1. Medical Gas Therapy

2. Goals of O2 Therapy Relieve hypoxemia Decrease WOB
Pneumonia, V/Q mismatch
Decrease WOB
Asthma, COPD
Decrease myocardial work
MI, pulmonary edema

3. Effects of Hypoxemia Peripheral vasodilation
Patient feels warm
Pulmonary vasoconstriction
Shunting, increased PVR
Tachycardia
Primary indication of hypoxemia

4. B.Remove the cannula and verify the flow C.Troubleshoot the equipment
A 56 year old female patient is receiving oxygen at 1.5 L/min. via a pulsed-dose oxygen delivery system attached to a reservoir cannula. As you are doing your oxygen rounds, the patient complains of severe shortness of breath and states "she is not getting enough air". What would be your first immediate response at this time?
A.Attach the patient’s reservoir cannula to a thorpe tube flowmeter at 1.5 L/min.
B.Remove the cannula and verify the flow
C.Troubleshoot the equipment
D.Increase the liter flow to 2 L/min.
Take care of the patient first!
A Will give the patient O2 immediately (then check what else may be wrong)
B Focusing on the equipment not the patient, does not help the pt
C Same as b
D May or may not help, because you do not know what is going on

5. A.polarographic electrode analyzer B.precision geisler tube analyzer
The best way to check the accuracy of an air/oxygen proportioner is by using:
A.polarographic electrode analyzer
B.precision geisler tube analyzer
C.infrared absorption analyzer
D.teflon membrane analyzer
= blender
A = O2 analyzer polorographic (has two o’s = O2)
B Nitrogen analyzer could work but a is better
C CO2 or CO analyzer
D Blood gas PaCo2 analyzer

6. B. Recommend changing to an F I O 2 of 1.0.
A patient with a laryngeal tumor is presently receiving 80/20% helium-oxygen by a nonrebreathing mask at 5 L/min. The patient is alert, but appears agitated. Vital signs indicate a pulse of 131/min, respirations at 30/min, and a blood pressure of 140/90 mm Hg. Which of the following is the most appropriate action to take?
A. Initiate sedation.
B. Recommend changing to an F I O 2 of 1.0.
C. Increase the gas flow to the mask.
D. Administer racemic epinephrine.
EXPLANATIONS:
(h) A. Initiating sedation could further reduce the patient's ability to provide adequate ventilation.
(u) B. Increasing the F I O 2 would improve oxygenation, but would not help with carbon dioxide elimination from the lungs.
(c) C. Higher flows of helium/oxygen, undiluted by air entrainment, will ensure consistent administration of the 80/20 mixture and improve ventilation past the stricture caused by the laryngeal tumor.
(u) D. Administering racemic epinephrine will have no effect on the size of the laryngeal tumor.

7. ALL Equipment! Know When to use it. How to fit it.
Increase flow is the most common troubleshooting answer on the exam.

8. I. Air/oxygen proportioner II. Venturi mask III. Oxygen analyzer
The physician has requested that you administer 80% helium and 20% oxygen mixture to a patient. Which of the following equipment would you need to administer the therapy?
I.    Air/oxygen proportioner
II.    Venturi mask
III.    Oxygen analyzer
IV.    Non-rebreather mask
A.IV only
B.I and III only
C.II only
D.I, III and IV only
1Comes already mixed, so don’t need this
2Entrains air and will mess up the mixtiue
3No need, it’s already mixed
4This is all you need to provide 100% source gas. But must stay partially inflated at all times.

