Cardiac arrest is the cessation of purposeful blood pumping by the heart, which is invariably fatal if not reversed by cardio-pulmonary resuscitation (CPR), usually requiring [[Advanced Cardiac Life Support]. Electrical activity of the heart does not necessarily cease; it may simply not stimulate the cardiac musclature, as in electromechanical dissociation (EMD), or ineffectively stimulate it, as in ventricular fibrillation (VF). VF, indeed, is the most common rhythm seen in emergency medicine.
Basic CPR, with closed-chest compressions and possibly rescue breathing, rarely reverses adult arrest, but is a potentially life-saving intervention that buys time for more advanced interventions, such as electrical defibrillation to reverse VF. ACLS is most likely to be effective, although with a much lower success rate than popular perception, with metabolically related arrests. Arrests caused by trauma have a much more dismal prognosis, although heroic, highly-skilled interventions such as opening the chest and manually compressing the heart can work in some cases, usually with massive fluid replacement. Cardiac arrest caused by blunt chest trauma is considered irreversible by most trauma physicians.
Terminology in this area can be confusing. Heart failure does not mean the heart has literally stopped, but is a spectrum of degradations in pumping function. Terminal heart failure can lead to cardiac arrest. A subset of arrests are of the form of sudden cardiac death, which, despite the name, has one of the better chances of resuscitation; it is often due to VF.
Cardio Pulmonary Resuscitation
Patients surviving cardiac arrest who cannot follow commands or who are comatose, may have increased chance of favorable neurological outcome if their body temperature is cooled to 32 to 34 degrees centigrade.
- ECC Committee, Subcommittees and Task Forces of the American Heart Association (2005). "2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.". Circulation 112 (24 Suppl): IV1-203. DOI:10.1161/CIRCULATIONAHA.105.166550. PMID 16314375. Research Blogging.
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- Kim YM, Yim HW, Jeong SH, Klem ML, Callaway CW (2012). "Does therapeutic hypothermia benefit adult cardiac arrest patients presenting with non-shockable initial rhythms?: A systematic review and meta-analysis of randomized and non-randomized studies.". Resuscitation 83 (2): 188-96. DOI:10.1016/j.resuscitation.2011.07.031. PMID 21835145. Research Blogging.
- Hypothermia after Cardiac Arrest Study Group (2002). "Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest.". N Engl J Med 346 (8): 549-56. DOI:10.1056/NEJMoa012689. PMID 11856793. Research Blogging. Review in: ACP J Club. 2002 Sep-Oct;137(2):46 Review in: Evid Based Nurs. 2002 Oct;5(4):111
- Bernard SA, Gray TW, Buist MD, Jones BM, Silvester W, Gutteridge G et al. (2002). "Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia.". N Engl J Med 346 (8): 557-63. DOI:10.1056/NEJMoa003289. PMID 11856794. Research Blogging.