Deck 18: Analysis and Monitoring of Gas Exchange

Question 1

Patient parameters that should be assessed as part of arterial blood sampling include all of the following except:

A)blood pressure
B)temperature
C)position or activity level
D)clinical appearance

Answer 1

A

Question 2

While checking a galvanic fuel cell O₂ analyzer, you determine that the device fails to read 100% when exposed to pure O₂. Which of the following actions would be the proper first step?

A)Check the silica crystals.
B)Send the device out for repair.
C)Replace the analyzer's batteries.
D)Change the analyzer's fuel cell.

Answer 2

C

Question 3

Why is the radial artery the preferred site for arterial blood sampling?
I.It is near the surface and easy to palpate and stabilize.
II.The ulnar artery normally provides good collateral circulation.
III.The radial artery is not near any large veins.

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

Answer 3

I, II, and III

Question 4

Which of the following should be monitored during the sampling of arterial blood?
I)blood pressure proximal to puncture site
II)presence of pulsatile blood return
III)presence of air bubbles or clots in sample
IV)appearance of puncture site

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

Question 5

What size needle would you recommend to obtain an ABG sample through percutaneous puncture of an infant?

A)18 gauge
B)20 gauge
C)22 gauge
D)25 gauge

Question 6

Purposes of a needle-capping device include which of the following?
I)to isolate the sample from air exposure
II)to help prevent needlestick injuries
III)to hold the excess anticoagulant

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

Question 7

All of the following are grounds for finding an alternative site for arterial puncture except:

A)negative modified Allen test
B)history of peripheral vascular disease
C)anticoagulation therapy
D)presence of a surgical shunt

Question 8

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

A)1%
B)2%
C)3%
D)4%

Question 9

How does the Clark polarographic O₂ electrode function?

A)measures the magnetic properties of O₂ versus N₂
B)measures the electrical potential across a Wheatstone bridge
C)uses O₂ to produce a reduction-oxidation reaction
D)measures the comparative cooling effect on a heated wire

Question 10

All of the following sites are used for arterial blood sampling by percutaneous needle puncture except:

A)femoral
B)radial
C)brachial
D)carotid

Question 11

You are asked to provide continuous monitoring of the FIO₂ provided by a humidified O₂ delivery system using a galvanic cell analyzer. Where would you install the analyzer's sensor?

A)proximal to the heated humidifier
B)on the expiratory side of the circuit
C)distal to the heated humidifier
D)as close to the patient as possible

Question 12

Required equipment and supplies for percutaneous arterial blood sampling of an adult include all of the following except:

A)antiseptic (alcohol or Betadine)
B)patient or sample label
C)20- to 22-gauge needle
D)local anesthetic

Question 13

Indications for arterial blood sampling by percutaneous needle puncture include all of the following except the need to:

A)monitor the severity of a disease process
B)assess the adequacy of tissue oxygenation
C)evaluate ventilation and acid-base status
D)evaluate a patient's response to therapy

Question 14

Which of the following is FALSE about the galvanic fuel cell O₂ analyzer?

A)It actually measures the PO₂ and not the O₂ concentration.
B)It requires an external power source (alternating current line or batteries).
C)It has a slower response time than the Clark electrode.
D)Its fuel cells deplete and must be periodically replaced.

Question 15

Precautions and/or possible complications of arterial puncture include which of the following?
I)arteriospasm
II)embolization
III)infection
IV)hemorrhage

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

Question 16

Which of the following is false about invasive versus noninvasive monitoring?

A)Invasive procedures require insertion of a device into the body.
B)Laboratory analysis of gas exchange is usually noninvasive in nature.
C)Physiologic monitoring can be either invasive or noninvasive.
D)Invasive procedures provide more accurate data but carry greater risks.

Question 17

After obtaining an arterial blood sample through percutaneous puncture using a syringe that does not have a capping safety device, what should you do?

A)Remove the needle with a Kelly clamp, then plug the syringe.
B)"Scoop" the needle cap up with one hand, then plug the syringe.
C)Force the needle into a rubber cork or plastic stopper.
D)Manually remove and bend the needle, then plug the syringe.

Question 18

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?
I)gloves
II)protective eyewear
III)gown or apron

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

Question 19

Treatment parameters that should be assessed as part of arterial blood sampling include all of the following except:

A)mode of ventilatory support and settings
B)time of last incentive breathing exercise
C)FIO₂ (analyzed) or prescribed flow
D)proper application of the O₂ device

Question 20

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?

