Chapter 20: Weaning and Discontinuation from Mechanical Ventilation

All of the following patients are intubated and receiving mechanical ventilation. Which of them is most likely to require slow liberation from mechanical ventilation?

A patient with chest contusions from a motor vehicle crash

A patient is being weaned from invasive mechanical ventilation using VC-IMV. The respiratory therapist reviews the following data from the past few hours

Add and titrate pressure support

What ends inspiration in pressure support ventilation?

Flow

At what pressure is pressure support not high enough to contribute significantly to ventilatory support but is sufficient to overcome the work imposed by the ventilator system?

5 cm H2O

Which mode of ventilation delivers the exact amount of pressure required to overcome the resistive load imposed by the ET tube for the flow measured at the time?

Automatic tube compensation

What mode of ventilation maintains a minimum VE by increasing or decreasing the amount of support (VT or respiratory rate) given to the patient?

Mandatory minute ventilation

Which of the following is considered a closed loop mode used for weaning from mechanical ventilation?

Adaptive support ventilation

A postoperative patient, still under anesthesia, is being ventilated with VC-CMV with automode. After 2 hours, the patient is waking up and beginning to breathe spontaneously. How will the ventilator respond?

By switching to the volume support mode

The ACCP/SCCM/AARC task force recommends that a search for all possible causes that may be contributing to ventilator dependence be undertaken in patients who require mechanical ventilation for longer than how many hours?

24

Assess the following data obtained from the spontaneous breathing trials of four patients. Which patient is most likely to be weaned successfully at this time?

Spontaneous rate = 15 breaths/min, VT = 650 mL, PaO2 = 91 mm Hg, FIO2 = 0.28

A 46-year-old male patient (IBW = 85 kg) who was injured in a motor vehicle crash has been receiving invasive mechanical ventilation for 24 hours. The patient is awake, alert, and looks comfortable on the following settings: VC-IMV with pressure support of 5 cm H2O; set rate = 8 breaths/min; set VT = 500 mL; FIO2 = 0.4; PEEP = 5 cm H2O. A 10-minute spontaneous breathing trial (SBT) yields this information: f = 30 breaths/min, RSBI = 145, P0.1 = 10 cm H2O. What should the respiratory therapist suggest to the physician during patient rounds?

Continue with the current ventilator settings

Calculate and determine the weanability of patients with this data: CD = 25 mL/cm H2O, PImax = 28 cm H2O, PaO2 = 93 mm Hg, PAO2 = 158 mm Hg, and f = 22 breaths/min.

19—weanable

Which parameter is used as the primary index of the drive to breathe?

Airway occlusion pressure

What is the longest time an SBT should last?

120 minutes

In which patient would continued use of an artificial airway likely be necessary?

A patient with upper airway burns and no peritubular leak

A recently extubated patient develops a partial upper airway obstruction, which causes stridor. What action can the respiratory therapist take to improve the patient's condition?

Nebulize racemic epinephrine (0.5 mL, 2.25% epinephrine in 3 mL normal saline)

A female intubated patient has been weaned from full ventilatory support to PSV 5 cm H2O, CPAP 5 cm H2O, and an FIO2 of 0.3. The patient is alert and oriented and doing well. The respiratory therapist performs a cuff leak test. The average peritubular leak is 70 mL. The respiratory therapist should recommend which of the following?

Pretreat the patient with steroids and/or racemic epinephrine before extubation.

A patient is extubated and placed on a cool, bland aerosol with 30% oxygen. Twenty minutes post extubation, the respiratory therapist is called to assess the patient, who has shortness of breath. The respiratory therapist observes intercostal retractions, accessory muscle use, and a respiratory rate of 38 breaths/min. Stridor can be heard without a stethoscope, and the SpO2 has dropped from 97% to 85%. The patient is given an aerosolized racemic epinephrine treatment and reassessed. Accessory muscle use continues, intercostal retractions decrease slightly, and stridor is heard on auscultation. The patient's respiratory rate is 30 breaths/min and the SpO2 is 88%. What should the respiratory therapist recommend?

