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WorksheetsFundamentals Final Worksheet — Oxygen and Blood Gas Analysis
Total questions: 95
Worksheet time: 48mins
If a patient presents with PaO2 of 65 , what would you classify this as?
Mild hypoxemia
Moderate hypoxemia
Severe hypoxemia
Normal oxygenation
If an arterial blood gas analyzer reports a PaO2 of 45 , what would you consider this?
Mild hypoxemia
Moderate hypoxemia
Severe hypoxemia
Normal oxygenation
Which PaO2 level is considered severe hypoxemia?
Less than 40
40 to 59
60 to 79
80 or higher
If a patient’s oxygen level reads above 100 , what is this termed and what is the best plan of action?
Hyperoxemia; gradually wean oxygen delivery to lower levels
Hyperoxemia; immediately discontinue all oxygen
Hypoxemia; increase oxygen support
Normoxemia; maintain current oxygen settings
Select the oxygen analyzers most commonly used by respiratory therapists.
Clark electrode
Galvanic fuel cell
Paramagnetic analyzer
Infrared spectrophotometer
You need blood to be analyzed as quickly as possible and have access to a Clark electrode and a galvanic fuel cell. Which analyzer provides the quickest response time?
Clark electrode
Galvanic fuel cell
Paramagnetic analyzer
Pulse oximeter
A Clark electrode is not working properly. What is the first action you should take to try to fix it?
Check or replace the batteries
Change the sensor and recalibrate
Send the device for repair or replace it
Increase the patient’s oxygen setting
A galvanic fuel cell does not require batteries because it uses a chemical reaction to power itself. If it did have batteries, why would they be used?
To power the chemical reaction
To run an internal sample pump
To power alarms that indicate low oxygen
To heat the sensor element
How would you properly recalibrate an oxygen analyzer?
Expose to 21% oxygen (room air), then to 100% oxygen
Expose first to 100% oxygen, then to 21% oxygen
Expose only to room air
Expose only to pure nitrogen
When using an oxygen analyzer, the patient is on 70% oxygen and the analyzer reads 67% . Would this be considered accurate?
Yes, it is within the ± 2% tolerance
No, it is outside the ± 2% tolerance
When using an oxygen analyzer, the patient is on 70% oxygen and the analyzer reads 72% . Would this be considered accurate?
Yes, it is within the ± 2% tolerance
No, it is outside the ± 2% tolerance
What is considered the gold standard for evaluating and identifying gas exchange and acid–base balance?
Arterial blood gas (ABG)
Pulse oximetry
Capnography
Transcutaneous oxygen monitoring
If you are not able to obtain a blood gas from an artery, where else might you be able to obtain it?
Capillary sample
Venous sample
Oral swab
Exhaled breath condensate
Where is the best place to stick when collecting an arterial blood gas?
Radial artery
Ulnar artery
Brachial artery
Femoral artery
Why is the radial artery considered the best place to obtain a blood gas? Select all that apply.
It is closer to the surface, bigger, and easier to palpate
It is away from veins and nerves
The ulnar artery provides good collateral circulation backup
It is deep and hard to palpate
It is usually near a surgical shunt
Where is an arterial blood usually taken in emergent situations?
Radial artery
Ulnar artery
Femoral artery
Brachial artery
What does an ABG determine in a patient? Select all that apply.
How well the patient is ventilating
How well the patient is oxygenating
The patient’s acid–base balance
The patient’s hematocrit level
When taking an ABG, what value is used to determine the patient’s acid–base balance?
SaO2
PaCO2
pH
PaO2
When taking an ABG, what value is used to determine how well the patient is ventilating?
SaO2
PaCO2
pH
PaO2
When taking an ABG, what value is used to determine how well the patient is oxygenating?
SaO2
PaCO2
pH
PaO2
What would be considered contraindications when taking an arterial blood gas? Select all that apply.
Negative Allen test
Surgical shunt
Positive Allen test
Patient consent obtained
What can cause a hematoma or hemorrhage? Select all that apply.
