Chapter 17 Cardiac Emergencies

Chapter 17 Cardiac Emergencies

U.S. DOT Objectives Directory
U.S. DOT Objectives are covered and/or supported by the PowerPoint™ Slide Program and Notes for Emergency Care, 11th Ed. Please see the Chapter 17 correlation below. *KNOWLEDGE AND ATTITUDE 4-3.1 Describe the structure and function of the cardiovascular system. Slides 10-16 4-3.2 Describe the emergency medical care of the patient experiencing chest pain or discomfort. Slides 30-41, 43 4-3.3 List the indications for automated external defibrillation (AED). Slides 55, 57, 59 4-3.4 List the contraindications for automated external defibrillation. Slides 56, 58, 65, 69 4-3.5 Define the role of EMT in the emergency cardiac care system. Slides 30-92 4-3.6 Explain the impact of age and weight on defibrillation. Slide 86 4-3.7 Discuss the position of comfort for patients with various cardiac emergencies. Slide 31 (cont.)

*KNOWLEDGE AND ATTITUDE 4-3.8 Establish the relationship between airway management and the patient with cardiovascular compromise. Slides 50, 73, 82, 86 4-3.9 Predict the relationship between the patient experiencing cardiovascular compromise and basic life support. Slides 41-50 Discuss the fundamentals of early defibrillation. Slides 44, 47 Explain the rationale for early defibrillation. Slides 44, 47 Explain that not all chest pain patients result in cardiac arrest and do not need to be attached to an automated external defibrillator. Slide 43 Explain the importance of prehospital ACLS intervention if it is available. Slide 48 Explain the importance of urgent transport to a facility with advanced cardiac life support if it is not available in the prehospital setting. Slides 33-34 Discuss the various types of automated external defibrillators. Slides 53-54 (cont.)

*KNOWLEDGE AND ATTITUDE Differentiate between the fully automated and the semiautomated defibrillator. Slide 53 Discuss the procedures that must be taken into consideration for standard operations of the various types of automated external defibrillators. Slides 55-79 State the reasons for assuring that the patient is pulseless and apneic when using the automated external defibrillator. Slide 59 Discuss the circumstances which may result in inappropriate shocks. Slide 56 Explain the considerations for interruption of CPR when using the automated external defibrillator. Slides 60-62, 77 Discuss the advantages and disadvantages of automated external defibrillators. Slide 53 Summarize the speed of operation of automated external defibrillation. Slide 53 (cont.)

*KNOWLEDGE AND ATTITUDE Discuss the use of remote defibrillation through adhesive pads. Slide 54 Discuss the special considerations for rhythm monitoring. Slides 57-58 List the steps in the operation of the automated external defibrillator. Slides 64-76 Discuss the standard of care that should be used to provide care to a patient with persistent ventricular fibrillation and no available ACLS. Slides 51-88 Discuss the standard of care that should be used to provide care to a patient with recurrent ventricular fibrillation and no available ACLS. Slides 51-88 Differentiate between single rescuer and multi-rescuer care with an automated external defibrillator. Slide 85 Explain the reason for pulses not being checked between shocks with an automated external defibrillator. (cont.)

*KNOWLEDGE AND ATTITUDE Discuss the importance of coordinating ACLS trained providers with personnel using automated external defibrillators. Slides 80-81 Discuss the importance of post-resuscitation care. Slides 82-84 List the components of post-resuscitation care. Slides 82-84 Explain the importance of frequent practice with the automated external defibrillator. Slide 92 Discuss the need to complete the Automated Defibrillator: Operator’s Shift Checklist. Slide 91 Discuss the role of the American Heart Association (AHA) in the use of automated external defibrillation. Slide 44 Explain the role medical direction plays in the use of automated external defibrillation. Slide 92 State the reasons why a case review should be completed following the use of the automated external defibrillator. Slide 92 Discuss the components that should be included in a case review. Slide 92 (cont.)

*KNOWLEDGE AND ATTITUDE Discuss the goal of quality improvement in automated external defibrillation. Slide 92 Recognize the need for medical direction of protocols to assist in the emergency medical care of the patient with chest pain. Slides 35-36, 38-40, 92 List the indications for the use of nitroglycerin. Slides 36-37 State the contraindications and side effects for the use of nitroglycerin. Slides 36-37 Define the function of all controls on an automated external defibrillator, and describe event documentation and battery defibrillator maintenance. Slides 67, 70-71, 74 Defend the reasons for obtaining initial training in automated external defibrillation and the importance of continuing education. Slide 92 Defend the reason for maintenance of automated external defibrillators. Slide 91 (cont.)

*KNOWLEDGE AND ATTITUDE Explain the rationale for administering nitroglycerin to a patient with chest pain or discomfort. Slides 35-40 (cont.)

*SKILLS Demonstrate the assessment and emergency medical care of a patient experiencing chest pain or discomfort. Demonstrate the application and operation of the automated external defibrillator. Demonstrate the maintenance of an automated external defibrillator. Demonstrate the assessment and documentation of patient response to the automated external defibrillator. Demonstrate the skills necessary to complete the Automated Defibrillator: Operator’s Shift Checklist. Perform the steps in facilitating the use of nitroglycerin for chest pain or discomfort. Demonstrate the assessment and documentation of patient response to nitroglycerin. Practice completing a prehospital care report for patients with cardiac emergencies.

