CPR for the Healthcare Provider

Transcription

1 presents CPR for the Healthcare Provider Copyright 2011 Fire & Emergency Training Network a division of All rights reserved.

2 Accreditation Information This continuing education activity is approved by FETN and PULSE Emergency Medical Update, an organization accredited by the Continuing Education Coordinating Board for Emergency Medical Services (CECBEMS) for 2 CEHs. This learning activity has been submitted for approval of continuing education hours to the Florida Department of Health, the Pennsylvania Department of Health, and the Commonwealth of Massachusetts Department of Public Health. For the most current credit approval information, visit our website at: criticalinfonet.com. For questions or general information, please contact: Customer Care 4101 International Pkwy Carrollton, TX

3 Subject Matter Expert Kenneth W. Navarro, MEd Assistant Professor, Emergency Medicine Education University of Texas Southwestern Medical Center Dallas, Texas Statement of need Cardiopulmonary resuscitation (CPR) is the only hope of survival for someone who suffers cardiac arrest. All healthcare providers should know how to properly perform CPR on both adult and pediatric patients following the latest guidelines from the American Heart Association (AHA). Learning Objectives After completing this activity, the participant should be able to: 1. Initiate the chain of survival. 2. Perform a high-quality CPR sequence, using the C-A-B model, on an adult patient. 3. List two impediments to performing high-quality CPR. 4. Demonstrate the steps in the proper use of an automated external defibrillator, or AED. 5. Perform a high-quality CPR sequence, using the C-A-B model, on a pediatric patient. DOT Standard EMT-Basic Medical INTRODUCTION Cardiovascular disease is a significant source of morbidity and mortality in the United States. Roughly 300,000 people suffer a cardiac arrest in the prehospital environment every year. EMS personnel attempt to resuscitate about 60 percent of those patients. Although the American Heart Association has continuously revised cardiac arrest treatment algorithms over the last 30 years, only about 8 percent of the patients who suffer an out-of-hospital cardiac arrest will survive long enough for discharge from a hospital. The foundation for all successful resuscitation attempts from sudden cardiac death is basic life support (BSL), which includes high-quality cardiopulmonary resuscitation (CPR). Unfortunately, bystanders or family members perform CPR on less than onethird of all cases. 3

4 Learning Objective: Initiate the Chain of Survival History of CPR In the 1950s, a team of researchers at Johns Hopkins University Medical Center were attempting to develop a method of external defibrillation when they observed that placing a heavy prototype defibrillation electrodes onto an experimental animal s chest wall produced a momentary rise in the intra-arterial pressure. Over the next few years, the research team methodically searched for the precise spot on the chest that produced maximum forward blood flow when compressed. In 1960, the team published the first paper on closed chest cardiac massage. One year later, Peter Safer combined artificial ventilation with the closed chest cardiac massage technique to create an early form of CPR. Adult Chain of Survival The American Heart Association s Emergency Cardiovascular Care (ECC) training programs emphasize a series of steps that rescuers must perform as quickly as possible. Linked together, these steps form a chain of survival that maximizes the potential for a successful resuscitation. With effective implementation, the chain of survival can produce survival rates approaching 50 percent in selected cases. Early Access The first link in the chain is early access. Generally, the sooner professional medical help arrives at the patient s side, the greater the potential for a successful outcome. Almost half of patients who suffer a cardiac arrest are not alone when the collapse occurs. Unfortunately, about half of the bystanders who witness an out-of-hospital cardiac arrest self-report a delay in recognizing the emergency and calling for help, thereby resulting in increased mortality. Early CPR The second link in the chain is early CPR. CPR is most effective when started immediately after the collapse. The patient is twice as likely to have a successful resuscitation when bystanders perform CPR before EMS providers arrive on the scene. However, in most cases of out-of-hospital cardiac arrest, no one provides CPR until EMS providers arrive on the scene. The most important component of CPR is high-quality chest compressions. Chest compressions permit blood and oxygen flow to the brain and vital organs by two mechanisms by directly squeezing the heart between the sternum and the spinal column and by increasing the pressure inside the chest cavity. For this reason, rescuers must begin high-quality chest compressions as quickly as possible for victims of cardiac arrest. Early Defibrillation The third link in the chain of survival is early defibrillation. For patients presenting in ventricular fibrillation, the interval from collapse to first shock is the single greatest determinant of survival. For every minute that passes while the patient is in ventricular 4

