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112-425: In contrast to defibrillation, synchronized electrical cardioversion is an electrical shock delivered in synchrony to the cardiac cycle . Although the person may still be critically ill , cardioversion normally aims to end poorly perfusing cardiac arrhythmias , such as supraventricular tachycardia . Defibrillators can be external, transvenous, or implanted ( implantable cardioverter-defibrillator ), depending on

224-465: A thoracotomy and possess pacing , cardioversion, and defibrillation capabilities. The invention of implantable units is invaluable to some people with regular heart problems, although they are generally only given to those people who have already had a cardiac episode. People can live long normal lives with the devices. Many patients have multiple implants. A patient in Houston, Texas had an implant at

336-485: A bystander, early use of a defibrillator, and early advanced life support once more qualified medical help arrives. Qualified bystanders with training in BLS are encouraged to perform the first three steps of the five-link chain of survival. High Quality CPR High quality cardiopulmonary resuscitation (CPR) and early defibrillation using an automated external defibrillator (AED) are the most important aspects of BLS to ensure

448-419: A device to externally jump start the heart. He invented the defibrillator and tested it on a dog, like Prévost and Batelli. The first use on a human was in 1947 by Claude Beck , professor of surgery at Case Western Reserve University . Beck's theory was that ventricular fibrillation often occurred in hearts that were fundamentally healthy, in his terms "Hearts that are too good to die", and that there must be

560-506: A federal program in the National Institute of Health in physiology and medicine, telling Congress: "Let's compete with U.S.S.R. in research on reversibility of death". In 1959 Bernard Lown commenced research in his animal laboratory in collaboration with engineer Barouh Berkovits into a technique which involved charging of a bank of capacitors to approximately 1000 volts with an energy content of 100–200 joules then delivering

672-606: A heart attack and, purely by chance, the ambulance that responded to the call carried a defibrillator. After recovering, Kerry Packer donated a large sum to the Ambulance Service of New South Wales in order that all ambulances in New South Wales should be fitted with a personal defibrillator, which is why defibrillators in Australia are sometimes colloquially called "Packer Whackers". Cardioversion Cardioversion

784-414: A mainly uniphasic characteristic. Biphasic defibrillation alternates the direction of the pulses, completing one cycle in approximately 12 milliseconds. Biphasic defibrillation was originally developed and used for implantable cardioverter-defibrillators. When applied to external defibrillators, biphasic defibrillation significantly decreases the energy level necessary for successful defibrillation, decreasing

896-432: A manual defibrillator when appropriate. An internal defibrillator is often used to defibrillate the heart during or after cardiac surgery such as a heart bypass . The electrodes consist of round metal plates that come in direct contact with the myocardium. Manual internal defibrillators deliver the shock through paddles placed directly on the heart. They are mostly used in the operating room and, in rare circumstances, in

1008-471: A patient is coughing forcefully, rescuers should not interfere with this process and encourage the patient to keep coughing. If a patient shows signs of severe airway obstruction, anti-choking maneuvers such as back slaps or in the most severe cases abdominal thrusts should be applied until the obstruction is relieved. If a patient becomes unresponsive he should be lowered to the ground, and the rescuer should call emergency medical services and initiate CPR. When

1120-608: A patient survives. CPR involves a rescuer or bystander providing chest compressions to a patient in a supine position while also giving rescue breaths. The rescuer or bystander can also choose not to provide breaths and provide compression-only CPR. Depending on the age and circumstances of the patient, there can be variations in the compression to breath ratio given. European Resuscitation Council According to 2015 guidelines published by European resuscitation council , early initiation of resuscitation and coordination of lay people with medical personnel on helping an unconscious person

1232-411: A perfusing cardiac rhythm. These early defibrillators used the alternating current from a power socket, transformed from the 110–240 volts available in the line, up to between 300 and 1000 volts, to the exposed heart by way of "paddle" type electrodes. The technique was often ineffective in reverting VF while morphological studies showed damage to the cells of the heart muscle post-mortem. The nature of

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1344-459: A plausible and practical application." The problems to be overcome were the design of a system which would allow detection of ventricular fibrillation or ventricular tachycardia. Despite the lack of financial backing and grants, they persisted and the first device was implanted in February 1980 at Johns Hopkins Hospital by Dr. Levi Watkins Jr. assisted by Vivien Thomas . Modern ICDs do not require

1456-529: A presentation of shock at the Compensated , Decompensated, and Irreversible Stage. In cases of drowning, rescuers should provide CPR as soon as an unresponsive patient is removed from the water. In particular, rescue breathing is important in this situation. A lone rescuer is typically advised to give CPR for a short time before leaving the patient to call emergency medical services. Since the primary cause of cardiac arrest and death in drowning and choking patients

1568-415: A pulse is present (e.g., atrial flutter , atrial fibrillation ). However, if a patient is confirmed to be in pulseless ventricular tachycardia "v-tach" or ventricular fibrillation "v-fib", then a shock is delivered immediately upon connection of the pads. In this application, electrical cardioversion is more properly termed defibrillation . Once the machine is synced with the patient's cardiac rhythm,