Virtual Tours and Animations
Click here to view a virtual tour of the respiratory system. Click here to view a virtual tour of the heart. Click here to view a virtual tour of the head and neck. Click here to view a virtual tour of the trunk and abdomen. Click here to view an animation of the heart. Click here to view an animation of cardiovascular emergencies. 10

Review of Circulatory System
The cardiovascular system consists of the heart and the blood vessels through which blood is circulated throughout the body. It is also called the circulatory system. 11

Cross-Section of the Heart
The human heart is a muscular organ about the size of your fist, located in the center of the thoracic cavity. The heart has four chambers: two upper chambers called atria and two lower chambers called ventricles. The atria both contract at the same time. When they contract, blood is forced into the heart’s lower chambers, the ventricles. Both ventricles contract simultaneously to pump the blood out of the heart. The path the blood takes on its journey through the body is as follows: right atrium to right ventricle to lungs to left atrium to left ventricle to body, then back to the right atrium to start its journey all over again. Between each atrium and ventricle is a one-way valve to prevent blood in the ventricle from being forced back up into the atrium when the ventricle contracts. The pulmonary artery has a one-way valve so that blood in the artery does not return to the right ventricle. The aorta also has a one-way valve to prevent backflow to the left ventricle. This system of one-way valves keeps the blood moving in the correct direction along the path of circulation. 12

The Four Chambers of the Heart
Right Atrium Left Atrium Receives blood from veins; pumps to right ventricle. Receives blood from lungs; pumps to left ventricle. Right Ventricle Left Ventricle Right atrium. The venae cavae (the superior vena cava and the inferior vena cava) are the two large veins that return blood to the heart. The right atrium receives this blood and, upon contraction, sends it to the right ventricle. Right ventricle. The right ventricle receives blood from the chamber above it, the right atrium. When the right ventricle contracts, it pumps this blood out to the lungs via the pulmonary arteries. Remember, this blood is very low in oxygen and is carrying waste carbon dioxide that was picked up as the blood circulated through the body. While this blood is in the lungs, the carbon dioxide is excreted (taken out of the blood and when the person exhales, carried out of the body), and oxygen is obtained (taken into the blood from air the person has inhaled). The oxygen-rich blood is now returned to the left atrium via the pulmonary veins. Left atrium. The left atrium receives the oxygen-rich blood from the lungs. When it contracts, it sends this blood to the left ventricle. Left ventricle. The left ventricle receives oxygen-rich blood from the chamber above it, the left atrium. When it contracts, it pumps this blood into the aorta, the body’s largest artery, for distribution to the entire body. Since the blood must reach all parts of the body, the left ventricle is the most muscular and strongest part of the heart. Pumps blood through the aorta to the body. Pumps blood to the lungs. 13

Cardiac Conduction System
The contraction, or beating, of the heart is an automatic, involuntary process. The heart has its own natural “pacemaker” and a system of specialized muscle tissues that conduct electrical impulses that stimulate the heart to beat. This network is called the cardiac conduction system (Figure 4-14). Regulation of rate, rhythm, and force of heartbeat comes, in part, from the cardiac control centers of the brain. Nerve impulses from these centers are sent to the pacemaker and conduction system of the heart. These nerve impulses and chemicals (epinephrine, for example) released into the blood control the heart’s rate and strength of contractions. The Conduction System Sinoatrial node Site of impulse formation Internodal tracts provide impulse transmission across both atria and also to the AV node Intrinsic rate 60–100 bpm Atrioventricular node Temporarily slows impulse before it reaches the ventricles Intrinsic rate 40–60 bpm Bundle of His Connects the AV node to the bundle branches Intrinsic rate 20–40 bpm Right and left bundle branches Transmit the impulse from the AV node to each of the two ventricles Purkinje fibers Terminal portion of the conduction system that provides the electrical impulse to the contractile cells of the ventricles This allows organized contraction of the ventricles. Intrinsic rate less than 20 bpm 14

The Coronary Arteries The coronary arteries branch off from the aorta and supply the heart muscle with blood. Although the heart has blood constantly moving through it, it receives its own blood supply from the coronary arteries. Damage or blockage to these arteries usually results in chest pain. Important to note are the coronary arteries, which are the first arteries to arise from the aorta, and provide perfusion to the myocardium. Partial or full occlusion of these arteries is what precipitates cardiovascular compromise in patients. When the heart does not receive a constant supply of oxygenated blood, cells begin to malfunction or cease to function. 15

Vessels of Circulation
When the blood leaves the heart, it travels throughout the body through several types of blood vessels. Blood vessels are described by their function, location, and whether they carry blood away from or to the heart. The kind of vessel that carries blood away from the heart is called an artery. Arteries begin with large vessels, like the aorta. They gradually branch to smaller and smaller vessels. The smallest branch of an artery is called an arteriole. These small vessels lead to the capillaries. Capillaries are tiny blood vessels found throughout the body. As explained earlier, the capillaries are where gases, nutrients, and waste products are exchanged between the body’s cells and the bloodstream. From the capillaries the blood begins its return journey to the heart by entering the smallest veins. One of these small veins is called a venule. The kind of vessel that carries the blood from the capillaries back to the heart is called a vein. Remember that the blood flow from the heart started in the largest arteries and moved into smaller and smaller arteries until it reached the capillaries. The blood takes an opposite course through the veins. The blood travels from the smaller to the larger vessels on its return trip to the heart. Immediately after leaving the capillaries, the blood enters venules, the smallest veins. From the venules, the veins get gradually larger, eventually reaching the venae cavae. 16

Cardiac Compromise Cardiac compromise is a blanket term that refers to any kind of problem with the heart. There are many different ways in which patients’ hearts show that they are in trouble. One reason for this is that there are many different kinds of problems the heart can experience. A coronary artery may become narrowed or blocked, a one-way valve may stop working properly, or the specialized tissue that carries electrical impulses may function abnormally. You may also hear cardiac compromise called acute coronary syndrome (ACS). 17

Causes of Cardiac Compromise
Arteriosclerosis Atherosclerosis Two conditions, atherosclerosis and arteriosclerosis, commonly cause the narrowing or blockage of arteries. Atherosclerosis is a build-up of fatty deposits on the inner walls of arteries. This build-up causes a narrowing of the inner vessel diameter, restricting the flow of blood. Fats and other particles combine to form this deposit, known as plaque. As time passes, calcium can be deposited at the site of the plaque, causing the area to harden. Arteriosclerosis is a stiffening or hardening of the artery wall resulting from calcium deposits. Often called “hardening of the arteries,” this condition causes the vessel to lose its elasticity, changing blood flow and increasing blood pressure. (cont.) 18

