Part 10.5: Near-Fatal Asthma

Asthma accounts for >2 million emergency department visits and 5000 to 6000 deaths annually in the United States, many occurring in the prehospital setting.1 Severe asthma accounts for approximately 2% to 20% of admissions to intensive care units, with up to one third of these patients requiring intubation and mechanical ventilation.2 This section focuses on the evaluation and treatment of patients with near-fatal asthma.The pathophysiology of asthma consists of 3 key abnormalities:Complications of severe asthma, such as tension pneumothorax, lobar atelectasis, pneumonia, and pulmonary edema, can contribute to fatalities. Cardiac causes of death are less common.Wheezing is a common physical finding, but severity does not correlate with the degree of airway obstruction. The absence of wheezing may indicate critical airway obstruction, whereas increased wheezing may indicate a positive response to bronchodilator therapy.Oxygen saturation (Sao2) levels may not reflect progressive alveolar hypoventilation, particularly if O2 is being administered. Note that the Sao2 may initially fall during therapy because β-agonists produce both bronchodilation and vasodilation and may initially increase intrapulmonary shunting.Other causes of wheezing are pulmonary edema, chronic obstructive pulmonary disease (COPD), pneumonia, anaphylaxis,3 foreign bodies, pulmonary embolism, bronchiectasis, and subglottic mass.4Patients with severe life-threatening asthma require urgent and aggressive treatment with simultaneous administration of oxygen, bronchodilators, and steroids. Healthcare providers must monitor these patients closely for deterioration. Although the pathophysiology of life-threatening asthma consists of bronchoconstriction, inflammation, and mucous impaction, only bronchoconstriction and inflammation are amenable to drug treatment. If the patient does not respond to therapy, consultation or transfer to a pulmonologist or intensivist is appropriate. Primary Therapy Oxygen Provide oxygen to all patients with severe asthma, even those with normal oxygenation. Titrate to maintain Sao2 >92%. As noted above, successful …