Question 1

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.

Accepted Answer

Most galvanic fuel cells use a gold anode and a lead cathode. Unlike the Clark electrode, current flow across these poles is generated by the chemical reaction itself. Thus, unless accessories such as alarms are included, a galvanic cell needs no external power. Unfortunately, this means that galvanic cells respond more slowly than do Clark electrodes, sometimes taking as long as 60 sec.

Question 2

Which of the following should be monitored during the sampling of arterial blood?
1) Blood pressure proximal to puncture site
2) Presence of pulsatile blood return
3) Presence of air bubbles or clots in sample
4) Appearance of puncture site
A)1, 2, and 3 only
B)2, 3, and 4 only
C)1, 2, 3, and 4
D)2 and 3 only

Accepted Answer

B

Question 3

Purposes of a needle-capping device include which of the following?
1) To isolate the sample from air exposure
2) To help prevent needlestick injuries
3) To hold the excess anticoagulant
A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Accepted Answer

Needle-capping devices serve two main purposes: to isolate a blood sample from air exposure and to help prevent needlestick injuries. They are not intended to hold excess anticoagulant, so option B is incorrect, and option C is incorrect as well. Therefore, the correct answer is A.

Question 4

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.

Accepted Answer

If a capping safety device is not provided, the clinician should use the single-handed "scoop" method to cap the needle before removing it and plugging the syringe.

Question 5

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

Accepted Answer

To avoid this problem during continuous use in humidified circuits, the clinician should place the analyzer sensor proximal to any humidification device.

Question 6

Clinical indications for arterial blood analysis include which of the following?
1) Sudden, unexplained dyspnea
2) Cardiopulmonary resuscitation
3) Changes in ventilator settings
4) Chest pain
A)1 and 3 only
B)2 and 4 only
C)1, 2, and 4 only
D)1, 2, and 3 only

Accepted Answer

Arterial blood analysis is necessary in cases of sudden unexplained dyspnea, changes in ventilator settings, and cardiopulmonary resuscitation in order to assess the patient's oxygenation and acid-base status. Chest pain alone is not a sufficient clinical indication for arterial blood analysis.

Question 7

How does the Clark polarographic O₂ electrode function? A) It measures the magnetic properties of O₂ versus N_2. B) It measures the electrical potential across a Wheatstone bridge. C) It uses O₂ to produce a reduction-oxidation reaction. D) It measures the comparative cooling effect on a heated wire.

Accepted Answer

This system typically consists of a platinum cathode and a silver-silver chloride anode . Oxygen molecules diffuse through the sensor membrane into the electrolyte, where a polarizing voltage causes electron flow between the anode and cathode. While silver is oxidized at the anode, the flow of electrons reduces oxygen (and water) to hydroxyl ions (OHF1F1F1S1^F1F1F10) at the cathode. The more O₂ molecules that are reduced, the greater is the electron flow across the poles (current). The resulting change in current is proportional to the PO₂, with its value displayed on a galvanometer, calibrated in percent oxygen.

Question 8

Which of the following are true about invasive versus noninvasive monitoring?
1. Invasive procedures require insertion of a device into the body.
2. Laboratory analysis of gas exchange is usually noninvasive in nature.
3. Physiologic monitoring can be either invasive or noninvasive.
4. Invasive procedures provide more accurate data but carry greater risks.
A)2 and 4 only
B)1, 3, and 4 only
C)2 only
D)1, 2, 3, and 4

Accepted Answer

Option 1 is true as invasive procedures do require insertion of a device into the body. Option 2 is also correct as laboratory analysis of gas exchange can be done through noninvasive techniques such as blood tests or capnography. Option 3 is true as physiologic monitoring can be either invasive or noninvasive. Option 4 is also correct as invasive procedures provide more accurate data but also carry greater risks due to their invasive nature. Hence, the correct option is B - 1, 3, and 4 only.

Question 9

Which of the following sites are used for arterial blood sampling by percutaneous needle puncture?
1) Femoral
2) Radial
3) Brachial
4) Carotid
A)2 and 3 only
B)1 and 4 only
C)1, 2, and 3 only
D)1, 2, 3, and 4

Accepted Answer

1, 2, and 3 (Femoral, Radial, Brachial) are commonly used sites for arterial blood sampling due to their accessibility and the relatively low risk of complications. The Carotid artery is generally avoided for percutaneous needle puncture due to the higher risk of complications.

Question 10

While checking a polarographic (Clark) electrode, 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.

Accepted Answer

Because a low battery condition is so common with Clark electrode systems, the first step in troubleshooting is to replace the batteries.

Question 11

Precautions and/or possible complications of arterial puncture include which of the following?
1) Arteriospasm
2) Embolization
3) Infection
4) Hemorrhage
A)1, 2, and 3 only
B)2 and 3 only
C)2 and 4 only
D)1, 2, 3, and 4

Accepted Answer

Arterial puncture carries the risk of arteriospasm, embolization, infection, and hemorrhage. Arteriospasm may result from stimulating the smooth muscle layer and can make it difficult to sample the blood. Embolization is the release of particulate matter into the bloodstream, leading to obstruction of distal vessels. Infection may occur if aseptic technique is not followed during the procedure, and hemorrhage may result from the puncture itself or the manipulation of the artery during the procedure. Therefore all the given options (1, 2, 3, and 4) are the precautions and/or possible complications of arterial puncture.

Question 12

Under ideal conditions, electrochemical oxygen (O₂) analyzers have approximately what degree of accuracy? A) 1% B) 2% C) 3% D) 4%

Accepted Answer

There are two common types of electrochemical oxygen analyzers: (1) the polarographic (Clark) electrode and (2) the galvanic fuel cell. Under ideal conditions of temperature, pressure, and relative humidity, both types are accurate to within ±2% of the actual concentration.

