Target Oxygen Saturation During an Asthma Attack
General Principles of Oxygen Therapy in Asthma
- The American Academy of Allergy, Asthma, and Immunology recommends oxygen administration as a primary treatment for all asthma exacerbations, alongside inhaled β2-agonists and systemic corticosteroids 1
- Oxygen should be delivered through nasal cannulae or mask to maintain the target saturation levels 1
- Oxygen saturation should be continuously monitored until a clear response to bronchodilator therapy has occurred 1
Specific Target Ranges
- The standard target range for asthma patients is 94-98% 2, 3
- Pregnant women and patients with concomitant heart disease require higher targets, greater than 95% 1
Oxygen Delivery Methods
- For mild to moderate exacerbations, nasal cannulae at 2-6 L/min or simple face mask at 5-10 L/min can be used 4, 5
- For severe exacerbations with saturation below 85%, a reservoir mask at 15 L/min can be used 5
Monitoring Considerations
- Pulse oximetry should be used to guide oxygen therapy throughout treatment 1
- Tachypnea and tachycardia are more common indicators of hypoxemia than visible cyanosis 6
Nebulizer Therapy and Oxygen
- Nebulizers should be driven by oxygen at a flow rate of greater than 6 L/min 4
- After nebulizer treatment is complete, return the patient to their usual oxygen delivery device 4
Common Pitfalls to Avoid
- Do not discontinue oxygen therapy to obtain room air measurements in patients who clearly require oxygen 6
- Do not delay transport to hospital when administering bronchodilator treatments in pre-hospital settings 1
- Be aware that bronchodilator therapy itself may sometimes cause pulmonary vasodilation leading to V/Q mismatch and reduced blood oxygen levels 4