flush device to prevent clot formation at the catheter tip, an arterial catheter for insertion into the artery, a pressure transducer to convert the arterial pressure into an electrical signal, and an amplifier or monitor to display the blood pressure readings.

Question 15

Analysis of an arterial blood sample taken from a healthy athlete reveals a pH of 7.36, a PCO₂of 45 mm Hg, and a PO₂ of 43 mm Hg. Which of the following analytic errors should you suspect?

Accepted Answer

The pH, PCO2, and PO2 values in arterial blood differ from those in venous blood, and mixing arterial and venous blood can lead to inaccurate measurements. Thus, the analytical error that should be suspected in this case is admixture with venous blood.

Question 16

What is the best site for capillary puncture in an infant?

Accepted Answer

The lateral aspect of the heel's plantar surface is the most common site for capillary puncture in infants. It offers good blood flow and is less painful for the infant compared to other sites. Other sites may have less blood flow, cause discomfort or be prone to tissue damage.

Question 17

Warming a capillary bed to 42° C has which of the following effects?
I.It constricts the underlying blood vessels.
II.It increases blood flow well above tissue needs.
III.It "arterializes" the capillary blood.

Accepted Answer

Warming a capillary bed to 42° C increases blood flow well above tissue needs (hyperemia) and "arterializes" the capillary blood, meaning it increases the oxygen content to more closely resemble arterial blood. It does not constrict the underlying blood vessels; instead, it dilates them, which is contrary to option I.

Question 18

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?

Accepted Answer

The answer of Because of an extremely low PO₂, you...

Question 19

Before connecting the sample syringe to an adult's arterial line stopcock, what would you do?

Accepted Answer

Aspirating at least 5 ml of fluid or blood using a waste syringe helps to clear any air bubbles or debris in the line that could contaminate the sample or cause harm to the patient. It is important to follow the proper aseptic technique while doing this. Options A, C, and D may also be done, but they are not the best choices before connecting the sample syringe.

Question 20

Through which pulmonary artery catheter port would you obtain a mixed venous blood sample?

Accepted Answer

The mixed venous blood sample is obtained from the distal (catheter tip) port of the pulmonary artery catheter. This port is positioned in the pulmonary artery and represents mixed venous blood from the body tissues. A sample from this port can give information about the adequacy of oxygen delivery to the tissues.

Quiz 18: Analysis and Monitoring of Gas Exchange

All of the following can help avoid the problem of arterial blood sample contamination with air except:

All of the following are TRUE about capillary blood gas sampling except:

What is a normal level for CaO2?