Deck 12: Methods to Improve Ventilation in Patient-Ventilator Management

Question 1

A male patient (83-kg IBW)is intubated and ventilated with PC-CMV,f = 12/min,set PIP = 28 cm H₂O,resulting in a Vᴛ of 430 mL.The ABG results on this setting are: pH 7.35,PₐCO₂ 45 mm Hg,and HCO₃⁻ 23 mEq/L.Forty-eight hours later on the same settings,the ABG results are: pH 7.54,PₐCO₂ 27 mm Hg,and HCO₃⁻ 21 mEq/L with an exhaled Vᴛ of 800 mL.The most appropriate action at this time is which of the following?

A) Decrease PIP to 25 cm H₂O.
B) Decrease PIP to 19 cm H₂O.
C) Decrease f to 10/min.
D) Decrease f to 8/min.

Answer 1

B
At first the patient responded appropriately to the PC-CMV settings.At that point the Cₛ was 15 mL/cm H₂O.After 48 hours,the patient's lungs improved and the same pressure,28 cm H₂O,resulted in a Vᴛ of 800 mL.The patient's Cₛ now is 28.5 mL/cm H₂O,and the combination of Cₛ and PIP is resulting in respiratory alkalosis.The acceptable Vᴛ range for this patient is 415-664 mL (5-8 mL/kg IBW).Because the exhaled tidal volume now exceeds this range,the volume needs to be reduced.This is accomplished by reducing the set PIP using the following formulas:
Desired Vᴛ = and set PIP = Vᴛ/Cₛ = 19 cm H₂O.

Question 2

In which of the following situations should iatrogenic hyperventilation be considered?

A) Severe traumatic brain injury
B) Initial treatment for increased intracranial pressure
C) Acute head injuries with increased intracranial pressure
D) Acute neurological deterioration with increased intracranial pressure

Answer 2

D
Hyperventilation may be needed for brief periods when acute neurological deterioration is present and the ICP is elevated.Current therapeutic guidelines for head injuries with increased ICP do not recommend prophylactic hyperventilation (PₐCO₂ < 25 mm Hg)during the first 24 hours.Hyperventilation during the first few days after severe traumatic brain injury (TBI)may actually increase cerebral ischemia and cause cerebral hypoxemia.

Question 3

Permissive hypercapnia could benefit patients with which of the following?

A) Cerebral trauma
B) Intracranial lesion
C) Acute lung injury
D) Cardiovascular instability

Answer 3

C
Patients with ALI benefit from permissive hypercapnia to protect the lungs from ventilator-induced lung injury.Contraindications to PHY include cerebral disorders,because CO₂ is a powerful vasodilator.PHY is also contraindicated in patients with preexisting cardiovascular instability,because the circulatory effects of PHY can include decreased myocardial contractility,arrhythmias,vasodilation,and increased sympathetic activity.

Question 4

A patient with an IBW of 68 kg is intubated and being mechanically ventilated with VC-CMV,f = 12/min,and Vᴛ = 470 mL.The patient has a combined respiratory rate of 25/min.The ABG results are: pH 7.56,PₐCO₂ 26 mm Hg,and HCO₃⁻ 22 mEq/L.The most appropriate action is to do which of the following?

A) Decrease the set f to 8/min.
B) Decrease the set Vᴛ to 300 mL.
C) Sedate and paralyze the patient.
D) Change the mode to VC-IMV.

Question 5

At what point during deep suctioning should negative pressure be applied?

A) Five seconds after resistance is met
B) Ten seconds after insertion of the catheter
C) After 1-cm withdrawal from the point of resistance
D) After 2-cm withdrawal from the point of resistance

Question 6

A female patient (59-kg IBW)with no history of pulmonary disease is being invasively ventilated with VC-CMV,f = 12/min,Vᴛ = 470 mL,PEEP = 5 cm H₂O,FɪO₂ = 0.5.ABG results with these settings are: pH 7.31,PₐCO₂ 54 mm Hg,PₐO₂ 92 mm Hg,SₐO₂ 90%,HCO₃⁻ 24 mEq/L.The most appropriate action for the respiratory therapist to take is which of the following?

A) Increase f to 16/min.
B) Increase Vᴛ to 635 mL.
C) Decrease Vᴛ to 400 mL.
D) Decrease PEEP to 3 cm H₂O.

Question 7

A 28-year-old female (55-kg IBW)is being mechanically ventilated with VC-CMV,f = 14/min,Vᴛ = 700 mL.The patient has no history of pulmonary disease.The resulting ABG values are: pH 7.55,PₐCO₂ 27 mm Hg,HCO₃⁻ 23 mEq/L.The most appropriate action to take is which of the following?

