Ventilator mode selection, weaning parameters, and alarm troubleshooting concepts tested on respiratory therapist certification exams.
40 cards · basic cards · AI-written, checked twice. Edit anything.
- What does AC/VC mode stand for in mechanical ventilation?
- Assist/Control, Volume Control. Delivers a set tidal volume with every breath, whether patient-triggered or machine-triggered.
- In PC mode, what parameter is set by the clinician?
- Pressure. The ventilator delivers a set inspiratory pressure; tidal volume varies with lung compliance and resistance.
- What is PSV (Pressure Support Ventilation)?
- A patient-triggered, pressure-limited mode in which the ventilator augments each spontaneous breath with a preset pressure to ease the work of breathing.
- When is SIMV (Synchronized Intermittent Mandatory Ventilation) most commonly used?
- During weaning, to allow gradual transition from machine ventilation to spontaneous breathing while guaranteeing a minimum number of full ventilator-supported breaths.
- What is CPAP (Continuous Positive Airway Pressure)?
- A spontaneous mode that maintains constant positive airway pressure throughout the breathing cycle; no mandatory breaths are delivered.
- What is BiPAP (Bilevel Positive Airway Pressure)?
- A mode that cycles between two pressure levels: a higher pressure during inspiration and a lower pressure during expiration, assisting spontaneous breathing.
- Define the Rapid Shallow Breathing Index (RSBI).
- Respiratory rate divided by tidal volume in liters (f/VT). Values below 100 suggest readiness for weaning; above 100 suggests weaning may fail.
- What is Maximum Inspiratory Pressure (MIP) and what value suggests readiness to wean?
- The most negative airway pressure a patient can generate during inhalation. MIP more negative than -20 cm H2O (or -30 in some protocols) suggests adequate respiratory muscle strength for weaning.
- What is Maximum Expiratory Pressure (MEP) and why is it assessed?
- The most positive airway pressure a patient can generate during exhalation. It reflects expiratory muscle strength and is used to assess cough effectiveness and airway protection.
- What is the significance of a positive Spontaneous Breathing Trial (SBT)?
- The patient tolerates a period of spontaneous breathing (typically on low PSV or CPAP/T-piece for 30-120 minutes) without signs of distress or deterioration, indicating readiness for extubation.
- What are three objective criteria used to assess readiness for weaning?
- 1. Underlying cause of respiratory failure resolved; 2. Adequate oxygenation (PaO2/FiO2 > 200 or SpO2 > 90% on moderate support); 3. Adequate ventilation (pH > 7.25, PaCO2 < 55).
- What does a 'high pressure alarm' on a ventilator usually indicate?
- Obstruction or decreased lung compliance. Causes include secretions, tube obstruction, bronchospasm, pneumothorax, pneumonia, or ventilator malfunction.
- What is the first step when a high pressure alarm sounds on the ventilator?
- Check the patient: assess breath sounds, lung compliance, and tube patency. Listen for crackles, wheezes, or unequal air entry. Suction if needed.
- What causes a 'low pressure alarm' on the ventilator?
- Inadequate circuit pressure. Common causes include ventilator disconnection, endotracheal tube cuff leak, circuit leak, or ventilator malfunction.
- What is the appropriate response to a ventilator disconnect alarm?
- Immediately check the circuit for disconnection. Manually ventilate the patient with a bag-valve-mask if the tube is disconnected, then reconnect or replace the circuit and notify the physician.