Treatment of Very Severe Status Asthmaticus
The treatment of very severe status asthmaticus requires immediate high-flow oxygen, aggressive bronchodilator therapy with nebulized beta-agonists (salbutamol/albuterol 5-10 mg) every 15-30 minutes, systemic corticosteroids, and consideration of adjunctive therapies including ipratropium bromide and IV magnesium sulfate. 1
Initial Management
First-Line Interventions
- High-flow oxygen: Administer 40-60% oxygen via face mask to maintain SpO₂ >92% 1
- Nebulized beta-agonists:
- Systemic corticosteroids:
- Ipratropium bromide: Add 0.5 mg to nebulizer and repeat every 6 hours until improvement 1
Monitoring
- Continuous pulse oximetry (maintain SpO₂ >92%)
- Repeat peak expiratory flow (PEF) measurements 15-30 minutes after starting treatment
- Monitor vital signs (heart rate, respiratory rate)
- Assess for life-threatening features:
- PEF <33% of predicted/best
- Silent chest, cyanosis, poor respiratory effort
- Fatigue, exhaustion, altered consciousness 1
Escalation of Care (If No Improvement After Initial Treatment)
Second-Line Interventions
- Continue oxygen and corticosteroids
- Increase frequency of nebulized beta-agonists to every 15-30 minutes 1
- IV magnesium sulfate: 2g administered over 20 minutes (for severe refractory asthma) 1
- IV aminophylline:
- Loading dose: 5 mg/kg over 20 minutes (omit if already on oral theophyllines)
- Maintenance: Small patient 750 mg/24 hours, large patient 1500 mg/24 hours 1
- Monitor blood concentrations if continued for over 24 hours
- Alternative: Salbutamol or terbutaline infusion instead of aminophylline 1
Intensive Care Considerations
Indications for ICU Transfer
- Deteriorating PEF despite maximal therapy
- Persistent or worsening hypoxia (PaO₂ <8 kPa/60 mmHg) despite oxygen
- Hypercapnia (rising PaCO₂)
- Exhaustion, feeble respirations, confusion, drowsiness
- Respiratory arrest or impending respiratory failure 1, 2
Intubation and Mechanical Ventilation
- Decision to intubate is based primarily on clinical judgment 2
- Absolute indications: cardiac or respiratory arrest 2
- Relative indications: exhaustion despite maximal therapy, deteriorating mental status, refractory hypoxemia, increasing hypercapnia, hemodynamic instability 2
Ventilation Strategy
- Focus on preventing further hyperinflation and ventilator-associated lung injury 2
- Allow permissive hypercapnia (accept higher PaCO₂ levels) to avoid excessive lung inflation 3
- Limit minute ventilation and prolong expiratory time 3
- Monitor lung mechanics carefully 2
Sedation for Intubation
- Benzodiazepines or propofol (preferred for potential rapid extubation) 2
- Consider adding opioids (fentanyl or remifentanil) for analgesia and respiratory drive suppression 2
- Avoid paralytic agents if possible due to risk of ICU myopathy 3
Important Caveats and Pitfalls
- Avoid sedatives of any kind during initial management 1
- Do not give bolus aminophylline to patients already taking oral theophyllines unless blood levels are known 1
- Subjective assessment of airway obstruction is often inaccurate; rely on objective measures 4
- Pulse oximetry >90% can be falsely reassuring; CO₂ retention may still be present 4, 5
- Clinical presentation does not always predict outcome; close monitoring is essential even if initial response seems favorable 2
- Delay in corticosteroid administration can worsen outcomes; administer early as benefits may not be apparent for 6-12 hours 4, 5
Follow-up After Acute Phase
- Continue prednisolone 30-60 mg daily or IV hydrocortisone 200 mg every 6 hours
- Continue nebulized beta-agonists every 4-6 hours
- Ensure patient has own PEF meter and written self-management plan
- Arrange follow-up with primary care within 1 week
- Schedule respiratory clinic appointment within 4 weeks 1
By following this aggressive, systematic approach to treating very severe status asthmaticus, you can optimize outcomes and reduce the risk of mortality in this life-threatening condition.