5 fibrillation, survival decreases by 7 10 percent. With that type of deterioration, it is easy to imagine a rapidly approaching threshold beyond which the chances of achieving a successful outcome for the patient approaches zero. The first three links in the chain of survival comprise basic life support skills. Bystanders and laypersons can utilize these initial interventions and potentially save a life before EMS personnel ever arrive on the scene. Advanced Cardiac Life Support Advanced cardiac life support is the fourth link in the chain. EMS personnel providing advanced life support measures at the scene can contribute to overall survival rates for out-of-hospital cardiac arrest. In the best of circumstances, however, if rescuers do not restore a pulse within 15 minutes of the beginning of the cardiac arrest, the patient will not survive. Integrated Post-Cardiac Arrest Care The newest link to the chain of survival for adult cardiac arrest is integrated postcardiac arrest care. Mounting evidence indicates that the immediate period following a return of spontaneous circulation is a key factor in determining the quality of the resuscitation outcome. For the EMS environment, key elements of this period include implementation of strategies to optimize hemodynamic function and vital organ perfusion, which includes transporting patients to facilities skilled in providing comprehensive post-cardiac treatment. Pediatric Chain of Survival The pediatric chain of survival is very similar to the adult chain of survival, with a few minor differences. Prevention of Cardiopulmonary Arrest The first link in the pediatric chain of survival is prevention of cardiopulmonary arrest. The leading causes of death for infants are congenital malformations, complications from premature birth, and sudden infant death syndrome. Trauma is the leading cause of death of children, with motor vehicle collision being the leading mechanism of injury. Unfortunately, survival from traumatic cardiac arrest is very rare, highlighting the importance of preventive measures. Healthcare providers can influence survival by advocating for targeted safety measures aimed at reducing trauma injuries in the pediatric population, such as child passenger safety seats. Early CPR The second link in the pediatric chain of survival is early CPR. Survival from cardiac arrest in the pediatric population is low. As in the adult population, CPR is most effective when initiated early. Researchers have reported survival rates of up to 70 percent in noncardiac-related arrest when bystanders begin CPR before the arrival of healthcare providers. Unfortunately, less than one-half of infants and children with out-of-hospital cardiac arrest receive bystander CPR. 5

6 Prompt Access to the Emergency Response System Prompt access to the emergency response system is the third link in the pediatric chain of survival. In cases where pediatric patients do not respond to the initial basic life support (BLS) maneuvers, access to a formal emergency response system offers the next best chance of a successful outcome. As in the adult population, this emergency response often involves accessing the system. Rapid Pediatric Advanced Life Support The fourth link in the pediatric chain of survival is rapid pediatric advanced life support. To maximize survival from out-of-hospital cardiac arrest, EMS providers must maintain expertise in pediatric assessment and stabilization. Unfortunately, most EMS responses involve adult patients. Some urban systems report fewer than 10 percent of their responses involve pediatric patients; even fewer involve seriously ill or injured cases, giving EMS personnel little opportunity to maintain competency. Integrated Post-cardiac Arrest Care The newest link to the pediatric chain of survival is integrated post-cardiac arrest care. Mounting evidence indicates that the immediate period following a return of spontaneous circulation is a key factor in determining the quality of the resuscitation outcome. For the EMS environment, key elements of this period include implementation of strategies to optimize hemodynamic function and vital organ perfusion. Learning Objective: Perform a high-quality CPR sequence, using the C-A-B model, on an adult patient How Does CPR Move Blood? The goal of CPR is to move oxygenated blood through a cardiovascular system that has become incapacitated for whatever reason. External closed chest compression have been used successfully for resuscitating people since 1858, but the first clinical proof of their efficacy did not come until over 100 years late. There are two primary theories that attempt to explain how external closed chest compression moves blood through the cardiovascular system the heart pump theory and the thoracic pump theory. Heart Pump Theory The first and oldest theory is known as the heart pump theory. This theory states that blood is forced out of the ventricles through direct compression of the heart between the sternum and the spinal column. During actual chest compression, however, most of the compressive force is to the right ventricle instead of the left ventricle. This action forces blood from the right side of the heart to the lungs but does not adequately explain how blood moves from the left ventricle. Thoracic Pump Theory The newest theory is called the thoracic pump theory. This theory suggests that compression of the sternum during CPR raises the pressure in the entire chest cavity 6