9. A.Tape the Venturi mask to the patient’s face B.Restrain the patient
A patient is receiving oxygen via a Venturi mask at an FIO2 of The nurse is complaining that the patient keeps removing the Venturi mask from his face. You would do which of the following at this time?
A.Tape the Venturi mask to the patient’s face
B.Restrain the patient
C.Switch to a nasal cannula at 6 L/min.
D.Intubate the patient orally
Atempting, but not the best answer, would be inappropriate
BTempting, but not good
CThis would solve the problem (about the same FiO2 4%/L + RA = 45%)
DMay keep them from complaining but not the best way to solve the problem

10. What is the least likely problem to watch for in a severe COPD patient receiving supplemental O2?
Pulmonary edema from O2 toxicity
Hypoventilation
Retinopathy of prematurity (ROP)
Hyperventilation

11. The recommended effective dose for Nitric Oxide Therapy is:
0.5 – 1.5 ppm
2 – 20 ppm
80 – 150 ppm
400 – 600 ppm

12. A patient is receiving 100% oxygen via an aerosol mask at 10 Lpm
A patient is receiving 100% oxygen via an aerosol mask at 10 Lpm. Each time the patient inhales the aerosol mist disappears. The therapist has attempted to increase the flowrate without success. Which of the following should the therapist recommend?
Switch to a tandem set-up
Change to a non-rebreather
Decrease the FiO2 to 75%
Change to assisted ventilation with 100% oxygen

13. What is the approximate total flow that would be delivered from a 40% air-entrainment mask receiving 12 L/min of oxygen?
A. 12 L/min
B. 48 L/min
C. 52 L/min
D. 72 L/min
EXPLANATIONS:
(u) A. See B for correct calculation.
(c) B. A 40% air-entrainment mask entrains air at a ratio of (3)air:(1)O 2 . Let x = O 2 flow in L/min 3x = air entrained 3x + x = total flow 3(12) + 12 = total flow = 48 L/min.
(u) C. See B for correct calculation.
(u) D. See B for correct calculation.

14. Air: oxygen entrainment ratios 28% 35%
Ratio = 10:1 Factor = 11
35%
Ratio = 4.3:1 Factor = 5.3
Just flip it around!
40%
Ratio = 3:1 Factor = 4
60%
Ratio = 1:1 Factor = 2

15. A patient has just been admitted through the emergency department with suspected CO poisoning. The physician wants her to receive the highest possible O2 percentage. What would you recommend?
Continuous positive airway pressure mask at 5 cmH2O and 40% O2
Simple mask at 6 L/min flow
Face tent at 8 L/min flow
Nonrebreather mask with enough flow to keep the reservoir bag at least two-thirds full

16. B. cause oxygen toxicity. C. trigger retinopathy.
A patient with chronic hypercapnia is to receive oxygen at home by nasal cannula at 2 L/min. The respiratory therapist should advise the patient to ensure the oxygen flow does not exceed 2 L/min because excessive oxygenation may
A. dry secretions.
B. cause oxygen toxicity.
C. trigger retinopathy.
D. depress breathing.
EXPLANATIONS:
(u) A. Exposure to high levels of oxygen is not known to dry secretions.
(u) B. The incidence of oxygen toxicity is increased when a patient has extended exposure to F I O 2 levels = It is very unlikely that a nasal cannula is able to deliver an F I O 2 = 0.60.
(u) C. Retinopathy of prematurity is a complication of elevated PaO 2 levels and has the highest incidence in neonates weighing < 1 kg.
(c) D. Patients with chronic hypercapnia breathe in response to hypoxic stimulation of aortic and carotid receptors. Excessive supplemental oxygen may suppress the hypoxic ventilatory drive and result in hypoventilation.

17. You are making general rounds in the hospital when you find a patient whose reservoir tuning has fallen off his 40% Brigg’s adapter. This would result in which of the following?
Increased inspired O2
Increased inspired CO2
Decreased inspired CO2
Decreased inspired O2

18. A. increase the oxygen liter flow by 5 L/min.
A patient is receiving oxygen by a nonrebreathing mask. The reservoir bag collapses during inspiration. The respiratory therapist should
A. increase the oxygen liter flow by 5 L/min.
B. adjust the flow until the reservoir bag remains partially inflated at end-inspiration.
C. remove leaflet valves from exhalation ports.
D. remove the one-way valve between the reservoir bag and the mask.
EXPLANATIONS:
(a) A. Increasing the flow may solve the problem; however, further assessment is required since 5 L/min may still not be sufficient.
(c) B. The flow should be increased to ensure adequate volume in the reservoir bag throughout each breath.
(h) C. Removing the leaflet valves will decrease the concentration of oxygen due to air dilution and may inappropriately lower the F I O 2 .
(h) D. Removing the one-way valve changes the mask to a partial rebreathing mask and may inappropriately lower the F I O 2 .

