Question 1

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

Accepted Answer

The transcutaneous partial pressure of carbon dioxide (PₜᴄO₂)electrode is heated to between 42° C and 45° C to produce capillary vasodilation below the surface of the electrode.This will improve diffusion of gases across the skin.If the PₜᴄO₂ temperature is lower than this range,the results will not be reliable.A temperature higher than this range will produce skin burns.

Question 2

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

Accepted Answer

Laboratory CO-oximeters measure all four types of hemoglobin by using separate wavelengths of light to identify each species,whereas pulse oximeters use only two wavelengths to quantify the amount of O₂HB and HHB present.

Question 3

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

Accepted Answer

A reduction in cutaneous circulation will dramatically affect the measurement of transcutaneous partial pressure of oxygen (PₜᴄO₂).This situation is caused by hypothermia,septic shock,and elevated peripheral resistance.PₜᴄO₂ measurements have been shown to be reliable for neonates.

Question 4

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

Accepted Answer

Plateau pressure requires the establishment of a period of no-flow for 1-2 seconds to allow pressure equilibration by the redistribution of the tidal volume and stress relaxation.This maneuver increases inspiratory time and if held longer than 2 seconds may cause barotrauma.

Question 5

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

Accepted Answer

Indirect calorimeters contain analyzers for measuring the concentration of inspired and expired gases,oxygen (O₂)and carbon dioxide (CO₂),pneumotachometers,turbine flowmeters,or ultrasonic vortex flowmeters to measure volume and flow,temperature-sensitive,solid-state transducers to measure barometric pressure and exhaled gas temperatures.

Question 6

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

Accepted Answer

Barometers are used to measure atmospheric (barometric)pressure.Older ventilators incorporated an aneroid manometer into the ventilator circuit.Variable orifice pneumotachometers are used to measure flow.The devices that are used in the current ventilators today are the electromechanical transducers,which include piezoelectric transducers,variable capacitance transducers,and strain gauge transducers.

Question 7

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

Accepted Answer

An energy expenditure (EE)of 30-40 kcal/hr/m² is normal for an adult.The EE of 20 kcal/hr/m² is less than 80% of predicted and is considered a hypometabolic state.Starvation creates a hypometabolic state.Pregnancy,hyperthyroidism,and stimulant drugs create hypermetabolic states.

Question 8

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

Accepted Answer

A heated Clark or polarographic electrode is used to monitor the transcutaneous partial pressure of oxygen.The Stow-Severinghaus electrode is used in the measurement of transcutaneous carbon dioxide (CO₂)partial pressure.Polarographic and Galvanic electrodes are types of oxygen analyzers that use chemical reactions to measure oxygen concentrations in gas mixtures.

Question 9

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

Accepted Answer

The Stow-Severinghaus electrode is used in the measurement of transcutaneous carbon dioxide partial pressure.A Clark or polarographic electrode is used to monitor the transcutaneous partial pressure of oxygen.Polarographic and Galvanic electrodes are types of oxygen analyzers that use chemical reactions to measure oxygen concentrations in gas mixtures.

Question 10

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

Accepted Answer

Burns can occur because the site of measurement needs to be heated to between 42° C and 45° C.Repositioning the sensor every 4-6 hours will help avoid this problem.

Question 11

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

Accepted Answer

Vortex ultrasonic flowmeters are not affected by the viscosity,density,or temperature of the gas being measured.The turbine and variable orifice pneumotachometer will not be accurate when using heliox because of its decreased density.A variable capacitance device is a transducer used to measure airway pressure.

Question 12

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

Accepted Answer

A healthy adult consuming a typical American diet will have a respiratory quotient (RQ)range from 0.80-0.85.An RQ of 0.7 is indicative of lipid metabolism as seen in prolonged starvation or severe sepsis.The RQ for the metabolism of pure carbohydrates is 1.0.An RQ of 0.9 would mean that the individual is consuming a higher amount of carbohydrates than a normal diet.

Question 13

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)

Accepted Answer

The electrode temperature must be documented to ensure that the temperature stays within the range of 42-45° C.The skin temperature should be noted to assess the patient's peripheral perfusion.The probe placement should be noted to ensure that the probe is being moved to different sites every 4-6 hours.The fractional inspired oxygen (FɪO₂)should be documented to determine the need for an increase or decrease in the amount of supplemental oxygen the patient is receiving.

