CBET Ventilators and Respiratory Therapy Equipment

Question 1

A ventilator is set to Volume-Controlled Ventilation (VCV) at 500 mL tidal volume.
The high peak pressure alarm activates with every breath.
Plateau pressure measured during an inspiratory hold is normal.
What is the most likely cause?

Accepted Answer

Increased airway resistance (e.g., bronchospasm or secretions)

Answer

Decreased lung compliance (stiff lungs)

Answer

Auto-PEEP from insufficient expiratory time

Answer

A leak in the ventilator circuit

Question 2

What is the primary physiological purpose of Positive End-Expiratory Pressure (PEEP) in a mechanically ventilated patient?

Accepted Answer

To prevent alveolar collapse (atelectasis) at end-expiration and improve oxygenation

Answer

To increase minute ventilation by extending inspiratory time

Answer

To reduce the work of breathing by lowering peak inspiratory pressure

Answer

To deliver supplemental oxygen above the set FiO₂

Question 3

During annual PM on a mechanical ventilator, which test is MOST critical for patient safety regarding oxygen delivery?

Accepted Answer

Calibration and accuracy check of the oxygen sensor/analyzer

Answer

Verification of the humidifier thermostat accuracy

Answer

Testing the exhalation valve seal

Answer

Measuring peak inspiratory flow rate

Question 4

In Pressure-Controlled Ventilation (PCV), what variable is directly set by the clinician and remains constant despite changes in the patient's lung mechanics?

Accepted Answer

Inspiratory pressure above PEEP

Answer

Tidal volume delivered

Answer

Peak inspiratory flow rate

Answer

Minute ventilation

Question 5

A ventilator's continuous high-pressure alarm is sounding. The patient is stable on manual (bag) ventilation. After checking for obvious circuit kinks and confirming the ETT is not kinked, what should the BMET check next on the ventilator itself?

Accepted Answer

The exhalation valve for sticking or obstruction

Answer

The flow trigger sensitivity setting

Answer

The inspiratory filter for occlusion

Answer

The PEEP valve spring tension

Question 6

What is the primary purpose of a heated wire ventilator circuit compared to a standard circuit?

Accepted Answer

To prevent rainout (condensation) in the circuit tubing by keeping temperature above the dew point

Answer

To reduce the internal diameter of the circuit to increase flow velocity

Answer

To sterilize inspired gas before delivery to the patient

Answer

To measure inspiratory temperature for feedback control of FiO₂