Aneurysms Another cause of cardiovascular system disorder stems from weakened sections in the arterial walls. Each weak spot that begins to dilate (balloon) is known as an aneurysm. This weakening can be related to other arterial diseases, or it can exist independently. When a weakened section of an artery bursts, there can be rapid, life-threatening internal bleeding. Tissues beyond the rupture can be damaged because the oxygenated blood they need is escaping and not reaching them. If a major artery ruptures, death from shock can occur very quickly. When an artery in the brain ruptures, a severe form of stroke occurs. The severity is dependent on the site of the stroke and the amount of blood loss. (cont.) 19

Electrical Malfunctions of the Heart
Causes of Cardiac Compromise Electrical Malfunctions of the Heart Bradycardia Less than 60 beats per minute Tachycardia Greater than 100 beats per minute No pulse Cardiac arrest Electrical impulses generated within the heart are responsible for the rhythmic beating of the heart that pumps blood throughout the body. A malfunction of the heart’s electrical system will generally result in a dysrhythmia, an irregular, or absent heart rhythm. Dysrhythmias include bradycardia (abnormally slow, less than 60 beats per minute), tachycardia (abnormally fast, greater than 100 beats per minute), and rhythms that may be present when there is no pulse (in cardiac arrest) including ventricular fibrillation, ventricular tachycardia, pulseless electrical activity, and asystole (described later in this chapter). (cont.) 20

Mechanical Malfunctions of the Heart
Causes of Cardiac Compromise Mechanical Malfunctions of the Heart This can lead to cardiac arrest, shock, pulmonary edema (fluids “backing up” in the lungs), or congestive heart failure. Another complication sometimes seen with a myocardial infarction, or heart attack, is mechanical pump failure. A lack of oxygen has caused the death of a portion of the myocardium. The dead area can no longer contract and pump. If a large enough area of the heart dies, the pumping action of the whole heart will be affected. This can lead to cardiac arrest, shock, pulmonary edema (fluids “backing up” in the lungs), or congestive heart failure (discussed later in this chapter). A few heart attack patients suffer cardiac rupture as the dead tissue area of the heart muscle bursts open. This occurs days after a heart attack. Deterioration or malfunction of the valves of the heart is also a common component of cardiovascular disorders such as congestive heart failure. (cont.) 21

Angina Pectoris Coronary arteries Partial blockage producing chest pain Angina pectoris means, literally, a pain in the chest. Coronary artery disease has narrowed the arteries that supply the heart. During times of exertion or stress, the heart works harder. The portion of the myocardium supplied by the narrowed artery becomes starved for oxygen. When the myocardium is deprived of oxygen, chest pain—angina pectoris—is the most frequent result. This pain is sometimes called an angina attack. Since the pain of angina pectoris comes on after stress or exertion, the pain will frequently diminish when the patient stops the exertion. As the oxygen demand of the heart returns to normal, the pain subsides. Seldom does this painful attack last longer than 3 to 5 minutes. Area of decreased blood supply (cont.) 22

Click here to view an animation on angina pectoris.
Causes of Cardiac Compromise Angina Pectoris Click here to view an animation on angina pectoris. (cont.) 23

Acute Myocardial Infarction The condition in which a portion of the myocardium (heart muscle) dies as a result of oxygen starvation is known as acute myocardial infarction (AMI). Often called a heart attack by lay persons, AMI is brought on by the narrowing or occlusion of the coronary artery that supplies the region with blood. Rarely, the interruption of blood flow to the myocardium may be due to the rupturing of a coronary artery (aneurysm). A variety of factors can cause an AMI. Coronary artery disease is usually the underlying reason for the incident. However, for some patients, factors often regarded as harmless may trigger an AMI. These factors include chronic respiratory problems, unusual exertion, or severe emotional stress. Area of Infarct (cont.) 24

Myocardial infarction or ventricular weakening causes blood back-up to the lungs with fluid accumulation. (cont.) 25

Congestive Heart Failure
Causes of Cardiac Compromise Congestive Heart Failure The signs and symptoms of heart failure will be dependent on the severity of the condition and whether it is an acute-onset or a long-term problem. They include the following: • Marked or severe dyspnea (shortness of breath) • Tachycardia (rapid heart rate greater than 100 bpm) • Difficulty breathing when supine (orthopnea) • Suddenly waking at night with dyspnea (paroxysmal nocturnal dyspnea) • Fatigue on any type of exertion • Anxiety • Tachypnea (rapid respiratory rate) • Diaphoresis (sweating) • Upright position with legs, feet, arms, and hands dangling • Cool, clammy, pale skin • Chest discomfort • Cyanosis • Agitation and restlessness due to the hypoxia • Edema (swelling) to the ankles, feet, and hands • Crackles and possibly wheezes on auscultation • Decreased SpO2 reading • Signs and symptoms of pulmonary edema • Blood pressure may be normal, elevated, or low • Distended neck veins—jugular venous distension (JVD) (late) • Distended and soft, spongy abdomen 26

Symptoms of Cardiac Compromise
Chest Pain Discomfort in chest or upper abdomen Pain, pressure, crushing, squeezing, heaviness Palpitation/fluttering May radiate down one or both arms The following list of symptoms is common for females suffering from an ischemia or infarction. Although you’ll see that some descriptions are the same as males, many others are not: “Classical” findings (not necessarily common findings) • Dull, substernal chest pain or discomfort • Respiratory distress • Nausea, vomiting • Diaphoresis “Non-classical” or “atypical” findings (not necessarily uncommon findings) Neck ache Pressure in the chest Pains in the back or breast Tingling of the fingers Unexplained fatigue or weight gain (water weight gain) Insomnia Since the death rate for females who suffer heart attacks are higher than males when the event occurs, the EMT should have a high index of suspicion of ACS when gathering a history from the female patient. Err on the side of the patient and provide emergency care for a potential myocardial infarction or ACS, despite a presentation of “atypical” signs of ischemia or infarction. 27

