ICU · Respiratory / ventilation
Airway Pressure Release Ventilation (APRV) and Advanced Ventilation Modes — Comprehensive ICU Management (APRV, Bilevel, PAV, NAVA, ASV)
Also known as Airway pressure release ventilation · APRV · Bilevel ventilation · BiVent · Duo-PAP · Proportional assist ventilation · PAV · Neurally adjusted ventilatory assist · NAVA · Electrical activity of the diaphragm · EAdi · Adaptive support ventilation · ASV · Open lung ventilation · Release ventilation · Advanced ventilator modes
Advanced modes of mechanical ventilation move control away from clinician-set, fixed breaths toward modes that either sustain alveolar recruitment (APRV, bilevel) or proportionalise support to the patient's own effort and neural drive (PAV, NAVA, ASV). Airway pressure release ventilation (APRV) is a pressure-controlled, time-cycled mode that applies a continuous high CPAP (Phigh, set from the plateau or peak inspiratory pressure of the preceding conventional ventilation) held for a long time (Thigh) with brief release periods to a low pressure (Plow 0 cmH2O) for a short time (Tlow ≤0.5 s), allowing spontaneous breathing throughout the cycle. The high mean airway pressure maintains alveolar recruitment and oxygenation (an open-lung strategy), the brief release clears CO2, and the preserved spontaneous breathing reduces sedation, preserves venous return, and protects the diaphragm. Bilevel (BiVent, Duo-PAP) is the generalised two-level mode with set mandatory breaths and a more conventional ratio, giving more control than APRV. Proportional assist ventilation (PAV) amplifies the patient's own inspiratory effort — flow and volume are delivered in proportion to patient demand, requiring an intact respiratory drive. Neurally adjusted ventilatory assist (NAVA) delivers support in proportion to the electrical activity of the diaphragm (EAdi), measured via a specialised nasogastric tube — the most physiological mode, because it directly reads neural respiratory drive and uses it to trigger, cycle, and titrate support. Adaptive support ventilation (ASV) automatically adjusts pressure and rate from moment to moment based on the patient's lung mechanics and respiratory drive, targeting the breathing pattern of minimum work of breathing. Clinically, APRV is used as an open-lung strategy in ARDS with an intact drive, NAVA for the difficult-to-ventilate or dyssynchronous patient, and ASV for stable weaning. The critical, repeatedly-tested evidence point is that NO advanced mode has shown a mortality benefit over conventional volume-controlled or pressure-controlled ventilation in ARDS — the PATIENT and the underlying disease, not the mode, determine outcome — but advanced modes may reduce sedation, dyssynchrony, and delirium.
Practise this topic
On this page
Study tools
Your progress
Saved on this device.
Target exams
Red flags
- No advanced ventilation mode — APRV, bilevel, PAV, NAVA, or ASV — has shown a mortality benefit over conventional volume- or pressure-controlled ventilation in ARDS. The patient and the underlying disease, not the mode, determine outcome.
- APRV is generally AVOIDED in obstructive disease (asthma, COPD) — the sustained high pressure and brief releases risk dynamic hyperinflation and air-trapping, the opposite of the long-expiration strategy these patients need.
- APRV is an open-lung mode for the recruitable, stiff lung — a Phigh set from the preceding plateau pressure, sustained, holds alveoli open and raises mean airway pressure; oxygenation improves but this is a physiological endpoint, not a survival endpoint.
- PAV and NAVA both REQUIRE an intact respiratory drive — they are contra-indicated in the deeply sedated, paralysed, or central-drive-depressed patient, because without patient effort/Edi there is no trigger and no support.
- NAVA depends on correct positioning of the EAdi catheter — a malpositioned catheter reads noise or oesophageal peristalsis rather than diaphragmatic activity, and the support fails or becomes erratic.
- Titrate the APRV release time (Tlow) so expiratory flow returns to 75 per cent of peak — a Tlow too long collapses the lung (derecruitment); a Tlow too short traps gas (dynamic hyperinflation).
