Deck 8: Invasive Blood Gas Analysis and Cardiovascular Monitoring

Question 1

On the basis of the position of the three-way stopcock shown here, identify which of the following activities related to arterial lineblood sampling is occurring.

A) The therapist is aspirating blood diluted with infusion fluid.
B) The therapist is withdrawing blood from the arterial line.
C) The therapist is keeping the stopcock in its normal operational position.
D) The therapist is infusing fluid back into the system after having removed a blood sample.

Answer 1

C
What is depicted by the position of the three-way stopcock is the system's normal operating position with the flush, or infusion, solution going to the patient while the sample port is closed.

Question 2

A 12-hour-old infant is experiencing respiratory distress, and the neonatologist orders a heel stick to assess the infant's oxygenation status. What action should the therapist take at this time?

A) Perform the heel stick as ordered.
B) Instead of using the newborn's heel, the therapist should use a finger as the site.
C) Inform the physician that this procedure is inappropriate at this time.
D) Explain to the doctor that an arterial puncture procedure is appropriate.

Answer 2

C
A capillary puncture is contraindicated in neonates less than 24 hours old. A newborn has a low systemic output, and vasoconstriction tends to be maximal during this stage secondary to a decrease in environmental temperature and an increase in circulating catecholamines. Capillary blood sampling is not recommended in a patient with decreased peripheral blood flow, especially in the case of hypotension.

Question 3

Calculate a patient's total arterial oxygen content given the following data:
$\bullet$ Arterial oxygen tension (PaO₂), 100 mm Hg
$\bullet$ Arterial carbon dioxide tension (PaCO₂), 45 mm Hg
$\bullet$ Arterial oxygen saturation (SaO₂), 97.5%
$\bullet$ Hemoglobin concentration ([Hb]), 15 g/dL
$\bullet$ Cardiac output, 4.5 L/minute
$\bullet$ Stroke volume, 55 mL/beat

A) 19.9 vol%
B) 18.7 vol%
C) 16.6 vol%
D) 14.9 vol%

Answer 3

19.9 vol%

Question 4

On the basis of the following waveform, in which of the following anatomic locations is the distal tip of the pulmonary artery catheter located?

A) Right atrium
B) Right ventricle
C) Pulmonary artery
D) Wedged position

Question 5

Which of the following factors would adversely affect the correlation between arterial puncture measurements and those from a capillary sample?

A) Hypotension
B) Hyperventilation
C) Hypoxemia
D) Hyperthermia

Question 6

On the basis of the following waveform, in which of the following anatomic locations is the distal tip of the pulmonary artery catheter located?

A) Right atrium
B) Right ventricle
C) Pulmonary artery
D) Wedged position

Question 7

Which of the following factors influence the central venous pressure (CVP) measurement?
I) Bicuspid valve function
II) Right ventricular pressure
III) Intravascular volume
IV) Systemic venous return

A) I and III only
B) II and III only
C) I, II, and IV only
D) II, III, and IV only

Question 8

Which of the following arteries is considered the optimal puncture site for obtaining arterial blood samples from a pediatric patients?

A) Radial artery
B) Axillary artery
C) Ulnar artery
D) Popliteal artery

Question 9

Which of the following pulmonary artery catheter waveforms represents the catheter's normal location?

A) Right atrium
B) Right ventricle
C) Pulmonary artery
D) Wedged position

Question 10

A patient has a systolic blood pressure of 100 mm Hg and a diastolic pressure of 75 mm Hg. What is this patient's mean arterial pressure?

A) 25 mm Hg
B) 58 mm Hg
C) 83 mm Hg
D) 175 mm Hg

Question 11

With an umbilical artery catheter (UAC) in the "low position," which of the following blood vessels should be avoided?

A) Celiac artery
B) Superior mesenteric artery
C) Renal artery
D) Descending aorta

Question 12

A respiratory therapist has been ordered to obtain a blood gas sample from a nonintubated premature baby. After selecting the best site to obtain the sample, what should the RT suggest to ameliorate the pain associated with the procedure?

A) Administer a small dose of fentanyl
B) Inject lidocaine at the injection site
C) Give a pacifier dipped in 24% sucrose
D) Administer a lidocaine drip

Question 13

Which of the following conditions can cause methemoglobinemia?

A) Anemia
B) Inhalation of nitric oxide (NO)
C) Use of dobutamine
D) High fraction of inspired oxygen

Question 14

The neonatal intensive care unit (NICU) respiratory therapy supervisor is observing a therapist obtain an arterial blood sample from an infant's radial artery and notices that the therapist has the bevel of the needle pointed upward, entering the patient's skin at a 45-degree angle and in a direction against the arterial flow. What should the supervisor do at this time?

A) Continue to observe the procedure.
B) Inform the therapist to turn the bevel downward.
C) Tell the therapist to penetrate the infant's skin at about a 60-degree angle.
D) Advise the therapist to insert the needle in the same direction as the blood flows.

Question 15

In addition to the dorsalis pedis, which of the following arteries is involved when the modified Allen's test is performed using a foot as the potential arterial puncture site?

A) Axillary artery
B) Femoral artery
C) Posterior tibial artery
D) A modified Allen's test cannot be done using a foot

Question 16

A 3-kg neonate has lost 30% of his circulating blood volume. Approximately how much fluid should be infused to compensate for this loss?

A) 30 mL
B) 60 mL
C) 90 mL
D) 120 mL

Question 17

If a blood gas sample is not obtained from an arterial stick in a premature baby without central access, which of the following sites should be considered because this blood vessel is larger than the radial artery at this age?

A) Dorsalis pedis
B) Temporal
C) Posterior tibial
D) Femoral

Question 18

Which of the following is one of the most common arrhythmias observed as a complication from the insertion of a pulmonary artery catheter?

A) Premature ventricular contraction
B) S3 gallop
C) Atrial fibrillation
D) Paroxysmal atrial contraction

Question 19

On the basis of the following waveform, in which of the following anatomic locations is the distal tip of the pulmonary artery catheter located?

A) Right atrium
B) Right ventricle
C) Pulmonary artery
D) Wedged position

Question 20

How would tricuspid stenosis be expected to influence a patient's CVP value?

A) Elevate it above normal
B) Cause it to fall below normal
C) Produce fluctuations in the CVP value
D) Have no effect in the CVP value

Question 21

Which of the following will cause a right shift in the oxyhemoglobin dissociation curve?

A) Fetal hemoglobin
B) Methemoglobin
C) Carboxyhemoglobin
D) High levels of 2,3-diphosphoglycerate