TMC PRACTICE QUESTIONS AND ANSWERS(iv)
A patient receiving O2 via concentrator at 2L/min at home complains he can't feel O2 coming
out the prongs of the cannula. Which of the following should the RT do first?
a. Place the cannula under water and see if bubbling occurs
b. Attach the cannula to a cylinder/flowmeter setup
c. Increase the flow to 5L/min
d. Replace the concentrator with a new one Correct Answer: a. Place the cannula under water
and see if bubbling occurs
The first step is to check to make sure there is flow passing through the cannula by having the
patient remove the cannula and place it in a cup of water. Bubbling will occur if there is flow. If
no bubbling occurs, the patient should make sure the cannula is attached to the flowmeter outlet
and the flowmeter is turned on. If there's any doubt, the patient should connect the cannula to the
cylinder back-up and call the home care company.
A pt is breathing 16 times per minute and has a Vt of 450mL. What is this pt's minute
ventilation?
a. 4.2L
b. 6.1L
c. 7.2L
d. 8.6L Correct Answer: c. 7.2L
Vt x R = Ve
A pt is breathing spontaneously using a 50% aerosol mask with the following ABG:
ph: 7.36
CO2: 43
O2: 48
HCO3: 24
Based on this information, the most appropriate recommendation is which of the following?
a. Initiate CPAP
b. Increase the O2 percentage to 70%
c. Change to a nonrebreathing mask
d. Change to a simple O2 mask at 10L/min Correct Answer: a. Initiate CPAP
A PaO2 of 55 mm Hg on 50% oxygen indicates refractory hypoxemia. Increasing the FIO2 most
likely won't improve the PaO2 in addition to increasing the potential for lung damage. Applying
CPAP to help recruit alveoli and allow for more surface area for oxygen to be able to enter the
blood is more appropriate
A pt is receiving mechanical ventilation with the following settings
, Vt: 750
RR: 12
Mode: AC
PEEP: 10
FiO2: 80%
pH: 7.41
CO2: 38
O2: 174
Based on these information, what would be the appropriate ventilator settings?
a. Decrease PEEP to 8
b. Decrease FiO2 to 70%
c. Decrease Vt to 650
d. Increase Insp. Flow Correct Answer: b. Decrease FiO2 to 70%
Because the patient is hyperoxygenating, the PaO2 may be decreased by reducing FIO2 or PEEP.
Because the FIO2 is 0.80, it should be reduced first. Once the FIO2 is 0.50-0.60, the PEEP
should then be decreased.
The reduction in urinary output caused by mechanical ventilation may be the result of
1. Decreased renal blood flow
2. Decreased production of ADH
3. Increased renal blood flow
4. Increased production ofADH
a. 1 only
b. 1 and 4
c. 2 and 3
d. 3 and 4 Correct Answer: b. 1 and 4
Positive pressure ventilation has the potential for decreasing venous blood return to the heart.
This results from this pressure being transferred to the superior and inferior vena cavae, which
restricts blood flow back into the heart. Baroreceptors (pressure receptors) sense this lower
pressure in the right atrium and send signals to the brain, which causes an increased production
of ADH by the pituitary gland. This causes the body to hold on to more fluid as a compensatory
mechanism because the right side of the heart is sensing a low pressure. The decreased cardiac
output results in decreased perfusion to the kidneys, which also reduces urine output.
Which values indicate that a patient is most likely ready to be weaned from mechanical
ventilation?
1. Vd/Vt Ratio of .45
2. MIP of -31cmH2O
3. RSBI of 145
4. VC of 8
A patient receiving O2 via concentrator at 2L/min at home complains he can't feel O2 coming
out the prongs of the cannula. Which of the following should the RT do first?
a. Place the cannula under water and see if bubbling occurs
b. Attach the cannula to a cylinder/flowmeter setup
c. Increase the flow to 5L/min
d. Replace the concentrator with a new one Correct Answer: a. Place the cannula under water
and see if bubbling occurs
The first step is to check to make sure there is flow passing through the cannula by having the
patient remove the cannula and place it in a cup of water. Bubbling will occur if there is flow. If
no bubbling occurs, the patient should make sure the cannula is attached to the flowmeter outlet
and the flowmeter is turned on. If there's any doubt, the patient should connect the cannula to the
cylinder back-up and call the home care company.
A pt is breathing 16 times per minute and has a Vt of 450mL. What is this pt's minute
ventilation?
a. 4.2L
b. 6.1L
c. 7.2L
d. 8.6L Correct Answer: c. 7.2L
Vt x R = Ve
A pt is breathing spontaneously using a 50% aerosol mask with the following ABG:
ph: 7.36
CO2: 43
O2: 48
HCO3: 24
Based on this information, the most appropriate recommendation is which of the following?
a. Initiate CPAP
b. Increase the O2 percentage to 70%
c. Change to a nonrebreathing mask
d. Change to a simple O2 mask at 10L/min Correct Answer: a. Initiate CPAP
A PaO2 of 55 mm Hg on 50% oxygen indicates refractory hypoxemia. Increasing the FIO2 most
likely won't improve the PaO2 in addition to increasing the potential for lung damage. Applying
CPAP to help recruit alveoli and allow for more surface area for oxygen to be able to enter the
blood is more appropriate
A pt is receiving mechanical ventilation with the following settings
, Vt: 750
RR: 12
Mode: AC
PEEP: 10
FiO2: 80%
pH: 7.41
CO2: 38
O2: 174
Based on these information, what would be the appropriate ventilator settings?
a. Decrease PEEP to 8
b. Decrease FiO2 to 70%
c. Decrease Vt to 650
d. Increase Insp. Flow Correct Answer: b. Decrease FiO2 to 70%
Because the patient is hyperoxygenating, the PaO2 may be decreased by reducing FIO2 or PEEP.
Because the FIO2 is 0.80, it should be reduced first. Once the FIO2 is 0.50-0.60, the PEEP
should then be decreased.
The reduction in urinary output caused by mechanical ventilation may be the result of
1. Decreased renal blood flow
2. Decreased production of ADH
3. Increased renal blood flow
4. Increased production ofADH
a. 1 only
b. 1 and 4
c. 2 and 3
d. 3 and 4 Correct Answer: b. 1 and 4
Positive pressure ventilation has the potential for decreasing venous blood return to the heart.
This results from this pressure being transferred to the superior and inferior vena cavae, which
restricts blood flow back into the heart. Baroreceptors (pressure receptors) sense this lower
pressure in the right atrium and send signals to the brain, which causes an increased production
of ADH by the pituitary gland. This causes the body to hold on to more fluid as a compensatory
mechanism because the right side of the heart is sensing a low pressure. The decreased cardiac
output results in decreased perfusion to the kidneys, which also reduces urine output.
Which values indicate that a patient is most likely ready to be weaned from mechanical
ventilation?
1. Vd/Vt Ratio of .45
2. MIP of -31cmH2O
3. RSBI of 145
4. VC of 8