A) Decrease Vᴛ to 600 mL.
B) Decrease Vᴛ to 450 mL.
C) Decrease f to 12/min.
D) Decrease f to 10/min.

Question 8

A male patient (74-kg IBW)is being ventilated with PC-CMV,f = 12/min,PIP = 20 cm H₂O,TI = 1.5 seconds; the resulting flow-time scalar is shown below.The patient's measured Vᴛ is 435 mL.ABG results on these settings are: pH 7.32,PₐCO₂ 54 mm Hg,HCO₃⁻ 25 mEq/L.The most appropriate action to take is which of the following?

A) Increase f to 16/min.
B) Increase TI to 2.5 sec.
C) Increase PIP to 27 cm H₂O.
D) Decrease flow rate to 40 L/min.

Question 9

A patient with CHF is being mechanically ventilated.The patient's current PₐCO₂ = 28 mm Hg,and the ventilator set rate is 16 per minute.The desired PₐCO₂ for this patient is 40 mm Hg.To what should the set rate be changed?

A) 7/min
B) 11/min
C) 14/min
D) 18/min

Question 10

The average tidal volume range in an individual with no pulmonary problems is which of the following?

A) 4⁻⁵ mL/kg IBW
B) 5-8 mL/kg IBW
C) 8-10 mL/kg IBW
D) 12-15 mL/kg IBW

Question 11

Which of the following can cause metabolic acidosis?

A) Overdose with salicylate
B) Diuretic administration
C) Nasogastric suctioning
D) Lactate administration

Question 12

If respiratory acidosis persists after alveolar ventilation of a patient has been increased,which of the following could be the cause?

A) Chronic obstructive pulmonary disease
B) Pulmonary embolism
C) Pulmonary edema
D) Low PEEP levels

Question 13

A patient with pneumonia and underlying COPD is being mechanically ventilated in the VC-CMV mode with Vᴛ 650 mL.The resulting PₐCO₂ is 62 mm Hg.What change should be made to the Vᴛ to obtain a desired PₐCO₂ of 50 mm Hg for this patient?

A) 400 mL
B) 800 mL
C) 1000 mL
D) 1200 mL

Question 14

Which of the following can cause metabolic alkalosis?

A) Renal failure
B) Potassium deficiency
C) Carbonic anhydrase inhibitors
D) Ethylene glycol

Question 15

A suction catheter long enough to reach a mainstem bronchus should be what length?

A) 22 cm (8.7 inches)
B) 25 cm (9.8 inches)
C) 46 cm (18 inches)
D) 56 cm (22 inches)

Question 16

A male patient (76-kg IBW)with no history of pulmonary disease is brought to the emergency department for treatment of a drug overdose.He is intubated and placed on mechanical ventilation with VC-CMV,f = 12/min,Vᴛ = 450 mL.The resulting arterial blood gas values are: pH 7.32,PₐCO₂ 53 mm Hg,and HCO₃⁻ 25 mEq/L.The most appropriate action to correct the acid-base disturbance is which of the following?

A) Increase Vᴛ to 595 mL.
B) Increase Vᴛ to 760 mL.
C) Increase frequency to 16/min.
D) Decrease frequency to 10/min.

Question 17

A patient diagnosed with sepsis who is being mechanically ventilated has a combined minute ventilation of 25 L/min with a PₐCO₂ of 38 mm Hg.The reason for these findings is most likely which of the following?
1)Increased CO₂
2)Decreased CO₂
3)Increased VD/Vᴛ
4)Decreased VD/Vᴛ

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

Question 18

A 45-year-old female (58-kg IBW)with a past medical history of asthma arrives at the emergency department short of breath,anxious,diaphoretic,and unable to perform a peak expiratory flow measurement.She also has a combined acidosis.Breath sounds reveal the patient is not moving much air.The patient is intubated,stabilized,and transported to the ICU.The ventilator settings are: PC-CMV,f = 12/min,PIP = 30 cm H₂O,FɪO₂ = 0.6,and PEEP = 3 cm H₂O.The patient is sedated and paralyzed; the resulting ABGs are: pH 7.17,PₐCO₂ 69.3 mm Hg,PₐO₂ 90 mm Hg,and HCO₃⁻ 21 mEq/L after continuous bronchodilator therapy.The respiratory rate is increased to 20/min,and the next ABG results are: pH 7.26,PₐCO₂ 58 mm Hg,PₐO₂ 96 mm Hg,and HCO₃⁻ 22 mEq/L.The respiratory therapist should suggest which of the following at this time?

A) Increase PIP to 38 cm H₂O.
B) Decrease PIP to 25 cm H₂O.
C) Continue with current therapy.
D) Change to VC-CMV, f = 12/min, Vᴛ = 700 mL.

