Comparison of Two High-Dose Magnesium Infusion Regimens in the Treatment of Status Asthmaticus

Continuous Magnesium Sulfate Infusions for Status Asthmaticus in Children: A Systematic Review

OBJECTIVES

Magnesium sulfate is a second-tier therapy for asthma exacerbations in children; guidelines recommend a single-dose to improve pulmonary function and decrease the odds of admission to the in-patient setting. However, many clinicians utilize prolonged magnesium sulfate infusions for children with refractory asthma. The purpose of this review is to describe the efficacy and safety of magnesium sulfate infusions administered over ≥ 1 h in children with status asthmaticus.

METHODS

Medline was searched using the keywords "magnesium sulfate" and "children." Articles evaluating the use of magnesium sulfate infusions for ≥1 h published between 1946 and August 2021 were included. Published abstracts were not included because of lack of essential details. All articles were screened by two reviewers.

RESULTS

Eight reports including 447 children were included. The magnesium regimens evaluated included magnesium delivered over 1 h (n = 148; 33.1%), over 4-5 h (n = 105; 23.5%), and over >24 h (n = 194; 43.4%). Majority of patients received a bolus dose of 25-75 mg/kg/dose prior to initiation of a prolonged infusion (n = 299; 66.9%). For the patients receiving magnesium infusions over 4-5 h, the dosing regimen varied between 40 and 50 mg/kg/h. For those receiving magnesium infusions >24 h, the dosing varied between 18.4 and 25 mg/kg/h for a duration between 53.4 and 177.5 h. Only three reports including 186 patients (41.6%) included an evaluation of clinical outcomes including evaluation of lung function parameters, reduction in PICU transfers, and/or decrease in emergency department length of stay. Five reports including 261 patients (58.4%) evaluated magnesium serum concentrations. In most reports, the goal concentrations were between 4 and 6 mg/dL. Only 3 (1.1%) out of the 261 patients had supratherapeutic magnesium concentrations. The only reports finding adverse events attributed to magnesium were noted in those receiving infusions for >24 h. Clinically significant adverse events included hypotension (n = 74; 16.6%), nausea/vomiting (n = 35; 7.8%), mild muscle weakness (n = 22; 4.9%), flushing (n = 10; 2.2%), and sedation (n = 2; 0.4%).

CONCLUSION

Significant variability was noted in magnesium dosing regimens, with most children receiving magnesium infusions over >4 h. Most reports did not assess clinical outcomes. Until future research is conducted, the use of prolonged magnesium sulfate infusions should be reserved for refractory asthma therapy.

Efficacy and Safety of Prolonged Magnesium Sulfate Infusions in Children With Refractory Status Asthmaticus

OBJECTIVES

There is a paucity of data on the use of intravenous magnesium sulfate infusion in children with refractory status asthmaticus. The purpose of this study was to evaluate the efficacy and safety of prolonged magnesium sulfate infusion as an advanced therapy.

METHODS

This is a single center retrospective study of children admitted to our pediatric intensive care unit (PICU) with status asthmaticus requiring continuous albuterol. Treatment group included patients receiving magnesium for ≥4 h and control group included those on other therapies only. Patients were matched 1:4 based on age, sex, obesity, pediatric index of mortality III and pediatric risk of mortality III scores. Primary outcomes included PICU length of stay (LOS) and mechanical ventilation (MV) requirement. Secondary outcomes included mortality, extracorporeal membrane oxygenation (ECMO) requirement, analyses of factors associated with PICU LOS and MV requirement and safety of magnesium infusion. Logistic and linear regressions were employed to determine factors associated with MV requirement and PICU LOS, respectively.

RESULTS

Treatment and control groups included 27 and 108 patients, respectively. Median initial infusion rate was 15 mg/kg/hour, with median duration of 28 h. There was no difference in the MV requirement between the treatment and control groups [7 (25.9%) vs. 20 patients (18.5%), p = 0.39]. Median PICU LOS and ECMO use were significantly higher in treatment vs. control group [(3.63 vs. 1.09 days, p < 0.01) and (11.1 vs. 0%, p < 0.01), respectively]. No mortality difference was noted. On regression analysis, patients receiving ketamine and higher prednisone equivalent dosing had higher odds of MV requirement [OR 19.29 (95% CI 5.40-68.88), p < 0.01 and 1.099 (95% CI 1.03-1.17), p < 0.01, respectively]. Each mg/kg increase in prednisone equivalent dosing corresponded to an increase in PICU LOS by 0.13 days (95% CI 0.096-0.160, p < 0.01). Magnesium infusions were not associated with lower MV requirement or lower PICU LOS after controlling for covariates. Fourteen (51.9%) patients in the treatment group had an adverse event, hypotension being the most common.

CONCLUSION

Magnesium sulfate infusions were not associated with MV requirement, PICU LOS or mortality.