Heart Rate Threshold for Severe Asthma/COPD Exacerbation
The heart rate threshold for severe asthma exacerbation is >110 beats per minute, as established by the British Thoracic Society guidelines. 1
Asthma-Specific Threshold
The British Thoracic Society explicitly defines heart rate >110 beats/min as one of the key features of severe asthma requiring immediate treatment. 1 This threshold appears alongside:
- Respiratory rate >25 breaths/min 1
- Peak expiratory flow <50% of predicted or best 1
- Inability to complete sentences in one breath 1
Life-Threatening Distinction
Importantly, bradycardia (not tachycardia) signals life-threatening deterioration in asthma exacerbations, indicating imminent cardiorespiratory arrest. 1 This represents a critical transition point where the patient has exhausted compensatory mechanisms.
COPD Exacerbation Considerations
No specific heart rate threshold exists in COPD exacerbation guidelines. 1 The COPD literature focuses on defining exacerbations by:
- Need for systemic corticosteroids or antibiotics 1
- Emergency department visits or hospitalizations 1
- Changes in respiratory symptoms and bronchodilator use 1
The absence of a heart rate threshold in COPD guidelines reflects the different pathophysiology and clinical presentation compared to acute asthma.
Critical Clinical Pitfalls
Beta-blocker use can mask tachycardia, eliminating this warning sign of severe exacerbation. 2 In patients taking beta-blockers, you cannot rely on heart rate to assess severity—other objective measures like peak flow and arterial blood gases become even more critical. 2
Never assume adequate compensation based on heart rate alone. The progression from tachycardia (>110 bpm) to bradycardia represents decompensation and impending respiratory failure requiring immediate intensive care intervention. 1