7 above the pressure that is outside of the cavity. After establishing this pressure gradient, venous collapse prevents a backflow of blood. Open arteries, especially under the influence of cardiac arrest medications, allow the force to push blood out of the chest. Both theories probably have some contribution to blood flow, but movement of blood out of the left ventricle is primarily caused by the thoracic pump theory. Harder and faster compressions increase the pressure to a greater degree, and more blood is delivered to the vital organs. Blood return to the heart is accomplished by the negative pressure that develops in the chest as the sternum and ribs rebound to their normal position during the decompression or relaxation phase. If healthcare providers achieve a greater amount of negative pressure in the chest by maximizing chest recoil, a greater amount of blood will return to the heart. Then, with the next compression, a greater amount will be forced to the lungs and other vital organs. Unfortunately, animal studies demonstrate that standard CPR performed with a 50 percent compression and 50 percent relaxation phase will produce only about percent of normal blood flow to the brain and only about 5 20 percent of normal blood flow to the heart. These low percentages, especially relating to perfusion of the heart muscle, may help to explain why resuscitation rates have historically been so low. It is easy to see that traditional CPR, even if performed flawlessly, may not be able to provide the perfusion necessary to maintain vital organ function and why healthcare providers must adopt a high-quality chest compression strategy. Adult BLS Sequence Before discussing the specific sequence of steps that form the BLS assessment and management of cardiac arrest, healthcare providers must understand that CPR training may not exactly mirror real-world responses to medical emergencies. The AHA uses an algorithmic approach to prioritize actions for rescuers. Algorithms, by nature, present sequential steps in a concise format, making the material easy to learn and remember. One limitation of the algorithmic approach is that it presents these steps with only one rescuer in mind. In reality, however, many rescuers respond in groups, thereby permitting performance of several actions simultaneously. Any trained healthcare provider can perform the simple steps associated with the BLS survey, which allows early detection and intervention in cases of cardiac arrest. The BLS survey does not include any advanced interventions that paramedics or emergency room personnel might use. It does, however, provide the springboard for these advanced providers to transition into more advanced resuscitation attempts. Basic life support interventions allow the healthcare provider to begin restoring some perfusion to the brain, heart muscle, and other vital organs until the patient regains normal circulatory function. The interventions associated with the BLS survey greatly improve the victim s chances of a full neurological recovery. 7

8 Because the out-of-hospital environment is uncontrolled and unpredictable, healthcare providers must always ensure their own safety before attempting to help the victim of a cardiac arrest. Healthcare providers will not be able to help the victim if they become injured, and that carelessness will only complicate matters. If unsafe conditions exist, the healthcare provider should not approach the scene. Instead, summon appropriate resources to make the scene safe before attempting to contact the patient. Recognition of the Arrest and Activation of the Emergency Response System In order to provide patients with early access to the healthcare system, rescuers must first recognize the presence of cardiac arrest and summon help. After ensuring that the scene is safe, rescuers should check to see if the patient is responsive. The recommended assessment step is for trained or untrained rescuers to tap the victim on the shoulder and shout, Are you all right? This action should startle a responsive victim, who will then answer, move, or moan. Consider any patient who does not respond to stimulation or does not move to be unresponsive. During the assessment for responsiveness, healthcare providers should simultaneously determine if the patient is breathing normally. This simple assessment can be accomplished by gazing across the victim s chest. If the breathing is absent or abnormal, or if the patient is gasping, the healthcare provider should assume the patient is in cardiac arrest and activate the emergency response system. Healthcare providers across many disciplines appear to have difficulty with the respiratory assessment, although EMS personnel are often more accurate in human and manikin simulations than are physicians and bystanders. Still, many healthcare providers spend too long trying to make a decision about whether patients are breathing adequately. This results in a delay in delivering chest compressions. The AHA recommends during the initial assessment for responsiveness, healthcare providers should not attempt to evaluate the quality of the patient s respiratory effort and instead should simply determine if absent or abnormal breathing is present and call for help. For unconscious patients with absent or abnormal breathing, healthcare providers should activate the emergency response system. In the realm of EMS, the person making the initial assessment is often a member of the emergency response system and it may seem silly to have this step for healthcare providers. However, in some cases, the only healthcare providers dispatched to the scene are on an ambulance. This step allows one rescuer to call for additional help and to retrieve an AED if it was not brought to the patient s side already. Pulse Check Several years ago, the AHA removed pulse checks from the assessment steps of lay rescuer CPR. Studies show that lay rescuers are not very accurate in determining whether a pulse is present. One study showed that it took at least 35 seconds for most lay rescuers to accurately detect the presence of a pulse. Other researchers demonstrated that lay rescuers trained in CPR often do not remember to perform circulatory assessment even 5 months after training. 8

9 Previous releases of the AHA Guidelines for CPR and ECC de-emphasized pulse checks for healthcare providers because studies show that medical professionals across a variety of disciplines have difficulty in accurately assessing for the presence of a pulse. One study showed that when limiting pulse checks to no more than 10 seconds, healthcare providers could correctly identify pulselessness only about half of the time. Increasing the pulse check to 30 seconds for those healthcare providers did not improve accuracy. The 2010 AHA Guidelines for CPR and ECC includes a pulse check as part of the initial healthcare provider assessment for unresponsive patients who are not breathing normally. However, the AHA cautions that healthcare providers must not spend too much time performing this action because of its questionable value. One study suggests that for unresponsive patients, pulse checks may provide diagnostic accuracy that is similar to checking for the presence of normal or abnormal breathing. To minimize the delay in providing chest compressions, healthcare providers should take no longer than 10 seconds to assess for the presence of a pulse. If the pulse is absent or if the healthcare provider is unsure, he or she should begin chest compressions immediately. Perform Chest Compressions One key change in the 2010 AHA Guidelines for CPR and ECC is in the sequence of chest compressions and ventilation. Although there is no clear evidence that beginning the CPR sequence with chest compressions increases the likelihood of return of spontaneous circulation or improves neurological outcome, victims will not have forward blood flow during cardiac arrest unless someone performs chest compressions. For that reason, it is reasonable to adopt an intervention strategy that reduces delays in delivering chest compressions. Focusing on a sequence that starts with chest compressions effectively changes the time-honored airway-breathing-circulation, or A-B-C, approach to a circulation-airway-breathing, or C-A-B, approach. It is also reasonable for healthcare providers not to immediately move the patient to the ambulance for transport to the hospital. In one study, researchers divided 10 EMS personnel into five teams. Each team performed chest compressions-only (no ventilations) in two scenarios on a manikin capable of detecting proper hand placement and compression depth. In the stationary scenario, the team performed 5 minutes of continuous chest compressions with the manikin in the floor. In the mobile scenario, the team performed 5 minutes of continuous chest compressions with the manikin on a stretcher in the back of a moving ambulance. During the mobile scenario, the driver did not activate the lights or siren and was required to obey all traffic laws. Each team performed each scenario twice. In the final analysis, the stationary EMS personnel pushed to the correct depth in 78 percent of the compressions compared with only 45 percent of the compressions in the mobile group. Because providing high-quality chest compressions is difficult during movement, healthcare providers should generally conduct a stationary resuscitation attempt at the location where the patient collapsed unless a threat to the healthcare providers safety exists. 9