A)Use it only with low Fio₂ values.
B)Send the device out for repair.
C)Replace the unit's batteries.
D)Change the sensor or electrode.

Question 21

All of the following factors determine the volume needed for an arterial blood sample except:

A)ABG analyzer's requirements
B)specific anticoagulant used
C)site used for sampling
D)other tests that will be needed

Question 22

Which of the following describes the correct procedure for an Allen test?

A)Compress both the radial and ulnar arteries, then release the radial artery.
B)Compress both the radial and ulnar arteries, then release the ulnar artery.
C)Compress both the radial and ulnar arteries, then release both arteries at once.
D)Compress the brachial artery only and observe circulation to the hand.

Question 23

What chart information should be checked before performing artery puncture?
I)patient's primary diagnosis and history
II)presence of bleeding disorders or blood-borne infections
III)anticoagulant or thrombolytic drug prescriptions
IV)respiratory care orders (e.g., O₂ therapy)

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

Question 24

To avoid transmission of blood-borne diseases when handling a used needle, what should you do?
I.Never recap the needle without a safety device (or scoop method).
II.Never handle the needle with both hands, or point it toward the body.
III.Never bend, break, or remove the needle from the syringe by hand.
IV.Always dispose of the syringe or needle in a proper sharps container.

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

Question 25

When performing a percutaneous needle puncture of the radial artery, you get only a small spurt of blood. Which of the following is the best action at this time?

A)Slowly withdraw the needle until a pulsatile flow fills the syringe.
B)Pull out entirely, use a different angle and then reinsert it.
C)Slowly advance the needle until a pulsatile flow fills the syringe.
D)Repeat the procedure with a fresh blood gas kit.

Question 26

Which of the following changes would occur if an arterial blood sample of a patient breathing room air were exposed to a large air bubble?
I)decreased PCO₂
II)decreased pH
III)increased PO₂

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

Question 27

Which of the following would you expect to occur if too much heparin was used in gathering an ABG sample from a patient breathing room air?

A)increase in HCO₃^-
B)decrease in PCO₂
C)decrease in pH
D)decrease in PO₂

Question 28

To avoid the dilution effects caused by too much sodium heparin during ABG sampling of an adult, what should you do?
I.Ensure a sample volume greater than 2 ml.
II.Use dry heparin instead.
III.Fill the needle dead space only.

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

Question 29

A practitioner forgets to ice an ABG sample and leaves it at room temperature for 45 minutes. Which of the following parameters can you predict will increase in this sample during that period?
I)PCO₂
II)pH
III)PO₂

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

Question 30

When performing a modified Allen test on the left hand of a patient, you notice that the palm, fingers, and thumb remain blanched for more than 15 seconds after pressure on the ulnar artery is released. What should you do?

A)Use the brachial site for sampling.
B)Sample from the contralateral radial artery.
C)Use the femoral site for sampling.
D)Perform the Allen test on the right hand.

Question 31

Which of the following indicates venous admixture during arterial puncture?
I)need to use syringe suction
II)dark-colored blood
III)small sample volumes

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

Question 32

All of the following conditions make interpreting the results of a modified Allen test difficult except:

A)dark skin pigmentation
B)severe circulatory insufficiency
C)burns about the wrists or hands
D)systemic jaundice

Question 33

Before performing puncture or cannulation of the radial artery, what should you do?

A)Fix and tighten a tourniquet above the antecubital fossa.
B)Perform the Allen test to ensure collateral circulation.
C)Inject heparin into the adjoining subcutaneous tissues.
D)Apply firm pressure to the arterial site for 5 minutes.

Question 34

How long should you wait before drawing an ABG on a chronic obstructive pulmonary disease (COPD) patient whose FIO₂ has just been changed?

A)5 to 10 minutes
B)10 to 15 minutes
C)15 to 20 minutes
D)20 to 30 minutes

Question 35

After obtaining an arterial blood sample, what should you do?
I.Apply pressure to the puncture site until bleeding stops.
II.Place the sample in a transport container with ice slush.
III.Check to see if the patient is getting anticoagulant therapy.
IV.Mix the sample by rolling and inverting the syringe.

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

Question 36

You return to a patient's room 20 minutes after drawing an ABG. Which of the following should you check at this time?
I)puncture site for hematoma
II)adequacy of distal circulation
III)prothrombin or partial thromboplastin times

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

Question 37

If patient pain or anxiety occurs during arterial puncture, which of the following will probably occur?

