Cardiac Emergencies. A Review of Cardiac Compromise. Lawrence L. Lambert

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1 Cardiac Emergencies A Review of Cardiac Compromise Lawrence L. Lambert 1

2 Cardiac Emergencies Objectives: Following successful completion of this training session, the student should be able to: 1. Describe the structure and function of the cardiovascular system. 2. Describe the signs and symptoms of a patient experiencing angina, myocardial infarction, congestive heart failure, and cardiogenic shock. 3. List the indication and dosage for nitroglycerin. 4. Demonstrate the proper assessment and management various cardiac patients. To receive credit for this training, the member must complete the attached module. 2

3 Circulatory System Anatomy and Physiology The Heart The heart is a four-chambered pump about the size of an adult fist. Made up of a specialized muscle mass (commonly referred to as the myocardium which is actually the thick middle layer of the heart wall), the heart is functionally divided into the right and left sides. The right side receives deoxygenated blood (via the superior and inferior vena cava) returning from the body and pumps it to the lungs (via the right and left pulmonary arteries). The left side of the heart receives oxygenated blood from the lungs (via the pulmonary veins) and pumps it to the body s cells through arteries. The top two chambers are called the atria. The bottom two chambers are called the ventricles. Since the left side of the heart pumps blood throughout the entire body, the left ventricle has the largest muscle mass and is a common site of injury or infarct. There are four valves located within the heart s chambers: tricuspid (between the right atrium and ventricle); pulmonary (at the base of the pulmonary artery); mitral or bicuspid (between the left atrium and ventricle); and the aortic valve (at the base of the aorta). These valves prevent back low of blood in the system. The heart is more than just a muscle. It also contains specialized contractile and conductive tissue, knows as the cardiac conduction system, that allows it to generate electrical impulses. These impulses allow the heart to contract or beat differently than other muscles. The electrical impulse is generated at the sinoatrial node (SA node) in the right atrium. It travels through atria, causing both to contract simultaneously, propelling blood to the ventricles. Next the impulse travels to the atrioventricular node (AV node) which is the area between the atria and ventricles. The Bundle of His then carries the impulse into the right and left ventricles to the Purkinje fibers, causing the ventricles to contract simultaneously and pump the blood through the lungs and throughout the body. The Blood Vessels Arteries always carry blood away from the heart. Arterioles are the smallest branches of the arteries and carry blood from the arteries to the capillary beds. Capillaries are a network of tiny blood vessels connecting arterioles to venules. Found in all parts of the body, the capillary network ensures that all body cells are nourished and their wastes removed. The walls of capillaries are only one-cell thick, which allows oxygen and nutrients to pass from the blood into the cells and allows carbon dioxide and other wastes to pass from the cells into the blood and ultimately out of the body. Venules are the smallest branches of the veins and connect the capillaries to the veins. Veins always carry blood back to the heart. The heart is richly supplied with blood vessels, which transport nutrients and oxygen to the cardiac muscle and conduction system. These vessels are referred to as the coronary arteries and originate in the aorta just above the aortic valve. Blockage of these arteries can result in pain, ischemia or infarction (death) of the underlying heart muscle. 3

4 The Blood The average adult has approximately 5 liters of total blood volume. The components of blood include: Red blood cells - gives blood its red color, carries oxygen to the body and carries carbon dioxide away from the body cells White blood cells - part of the body s immune system Plasma - the fluid that carries nutrients and all other components of blood throughout the body Platelets - essential to the formation of blood clots Angina Pectoris Specific Cardiac Emergencies Angina is a condition that occurs when the oxygen demands of the heart are transiently exceeded by the blood supply. Reduction of blood flow can result from several conditions (such as spasm of the coronary artery); most commonly, however, blockage is a result of atherosclerosis. Angina is divided into two types stable and unstable angina. Stable angina occurs during activity, when the oxygen demands of the heart are increased. Usually precipitated by exercise or stress, stable angina usually lasts no longer than minutes. The pain of stable angina is often relieved by rest, nitroglycerin or oxygen. On the other hand, unstable angina occurs at rest and may not respond as readily to rest or nitroglycerin. Unstable angina often indicates severe atherosclerosis and is also called preinfarction angina. The pain associated with angina is primarily caused by a buildup of lactic acid and carbon dioxide in the myocardium. The pain may described as crushing, tightness, pressure or indigestion, and is located under the sternum (substernal) or in the epigastric area. Some patients feel pain only in the chest while others have pain that radiates to the shoulder, arm, neck, jaw or through the back. Some patients also experience associated symptoms such as anxiety, dyspnea, nausea, diaphoresis, or weakness. Angina can also be accompanied by dysrhythmias. Often, angina patients are familiar with their condition and may be prescribed nitroglycerin. If possible, the EMT or paramedic should find out if the patient has taken any nitroglycerin, and if so, how much and how long ago was the dosage taken, and if the patient experienced any relief of the discomfort. Management of the patient experiencing angina should be focused on decreasing the myocardial work load and pain relief. If the patient is prescribed nitroglycerin, the EMT-B may assist the patient in administering the nitroglycerin (see attached pharmacology information). 4

