• Peak vs. Plateau Pressures: PIP reflects total airway resistance and compliance, while Pplat isolates alveolar compliance—elevations in both suggest decreased lung compliance (e.g., ARDS, pulmonary edema, pneumothorax).
• PEEP Protects Alveoli: Maintains alveolar recruitment and prevents collapse; typical range 5–8 cmH₂O, but higher levels may benefit moderate–severe ARDS.
• Driving Pressure (ΔP = Pplat − PEEP): Lower ΔP reduces atelectrauma and improves outcomes; optimize by adjusting PEEP thoughtfully.
• Prevent VILI: Keep Pplat < 30 cmH₂O, use low tidal volumes (6 mL/kg IBW), and monitor for barotrauma, volutrauma, atelectrauma, and biotrauma.
• Evidence-Based Practice: ARDSNet and subsequent trials confirm that lung-protective ventilation—low Vt, limited pressures, and individualized PEEP—improves survival in ARDS.

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This episode reviews essential ventilator pressures and how to interpret them during ICU rounds.

1. Peak Inspiratory Pressure (PIP)
   • Definition: Total pressure required to deliver a breath.
   • Reflects: Airway resistance + lung/chest wall compliance.
   • Common Causes of ↑ PIP:
     • Mucus plugging
     • Biting the endotracheal tube
     • Kinked tubing or bronchospasm
2. Plateau Pressure (Pplat)
   • Definition: Alveolar pressure measured after an inspiratory hold.
   • Reflects: Lung compliance (stiffness of lung tissue).
   • When Both PIP & Pplat Are Elevated:
     → Indicates poor compliance (e.g., ARDS, pulmonary edema, pneumothorax).
3. Positive End-Expiratory Pressure (PEEP)
   • Definition: Pressure remaining in airways at end-expiration to prevent alveolar collapse.
   • Typical Range: 5–8 cmH₂O but needs to titrated to meet patient requirements 
   • Notes:
     • Provides physiologic “glottic” PEEP in intubated patients.
     • Using high PEEP strategy shows mortality benefit only in moderate–severe ARDS in meta-analysis.
4. Driving Pressure (ΔP)
   • Definition: ΔP = Pplat − PEEP.
   • Reflects: Pressure needed to keep alveoli open during the respiratory cycle.
   • Goal: Lower ΔP → less atelectrauma & improved outcomes.
   • Optimize: Increase PEEP to reduce ΔP and alveolar cycling.

• ↑ PIP & ↑ Pplat
  • Interpretation: ↓ Compliance
  • Common Causes: ARDS, pulmonary edema, pleural effusion, pneumothorax
• ↑ PIP & Normal/Low Pplat
  • Interpretation: ↑ Airway Resistance
  • Common Causes: Mucus plug, bronchospasm, tube obstruction or biting

1. Barotrauma:
   • Mechanism: Excessive airway pressure damages alveoli.
   • Prevention: Keep Pplat < 30 cmH₂O.
2. Volutrauma:
   • Mechanism: Overdistension from excessive tidal volumes.
   • Prevention: Use low tidal volume ventilation (6 mL/kg ideal body weight).
   • ARDSNet trial: 6 mL/kg → lower mortality compared to 12 mL/kg.
   • Ideal Body Weight: Based on height and sex, not actual weight.
   • Typical patient: Tidal Volume: 6–8 mL/kg IBW
   • ARDS: Tidal Volume: 4–6 mL/kg IBW
3. Atelectrauma:
   • Mechanism: Repeated opening/collapse of unstable alveoli.
   • Prevention: Optimize PEEP to keep alveoli open and reduce driving pressure.
4. Biotrauma:
   • Mechanism: Inflammatory cascade (↑ IL-6, TNF-α) from mechanical injury.
   • Effect: Can trigger systemic inflammation & multiorgan dysfunction.
   • Prevention: Minimize all other forms of VILI.

Post Peer Reviewed By: Marco Propersi, DO (Twitter/X: @Marco_propersi), and Mark Ramzy, DO (X: @MRamzyDO)

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