Lung Protective Ventilation Strategy

Written on 10/10/2024
jombuatapp

Implementing a lung protective ventilation strategy is crucial for patients with Acute Respiratory Distress Syndrome (ARDS) and can also be beneficial for patients with normal lungs to prevent ventilator-induced lung injury (VILI).

 

1. Low Tidal Volume (TV)

  • Initial TV: 4–8 mL/kg of Ideal Body Weight (IBW).

    • Start at 6 mL/kg and adjust based on plateau pressures.

  • Rationale: Lower tidal volumes reduce alveolar overdistension, decreasing the risk of barotrauma and volutrauma.

 

2. Respiratory Rate (RR)

  • Initial RR: Adjust to achieve a target minute ventilation of 70–100 mL/kg/min.

    • Minute Ventilation (VE) = RR × TV.

  • Rationale: Compensate for the lower tidal volumes by increasing RR to maintain adequate CO₂ elimination.

 

3. Positive End-Expiratory Pressure (PEEP)

  • Initial PEEP: 5 cm H₂O.

  • Adjust PEEP: According to FiO₂ requirements and oxygenation targets.

    • Following ARDSnet PEEP/FiO₂ tables.

  • Rationale: PEEP prevents alveolar collapse at end-expiration, improving oxygenation and reducing atelectrauma.

 

4. Fraction of Inspired Oxygen (FiO₂)

  • Initial FiO₂: 1.0 (100%).

    • Titrate FiO₂: Gradually decrease to maintain target oxygenation while minimizing oxygen toxicity.

  • Rationale: Begin with high FiO₂ for rapid oxygenation; reduce to avoid oxygen toxicity.

 

5. Monitor and Adjust Plateau Pressure (Pplat)

  • Target Pplat: Maintain between 25–30 cm H₂O.

  • Measurement: Perform an inspiratory hold (pause) to measure Pplat.

 

Adjustments Based on Pplat:

If Pplat >30 cm H₂O:

  • Decrease TV by 1 mL/kg increments (minimum TV of 4 mL/kg).

If Pplat <25 cm H₂O 

  • Increase TV by 1 mL/kg increments (maximum TV of 6 mL/kg).

 

 

6. Goals of Lung Protective Strategy

i. Oxygenation Targets:

  • PaO₂: 55–80 mm Hg.

  • SpO₂: 88–95%.

    ii. Ventilation Targets:

  • pH: 7.15–7.30.

  • Action: Adjust RR to manage pH and PaCO₂ levels.

  • Permissive Hypercapnia: Allow elevated PaCO₂ as long as pH remains ≥7.15.

 

Additional Considerations

i. Permissive Hypercapnia

  • Accept Higher PaCO₂: To maintain low tidal volumes and pressures.
  • Monitor pH: Maintain arterial pH ≥7.15.
  • Interventions:
    • Adjust RR cautiously to prevent auto-PEEP.
    • Use buffering agents (e.g., sodium bicarbonate) if pH falls below 7.15.

 

ii. FiO₂ and PEEP Adjustment

  • Use ARDSnet PEEP/FiO₂ Tables: To balance oxygenation and minimize FiO₂ toxicity.
  • Incremental Changes: Adjust PEEP and FiO₂ together to achieve oxygenation goals safely.

 

Lower PEEP/Higher FiO₂ Strategy

FiO₂ PEEP (cm H₂O)
0.30 5
0.40 5
0.50 8
0.60 10
0.70 10
0.80 12
0.90 14
1.00 14-18

 

Higher PEEP/Lower FiO₂ Strategy

FiO₂ PEEP (cm H₂O)
0.30 5
0.30 8
0.40 10
0.50 14
0.60 16
0.70 18
0.80 20
0.90 22
1.00 22-24

 

How to Use the Table:

A. Initial Settings:

  • Start with FiO₂ of 1.0 (100%) and PEEP of 5 cm H₂O.
  • Aim for SpO₂ between 88-95% or PaO₂ between 55-80 mm Hg.

 

B. Adjust FiO₂ and PEEP Together:

  • If oxygenation is adequate, reduce FiO₂ to minimize oxygen toxicity.
  • As you decrease FiO₂, increase PEEP according to the table to maintain oxygenation.

 

C. Selection of Strategy:

i. Lower PEEP/Higher FiO₂:

  • Use when concerned about hemodynamic instability due to higher PEEP levels.

ii. Higher PEEP/Lower FiO₂:

  • Beneficial in moderate to severe ARDS to improve alveolar recruitment.