Should pulmonary function tests (PFTs) be performed during an acute exacerbation of chronic obstructive pulmonary disease (COPD) or other respiratory conditions?

From the Guidelines

Pulmonary function tests (PFTs) should not be routinely performed during a cold exacerbation, as they may not accurately reflect the patient's baseline lung function and can be uncomfortable for the patient. According to the guidelines for managing asthma exacerbations, serial measurement of lung function by using either FEV1 or PEF is useful in categorizing the severity of the exacerbation, but it is not recommended in patients with severe or life-threatening exacerbations with obvious airway compromise and cyanosis 1. In such cases, physical presentation and pulse oximetry are sufficient for initial clinical assessment.

The evidence suggests that assessment of lung function is more difficult in children, and pulse oximetry is recommended for assessment of lung function in infants and young children 1. Additionally, studies have shown that acute spirometry is not useful in the management of acute exacerbations of chronic obstructive pulmonary disease (COPD) 1.

Key points to consider when deciding whether to perform PFTs during a cold exacerbation include:

• The potential for inaccurate results due to temporary changes in lung function
• The discomfort and potential exacerbation of symptoms for the patient
• The risk of spreading infection to other vulnerable patients in a pulmonary function laboratory
• The availability of alternative methods for assessing lung function, such as pulse oximetry and physical examination.

In general, it is recommended to postpone PFTs until at least 4-6 weeks after recovery from a respiratory infection, when the patient's lung function is more likely to reflect their baseline status. If PFTs are absolutely necessary during an exacerbation, the results should be interpreted with caution and clearly documented as having been obtained during an acute illness.

From the Research

Pulmonary Function Tests During Cold Exacerbation

• Pulmonary function tests (PFTs) are valuable investigations in the management of patients with suspected or previously diagnosed respiratory disease, including during cold exacerbations 2.
• These tests can aid in diagnosis, monitor response to treatment, and guide decisions regarding further treatment and intervention 2.
• In the context of acute bronchitis, PFTs have shown reversible airway obstruction, suggesting a role for bronchospasm in many cases 3.
• The use of PFTs, such as spirometry and lung volumes, can help quantify symptoms like dyspnea and indicate both respiratory and non-respiratory disorders 4.
• However, the diagnosis and treatment of acute bronchitis should be differentiated from other common diagnoses, such as pneumonia and asthma, as these conditions may require specific therapies not indicated for bronchitis 5.

Considerations for PFTs During Cold Exacerbation

• PFTs can be useful in monitoring the progression of respiratory disease and guiding treatment decisions during cold exacerbations 2, 3.
• The interpretation of PFTs requires knowledge of respiratory physiology, and results should be considered in the context of the patient's overall clinical presentation 2, 4.
• While PFTs can provide valuable information, they should be used in conjunction with other diagnostic tools and clinical judgment to guide treatment decisions 2, 5.