I. The clinical picture of asthma

Life-threatening asthma may be judged to be present in patients who, in the presence of a low FEV₁ are too dyspneic to speak, have altered consciousness or unequivocal cyanosis. Other physical signs which indicate airway obstruction of grave severity are pulsus paradoxus, gross thoracic overinflation and electrocardiographic evidence of pulmonary hypertension. A rise in the arterial CO₂ tension, the presence of pneumothorax or pneumomediastinum, and an FEV₁ less than 1 litre and vital capacity less than 0.5 litre, failing to increase immediately after inhalation of a bronchodilator, are also features which demand urgent and intensive therapy.Corticosteroids in large doses should be administered whenever a life-threatening situation is recognized. Systemic steroids should be stopped only when the danger phase, as indicated by the criteria given above, has been reversed. At all stages of therapy regular inhalations of a sympathomimetic bronchodilator should be maintained. Oral steroid therapy should be continued until maximum ventilatory function has been attained; only then should dose reduction be attempted.