Certified Respiratory Therapist (CRT) – NBRC TMC Exam |
Practice Questions and Answers for 2024–2025 Certification
This document provides targeted practice questions and verified answers for the
NBRC TMC Exam, designed to prepare candidates for Certified Respiratory
Therapist (CRT) certification. It covers all core content areas, including patient data
evaluation, airway management, mechanical ventilation, respiratory care
pharmacology, and diagnostic procedures. Perfect for respiratory therapy students
and professionals seeking to pass the TMC exam and earn CRT credentials.
1. You measure an oxygen concentration of 55% being delivered by an air-
entrainment mask set to deliver 31% oxygen.: C). Check the entrainment ports.
Because air-entrainment masks mix air and oxygen at a constant ratio, an alteration
in the delivered oxygen concentration could result only from an alteration in the
mixing ratio. Since jet size (for a given adapter) is fixed, the problem must be with
the entrainment ports. Obstruction of the entrainment ports will decrease air
entrainment and raise the delivered oxygen concentration.
2. Which of the following is the approximate total output flow delivered
from a 35% air-entrainment mask operating at 8L/min?: B). 48L/min
To compute the total output flow delivered by an air-entrainment device, multiply the
sum of its ratio parts by the input flow. A 35% air-entrainment mask mixes air and
oxygen at a fixed 5:1 ratio; thus (5+1) x 8 = 48 L/min
3. You observed that the reservoir bag on a patient receiving O2 at 10 L/min
does not deflate at all when the patient inspires. What to do first.: C). Check
the mask for a snug fit.
,If a nonrebreathing mask reservoir bag does not deflate at all when the patient
inspires, either the flow is higher than needed, there are large inspiratory air leaks
(around the mask or through the exhalation valves), or the inspiratory valve is
jammed. The most common cause is large air leakage, which can easily be
corrected by making sure that the mask is fit comfortably tight to the patient,s face.
4. Which of the following is the most probable cause of insufficient mist in
a croup tent)?: D). A clogged capillary tube in the nebulizer.
Since most croup tents use large-volume jet nebulizers to generate mist, insufficient
mist indicates malfunction of the nebulizer. The most common cause of nebulizer
malfunction is clogging of the capillary tube that feeds liquid water to the jet.
5. A physician specifies in her respiratory orders the following objective for
a patient with an artificial airway: " to overcome the patient's humidity deficit."
Aerosol generator to be used for this patient.: B). Large -reservoir heated jet
nebulizer.
The large-reservoir air-entrainment jet nebulizer is the primary gas-powered aerosol
generator used to provide humidification to the respiratory tract.
6. During CPR, the oxygen reservoir bag of a bag-valve manual resuscitator
collapses during the refill phase. You can correct this problem by:: B).
Increasing O2 flow to the bag.
Think of the reservoir bag of a bag-valve manual resuscitator as equivalent to the
bag on a reservoir mask. If the reservoir bag collapses during the resuscitator's
refill phase (equivalent to patient inspiration), the flow is inadequate and should be
increased until the bag does not empty.
7. While a patient is being ventilated with a bag-valve resuscitator, the bag
fills rapidly and collapses on minimal pressure, although little chest
movement by the patient is noted. The cause may be.: A). Absence of the inlet
valve.
If a bag-valve resuscitator fills rapidly but collapses on minimal pressure and
delivers little volume, the likely problem is a missing, torn or malpositioned inlet
valve. In this case, when you squeeze the bag, gas follows the path of least
resistance and escapes out the inlet port (instead of going to the patient). Can be
avoided by performing an operational check on the bag before applying it to the
patient.
, 8. An intubated adult patient with severe expiratory airway obstruction
requires ventilatory support. Which of the following factors is most important
in selecting a ventilator for this patient?: B). Variable flow control and adjustable
I:E ratios.
Of the functions listed, the most important capability when selecting a ventilator for
an intubated adult patient with severe expiratory airway obstruction would be
variable flow control and adjustable I:E ratios. This will allow clinicians to make sure
the expiratory time is sufficiently long to prevent air trapping / auto-PEEP
9. What type of breathing circuit would you use when assembling a home-
care ventilator.: B). Single-limb circuit with expiratory balloon valve.
Most home-care ventilators use a single-limb circuit with expiratory balloon valve.
Single-limb circuits have a separate pneumatic line running from the ventilator to
the expiratory valve that pressurizes the expiratory valve during inspiration in
order to block gas outflow during the application of positive pressure. An
expiratory valve can also be used to control or retard expiratory flow or provide
CPAP/PEEP.
10. To provide a low to moderate concentration of oxygen to a patient
receiving nasal BIPAP via a device that uses a turbine or blower to generate
pressure, you should:: C). Bleed supplemental O2 from a flowmeter into the
circuit.
Most NPPV ventilators and BIPAP devices use a simple air blower to generate
pressure. In order to provide supplemental oxygen with devices, you place a small-
bore tubing adapter at either the patient interface or machine outlet. After
connecting this adapter to a flowmeter via O2 delivery tubing, you bleed O2 into the
circuit until he desired level is confirmed by O2 analysis. Note that high
supplemental O2 flows can interfere with the proper triggering or cycling of some
NPPV ventilators.
11. What alarm conditions indicates a potential system leak when delivering
volume-oriented ventilatory support?: D). Low volume + low pressure.
When delivering volume-oriented ventilatory support, potential system leaks are
indicated by a low-volume and low-pressure alarm condition. Check for and
correct any loose circuit connections.
