Cardiac arrest: automatic defibrillators were less effective than manual

Clinical bottom line (level 2b)

  1. Patients in cardiac arrest who received automatic defibrillation compared with manual were less likely to reach hospital alive (NNH = 10 at unknown) .
  2. There was no clear effect on the number of patients discharged alive from hospital.
Cummins et al: Journal of the American Medical Association 1987; 257: 1605-1610
Expires October 2003

The study

Unblinded unconcealed quasi-randomised trial with intention-to-treat
Setting: urban county, USA

321 patients (aged mean 64, 70% male) in verified cardiac arrest

Excluded if
  • time between emergency medical technician and paramedic arriving on scene less than 2 minutes
  • arrest due to trauma


    • Control Group: (n = 158, 158 analysed): manual defibrillation
    Experimental Group: (n = 163, 163 analysed): automatic defibrillation using Heart Aid Model 95
    Resuscitation protocols were otherwise similar.
    100% followed for ? to discharge

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNH
    (95% CI)
    admitted alive unknown 55
    (34.8%)    		 40
    (24.5%)    		 -16%
    (-34% to 0%)    		 -10.27%
    (-20.21% to -0.33%)    		 10
    (-303 to -5)
    discharged alive unknown 23
    (14.6%)    		 18
    (11.0%)    		 -4%
    (-13% to 4%)    		 -3.51%
    (-10.8% to 3.79%)    		 28
    (NNT = 9 to infinity;
    NNH = 26 to infinity)

    Comments

    1. Emergency medical technicians were more experienced with manual defibrillation than automatic - this may explain some of the differences noted. The great advantage of AED's is that they can be used by emergency personnel and even lay persons with little training.
    2. The study was too small to show any difference between the two groups for discharge alive from hospital.
    3. Emergency medical technicians switched defibrillators every 75 days for six sessions.

    Citation

    1. Cummins RO, Eisenberg MS, Litwin PE: Automatic external defibrillators used by emergency medical technicians: a controlled clinical trial. Journal of the American Medical Association 1987; 257: 1605-1610
    Contributor: Chris Ball and Musab Hayatli, October 1999
    Reviewer: Kenneth Ballew

    Clinical Question.
    Patient cardiac arrest
    Intervention or Exposure automatic defibrillation
    Comparison manual defibrillation
    Outcome mortality