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Inhalation Challenge Test
Aka: Inhalation Challenge Test, Inhalation Bronchial Challenge Test, Methacholine Challenge, Pulmonary Methacholine Challenge Test, Pulmonary Function Challenge Test, Bronchoprovocation
- See Also
- Pulmonary Function Test
- Lung Volumes
- Diffusing Capacity
- Exercise Spirometry
- Functional Residual Capacity
- Vital Capacity
- Peak Expiratory Flow Rate (PEFR)
- Spirometry Lower Limit of Normal (PFT LLN)
- Obstructive Lung Disease
- Restrictive Lung Disease
- Indication
- Suspected allergen or Exercise-Induced Asthma (despite normal lung function tests)
- Contraindications
- FEV1 <65% of predicted
- Physiology
- Tests airway reactivity to airway constrictors
- Technique
- Equipment to treat Status Asthmaticus readily available
- Pulmonary Function Tests performed at baseline
- Exposure to airway constrictor or irritant
- Methacholine (most common)
- Mannitol (lower Test Sensitivity than methacholine but higher Specificity)
- Histamine
- Cold Air
- Hypertonic mist or hypotonic mist
- Pulmonary Function Tests repeated after exposure
- Interpretation
- Negative test
- Suggests Asthma not present
- Positive test criteria
- Methacholine
- Exposure to Inhaled Methacholine at 4 mg/ml or less
- FEV1 declines 20%
- Mannitol
- Exposure to cummulative dose of 635 mg or less of Mannitol
- FEV1 decline of 15% or FEV1 declines 10% between 2 consecutive doses
- Positive test
- False positive in 8% of normal patients
- Asthma
- Emphysema
- Bronchiectasis
- Cystic Fibrosis
- References
- Crapo (2000) Am J Respir Crit Care Med 161:309-29 [PubMed]
- Randolph (2011) Curr Allergy Asthma 11(6): 482-90 [PubMed]