Effectiveness of calcium administration in maternal cardiac arrest associated with hypermagnesemia: A scoping review

Aim: This study aimed to clarify whether calcium administration has a therapeutic effect against cardiac arrest resulting from magnesium toxicity in pregnant or puerperal women, and to determine whether the body of evidence published to date suggests the need for a systematic review. Methods: This review was guided by a specific methodological framework and Preferred Reporting Items for Systematic reviews and Meta-Analysis extension for Scoping Reviews. Literature published up to September 24, 2020 was searched using the Medline database. Eligible articles included peer-reviewed studies in humans that prospectively or retrospectively evaluated the effects of calcium therapy on clinical outcomes and had an English abstract. Two reviewers independently screened the search results and extracted data from analyzed studies. Results: Nineteen references were screened, and nine studies were analyzed. Five studies described maternal cardiac arrest or hypotension due to hypermagnesemia, and two studies described cardiac arrest in non-pregnant women due to hypermagnesemia. The remaining two articles were guidelines that described calcium administration for hypermagnesemia. We did not identify high-quality or large-sample studies which are needed to perform a systematic review. Conclusions: The identified studies were insufficient to change existing recommendations. However, calcium administration may be considered for cardiac arrest associated with hypermagnesemia if ready to be performed during cardiopulmonary resuscitation.