Does Intravenous Magnesium Benefit Patients of Cardiac Arrest? a Meta-Analysis

Objective Evidence shows that magnesium has anti-arrhythmic roles. However, clinical trials suggest that there are conflicting outcomes of cardiac arrest patients given magnesium. The study aimed to examine the effects of magnesium sulfate therapy on cardiac arrest patients using a meta-analysis. Methods We searched the MEDLINE (1966-July 2011), OVID (1980-July 2011), EMBASE (1980-July 2011), Chinese bio-medical literature & retrieval system (1978-July 2011), Chinese medical current contents (1995-July 2011), and Chinese medical academic conference (1994-July 2011). Studies were included if (1) the study design was a randomised controlled trial (RCT); (2) the study population included cardiac arrest patients who received cardiopulmonary resuscitation and either intravenous magnesium or placebo (0.9% normal saline); (3) the study provided data on return of spontaneous circulation (ROSC) and survival to hospital discharge. Relative risk (RR) and 95% confidence interval (CI) were used to pool the effect. Results The study included six RCTs with a total of 531 participants from cardiac arrest. The pooled data demonstrated that ROSC and hospital discharge rates in patients treated with magnesium were 35.5% (95% CI=29.7%-41.3%) and 10.4% (95% CI=6.7%-14.1%) compared with placebo (ROSC rate: 31.3%, 95% CI=25.8%-36.8%; hospital discharge rate: 8.5%, 95% CI=5.2%-11.8%). Administration of intravenous magnesium sulfate could not significantly increase ROSC (RR=1.14, 95% CI=0.91-1.43, P=0.26) and survival to hospital discharge (RR=1.22, 95% CI=0.74-2.02, P=0.43) compared with placebo. Conclusions Administration of magnesium sulfate does not improve ROSC and survival to hospital discharge in patients of cardiac arrest.