Prognosis
The survival rate of people who receive initial emergency care by ambulance is only 2%, with 15% experiencing return of spontaneous circulation. However, with defibrulation within 3-5 minutes, the survival rate increases to 30%.
Since mortality in case of OHCA is high, programs were developed to improve survival rate. Although mortality in case of ventricular fibrillation is high, rapid intervention with a defibrillator increases survival rate.
Survival is mostly related to the cause of the arrest (see above). In particular, patients who have suffered hypothermia have an increased survival rate, possibly because the cold protects the vital organs from the effects of tissue hypoxia. Survival rates following an arrest induced by toxins is very much dependent on identifying the toxin and administering an appropriate antidote. A patient who has suffered a myocardial infarction due to a blood clot in the left coronary artery has a lower chance of survival.
A study of survival rates from out of hospital cardiac arrest found that 14.6% of those who had received resuscitation by ambulance staff survived as far as admission to hospital. Of these, 59% died during admission, half of these within the first 24 hours, while 46% survived until discharge from hospital. This gives us an overall survival following cardiac arrest of 6.8%. Of these 89% had normal brain function or mild neurological disability, 8.5% had moderate impairment, and 2% suffered major neurological disability. Of those who were discharged from hospital, 70% were still alive 4 years later.
A specific pattern of the brain damage in cardiac arrest survivors revealed by MRI study has been known as a delayed T1-hyperintensity localized in the striatum, cerebral cortex, thalamus, and/or substantia nigra (Fujioka, M. et al. Stroke. 1994;25:2091-2095.; Fujioka, M. et al. Neuroradiology. 1994;36:605-607.). The MRI volumetric study demonstrated that the human hippocampus showed its selective atrophy in a delayed fashion after cardiopulmonary resuscitation (Fujioka, M. et al. Cerebrovasc Dis. 2000;10:2-7.).
A review into prognosis following in-hospital cardiac arrest found a survival to discharge of 14% although the range between different studies was 0-28%.
Read more about this topic: Cardiac Arrest