Signs and Symptoms of Cardiac Compromise
Difficulty breathing (dyspnea) Nausea, vomiting Anxiety/feeling of impending doom The elderly, diabetics, and female patients may not experience chest pain or discomfort in cardiac compromise. Weakness and difficulty breathing are more common symptoms. Signs and symptoms associated with cardiac compromise or acute coronary syndrome may vary widely, depending on the patient’s individual response. Despite the many variables, the most common signs and symptoms of acute coronary syndromes are these: • Chest discomfort or pain that radiates to any of the following areas: chest, neck, jaw, arm, or back; also epigastric (upper abdomen) pain that may be described as indigestion • Sudden onset of sweating (This may be a significant finding by itself.) • Cool, pale skin • Difficulty in breathing (dyspnea) • Light-headedness or dizziness (vertigo) • Anxiety or irritability • Feelings of impending doom • Abnormal or irregular heart rate • Abnormal blood pressure • Nausea and/or vomiting (cont.) 28

Signs and Symptoms of Cardiac Compromise
Cool, pale skin Dizziness Sweating Abnormal heart rates Tachycardia—faster than 100 bpm Bradycardia—slower than 60 bpm Abnormal blood pressures Signs and symptoms associated with cardiac compromise or acute coronary syndrome may vary widely, depending on the patient’s individual response. Despite the many variables, the most common signs and symptoms of acute coronary syndromes are these: • Chest discomfort or pain that radiates to any of the following areas: chest, neck, jaw, arm, or back; also epigastric (upper abdomen) pain that may be described as indigestion • Sudden onset of sweating (This may be a significant finding by itself.) • Cool, pale skin • Difficulty in breathing (dyspnea) • Light-headedness or dizziness (vertigo) • Anxiety or irritability • Feelings of impending doom • Abnormal or irregular heart rate • Abnormal blood pressure • Nausea and/or vomiting 29

Perform a Complete Initial Assessment
The following slides represent the steps if the initial assessment allows a systematic approach to assessment for, and control of, life threats. It is vital that you progress through the steps in this exact sequence, and do not allow dramatic but non-life-threatening injuries or conditions to cloud your priorities. 30

Place Patient in Position of Comfort; Give High-Concentration Oxygen by Nonrebreather Mask
Place the patient in a position of comfort, typically sitting up; this is especially true of patients with difficulty breathing. Patients who are hypotensive (systolic blood pressure less than 90) will usually feel better lying down. This position allows more blood to flow to the brain. Occasionally, you will see a patient who has both difficulty breathing and hypotension. It may be very difficult to find a good position in this case. The best way to determine the proper position is to ask the patient what position will relieve his breathing difficulty without making him weak or lightheaded. 31

Perform Focused History and Physical Exam; Take Baseline Vital Signs
After performing your initial assessment, perform a focused history and physical exam. Get a history of the present illness by asking the OPQRST questions (inquire about onset, provocation, quality, radiation, severity, and time). Also get a SAMPLE history (signs/symptoms, allergies, medications the patient may be taking, pertinent past history, last oral intake, events leading to the present emergency). Then take baseline vital signs. 32

Assessing Cardiac Compromise
Transport immediately if: No history of cardiac problems OR History of cardiac problems, but no nitroglycerin OR Systolic blood pressure is <100 Transport immediately if the patient has any one of the following: • No history of cardiac problems • History of cardiac problems, but does not have nitroglycerin • Systolic blood pressure below 100 (cont.) 33

Assessing Cardiac Compromise
Transport decision: If available, transport patient to hospitals that have: “Clot-buster” capabilities Ability to perform angioplasty Local protocols will provide guidance. Determine where you will transport the patient. In areas with more than one hospital, there may be one or two facilities with special treatment available for cardiac patients. Almost all hospitals can administer an intravenous drug to dissolve the clot that is causing insufficient oxygenation of the heart. Another way to unclog the coronary artery is to insert a catheter with a balloon at the tip into the arterial system and thread it into the coronary arteries. When the balloon reaches the narrow section of artery, it is inflated, compressing the obstructive material against the side of the blood vessel and opening up circulation to the heart muscle again. This method is often better than the “clot-buster drug” approach when it is done early (within a few hours of onset of symptoms). Only hospitals with special facilities and available staff can do this, however. If your EMS system has the ability to transport to a hospital with this capability, there will be a local protocol that you should follow describing when, where, and how you should transport patients with certain signs and symptoms. 34

Nitroglycerin While patients with known cardiac problems may be on a variety of medications, the most common will be nitroglycerin. Nitroglycerin is a potent vasodilator (agent that increases the diameter of blood vessels). It works in seconds to relax the muscles of the blood vessel walls. This action dilates arteries, increasing the blood flow through the coronary arteries and oxygen supply to the heart muscle and decreasing the work load of the heart. Nitroglycerin can be either a sublingual (under-the-tongue) tablet or a sublingual spray. A paste form of nitroglycerin is also available, but it is not considered appropriate for administration by an EMT, since the onset of action is too long. If the patient with a history of heart problems is suffering from cardiac-related chest pain and has nitroglycerin that has been prescribed for him by a physician, you may assist the patient in taking this medication after receiving authorization from medical direction. 35

To Administer Nitroglycerin
Patients must have: Chest pain History of cardiac problems Prescribed nitroglycerin with them BP meets or exceeds local protocol requirements (often 100 mmHg or greater) Not recently taken Viagra or similar drug for erectile dysfunction Medical direction authorizes administration. Another indication that the patient has a history of this condition is if the patient has the medication nitroglycerin. Nitroglycerin is a medication that dilates the blood vessels. This results in more blood staying in the veins of the body, so there is less blood coming back to the heart. With less blood to pump out, the heart does not have to work as hard. Nitroglycerin is available in tablets that are placed under the patient’s tongue to dissolve, and also in sprays and patches. The patches have adhesive that keeps them on the skin. They gradually release nitroglycerin throughout the day. Most angina patients are advised by their doctors to take nitroglycerin for their chest pain. Patients are usually told to rest and are allowed to take three nitroglycerin doses over a 10-minute period. If there is no relief of symptoms after that time, they are instructed to call for help. 36

The Five Rights Five “Rights” Right patient? Right medication?
Right dose? Right route? Right date ? 37

Nitroglycerin Administration
If patient meets nitroglycerin criteria, consult medical direction. Check the medication to ensure that it is prescribed for the patient, it is the proper medication, and it has not expired. Remove oxygen mask and ask patient to open mouth and lift tongue. Place nitroglycerin under the tongue (either spray or pill). Place nitroglycerin under the tongue (either spray or pill). Be sure to assess patient’s blood pressure prior to assisting with nitroglycerin. Have patient close mouth. Replace oxygen mask. Reassess vital signs after administration and document findings. 38