Question 19

A 59-kg IBW female patient is being mechanically ventilated in the CMV mode,f = 12/min,Vᴛ = 400 mL,PEEP = 5 cm H₂O,FɪO₂ = 0.5.The ABG results on these settings show a respiratory acidosis and severe hypoxemia.The respiratory therapist increases the set Vᴛ and increases the PEEP to 12 cm H₂O.The resulting ABGs show improved oxygenation,but the patient still has a respiratory acidosis.The respiratory acidosis may be due to which of the following?

A) Tissue hypoxia
B) Increased dead space
C) Increased cardiac output
D) Continued hypoventilation

Question 20

During mechanical ventilation of a patient with COPD,the PₐCO₂ = 58 mm Hg and the minute ventilation = 5.5 L/min.The desired PₐCO₂ for this patient is 45 mm Hg.To what should the minute ventilation be changed?

A) 4.3 L/min
B) 4.8 L/min
C) 6.6 L/min
D) 7.1 L/min

Question 21

What size suction catheter is appropriate for use in a patient with a 7-mm ET tube?

A) 8 Fr
B) 10 Fr
C) 12 Fr
D) 14 Fr

Question 22

During a closed suctioning procedure,the patient's heart rate changes from 95 to 58 beats/min.The respiratory therapist should take what immediate action?

A) Continue the procedure until secretions are removed.
B) Stop the procedure and switch to the open suctioning method.
C) Stop the procedure and use the ventilator to hyperoxygenate the patient with 100% oxygen.
D) Remove the patient from the ventilator and ventilate the person with a resuscitator bag.

Question 23

Advantages of closed suctioning include which of the following?
1)No need to prehyperoxygenate or posthyperoxygenate.
2)No need to prehyperventilate or posthyperventilate.
3)Decreased risk of infection for caregiver.
4)No loss of PEEP during the procedure.

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

Question 24

Which of the following is the normal ratio of dead space to tidal volume (VD/Vᴛ)?

A) 0.2-0.4
B) 0.4-0.6
C) 0.6-0.8
D) 0.8-1.0

Question 25

Which of the following ventilator graphics could be used to assess the response to bronchodilator therapy for a patient receiving mechanical ventilation with VC-CMV?
1)Pressure-time scalar
2)Flow-time scalar
3)Pressure-volume loop
4)Volume-time scalar

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

Question 26

A mechanically ventilated patient continues to have rhonchi after deep suctioning.The respiratory therapist should recommend which of the following?

A) Prone position
B) Vest Airway Clearance System
C) Prone position with the foot of the bed elevated 12 inches
D) Supine position with the foot of the bed elevated 18 inches

Question 27

An invasively ventilated patient with ARDS is on PC-CMV,PIP = 30 cm H₂O,PEEP = 12 cm H₂O,FɪO₂ = 1.0.The patient's returned Vᴛ is 320 mL.The ABG results on these settings are: pH 7.3,PₐCO₂ 53 mm Hg,PₐO₂ 62 mm Hg.The patient is placed in the prone position,and after 1 hour,ABG results show: pH 7.38,PₐCO₂ 46 mm Hg,PₐO₂ 83 mm Hg.The respiratory therapist should do which of the following?

A) Keep the patient in the prone position.
B) Place the patient in the supine position.
C) Keep the patient in the prone position and decrease the FɪO₂.
D) Place the patient in the supine position and decrease PEEP.

Question 28

What effect does positive-pressure ventilation have on fluid balance?

A) It increases urinary output.
B) It increases renal perfusion.
C) It causes renal malfunction.
D) It increases plasma ADH levels.

Question 29

Common causes of respiratory alkalosis include which of the following?
1)Mechanical ventilation
2)Anxiety
3)Hyperventilation
4)Parenchymal lung disease

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

Question 30

Which of the following is recommended when administering aerosols to mechanically ventilated patients with a small-volume nebulizer?

A) Make sure the flow-by is turned on during administration.
B) Keep the HME in-line during the aerosol treatment.
C) Use the ventilator nebulizer system when appropriate.
D) Bypass the humidifier during the aerosol treatment.

Question 31

When using an SVN or pMDI with NPPV,where in the NPPV circuit should the device be placed to obtain the greatest aerosol deposition?

A) Before the leak port
B) Anywhere in the circuit
C) Between the NPPV and the humidifier
D) Between the leak port and the face mask

Question 32

A physician and a respiratory therapist are performing bedside bronchoscopy of an invasively ventilated patient.Fentanyl and midazolam were used for conscious sedation.After the bronchoscopy,the patient is not arousable.Which of the following should be done at this time?

A) DRₐᴡa sample for arterial blood gas determinations.
B) Increase the patient's respiratory rate.
C) Administer naloxone.
D) Administer atropine.