Cardiac arrest,also known as sudden cardiac arrest (SCA),is when the heart suddenly and unexpectedly stops beating. When the heart stops beating,blood cannot properly circulate around the body and the blood flow to the brain and other organs is decreased. When the brain does not receive enough blood,this can cause a person to lose consciousness and brain cells can start to die due to lack of oxygen. Coma and persistent vegetative state may result from cardiac arrest. Cardiac arrest is also identified by a lack of central pulses and abnormal or absent breathing.
Cardiopulmonary resuscitation (CPR) is an emergency procedure consisting of chest compressions often combined with artificial ventilation,or mouth to mouth in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person who is in cardiac arrest. It is recommended for those who are unresponsive with no breathing or abnormal breathing,for example,agonal respirations.
Clinical death is the medical term for cessation of blood circulation and breathing,the two criteria necessary to sustain the lives of human beings and of many other organisms. It occurs when the heart stops beating in a regular rhythm,a condition called cardiac arrest. The term is also sometimes used in resuscitation research.
Advanced cardiac life support,advanced cardiovascular life support (ACLS) refers to a set of clinical guidelines established by the American Heart Association (AHA) for the urgent and emergent treatment of life-threatening cardiovascular conditions that will cause or have caused cardiac arrest,using advanced medical procedures,medications,and techniques. ACLS expands on Basic Life Support (BLS) by adding recommendations on additional medication and advanced procedure use to the CPR guidelines that are fundamental and efficacious in BLS. ACLS is practiced by advanced medical providers including physicians,some nurses and paramedics;these providers are usually required to hold certifications in ACLS care.
A do-not-resuscitate order (DNR),also known as Do Not Attempt Resuscitation (DNAR),Do Not Attempt Cardiopulmonary Resuscitation (DNACPR),no code or allow natural death,is a medical order,written or oral depending on the jurisdiction,indicating that a person should not receive cardiopulmonary resuscitation (CPR) if that person's heart stops beating. Sometimes these decisions and the relevant documents also encompass decisions around other critical or life-prolonging medical interventions. The legal status and processes surrounding DNR orders vary in different polities. Most commonly,the order is placed by a physician based on a combination of medical judgement and patient involvement.
Asystole is the absence of ventricular contractions in the context of a lethal heart arrhythmia. Asystole is the most serious form of cardiac arrest and is usually irreversible. Also referred to as cardiac flatline,asystole is the state of total cessation of electrical activity from the heart,which means no tissue contraction from the heart muscle and therefore no blood flow to the rest of the body.
Basic life support (BLS) is a level of medical care which is used for patients with life-threatening condition of cardiac arrest until they can be given full medical care by advanced life support providers. It can be provided by trained medical personnel,such as emergency medical technicians,qualified bystanders and anybody who is trained for providing BLS and/or ACLS.
Precordial thump is a medical procedure used in the treatment of ventricular fibrillation or pulseless ventricular tachycardia under certain conditions. The procedure has a very low success rate,but may be used in those with witnessed,monitored onset of one of the "shockable" cardiac rhythms if a defibrillator is not immediately available. It should not delay cardiopulmonary resuscitation (CPR) and defibrillation,nor should it be used in those with unwitnessed out-of-hospital cardiac arrest.
Pulseless electrical activity (PEA) is a form of cardiac arrest in which the electrocardiogram shows a heart rhythm that should produce a pulse,but does not. Pulseless electrical activity is found initially in about 20% of out-of-hospital cardiac arrests and about 50% of in-hospital cardiac arrests.
The AutoPulse is an automated,portable,battery-powered cardiopulmonary resuscitation device created by Revivant and subsequently purchased and currently manufactured by ZOLL Medical Corporation. It is a chest compression device composed of a constricting band and half backboard that is intended to be used as an adjunct to CPR during advanced cardiac life support by professional health care providers. The AutoPulse uses a distributing band to deliver the chest compressions. In literature it is also known as LDB-CPR.
The chain of survival refers to a series of actions that,properly executed,reduce the mortality associated with sudden cardiac arrest. Like any chain,the chain of survival is only as strong as its weakest link. The six interdependent links in the chain of survival are early recognition of sudden cardiac arrest and access to emergency medical care,early CPR,early defibrillation,early advanced cardiac life support,and physical and emotional recovery. The first three links in the chain can be performed by lay bystanders,while the second three links are designated to medical professionals. Currently,between 70 and 90% of cardiac arrest patients die before they reach the hospital. However,a cardiac arrest does not have to be lethal if bystanders can take the right steps immediately.