Practice Questions and Answers for 2024–2025 Certification
This document provides targeted practice questions and verified answers for the
NBRC TMC Exam, designed to prepare candidates for Certified Respiratory
Therapist (CRT) certification. It covers all core content areas, including patient data
evaluation, airway management, mechanical ventilation, respiratory care
pharmacology, and diagnostic procedures. Perfect for respiratory therapy students
and professionals seeking to pass the TMC exam and earn CRT credentials.
1. You measure an oxygen concentration of 55% being delivered by an air-
entrainment mask set to deliver 31% oxygen.: C). Check the entrainment ports.
Because air-entrainment masks mix air and oxygen at a constant ratio, an alteration
in the delivered oxygen concentration could result only from an alteration in the
mixing ratio. Since jet size (for a given adapter) is fixed, the problem must be with
the entrainment ports. Obstruction of the entrainment ports will decrease air
entrainment and raise the delivered oxygen concentration.
2. Which of the following is the approximate total output flow delivered
from a 35% air-entrainment mask operating at 8L/min?: B). 48L/min
To compute the total output flow delivered by an air-entrainment device, multiply the
sum of its ratio parts by the input flow. A 35% air-entrainment mask mixes air and
oxygen at a fixed 5:1 ratio; thus (5+1) x 8 = 48 L/min
3. You observed that the reservoir bag on a patient receiving O2 at 10 L/min
does not deflate at all when the patient inspires. What to do first.: C). Check
the mask for a snug fit.
,If a nonrebreathing mask reservoir bag does not deflate at all when the patient
inspires, either the flow is higher than needed, there are large inspiratory air leaks
(around the mask or through the exhalation valves), or the inspiratory valve is
jammed. The most common cause is large air leakage, which can easily be
corrected by making sure that the mask is fit comfortably tight to the patient,s face.
4. Which of the following is the most probable cause of insufficient mist in
a croup tent)?: D). A clogged capillary tube in the nebulizer.
Since most croup tents use large-volume jet nebulizers to generate mist, insufficient
mist indicates malfunction of the nebulizer. The most common cause of nebulizer
malfunction is clogging of the capillary tube that feeds liquid water to the jet.
5. A physician specifies in her respiratory orders the following objective for
a patient with an artificial airway: " to overcome the patient's humidity deficit."
Aerosol generator to be used for this patient.: B). Large -reservoir heated jet
nebulizer.
The large-reservoir air-entrainment jet nebulizer is the primary gas-powered aerosol
generator used to provide humidification to the respiratory tract.
6. During CPR, the oxygen reservoir bag of a bag-valve manual resuscitator
collapses during the refill phase. You can correct this problem by:: B).
Increasing O2 flow to the bag.
Think of the reservoir bag of a bag-valve manual resuscitator as equivalent to the
bag on a reservoir mask. If the reservoir bag collapses during the resuscitator's
refill phase (equivalent to patient inspiration), the flow is inadequate and should be
increased until the bag does not empty.
7. While a patient is being ventilated with a bag-valve resuscitator, the bag
fills rapidly and collapses on minimal pressure, although little chest
movement by the patient is noted. The cause may be.: A). Absence of the inlet
valve.
If a bag-valve resuscitator fills rapidly but collapses on minimal pressure and
delivers little volume, the likely problem is a missing, torn or malpositioned inlet
valve. In this case, when you squeeze the bag, gas follows the path of least
resistance and escapes out the inlet port (instead of going to the patient). Can be
avoided by performing an operational check on the bag before applying it to the
patient.
, 8. An intubated adult patient with severe expiratory airway obstruction
requires ventilatory support. Which of the following factors is most important
in selecting a ventilator for this patient?: B). Variable flow control and adjustable
I:E ratios.
Of the functions listed, the most important capability when selecting a ventilator for
an intubated adult patient with severe expiratory airway obstruction would be
variable flow control and adjustable I:E ratios. This will allow clinicians to make sure
the expiratory time is sufficiently long to prevent air trapping / auto-PEEP
9. What type of breathing circuit would you use when assembling a home-
care ventilator.: B). Single-limb circuit with expiratory balloon valve.
Most home-care ventilators use a single-limb circuit with expiratory balloon valve.
Single-limb circuits have a separate pneumatic line running from the ventilator to
the expiratory valve that pressurizes the expiratory valve during inspiration in
order to block gas outflow during the application of positive pressure. An
expiratory valve can also be used to control or retard expiratory flow or provide
CPAP/PEEP.
10. To provide a low to moderate concentration of oxygen to a patient
receiving nasal BIPAP via a device that uses a turbine or blower to generate
pressure, you should:: C). Bleed supplemental O2 from a flowmeter into the
circuit.
Most NPPV ventilators and BIPAP devices use a simple air blower to generate
pressure. In order to provide supplemental oxygen with devices, you place a small-
bore tubing adapter at either the patient interface or machine outlet. After
connecting this adapter to a flowmeter via O2 delivery tubing, you bleed O2 into the
circuit until he desired level is confirmed by O2 analysis. Note that high
supplemental O2 flows can interfere with the proper triggering or cycling of some
NPPV ventilators.
11. What alarm conditions indicates a potential system leak when delivering
volume-oriented ventilatory support?: D). Low volume + low pressure.
When delivering volume-oriented ventilatory support, potential system leaks are
indicated by a low-volume and low-pressure alarm condition. Check for and
correct any loose circuit connections.