19. The risks of O2 therapy include all of the following EXCEPT:
Pulmonary O2 toxicity
Denitrogen absorption atelectasis
O2 induced hyperventilation
ROP

20. A. nasal cannula placed on patient, HR=96, SpO 2 =92%, RR=22
A respiratory therapist has initiated oxygen therapy with a nasal cannula. In addition to a signature and credentials, which of the following is the best example of appropriate documentation?
A. nasal cannula placed on patient, HR=96, SpO 2 =92%, RR=22
B. 12/6/03, 2 L/min oxygen placed on patient at 0830
C. 0830, nasal cannula at 2 L/min, temp=101, HR=96, RR=22, BP=150/80
D. 12/6/03, 0830, nasal cannula started at 2 L/min, SpO 2 =92%, RR=22, HR=96
EXPLANATIONS:
(u) A. See D for explanation.
(u) B. See D for explanation.
(u) C. See D for explanation.
(c) D. This includes all appropriate information: date, time, mode, liter flow, and the patient's response to therapy.

21. A. the flow is set too high.
An air-entrainment mask will deliver an F I O 2 higher than intended if
A. the flow is set too high.
B. nebulized water is being added through the air-entrainment ports.
C. corrugated tubing was added between the air-entrainment adapter and mask.
D. the air-entrainment ports have been blocked.
EXPLANATIONS:
(u) A. If the flow is set higher than recommended, it will entrain more room air and still maintain the same F I O 2 . It will not deliver a higher F I O 2 than intended.
(u) B. Adding nebulized water through the air-entrainment ports is not routinely performed. The F I O 2 will not increase.
(u) C. Adding tubing between the air-entrainment adapter and the mask will not cause the mask to entrain less room air and deliver a higher F I O 2 than expected.
(c) D. If the air-entrainment ports have been blocked, room air cannot be entrained and the patient will receive a higher F I O 2 than expected.

22. Plugged capillary line Dry analyzer chamber
You are working with an intubated patient who is mechanically ventilated. The O2 analyzer is a galvanic fuel-cell type. Every time the patient’s airway pressure fluctuates during a mechanical breath, the O2 percentage goes up and then down. This could be caused by:
Plugged capillary line
Dry analyzer chamber
Variable pressure against analyzer probe
Exhausted supply of chemical reactant
Pressure sensitive,
Use a polarographic analyzer

23. A. air-entrainment mask B. nasal cannula C. nonrebreathing mask
Which of the following oxygen administration devices is capable of meeting and/or exceeding a patient's inspiratory flow?
A. air-entrainment mask
B. nasal cannula
C. nonrebreathing mask
D. reservoir cannula
EXPLANATIONS:
(c) A. The entrainment of room air can result in total flow equal to, or exceeding, patient peak inspiratory flow and tidal volume.
(u) B. A nasal cannula is generally not used at flows greater than 6 L/min. Average patient peak inspiratory flow is 35 L/min; therefore, tidal volume requirements cannot be met by nasal cannula flow alone.
(u) C. A nonrebreathing mask may deliver a high flow, but it cannot be determined if total flow is adequate to meet the patient's needs.
(u) D. A reservoir cannula cannot deliver a flow high enough to meet a patient's inspiratory needs.

24. A. air-entrainment mask B. oxygen hood C. infant nasal cannula
A physician orders an F I O 2 of 0.40 for a premature infant in an incubator. Which of the following delivery devices should the respiratory therapist select?
A. air-entrainment mask
B. oxygen hood
C. infant nasal cannula
D. simple mask
EXPLANATIONS:
(h) A. The F I O 2 delivered with an air-entrainment mask will be adequate, but this is not the appropriate delivery system for an infant. The flow is too high and will adversely affect body temperature.
(c) B. The oxygen hood will deliver a precise F I O 2 . It will allow maintenance of a neutral thermal environment and allow access for nursing care.
(u) C. The F I O 2 of an infant nasal cannula is variable, based on minute ventilation and liter flow.
(h) D. The F I O 2 delivered with a simple mask is variable and will exceed 40% in a premature infant.

