Characteristics of patients with soybean dust-induced acute severe asthma requiring mechanical ventilation

Patients presenting with acute severe asthma during the Barcelona's outbreaks caused by soybean dust inhalation from August, 1981, through September, 1987, characteristically showed an abrupt severe onset of each attack followed by a rapid relief of symptoms after treatment. To throw further light on clinical findings, pathophysiology and outcome in the most life-threatening episodes, we reviewed records of acute severe asthma patients treated by mechanical ventilation in one of the four main hospitals of the city. Twelve such patients (15 episodes) were compared to 24 non-epidemic asthmatic patients (25 episodes) also treated by mechanical ventilation in the same institution during the same period of time. There was a male predominance during outbreaks (p less than 0.03) and epidemic patients were ventilated fewer hours (12 +/- 8 h) (mean +/- SD), admitted fewer days to intensive care (1.6 +/- 0.7 days), and hospitalized fewer days (7.1 +/- 4.4 days) than non-epidemic patients (65 +/- 84 h, 4.6 +/- 3.8 days (p less than 0.001, each), and 16.0 +/- 13.2 days (p less than 0.004), respectively). These differences together with both the fulminant presentation of the episodes of epidemic asthma and the point-source origin of the asthma outbreaks previously shown are consistent with the unusual nature of the aetiologic agent, soybean dust.