FFICM Respiratory Management and Mechanical Ventilation 1 — Questions and Answers
Question 1: According to the ARDSNet protocol, what tidal volume is recommended for lung-protective ventilation in ARDS?
- 6 ml/kg predicted body weight (Correct answer)
- 10 ml/kg actual body weight
- 8 ml/kg ideal body weight
- 12 ml/kg predicted body weight
Correct answer: 6 ml/kg predicted body weight
The ARDSNet protocol recommends 6 ml/kg predicted body weight, reducible to 4 ml/kg if needed to keep plateau pressure ≤30 cmH2O.
Question 2: What is the target plateau pressure in lung-protective ventilation to minimize ventilator-induced lung injury?
- ≤30 cmH2O (Correct answer)
- ≤40 cmH2O
- ≤20 cmH2O
- ≤50 cmH2O
Correct answer: ≤30 cmH2O
A plateau pressure ≤30 cmH2O is the ARDSNet target to reduce barotrauma and volutrauma in ARDS.
Question 3: In pressure-controlled ventilation (PCV), which parameter is directly set by the clinician?
- Inspiratory pressure above PEEP (Correct answer)
- Tidal volume delivered
- Peak expiratory flow rate
- Mean airway pressure
Correct answer: Inspiratory pressure above PEEP
In PCV the clinician sets the inspiratory pressure; the resulting tidal volume varies with lung compliance and resistance.
Question 4: What is the primary physiological purpose of applying PEEP in mechanically ventilated patients with ARDS?
- Prevent alveolar derecruitment and improve oxygenation (Correct answer)
- Reduce the patient's inspiratory effort
- Decrease inspiratory time and improve CO2 clearance
- Lower peak airway pressures by reducing flow
Correct answer: Prevent alveolar derecruitment and improve oxygenation
PEEP maintains alveolar patency at end-expiration, preventing cyclic collapse-reopening injury and improving V/Q matching.
Question 5: Which ventilator mode delivers mandatory breaths at a minimum set rate while allowing the patient to trigger additional spontaneous breaths?
- Synchronized Intermittent Mandatory Ventilation (SIMV) (Correct answer)
- Continuous Positive Airway Pressure (CPAP)
- Assist-Control Ventilation (ACV)
- Airway Pressure Release Ventilation (APRV)
Correct answer: Synchronized Intermittent Mandatory Ventilation (SIMV)
SIMV synchronizes mandatory breaths with patient effort and permits unsupported spontaneous breaths between them, facilitating gradual weaning.
Question 6: Patient Self-Inflicted Lung Injury (P-SILI) in spontaneously breathing patients primarily results from:
- Excessive respiratory effort generating injurious transpulmonary pressure swings (Correct answer)
- Positive pressure delivered by the ventilator during inspiration
- Barotrauma from high set PEEP levels
- Secretion retention causing focal atelectasis
Correct answer: Excessive respiratory effort generating injurious transpulmonary pressure swings
In P-SILI, vigorous inspiratory effort creates large negative pleural pressure swings that amplify transpulmonary pressure, causing lung injury even without invasive ventilation.
Question 7: In volume-controlled ventilation (VCV), which parameter varies in response to changes in respiratory system compliance?
- Peak airway pressure (Correct answer)
- Delivered tidal volume
- Set respiratory rate
- Inspiratory flow waveform
Correct answer: Peak airway pressure
In VCV the tidal volume is fixed; changes in compliance or resistance are reflected as changes in peak (and plateau) airway pressure.
FFICM Respiratory Management and Mechanical Ventilation 1
According to the ARDSNet protocol, what tidal volume is recommended for lung-protective ventilation in ARDS?