10 Healthcare providers provide the most effective chest compressions when kneeling next to the victim and placing the heel of the dominant hand on the lower half of the sternum. Healthcare providers should then place the heel of the other hand on top of and parallel to the dominant hand. The healthcare provider s shoulders should be along the patient s midline, with arms straight, and elbows locked. When compressing, healthcare providers should push hard and push fast, to a depth of at least 2 inches in the adult victim. Researchers demonstrated that if rescuers provide a defibrillation shock within 3 minutes of collapse, pre-shock chest compressions greater than 2 inches in depth double survival compared with more shallow preshock compressions. If rescuers deliver the first shock at greater than 5 minutes, chest compressions deeper than 2 inches triple survival compared to shallow compressions. After compression, allow the chest to recoil completely as this phase is the period where the heart refills with blood. Incomplete recoil reduces the effectiveness of CPR. The actual number of chest compressions that healthcare providers deliver during each minute of the resuscitation attempt is an important factor in achieving a return of spontaneous circulation. The 2010 AHA Guidelines for CPR and ECC recommend that healthcare providers push at a rate of at least 100 compressions per minute, although the periodic pauses for rescue breathing will reduce the number of chest compressions actually delivered to fewer than 100. Although two hallmarks of high-quality CPR include pushing hard and fast while maximizing chest recoil, CPR performance measurements on manikins demonstrate the difficulty in achieving these goals. When performing standard CPR on a manikin, trained bystanders achieve adequate depth only about one-third of the time and complete chest wall recoil one-fourth of the time. Even when prompted by a metronome or when CPR performance periods were short, various hand positioning strategies resulted in a wide variation of compression rates among trained bystanders. Unfortunately, professional rescuers do not fare much better. Researchers tested the CPR skills of 66 firefighters, EMTs, and paramedics, including some who were certified as CPR instructors. Each rescuer performed CPR for 1 minute on a manikin instrumented to measure CPR performance. Only one-fourth of the chest compressions provided by the rescuers met the guidelines for proper depth and recoil. Additionally, the rescuers delivered about two-thirds of the compressions in the wrong place on the chest. Lay rescuers who are not comfortable with performing both compressions and ventilations can perform hands-only CPR. Even though this form of CPR does not include a ventilation component, it may still be effective for some patients. In the early stages of the cardiac arrest, ventilation may not be as important because adequate oxygen levels remain in the blood stream. In fact, some studies have observed similar survival rates for victims of cardiac arrest who received hands-only CPR compared with traditional CPR that included ventilation. At some point during the resuscitation attempt, 10

11 rescuers will likely have to replenish the oxygen levels. However, the interval during which hands-only CPR remains acceptable is unknown. Ventilate the Patient After delivering 30 high-quality chest compressions, healthcare providers and lay rescuers who are comfortable with the technique should open the patient s airway using a head-tilt, chin-lift method. A small number of patients with blunt traumatic injury will have an associated cervical spine injury, making this method of airway control potentially dangerous. In cases of suspected cervical spine injury, healthcare providers should use a jaw thrust without head extension. However, healthcare providers should return to the head-tilt, chin-lift methods if the jaw thrust does not provide an open airway. Once the airway is open, healthcare providers should deliver two rescue breaths using a bag-mask device. Although seemingly simple, effective use of the bag mask requires considerable practice in order to achieve competency. Each breath should be about 1 second in duration, with enough volume to produce visible chest rise. Delivering greater tidal volumes can force air into the patient s stomach, which reduces the effectiveness of ventilation and could promote vomiting and aspiration. Excessive ventilation also increases the pressure within the chest cavity, thereby reducing blood return to the heart, reducing cardiac output with chest compression, and decreasing survival. Learning Objective: List two impediments to performing highquality CPR Rescuer Fatigue After delivering two rescue breaths, the healthcare provider should move back to the chest and resume high-quality chest compressions within 10 seconds. The recommended compression-ventilation ratio for adult victims of cardiac arrest is 30 compressions to two ventilations. Basic life support providers should continue CPR until the AED arrives, advanced level providers take over care of the patient, or the patient awakes. The effectiveness of CPR is highly variable. Many factors can decrease the healthcare provider s ability to perfuse the patient s brain and heart during CPR. In order to maximize the patient s chances of survival, healthcare providers must perform CPR as effectively as possible throughout the entire resuscitation effort. This point cannot be stressed enough. Multiple healthcare providers on the scene should switch chest compressors every 2 minutes coinciding with a pulse check and AED rhythm analysis. Properly performed CPR can easily create rescuer fatigue, which can decrease the effectiveness of the resuscitation effort. In a manikin study of one-rescuer CPR, the percentage of compressions deemed as correct fell from 92.9 percent during the first minute to 18 11

