Editing Cardiac arrest (section)

== Prevention ==

=== Primary prevention ===
With the lack of positive outcomes following cardiac arrest, efforts have been spent finding effective strategies to prevent cardiac arrest events. The approach to primary prevention promotes a [[healthy diet]], [[exercise]], limited alcohol consumption, and [[smoking cessation]].<ref name="NHLBI-2016" />

Exercise is an effective preventative measure for cardiac arrest in the general population but may be risky for those with pre-existing conditions.<ref name="Fanous-2019">{{cite journal |vauthors=Fanous Y, Dorian P |date=July 2019 |title=The prevention and management of sudden cardiac arrest in athletes |journal=CMAJ |volume=191 |issue=28 |pages=E787–E791 |doi=10.1503/cmaj.190166 |pmc=6629536 |pmid=31308007}}</ref> The risk of a transient catastrophic cardiac event increases in individuals with heart disease during and immediately after exercise.<ref name="Fanous-2019" /> The lifetime and acute risks of cardiac arrest are decreased in people with heart disease who perform regular exercise, perhaps suggesting the benefits of exercise outweigh the risks.<ref name="Fanous-2019" />

A 2021 study found that diet may be a modifiable risk factor for a lower incidence of sudden cardiac death.<ref name="Shikany-2021">{{cite journal | vauthors = Shikany JM, Safford MM, Soroka O, Brown TM, Newby PK, Durant RW, Judd SE | title = Mediterranean Diet Score, Dietary Patterns, and Risk of Sudden Cardiac Death in the REGARDS Study | journal = Journal of the American Heart Association | volume = 10 | issue = 13 | pages = e019158 | date = July 2021 | pmid = 34189926 | pmc = 8403280 | doi = 10.1161/JAHA.120.019158 }}</ref> The study found that those who fell under the category of having "Southern [United States] diets" representing those of "added fats, fried food, eggs, organ and processed meats, and sugar-sweetened beverages" had a positive association with an increased risk of cardiac arrest, while those deemed following the "[[Mediterranean diet]]s" had an inverse relationship regarding the risk of cardiac arrest.<ref name="Shikany-2021"/> According to a 2012 review published, omega-3 PUFA supplementation is not associated with a lower risk of sudden cardiac death.<ref name="Rizos-2012">{{cite journal|vauthors=Rizos EC, Ntzani EE, Bika E, Kostapanos MS, Elisaf MS|date=September 2012|title=Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: a systematic review and meta-analysis|journal=JAMA|volume=308|issue=10|pages=1024–1033|doi=10.1001/2012.jama.11374|pmid=22968891}}</ref>

A [[Cochrane review]] published in 2016 found moderate-quality evidence to show that blood pressure-lowering drugs do not reduce the risk of sudden cardiac death.<ref>{{cite journal |vauthors=Taverny G, Mimouni Y, LeDigarcher A, Chevalier P, Thijs L, Wright JM, Gueyffier F |date=March 2016 |title=Antihypertensive pharmacotherapy for prevention of sudden cardiac death in hypertensive individuals |journal=The Cochrane Database of Systematic Reviews |volume=2016 |issue=3 |pages=CD011745 |doi=10.1002/14651858.CD011745.pub2 |pmc=8665834 |pmid=26961575}}</ref>

In certain high-risk patient populations, [[implantable cardioverter-defibrillator]]s (ICD) are also used to prevent sudden cardiac death.<ref name="Shun-Shin-2017" /> Such conditions include the inherited arrhythmias (long QT syndrome, Brugada syndrome, etc) and heart failure.

===Secondary prevention===
[[File:Blausen 0543 ImplantableCardioverterDefibrillator.svg|upright=1.3|thumb|Illustration of an [[implantable cardioverter-defibrillator]] (ICD)]]
An [[implantable cardioverter-defibrillator]] (ICD) is a battery-powered device that monitors electrical activity in the heart, and when an arrhythmia is detected, can deliver an electrical shock to terminate the abnormal rhythm. ICDs are used to prevent sudden cardiac death (SCD) in those who have survived a prior episode of sudden cardiac arrest (SCA) due to ventricular fibrillation or ventricular tachycardia.<ref name="Epstein-2008">{{cite journal|display-authors=6|vauthors=Epstein AE, DiMarco JP, Ellenbogen KA, Estes NA, Freedman RA, Gettes LS, Gillinov AM, Gregoratos G, Hammill SC, Hayes DL, Hlatky MA, Newby LK, Page RL, Schoenfeld MH, Silka MJ, Stevenson LW, Sweeney MO, Smith SC, Jacobs AK, Adams CD, Anderson JL, Buller CE, Creager MA, Ettinger SM, Faxon DP, Halperin JL, Hiratzka LF, Hunt SA, Krumholz HM, Kushner FG, Lytle BW, Nishimura RA, Ornato JP, Page RL, Riegel B, Tarkington LG, Yancy CW|date=May 2008|title=ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices): developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons|journal=Circulation|volume=117|issue=21|pages=e350–e408|doi=10.1161/CIRCUALTIONAHA.108.189742|pmid=18483207|doi-access=free}}</ref>

