Management of acute asthma in adults in the emergency department: nonventilatory management.

Acute asthma is a common medical emergency, which, despite repeated review and the publication of international and national guidelines, including the Canadian Asthma Consensus Guidelines, often remains poorly managed. Although there are some signs that evidence-based management of this disorder is improving, a recent survey of the management of asthma in children and adults in the emergency department revealed wide variations in care and substantial gaps in management in certain key areas. These included poor adherence to published guidelines on the management of asthma, infrequent measurement of peak expiratory flow, infrequent use of systemic cortico steroids and poor rates of referral to asthma educational services. Exacerbations of asthma account for about 25% of the total costs of asthma care in Canada. Most exacerbations treated in the emergency department resolve within two hours after presentation. Only about 6%–13% of affected patients require admission to hospital, and far fewer require admission to a critical care unit. The most common triggers of exacerbations are viral infections and environmental allergens. Exposures in the workplace (to allergens, sensitizers or irritants) can also trigger exacerbations. The onset and duration of symptoms and the worsening of airflow obstruction before presentation are variable, but these problems usually occur over several hours. Even in fatal or near-fatal attacks, this means there is potential for early recognition and aggressive treatment. Rarely, a patient has rapid, catastrophic onset of acute asthma, which can be fatal. Whether this reflects a separate phenotype of asthma is unclear. Although the prevalence of asthma is increasing, the overall rate of death from asthma has been falling in Canada, from 400–500 deaths in 1995 to 268 deaths in 2004. Asthma mortality rates increase with age. Overall mortality from acute exacerbations is low (< 0.1%), and most deaths related to asthma occur before arrival at a hospital. There are many risk factors for death or near death from acute asthma (Table 1), but a key contributor is failure of patients or physicians to appreciate the severity of the exacerbation, which leads to delayed and insufficiently aggressive treatment. 77 Of note, both heightened and blunted perception of asthma symptoms have been implicated in excess morbidity and mortality related to asthma. Patients with blunted perception of their symptoms do not recognize that an exacerbation is occurring and therefore permit the exacerbation to progress before seeking help. Patients with heightened sensi-