Question 14

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?

Accepted Answer

Diets with a high percentage of carbohydrates will raise the amount of carbon dioxide (CO₂)a patient produces.This will overburden a patient with limited ventilatory reserves,as with chronic obstructive pulmonary disease (COPD).The added CO₂ is greater than the patient's ventilatory capacity,and when attempting to maintain spontaneous breathing the patient will fail to wean.

Question 15

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:
$\begin{array} { | l | l | l | l | l | } 
\hline \text { Time } & \mathrm { F } _ { 1 } \mathrm { O } _ { \mathbf { 2 } } & \begin{array} { l } 
\mathrm { PEEP } ( \mathrm { cm } \
\left. \mathrm { H } _ { \mathbf { 2 } } \mathrm { O } \right)
\end{array} & \mathrm { S } _ { \mathrm { P } } \mathrm { O } _ { \mathbf { 2 } } ( \% ) & \mathrm { P } _ { \mathbf { z t } } \mathrm { CO } _ { \mathbf { 2 } } ( \mathrm { mm } \mathrm { Hg } ) \
\hline 0600 & 0.85 & 5 & 88 & 30 \
\hline 0630 & 0.85 & 8 & 88 & 30 \
\hline 0650 & 0.85 & 10 & 90 & 32 \
\hline 0720 & 0.80 & 12 & 93 & 34 \
\hline 0740 & 0.80 & 15 & 90 & 25 \
\hline
\end{array}$
At 0740 the single-breath carbon dioxide (SBCO₂)curve shifted to the right.What action should the respiratory therapist take at this time?

Accepted Answer

The increase in positive end-expiratory pressure (PEEP)to 15 cm H₂O seems to have decreased pulmonary perfusion because of overinflation of the alveoli.This is evident by the decrease in the partial pressure of end-tidal carbon dioxide (PₑₜCO₂)to 25 mm Hg and the right shift in the single-breath carbon dioxide (SBCO₂)curve.Increasing the fractional inspired oxygen (FɪO₂)will not address this problem.Reducing the set tidal volume will increase the PₑₜCO₂ but will not improve the pulmonary circulation.Continuing to increase the PEEP will further reduce pulmonary perfusion and cause more dead space.Reducing the PEEP back to 12 cm H₂O will optimize the PEEP and reduce overinflation.

Question 16

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?

Accepted Answer

The respiratory quotient (RQ)is the ratio of carbon dioxide (CO₂)production to oxygen (O₂)consumption.This patient has an RQ (390/375)of 1.04.Ketosis causes the RQ to be less than 0.7.Severe sepsis is associated with RQ levels of approximately 0.7.Hyperventilation is associated with RQ levels greater than 1.0.Pure carbohydrate RQ is 1.0.

Question 17

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

Accepted Answer

See Box 10-3 in the text for a list of conditions that reduce and elevate levels of exhaled nitric oxide.

Question 18

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

Accepted Answer

An energy expenditure (EE)of 30-40 kcal/hr/m² is normal for an adult.The EE of 60 kcal/hr/m² is greater than 120% of predicted and is considered a hypermetabolic state.Burns create a hypermetabolic state.Starvation,sedation,and hypothermia create hypometabolic states.

Question 19

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

Accepted Answer

Exhaled nitric oxide (NO)is currently used as a marker for airway inflammation associated with asthma.Monitoring the level of exhaled NO can also be used to monitor the effectiveness of inhaled corticosteroid in the treatment of asthmatic patients.

Question 20

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

Accepted Answer

A signal drift on a transcutaneous monitor should be addressed by changing the electrode and sensor's membrane.The electrode and the sensor's membrane should be changed weekly due to the evaporation of the electrolyte solution caused by the heating of the electrode.Increasing the probe temperature may cause patient burns if it is over 45° C.The signal drift does not necessarily mean that the monitor itself needs to be taken out of service.Adding more gel to the patient's skin will help with gas diffusion during measurement only.

Quiz 10: Assessment of Respiratory Function

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

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

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

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

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

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

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

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

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

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

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

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

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 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 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?

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

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

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

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