1680-405: A pulse is present. Pulseless ventricular tachycardia and ventricular fibrillation are treated with unsynchronized shocks referred to as defibrillation . Electrical therapy is inappropriate for sinus tachycardia , which should always be a part of the differential diagnosis . Various antiarrhythmic agents can be used to return the heart to normal sinus rhythm . Pharmacological cardioversion

1792-411: A ring magnet to place over the device, which effectively disables the shock function of the device while still allowing the pacemaker to function (if the device is so equipped). If the device is shocking frequently, but appropriately, EMS personnel may administer sedation. A wearable cardioverter defibrillator is a portable external defibrillator that can be worn by at-risk patients. The unit monitors

1904-427: A shock at the appropriate time. The machine should synchronize ('sync') with the R wave of the rhythm strip. Although uncommon, sometimes the machine will unintentionally sync to high amplitude T waves, so it is important to ensure that the machine is synced appropriately to R waves. Interpretation of the patient's rhythm is imperative when using cardioversion to restore sinus rhythm from less emergent arrhythmias where

2016-400: A shock can be delivered to the patient. Following electrical cardioversion, the cardiologist will determine if sinus rhythm has been restored. To confirm sinus rhythm, a distinct P wave should be seen preceding each QRS complex. Additionally, each R-R interval should be evenly spaced. If sinus rhythm is restored, the pads may be disconnected, and any other medical equipment is removed from

2128-416: A shockable rhythm (such as VF or pulseless ventricular tachycardia) have improved survival rates, ranging between 21 and 50%. Manual external defibrillators require the expertise of a healthcare professional. They are used in conjunction with an electrocardiogram , which can be separate or built-in. A healthcare provider first diagnoses the cardiac rhythm and then manually determine the voltage and timing for

2240-428: A software modeling system capable of mapping an individual's chest and determining the best position for an external or internal cardiac defibrillator. Defibrillation halts chaotic cardiac activity by forcibly depolarizing heart cells, disrupting re-entrant circuits, and allowing for the heart's natural pacemaker to take over. Cardiac cells require a strong electrical stimulus to raise their transmembrane potential to

2352-491: A therapeutic dose of electric current to the heart at a random moment in the cardiac cycle , and is the most effective resuscitation measure for cardiac arrest associated with ventricular fibrillation and pulseless ventricular tachycardia . ) Pharmacologic cardioversion , also called chemical cardioversion , uses antiarrhythmia medication instead of an electrical shock. To perform synchronized electrical cardioversion, two electrode pads are used (or, alternatively,

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2464-482: A way of saving them. Beck first used the technique successfully on a 14-year-old boy who was having his breastbone separated from his ribs because of a congenital growth disorder, causing breathing problems. The boy's chest was surgically opened, and manual cardiac massage was undertaken for 45 minutes until the arrival of the defibrillator. Beck used internal paddles on either side of the heart, along with procainamide , an antiarrhythmic drug, and achieved return of

2576-424: Is a medical procedure by which an abnormally fast heart rate ( tachycardia ) or other cardiac arrhythmia is converted to a normal rhythm using electricity or drugs . Synchronized electrical cardioversion uses a therapeutic dose of electric current to the heart at a specific moment in the cardiac cycle , restoring the activity of the electrical conduction system of the heart . ( Defibrillation uses

2688-400: Is an especially good option in patients with atrial fibrillation of recent onset. Drugs that are effective at maintaining normal rhythm after electric cardioversion can also be used for pharmacological cardioversion. Drugs like amiodarone , diltiazem , verapamil and metoprolol are frequently given before electrical cardioversion to decrease the heart rate, stabilize the patient and increase

2800-402: Is attained. After the procedure, the patient is monitored to ensure stability of the sinus rhythm. Synchronized electrical cardioversion is used to treat hemodynamically unstable supraventricular (or narrow complex) tachycardias , including atrial fibrillation and atrial flutter . It is also used in the emergent treatment of wide complex tachycardias, including ventricular tachycardia , when

2912-402: Is essential during resuscitation. Defibrillation during the first 3 to 5 minutes during resuscitation can produce survival rates as high as 50 to 70%. Placing AEDs in public places where there is one cardiac arrest in five years is cost-effective. Although the adult CPR sequence can be safely used in children, a modified sequence of basic life support that entails less forceful chest compression

3024-599: Is even more suitable in children. United Kingdom Adult BLS guidelines in the United Kingdom were published in 2015 by the Resuscitation Council (UK), based on the 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations (CoSTR) published in November 2005. The newest guidelines for adult BLS allow a rescuer to diagnose cardiac arrest if

3136-425: Is hypoxemia, it is recommended to start with rescue breaths before proceeding to chest compressions (if pulseless). If the patient presents in a shockable rhythm, early defibrillation is still recommended. Choking occurs when a foreign body obstructs the trachea. Rescuers should only intervene in patients who show signs of severe airway obstruction, such as a silent cough, cyanosis, or inability to speak or breathe. If

3248-491: Is indicated only in certain types of cardiac dysrhythmias , specifically ventricular fibrillation (VF) and pulseless ventricular tachycardia . If the heart has completely stopped, as in asystole or pulseless electrical activity (PEA) , defibrillation is not indicated. Defibrillation is also not indicated if the patient is conscious or has a pulse. Improperly given electrical shocks can cause dangerous dysrhythmias, such as ventricular fibrillation. A defibrillation device that

