Management of life-threatening asthma in adults

Abstract

Asthma is a disease of predominantly reversible airway obstruction characterized by a triad of bronchial smooth muscle contraction, airway inflammation, and increased secretions; it is a major health problem for all age groups. For the majority, control of asthma symptoms is readily achieved; however, in a small minority, asthma may cause death. Although the mortality rate for asthma in those aged less than 65 yrs is now falling, there remain around 1400 asthma deaths in the UK each year (http:// www.laia.ac.uk/kf_asthma_03.htm). Most of these occur in the pre-hospital setting and, in retrospect, the majority is considered potentially preventable. Factors associated with asthma death include disease severity, inadequate treatment, inadequate monitoring, the under use of written asthma management plans and adverse psychosocial and behavioural factors (www.sign.ac.uk/guidelines/fulltext/63/ index.html). Levels of severity of acute asthma exacerbations have been defined. The features of acute severe, life–threatening, and near fatal asthma are listed in Table 1. Of note, patients with life-threatening asthma may not appear distressed and might only display one of the features listed. Life-threatening asthma tends to occur as two sub-types. Most commonly, there is a history of progressive worsening of symptoms over several days; the majority of patients in this group report nocturnal dyspnoea in the previous three nights. As a result of greater bronchial inflammation and mucous secretion, this group (occurring more frequently in females) tends to respond more slowly to treatment. In contrast, a smaller sub-group, more frequently male, presents with a rapidly progressive condition with highly reactive airways. These patients have intense bronchospasm that often responds more rapidly to bronchodilator therapy. In February 2003, The British Thoracic Society together with the Scottish Intercollegiate Guidelines Network published guidelines on the management of asthma (http://www.britthoracic.org.uk/asthma-guideline-download.html). They were updated in November 2007. In common with other recommendations, these give guidance only up to the commencement of intensive care. Evidence for therapies in intensive care from randomized controlled trials remains sparse. Ongoing management of lifethreatening episodes (Fig. 1) is often difficult with rapid and dynamic changes in physiology. Complications of treatment are frequent.