Chart — Mechanical Ventilation
Ventilator Modes Comparison Chart
Every mode is a trade between what you guarantee and what you let float. This chart lines the common modes up by what you set, what varies, whether minute ventilation is protected, and the failure mode to watch for at the bedside.
Written by Apex Respiratory Editorial Team
Educational use only. This material supports respiratory therapy education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional protocols, or physician orders. Always follow facility policies and current provider orders, and verify calculations independently before clinical use.
Common Modes Side by Side
| Mode | What You Set | What Varies | Guaranteed V̇E? | Spontaneous Effort | Typical Use | Watch For |
|---|---|---|---|---|---|---|
| AC/VC | Rate, VT, flow, PEEP, FiO₂ | PIP varies | Yes (minimum) | Every trigger = full VT | Most initiations | Alkalosis with tachypnea, breath stacking, high PIP |
| AC/PC | Rate, inspiratory pressure, I-time | VT varies with mechanics | No | Every trigger = full pressure breath | Injured / stiff lungs, pressure ceilings | Falling VT as compliance worsens |
| SIMV ± PS | Mandatory rate + VT or pressure; PS level | Spontaneous VT varies | Partial | Yes, between mandatory breaths | Historical weaning, some post-op | Higher work of breathing at low rates |
| PSV | PS level, PEEP, FiO₂ | Rate, VT, I-time all patient | No | All breaths spontaneous | SBTs, comfort on light support | Apnea — needs a backup |
| PRVC | Target VT, rate, max pressure | Delivered pressure adapts | Yes (targeted) | Yes | Dual-control default in some ICUs | Rising pressures flag worsening mechanics |
| APRV | P-high, P-low, T-high, T-low | Release VT varies | No | Breathes throughout | Refractory hypoxemia per institution | Volutrauma in releases, deflation issues |
| CPAP | One pressure | Everything else patient | No | All spontaneous | OSA, oxygenation support, SBT | No ventilation support |
Clinical Notes
The whole table reduces to one decision: what do you want to guarantee? Volume-control modes lock the tidal volume and let pressure float, so you protect minute ventilation but must watch peak and plateau pressures. Pressure-control modes lock the pressure and let tidal volume float, so you protect the lung from barotrauma but must watch for falling V̇E as compliance changes.
- Guaranteed V̇Emeans a protected minute ventilation. Modes that do not guarantee it — PSV, CPAP, APRV — depend on the patient’s own drive and need an apnea backup.
- Dual-control modes like PRVC try to give you both: you target a volume and the ventilator adjusts pressure breath to breath. Rising delivered pressure is an early warning that mechanics are worsening.
- Match the mode to the goal. Full support for an apneic or unstable patient, lighter spontaneous modes for weaning and spontaneous breathing trials. Always confirm an alarm and backup strategy fits the mode you choose.
Related Resources
Sources
- Kacmarek RM, Stoller JK, Heuer AJ. Egan's Fundamentals of Respiratory Care. 12th ed. Elsevier; 2021. Mechanical ventilation chapters.
- Chatburn RL, El-Khatib M, Mireles-Cabodevila E. A taxonomy for mechanical ventilation: 10 fundamental maxims. Respir Care. 2014;59(11):1747-1763.