Emergency Management of Severe Asthma with Hypoxemia

Immediate Assessment and Treatment

• The British Thoracic Society recommends immediately administering high-flow oxygen, nebulized salbutamol, and systemic corticosteroids within the first few minutes of arrival for patients with severe asthma and hypoxemia 1, 2, 3.
• The American Thoracic Society suggests targeting SpO2 94-98% for patients without COPD risk factors, and using reservoir mask at 15 L/min if initial SpO2 <85% 1.

First-Line Treatment

• The British Thoracic Society recommends administering salbutamol 5 mg or terbutaline 10 mg via oxygen-driven nebulizer immediately, and repeating every 20 minutes for 3 doses 2, 3, 7.
• The American College of Chest Physicians suggests giving prednisolone 30-60 mg orally or hydrocortisone 200 mg IV immediately, as corticosteroids take 6-12 hours to show effect 2, 3, 8.

Monitoring and Reassessment

• The British Thoracic Society recommends measuring PEF or FEV1 before and after each treatment, and monitoring oxygen saturation continuously 2, 4.
• The American Thoracic Society suggests repeating arterial blood gases within 2 hours if initial PaO2 <8 kPa or if PaCO2 was normal/elevated 2, 5, 6.

Criteria for ICU Transfer

• The Society of Critical Care Medicine recommends transferring patients to the ICU immediately if they have deteriorating PEF despite treatment, worsening or persisting hypoxia, hypercapnia, exhaustion, confusion, drowsiness, or altered mental status 2, 5, 6, 7.

Hospital Admission Criteria

• The American Academy of Allergy, Asthma, and Immunology suggests admitting patients if they have any life-threatening features present, features of severe attack persist after initial treatment, PEF remains <33% predicted after treatment, or PEF <50% predicted after 1-2 hours of intensive treatment 2, 3, 4, 5.