Peak Expiratory Flow in Children

Clinical Context and Guidelines

• The British Thoracic Society guidelines provide reference values showing that PEF varies significantly with height in children 1

Measurement and Interpretation

• Proper technique is essential in young children, as they often struggle to blow both "hard" and "long" simultaneously, and multiple attempts (minimum 3) should be recorded, with the highest value reported 2, 3, 4
• Visual inspection of the maneuver is critical to ensure rapid rise to peak flow without cough or glottic closure 3, 4
• Approximately 50% of children aged 4-8 years cannot perform PEF maneuvers adequately 5

Clinical Thresholds for Asthma Assessment

• The British Thoracic Society defines severity of asthma as: acute severe asthma: PEF <50% of predicted, and life-threatening asthma: PEF <33% of predicted 1, 6