Use of anticoagulants (e.g., heparin)
Constant flow of bleeding from a damaged blood vessel
Inadequate collateral circulation
Tight tourniquet alone
When obtaining an ABG, how much blood should you collect for the sample?
0.5 mL to 1 mL
2 mL to 3 mL
5 mL
10 mL
In some situations it is okay to recap a used needle.
True
False
You go to collect an ABG sample and get dark, slow-moving blood in the syringe. What has most likely happened?
This is normal; finish collecting the sample
The patient is on a blood thinner so this is normal
You are in a vein, not an artery
The patient has a high heart rate
If you run an ABG sample that has air in it through an analyzer, what result can you expect?
Low pH
High PaCO2
Cannot predict results
High PaO2
A healthy patient just ran up the stairs and is out of breath. How long should you wait before taking their ABG?
1 minute
5 minutes
15 minutes
30 minutes
A COPD patient just ran up the stairs and is out of breath. How long should you wait before taking their ABG?
5 to 10 minutes
10 to 15 minutes
20 to 30 minutes
45 to 60 minutes
If an ABG is not placed on ice and takes a long time to get to the lab, what result would you expect?
Increased PaCO2
Decreased PaCO2
Increased PaO2
No change in blood gases
What is point of care for ABGs and what can it help reduce? Select all that apply.
A bedside blood analyzer that allows testing as soon as the sample is collected
Helps reduce turnaround time
Helps reduce labeling issues
Increases transport time to the lab
Eliminates the need for trained staff
On a pulse oximeter the alarm should be set to go off if the pulse oximeter reads below ____%.
85%
88%
90%
92%
Do you need an order for oxygen? Why or why not?
No, oxygen is considered basic comfort care
Yes, because oxygen is considered a drug and medical gas
No, oxygen can be given without physician oversight
Yes, but only for patients in the ICU
Do you need an order to do an ABG?
Yes, an order is required
No, it is part of routine vital signs
Only if the patient is on a ventilator
An order is optional if the patient consents
Which description correctly distinguishes PAO2 from PaO2?
PAO2 is partial pressure of oxygen in the alveoli; PaO2 is partial pressure of oxygen in the arteries
PAO2 is oxygen saturation in the arteries; PaO2 is oxygen saturation in the alveoli
PAO2 and PaO2 are the same measurement taken at different times
PAO2 is partial pressure of oxygen in venous blood; PaO2 is partial pressure in capillaries
Which thresholds indicate hypoxemia?
PaO2 less than 60 mm Hg
SaO2 less than 90%
PaO2 greater than 80 mm Hg
SaO2 greater than 94%
If you administer too much oxygen to a neonate, what could this cause?
Bronchiolitis
Retinopathy of prematurity (ROP)
Pneumothorax
Neonatal jaundice
What kind of room would be more at risk for a fire hazard?
Operating room with high FiO2 present
General medical ward
Outdoor triage area
Radiology waiting room
What is the main factor that changes FiO2 for patients using a nasal cannula?
Cannula color
How the patient is breathing (e.g., mouth breathing lowers FiO2)
Patient’s weight
Age of the patient
A high flow nasal cannula is more fixed than a low flow nasal cannula.
True
False
Give an example of devices corresponding to high-flow, low-flow, and reservoir oxygen transport systems.
High-flow nasal cannula
Nasal cannula (low-flow)
Simple mask (reservoir)
Noninvasive ventilator circuit
How do you check the specific FiO2 output?
Use an oxygen analyzer
Use a Clark electrode (galvanic fuel cell)
Estimate from the flowmeter alone
Visual inspection of patient color
If a patient is on sedation while using a nasal cannula, would the patient breathe higher or lower FiO2, and why?
Lower FiO2 because slower breathing pulls in more room air
Higher FiO2 because slower breathing entrains less room air
No change in FiO2 because sedation does not affect entrainment
Lower FiO2 because sedation increases respiratory rate
What is the FiO2 range used for nasal cannulas?
10% – 20%
24% – 44%
40% – 60%
60% – 80%
What is the appropriate liter flow range for patients using a nasal cannula?
0.5 L to 2 L
1 L to 6 L
6 L to 10 L
10 L to 15 L
If your patient is on 5 L nasal cannula and is experiencing dried upper airways, what action might the RT take?
