How can peak pressure be reduced on a ventilator?

Strategies to Reduce Peak Pressure on Mechanical Ventilation

The most effective way to reduce peak pressure (Ppeak) on a ventilator is to decrease tidal volume to 6-8 mL/kg of predicted body weight while adjusting respiratory rate and inspiratory:expiratory ratio to allow for adequate ventilation and expiration. 1

Primary Strategies

Tidal Volume Adjustment

• Reduce tidal volume to 6-8 mL/kg of predicted body weight to minimize volutrauma and decrease peak airway pressure 1
• Further reduction to as low as 4 mL/kg may be necessary if plateau pressure remains >30 cmH2O despite initial reduction 1
• Reducing tidal volume has been shown to eliminate ineffective triggering in two-thirds of patients with ventilator asynchrony 2

Inspiratory Flow Rate and I:E Ratio Adjustment

• Use shorter inspiratory time with higher inspiratory flow rates (80-100 L/min) to allow for longer expiratory time 1
• Adjust I:E ratio to 1:4 or 1:5 for patients with obstructive disease to prevent air trapping 1
• This modification is particularly important for patients with asthma or COPD to prevent auto-PEEP 1

Respiratory Rate Modification

• Use a slower respiratory rate (10-15 breaths/min) with smaller tidal volumes to reduce peak pressures 1
• This approach allows for more complete exhalation and reduces the risk of breath stacking 1

Secondary Strategies

PEEP Optimization

• Start with PEEP of 5 cmH2O and individualize thereafter based on patient response 1, 3
• Optimal PEEP should be set to prevent alveolar collapse while avoiding increases in driving pressure 3
• For patients with auto-PEEP, temporarily disconnecting from the ventilator circuit can allow PEEP to dissipate 1

Ventilator Mode Selection

• Pressure-controlled ventilation may be preferred over volume-controlled ventilation for patients with high peak pressures 1, 4
• Pressure-controlled ventilation limits the maximum pressure delivered while allowing volume to vary 1

Patient-Ventilator Synchrony

• Ensure adequate sedation to reduce ventilator dyssynchrony and decrease work of breathing 1
• Consider short-term neuromuscular blockade for severe asynchrony in ARDS patients 5

Special Considerations

For Obstructive Disease (Asthma/COPD)

• Use permissive hypercapnia strategy to reduce barotrauma risk 1
• Monitor for auto-PEEP development, which can lead to hyperinflation, tension pneumothorax, and hypotension 1
• If auto-PEEP causes significant hypotension, assist with exhalation by pressing on the chest wall after disconnection of the ventilator circuit 1

For ARDS Patients

• Use lung-protective ventilation strategy with low tidal volumes (4-8 mL/kg PBW) 1, 5
• Accept higher PaCO2 levels (permissive hypercapnia) if necessary to maintain low peak pressures 1, 5
• Consider prone positioning for severe refractory hypoxemia 1

Monitoring and Troubleshooting

Key Parameters to Monitor

• Plateau pressure (goal <30 cmH2O) 1
• Driving pressure (Pplat-PEEP) 1, 3
• Dynamic compliance 1
• Patient comfort and ventilator synchrony 1

Common Pitfalls

• Remember the "DOPE" mnemonic for sudden deterioration in ventilated patients: tube Displacement, tube Obstruction, Pneumothorax, Equipment failure 1
• Avoid excessive PEEP which can increase intrathoracic pressure and worsen hemodynamics 1
• Be cautious with recruitment maneuvers - use the lowest effective pressure and shortest effective time 1

By implementing these strategies systematically, peak airway pressures can be effectively reduced while maintaining adequate ventilation and oxygenation, ultimately improving patient outcomes and reducing the risk of ventilator-induced lung injury.