BACKGROUND: Intravenous magnesium sulfate (MgSO(4)) in children and adults with refractory acute asthma is effective, but therapy may be limited by systemic hypotension that might be avoided with the aerosol route. Inhaled MgSO(4) has a relatively high dose (volume) requirement. This, plus the use of inefficient delivery systems, may explain the lack of efficacy of inhaled MgSO(4) in some studies. An in vitro study suggested that the AeroNeb Go with the Idehaler Pocket and a face mask would deliver 16 mg/min of MgSO(4) to the respiratory system in older children, and approximately a fifth for toddlers, but no in vivo data exist. METHODS: Saline mixed with a radiolabel was used as a proxy for the 100 mg/mL MgSO(4) solution. In 5 adult males the rate of deposition was measured using nuclear medicine techniques. The radiolabel deposition below the vocal cords was converted to the rate of deposition of MgSO(4) and compared to the results from an in vitro model using adult respiratory patterns. RESULTS: The mean ± SD rate of deposition was 12.6 ± 1.9 mg/min. The reasons for this lower deposition, compared to the in vitro estimate, was most likely the exhalation of anatomical dead space aerosol, which would have been captured on the inspiratory filter in vitro. CONCLUSIONS: These in vivo data confirm the deposition data predicted in the in vitro study, although caution should be used in extrapolating the results to children. This device appears suitable for the clinical trial of inhaled MgSO(4) in children and adults with refractory asthma.
BACKGROUND: Intravenous magnesium sulfate (MgSO(4)) in children and adults with refractory acute asthma is effective, but therapy may be limited by systemic hypotension that might be avoided with the aerosol route. Inhaled MgSO(4) has a relatively high dose (volume) requirement. This, plus the use of inefficient delivery systems, may explain the lack of efficacy of inhaled MgSO(4) in some studies. An in vitro study suggested that the AeroNeb Go with the Idehaler Pocket and a face mask would deliver 16 mg/min of MgSO(4) to the respiratory system in older children, and approximately a fifth for toddlers, but no in vivo data exist. METHODS:Saline mixed with a radiolabel was used as a proxy for the 100 mg/mL MgSO(4) solution. In 5 adult males the rate of deposition was measured using nuclear medicine techniques. The radiolabel deposition below the vocal cords was converted to the rate of deposition of MgSO(4) and compared to the results from an in vitro model using adult respiratory patterns. RESULTS: The mean ± SD rate of deposition was 12.6 ± 1.9 mg/min. The reasons for this lower deposition, compared to the in vitro estimate, was most likely the exhalation of anatomical dead space aerosol, which would have been captured on the inspiratory filter in vitro. CONCLUSIONS: These in vivo data confirm the deposition data predicted in the in vitro study, although caution should be used in extrapolating the results to children. This device appears suitable for the clinical trial of inhaled MgSO(4) in children and adults with refractory asthma.
Authors: Suzanne Schuh; Judy Sweeney; Maggie Rumantir; Allan L Coates; Andrew R Willan; Derek Stephens; Eshetu G Atenafu; Yaron Finkelstein; Graham Thompson; Roger Zemek; Amy C Plint; Jocelyn Gravel; Francine M Ducharme; David W Johnson; Karen Black; Sarah Curtis; Darcy Beer; Terry P Klassen; Darcy Nicksy; Stephen B Freedman Journal: JAMA Date: 2020-11-24 Impact factor: 56.272
Authors: Suzanne Schuh; Judy Sweeney; Stephen B Freedman; Allan L Coates; David W Johnson; Graham Thompson; Jocelyn Gravel; Francine M Ducharme; Roger Zemek; Amy C Plint; Darcy Beer; Terry Klassen; Sarah Curtis; Karen Black; Darcy Nicksy; Andrew R Willan Journal: Trials Date: 2016-05-24 Impact factor: 2.279
Authors: Suzanne Schuh; Stephen B Freedman; Roger Zemek; Amy C Plint; David W Johnson; Francine Ducharme; Jocelyn Gravel; Graham Thompson; Sarah Curtis; Derek Stephens; Allan L Coates; Karen J Black; Darcy Beer; Judy Sweeney; Maggie Rumantir; Yaron Finkelstein Journal: JAMA Netw Open Date: 2021-07-01