Deck 10: Assessment of Respiratory Function

Question 1

A pulse oximeter differentiates oxyhemoglobin from deoxygenated hemoglobin by which of the following methods?

A) Relating cyclical changes in light transmission through the sampling site.
B) Shining and comparing two wavelengths of light through the sampling site.
C) Direct measurement by a heated polarographic electrode applied to the skin.
D) Using a color sensing device that absorbs one wavelength of light through the skin.

Answer 1

B
A pulse oximeter uses spectrophotometry to differentiate between oxyhemoglobin and deoxygenated hemoglobin.Two wavelengths of light (660 and 940 nm)are shined through a sample site.Oxyhemoglobin absorbs more light at 940 nm (infrared [IR] light)than does deoxygenated hemoglobin.Deoxyhemoglobin absorbs more light at 660 nm.The use of cyclical changes in light transmission measured at the sampling site is the method to determine the pulse rate with a pulse oximeter.A heated polarographic electrode is used for transcutaneous partial pressure of oxygen (PₜᴄO₂)measurements.A color sensing device is used to detect the amount of carbon dioxide in exhaled gas.

Question 2

During shift report,the day shift respiratory therapist informs the night shift respiratory therapist about a freshly postoperative patient who is receiving full support via mechanical ventilation.At the time of the last patient-ventilator system check the patient had not awaken from anesthesia.During first round on the day shift the respiratory therapist notes the capnography shown in the figure.The most appropriate action to take would be to do which of the following?

A) Administer a bronchodilator.
B) Begin the weaning process.
C) Fix the leak in the sampling line.
D) Reinflate the ET tube cuff.

Answer 2

Begin the weaning process.

Question 3

A patient receiving mechanical ventilation is being continuously monitored for oxygen saturation measured by pulse oximeter (SₚO₂)for the past 48 hours.When initially applied,the SₚO₂ and the arterial oxygen saturation (SₐO₂),as well as the pulse on the pulse oximeter,ECG,and manual pulse,were consistent.During clinical rounds,the respiratory therapist notices that although the probe is appropriately placed and capillary refill is normal,the SₚO₂ reading is down to 90% from 95%.The most appropriate immediate action is to do which of the following?

A) Replace the probe.
B) Reposition the patient.
C) DRₐᴡan arterial blood gas.
D) Move the probe to a different site.

Answer 3

C
The oxygen saturation measured by pulse oximeter (SₚO₂)has dropped from 95% to 90%.Since the SₚO₂ and arterial oxygen saturation (SₐO₂)previously correlated,this situation could mean that the patient is becoming hypoxemic.The probe is appropriately placed,so changing sites is not appropriate.The patient has already been checked for and has adequate circulation to the site of the probe,so moving the probe to a site with more perfusion is not appropriate.Therefore,the patient needs to have an arterial blood gas to ascertain the SₐO₂ and partial pressure of oxygen (PₐO₂).

Question 4

Pulse oximetry is most useful in which of the following situations?

A) Determining when to extubate an adult
B) Prescribing oxygen therapy for neonates
C) Monitoring patients undergoing chest physical therapy
D) Establishing initial oxygen necessity for home care patients

Question 5

The respiratory therapist has just stopped postural drainage for a 24-year-old patient with cystic fibrosis because of shortness of breath and slight cyanosis in the "head-down" position.The respiratory therapist should recommend which of the following adjustments to therapy?

A) Continue postural drainage and monitor patient with capnography.
B) Use only upright or flat postural drainage positions and dRₐᴡan arterial blood gas (ABG).
C) Administer oxygen via nasal cannula and monitor with pulse oximetry.
D) Use a transcutaneous partial pressure of oxygen (PₜᴄO₂) monitor to assess the extent of hypoxemia.

Question 6

The change in the single-breath carbon dioxide (CO₂)curve from "A" to "B" shown in the figure may be a result of which of the following?

A) Hypervolemia
B) Decreased positive end-expiratory pressure (PEEP)
C) Increased mean airway pressure
D) Excessive bronchodilator administration

Question 7

The area under the curve of a single-breath carbon dioxide (SBCO₂)curve represents which of the following?

A) Tidal volume
B) Alveolar dead space
C) Physiologic dead space
D) Effective alveolar ventilation

Question 8

A pulse oximeter reading will be most accurate when used with a patient in which of the following situations?

A) An intensive care unit patient with hyperbilirubinemia
B) A hypotensive patient receiving peripheral vasoconstrictors
C) An emergency department patient with evidence of smoke inhalation
D) An open heart patient receiving extracorporeal membrane oxygenation

Question 9

The capnogram in the figure is indicative of which of the following conditions?

