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| {{SI}} | | __NOTOC__ |
| | {{Anoxic brain injury}} |
| | '''For patient information, click [[Anoxic brain injury (patient information)|here]]''' |
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| {{CMG}} | | {{CMG}}; '''Associate Editors-In-Chief:''' [[Varun Kumar]], M.B.B.S.; [[Lakshmi Gopalakrishnan]], M.B.B.S. |
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| '''Associate Editors-In-Chief:''' [[Varun Kumar]], M.B.B.S.; [[Lakshmi Gopalakrishnan]], M.B.B.S.
| | {{SK}} Hypoxic brain injury; post cardiac arrest syndrome |
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| ==Overview== | | ==[[Anoxic brain injury overview|Overview]]== |
| Anoxic or hypoxic brain injury is often seen after [[cardiac arrest]]. Major efforts are underway to improve "The Chain of Survival" based upon early access to medical care, early defibrillation, early [[CPR]] and early hospital care. Therapeutic [[hypothermia]] may improve outcomes. Steroids, [[manitol]], [[diuresis]] and [[hyperventilation]] have not been documented to meaningfully improve clinical outcomes. | |
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| ==Epidemiology== | | ==[[Anoxic brain injury pathophysiology|Pathophysiology]]== |
| In a 1990s study from the UK, resuscitation for cardiac arrest was attempted in 10,081 patients. Of these only 1476 (14.6%) survived to be admitted to the hospital <ref name="pmid15333549">{{cite journal |author=Lyon RM, Cobbe SM, Bradley JM, Grubb NR |title=Surviving out of hospital cardiac arrest at home: a postcode lottery? |journal=Emerg Med J |volume=21 |issue=5 |pages=619–24 |year=2004 |month=September |pmid=15333549 |pmc=1726412 |doi=10.1136/emj.2003.010363 |url=}}</ref><ref name="pmid8664715">{{cite journal |author=Cobbe SM, Dalziel K, Ford I, Marsden AK |title=Survival of 1476 patients initially resuscitated from out of hospital cardiac arrest |journal=BMJ |volume=312 |issue=7047 |pages=1633–7 |year=1996 |month=June |pmid=8664715 |pmc=2351362 |doi= |url=http://bmj.com/cgi/pmidlookup?view=long&pmid=8664715}}</ref>. Of these small number of patients who survived to admission, 59.3% died during that admission, half of these within the first 24 hours. 46.1% survived to hospital discharge (this is 6.75% of those who had been resuscitated by ambulance staff). Of those who were successfully discharged from hospital, 70% were still alive 4 years after their discharge.
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| ==Predictors of Survival== | | ==[[Anoxic brain injury causes|Causes]]== |
| ===Improved Prognosis with In-Hospital versus Out-of-Hospital Cardiac Arrest=== | | ==[[Anoxic brain injury differential diagnosis|Differentiating Anoxic brain injury from other Diseases]]== |
| Out-of-hospital cardiac arrest (OHCA) has a worse survival rate (2-8% survival at discharge) than in-hospital cardiac arrest (15% survival at discharge).
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| ===Improved Prognosis with VT/VF versus PEA or Asystole=== | | ==[[Anoxic brain injury epidemiology and demographics|Epidemiology and Demographics]]== |
| A major determining factor in survival is the initially documented electrocardiographic rhythm. Patients with [[ventricular fibrilation]] ([[VF]]) or [[ventricual tachycardia]] ([[VT]]) (aka VT/VF) have a 10-15 fold greater chance of survival than patients with [[pulseless electrical activity]] ([[PEA]]) or [[asystole]]. VT and VF are responsive to [[defibrillation]], whereas asystole and PEA are not.
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| ===Rapid Defibrillation is Associated with Imporved Survival=== | | ==[[Anoxic brain injury natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
| Rapid intervention with a [[defibrillator]] increases survival rates.<ref>{{cite journal |author=Eisenberg MS, Mengert TJ |title=Cardiac resuscitation |journal=N. Engl. J. Med. |volume=344 |issue=17 |pages=1304–13 |year=2001 |month=April |pmid=11320390 |doi= |url=http://content.nejm.org/cgi/pmidlookup?view=short&pmid=11320390&promo=ONFLNS19}}</ref><ref name="pmid12826637">{{cite journal |author=Bunch TJ, White RD, Gersh BJ, ''et al'' |title=Long-term outcomes of out-of-hospital cardiac arrest after successful early defibrillation |journal=N. Engl. J. Med. |volume=348 |issue=26 |pages=2626–33 |year=2003 |month=June |pmid=12826637 |doi=10.1056/NEJMoa023053 |url=}}</ref>
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| ==Incidence and Predictors of Entering Into a Vegetative State versus Making a Full Recovery== | | ==Diagnosis== |
| Cardiac arrest is the third leading cause of [[coma]]. Approximately 80% of patients who suffered a cardiac arrest who survived to be admitted to the hospital will be in coma for varying lengths of time. Of these patients, approximately 40% will enter into a persistent vegetative state and 80% die within 1 year. In contrast, those rare patients who survive until discharge without significant neurological impairment can expect a fair to good quality of life.
