What are the indications and contraindications for spirometry?

Indications and Contraindications for Spirometry

Spirometry is indicated for diagnosis and monitoring of respiratory diseases in symptomatic patients but should not be used as a screening tool in asymptomatic individuals due to lack of demonstrated benefit. 1

Indications for Spirometry

Diagnostic Purposes

• Evaluation of patients with respiratory symptoms such as:
  • Chronic cough (particularly worse at night)
  • Recurrent wheezing
  • Recurrent difficulty breathing
  • Recurrent chest tightness 2
• Diagnosis of obstructive lung diseases:
  • Asthma (to demonstrate airflow obstruction and assess reversibility)
  • COPD (post-bronchodilator FEV1/FVC <0.70) 2
• Evaluation of chronic cough lasting more than 2 weeks 2
• Assessment of patients with suspected restrictive lung disorders

Monitoring and Management

• Monitoring disease progression in known respiratory conditions
• Evaluating response to treatment in asthma and COPD
• Preoperative assessment of pulmonary function 1

Specific Clinical Scenarios

• Assessment of airflow obstruction in patients with risk factors for COPD (smoking history, occupational exposures) 2
• Bronchoprovocation testing when asthma is suspected but baseline spirometry is normal 2
• Evaluation of patients with suspected vocal cord dysfunction (using inspiratory flow-volume loops) 2

Contraindications for Spirometry

Absolute Contraindications

• Active hemoptysis
• Pneumothorax
• Recent myocardial infarction or unstable angina
• Recent thoracic, abdominal, or eye surgery
• Thoracic or abdominal aortic aneurysm
• Acute respiratory distress 1

Relative Contraindications

• Severe nausea or vomiting
• Recent cerebral event
• Hemodynamic instability
• Inability to properly perform the maneuver (cognitive impairment, severe pain)
• Transmissible respiratory infections 1

Clinical Implementation

Technical Considerations

• Spirometry should be performed after administration of an adequate dose of at least one short-acting inhaled bronchodilator to minimize variability when assessing for COPD 2
• For asthma diagnosis, reversibility is determined by an increase in FEV1 of >200 mL and 12% from baseline after bronchodilator administration 2
• Spirometry is generally recommended over peak flow measurements due to wide variability in peak flow meters and reference values 2

Interpretation Considerations

• A post-bronchodilator fixed ratio of FEV1/FVC less than 0.70 is the spirometric criterion for airflow limitation in COPD 2
• Primary measurements include FVC, FEV1, and their ratio (FEV1/FVC) 3
• Technical adequacy of spirometry is crucial - studies show that approximately 71% of tests performed in primary care settings are technically adequate for interpretation 4

Important Caveats

• Spirometry alone is not sufficient for diagnosis - clinical symptoms and history remain essential components of respiratory disease diagnosis 1
• The U.S. Preventive Services Task Force recommends against screening asymptomatic individuals for COPD using spirometry, as there is at least moderate certainty that it provides no net benefit 2
• Spirometry can lead to substantial overdiagnosis of COPD in "never smokers" older than 70 years 2
• Family physicians can perform and interpret spirometry with acceptable accuracy (76% concordance with pulmonary expert interpretations) 4

Proper patient positioning, clear instructions, and demonstrations are essential when performing spirometry, with adequate rest between maneuvers and observation for signs of distress during testing to ensure accurate and reliable results 1.