Targeted temperature management (TTM) previously known as therapeutic hypothermia or protective hypothermia is an active treatment that tries to achieve and maintain a specific body temperature in a person for a specific duration of time in an effort to improve health outcomes during recovery after a period of stopped blood flow to the brain. This is done in an attempt to reduce the risk of tissue injury following lack of blood flow. Periods of poor blood flow may be due to cardiac arrest or the blockage of an artery by a clot as in the case of a stroke.
Return of spontaneous circulation (ROSC) is the resumption of a sustained heart rhythm that perfuses the body after cardiac arrest. It is commonly associated with significant respiratory effort. Signs of return of spontaneous circulation include breathing,coughing,or movement and a palpable pulse or a measurable blood pressure. Someone is considered to have sustained return of spontaneous circulation when circulation persists and cardiopulmonary resuscitation has ceased for at least 20 consecutive minutes.
An inspiratory impedance threshold device is a valve used in cardiopulmonary resuscitation (CPR) to decrease intrathoracic pressure and improve venous return to the heart. The valve is a part of a mask or other breathing device such as an endotracheal tube,and may open at high or low pressures
Extracorporeal cardiopulmonary resuscitation is a method of cardiopulmonary resuscitation (CPR) that passes the patient's blood through a machine in a process to oxygenate the blood supply. A portable extracorporeal membrane oxygenation (ECMO) device is used as an adjunct to standard CPR. A patient who is deemed to be in cardiac arrest refractory to CPR has percutaneous catheters inserted into the femoral vein and artery. Theoretically,the application of ECPR allows for the return of cerebral perfusion in a more sustainable manner than with external compressions alone. By attaching an ECMO device to a person who has acutely undergone cardiovascular collapse,practitioners can maintain end-organ perfusion whilst assessing the potential reversal of causal pathology,with the goal of improving long-term survival and neurological outcomes.
Lance B. Becker M.D. FAHA is an internationally recognized physician-scientist and a leading authority in the field of emergency medicine,resuscitation,cardiology,and critical care medicine. His work has revolutionized resuscitation science,particularly in the realms of cardiac arrest management,therapeutic hypothermia,therapies for reperfusion injury,and mitochondrial medicine.
Vinay M. Nadkarni is an American pediatric critical care physician. He is a Professor of Anesthesiology and Critical Care at the Hospital of the University of Pennsylvania and the Medical Director of the Center for Simulation,Advanced Education and Innovation at the Children's Hospital of Philadelphia (CHOP). Nadkarni also holds the institution’s Endowed Chair in Pediatric Critical Care Medicine and is a Fellow of the American College of Critical Care Medicine,the American Academy of Pediatrics,and the American Heart Association.
Brendan G. Carr,MD,MA,MS is an American physician and educator. He is Chief Executive Officer and Kenneth L. Davis,MD,Distinguished Chair of the Mount Sinai Health System as of 2024,and Professor and of Emergency Medicine at the Icahn School of Medicine at Mount Sinai and the Mount Sinai Health System.
The Lund University Cardiopulmonary Assist System (LUCAS) device provides mechanical chest compressions to patients in cardiac arrest. It is mostly used in emergency medicine as an alternative to manual CPR because it provides consistent compressions at a fixed rate through difficult transport conditions and eliminates the physical strain on the person performing CPR. The first generation of the LUCAS device was pneumatic,while the second and third generations are battery-operated.
Post-cardiac arrest syndrome (PCAS) is an inflammatory state of pathophysiology that can occur after a patient is resuscitated from a cardiac arrest. While in a state of cardiac arrest,the body experiences a unique state of global ischemia. This ischemia results in the accumulation of metabolic waste which instigate the production of inflammatory mediators. If return of spontaneous circulation (ROSC) is achieved after CPR,then circulation resumes,resulting in global reperfusion and the subsequent distribution of the ischemia products throughout the body. While PCAS has a unique cause and consequences,it can ultimately be thought of as type of global ischemia-reperfusion injury. The damage,and therefore prognosis,of PCAS generally depends on the length of the patient's ischemic period;therefore the severity of PCAS is not uniform across different patients.