A)hypoventilation
B)hyperventilation
C)respiratory acidosis
D)hypoxemia

Question 38

You are asked to perform a radial artery puncture on an unconscious patient. How can you confirm the presence of collateral circulation?
I.Use a Doppler transducer to assess thumb blood flow with radial obstruction.
II.Use a pulse oximeter to assess thumb blood flow with ulnar obstruction.
III.Use a pulse oximeter to assess thumb blood flow with radial obstruction.

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

Question 39

Most preanalytical ABG errors can be avoided by ensuring that the sample is which of the following?
I)properly anticoagulated
II)obtained anaerobically
III)analyzed within 15 minutes

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

Question 40

When analyzing an ABG sample from a patient with acute respiratory distress syndrome and refractory hypoxemia, you notice a PaO₂ of 141 mm Hg and a PaCO₂ of 14 mm Hg. Which of the following analytic errors should you suspect?

A)excessive time since sample collection
B)exposure of the blood sample to air
C)excessive heparin in the sample
D)sample admixture with venous blood

Question 41

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

A)discarding frothy samples
B)fully expelling any bubbles
C)mixing before expelling air
D)capping syringe quickly

Question 42

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.

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

Question 43

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

A)Capillary sampling can be used in lieu of direct arterial access in some infants and small children.
B)A capillary sample PO₂ provides a fairly close estimate of actual arterial oxygenation.
C)Clinicians should exercise caution when using capillary samples to guide decisions.
D)Properly obtained capillary blood can provide estimates of arterial pH and PCO₂ levels.

Question 44

What is a normal level for CaO₂?

A)12 to 15 ml/100 ml
B)14 to 16 ml/100 ml
C)18 to 20 ml/100 ml
D)16 to 22 ml/100 ml

Question 45

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

A)Flush the line and stopcock with the heparinized intravenous solution.
B)Aspirate at least 5 ml of fluid or blood (dead space or waste).
C)Confirm stopcock port open to intravenous bag solution and catheter.
D)Confirm undamped pulse pressure waveform on monitor.

Question 46

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?

A)Postpone the blood sample until tomorrow.
B)Scold the patient for being so late.
C)Wait 5 minutes before taking the sample.
D)Scold the patient for using the stairs.

Question 47

When is capillary blood gas sampling indicated?

A)There is a need for direct analysis of blood oxygenation.
B)Normal noninvasive monitor readings need to be checked.
C)ABG analysis is needed, but arterial access is not available.
D)Continuous data on patient ventilation status are needed.

Question 48

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

A)patient's temperature, position, activity level
B)date, time, and site of sampling
C)inspired O₂ concentration or ventilator settings
D)results of the modified Allen test

Question 49

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

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

Question 50

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

A)infection
B)hematoma
C)hemorrhage
D)hypotension

Question 51

A PaO₂ below what value would be considered severe hypoxemia?

A)60 mm Hg
B)50 mm Hg
C)40 mm Hg
D)depends on the FIO₂

Question 52

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

A)pulmonary artery (balloon-deflated)
B)peripheral artery (radial, brachial)
C)central vein (superior or inferior vena cava)
D)pulmonary artery (balloon-inflated)

Question 53

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

A)Go ahead and analyze the sample (because it was on ice).
B)Warm the sample to room temperature before analysis.
C)Readjust the blood gas analyzer temperature to 0 ^$\circ$ C.
D)Discard the sample and notify the appropriate clinician.

Question 54

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

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

Question 55

Analysis of an arterial blood sample taken from a healthy athlete reveals a pH of 7.36, a PCO₂ of 45 mm Hg, and a PO₂ of 43 mm Hg. Which of the following analytic errors should you suspect?

A)excessive time since sample collection
B)exposure of the blood sample to air
C)excessive heparin in the sample
D)sample admixture with venous blood

Question 56

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

A)lateral aspect of the heel's plantar surface
B)anterior curvature of the heel
C)medial aspect of the heel's plantar surface
D)posterior curvature of the heel

Question 57

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.

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

Question 58

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?

A)Call the lab to get the latest chemistry report.
B)Inspect the sample for color and consistency.
C)Cross-check the sample with an SpO₂ reading.
D)Measure the sample's actual hemoglobin saturation.