Question 13

Why is the radial artery the preferred site for arterial blood sampling?
1) It is near the surface and easy to palpate and stabilize.
2) The ulnar artery normally provides good collateral circulation.
3) The radial artery is not near any large veins.
4) It is the largest artery located in the upper extremities.
A)1 and 4 only
B)3 only
C)2 and 4 only
D)1, 2, and 3 only

Accepted Answer

The radial artery is preferred for arterial blood sampling because it is easily accessible and palpable, has good collateral circulation from the ulnar artery, and is not located near large veins, reducing the risk of venous puncture. The radial artery is not the largest artery in the upper extremities; that distinction belongs to the brachial artery.

Question 14

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.

Accepted Answer

If the analyzer still does not calibrate on fresh batteries, the problem is probably a depleted sensor. With most analyzers, a depleted sensor must be replaced (some Clark electrodes can be recharged).

Question 15

Which of the following are reasons for finding an alternative site for arterial puncture?
1) Failed Allen test
2) History of peripheral vascular disease
3) Anticoagulation therapy
4) Presence of a surgical shunt
A)1, 2, and 4 only
B)2 and 4 only
C)1, 2, and 3 only
D)1, 3, and 4

Accepted Answer

• Failed Allen test indicates inadequate collateral circulation to the hand, making arterial puncture more risky.
• History of peripheral vascular disease indicates compromised blood flow to the limbs, increasing the risk of complications during arterial puncture.
• Presence of a surgical shunt indicates that the desired artery is already compromised and not suitable for puncture. 
• Anticoagulation therapy increases the risk of bleeding complications during arterial puncture, but does not necessarily require an alternative site.

Question 16

Which of the following patient parameters does not need to be assessed as part of arterial blood sampling?
A) Blood pressure
B) Temperature
C) Position or activity level
D) Clinical appearance

Accepted Answer

To guide practitioners in providing quality care, the American Association for Respiratory Care (AARC) has published Clinical Practice Guideline: Sampling for Arterial Blood Gas Analysis. Modified excerpts from the AARC guideline appear on p. 373.

Question 17

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

Accepted Answer

If you suspect that pain or anxiety during the procedure may have altered the results (most typically causing hyperventilation), consider using a local anesthetic for subsequent sampling attempts.

Question 18

What chart information should be checked before performing artery puncture? 1) Patient's primary diagnosis and history 2) Presence of bleeding disorders or blood-borne infections 3) Anticoagulant or thrombolytic drug prescriptions 4) Respiratory care orders (e.g., O₂ therapy) A)1, 2, and 3 only B)2 and 3 only C)2, 3, and 4 only D)1, 2, 3, and 4

Accepted Answer

All listed information is important to check before performing an artery puncture to ensure patient safety and proper procedure.

Question 19

After obtaining an arterial blood sample, what should you do?
1) Apply pressure to the puncture site until bleeding stops.
2) Place the sample in a transport container with ice slush.
3) Check to see if the patient is getting anticoagulant therapy.
4) Mix the sample by rolling and inverting the syringe.
A)1 and 2 only
B)1, 2, and 4 only
C)3 and 4 only
D)1, 2, 3, and 4

Accepted Answer

The answer of After obtaining an arterial blood sample, what...

Question 20

Which of the following indicates venous admixture during arterial puncture?
1) Need to use syringe suction.
2) Dark-colored blood.
3) Small sample volumes.
A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Accepted Answer

The answer of Which of the following indicates venous admixture...

Quiz 19: Analysis and Monitoring of Gas Exchange

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

Which of the following should be monitored during the sampling of arterial blood? 1) Blood pressure proximal to puncture site 2) Presence of pulsatile blood return 3) Presence of air bubbles or clots in sample 4) Appearance of puncture site

Purposes of a needle-capping device include which of the following? 1) To isolate the sample from air exposure 2) To help prevent needlestick injuries 3) To hold the excess anticoagulant

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

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?

Clinical indications for arterial blood analysis include which of the following? 1) Sudden, unexplained dyspnea 2) Cardiopulmonary resuscitation 3) Changes in ventilator settings 4) Chest pain

How does the Clark polarographic O2 electrode function?

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

While checking a polarographic (Clark) electrode, 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?

Precautions and/or possible complications of arterial puncture include which of the following? 1) Arteriospasm 2) Embolization 3) Infection 4) Hemorrhage

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

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?

Which of the following are reasons for finding an alternative site for arterial puncture? 1) Failed Allen test 2) History of peripheral vascular disease 3) Anticoagulation therapy 4) Presence of a surgical shunt

Which of the following patient parameters does not need to be assessed as part of arterial blood sampling?

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

What chart information should be checked before performing artery puncture? 1) Patient's primary diagnosis and history 2) Presence of bleeding disorders or blood-borne infections 3) Anticoagulant or thrombolytic drug prescriptions 4) Respiratory care orders (e.g., O2 therapy)

Which of the following indicates venous admixture during arterial puncture? 1) Need to use syringe suction. 2) Dark-colored blood. 3) Small sample volumes.

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

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?

How does the Clark polarographic O₂ electrode function?

While checking a polarographic (Clark) electrode, 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?

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

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?

What chart information should be checked before performing artery puncture? 1) Patient's primary diagnosis and history 2) Presence of bleeding disorders or blood-borne infections 3) Anticoagulant or thrombolytic drug prescriptions 4) Respiratory care orders (e.g., O₂ therapy)