Figure 4).

Changes in daytime asthma score and morning peak expiratory flow (PEF) in relation to whether the exacerbation was diagnosed by the need for oral steroids or by a fall in PEF. The values for evening PEF and nocturnal symptoms (not shown) were similar. Note: Changes in peak flow rates and symptoms generally move together, such that reductions in PEF are associated with increased symptoms and vice versa. However, most action plans are symptom-based and do not take into account PEF changes. OCS Oral corticosteroids. Adapted from reference 12