3360-520: Is largely a scheduled procedure. In addition to cardiology, anesthesiology is also usually involved to ensure comfort of the patient for the duration of the shock therapy. The presence of registered nurses, physician associates, or other medical personnel may also be helpful during the procedure. Before starting the procedure, the patient's chest and back will be prepped for electrode placement. The skin should be free of any oily substances (e.g., lotions) and hair which may otherwise interfere with adhesion of

3472-464: Is likely to occur (but has not yet), self-adhesive pads may be placed prophylactically. Pads also offer an advantage to the untrained user, and to medics working in the sub-optimal conditions of the field. Pads do not require extra leads to be attached for monitoring, and they do not require any force to be applied as the shock is delivered. Thus, adhesive electrodes minimize the risk of the operator coming into physical (and thus electrical) contact with

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3584-400: Is not normal medical practice, as the heart cannot be restarted by the defibrillator itself. Only the cardiac arrest rhythms ventricular fibrillation and pulseless ventricular tachycardia are normally defibrillated. The purpose of defibrillation is to depolarize the entire heart all at once so that it is synchronized, effectively inducing temporary asystole, in the hope that in the absence of

3696-402: Is often available outside of medical centers is the automated external defibrillator (AED), a portable machine that can be used with no previous training. That is possible because the machine produces pre-recorded voice instructions that guide the user. The device automatically checks the patient's condition and applies the correct electric shocks. There also exist written instructions that explain

3808-488: Is required, the machine is charged, and the shock is delivered, without any need to apply any additional gel or to retrieve and place any paddles. Most adhesive electrodes are designed to be used not only for defibrillation, but also for transcutaneous pacing and synchronized electrical cardioversion . These adhesive pads are found on most automated and semi-automated units and are replacing paddles entirely in non-hospital settings. In hospital, for cases where cardiac arrest

3920-419: Is the availability of the automated external defibrillator or AED. This improves survival outcomes in cardiac arrest cases. One of the first checks done in emergency response is to assess the situation for any danger. If the person does not remove themselves or others from the danger then they are liable to become a patient and require emergency assistance themselves or become unable to render assistance for

4032-527: Is the basis for modern defibrillators. A major breakthrough was the introduction of portable defibrillators used out of the hospital. Already Peleška's Prema defibrillator was designed to be more portable than original Gurvich's model. In Soviet Union, a portable version of Gurvich's defibrillator, model ДПА-3 (DPA-3), was reported in 1959. In the west this was pioneered in the early 1960s by Prof. Frank Pantridge in Belfast . Today portable defibrillators are among

4144-475: Is the traditional metal "hard" paddle with an insulated (usually plastic) handle. This type must be held in place on the patient's skin with approximately 25 lbs (11.3 kg) of force while a shock or a series of shocks is delivered. Paddles offer a few advantages over self-adhesive pads. Many hospitals in the United States continue the use of paddles, with disposable gel pads attached in most cases, due to

4256-475: Is trained for providing BLS and/or ACLS . The International Liaison Committee on Resuscitation (ILCOR) was formed in 1992 to coordinate the efforts of resuscitation worldwide. The ILCOR representatives come from various countries such as the United States, Canada, Australia, New Zealand, and from the European, Asian, and African continents. In 2000, the committee published the first resuscitation guideline. In 2005,

4368-448: Is very helpful in increasing the chance of survival of the patient. When a person is unconscious and is not breathing normally, emergency services should be alerted and cardiopulmonary resuscitation (CPR) and mouth-to-mouth resuscitation (rescue breaths) should be initiated. High quality CPR is important. An adequate ratio of high quality chest compressions and rescue breaths are crucial. An automated external defibrillator (AED) machine

4480-441: The 3 parts of the cardiovascular system for metabolism to be processed effectively. However, if one part were to fail, important resources for cellular respiration such as oxygen would not be able to reach the organs that needs it function. In an attempt to compensate, the body diverts blood to organs that cannot tolerate the lack of blood, such as the heart and the brain, resulting in widespread vasoconstriction , or thinning of

4592-491: The AC machine with a large transformer also made these units very hard to transport, and they tended to be large units on wheels. Until the early 1950s, defibrillation of the heart was possible only when the chest cavity was open during surgery. The technique used an alternating voltage from a 300 or greater volt source derived from standard AC power, delivered to the sides of the exposed heart by "paddle" electrodes where each electrode

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4704-578: The American Heart Association, in order to be certified in BLS, a student must take an online or in-person course. However, an online BLS course must be followed with an in-person skills session in order to obtain a certification issued by The American Heart Association. Chain of survival The American Heart Association highlights the most important steps of BLS in a "five-link chain of survival." The chain of survival includes early recognition of an ongoing emergency, early initiation of CPR by

4816-557: The Beth Davis Hospital of New York City and C. Henry Hyman, an electrical engineer, looking for an alternative to injecting powerful drugs directly into the heart, came up with an invention that used an electrical shock in place of drug injection. This invention was called the Hyman Otor where a hollow needle is used to pass an insulated wire to the heart area to deliver the electrical shock. The hollow steel needle acted as one end of

