Cardiac arrest: no clear benefit from magnesium for in-patients

Clinical bottom line (level 1b-)

  1. In-patients with a cardiac arrest who received magnesium compared with placebo were not clearly more likely to regain spontaneous circulation or survive to discharge.
Thel et al: Lancet 1997; 350: 1272-1276
Expires November 2003

The study

Double-blinded ?concealed randomised trial with intention-to-treat
Setting: university hospital, USA

156 patients (aged mean 65, 57% male) with an in-hospital cardiac arrest (absence of spontaneous respiration and pulse)

Excluded if
  • clinical indication for magnesium (torsade de pointes)
  • neuromuscular junction disorders
  • signs of irreversible death (rigor mortis, severe hypothermia (< 26.6 C), or an estimated 30 minutes between death and discovery
  • cardiac arrest in emergency department, operating rooms and recovery rooms
  • advanced atrioventricular nodal heart block
  • serum creatinine > 354 micromol/l
  • aged < 18


    • Note:
  • Patients were treated using ACLS guidelines.


    • Control Group: (n = 80, 80 analysed): placebo
    Experimental Group: (n = 76, 76 analysed): magnesium 2g (8 mmol) bolus iv followed by a 2 g infusion over 24 hours

    100% followed for ? length of hospital stay
    Outcome notes:
    • survival to 24 hours : 24 hours
    • survival to discharge : to discharge

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    return of spontaneous circulation unknown 48
    (60.0%)    		 41
    (54.0%)    		 -10%
    (-32% to 18%)    		 -6.05%
    (-21.6% to 9.47%)    		 -17
    (NNT = 11 to infinity;
    NNH = 5 to infinity)
    survival to 24 hours unknown 40
    (50.0%)    		 33
    (43.4%)    		 -13%
    (-38% to 22%)    		 -6.58%
    (-22.2% to 9.05%)    		 -15
    (NNT = 11 to infinity;
    NNH = 5 to infinity)
    survival to discharge unknown 17
    (21.3%)    		 16
    (21.1%)    		 -1%
    (-46% to 82%)    		 -0.20%
    (-13.0% to 12.6%)    		 -510
    (NNT = 8 to infinity;
    NNH = 8 to infinity)

    Comments

    1. The study is too small to show any difference between the two groups.

    Citation

    1. Thel MC, Armstrong AL, McNulty SE, et al: randomised trial of magnesium in in-hospital cardiac arrest. Lancet 1997; 350: 1272-1276
    Search Terms: arrest and magnesium in Cochrane
    Contributor: Chris Ball and Clare Wotton, November 1999
    Reviewer: Roy Poses

    Clinical Question.
    Patient in-hospital cardiac arrest
    Intervention or Exposure magnesium
    Comparison placebo
    Outcome survival