Definition of critical asthma syndromes.

Urgent visits to the clinic and emergency department for acute severe asthma exacerbations are all too frequent. Existing national guidelines do not present consistent or specific recommendations for the evaluation and treatment of individual asthma patients in respiratory distress. In this vein, we propose the term "critical asthma syndrome" (CAS) to describe any child or adult who is at high risk for fatal asthma. Acute severe asthma, refractory asthma, status asthmaticus, and near-fatal asthma all describe CAS where physical exhaustion from the overwhelming work of breathing leads to respiratory arrest and death from hypoxia or related complications. The authors of this supplement seek to emphasize the importance of early recognition, prompt and coordinated evaluation, and treatment of CAS in the emergency department, hospital, and intensive care units by experienced healthcare provider teams. CAS is not severe persistent asthma where control of symptoms and prevention of exacerbations are targets of chronic disease management in the outpatient setting. The authors address the distinctions between the two entities throughout the supplement, and elaborate on the considerations important in the care of a critically ill patient, including the common errors to avoid. In addition, gaps in knowledge and clinical experience in regards to critical asthma are highlighted. Knowledge gaps include a lack of understanding of how to recognize CAS, how to coordinate and integrate hospital and outpatient resources, when to further phenotype patients with critical asthma in order to facilitate effective treatment, and how to prevent future acute exacerbations. Lastly, CAS is complicated by the fact that asthma care in diverse healthcare settings is haphazard. We recommend that primary care physicians refer patients promptly to an asthma specialist for consultation to reduce the frequency of acute exacerbations and prevent the development of CAS.