12 percent during the fifth minute. In this study, the healthcare providers (blinded to the results) believed that they were able to maintain 90 percent effectiveness throughout the 5-minute period. Follow-up studies using the same methodology produced similar results. Interruptions Switching chest compressors accounts for a significant portion of the total no-flow time that occurs during a cardiac arrest. Healthcare providers should attempt to accomplish the switch in fewer than 5 seconds. If three or more healthcare providers are present on the scene, one can take a position across from the chest compressor. When the compressor signals, the new compressor can resume compressions immediately. Recent studies have demonstrated the importance of continuous chest compressions during CPR. Animal models indicate a decrease in survivability when chest compressions are interrupted for as little as 20 seconds. The animals that did survive often showed a decrease in post-resuscitation myocardial function. Human studies have demonstrated that longer pre-shock interruptions in chest compressions result in less effective defibrillation. There are many other sources of interruptions in chest compressions that may represent one-fourth to one-half of the total arrest interval. These interruptions may reduce the chances of having a successful outcome. Healthcare providers should orchestrate the resuscitation effort with a focus on minimizing interruptions in chest compressions. When interruptions do occur, to provide defibrillation for example, healthcare providers should limit the interval to no more than 10 seconds. The risk/benefit of ventilation during CPR has also been evaluated, and recent experimental data suggest that rescue breathing may be having a harmful effect, in part because ventilation interrupts chest compression. Another drawback appears to be that positive pressure ventilation, especially overzealous ventilation, prohibits the development of negative pressure within the chest cavity, thereby reducing blood return to the right heart and reducing the overall blood flow that can be generated with CPR. In one animal study, excessive ventilation during CPR resulted in increased pressure accumulations in the chest, a decrease in perfusion to the heart muscle, and lower survival rates. Learning Objective: Demonstrate the steps in the proper use of an automated external defibrillator Early Defibrillation With an AED The third link in the chain of survival is early defibrillation. In general, for patients who develop a lethal ventricular rhythm, survival rates are highest when rescuers can provide defibrillation within 3 5 minutes of collapse. When alone, healthcare providers who determine that a victim is unconscious with absent or abnormal breathing should activate the emergency response system and get an AED, if it is nearby and eas- 12

13 ily accessible. Upon returning to the victim, the healthcare providers should attach the AED and follow the voice prompts. When directed by the AED, the healthcare providers should begin high-quality CPR. When two healthcare providers are present, one should immediately begin chest compressions after determining unresponsiveness while the other activates the emergency response system and gets the AED. When the AED arrives at the victim s side, one healthcare provider should continue CPR while the other attaches the AED. At that point, both healthcare providers should follow the AED voice prompts. When directed by the AED, both healthcare providers should provide high-quality CPR. Automated External Defibrillators An AED is a machine with a rhythm analysis system capable of accurately determining whether a patient is experiencing a shockable rhythm. The device is also capable of delivering the shock either automatically or by the user. Some newer models of AEDs are capable of monitoring how deep and how fast healthcare providers perform chest compressions and can prompt rescuers to improve the quality of their CPR. To determine whether a shockable rhythm is present, the software within the AED analyzes multiple characteristics of the electrocardiogram (ECG) signal. Researchers have tested the rhythm analysis software extensively in both adults and children and demonstrated accuracy. There are actually two different types of AEDs fully automated and semi-automated. The semi-automated machines require an operator to press a button to deliver a shock. This AED operator is responsible for ensuring the safety during the energy discharge. The fully automated AED will discharge automatically after warning rescuers to stand back. Healthcare providers who are unsure of exactly which type of machine they are using are encouraged to heed the warnings of the voice prompt and stand back when instructed to do so. As soon as an AED is available on the scene, one healthcare provider should place the machine at the victim s head. This allows the healthcare provider who is operating the machine to maintain visual contact with both the AED s controls and the patient s chest. This also allows another healthcare provider to perform chest compressions on the opposite side of the AED without interfering with the machine s operation. There are varieties of AED manufacturers and each model may have different features; however, all AEDs operate in essentially the same way using four universal steps. Step 1: Activating the AED Power The first step is to activate the AED power. Turning on the AED allows the voice prompts to begin, which can lead healthcare providers and other rescuers through the steps for safe and effective operation of the device. Some models of AED turn on as soon as the rescuer opens the lid or case. Other models have an easily recognizable button that activates the device. 13