Repeat Nitroglycerin if:
Patient gets no or only partial relief AND Blood pressure remains acceptable per protocol Medical direction authorizes another dose Maximum three doses After giving one dose of the nitroglycerin, give a repeat dose in 5 minutes if all of the following conditions are met: • Patient experiences no relief or only partial relief • Systolic blood pressure remains greater than 100 systolic • Medical direction authorizes another dose of the medication Administer a maximum of three doses of nitroglycerin, reassessing vital signs and chest pain after each dose. If the blood pressure falls below 90–100 systolic, treat the patient for shock (hypoperfusion). Transport promptly. 39

Administration of Aspirin (if Local Protocols Allow)
Patient must have: Chest pain No allergies to aspirin No history of asthma Not taken any other clotting medications Ability to swallow Medical direction authorizes administration. 40

Cardiac Compromise and BLS
41

Click here to view an animation on cardiac compromise.
Angina pectoris means, literally, a pain in the chest. Coronary artery disease has narrowed the arteries that supply the heart. During times of exertion or stress, the heart works harder. The portion of the myocardium supplied by the narrowed artery becomes starved for oxygen. When the myocardium is deprived of oxygen, chest pain—angina pectoris—is the most frequent result. This pain is sometimes called an angina attack. Since the pain of angina pectoris comes on after stress or exertion, the pain will frequently diminish when the patient stops the exertion. As the oxygen demand of the heart returns to normal, the pain subsides. Seldom does this painful attack last longer than 3 to 5 minutes. Click here to view an animation on cardiac compromise. (cont.) 42

Cardiac Compromise Some patients with cardiac compromise go into cardiac arrest. You must be prepared for that, but fortunately, most patients with heart problems do not go into cardiac arrest. In a typical ambulance service, only 1 to 2 percent of emergency calls are cardiac arrests. Most patients with heart problems do not go into cardiac arrest while they are under your care. Nonetheless, EMS systems exert a great deal of time and energy on attempts to resuscitate these patients. The odds of bringing a cardiac-arrest patient back to life have increased considerably over the last 15 or 20 years. As the problem of cardiac arrest has received more attention, EMS researchers, physicians, administrators, and providers have learned more about what is effective and what is not. 43

American Heart Association “Chain of Survival”
The American Heart Association has summarized the most important factors that affect survival of cardiac arrest patients in its chain of survival concept. The chain has four elements: (1) early access, (2) early CPR, (3) early defibrillation, and (4) early advanced care. An EMS system where each of these links is strong is much more likely to bring back a patient from cardiac arrest than a system with weaknesses anywhere along the chain. This has been shown in systems that tried to strengthen just one link (early defibrillation) without strengthening the other links. 44

Early Access Public recognizes an emergency exists.
Public knows emergency access phone number (911 or other #). Early access means that the person who sees someone collapse or finds someone unresponsive calls a dispatcher who quickly gets EMS responding to the emergency. Unfortunately, this is easier said than done. The lay public, unlike EMS providers, are not used to recognizing emergencies. It takes longer for them to realize that an emergency exists and that they should call for help right away. Even when a lay person does decide to make the call for help, there may still be obstacles. 45

Early CPR Train the public to perform CPR.
Get CPR-trained professionals to the patient faster. Train dispatchers to instruct callers in CPR. Early CPR can increase survival significantly. About the only time it does not help is when defibrillation reaches the patient within approximately 2 minutes or less. Since this is rarely the case in real life, this means EMS agencies need to address this factor. There are at least three ways in which CPR can be delivered earlier: get CPR-trained professionals to the patient faster, train lay people in CPR, and train dispatchers to instruct callers in how to perform CPR. An efficient way to get CPR to patients faster in many areas is to send CPR-trained professionals to the scene. This may mean police, fire fighters, security officers, or lifeguards. Whoever it is, needs to receive notification of the possible need for CPR as soon as possible. They also need to be in the right place in order to be able to respond quickly to where they are needed. 46

Early Defibrillation Single most important factor in survivability (time is critical!) Automated External Defibrillation (AED) Use of nontraditional responders (police, fire, security, for example) Early defibrillation has received a great deal of attention because it is the single most important factor in determining survival from cardiac arrest. Although a lot of emphasis has been put on defibrillation, frequently there has not been enough attention paid to early defibrillation. With a few thousand dollars or less, an agency can purchase an automated defibrillator. The hard part is getting it to the patient in cardiac arrest early enough to be effective. If the response time of the defibrillator (time from call received to arrival of the defibrillator) is longer than 8 minutes, virtually no one survives cardiac arrest. This is true even with early CPR. Although 8 minutes is really the maximum response time for effective defibrillation, the sooner the defibrillator arrives, the more likely it is that a patient will survive cardiac arrest. This is one time when it is literally true that every minute counts. 47

Early Advanced Care Advanced Cardiac Life Support (ACLS)
Typically provided by EMT-Paramedics (other EMT levels may have some options) Also provided by emergency department physicians Early advanced care is second only to defibrillation in the drama and excitement it stirs in lay people. Putting a breathing tube into someone’s throat (endotracheal intubation), putting a needle into someone’s arm (starting an intravenous line), and administering medications into an IV line are all activities that lay people may not understand, but they are actions that the public has come to expect. They may also lead to a higher survival rate. The most common way for patients to get advanced cardiac life support (ACLS) is through EMT-Paramedics who either respond to the scene or rendezvous with a basic life support unit en route to the hospital. 48

Management of Cardiac Arrest
You must be able to: Use an automated external defibrillator. Request ALS backup when appropriate. Use BVM and FROPVD. Lift and move patients. (cont.) 49

Management Cardiac Arrest
You must also be able to: Suction the airway. Use airway adjuncts. Take Standard Precautions. Interview family/bystanders. 50

