From the Guidelines
The best ventilator settings for asthma patients focus on preventing dynamic hyperinflation and barotrauma while maintaining adequate gas exchange, using a low tidal volume strategy of 6-8 mL/kg ideal body weight with a respiratory rate of 8-12 breaths per minute, as recommended by the most recent guidelines 1.
Key Ventilator Settings
- Use a low tidal volume strategy of 6-8 mL/kg ideal body weight
- Respiratory rate of 8-12 breaths per minute
- Set a longer expiratory time by using an I:E ratio of 1:4 or 1:5 to allow for complete exhalation, as suggested by 1
- Keep plateau pressures below 30 cmH2O and peak pressures below 50 cmH2O to prevent barotrauma
- Start with low to moderate PEEP (3-5 cmH2O) as higher levels may worsen air trapping
- FiO2 should be titrated to maintain SpO2 > 92%
Permissive Hypercapnia
Permissive hypercapnia is often necessary, allowing pH to drop to 7.2-7.25 before increasing ventilation parameters, as this approach has been shown to reduce the risk of barotrauma 1.
Concurrent Medical Management
Concurrent medical management with bronchodilators (albuterol, ipratropium), corticosteroids (methylprednisolone 60-125 mg IV q6h), and possibly magnesium sulfate (2 g IV) or ketamine for refractory cases is essential, as recommended by 1.
Monitoring for Auto-PEEP
Monitor for auto-PEEP by performing end-expiratory hold maneuvers, and adjust settings if auto-PEEP exceeds 10-15 cmH2O, as suggested by 1. This approach balances the need for adequate ventilation while minimizing the risks of worsening air trapping and ventilator-induced lung injury, ultimately prioritizing morbidity, mortality, and quality of life as the outcome.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Ventilator Settings for Asthma
The goal of mechanical ventilation for patients with acute severe asthma is to ensure adequate oxygenation, ventilation, and gas exchange while preventing hyperinflation, auto-positive end-expiratory pressure, and subsequent barotrauma 2. Key considerations for ventilator settings include:
- Limitation of tidal volume size and respiratory rate
- Selection of specific inspiratory and expiratory ratios
- Use of positive end-expiratory pressure
- Application of helium-oxygen mixtures 2
Mechanical Ventilation Strategies
For patients with acute severe asthma, a strategy that prioritizes avoidance of ventilator-related complications over correction of hypercapnia is preferred 3. This approach involves:
- Standard therapy with inhaled bronchodilators, corticosteroids, and drugs used to facilitate controlled hypoventilation
- Nonconventional interventions such as heliox, general anesthesia, bronchoscopy, and extracorporeal life support may be considered in severe cases 3
- Interpretation of ventilator graphics and recommended mode of ventilation are crucial in managing patients with severe acute asthma requiring mechanical ventilation 4
Heliox-Driven Albuterol Nebulization
Heliox-driven albuterol nebulization has been shown to be effective in treating asthma exacerbations 5. Technical considerations for heliox-driven albuterol nebulization include:
- Optimal gas mixtures
- Flow-rate adjustment factors
- Nebulizer setup 5
Clinical Guidelines for Mechanical Ventilation
Evidence-based recommendations for choosing modes and setting parameters of mechanical ventilation are essential in treating acute respiratory insufficiency 6. The guideline covers the whole pathway of invasively ventilated patients, including:
- Indications of mechanical ventilation
- Ventilator settings
- Additional and rescue therapies
- Liberation from mechanical ventilation 6