Heliox therapy and steroid administration

If a patient who has failed an SBT still meets the criteria for discontinuation of ventilation, when should an SBT should be performed to determine weanability?

Every 24 hours

Sixty minutes after a patient is extubated, an arterial blood gas sample is drawn; the results are: pH = 7.20, PaCO2 = 60 mm Hg, PaO2 = 55 mm Hg, SaO2 = 80%, HCO3 = 23 mEq/L with a 2 L/min nasal cannula. The patient is SOB and complaining of chest pain. His blood pressure is 92/50 mm Hg. The most likely cause of this weaning failure is which of the following?

Acute left ventricular failure

How long does a tracheostomy site typically take to mature?

7-10 days

After all weaning attempts during that time have failed, a patient who requires prolonged ventilatory support should be considered permanently ventilator dependent after how many months?

3

A patient being actively weaned from mechanical ventilation currently is receiving the following ventilatory support: pressure support = 15 cm H2O, spontaneous VT = 575 mL, spontaneous rate = 14 breaths/min, spontaneous VT = 500 mL, FIO2 = 35%, PEEP = 5 cm H2O. The arterial blood gas results are: pH = 7.42, PaCO2 = 38 mm Hg, PaO2 = 94 mm Hg, SaO2 = 98%, HCO3 - = 24 mEq/L. What should the respiratory therapist do next?

Reduce the PS to 10 cm H2O

Which of the following would suggest that a patient is ready to be weaned from a ventilator?

Rapid shallow breathing index of 75 breaths/min/L

A patient in the ICU who has successfully completed a 120-minute SBT requires extubation. Which of the following tests or values would indicate the potential for airway edema after extubation?

Cuff leak test

A patient with amyotrophic lateral sclerosis has a tracheostomy tube in place. He has been unable to perform an SBT successfully and has been receiving mechanical ventilation for 4 months. An appropriate recommendation for this patient might be which of the following?

1. Transfer to a long-term care facility

2. Evaluation for the use of noninvasive ventilation (NIV)

3. Termination of ventilation

4. Waiting until the primary cause of respiratory failure has been resolved

1,2

When weaning is unsuccessful for a patient who successfully performs an SBT, which of the following factors should be assessed?

1. Cardiac factors

2. Nutritional status and respiratory muscle strength

3. Acid-base status

4. Psychological factors

1,2,3,4

Which of the following drugs is used most often to treat postextubation glottic edema?

A. Racemic epinephrine

B. Intravenous steroids

C. Albuterol via metered-dose inhaler

D. Cromolyn sodium

Racemic epinephrine

Which of the following statements is true?

A. In 1MV, all breaths are spontaneously triggered.

B. In the A/C mode, every patient effort delivers the set VT•

C. In IMV, all breaths deliver the same VT.

D. PS can be used to augment the VT in A/C.

In the A/C mode, every patient effort delivers the set VT•

Which of the following should be required before an SBT?

1. The patient should be given a sedative.

2. The patient should be able to maintain an adequate Pa02 and PaC02 during spontaneous breathing.

3. The patient should be hemodynamically stable.

4. The patient's Plmax should be 50 mm Hg.

2,3

Which of the following modes of mechanical ventilation automatically adjusts ventilatory parameters based on continuous monitoring of compliance and airway resistance?

1. Proportional assist ventilation

2. Pressure-regulated volume control

3. Adaptive support ventilation

4. Airway pressure release ventilation

1,3

Which of the following would indicate a successful weaning trial and extubation?

1. Pa02 80 mm Hg on F102 0.4

2. Pa02/F102 ratio 150 to 200 mm Hg

3. Dopamine greater than 5 mg/kg/min to maintain blood pressure

4. pH 7.38

1,4