4928-470: The DC discharge) which would burn the patient. Gel may be either wet (similar in consistency to surgical lubricant ) or solid (similar to gummi candy ). Solid-gel is more convenient, because there is no need to clean the used gel off the person's skin after defibrillation. However, the use of solid-gel presents a higher risk of burns during defibrillation, since wet-gel electrodes more evenly conduct electricity into

5040-706: The United States are generally identified with Emergency Medical Technicians-Basic (EMT-B). EMT-B is the highest level of healthcare provider that is limited to the BLS protocol; higher medical functions use some or all of the Advanced Cardiac Life Support (ACLS) protocols, in addition to BLS protocols. However, the American Heart Association 's BLS protocol is designed for use by laypeople, as well as students and others certified first responder , and to some extent, higher medical function personnel. BLS for Healthcare Providers Course According to

5152-492: The action potential of the SA and AV nodes. If the patient is stable, adenosine may be used for restoration of sinus rhythm in patients with macro-reentrant supraventricular tachycardias. It causes a short-lived cessation of conduction through the atrio-ventricular node breaking the circus movement through the node and the macro-reentrant pathway restoring sinus rhythm. Cardioversion for restoration of sinus rhythm from an atrial rhythm

5264-541: The activation threshold. Only a small amount of electrical current enters the cell due to high membrane impedance.The intracellular voltage of the cell remains uniform, while the extracellular voltage rapidly increases or decreases depending on proximity to the electrodes.This creates a voltage gradient that alters the transmembrane potential of cells, potentially resetting irregular electrical activity to restore normal cardiac rhythm. Irregular rhythms often result from re-entrant circuits, where electrical impulses circle within

5376-418: The age of 18 in 1994 by the recent Dr. Antonio Pacifico. He was awarded "Youngest Patient with Defibrillator" in 1996. Today these devices are implanted into small babies shortly after birth. As devices that can quickly produce dramatic improvements in patient health, defibrillators are often depicted in movies, television, video games and other fictional media. Their function, however, is often exaggerated with

5488-399: The age of 8 or those under 55 lbs. (22 kg). Resuscitation electrodes are placed according to one of two schemes. The anterior-posterior scheme is the preferred scheme for long-term electrode placement. One electrode is placed over the left precordium (the lower part of the chest, in front of the heart). The other electrode is placed on the back, behind the heart in the region between

5600-407: The airway is opened during CPR, the rescuer should look into the mouth for an object causing obstruction, and remove with a finger sweep it if it is evident however many organisations state that the rescuer should not try to remove the foreign object as they might worsen the situation (either pushing it further down the trachea or initiating vomiting). Basic Life Support Emergency Medical Services in

5712-408: The airway via the jaw-thrust maneuver is the preferred method as the head-tilt maneuver is thought to be more risky for people with suspected spinal injury or inconveniency. If the person is in danger of pulmonary aspiration then they should be placed in the recovery position or more advanced airway management should be used. Once the airway has been opened checking for breathing should begin, if

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5824-429: The algorithm for basic life support (BLS). Many first responders , such as firefighters, police officers, and security guards, are equipped with them. AEDs can be fully automatic or semi-automatic. A semi-automatic AED automatically diagnoses heart rhythms and determines if a shock is necessary. If a shock is advised, the user must then push a button to administer the shock. A fully automated AED automatically diagnoses

5936-430: The availability of Automated External Defibrillators. These devices can analyse the heart rhythm by themselves, diagnose the shockable rhythms, and charge to treat. This means that no clinical skill is required in their use, allowing lay people to respond to emergencies effectively. Until the mid 1990s, external defibrillators delivered a Lown type waveform (see Bernard Lown ), a heavily damped sinusoidal impulse having

6048-408: The benefits against adverse effects including apnea. Bite blocks and extremity restraints are then utilized to prevent self-injury during cardioversion. Once these medications are administered, the glabellar reflex or eyelash reflex may be used to determine the patient's level of consciousness. The pads are connected to a machine that can interpret the patient's cardiac rate and rhythm and deliver

6160-619: The beta-1 receptor are called cardio selective because beta-1 is responsible for increasing heart rate; hence a beta blocker will slow the heart rate. Class III agents (prolong repolarization by blocking outward K+ current): amiodarone and sotalol are effective class III agents. Ibutilide is another Class III agent but has a different mechanism of action (acts to promote influx of sodium through slow-sodium channels). It has been shown to be effective in acute cardioversion of recent-onset atrial fibrillation and atrial flutter. Class IV drugs are calcium (Ca) channel blockers. They work by inhibiting

6272-404: The blood flowing by performing chest compressions and rescue breaths at an age-appropriate rate until it is. Respiratory arrest is when there is no measurable breathing in a patient. It tends to occur in conjunction with cardiac arrest, but this is not always the case. Respiratory arrest is the most common indication of BLS in infants and toddlers. The most critical factor in restoring breathing in

6384-506: The blood vessels. Consequently, blood is prevented from reaching organs that can tolerate the lack of perfusion, or hypoperfusion, in organs such as the skin, resulting in the typical presentation of pale and clammy skin conditions during shock . Moreover, disruptions may present specifically to each component or multiple systems may be affected at the same time, which generally results in the 3 designated types of shock: Obstructive , Distributive , Hypovolemic . Typically, patients would have