Automated External Defibrillation
51

Automated External Defibrillation
Many EMS systems have resuscitated patients with AEDs (automated external defibrillators). The highest survival rates occur in systems with strong links in the chain of survival. If defibrillation cannot be provided within 4 to 5 minutes of collapse, then the providers should give 5 cycles of 30:2 compression/ventilations (about 2 minutes worth of CPR) prior to defibrillating. This is to provide oxygenated blood, glucose, and other metabolic substrates to the myocardium so that conversion from ventricular fibrillation to a perfusing rhythm is more likely with the defibrillation. If the arrest was witnessed or the known “down time” has been less than 4 minutes, the provider should first apply the AED, follow the AED sequence, defibrillate if advised, and then initiate or resume CPR. 52

Types of AEDs Semi-automatic/shock advisory Fully automatic
Computer in AED analyzes rhythm and advises EMT to deliver shock. Fully automatic EMT turns on power and attaches to patient; shocks delivered automatically if needed. There are two types of automated external defibrillators: semiautomatic and fully automatic. Semiautomatic defibrillators, the more common type, advise the EMT to press a button that will cause the machine to deliver a shock through the pads. Semiautomatic defibrillators are sometimes called “shock advisory defibrillators.” Fully automated defibrillators do not advise the EMT to take any action. They deliver the shock automatically once enough energy has been accumulated. All the EMT has to do to use a fully automatic defibrillator is assess the patient, turn on the power, and put the pads on the patient’s chest. (cont.) 53

Types of AEDs Monophasic: Biphasic:
Sends single shock (energy current) from one pad to the other Biphasic: Sends shock in both directions, measures resistance, and adjusts energy Causes less damage to heart muscle Another way in which AEDs can be classified is by the type of shock they deliver. The traditional monophasic defibrillator sends a single shock (this is what monophasic means) from the negative pad or paddle to the positive pad or paddle. A biphasic defibrillator sends the shock in one direction and then the other. This kind of machine also typically measures the impedance or resistance between the two pads and adjusts the energy accordingly, delivering more energy when the impedance is higher and less when it is lower. These features allow biphasic AEDs to use less energy and perhaps cause less damage to the heart. Use of biphasic AEDs does not result in higher survival rates, but they are at least as good as monophasic machines and have other advantages. Because the battery doesn’t need to deliver as much energy, it is smaller and lighter than monophasic AEDs, a significant factor when an EMT has to carry several heavy pieces of equipment at once. 54

Analysis of Cardiac Rhythm
AEDs are extremely accurate in distinguishing between shockable and nonshockable rhythms. Like all muscles, the heart produces electrical impulses. By putting two monitoring electrodes on the chest, it is possible to “see” the electrical activity of the heart. An AED can analyze this cardiac rhythm and determine whether or not it is a rhythm for which a shock is indicated. The microprocessors and the computer programs used to do this have been tested extensively and have been very accurate, both in the laboratory and in the field. Today’s AEDs are very reliable in distinguishing between rhythms that need shocks and rhythms that do not need shocks. 55

Inappropriate Shock Very rarely does the AED computer make a mistake.
AED-related errors are almost always human error due to: Touching the patient during analysis. Not stopping the ambulance to analyze rhythm. When AEDs deliver shocks inappropriately, it is almost always the result of human error. This occurs because the operator did not assess the patient properly (AEDs are designed only for use on patients in cardiac arrest), did not use the AED properly, or did not maintain the machine. The chance of mechanical error is always present, but it is small. Maintaining the AED in good operating order; attaching an AED only to unresponsive, pulseless, nonbreathing patients; practicing frequently; and following your local protocols are the best ways to avoid making an error that could affect a patient. 56

AEDs will shock two rhythms:
Shockable Rhythm AEDs will shock two rhythms: Ventricular fibrillation Up to 50% of cardiac arrest patients Ventricular tachycardia over certain rates Up to 10% of cardiac arrest patients The most common conditions that result in cardiac arrest are shockable rhythms: • Ventricular fibrillation • Ventricular tachycardia (If the rate is greater than 180 bpm, it is possible that the patient may not have a pulse.) The primary electrical disturbance resulting in cardiac arrest is ventricular fibrillation (VF). Up to 50 percent of all cardiac arrest victims will be in VF if EMS personnel arrive in the first 8 minutes or so. The heart in VF may have plenty of electrical energy, but it is totally disorganized. Chaotic electrical activity originating from many sites in the heart prevents the heart muscle from contracting normally and pumping blood. If you could see a heart in VF, it would appear to be quivering like a bag of worms. VF is considered a “shockable rhythm;” that is, VF is a rhythm for which defibrillation is effective. 57

Non-shockable Rhythm An AED will not shock:
Asystole (20–50% of victims) OR Pulseless electrical activity (PEA) (15–20% of victims) Typically, at most 6 to 7 out of 10 patients are in a shockable rhythm. Nonshockable rhythms include: • Pulseless electrical activity (PEA) • Asystole In 15 to 20 percent of cardiac arrest victims, the rhythm is called pulseless electrical activity (PEA); that is, the heart muscle itself fails even though the electrical rhythm remains relatively normal. This condition of relatively normal electrical activity but no pumping action means that the heart muscle is severely and almost always terminally sick. In the remaining 20 to 50 percent of cardiac arrest victims, the heart has ceased generating electrical impulses altogether. This is a condition called asystole. When this happens, there is no electrical stimulus to cause the heart muscle to contract, and so it does not. As a result, there is no blood flow, and the patient has no pulse or respirations and is unconscious. (This condition is commonly called “flatline,” because the wavy line displayed on an ECG when there is electrical activity goes flat with asystole.) 58

Safety Considerations
An AED must be applied ONLY to a patient who is unresponsive, apneic, and pulseless. The AED was initially developed and primarily used on adult patients in nontraumatic cardiac arrest. However, current research has shown that it can be used with younger age groups. The AED is not intended for trauma patients. When you encounter an unresponsive patient with no respiration and no pulse, act immediately. (cont.) 59

Safety Considerations
No one should do CPR or touch the patient when the AED is analyzing the rhythm or delivering a shock. 60

