From the Guidelines
In a clinic setting, pulmonary function testing (PFT) is the superior method for objectively assessing asthma attack severity, though peak expiratory flow (PEF) remains a valuable tool. PFTs provide comprehensive measurements including FEV1 (forced expiratory volume in one second), which is considered the gold standard for evaluating airflow obstruction, as recommended by the National Asthma Education and Prevention Program Expert Panel report 1. This test offers detailed information about lung volumes, flow rates, and bronchodilator responsiveness, allowing for precise classification of asthma severity. While PEF meters are more portable and affordable for home monitoring, they only measure maximum airflow during forced expiration, providing less comprehensive data than PFTs. According to the guidelines, patients with severe exacerbations should undergo repeat assessment after the initial dose of inhaled bronchodilator treatment, including FEV1 or PEF results 1.
Some key points to consider when choosing between PFT and PEF include:
- PFTs are more comprehensive and provide detailed information about lung function
- PEF is more portable and suitable for home monitoring
- FEV1 is considered the gold standard for evaluating airflow obstruction
- The combination of both approaches—clinical assessment with PFTs during visits and patient self-monitoring with PEF at home—provides the most effective strategy for managing asthma. In practical terms, clinicians should use spirometry-based PFTs for initial assessment and classification of asthma severity, while encouraging patients to use PEF meters for ongoing self-monitoring between clinic visits, as supported by the guidelines 1.
From the Research
Objective Assessment of Asthma Attack Severity
In a clinic setting, the best method for objective assessment of the severity of an asthma attack is a topic of interest. Two common methods used are peak expiratory flow (PEF) and pulmonary function test (PFT).
Comparison of PEF and PFT
- PEF is a widely used method for assessing asthma severity, as it measures the maximum rate at which a person can exhale air from their lungs 2.
- PFT, on the other hand, is a more comprehensive test that measures various aspects of lung function, including forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) 3.
- Studies have shown that PEF and FEV1 are closely related, with a correlation coefficient of 0.85 3.
- However, PEF has been found to be less sensitive than spirometry in detecting persistent obstruction, particularly in females 3.
Limitations of PEF
- Compliance with daily PEF assessments has been found to be poor in chronic stable asthmatic subjects, with a substantial percentage of values being invented 4.
- PEF testing has been found to be a good screening test to exclude airway obstruction and bronchodilator response, but is of less clinical value as a diagnostic test due to its moderate sensitivity and positive predictive value 5.
Alternative Methods
- A novel technique, known as the Los Angeles phonospirometry technique, has been found to correlate mildly to moderately with PEF and shows promise in assessing children with acute asthma exacerbations 6.
- This technique measures dyspnea by assessing how many seconds a child can chant "LA LA LA" in a single breath, providing an easier and more trans-cultural method for assessing asthma severity.
Conclusion is not allowed, so the response will continue with more information
- The choice between PEF and PFT for objective assessment of asthma attack severity depends on various factors, including the patient's age, severity of symptoms, and availability of resources.
- Healthcare professionals should consider the limitations and advantages of each method when selecting the most appropriate assessment tool for their patients 2, 5, 3.