6496-603: The body. Paddle electrodes, which were the first type developed, come without gel, and must have the gel applied in a separate step. Self-adhesive electrodes come prefitted with gel. There is a general division of opinion over which type of electrode is superior in hospital settings; the American Heart Association favors neither, and all modern manual defibrillators used in hospitals allow for swift switching between self-adhesive pads and traditional paddles. Each type of electrode has its merits and demerits. The most well-known type of electrode (widely depicted in films and television)

6608-558: The cardioverter to deliver a reversion shock, by way of the pads, of a selected amount of electric current over a predefined number of milliseconds at the optimal moment in the cardiac cycle which corresponds to the R wave of the QRS complex on the ECG . Timing the shock to the R wave prevents the delivery of the shock during the vulnerable period (or relative refractory period) of the cardiac cycle , which could induce ventricular fibrillation . If

6720-471: The chance of survival. It is also acknowledged that rescuers may either be unable, or unwilling, to give effective rescue breaths; in this situation, continuing chest compressions alone is advised, although this is only effective for about 5 minutes. For choking, the guidelines in the United Kingdom first call for assessing the severity of the situation. If the patient is able to speak and cough effectively,

6832-654: The chance that cardioversion is successful. There are various classes of agents that are most effective for pharmacological cardioversion. Class I agents are sodium (Na) channel blockers (which slow conduction by blocking the Na+ channel) and are divided into 3 subclasses a, b and c. Class Ia slows phase 0 depolarization in the ventricles and increases the absolute refractory period. Procainamide , quinidine and disopyramide are Class Ia agents. Class 1b drugs lengthen phase 3 repolarization. They include lidocaine , mexiletine and phenytoin . Class Ic greatly slow phase 0 depolarization in

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6944-417: The charge through an inductance such as to produce a heavily damped sinusoidal wave of finite duration (~5 milliseconds ) to the heart by way of paddle electrodes. This team further developed an understanding of the optimal timing of shock delivery in the cardiac cycle, enabling the application of the device to arrhythmias such as atrial fibrillation , atrial flutter , and supraventricular tachycardias in

7056-432: The circuit and the tip of the insulated wire the other end. Whether the Hyman Otor was a success is unknown. The external defibrillator, as it is known today, was invented by electrical engineer William Kouwenhoven in 1930. Kouwenhoven studied the relationship between electric shocks and their effects on the human heart when he was a student at Johns Hopkins University School of Engineering. His studies helped him invent

7168-484: The committee published International Consensus on Cardiopulmonary resuscitation (CPR) and Emergency Cardiovascular Care (ECC) Science with Treatment Recommendations. Since 2010, the committee has provided materials for regional resuscitation providers such as European Resuscitation Council and American Heart Association to write their own guidelines. Since 2015, ILCOR has used a new methodology called Consensus on Science with Treatment Recommendations (COSTR) to evaluate

7280-414: The defibrillator inducing a sudden, violent jerk or convulsion by the patient. The pad placement is also shown wrong, along with sudden rising of patient to large height when shock is given. In reality, while the muscles may contract, such dramatic patient presentation is rare. Similarly, medical providers are often depicted defibrillating patients with a "flat-line" ECG rhythm (also known as asystole ). This

7392-462: The electrical shock. These units are primarily found in hospitals and on some ambulances . For instance, every NHS ambulance in the United Kingdom is equipped with a manual defibrillator for use by the attending paramedics and technicians. In the United States , many advanced EMTs and all paramedics are trained to recognize lethal arrhythmias and deliver appropriate electrical therapy with

7504-681: The emergency room during an open heart procedure . Automated external defibrillators (AEDs) are designed for use by untrained or briefly trained laypersons. AEDs contain technology for analysis of heart rhythms. As a result, it does not require a trained health provider to determine whether or not a rhythm is shockable. By making these units publicly available, AEDs have improved outcomes for sudden out-of-hospital cardiac arrests. Trained health professionals have more limited use for AEDs than manual external defibrillators. Recent studies show that AEDs does not improve outcome in patients with in-hospital cardiac arrests. AEDs have set voltages and does not allow

7616-408: The heart rhythm and advises the user to stand back while the shock is automatically given. Some types of AEDs come with advanced features, such as a manual override or an ECG display. Implantable cardioverter-defibrillators , also known as automatic internal cardiac defibrillator (AICD), are implants similar to pacemakers (and many can also perform the pacemaking function). They constantly monitor

7728-446: The heart tissue due to areas of slow conduction or unidirectional block. The widespread depolarization from the shock interrupts these circuits, stopping the erratic propagation of electrical signals. After the cells depolarize, they enter a refractory period, during which they cannot be re-excited.This allows the heart's natural pacemaker, the sinoatrial node, to resume control of the rhythm. During this period, ion pumps actively restore

7840-442: The heart to stop heart fibrillation . In 1972, Lown stated in the journal Circulation – "The very rare patient who has frequent bouts of ventricular fibrillation is best treated in a coronary care unit and is better served by an effective antiarrhythmic program or surgical correction of inadequate coronary blood flow or ventricular malfunction. In fact, the implanted defibrillator system represents an imperfect solution in search of