Shock First or Compressions
When the response time is greater than 4 to 5 minutes, it is appropriate to do 2 minutes of CPR (about 5 cycles) prior to analyzing and administering the first shock. It is appropriate to “re-prime the pump” by doing CPR for 2 minutes. If you come on the scene and a citizen or other provider is already doing high-quality compressions, you can count that effort toward the first 2 minutes and proceed with applying the AED. 61

Note Do not delay defibrillation to perform CPR.
Defibrillation is the priority! During your course in cardiopulmonary resuscitation, you learned to interrupt CPR only when absolutely necessary and for as short a period as possible. Since you will be using a defibrillator on patients in cardiac arrest, you need to understand some additional circumstances when you should interrupt CPR. 62

Take Standard Precautions
Take Standard Precautions. Briefly question bystanders about pre-arrest events. As with all calls, you should protect yourself from infectious diseases by using personal protective equipment and taking Standard Precautions. This is especially important in the case of a cardiac arrest where blood and other body fluids are commonly found. 63

Perform Initial Assessment; Verify Patient Is Pulseless and Not Breathing
Perform the initial assessment. If a bystander is doing CPR when you arrive, have the bystander stop. Verify pulselessness (no carotid pulse) and apnea (no breathing) for no longer than 10 seconds. Look for external blood loss. Resume CPR immediately and perform a focused history and physical exam. Inquire about onset, trauma, and signs and symptoms that were present before the patient collapsed. Get a SAMPLE history if you can. Do not let history gathering interfere with or slow down defibrillation. 64

AED Contraindications
Is the patient younger than 1 year old? Is there any trauma? If “yes” to either, do not use the AED. 65

Set Up AED as Partner Starts (or Resumes) CPR
66

Turn on Power and, if Appropriate, Begin Verbal Report
67

Firmly Attach One Pad to Right-Upper Bare Chest; Firmly Place One Pad over Lower-Left Bare Ribs
68

Proper Placement of AED Pads
If the pads are less than one inch apart, you may place one pad on the anterior (chest) and the other on the posterior (back). 69

Say “Clear!”; Ensure No One Is Touching Patient; Press Analyze Button
70

If AED Advises Shock, Say “Clear”; Ensure No One Is Touching Patient; Press Shock Button
71

If There Is No Pulse, Resume CPR for Two Minutes; Check Effectiveness of CPR by Evaluating Pulse
72

Insert an Airway Adjunct, and Ventilate with High-Concentration Oxygen
73

After Two Minutes of CPR, Clear Patient and Repeat Sequence
74

If No Shock Is Advised, Check Carotid Pulse; If Present, Assess Adequacy of Breathing
75

If Breathing Is Adequate, Give High-Concentration Oxygen by Nonrebreather
If inadequate, ventilate with high-concentration oxygen. 76

General AED Procedures
While one EMT operates the AED, the partner performs CPR. Defibrillation is first priority! Remember that CPR must include high-quality compressions. Defibrillation comes first. Do not hook up oxygen or do anything that delays analysis of the rhythm or defibrillation. You must be familiar with the particular model of AED used in your area. (cont.) 77

Do not touch patient when analyzing rhythm and delivering shocks. Do not analyze rhythm or defibrillate in a moving ambulance. Stop first. All contact with the patient must be avoided during analysis of the rhythm. State “Clear!” and be sure everyone is clear of the patient before delivering every shock. Emphasize that while it may be necessary to stop the ambulance to adequately analyze a rhythm, it is vital to not delay transport any longer than absolutely necessary. (cont.) 78

Be familiar with your model of AED. Check batteries at beginning of shift. Follow manufacturer’s charging recommendations. Carry an extra battery. No defibrillator is capable of working without properly functioning batteries. Check the batteries at the beginning of your shift and carry an extra. Also, AED pads should be in good condition, unopened, and within expiration dates. 79

Coordination of EMT and ALS
Call for ALS as soon as possible. Local protocols determine if you should wait for ALS or begin transport to rendezvous with ALS. You do not need to have an advanced life support (ALS) team at the scene in order to use an AED, but the sooner the patient receives advanced cardiac life support (ACLS), the greater the patient’s chance of survival. If you have an ALS team available, notify them of the arrest as soon as possible (preferably before you even arrive on scene). Whether you postpone transport and wait for the ALS team at the scene or start transport and rendezvous with them should be in local protocols approved by your medical director. Your actions may depend on the location of the arrest and the estimated time of arrival of the ALS team. 80

AED in Progress If AED is in use by a first responder when you arrive, ensure that the AED is being used properly, and continue with shocks. First Responders, police officers, security officers, and others may defibrillate the patient before you arrive. If this happens, you should let the operator of the AED complete the shock before you take over care of the patient. After the shock is delivered, or a “No shock” message is received, work with the operator to bring about an orderly transfer of care. In some areas, you may need to take the first AED to the hospital with the patient so that data can be retrieved from the machine. Your protocols should address this. They also should tell you whether or not to switch from the first AED to your own. 81

Post-resuscitation Care
Maintain airway. Transfer to ambulance. Coordinate rendezvous with ALS if appropriate. After you have run through the automated external defibrillation protocol, the patient will be in one of three conditions: (1) The patient has a pulse. In this case, you will need to keep a close eye on his airway and be aggressive in keeping it open. Keep the defibrillator on the patient during transportation in case the patient goes back into arrest. En route, perform a focused assessment based on what the patient tells you is bothering him, and perform an ongoing assessment every 5 minutes. (2) If the patient has no pulse, the AED will have given you a “No shock indicated” message, or (3) the AED may be prompting you to analyze the rhythm because it “thinks” there is a shockable rhythm. In either case, you will need to resume CPR. (You will not perform further defibrillation once you have completed the initial shocks of the AED protocol unless the patient has recovered a pulse and then, later, goes back into cardiac arrest.) (cont.) 82

Leave AED attached to patient. Patient has a high risk of returning to cardiac arrest. Perform focused assessment and ongoing assessment en route. (cont.) 83

