High-dose intravenous magnesium sulfate in the management of life-threatening status asthmaticus.

In severe status asthmaticus basic medical treatment often fails to improve the patient's condition. Mechanical ventilation in this situation is associated with a high incidence of serious complications. After the bronchodilating effect of moderate-dose magnesium sulfate in asthmatic patients had been demonstrated in previous studies we treated five mechanically ventilated patients with refractory status asthmaticus successfully with high dosages of MgSO4 IV (10-20 g within 1 h depending on the bronchodilating effect). MgSO4 resulted in a significant decrease of peak airway pressure (43.0 +/- 6.8 to 32.0 +/- 8.0 cmH2O) and inspiratory flow resistance (22.7 +/- 7.0 to 11.9 +/- 6.0 cmH2O.l-1.s-1) within 1 h. The resulting serum magnesium levels after one hour were up to threefold of the normal serum levels. Although a maintainance dose of 0.4 g/h had been administered continuously during the following 24 h serum magnesium decreased towards normal values within this time. The only relevant side-effect was a mild to moderate arterial hypotension in two of the five patients during the high dose administration period of MgSO4 which responded readily to dopamine treatment.