Meet the patient
A 52-year-old man with H1N1 pneumonia has been on volume control for 36 hours. Vt 420 mL, PEEP 14, FiO2 0.8 — and the ABG still reads PaO2 62. He is triggering, lightly sedated, RASS −1. The ventilator shows normal-looking waveforms, but the chest X-ray shows bilateral dependent consolidation and the lungs are stiff on the breath. The trainees want to paralyse him. You don't. You want a mode that lets him keep breathing while you keep the lung open.[1]
The single exam question this page answers is: which advanced ventilation mode, in which patient, and to fix what? APRV recruits; NAVA synchronises; PAV amplifies effort; ASV auto-weans. None of them improves mortality on top of lung-protective ventilation — and remembering that is what gets you through the viva.[2]
References15ShowHide
- [1]Putensen C, Mutz NJ, Putensen-Himmer G, Zinserling J. Spontaneous breathing during ventilatory support improves ventilation-perfusion distributions in patients with acute respiratory distress syndrome Am J Respir Crit Care Med, 1999.PMID 10194172
- [2]Patel R, Thompson J, Panchal V, Patel N, Patel V, Iribarren J. Safety, Efficacy, and Clinical Outcomes of APRV in ARDS: A Systematic Review and Meta-Analysis J Intensive Care Med, 2026.PMID 42033378
- [3]Brander L, Leong-Poi H, Beck J, Brunet F, Hutchison SJ, Slutsky AS, Sinderby C. Titration and implementation of neurally adjusted ventilatory assist in critically ill patients Chest, 2009.PMID 19017889
- [4]Tian X, Alizadeh M, Qi H, Shang Y. Application of neurally adjusted ventilatory assist (NAVA): a narrative review J Thorac Dis, 2025.PMID 41229799
- [5]Sklar MC, Patel BK, Beitler JR, Piraino T, Goligher EC. Optimal Ventilator Strategies in Acute Respiratory Distress Syndrome Semin Respir Crit Care Med, 2019.PMID 31060090
- [6]Terragni PP, Del Sorbo L, Mascia L, Urbino R, Martin EL, Birocco A, Faggiano C, Quintel M, Gattinoni L, Ranieri VM. Tidal volume lower than 6 ml/kg enhances lung protection: role of extracorporeal carbon dioxide removal Anesthesiology, 2009.PMID 19741487
- [7]Nieman GF, Bates JHT, Andrews PL, Rose L, Shiber J, Araos J, Aurelien L, Madden M, Manougian T, Satalin J, Varpula T, Al-Khalisy H, Markandaya M, Silva PL, da Fonseca Reis LF, Downs J, Camporota L, Habashi NM. Expert recommendations for setting and adjusting airway pressure release ventilation based on clinical experience and basic science evidence Front Med (Lausanne), 2026.PMID 41709908
- [8]Camporota L, Rose L, Andrews PL, Nieman GF, Habashi NM. Airway pressure release ventilation for lung protection in acute respiratory distress syndrome: an alternative way to recruit the lungs Curr Opin Crit Care, 2024.PMID 38085878
- [9]Nieman GF, Kaczka DW, Andrews PL, Ghosh A, Al-Khalisy H, Camporota L, Satalin J, Herrmann J, Habashi NM. First Stabilize and then Gradually Recruit: A Paradigm Shift in Protective Mechanical Ventilation for Acute Lung Injury J Clin Med, 2023.PMID 37510748
- [10]Kirakli C, Naz I, Ediboglu O, Tatar D, Budak A, Tellioglu E. A randomized controlled trial comparing the ventilation duration between adaptive support ventilation and pressure assist/control ventilation in medical patients in the ICU Chest, 2015.PMID 25742308
- [11]Brower RG, Matthay MA, Morris A, et al. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome N Engl J Med, 2000.PMID 10793162
- [12]Guérin C, Reignier J, Richard JC, Beuret P, Gacouin A, Boulain T, Mercier E, Badet M, Mercat A, Baudin O, Clavel M, Chatellier D, Jaber S, Rosselli S, Mancebo J, Sirodot M, Hilbert G, Bengler C, Richecoeur J, Gainnier M, Bayle F, Bourdin G, Leray V, Girard R, Baboi L, Ayzac L; PROSEVA Study Group. Prone positioning in severe acute respiratory distress syndrome N Engl J Med, 2013.PMID 23688302
- [13]Amato MB, Meade MO, Slutsky AS, Brochard L, Costa EL, Schoenfeld DA, Stewart TE, Briel M, Talmor D, Mercat A, Richard JC, Carvalho CR, Brower RG. Driving pressure and survival in the acute respiratory distress syndrome N Engl J Med, 2015.PMID 25693014
- [14]Habashi NM. Other approaches to open-lung ventilation: airway pressure release ventilation Crit Care Med, 2005.PMID 15753733
- [15]Fajardo-Campoverdi A, Mireles-Cabodevila E, Medina A, Ibarra-Estrada M, Baltazar-Torres J, Chatburn R. Update of the taxonomy of mechanical ventilation modes Med Intensiva, 2025.PMID 40480865