Ventilator Modes Guide
What Are Ventilator Modes?
Ventilator modes are different ways mechanical ventilators deliver breaths to patients who need respiratory support. Each mode has specific characteristics that determine how the ventilator initiates, delivers, and cycles breaths.
Understanding ventilator modes is fundamental for respiratory therapists, as mode selection impacts patient comfort, work of breathing, and clinical outcomes.
Pressure vs Volume Ventilation
Volume-Controlled Ventilation
In volume-controlled modes, the ventilator delivers a set tidal volume with each breath. The pressure required to deliver that volume varies based on lung compliance and resistance.
- Guarantees consistent tidal volume delivery
- Pressure varies with changes in lung mechanics
- Commonly used in many clinical situations
Pressure-Controlled Ventilation
In pressure-controlled modes, the ventilator delivers breaths to a target pressure. The tidal volume delivered varies based on lung compliance and resistance.
- Maintains consistent airway pressure
- Tidal volume varies with changes in lung mechanics
- May improve patient-ventilator synchrony
Common Mode Categories
Assist-Control (AC) Modes
The ventilator delivers a full breath for every patient effort, plus mandatory breaths if the patient doesn't initiate one within a set time.
Synchronized Intermittent Mandatory Ventilation (SIMV)
Delivers mandatory breaths at set intervals while allowing spontaneous breaths between them. Spontaneous breaths may or may not be supported.
Pressure Support Ventilation (PSV)
A spontaneous mode that assists patient-initiated breaths with a set pressure level. All breaths are triggered by the patient.
Continuous Positive Airway Pressure (CPAP)
Maintains a constant positive pressure throughout the respiratory cycle while the patient breathes spontaneously.
Key Concepts in Mode Selection
Trigger: What initiates a breath (time, patient effort, or both)
Limit: What is controlled during breath delivery (pressure or flow)
Cycle: What ends inspiration (time, volume, or flow)
Baseline: The pressure maintained at end-expiration (PEEP)
Advanced and Specialty Modes
Modern ventilators offer numerous advanced modes designed for specific clinical situations. These may include adaptive modes, dual-control modes, and lung-protective strategies.
Each ventilator manufacturer may use different names for similar concepts, making it important to understand the underlying principles rather than just mode names.
Need Deeper Clinical Application?
RTB2 provides comprehensive breakdowns of ventilator modes with clinical context, real-world application guidance, and quick reference tools designed for respiratory therapists at the point of care.
Educational Disclaimer: This content is for educational purposes only and not a substitute for clinical judgment or institutional protocols. Always follow your facility's policies and current evidence-based guidelines when selecting and managing ventilator modes.