If patient is unconscious, check pulse at least every 30 seconds. If no pulse: Stop ambulance. Analyze rhythm/deliver shocks per local protocol. If AED not available, perform CPR. A patient who has been resuscitated from cardiac arrest is at high risk of going back into arrest. This change may be difficult to detect since most patients who have just been resuscitated are unconscious and many of them will need assisted ventilation. Since you are breathing for the patient, you may not notice that he no longer has a pulse. This is why, on unconscious patients who have recovered a pulse, you should check the pulse frequently (approximately every 30 seconds). The AED may alert you that it “thinks” the patient has a shockable rhythm. If you get such a prompt from the defibrillator, check for a pulse immediately. 84

Single Rescuer with AED
If the downtime was prolonged, perform 2 minutes of CPR If the patient was a witnessed arrest immediately defibrillate. Some EMTs will be alone or have no one else nearby who can do CPR when they reach the patient. If this happens, the sequence of steps to take changes slightly. If the patient was a witnessed arrest, defibrillate immediately. If the downtime was prolonged, perform 2 minutes (5 cycles) of CPR. 85

Pediatrics and AED Do not use on patients less than 1 year old.
Aggressive airway management and CPR are best methods. AED may be beneficial if pediatric AED is available. Unlike adults, infants have healthy hearts and go into shockable rhythms less often. Cardiac arrest in infants is more often caused by respiratory problems like foreign body airway obstruction or drowning. For this reason, aggressive airway management and artificial ventilation with chest compressions are the best way to resuscitate these patients. Applying a defibrillator to an infant would not help the patient and would result in delays to definitive in-hospital care. AEDs are now on the market that can be adapted to pediatric use in children over 1 year of age through reducing the energy delivered and attaching smaller pads designed for children’s chests (smaller pads and smaller shocks). If your service has such an AED, you should follow the protocol for its use. 86

Additional Safety Considerations
Water Dry patient’s chest; remove from wet environment. Metal Ensure no one is touching any metal that the patient is in contact with. Do not defibrillate a soaking-wet patient. Water is a very good conductor of electricity, so either dry the patient’s chest or move him out of the wet environment (bring him inside, away from the rain, for example). Do not defibrillate the patient if he is touching anything metallic that other people are touching. Metal is also a very good conductor of electricity. This means that you must be careful if the patient is on a metal floor or deck, and you must make sure no one is touching the stretcher when you deliver a shock. It is a good idea to make sure no one is touching anything, including a bag-valve mask, that is in contact with the patient. (cont.) 87

Additional Safety Considerations
Medication patch If patch is visible on chest, remove it with gloved hands before delivering shock. If you see a nitroglycerin patch on the patient’s chest, remove it carefully before defibrillating. The plastic in the patch (not the nitroglycerin) may explode from the rapid melting that a defibrillatory shock can cause. This problem has been reported only when the patch is on the chest. Be sure to wear gloves when you remove the patch. It is designed to release nitroglycerin through the skin, and it will not discriminate between the patient’s skin and yours. One thing you don't need at a cardiac arrest is a headache from nitroglycerin. 88

Advantages of AEDs Initial training and continuing education are simple. AEDs are very fast. Until 25 years ago, it was unthinkable for EMTs to defibrillate patients in cardiac arrest. Now, EMTs are expected to be trained and equipped to perform this potentially life-saving intervention. The biggest reason this situation has changed is the improvement in technology that allows defibrillators to determine whether a patient’s rhythm is shockable quickly and accurately. (cont.) 89

Advantages of AEDs Use of adhesive pads instead of paddles is safer, provides better electrode placement, and lowers EMT’s anxiety. Automation also requires that the operator defibrillate through adhesive pads instead of paddles. This is safer and allows for more accurate and consistent electrode placement. Since the operator does not have to hold paddles on the patient’s chest, there is almost no chance of “arcing,” the passage of electrical current outside the chest from too little paddle pressure. Certainly, the level of anxiety of the EMT is lower when he can push a button to deliver a shock instead of holding charged paddles on a patient’s chest. 90

AED Maintenance AED failure typically results from inadequate maintenance. Failing to check and maintain AED Use daily checklist to maintain machine and supplies. After the U.S. Food and Drug Administration received a number of reports of AED failures some years ago, the agency convened a panel of experts to review reports of these malfunctions. The experts drafted a checklist of actions that the defibrillator operator should complete on each shift. One of the most common problems with AEDs has been battery failure. It is especially important that you make sure the battery is charged and that you have a spare with the defibrillator. A defibrillator with a dead battery helps no one. You should use the checklist at the beginning of every shift in order to be sure that you have all the supplies you will need and that the AED is functioning properly. The time to discover a problem is before you need the defibrillator, not when you are at the scene of a cardiac arrest. 91

AED Quality Improvement
Medical direction Review calls. Assist in training and skills. Continuing education Skill review every three months Data collection There are many ways you can evaluate and improve your ability to resuscitate patients in cardiac arrest. These methods should be part of your service’s quality improvement (QI) program. The defibrillation part of your QI program involves a number of things, including medical direction, initial training, maintenance of skills, case review, trend analysis, and strengthening the links in the chain of survival. Every participant in the EMS system has a role to play in QI, whether it is the patient who comes back to thank you, the physician who praises you for a job well done, the nurse who follows up on the patient’s in-hospital course, or the EMT who uses the defibrillator and then documents the call. 92

Review Questions What position is best for a patient with:
Difficulty breathing and a blood pressure of 100/70? Chest pain and a blood pressure of 180/90? What is the best way to transfer a patient with difficulty breathing, chest pressure, and a blood pressure of 160/100 down a flight of stairs? There are a variety of game show templates that instructors may use to enhance the learning process. These can be a fun way to evaluate student comprehension and, depending upon how you conduct the game, build teamwork among the students. The following link is a collection of templates like Jeopardy, Who Wants to be a Millionaire, etc. There are a variety of sites that contain predesigned templates that may be found during a web search. (cont.) 93

Review Questions Describe how to “clear” a patient before administering a shock. List three safety measures to keep in mind when using an AED. List the steps in the application of an AED. 94

Street Scenes What type of emergency equipment needs to be taken to the side of every potential cardiac patient? What are the treatment priorities for this patient? (cont.) 95

Street Scenes What assessment information do you need to obtain next?
What should you do next? 96

Sample Documentation 97

Chapter 17 Cardiac Emergencies

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