Numerous studies have been conducted on the use of ICDs for the secondary prevention of SCD. These studies have shown improved survival with ICDs compared to the use of anti-arrhythmic drugs.<ref name="Epstein-2008" /> ICD therapy is associated with a 50% [[relative risk reduction]] in death caused by an arrhythmia and a 25% relative risk reduction in all-cause mortality.<ref>{{cite journal|display-authors=6|vauthors=Connolly SJ, Hallstrom AP, Cappato R, Schron EB, Kuck KH, Zipes DP, Greene HL, Boczor S, Domanski M, Follmann D, Gent M, Roberts RS|date=December 2000|title=Meta-analysis of the implantable cardioverter defibrillator secondary prevention trials. AVID, CASH and CIDS studies. Antiarrhythmics vs Implantable Defibrillator study. Cardiac Arrest Study Hamburg . Canadian Implantable Defibrillator Study|journal=European Heart Journal|volume=21|issue=24|pages=2071–2078|doi=10.1053/euhj.2000.2476|pmid=11102258|doi-access=free}}</ref>

Prevention of SCD with ICD therapy for high-risk patient populations has similarly shown improved survival rates in several large studies. The high-risk patient populations in these studies were defined as those with severe [[ischemic cardiomyopathy]] (determined by a reduced [[Ejection fraction|left ventricular ejection fraction]] (LVEF)). The LVEF criteria used in these trials ranged from less than or equal to 30% in MADIT-II to less than or equal to 40% in MUSTT.<ref name="Epstein-2008" /><ref name="Shun-Shin-2017">{{cite journal |vauthors=Shun-Shin MJ, Zheng SL, Cole GD, Howard JP, Whinnett ZI, Francis DP |date=June 2017 |title=Implantable cardioverter defibrillators for primary prevention of death in left ventricular dysfunction with and without ischaemic heart disease: a meta-analysis of 8567 patients in the 11 trials |journal=European Heart Journal |volume=38 |issue=22 |pages=1738–1746 |doi=10.1093/eurheartj/ehx028 |pmc=5461475 |pmid=28329280}}</ref>

Alternatively, a [[wearable cardioverter defibrillator]] (eg, LifeVest) can be used instead of an implantable defibrillator, and the wearable option can be used as a temporary bridge to an implantable device. Such instances are [[endocarditis]] where an implantable device is at high risk of becoming infected if implanted too soon.

===Crash teams===
In hospital, a cardiac arrest is referred to as a "crash", or a "code". This typically refers to [[code blue]] on the [[hospital emergency codes]]. A dramatic drop in vital sign measurements is referred to as "coding" or "crashing", though coding is usually used when it results in cardiac arrest, while crashing might not. Treatment for cardiac arrest is sometimes referred to as "calling a code".

Patients in general wards often deteriorate for several hours or even days before a cardiac arrest occurs.<ref name="Resuscitation Council" /><ref name="Kause-2004">{{cite journal |vauthors=Kause J, Smith G, Prytherch D, Parr M, Flabouris A, Hillman K |date=September 2004 |title=A comparison of antecedents to cardiac arrests, deaths and emergency intensive care admissions in Australia and New Zealand, and the United Kingdom--the ACADEMIA study |journal=Resuscitation |volume=62 |issue=3 |pages=275–282 |doi=10.1016/j.resuscitation.2004.05.016 |pmid=15325446}}</ref> This has been attributed to a lack of knowledge and skill amongst ward-based staff, in particular, a failure to measure the [[respiratory rate]], which is often the major predictor of a deterioration<ref name="Resuscitation Council" /> and can often change up to 48 hours prior to a cardiac arrest. In response, many hospitals now have increased training for ward-based staff. A number of "early warning" systems also exist that aim to quantify the person's risk of deterioration based on their [[vital signs]] and thus provide a guide to staff. In addition, specialist staff are being used more effectively to augment the work already being done at the ward level. These include:
* Crash teams (or code teams) – These are designated staff members with particular expertise in resuscitation who are called to the scene of all arrests within the hospital. This usually involves a specialized cart of equipment (including a [[defibrillation|defibrillator]]) and drugs called a "[[crash cart]]" or "crash trolley".
* [[Medical emergency team]]s – These teams respond to all emergencies with the aim of treating people in the acute phase of their illness in order to prevent a cardiac arrest. These teams have been found to decrease the rates of in-hospital cardiac arrest (IHCA) and improve survival.<ref name="Kronick-2015" />
* Critical care outreach – In addition to providing the services of the other two types of teams, these teams are responsible for educating non-specialist staff. In addition, they help to facilitate transfers between [[Intensive care unit|intensive care/high dependency units]] and the general hospital wards. This is particularly important as many studies have shown that a significant percentage of patients discharged from critical care environments quickly deteriorate and are re-admitted; the outreach team offers support to ward staff to prevent this from happening.{{citation needed|date=December 2017}}