Decrease the flow to 2 L
Add a humidifier to the oxygen delivery
Switch to room air
Apply a nonrebreather mask
If your patient is on 4 L nasal cannula, what can you approximate the FiO2 to be close to?
28%
32%
36%
40%
If your patient is on humidified nasal cannula and the humidifier is making a loud whistling noise, what problem could you expect?
Humidifier chamber is empty
Oxygen line is pinched, triggering the pop-off valve
Cannula prongs are reversed
Flowmeter is set too low for humidification
What is the liter flow range for a simple mask?
1 L to 4 L
5 L to 10 L
10 L to 15 L
15 L to 20 L
What must a simple mask’s minimum flow be and why?
At least 2 L to prevent dryness
At least 5 L to flush out CO2 and prevent rebreathing
At least 8 L to reach 100% FiO2
No minimum; any flow is acceptable
How long does it take for a patient with healthy lungs to achieve a normal steady state after being out of breath, and how long does it take a patient with lung disease or a chronic lung problem to achieve steady state?
Healthy lungs: about 5 minutes; lung disease: 20 – 30 minutes
Healthy lungs: about 1 minute; lung disease: 5 minutes
Healthy lungs: about 10 minutes; lung disease: 60 minutes
Healthy lungs: about 30 minutes; lung disease: 2 hours
How many valves are on a partial rebreather?
None
One
Two
Three
How many valves are on a nonrebreather?
None
One
Two
Three
What percent of FiO2 is the patient getting with a nonrebreather?
60%
80%
100%
Variable depending on breathing pattern
If the bag on a nonrebreather or partial rebreather is not inflated and is small and crumbled, what action might the RT take?
Remove the mask and use room air
Turn up the oxygen flow until the bag is inflated (a little deflation on inspiration is normal)
Decrease the oxygen flow to reduce noise
Switch immediately to mechanical ventilation
What O2 delivery device is used to achieve specific FiO2 values?
Venturi mask
Nasal cannula
Simple face mask
Nonrebreather mask
When using a venturi mask, if one of the ports becomes blocked, what happens to the FiO2?
It increases because less air dilutes the oxygen
It decreases because more room air enters
It remains the same
It varies randomly without trend
What strategy do you use to calculate the Air to Oxygen ratio?
Magic box
Alveolar gas equation
Boyle’s law
Haldane transformation
Using the magic box method, what is the Air to O2 ratio for an FiO2 of 40%?
3.2:1
2:1
1.7:1
4:1
If your patient is on 50% FiO2 and 4 L/min flow, what is the total flow of this patient based on the worksheet’s calculation?
0.67 L/min
6.7 L/min
10.8 L/min
14.0 L/min
What is the oxyhood used for and what benefit does it provide?
Deliver controlled oxygen to infants without a face mask
Provide high-flow oxygen to adults with COPD
Transport ventilated patients during MRI
Administer anesthesia gases in the operating room
Which reasons indicate a need for hyperbaric oxygen therapy? Select all that apply.
Diving accident
Reduction of gas bubbles
Wound care
Ear trauma from pressure changes
Asthma exacerbation
What color is an O2 cylinder?
Green
Yellow
Blue
Brown
What color is a medical air cylinder?
Yellow
Green
Black
Brown
What is the E tank factor?
0.28
0.16
1.7
3.14
What is the H and K tank factor?
3.14
0.28
1.0
2.5
How can you tell how much gas is left in a tank?
Read the pressure gauge
Tap the tank and listen
Weigh the tank
Check the regulator size
How do you calculate how much time is left before a tank is empty?
Tank factor × pressure gauge ÷ liter flow
Pressure gauge ÷ tank factor × liter flow
Liter flow × pressure gauge ÷ tank factor
Tank factor + pressure gauge + liter flow
For an Oxygen E tank at 1000 psi with a flow of 3 L/min, how long until the tank is empty?
93 minutes
47 minutes
155 minutes
31 minutes
For an Oxygen H tank at 2000 psi with a flow of 5 L/min, when will the tank need to be replaced with a full one?