7952-475: The inherent speed with which these electrodes can be placed and used. This is critical during cardiac arrest, as each second of nonperfusion means tissue loss. Modern paddles allow for monitoring ( electrocardiography ), though in hospital situations, separate monitoring leads are often already in place. Paddles are reusable, being cleaned after use and stored for the next patient. Gel is therefore not preapplied, and must be added before these paddles are used on

8064-453: The level of consciousness in a patient. Pain stimulus in particular should be used with caution as many methods if done incorrectly can leave bruises (sternal rub for example) commonly used methods for central stimulus are the trapezius squeeze and for peripheral stimulus it is squeezing the side of the finger. Sending for help allows much more assistance to be rendered upon the patient and increases their chances of receiving ALS. Opening of

8176-495: The life-threatening arrhythmia is ventricular fibrillation, the device is programmed to proceed immediately to an unsynchronized shock. There are cases where the patient's ICD may fire constantly or inappropriately. This is considered a medical emergency , as it depletes the device's battery life, causes significant discomfort and anxiety to the patient, and in some cases may actually trigger life-threatening arrhythmias. Some emergency medical services personnel are now equipped with

8288-413: The machine must be charged. To determine the amount of energy (measured in joules "J") the patient requires, many factors are considered. As a rule of thumb, recent-onset atrial arrhythmias require less energy compared to persistent atrial arrhythmias. If the cardiologist suspects that the patient may be less respondent to cardioversion, a higher energy may be utilized. Once the machine is synced and charged,

8400-444: The many very important tools carried by ambulances. They are the only proven way to resuscitate a person who has had a cardiac arrest unwitnessed by Emergency Medical Services (EMS) who is still in persistent ventricular fibrillation or ventricular tachycardia at the arrival of pre-hospital providers. Gradual improvements in the design of defibrillators, partly based on the work developing implanted versions (see below), have led to

8512-457: The midaxillary line. Basic life support 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 (paramedics, nurses, physicians or any trained general personnel). It can be provided by trained medical personnel, such as emergency medical technicians , qualified bystanders and anybody who

8624-487: The normal distribution of ions, re-establishing the resting membrane potential. Defibrillators were first demonstrated in 1899 by Jean-Louis Prévost and Frédéric Batelli, two physiologists from the University of Geneva , Switzerland. They discovered that small electrical shocks could induce ventricular fibrillation in dogs, and that larger charges would reverse the condition. In 1933, Dr. Albert Hyman, heart specialist at

8736-808: The obstruction is mild. If the patient is unable to speak or cough effectively, or is unable to breathe or is breathing with a wheezy sound, the airway obstruction is severe. It is then recommended to perform back blows until the obstruction clears. If the patient becomes unresponsive, CPR is started. The term BLS is also used in some non-English speaking countries (e.g. in Italy ) for the education of first responders . Terms with similar meanings for similar skill sets are also common. When performing BLS, laypeople and medical personnel are encouraged to remember that some groups of people have certain conditions that need to be taken into considerations. To relieve choking, chest thrusts should be used instead of abdominal thrusts when

8848-628: The operator to vary voltage according to need. AEDs may also delay delivery of effective CPR. For diagnosis of rhythm, AEDs often require the stopping of chest compressions and rescue breathing. For these reasons, certain bodies, such as the European Resuscitation Council, recommend using manual external defibrillators over AEDs if manual external defibrillators are readily available. As early defibrillation can significantly improve VF outcomes, AEDs have become publicly available in many easily accessible areas. AEDs have been incorporated into

8960-424: The other patient. Examples of dangerous situations which should cease before BLS is administered are electrocution, assault, drowning, burning etc. Checking for response is the next step in emergency situations as continuing with other forceful methods of BLS could exacerbate the patient's condition and can be seen as assault. AVPU (Alert, Verbal, Pain, Unconscious) is the commonly used acronym for quickly assessing

9072-443: The pads. Once this is complete, the medical team will adhere the pads to the patient using a rolling motion to ensure the absence of air pockets. (see details on pad placement below) . The anesthesiology team will then administer a general anesthetic (e.g., Propofol ) in order to ensure patient comfort and amnesia during the procedure. Opioid analgesics (e.g., Fentanyl) may be combined with Propofol, although anesthesiology must weight

9184-442: The patient 24 hours a day and can automatically deliver a biphasic shock if VF or VT is detected. This device is mainly indicated in patients who are not immediate candidates for ICDs. The connection between the defibrillator and the patient consists of a pair of electrodes, each provided with electrically conductive gel in order to ensure a good connection and to minimize electrical resistance , also called chest impedance (despite

9296-448: The patient and/or provider. Pad placement for electrical cardioversion a cardiac arrhythmia may be either anterior-posterior or anterior-lateral. In an anterior-posterior setup one pad is placed on the chest and the other pad is placed on the back. In an anterior-lateral setup, one pad is placed on the chest and the other pad is placed along the left midaxillary line. Choosing the right pad placement can be an important aspect when measuring

9408-445: The patient as the shock is delivered by allowing the operator to be up to several feet away. (The risk of electrical shock to others remains unchanged, as does that of shock due to operator misuse.) Self-adhesive electrodes are single-use only. They may be used for multiple shocks in a single course of treatment, but are replaced if (or in case) the patient recovers then reenters cardiac arrest. Special pads are used for children under