25. Your patient is wearing a partial-rebreathing mask
Your patient is wearing a partial-rebreathing mask. The reservoir bag almost totally collapses during her inspiration. You would do which of the following?
Tell the patient to breath more slowly
Put a nasal cannula on the patient
Tell the patient to breath more rapidly
Increase the O2 flow

26. A patient is receiving 80%/20% heliox using a standard oxygen flowmeter. Which of the following is the correction factor to determine the accurate flow?
A. 1.4
B. 1.6
C. 1.8
D. 2.4
EXPLANATIONS:
(u) A. See explanation C.
(u) B. See explanation C.
(c) C. The correction factor for 80% / 20% heliox is 1.8.
(u) D. See explanation C.

27. Heliox conversion factors: 80% He / 20% O2 70% He / 30% O2
1.8
70% He / 30% O2
1.6

28. What O2 delivery device would you recommend for a patient who has a variable respiratory rate, I:E ratio, and Vt?
Nasal cannula
Air-entrainment mask
Simple O2 mask
Face tent

29. A. Obtain a blood gas sample and notify the physician.
A patient with COPD is receiving oxygen, 2 L/min by nasal cannula, at home. The patient's SpO 2 is usually 90%. When visiting the patient, the respiratory therapist finds the oxygen set at 4 L/min, the patient lethargic, and his oxygen saturation is 95%. Which of the following should the therapist do immediately?
A. Obtain a blood gas sample and notify the physician.
B. Contact the physician and request hospital admission.
C. Change the oxygen flow to 2 L/min and observe the patient.
D. Discontinue oxygen until the patient's mental status improves.
EXPLANATIONS:
(h) A. Assuming an accurate SpO 2 , an arterial blood gas is unnecessary and would delay intervention, possibly leading to acute ventilatory failure.
(h) B. Physician notification is unnecessary and hospital admission may be harmful because it delays immediate care.
(c) C. This patient needs an adequate PaO 2 but not high enough to blunt the hypoxic drive.
(h) D. Discontinuing O 2 therapy would lead to hypoxemia.

30. The physician asks you which O2 delivery device would be best for a patient who needs about 75% O2. You would recommend which of the following?
Nonrebreathing mask
Face tent
Air-entrainment mask
Simple O2 mask

31. A. change oxygen analyzers. B. check the air inlet for an obstruction.
An 18-month-old infant is to receive 30% oxygen by mist tent. While performing a routine equipment check, the respiratory therapist notices the oxygen analyzer inside the tent reads 25%. After calibrating the oxygen analyzer, it still indicates 25%. The therapist should
A. change oxygen analyzers.
B. check the air inlet for an obstruction.
C. check the oxygen inlet for an obstruction.
D. add sterile water to the nebulizer reservoir.
EXPLANATIONS:
(u) A. Proper calibration indicates correct functioning of the analyzer. Replacement not indicated.
(u) B. Obstruction of the air inlet can only increase the F I O 2 .
(c) C. Obstruction of the oxygen inlet can decrease the F I O 2 .
(u) D. Adding water to the reservoir will not affect F I O 2 inside the tent.

32. A patient has a nasal cannula and needs to be transported on a stretcher. The E-size O2 cylinder will need to be laid flat under the stretcher. What flow meter would you recommend using?
Backpressure-compensated Thorp
Nonbackpressure-compensated Thorp
Bourdon
Backpressure-compensated kinetic

33. The respiratory therapist is calibrating several gas measurement devices in the ICU. Air should be used to zero calibrate which of the following?
A. capnograph
B. nitrogen analyzer
C. Clark electrode
D. oxygen analyzer
EXPLANATIONS:
(c) A. A capnograph uses air for zero point calibration because it contains no CO 2 .
(u) B. A nitrogen analyzer has an air calibration point of mm Hg (760 x 78%).
(u) C. A Clark electrode has an air calibration point of mm Hg (760 x 21%).
(u) D. An oxygen analyzer reads 21% (or mm Hg) in air.