14 Step 2: Attaching the Defibrillation Pads After coming on, the voice prompt will usually direct the healthcare provider to the second universal step attaching the defibrillation pads to the patient s bare chest. Some AED designs automatically adjust energy doses for adult patients or pediatric patients depending upon which set of pads rescuers place on the patient s chest. For this reason, if the AED has two sizes of pads available, healthcare providers must attach the correct pads to the patient s chest. In general, adult-sized pads are appropriate for all victims over the age of 8 years old. Attaching pediatric pads to an adult chest will result in an energy dose that is not likely to be effective. If the patient s chest is wet or sweaty, quickly wipe the surface dry before attaching the pads. Most AED pads have a drawing that illustrates the correct placement position. Generally, one pad belongs on the patient s right upper chest just below the clavicle and to the right of the sternum. The second pad goes under the left arm a few inches from the armpit. Healthcare providers should peel the protective backing off the pad and push the adhesive side firmly into the patient s chest while ensuring tight contact. Pads that are not firmly attached to the patient s chest may interfere with the operation of the device. If the AED pad cable is loose, healthcare providers should plug in the pad connector to the machine. In some models, however, the cable is already preconnected. Step 3: Analyzing the Rhythm The third universal step is to analyze the rhythm. Some AEDs will automatically analyze, while others will direct a member of the healthcare team to push a button to start the analyzing process. In most cases, the AED voice prompt will direct healthcare providers to stop chest compressions and avoid all contact with the patient. Healthcare providers must ensure that no one touches the patient while the machine is analyzing the heart rhythm to prevent interruption of the analysis or an error in rhythm interpretation. Newer AED models are capable of analyzing the rhythm within 5 15 seconds. At the end of the analysis period, the voice prompt will indicate whether a shock is recommended or not. If the AED indicates that no shock is advised, the healthcare provider should immediately begin chest compressions. Other healthcare providers should not remove the AED pads or turn off the AED. The machine will start an internal countdown from 2 minutes to allow the team to provide high-quality CPR. At the end of the countdown, the AED voice prompt will start the analysis sequence again. Step 4: Delivering the Shock In cases where the AED recommends a shock, most AEDs will begin charging automatically and the device prepares for the fourth universal step delivering the shock. Once the charging sequence begins, healthcare providers cannot usually interrupt the process. This is important because healthcare providers should provide chest compressions while the machine is charging. When the machine is fully charged and ready to deliver the shock, the healthcare provider operating the AED should loudly and clearly announce that everyone should clear and avoid contact with the patient. 14

15 One clearing sequence recommended by the AHA is for the healthcare provider to say, Clear! I m going to shock on three one two three. During the shock countdown, the healthcare provider should look to see that no one is in contact with the patient and deliver the shock appropriately. As the energy dose travels through the patient s chest, some sudden muscle contraction occurs and is typically visible as jerking in the patient s arms. As soon as the shock is delivered, one healthcare provider should resume chest compressions as quickly as possible. Do not delay chest compressions to check for a pulse or to perform a second rhythm analysis. The AED will begin a 2-minute countdown. The healthcare provider should perform high-quality CPR during this time. At the end of the countdown, the voice prompt will begin the analysis sequence again to see if the patient needs an additional shock. AEDs that fail to work properly are usually the result of operator error rather than a machine malfunction. Healthcare providers who are unfamiliar with the AED are more likely to have operator error. It is therefore important for all healthcare providers to have some familiarity with the basic design of the machine they will most likely have access to in the event of a cardiac arrest. If the AED fails to deliver a shock when indicated, healthcare providers should immediately resume high-quality CPR. Do not delay chest compressions while trying to troubleshoot the AED. AED Safety Because the energy delivered during defibrillation is capable of causing serious injury to the healthcare providers in contact with the patient, it is important for those operating the AED to use them safely. The AED operator must ensure that no one is in contact with the patient during energy delivery. The AHA recommends that the AED operator announce loudly and forcefully that a shock is imminent using this simple process. First, announce, I m going to shock on three. Simultaneously, visually verify that no one is touching the patient, the stretcher, or any other conductive equipment in contact with the patient. Make sure that oxygen is flowing directly across the patient s chest. A shock that produces an electrical spark in a high-oxygen concentration environment could result in a fire on the patient s clothing. Then, countdown, One two three. Shocking now! The AED operator should face the patient when delivering the shock to ensure that no one resumed contact with the patient either prematurely or accidentally. To review the universal steps in AED use: Step 1: Turn the AED on. The voice prompts will begin as soon as the AED is on. Some AEDs are activated as soon as the healthcare provider opens the machine. Others require the healthcare provider to activate the device. Step 2: Attach the AED pads to the patient s bare chest and plug in the pads connector to the machine. 15

