CCRN - Review Mechanical Ventilation Management Questions and Answers 1 — Questions and Answers
Question 1: A patient with Acute Respiratory Distress Syndrome (ARDS) is on Assist-Control ventilation. The ventilator's high-pressure alarm sounds. The peak inspiratory pressure (PIP) is 50 cm H2O, and the plateau pressure (Pplat) is 42 cm H2O. Which intervention is the highest priority for the nurse?
- Perform deep endotracheal suctioning.
- Check the ventilator tubing for kinks or water.
- Administer a prescribed bronchodilator.
- Decrease the set tidal volume. (Correct answer)
Correct answer: Decrease the set tidal volume.
A plateau pressure (Pplat) greater than 30 cm H2O indicates decreased lung compliance and places the patient at significant risk for barotrauma or volutrauma. The primary intervention to reduce Pplat and minimize lung injury in ARDS is to decrease the tidal volume, which is a core component of lung-protective ventilation strategy. While the other options address potential causes of increased PIP (airway resistance), the critically high Pplat signifies a problem with alveolar overdistension that must be addressed immediately by reducing the volume delivered.
Question 2: A critical care nurse is managing a patient on Synchronized Intermittent Mandatory Ventilation (SIMV) with a set rate of 12 breaths/minute. The patient's total respiratory rate is 22 breaths/minute. How does the ventilator support the 10 patient-initiated breaths?
- They are delivered with the full set tidal volume.
- They are supported with a set level of pressure support. (Correct answer)
- They receive no support from the ventilator.
- They are delivered with the same inspiratory time as mandatory breaths.
Correct answer: They are supported with a set level of pressure support.
In SIMV mode, the ventilator delivers a set number of mandatory breaths at a specific volume or pressure. Any breaths initiated by the patient above the set rate are spontaneous breaths. These spontaneous breaths are typically supported with a preset level of pressure support to help overcome the resistance of the breathing circuit and reduce the work of breathing, but they do not receive the full mandatory tidal volume.
Question 3: A patient is undergoing a spontaneous breathing trial (SBT) to assess for weaning readiness. Which of the following findings would be the strongest indicator of SBT failure, requiring the patient to be placed back on their previous ventilator settings?
- A heart rate increase from 88 to 105 beats/min.
- A blood pressure change from 120/80 mmHg to 135/88 mmHg.
- A Rapid Shallow Breathing Index (RSBI) of 130 breaths/min/L. (Correct answer)
- A slight increase in patient anxiety noted by the nurse.
Correct answer: A Rapid Shallow Breathing Index (RSBI) of 130 breaths/min/L.
The Rapid Shallow Breathing Index (RSBI), calculated as respiratory frequency divided by tidal volume (f/VT), is a key predictor of weaning success. A value greater than 105 breaths/min/L is highly predictive of weaning failure, indicating that the patient is breathing rapidly and shallowly and cannot sustain the work of breathing. While the other options may be signs of intolerance, an RSBI >105 is a more objective and critical indicator of failure.
Question 4: A patient intubated for a COPD exacerbation has the following arterial blood gas results on volume-controlled ventilation: pH 7.26, PaCO2 68 mmHg, PaO2 88 mmHg, HCO3 29 mEq/L. The current ventilator settings are: Rate 14, Tidal Volume 500 mL, FiO2 0.40, PEEP 5 cm H2O. Which ventilator adjustment is most appropriate to correct the patient's acid-base imbalance?
- Increase the FiO2 to 0.50.
- Increase the respiratory rate to 18. (Correct answer)
- Decrease the tidal volume to 400 mL.
- Increase the PEEP to 8 cm H2O.
Correct answer: Increase the respiratory rate to 18.
The patient's ABG shows uncompensated respiratory acidosis (low pH, high PaCO2). The primary way to correct respiratory acidosis on a ventilator is to increase minute ventilation to facilitate the removal of CO2. Increasing the respiratory rate is a direct and effective way to achieve this. Increasing FiO2 or PEEP would address oxygenation, which is not the primary problem. Decreasing the tidal volume would worsen the hypercapnia.
Question 5: A 70 kg male patient is intubated for ARDS. To adhere to a lung-protective ventilation strategy, the nurse should anticipate setting the initial tidal volume to which of the following ranges?
- 700 - 840 mL (10-12 mL/kg)
- 560 - 700 mL (8-10 mL/kg)
- 280 - 420 mL (4-6 mL/kg) (Correct answer)
- 150 - 250 mL (2-3.5 mL/kg)
Correct answer: 280 - 420 mL (4-6 mL/kg)
The standard of care for ventilating patients with ARDS is a lung-protective strategy that utilizes low tidal volumes to prevent volutrauma and barotrauma. Current evidence and guidelines, such as those from the ARDSNet trials, recommend a tidal volume of 4 to 6 mL per kilogram of *predicted* body weight, not actual body weight, and maintaining a plateau pressure of less than 30 cm H2O.
Question 6: The nurse is caring for a patient on mechanical ventilation when the low-pressure alarm sounds. The nurse assesses the patient and finds them with a decreased level of consciousness and diminished breath sounds on the left side. Which of the following is the most likely cause?
- The patient is biting the endotracheal tube.
- There is a mucus plug in the mainstem bronchus.
- The ventilator tubing has become disconnected from the endotracheal tube. (Correct answer)
- The patient has developed a tension pneumothorax.
Correct answer: The ventilator tubing has become disconnected from the endotracheal tube.
A low-pressure alarm indicates a loss of pressure in the ventilator circuit. The most common cause is a leak or disconnection somewhere between the ventilator and the patient's airway, such as the ventilator tubing becoming disconnected from the endotracheal tube. Mucus plugs, biting the tube, and tension pneumothorax would all cause a HIGH-pressure alarm due to increased resistance or decreased compliance.
CCRN - Review Mechanical Ventilation Management Questions and Answers 1
A patient with Acute Respiratory Distress Syndrome (ARDS) is on Assist-Control ventilation.
The ventilator's high-pressure alarm sounds.
The peak inspiratory pressure (PIP) is 50 cm H2O, and the plateau pressure (Pplat) is 42 cm H2O.
Which intervention is the highest priority for the nurse?