1,256 minutes
620 minutes
93 minutes
21 minutes
How pure must O2 tanks be before they can be used under FDA requirements?
99% pure oxygen
95% pure oxygen
90% pure oxygen
100% pure oxygen
What color are helium tanks?
Brown
Green
Yellow
Black
What color are Heliox tanks?
Brown and green
Green and yellow
Blue and white
Black and silver
Why would a patient need heliox to be used?
To lower gas density and improve flow past upper airway obstruction
To increase anesthetic potency during surgery
To humidify airways better than oxygen
To reduce alveolar dead space in emphysema
What are appropriate precautions for storing gas tanks? Select all that apply.
Post no‑smoking signs in the area
Secure and chain tanks so they do not fall
Allow the fill to vary within about 10% of the labeled amount
Store next to heat sources to prevent cooling
Lay tanks horizontally to save space
When getting a new gas tank, what should the RT do before use?
Crack the valve briefly to clear debris
Fully open the valve immediately
Purge the line by turning on the regulator to maximum
Shake the tank to settle contents
What are zone valves used for in hospitals?
Stopping gas flow to specific areas without shutting down the entire facility
Increasing line pressure for high‑flow devices
Mixing medical gases centrally
Measuring wall‑outlet pressures
What is the minimum working pressure for gas that comes through hospital walls?
50 psi
20 psi
80 psi
100 psi
What is the most important factor of large volume jet nebulizers?
Temperature (cooled or heated)
Particle charge
Tank color
Patient age
For a patient with upper airway swelling on a large volume jet nebulizer, which temperature setting is appropriate?
Cooled aerosol
Heated aerosol
Room‑temperature dry gas
Humidified oxygen without aerosol
If a patient with a bypassed upper airway is on a large-volume jet nebulizer, should the nebulizer be cooled or heated?
Cooled
Heated
For a patient using a T-piece trach collar, should the oxygen be heated or cooled?
Heated
Cooled
What is the most important factor for humidification?
Temperature
Surface area
Time of contact
Thermal mass
Which factors affect humidification? Select all that apply.
Temperature
Surface area
Time of contact
Thermal mass
Which are humidification problems? Select all that apply.
Condensation buildup
Improper conditioning of gas
Cross contamination
Increased humidity improves airway clearance
What is the tank factor for an 80:20 Heliox tank?
1.4
1.6
1.8
2.0
What is the tank factor for a 70:30 Heliox tank?
1.4
1.6
1.8
2.0
How do you calculate the actual flow on a Heliox tank?
Liter flow × tank factor
Liter flow ÷ tank factor
Tank size × liter flow
Tank factor ÷ liter flow
A patient is on an 80:20 Heliox tank at a flow of 3 L/min. What is the actual flow?
3.0 L/min
4.2 L/min
5.4 L/min
6.0 L/min
A patient is on 70:30 Heliox with a liter flow of 2 L/min. What is the actual flow?
2.6 L/min
3.2 L/min
3.6 L/min
4.0 L/min
Which formula converts Fahrenheit to Celsius?
(F − 32) ÷ 1.8
(F × 1.8) + 32
(F ÷ 1.8) + 32
(F − 32) × 1.8
Which formula converts Celsius to Fahrenheit?
(C − 32) ÷ 1.8
(C × 1.8) + 32
(C ÷ 1.8) + 32
(C × 1.8) − 32
What is 50 degrees Fahrenheit in Celsius?
10 degrees Celsius
20 degrees Celsius
30 degrees Celsius
5 degrees Celsius
What is 20 degrees Celsius in Fahrenheit?
60 degrees Fahrenheit
64 degrees Fahrenheit
68 degrees Fahrenheit
72 degrees Fahrenheit
What is capillary action?
Movement of fluid up against gravity in narrow tubes
Downward flow of fluid due to gravity
Mixing of two fluids of different densities
Evaporation of fluid from an open surface
Which are examples of capillary action? Select all that apply.
Capillary sticks
Aerosols in nebulizers where fluid in the cup moves up into the air stream
Condensation forming on the outside of a tank
Bulk flow through large-diameter tubing