9520-422: The patient is conscious, various drugs are often used to help sedate the patient and make the procedure more tolerable. However, if the patient is hemodynamically unstable or unconscious, the shock is given immediately upon confirmation of the arrhythmia . When synchronized electrical cardioversion is performed as an elective procedure, the shocks can be performed in conjunction with drug therapy until sinus rhythm

9632-404: The patient is not in cardiac arrest, such as supraventricular tachycardia and ventricular tachycardia that produces a pulse ; this more-complicated procedure is known as cardioversion , not defibrillation. In Australia up until the 1990s it was relatively rare for ambulances to carry defibrillators. This changed in 1990 after Australian media mogul Kerry Packer had a cardiac arrest due to

9744-477: The patient is to provide high quality rescue breaths. Shock , also known as Inadequate Tissue Perfusion, is a life-threatening condition that occurs as a result of the disruption to 3 major components of the cardiovascular system : Heart Function, Blood Vessel Function, and Blood Volume. Perfusion describes the process of adequate blood flow to the organs, where the waste and reactants that are involved in cellular respiration are removed or transported throughout

9856-424: The patient is unresponsive and not breathing normally. The guidelines also changed the duration of rescue breaths and the placement of the hand on the chest when performing chest compressions. These changes were introduced to simplify the algorithm , to allow for faster decision making and to maximize the time spent giving chest compressions; this is because interruptions in chest compressions have been shown to reduce

9968-431: The patient's back. The anterior pad should be placed inferior to the right clavicle while also being vertically centered over at the level of the right 4th intercostal space. The posterior pad should be placed just lateral to the left side of the spine and vertically centered at the level of T7. The inferior angle of the scapula can be used as a reference for the level of T7. The anterior pad should be placed inferior to

10080-418: The patient's heart rhythm, and automatically administer shocks for various life-threatening arrhythmias, according to the device's programming. Many modern devices can distinguish between ventricular fibrillation , ventricular tachycardia , and more benign arrhythmias like supraventricular tachycardia and atrial fibrillation . Some devices may attempt overdrive pacing prior to synchronised cardioversion. When

10192-419: The patient. Paddles are generally only found on manual external units. Newer types of resuscitation electrodes are designed as an adhesive pad, which includes either solid or wet gel. These are peeled off their backing and applied to the patient's chest when deemed necessary, much the same as any other sticker. The electrodes are then connected to a defibrillator, much as the paddles would be. If defibrillation

10304-442: The patients (e.g., bite blocks, restraints, etc.). The patient will regain consciousness soon thereafter (the effects of Propofol generally last for only 3–8 minutes). However, if the arrhythmia is persistent, the machine may be re-charged to a higher energy level, and the cardioversion attempt may be repeated. It is recommended to wait 60 seconds between subsequent cardioversion attempts, but this amount of time may be adjusted based on

10416-469: The previous abnormal electrical activity, the heart will spontaneously resume beating normally. Someone who is already in asystole cannot be helped by electrical means, and usually needs urgent CPR and intravenous medication (and even these are rarely successful in cases of asystole). A useful analogy to remember is to think of defibrillators as power-cycling, rather than jump-starting, the heart. There are also several heart rhythms that can be "shocked" when

10528-470: The procedure step-by-step. Survival rates for out-of-hospital cardiac arrests in North America are poor, often less than 10%. Outcome for in-hospital cardiac arrests are higher at 20%. Within the group of people presenting with cardiac arrest, the specific cardiac rhythm can significantly impact survival rates. Compared to people presenting with a non-shockable rhythm (such as asystole or PEA), people with

10640-529: The quality of latest evidence available and to reach a conclusion on the best treatments available in resuscitation. Using the COSTR methodology, ILCOR also started to conduct yearly reviews and published updates on the latest evidence in resuscitation, changing it from the previous 5-yearly review on resuscitation. CPR provided in the field increases the time available for higher medical responders to arrive and provide ALS care. An important advance in providing BLS

10752-409: The rescuer of any impediments to continued CPR (such as a sinus rhythm or asystole ) in which case the rescuer may be prompted to cease CPR. Cardiac arrest occurs when the heart stops pumping in a regular rhythm. In this situation, early defibrillation is the key to returning the patient's heart back to a normal rhythm. When a defibrillator is not readily available, a rescuer or bystander should keep

10864-454: The respiratory rate is below 12-20 breaths per minute then CPR should begin, however if the patient is breathing normally then the rescuer should place them in the recovery position and summon an ambulance. Once an automated external defibrillator (AED) has been acquired the rescuer should then finish the round of CPR, use the AED and then begin another round of CPR. However the AED will usually notify

10976-444: The right clavicle while also being vertically centered over at the level of the right 4th intercostal space. The lateral pad should be placed along the left midaxillary line at the level of the left 5th intercostal space. The left nipple can be used as a reference for the level of the left 4th intercostal space. From here, the midaxillary 5th intercostal space is identified by moving inferiorly one intercostal space and laterally towards