16 Step 3: Analyze the patient s heart rhythm. Do not allow anyone to have contact with the patient during this analysis. Step 4: Deliver the shock. Make sure no one is in contact when delivering the energy dose. As soon as the shock is delivered, or the voice informs that no shock is indicated, the healthcare provider should immediately provide high-quality CPR beginning with chest compressions. Pediatric Defibrillation Although pediatric cardiac arrests are more likely to be asphyxial in nature, sudden collapse from lethal ventricular arrhythmia in the pediatric population does occur. In addition, researchers estimate that a number of victims presenting in a non-shockable cardiac arrest rhythm will develop ventricular fibrillation during the resuscitation attempt. Several anatomic and physiologic differences between adults and children may influence the overall effectiveness of defibrillation attempts. Children s hearts are much smaller than are those of an adult. Producing and sustaining ventricular fibrillation requires that a certain amount of the myocardial mass must be involved. Since children have a much smaller myocardial mass, this may help explain why the incidence of pediatric ventricular fibrillation is low compared with adults. Children also have faster heart rates, lower stoke volumes, and higher cardiac output per kilogram of body weight than adults. However, oxygen demand is higher in children, which leaves them with lower oxygen reserves. Myocardial tissue, then, will be depleted of oxygen relatively faster than in the adult. Researchers have demonstrated that adult AEDs are accurate in recognizing shockable rhythms in pediatric patients. Many AEDs are equipped with features that allow a reduction or attenuation in energy delivery for pediatric patients. In most cases, this occurs with specialized defibrillation pads that healthcare providers attach to the pediatric chest. The preferred method of defibrillation in the infant, however, is manual defibrillation by healthcare providers trained to recognize shockable rhythms. In cases where manual defibrillation is not possible, healthcare providers should use an AED with a pediatric attenuator for patients up to 8 years old. Beyond that age, healthcare providers should use an AED with adult defibrillation pads. If no pediatric attenuator is available, healthcare providers may attach a conventional AED to infants and children age 8 years old. After attaching the AED, healthcare providers should follow the voice prompts. Special Situations Sometimes, special situations arise that force healthcare providers to alter the way they use an AED. Hairy Chest A hairy chest can interfere with the AED pad contact and prevent analysis of the patient s heart rhythm. Many AEDs are designed to prompt the healthcare provider to check the electrode connection. If the AED voice prompt gives that message, one healthcare provider should immediately resume chest compressions while another healthcare provider attempts to correct the situation. 16

17 First, the healthcare provider should attempt to push the adhesive pads more firmly into the patient s chest. If this does not correct the problem and the AED continues prompting the healthcare provider to check the electrodes, the rescuers should quickly pull the pads off the chest, which should remove a significant amount of hair. Before attaching a second set of pads, inspect the area. If there is still a considerable amount of hair, many AED cases have a small disposable razor that the healthcare provider could quickly use to bare an area for pad placement. Once the area is clean, the healthcare provider should attach the second set of pads and follow the AED voice prompts. Wet Victims Never use an AED while the patient is still in the water. Quickly remove the victim from the water (if it is safe to do so) and place him or her on a firm surface. One healthcare provider should begin chest compressions while a second rescuer quickly dries the patient s chest. Water present on the patient s chest could conduct the electrical current and render the shock ineffective. As soon as the chest is dry, place the AED pads as normal and follow the AED voice prompts. After rescuing the victim from the water, it is safe to use the AED as long as the chest is dry. Do not delay AED use to remove wet clothing (except if the clothing covers the chest), to dry the patient s hair, or to move the victim off a wet towel. It is also safe to use an AED on a victim who is lying on snow. Patients With Implanted Pacemakers Current technology allows doctors to implant surgically small defibrillators into patients with a high-risk for developing lethal ventricular arrhythmias. An internal cardiac defibrillator (ICD) is very similar to an external AED in that it constantly monitors the patient s heart rhythm. If the ICD detects a shockable rhythm, the device will deliver a charge directly to the heart muscle. Patients who have ICDs will have a small lump about the size of a silver dollar or a half-deck of playing cards that can be felt under the skin in the chest or upper abdomen. On the skin covering the lump will be a small scar. If the patient has one of these implanted devices and is pulseless, healthcare providers should attach the AED just as they would for any other patient. The only modification the healthcare provider might need to make is in pad placement. Do not place an AED pad directly over the lump because the device can interfere with the energy delivery to heart. Instead, place the pad at least 1 inch away from the lump and follow the AED voice prompts as normal. If the AED recommends a shock, the healthcare provider should deliver the energy. On occasion, the internal defibrillator will continue to shock the patient as the healthcare provider is attaching the external AED to the patient s chest. When that happens, the healthcare provider will see some muscle contractions that resemble those seen with an external shock. If that happens, the AHA recommends that healthcare providers continue CPR and wait 30 seconds after the internal device shocks before attempting to deliver an external shock. 17

