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All patients with asthma are at risk of having exacerbations. Hospitalizations and emergency department (ED) visits account for a large proportion of the health-care cost burden of asthma, and avoidance or proper management of acute asthma (AA) episodes represent an area with the potential for large reductions in health-care costs. The severity of exacerbations may range from mild to life threatening, and mortality is most often associated with failure to appreciate the severity of the exacerbation, resulting in inadequate emergency treatment and delay in referring to hospital. This review describes the epidemiology, costs, pathophysiology, mortality, and management of adult AA in the ED and in the ICU. (CHEST 2004; 125:1081-1102)
Key words: acute asthma; anticholinergics; assessment; [beta]-agonists; corticosteroids; heliox; inhalation therapy; magnesium sulfate; mechanical ventilation; oxygen
Abbreviations: AA = acute asthma; ABG = arterial blood gases; APACHE II = acute physiology and chronic health evaluation; CPAP = continuous positive airway pressure; ED = emergency department; IB = ipratropium bromide; NIPPV = noninvasive positive pressure ventilation; PEEP = positive end-expiratory pressure; PEEPi = anto-positive endexpiratory pressure; PEFR = peak expiratory flow rate; pMDI = pressurized meter close inhaler; PP = pulsus paradoxus; RR = respiratory rate; SpO^sub 2^ = oxygen saturation by pulse oximetry; V/Q = ventilation/perfusion; VT = tidal volume
Asthma is a chronic inflammatory disorder of the airways associated with hyperresponsiveness, reversible airflow limitation, and respiratory symptoms.1,2 It is the most common chronic lung disease in both the developed and developing worlds. There is evidence that over the last 20 years its prevalence has increased worldwide.3-5 All patients with asthma are at risk of having exacerbations characterized by a progressive increase in shortness of breath, cough, wheezing or chest tightness, and by a decrease in expiratory airflow that can be quantified by simple measures of pulmonary function such as the peak expiratory flow rate (PEFR) and FEV^sub 1^. Terms like acute asthma (AA), asthma attack, or status astlimaticus have been used to describe this condition. The severity of exacerbations may range front mild to life threatening. Deterioration usually progresses over hours, days, or weeks; however, a few patients have sudden (over minutes) and unexpected increases in airway obstruction. Epidemic asthma, the simultaneous occurrence in place and time of an unusually high number of...