Ch. 7 Test, Final Considerations in Vent Setup Flashcards
What fractional inspired oxygen (FIO2) setting should be set on the ventilator when the patient currently has a partial pressure of oxygen (PaO2) of 53 mm Hg while receiving 50% oxygen and the desired PaO2 is 90 mm Hg?
a. 64%
b. 74%
c. 85%
d. 95%
ANS: C
DIF: 2 REF: pg. 104
A patient’s baseline arterial blood gas (ABG) reveals a partial pressure of oxygen (PaO2) of 78 mm Hg while receiving 35% supplemental oxygen. What should the ventilator fractional inspired oxygen (FIO2) be set at to obtain a target PaO2 of 95mm Hg?
a. 34%
b. 43%
c. 55%
d. 67%
ANS: B
A patient receiving 60% oxygen from an air entrainment mask has a partial pressure of oxygen (PaO2) of 45 mm Hg. The patient is being intubated and the ventilator set up. What is the appropriate fractional inspired oxygen (FIO2) to achieve a PaO2 of 60 mm Hg?
a. 0.65
b. 0.75
c. 0.8
d. 0.95
ANS: C
The goal of selecting a specific oxygen concentration is to try to achieve clinically acceptable arterial oxygen tensions within which of the following ranges?
a. 40 and 55 mm Hg
b. 50 and 60 mm Hg
c. 60 and 100 mm Hg
d. 100 and 120 mm Hg
ANS: C
The goal of selecting a specific fractional inspired oxygen (FIO2) for a patient is to achieve a clinically acceptable arterial oxygen tension (e.g., 60-100 mm Hg).
Following successful cardiac resuscitation, a patient being placed on mechanical ventilation should have which of the following fractional inspired oxygen (FIO2) settings?
a. 0.5
b. 0.6
c. 0.8
d. 1
ANS: D
Using a high oxygen concentration following a cardiac arrest can provide a way of restoring normal oxygenation and replacing tissue oxygen storage when oxygen debt and lactic acid accumulations occur, as with this patient.
DIF: 3 REF: pg. 104
What is the range for setting flow triggering?
a. 1 to 10 L/min
b. 10 to 15 L/min
c. 12 to 16 L/min
d. 20 to 30 L/min
ANS: A
Flow triggering is set in a range of 1 to 10 L/min below the base flow depending on the selected ventilator.
DIF: 1 REF: pg. 104
A patient is intubated due to an acute exacerbation of Chronic Obstructive Pulmonary Disease (COPD). The patient is now breathing with pressure support ventilation 5 cm H2O and continuous positive airway pressure (CPAP) 5 cm H2O. The patient is unable to flow trigger every inspiration. Unintended positive-end-expiratory pressure (auto-PEEP) is measured at 10 cm H2O. The most appropriate action is to take is which of the following?
a. Decrease the CPAP to 3 cm H2O.
b. Increase the CPAP to 8 cm H2O.
c. Increase pressure support to 10 cm H2O.
d. Change the flow trigger setting to 1 L/min.
ANS: B
Patients may have trouble triggering a breath when unintended positive-end-expiratory pressure (auto-PEEP) is present. When this occurs, adjusting the sensitivity may not alleviate the patient’s inability to trigger the ventilator. When auto-PEEP occurs in mechanically ventilated, spontaneously breathing patients with airflow obstruction, setting extrinsic PEEP to a level equal to about 80% of the patient’s auto-PEEP level may allow the ventilator to sense the patient’s inspiratory efforts. Decreasing the extrinsic PEEP level will not alleviate this problem. Altering the pressure support or the flow trigger will not alleviate this problem.
DIF: 3 REF: pg. 104
How much patient effort is needed to trigger a ventilator breath when there is 8 cm H2O of unintended positive-end-expiratory pressure (auto-PEEP) and a pressure trigger setting of 2 cm H2O?
a. 2 cm H2O
b. 6 cm H2O
c. 8 cm H2O
d. 10 cm H2O
ANS: D
The effort required to trigger a breath equals the sum of the auto-PEEP and the pressure trigger setting.
DIF: 2 REF: pgs. 104-106
A humidifier used with a mechanical ventilator should deliver a minimum of how much humidity?
a. 10 mg H2O/L at 35° C to 37° C
b. 20 mg H2O/L at 31° C to 35° C
c. 30 mg H2O/L at 31° C to 35° C
d. 47 mg H2O/L at 35° C to 37° C
ANS: C
The humidification system used during mechanical ventilation should provide at least 30 mg H2O/L of absolute humidity at a range of about 31° C to 35° C for all available flows up to 20 to 30 L/min.
DIF: 1 REF: pg. 106
Calculate the humidity deficit when a heat moisture exchanger (HME) provided 14 mg/L of water to the set tidal volume.
a. 14 mg/L of water
b. 23 mg/L of water
c. 30 mg/L of water
d. 37 mg/L of water
ANS: C
Humidity deficit = 44 mg/L – absolute humidity
DIF: 2 REF: pgs. 106, 107 (Critical Care Concept 7-1)
In which situation should the heat moisture exchanger (HME) be replaced with a heated humidification system?
a. With all tracheostomy tubes
b. After 3 days of ventilation
c. After 24 hours of ventilation
d. Thick secretions not cleared by suctioning
ANS: D
If secretions appear thick after two consecutive suctioning procedures, the heat moisture exchanger (HME) should be removed and the patient switched to a heated humidification system.
DIF: 2 REF: pg. 107
Following intubation and placement on volume-controlled continuous mandatory ventilation (VC-CMV), a patient’s average peak inspiratory pressure (PIP) is 26 cm H2O following suctioning. The appropriate settings for the low and high pressure alarms are which of the following?
a. Low pressure = 6 cm H2O, high pressure = 46 cm H2O
b. Low pressure = 15 cm H2O, high pressure = 41 cm H2O
c. Low pressure = 20 cm H2O, high pressure = 36 cm H2O
d. Low pressure = 24 cm H2O, high pressure = 31 cm H2O
ANS: C
Low-pressure alarms are usually set about 5 to 10 cm H2O below peak inspiratory pressure (PIP). High-pressure alarms are set about 10 cm H2O above PIP. The only answer that fits both of these criteria is answer “C.”
DIF: 2 REF: pg. 110
A patient is being ventilated with pressure controlled-synchronized intermittent mandatory ventilation (PC-SIMV) of 12 breaths/minute. The apnea alarm time setting should be which of the following?
a. 4 seconds
b. 10 seconds
c. 15 seconds
d. 20 seconds
ANS: B
Apnea alarms are usually set so the patient will not miss two consecutive machine breaths (apnea time > total cycle time [TCT] and
The ventilator volume is set at 575 mL. The low exhaled tidal volume (VT) alarm should be set at which of the following?
a. 150 mL
b. 350 mL
c. 400 mL
d. 500 mL
ANS: D
The low exhaled tidal volume (VT) alarm should be set at 10% to 15% below the set VT.
DIF: 2 REF: pgs. 108, 109
A patient set up on pressure support ventilation (PSV) has an average minute volume of 5.8 L. What should the low exhaled minute volume alarm be set at?
a. 5 L
b. 4 L
c. 3 L
d. 2 L
ANS: A
The low exhaled minute volume alarm should be set between 10% and 15% below the average minute volume.
DIF: 2 REF: pgs. 110, 111