18 Transdermal Medication Patches One method of medication delivery involves absorption directly across the skin. Patients may place the medication as an ointment in a small area of the chest and cover it with an adhesive patch. In other cases, the medication is impregnated onto a patch that is placed on the skin. In either case, the medication or the patch can interfere with energy conduction from an AED or result in burned areas of the chest. If the patient has a transdermal medication patch on the chest in an area where the healthcare provider intends to place an AED pad, remove the patch and wipe the area clean before attaching the pad. Do not place an AED pad directly over a medication patch. Learning Objective: Perform a high-quality CPR sequence, using the C-A-B model, on a pediatric patient Pediatric CPR Although following a C-A-B model of CPR allows healthcare providers to initiate chest compressions sooner, asphyxial arrest is much more common in children. At least one pediatric study demonstrated improved outcomes with compressions and ventilations following asphyxial arrest. However, the benefits of a pediatric CPR sequence that provides ventilation before chest compression remains unclear. To simplify CPR training for all rescuers, the AHA adopted the C-A-B approach for pediatric patients in addition to adult patients. For the purposes of CPR guidelines, the AHA defines the victim in this manner. Infant CPR guidelines apply to infants up to approximately 1 year of age. Child CPR guidelines apply to children from approximately 1 year of age to the onset of puberty. The AHA defines puberty for the purposes of CPR as breast development in girls and the presence of underarm, chest, or facial hair in boys. Adult CPR guidelines apply to anyone who has reached puberty Pediatric BLS Sequence Although there are many similarities between adult and pediatric CPR, there are some important differences. Healthcare providers should begin by determining if the child is unresponsive by gently tapping the child and asking loudly, Are you OK? This action should startle a responsive victim, who will then answer, move, or moan. If the infant or child does not respond to stimulation or does not move, consider the victim unresponsive. Simultaneously with the assessment for unresponsiveness, determine if the victim has evidence of normal breathing. If breathing is absent or is abnormal, which includes gasping, healthcare providers should begin chest compressions immediately. Healthcare providers should assess the brachial pulse in an infant and the carotid or femoral pulse in a child. If the healthcare provider does not feel a pulse or is unsure whether a pulse is present after a 10-second check, he or she should immediately begin chest compressions. 18

19 Chest Compressions Just as in the adult patient, rescuers improve blood flow to the victim s vital organs by providing high-quality chest compressions on a firm surface. For infants, healthcare providers should place two fingers on the victim s chest just below the intermammary line. Push hard to a depth of about one-third the anterior-posterior diameter of the chest, which is equal to about 1.5 inches in the infant. Push fast at a rate of at least 100 compressions per minute. After compression, healthcare providers must allow maximum recoil of the victim s chest to allow the heart to adequately refill with blood. Healthcare providers should deliver 30 chest compressions. For children, healthcare providers should place the heel of one hand on the lower half of the victim s chest just below the intermammary line. Push hard to a depth of about one-third the anterior-posterior diameter of the chest, which is equal to about 2 inches in children. If the healthcare provider finds it too difficult to push to the recommended depth with one hand, the rescuer should place the second hand on top of the first hand, which can produce high compression pressure. Push fast at a rate of at least 100 compressions per minute. After compression, healthcare providers must allow maximum recoil of the victim s chest to allow the heart to adequately refill with blood. If more than one healthcare provider is performing CPR on an infant, the AHA recommends a two-thumb-encircling hands technique. This modification to the traditional two-finger compressions advocated for single healthcare provider CPR may generate higher systolic and diastolic pressures. One healthcare provider should place both thumbs on the lower third of the patient s sternum and spread the fingers to encircle the thorax. The healthcare provider should forcefully compress the infant s chest with the thumbs. Previous guidelines recommended that the healthcare provider also squeeze the thorax with each compression; however, there is no compelling evidence demonstrating a benefit from a circumferential thoracic squeeze. Ventilation A single healthcare provider should deliver 30 chest compressions and follow with two rescue breaths. Open the airway with the head-tilt, chin-lift technique. The healthcare provider should use his or her mouth to cover the infant s nose and mouth or the child s mouth and blow for 1 second with the minimum amount of force necessary to produce chest movement. If the first breath does not produce chest rise, reposition the victim s head and try again. Following the two assisted ventilations, healthcare providers should move back to the victim s chest and resume compressions. The AHA recommends a compressionto-ventilation ratio of 30:2 for single healthcare providers, although the optimal ratio is still unidentified. Rescuers should minimize interruptions in chest compressions as blood flow to the heart rapidly declines when chest compressions stop. Single healthcare providers should provide five cycles of 30 compressions and two ventilations before activating the emergency response system. 19