Ventilators & ARDS – Core Vocabulary

Vocabulary flashcards covering key terms, physiology, diagnostic criteria, and therapeutic strategies for ventilator management and ARDS.

Increase PaO₂

by increasing PEEP or FiO₂

Lower PaCO₂

by increasing respiratory rate or tidal volume.

PEEP (Positive End-Expiratory Pressure)

Ventilator setting that prevents alveolar collapse and boosts PaO₂.

FiO₂

Fraction of inspired oxygen; higher values elevate PaO₂.

Tidal Volume (Vₜ)

Volume of air delivered per breath; higher volumes lower PaCO₂ but risk barotrauma.

Respiratory Rate (RR)

Number of breaths per minute set on the ventilator; raising it reduces PaCO₂.

ARDS (Acute Respiratory Distress Syndrome)

Diffuse, non-cardiogenic pulmonary edema causing severe hypoxemia and low compliance.

Berlin Definition (of ARDS)

Criteria including onset ≤1 week, bilateral opacities, non-cardiac origin, and PaO₂/FiO₂ ≤300 with PEEP ≥5 cm H₂O.

P/F Ratio, ARDS classifications

PaO₂ divided by FiO₂ (decimal); classifies ARDS as mild (200-300), moderate (100-200), or severe (<100).

Type I Pneumocytes

Alveolar cells (≈95 %) responsible for gas exchange and structural integrity.

Type II Pneumocytes

Alveolar cells that produce surfactant and can proliferate after injury.

Exudative Phase (ARDS)

First ≤6 days; capillary leak and alveolar edema predominate.

Proliferative Phase (ARDS)

Days 7-14; organization of exudate and beginning of repair.

Fibrotic Phase (ARDS)

14 days; some patients develop permanent fibrotic lung changes.

Low Tidal Volume Ventilation

Lung-protective strategy using 4-8 mL/kg predicted body weight to reduce mortality.

Plateau Pressure

Airway pressure after inhalation pause; goal <30 cm H₂O in ARDS management.

ARDSNet Trial

Landmark study showing low tidal volume and higher PEEP improve mortality and ventilator-free days in ARDS.

Proning

Positioning patient face-down ~17 h/day to improve oxygenation by redistributing ventilation-perfusion.

Neuromuscular Blockade (Paralysis)

Short course of paralytics to improve ventilator synchrony and chest wall compliance in severe ARDS.

ECMO (Extracorporeal Membrane Oxygenation)

Machine oxygenates blood outside body; used as rescue in severe ARDS.

VV ECMO

Venovenous mode providing lung support (oxygenation & CO₂ removal) without cardiac assistance.

VA ECMO

Veno-arterial mode supporting both heart and lungs.

APRV (Airway Pressure Release Ventilation)

Mode delivering prolonged high pressure with brief releases to enhance alveolar recruitment.

High-Frequency Oscillatory Ventilation (HFOV)

Ventilation using very small volumes at rapid rates; limited adult benefit in ARDS.