11088-449: The risk of burns and myocardial damage. Ventricular fibrillation (VF) could be returned to sinus rhythm in 60% of cardiac arrest patients treated with a single shock from a monophasic defibrillator. Most biphasic defibrillators have a first shock success rate of greater than 90%. A further development in defibrillation came with the invention of the implantable device, known as an implantable cardioverter-defibrillator (or ICD). This

11200-537: The scapula. This placement is preferred because it is best for non-invasive pacing. The anterior-apex scheme (anterior-lateral position) can be used when the anterior-posterior scheme is inconvenient or unnecessary. In this scheme, the anterior electrode is placed on the right, below the clavicle. The apex electrode is applied to the left side of the patient, just below and to the left of the pectoral muscle. This scheme works well for defibrillation and cardioversion, as well as for monitoring an ECG. Researchers have created

11312-420: The shock time, then continues to decay for some time after which the voltage is cut off, or truncated. The studies showed that the biphasic truncated waveform could be more efficacious while requiring the delivery of lower levels of energy to produce defibrillation. An added benefit was a significant reduction in weight of the machine. The BTE waveform, combined with automatic measurement of transthoracic impedance,

11424-430: The success of electrical cardioversion. For example, the anterior-posterior pad positioning is commonly used when attempting to restore an atrial arrhythmia as the vector between the pads predominately runs through the atria. The anterior-lateral pad positioning may be used when attempting to restore pulseless ventricular tachycardia or ventricular fibrillation as there may not be enough time or strength to apply an electrode

11536-467: The technique known as " cardioversion ". The Lown-Berkovits waveform, as it was known, was the standard for defibrillation until the late 1980s. Earlier in the 1980s, the "MU lab" at the University of Missouri had pioneered numerous studies introducing a new waveform called a biphasic truncated waveform (BTE). In this waveform an exponentially decaying DC voltage is reversed in polarity about halfway through

11648-448: The traditional hand-held "paddles"), each comprising a metallic plate which is faced with a saline based conductive gel. The pads are placed on the chest of the patient, or one is placed on the chest and one on the back. These are connected by cables to a machine which has the combined functions of an ECG display screen and the electrical function of a defibrillator . A synchronizing function (either manually operated or automatic) allows

11760-446: The type of device used or needed. Some external units, known as automated external defibrillators (AEDs), automate the diagnosis of treatable rhythms, meaning that lay responders or bystanders are able to use them successfully with little or no training. Defibrillation is often an important step in cardiopulmonary resuscitation (CPR). CPR is an algorithm-based intervention aimed to restore cardiac and pulmonary function. Defibrillation

11872-509: The ventricles (however unlike 1a have no effect on the refractory period). Flecainide , moricizine and propafenone are Class Ic agents. Class II agents are beta blockers which inhibit SA and AV node depolarization and slow heart rate. They also decrease cardiac oxygen demand and can prevent cardiac remodeling. Not all beta blockers are the same; some are cardio selective (affecting only beta 1 receptors) while others are non-selective (affecting beta 1 and 2 receptors). Beta blockers that target

11984-472: Was a flat or slightly concave metal plate of about 40 mm diameter. The closed-chest defibrillator device which applied an alternating voltage of greater than 1000 volts, conducted by means of externally applied electrodes through the chest cage to the heart, was pioneered by Dr V. Eskin with assistance by A. Klimov in Frunze, USSR (today known as Bishkek , Kyrgyzstan ) in the mid-1950s. The duration of AC shocks

12096-460: Was awarded Grand Prix at Expo 58 . In 1958, US senator Hubert H. Humphrey visited Nikita Khrushchev and among other things he visited the Moscow Institute of Reanimatology, where, among others, he met with Gurvich. Humphrey immediately recognized importance of reanimation research and after that a number of American doctors visited Gurvich. At the same time, Humphrey worked on establishing

12208-417: Was carried out by Schuder and colleagues at the University of Missouri . The work was commenced, despite doubts amongst leading experts in the field of arrhythmias and sudden death. There was doubt that their ideas would ever become a clinical reality. In 1962 Bernard Lown introduced the external DC defibrillator. This device applied a direct current from a discharging capacitor through the chest wall into

12320-527: Was designated model ИД-1-ВЭИ ( Импульсный Дефибриллятор 1, Всесоюзный Электротехнический Институт , or in English, Pulse Defibrillator 1, All-Union Electrotechnical Institute ). It is described in detail in Gurvich's 1957 book, Heart Fibrillation and Defibrillation . The first Czechoslovak "universal defibrillator Prema" was manufactured in 1957 by the company Prema, designed by Dr. Bohumil Peleška. In 1958 his device

12432-478: Was pioneered at Sinai Hospital in Baltimore by a team that included Stephen Heilman, Alois Langer, Jack Lattuca, Morton Mower , Michel Mirowski , and Mir Imran , with the help of industrial collaborator Intec Systems of Pittsburgh. Mirowski teamed up with Mower and Staewen, and together they commenced their research in 1969. However, it was 11 years before they treated their first patient. Similar developmental work

12544-406: Was typically in the range of 100–150 milliseconds. Early successful experiments of successful defibrillation by the discharge of a capacitor performed on animals were reported by N. L. Gurvich and G. S. Yunyev in 1939. In 1947 their works were reported in western medical journals. Serial production of Gurvich's pulse defibrillator started in 1952 at the electromechanical plant of the institute, and

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