Question 59

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

A)Flush the line and stopcock with the heparinized intravenous solution.
B)Aspirate at least 5 ml of fluid or blood using a waste syringe.
C)Align the stopcock off to the patient and on to the flush solution.
D)Increase the flush-solution bag pressure by 20 to 30 mm Hg.

Question 60

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

A)proximal (right atrium) port
B)catheter thermistor connector
C)distal (catheter tip) port
D)balloon inflation port

Question 61

Components of a laboratory blood gas analyzer include which of the following?
I)three-electrode measuring chamber
II)reagent containers
III)calibrating gas tanks
IV)waste container

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

Question 62

Statistically derived limits for internal quality control of blood gas samples are usually set at what appropriate level?

A)1 standard deviation from the mean
B)2 standard deviations from the mean
C)3 standard deviations from the mean
D)5 standard deviations from the mean

Question 63

When analyzing a blood gas control sample, you notice that the result falls outside the 2 SD range. How could you verify that this was a random error (error of imprecision)?
I.Repeat the analysis on a different analyzer.
II.Compare the control to an actual patient sample.
III.Rerun the control sample a second time.

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

Question 64

The total instrument error (inaccuracy) of a blood gas analyzer equals which of the following?

A)bias + imprecision
B)imprecision + random error
C)bias + systematic error
D)trend error + bias

Question 65

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?
I.Check the function of the PCO₂ electrode.
II.Rerun the control sample a second time.
III.Repair or replace any failed components.

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

Question 66

What media are used to calibrate a blood gas analyzer's gas electrodes?

A)standard pH buffer solutions
B)blood-like control media
C)precision mixtures of O₂ and CO₂
D)tonometered human blood samples

Question 67

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

A)automated calibration
B)performance validation
C)proficiency testing
D)preventive maintenance

Question 68

To ensure that the output of a blood gas analyzer is both accurate and linear across the range of measured values, a calibration procedure must measure what?

A)two different parameters at the same time
B)parameters with known input values at one point
C)two different parameters at different times
D)parameters with known input values at two points

Question 69

Factors contributing to bias (systematic) errors during blood gas analysis include all of the following except:

A)incorrect procedures
B)statistical probability
C)contaminated buffers
D)component failure

Question 70

When conducting ABG analysis in the laboratory, obvious signs of preanalytical error include all of the following except:

A)air bubbles
B)gross dilution
C)clotting
D)unmixed sample

Question 71

When inspecting an internal quality-control plot for a blood gas analyzer, you notice several data points sporadically appearing outside the 2 standard deviation (SD) range. This represents what type of analytic error?
I)random error
II)bias
III)imprecision
IV)systematic error

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

Question 72

Which blood gas analyzer electrode uses a separate reference electrode?

A)O₂
B)pH
C)Clark
D)HCO₃^-

Question 73

To measure PCO₂, blood gas analyzers use what electrode?

A)Severinghaus
B)Clark
C)Sahn
D)White

Question 74

Which of the following are TRUE about a blood gas analyzer's waste fluids?
I.A strong disinfectant should be added to waste fluid containers.
II.Waste fluids should be handled as if they were blood samples.
III.Waste fluids should be treated as potentially infectious.

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

Question 75

How often should blood gas calibration verification by control media take place?

A)At least one level of control media should be analyzed every 8 hours.
B)At least two levels of control media should be analyzed every day.
C)At least two levels of control media should be analyzed every 8 hours.
D)At least two levels of control media should be analyzed every hour.

Question 76

Before a sample of capillary blood is taken, what should you do to the site?
I)warmed to 42° C for 10 minutes
II)squeezed lightly until blanched
III)cleaned with an antiseptic solution

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

Question 77

The equipment necessary for capillary blood sampling includes all of the following except:

A)lancet
B)capillary tubes
C)1-ml syringe
D)warming pad

Question 78

How is the accuracy of a blood gas analyzer determined?

A)examining the repeatability of the analyzer's results
B)comparing the analyzer's measurements to known values
C)adjusting the offset (or balance) of the instrument
D)adjusting the gain (or slope) of the instrument

Question 79

A blood gas analyzer measures all of the following except:

A)HCO₃^-
B)PCO₂
C)PO₂
D)pH

Question 80

Factors contributing to imprecision (random) errors during blood gas analysis include all of the following except:

A)sample contamination
B)contaminated buffers
C)statistical probability
D)sample mishandling