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| The duration of hypoxia/ischemia determines the extent of neuronal injury i.e. in patients who suffer hypoxia for less than 5 minutes, are less likely to have permanent neurologic deficits, while with prolonged, global hypoxia, patients may develop [[myoclonus]] or a persistent [[vegetative state]].<ref name="pmid16363390">{{cite journal |author=Mellion ML |title=Neurologic consequences of cardiac arrest and preventive strategies |journal=[[Medicine and Health, Rhode Island]] |volume=88 |issue=11 |pages=382–5 |year=2005 |month=November |pmid=16363390 |doi= |url=}}</ref>
| | [[Anoxic brain injury history and symptoms|History and Symptoms]] | [[Anoxic brain injury physical examination|Physical Examination]] | [[Anoxic brain injury laboratory findings|Laboratory Findings]] | [[Anoxic brain injury CT|CT]] | [[Anoxic brain injury MRI|MRI]] | [[Anoxic brain injury echocardiography or ultrasound|Echocardiography or Ultrasound]] | [[Anoxic brain injury electroencephalogram|Electroencephalogram]] | [[Anoxic brain injury other diagnostic studies|Other Diagnostic Studies]] |
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| The duration of coma is an important predictor of the recovery of neurologic function. In a 1979 study of 181 cardiac arrest patients who survived to hospital admission, 84% were comatose for more than 1 hour and 56% were comatose for more than 24 hours<ref name="pmid442945">{{cite journal |author=Thomassen A, Wernberg M |title=Prevalence and prognostic significance of coma after cardiac arrest outside intensive care and coronary units |journal=[[Acta Anaesthesiologica Scandinavica]] |volume=23 |issue=2 |pages=143–8 |year=1979 |month=April |pmid=442945 |doi= |url=}}</ref>. There was minimal neurologic deficit if coma lasted less than 24 hours. However, among the 85 patients who were comatose for more than 24 hours, only 7 of them were discharged alive. The severity of neurological impairment increased with increased duration of coma. Of the patients who were in coma for more than 7 days, none regained consciousness. It should be noted that 80 patients died in a coma.
| | ==Treatment== |
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| ==Systematic Efforts to Improve Survival Following Cardiac Arrest: The Chain of Survival==
| | [[Anoxic brain injury medical therapy|Medical Therapy]] | [[Anoxic brain injury surgery|Surgery]] | [[Anoxic brain injury cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Anoxic brain injury future or investigational therapies|Future or Investigational Therapies]] |
| Multiple organizations now promote the "Chain of Survival" as a way to maximise prognosis following cardiac arrest. The Chain of Survival is made up of 4 links:
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| * '''Early Access''' - Early identification of patients at risk of cardiac arrest early is an effective way of improving prognosis, as it is often possible to prevent the cardiac arrest. Similarly, if the arrest is witnessed there is a much greater chance of survival, as treatment can be innitiated immediately.
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| * '''Early [[CPR]]''' - Cardiopulmonary resuscitation (CPR) buys time by maintaining a limited circulation until it is possible to defibrillate the patient. Effective CPR may minimize the risk of cerebral hypoxia (which can lead to neurological impairment following restoration of circulation).
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| * '''Early [[defibrillation]]''' - The earlier defibrillation of VT/VF is performed, the better the prognosis. Untreated VF/VT often degenerates into asystole which is poorly responsive to defibrillation.
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| * '''Early [[hospital]] care''' - Many patients suffer recurrent cardiac arrest within the first 24 hours of admission, and outcomes are improved with inpatient care in a monitored setting that allows early defibrillation.
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| ==References== | | ==Case Studies== |
| {{reflist|2}} | | [[Anoxic brain injury case study one|Case #1]] |
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| | ==Related Chapters== |
| | *[[Sudden cardiac death]] |
| | *[[Therapeutic hypothermia]] |
| | *[[Post cardiac arrest syndrome care pathway]] |
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| | {{WH}} |
| | {{WS}} |
| | [[CME Category::Cardiology]] |
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| [[Category:Cardiology]] | | [[Category:Cardiology]] |
| [[Category:Neurology]] | | [[Category:Neurology]] |
| [[Category:Emergency medicine]] | | [[Category:Emergency medicine]] |
| | | [[Category:Up-To-Date]] |
| {{WH}}
| | [[Category:Up-To-Date cardiology]] |
| {{WS}}
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