A) Chronic obstructive pulmonary disease (COPD)
B) Cardiac arrest
C) Hyperventilation
D) Pulmonary embolism

Question 10

For a given minute ventilation,partial pressure of end-tidal carbon dioxide (PₑₜCO₂)is a function of which of the following?1.Metabolic rate
2)Cardiac output
3)Alveolar dead space
4)Physiologic shunt

A) 1 and 3 only
B) 1, 2, and 3 only
C) 2, 3, and 4 only
D) 1, 2, 3, and 4

Question 11

During which phase of a capnogram does inhalation occur?

A) Phase 1
B) Phase 2
C) Phase 3
D) Phase 4

Question 12

While trying to use a finger probe to assess a patient's oxygenation status,the respiratory therapist finds that the pulse rate and the ECG monitor heart rate are not consistent and the oxygen saturation measured by pulse oximeter (SₚO₂)reading is blank.The patient is awake,alert,and in no obvious respiratory distress.The respiratory therapist should first take which of the following actions?
1)Change the probe site.
2)DRₐᴡan arterial blood gas.
3)Adjust the probe position on the finger.
4)Remove the probe,and perform a capillary refill test.

A) 1 and 2 only
B) 2 and 3 only
C) 3 and 4 only
D) 1 and 4 only

Question 13

The normal range for arterial-to-end-tidal partial pressure of carbon dioxide [P₍ₐ₋ₑₜ₎CO₂] is which of the following?

A) 2-4 mm Hg
B) 4-6 mm Hg
C) 6 -8 mm Hg
D) 8-10 mm Hg

Question 14

A patient arrives in the emergency department via ambulance following rescue from a house fire.The instrument that would be most appropriate to assist the respiratory therapist in assessing this patient's oxygenation status is which of the following?

A) Capnograph
B) Pulse oximeter
C) Calorimeter
D) CO-oximeter

Question 15

A patient in the intensive care unit is receiving mechanical ventilation,has a pulmonary artery catheter in place,and is being monitored continuously with a capnometer.The patient's arterial partial pressure of carbon dioxide (PₐCO₂)is 41 mm Hg and the partial pressure of end-tidal carbon dioxide (PₑₜCO₂)is 36 mm Hg.There is a sudden decrease in the PₑₜCO₂ to 18 mm Hg causing an alarm to sound.The most likely cause of this development is which of the following?

A) Hypovolemia
B) Apneic episode
C) Pulmonary embolism
D) Increased cardiac output

Question 16

The area represented by the letter "Y" in the figure is which of the following?

A) End-tidal carbon dioxide (EtCO₂)
B) Alveolar ventilation
C) Alveolar dead space
D) Airway dead space

Question 17

During which phase of a capnograph does alveolar gas containing carbon dioxide (CO₂)mix with gas from the anatomical airways and the CO₂ concentration rises?

A) Phase 1
B) Phase 2
C) Phase 3
D) Phase 4

Question 18

Which of the following situations will cause an increase in the single-breath carbon dioxide (SBCO₂)curve?

A) Decreased metabolic rate and decreased ventilation
B) Decreased metabolic rate and increased ventilation
C) Increased metabolic rate and increased ventilation
D) Increased metabolic rate and decreased ventilation

Question 19

An arterial blood gas should be done to confirm pulse oximetry findings less than a minimum of _____________.

A) 60%
B) 70%
C) 80%
D) 90%

Question 20

The partial pressure of end-tidal carbon dioxide (PₑₜCO₂)reading is taken at what point in the figure?

A) Point A
B) Point B
C) Point C
D) Point D

Question 21

To properly operate,the transcutaneous partial pressure of oxygen electrode needs to be at what temperature range?

A) 32-35° C
B) 36-39° C
C) 42-45° C
D) 46-49° C

Question 22

Which of the following actions is indicated when a disparity exists between SₚO₂,SₐO₂,and the clinical presentation of a patient?

A) Move the probe to an alternate site to check for SₚO₂.
B) Replace the pulse oximeter probe.
C) Measure arterial oxygen saturation by CO-oximetry.
D) Disregarding the SₐO₂.

Question 23

A transcutaneous partial pressure of oxygen (PₜᴄO₂)reading is reliable in which of the following situations?

A) Hypothermia
B) Septic shock
C) Infant respiratory distress syndrome
D) Elevated peripheral (cutaneous) resistance

Question 24

To measure plateau pressure,inspiration should be held for how many seconds?

A) 1-2
B) 2-3
C) 3-4
D) 4⁻⁵

Question 25

Components of an indirect calorimeter may include which of the following?1.Pressure manometer
2)Pneumotachometer
3)Pressure-sensitive transducer
4)Oxygen and carbon dioxide analyzers

A) 1 and 2 only
B) 2 and 4 only
C) 2, 3, and 4 only
D) 1, 2, 3, and 4

Question 26

The newest types of mechanical ventilators use which of the following devices to measure airway pressures?

