Thirty children (age 6-17.9) experiencing a moderate-severe asthma
exacerbation who failed to improve significantly after three NMTs
were randomized in a double blind fashion to receive 40mg/kg IV
MgSO4 (16 patients) or similar volume of normal saline (14 patients).(1)
The study excluded patients who had fever, recent use of theophyline,
cardiac, renal or pulmonary disease other than asthma. Patients
under the age of six or who were too severely distressed to perform
PFTs were also excluded.
All patients in the treatment and control groups were similar
(see table 1) The only significant difference between the two
groups was slightly higher systolic blood pressure in the MgSO4
All patients were treated equally other than the MgSO4 treatment.
Each patient received three NMTs (albuterol, atrovent, or combination)
and continued to have PEFR < 70% predicted. All patients received
2mg/kg IV methylprednisolone, and continued to receive NMTs at
the discretion of the ED team.
The PEFR, FEV1, and FVC all improved significantly in the MgSO4
treatment group compared with the control group. The improvements
were noted immediately after completing the MgSO4 infusion, and
continued to improve throughout the study.
None of the patients in the MgSO4 treatment group were admitted
to the hospital. In the control group 7/14 patients required admission
to the hospital. (ARR 0.5, NNT 2)
There were no changes in blood pressure or other significant side
effects in the MgSO4 treated group.