34. Which of the following devices should be used to effectively deliver a 70% helium/30% oxygen mixture to a patient?
A. simple mask
B. oxygen hood
C. nasal cannula
D. nonrebreathing mask
EXPLANATIONS:
(u) A. A simple mask is not capable of delivering a reasonably accurate percentage and therapeutic amount of a helium/oxygen mixture.
(u) B. Large volume enclosures are unsatisfactory because helium tends to concentrate at the top of these devices.
(u) C. Because of dilution with ambient air, low-flow nasal devices are ineffective for delivering helium/oxygen mixtures.
(c) D. An appropriately fitted nonrebreathing mask does not permit air-entrainment and will maintain the helium gas concentration.

35. What is the duration of flow of an E-cylinder with 1700 psig that is running at 5 L/min?
0.9 hr
1.6 hr
7.7 hr
13.7 hr

36. Duration of flow
Duration = Gauge pressure x tank factor
liter flow
Tank Factors:
E cylinder = 0.28 L/psi (0.3)
H cylinder = 3.14 L/psi (3.0)
Full cylinder = 2200 psi

37. The respiratory therapist is using an oxygen calibrated flowmeter to administer a gas mixture of 70% helium and 30% oxygen. To deliver a flow of 8 L/min of the gas mixture to the patient, the therapist should set the oxygen flowmeter to
A.   3 L/min.
B.   5 L/min.
C.   8 L/min.
D. 11 L/min.
EXPLANATIONS:
(u) A. See explanation B.
(c) B. The correction factor for a 70%/30% helium/oxygen mixture is 1.6 X the oxygen flow. 5 L/min X 1.6 = 8 L/min.
(u) C. See explanation B.
(u) D. See explanation B.

38. You are doing quality assurance on the department’s flowmeters
You are doing quality assurance on the department’s flowmeters. After plugging in a backpressure-compensated Thorpe flowmeter, you set the flow at 10 L/min. The flowmeter outlet is partially and then completely occluded obstructed. You would expect to see the following:
The float will stay at the 10 L/min mark
The float will move upward in the flowmeter
The float will move upward and then downward in the flowmeter
The float will move downward and then drop to the bottom of the flowmeter showing zero flow

39. A. Check the bank supply lines for a leak.
While checking pressures at several oxygen outlets, the respiratory therapist notes readings near 26 psig. The hospital uses a cylinder bank bulk oxygen system. Which of the following should the therapist do first?
A. Check the bank supply lines for a leak.
B. Switch to the back-up bank of cylinders.
C. This situation requires no intervention.
D. Change patients who are receiving oxygen to E cylinders.
EXPLANATIONS:
(u) A. Checking for a leak would delay restoration of line pressure and equipment operation may be affected.
(c) B. Changing to the back-up bank would restore the system pressure and allow time for the main system to be refilled.
(h) C. Doing nothing would not solve the problem because most respiratory therapy equipment requires 50 psi to operate.
(u) D. It would take too much time to connect every patient receiving oxygen to an E cylinder and would not solve the problem. E cylinders would not provide a significant duration of adequate pressure to drive the ventilators.

40. The End

41. Your patient is wearing a face tent because of recent facial surgery
Your patient is wearing a face tent because of recent facial surgery. It is set at 35% O2. The nurse moves the patient from an upright to a supine position on the bed. What effect will this have on her respiratory status?
Increased Vt
Increased inspired O2
Increased inspired CO2
Decreased inspired O2

42. Initially the O2 percentage found in an O2 tent of a two-year-old child was found to be stable at the ordered 35%. Now less than that is found. All of the following should be tried EXCEPT:
Add an additional flowmeter and run them both at flush
Keep the tent canopy tightly tucked under the mattress
Keep the canopy flaps closed when the child is not receiving nursing care
Check the analyzer for proper function

43. An E-cylinder of O2 needs to be prepared to transport a patient
An E-cylinder of O2 needs to be prepared to transport a patient. You would look for a regulator with which pinhole locations?
1-5
2-6
3-5
2-5