A) Barometers
B) Aneroid manometers
C) Electromechanical transducers
D) Variable orifice pneumotachometers

Question 27

An energy expenditure (EE)of 20 kcal/hr/m² for an adult is indicative of which of the following conditions?

A) Pregnancy
B) Starvation
C) Hyperthyroidism
D) Stimulant drugs

Question 28

What type of electrode is used by a transcutaneous partial pressure of oxygen (PₜᴄO₂)device?

A) Galvanic
B) Polarographic
C) Paramagnetic
D) Stow-Severinghaus

Question 29

What type of electrode is used by a transcutaneous partial pressure of carbon dioxide (PₜᴄO₂)device?

A) Galvanic
B) Polarographic
C) Paramagnetic
D) Stow-Severinghaus

Question 30

How often should the respiratory therapist reposition the sensor of a transcutaneous monitor?

A) 30 minutes to 1 hour
B) 1-3 hours
C) 4-6 hours
D) 7-9 hours

Question 31

Select the ventilator flowmeter that will read accurately when used with heliox.

A) Turbine
B) Vortex ultrasonic
C) Variable capacitance
D) Variable orifice pneumotachometer

Question 32

The respiratory quotient (RQ)value associated with substrate utilization patterns in normal,healthy individuals is which of the following?

A) 0.7
B) 0.8
C) 0.9
D) 1.0

Question 33

The clinical data that should be recorded when making transcutaneous measurements include which of the following?1.Electrode temperature
2)Skin temperature
3)Probe placement
4)Fractional inspired oxygen (FɪO₂)

A) 1 and 3 only
B) 1 and 2 only
C) 2, 3, and 4 only
D) 1, 2, 3, and 4

Question 34

A mechanically ventilated patient with chronic obstructive pulmonary disease is in the process of being weaned from mechanical ventilation.A diet containing which of the following will be most beneficial to this process?

A) High protein, low fats, and carbohydrates
B) Low fats and proteins, high carbohydrates
C) Low carbohydrate with increased fats and proteins
D) Equal amounts of carbohydrates, fats, and proteins

Question 35

A patient is receiving mechanical ventilation with a fractional inspired oxygen (FɪO₂)of 0.85 and a positive end-expiratory pressure (PEEP)of 5 cm H₂O.His arterial partial pressure of oxygen (PₐO₂)is 68 mm Hg,arterial oxygen saturation (SₐO₂)is 88%,and partial pressure of end-tidal carbon dioxide (PₑₜCO₂)is 32 mm Hg.Over the next few minutes his PEEP is titrated resulting in the following data:

At 0740 the single-breath carbon dioxide (SBCO₂)curve shifted to the right.What action should the respiratory therapist take at this time?

A) Increase the FɪO₂ to 0.90.
B) Reduce the set tidal volume.
C) Continue to increase the PEEP.
D) Reduce the PEEP to 12 cm H₂O.

Question 36

A patient whose carbon dioxide (CO₂)production is 390 mL/min and oxygen (O₂)consumption is 375 mL/min is most likely experiencing which of the following?

A) Ketosis
B) Severe sepsis
C) Hyperventilation
D) Too much carbohydrate intake

Question 37

The condition that is associated with a reduction in exhaled nitric oxide is which of the following?

A) Alveolitis
B) Cystic fibrosis
C) Chronic bronchitis
D) Airway viral infection

Question 38

An energy expenditure (EE)of 60 kcal/hr/m² for an adult is indicative of which of the following conditions?

A) Burns
B) Sedation
C) Starvation
D) Hypothermia

Question 39

Exhaled nitric oxide is used to monitor the effectiveness of which drug used in the treatment of asthma?

A) Anticholinergic bronchodilators
B) Beta adrenergic bronchodilators
C) Inhaled corticosteroids
D) Leukotriene inhibitors

Question 40

During calibration of a transcutaneous monitor the respiratory therapist notices a signal drift.The respiratory therapist should do which of the following?

A) Increase the probe temperature.
B) Replace the monitor and call for repair.
C) Add more electrolyte gel to the patient's skin.
D) Change the electrolyte and sensor's membrane.

Question 41

A patient-ventilator system check reveals the following information: peak inspiratory pressure (PIP)32 cm H₂O,positive end-expiratory pressure (PEEP)12 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)20 cm H₂O,inspiratory time (Tɪ)1 second,and set frequency 12/min.Calculate the mean airway pressure.

A) 4 cm H₂O
B) 8 cm H₂O
C) 12 cm H₂O
D) 14 cm H₂O

Question 42

Calculate the dynamic compliance given the following clinical data: tidal volume 500 mL,peak inspiratory time (PIP)35 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)20 cm H₂O,positive end-expiratory pressure (PEEP)5 cm H₂O,and tubing compliance (Cᴛ)2.5 mL/cm H₂O.

