A ship sinks at sea. The occupants are left floating in the ocean aided only by their life preservers and buoyant pieces of debris. Fortunately, a Coast-Guard cutter, attracted by an SOS sent from the sinking ship, arrives and saves the day. This is a rescue.
Asthma is characterised by episodes of acutely worsening airflow, secondary to bronchospasm. An asthmatic, when exposed to a trigger, may develop acute bronchospasm, together with frightening and sometimes life-threatening symptoms. Rapid-acting bronchodilators, administered in a timely way, can reverse the bronchospasm, thus saving the day. This is termed “rescue” in asthma therapy.
Acute episodes of asthma can be initiated by a variety of triggers ranging from cold air, cigarette smoke, dust, perfume and viral infections, to a variety of allergens including animal dander, insect and mite proteins, plant pollens and mould spores. An asthma attack can vary in severity, rate of onset and rate of resolution. Unexpected symptoms may be less dramatic and relatively mild and may commonly occur in some asthmatics. Unscheduled use of rapid-acting bronchodilators taken for acute symptom relief for all these various episodes is termed “rescue”.
This use of rescue treatment has several utilities. Reserving the term rescue for severe “attacks” would require a definition of attacks, a daunting prospect. The concept also has mechanistic validity. The airway in the asthmatic with baseline conditions has its “normal” luminal diameter and airway tone. In response to a stimulus, airway tone acutely increases while airflow acutely decreases. Therefore, when the …