A) 11.8 mL/cm H₂O
B) 14.2 mL/cm H₂O
C) 25 mL/cm H₂O
D) 46.2 mL/cm H₂O

Question 43

Bidirectional flow can be measured by which of the following devices?

A) Turbine flowmeter
B) Piezoelectric transducer
C) Ultrasonic vortex flowmeter
D) Variable orifice pneumotachometer

Question 44

Calculate the static compliance given the following clinical data: tidal volume 600 mL,peak inspiratory pressure (PIP)40 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)30 cm H₂O,positive end-expiratory pressure (PEEP)15 cm H₂O,and tubing compliance Cᴛ2 mL/cm H₂O.

A) 14.5 mL/cm H₂O
B) 38 mL/cm H₂O
C) 55 mL/cm H₂O
D) 58 mL/cm H₂O

Question 45

Calculate dynamic compliance given the following clinical data: tidal volume 600 mL,peak inspiratory pressure (PIP)28 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)15 cm H₂O,positive end-expiratory pressure (PEEP)10 cm H₂O,and CT 2 mL/cm H₂O.

A) 30.2 mL/cm H₂O
B) 31.3 mL/cm H₂O
C) 38 mL/cm H₂O
D) 44.1 mL/cm H₂O

Question 46

Calculate the static compliance given the following clinical data: tidal volume 500 mL,peak inspiratory pressure (PIP)35 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)25 cm H₂O,positive end-expiratory pressure (PEEP)12 cm H₂O,measured unintended positive end-expiratory pressure (auto-PEEP)3 cm H₂O,and tubing compliance (Cᴛ)2.5 mL/cm H₂O.

A) 17.5 mL/cm H₂O
B) 34 mL/cm H₂O
C) 36 mL/cm H₂O
D) 47.5 mL/cm H₂O

Question 47

At which point in the pressure-time curve of a spontaneous breath should the transdiaphragmatic pressure be greatest?

A) Mid-inspiration
B) Mid-expiration
C) End of exhalation
D) Beginning of inspiration

Question 48

A patient-ventilator system check reveals the following information: peak inspiratory pressure (PIP)27 cm H₂O,positive end-expiratory pressure (PEEP)5 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)14 cm H₂O,inspiratory time (Tɪ)0.75 second,and set frequency 20/minute.Calculate the mean airway pressure.

A) 6.75 cm H₂O
B) 7.75 cm H₂O
C) 11.75 cm H₂O
D) 12.37 cm H₂O

Question 49

An increase in intrinsic work of breathing due to a decrease in static compliance is caused by which of the following?

A) Emphysema
B) Bronchospasm
C) Pulmonary fibrosis
D) Airway inflammation

Question 50

Calculate the airway resistance given the following clinical data: flow rate 60 L/min,PIP 28 cm H₂O,Pₚₗₐₜₑₐᵤ 21 cm H₂O,and PEEP 8 cm H₂O.

A) 7 cm H₂O/L/sec
B) 13 cm H₂O/L/sec
C) 20 cm H₂O/L/sec
D) 28 cm H₂O/L/sec

Question 51

The energy required to move gas through the airways and expand the thorax is known as which of the following?

A) Airway resistance
B) Dynamic compliance
C) Intrinsic work of breathing
D) Extrinsic work of breathing

Question 52

Calculate the airway resistance given the following clinical data: flow rate 60 L/min,peak inspiratory pressure (PIP)42 cm H₂O,plateau pressure (Pₚₗₐₜₑₐᵤ)15 cm H₂O,and positive end-expiratory pressure (PEEP)5 cm H₂O.

A) 10 cm H₂O/L/sec
B) 30 cm H₂O/L/sec
C) 37 cm H₂O/L/sec
D) 42 cm H₂O/L/sec

Question 53

During the application of positive end-expiratory pressure (PEEP),the monitoring of which pressure will alert the respiratory therapist specifically to alveolar overdistention?

A) Peak inspiratory pressure (PIP)
B) Plateau pressure (Pₚₗₐₜₑₐᵤ)
C) Mean airway pressure
D) Transairway pressure (Pᴛᴀ)

Question 54

Which of these two parameters does a pulse oximeter measure?
1)O₂Hb
2)Hb
3)COHb
4)MetHb

A) 1 and 2
B) 1 and 3
C) 2 and 3
D) 3 and 4

Question 55

The best assessment of the function of the diaphragm during inspiration is obtained by measuring which of the following?

A) Airway resistance
B) Pressure-time product
C) Pressure-volume curve
D) Maximum inspiratory pressure