5 Myocardial Infarction Acute myocardial infarction (AMI) is the death of a portion of the heart muscle from prolonged oxygen deprivation. Most often associated with atherosclerotic heart disease, the precipitating event can be from the formation of a blood clot in the coronary artery, coronary artery spasm, acute volume overload, hypotension or from acute respiratory failure. Because of the excessive work load of the left ventricle, most infarcts occur in that area. AMI has several complications, the most common of which is dysrhythmias. Life-threatening dysrhythmias can occur almost immediately and can result in sudden death, or death within one hour after the onset of symptoms. In addition, patients can develop congestive heart failure and cardiogenic shock. The most common sign or symptom of AMI is substernal chest pain or epigastric pain. The pain has the same characteristics and location as anginal pain though it is often severe and described as crushing. The pain of an AMI is not usually precipitated by exertion and is not relieved by sublingual nitroglycerin or rest. Some patients experiencing an AMI (especially the elderly) may not have chest pain but may complain of pain in the shoulder, arm, neck, jaw, or back. Other symptoms associated with AMI include anxiety, dyspnea, nausea or vomiting, pallor, general weakness, diaphoresis. The blood pressure can be normal, elevated, or low depending on the extent of infarct. The pulse rate may vary also (fast or slow, regular or irregular, weak or bounding). Dysrhythmias are the most common complication of MI. Therefore, all patients with chest pain should be placed on the monitor and transported for more definitive evaluation and treatment. The prehospital goals of managing an AMI include preventing pain and anxiety, limiting the size of the infarct, preventing serious dysrhythmias and, if a prolonged transport time, initiation of thrombolytic therapy. Congestive Heart Failure Congestive heart failure (CHF) occurs when the heart is still functioning but the myocardium is damaged and can no longer pump adequately to meet the demands of the body. One result of CHF is pulmonary edema. Because the heart cannot keep up with the body s needs, pressure changes occur in the pulmonary capillaries, and fluid passes from the capillaries into the alveoli of the lungs. There is also a build-up of fluid throughout the body, including the neck veins, lower legs, and abdomen. Congestive heart failure can be divided into right and left heart failure. When left ventricular failure occurs, back pressure of blood occurs in the pulmonary circulation. The most common cause of left ventricular failure is a myocardial infarction; therefore, all patients with pulmonary edema should be assumed to have had an MI. When right heart failure occurs, back pressure of blood occurs in the systemic venous circulation resulting in venous congestion. The most common cause of right ventricular failure is left ventricular failure. Signs and symptoms of congestive heart failure include anxiety, dyspnea, rales and/or wheezing, chest pain, rapid pulse, normal or elevated blood pressure, distended neck veins, pedal edema, ascites (edema in the abdomen), cyanosis, desire to sit up, and mild to severe confusion. With these signs and symptoms, the EMT or paramedic must distinguish whether it is an acute or chronic episode. 5

6 Management of CHF should be focused on improving ventilation and oxygenation, decreasing venous return to the heart and decreasing myocardial oxygen demands. Cardiogenic Shock Cardiogenic shock, the most severe form of pump failure, occurs when left ventricular function is so compromised that the heart cannot meet the demands of the body and compensatory mechanisms are exhausted. It usually occurs after extensive myocardial infarction involving more than 40 percent of the left ventricle, or from diffuse ischemia. Signs and symptoms are initially the same as would be expected with an MI. However, as cardiogenic shock develops, hypotension occurs. An altered level of consciousness, pale and cool skin, tachypnea with pulmonary edema, tachycardia, and low blood pressure (often less than 80 mmhg) all point to cardiogenic shock. Management of cardiogenic shock is difficult, even in the hospital. Because the mortality rate is near 90%, prolonged stabilization in the field is not indicated. After completing the primary survey and securing the airway, rapid transport is of utmost importance. The patient should be placed on the EKG monitor, treating any dysrhythmias before focusing on treating hypotension (the dysrhythmias may be the cause of the hypotension). Resources. Prehospital Emergency Care, Sixth Edition, Brady Publishing Paramedic Emergency Care, Third Edition, Brady Publishing Textbook of Advanced Cardiac Life Support, American Heart Association 6

7 Chest Pain Angina AMI Onset Brought on by stress / exertion Sudden onset, even at rest Duration 3-10 minutes >30 minutes Location Under the sternum Under the sternum Radiation Jaw, arms, upper abdomen Jaw, arms, upper abdomen Quality / Intensity Crushing, pressure, tightness, indigestion / mild to moderate, predictable Signs / Symptoms SOB, sweating, nausea, anxiety / apprehension, weakness Squeezing, crushing, heaviness / unpredictable Dyspnea, sweating, fear, feeling of impending doom, irregular pulse, very rapid / slow pulse, weakness, shock Relief With rest, nitroglycerin Not relieved with rest or nitroglycerin 7

8 Cardiac Pharmacology Nitroglycerin Indications: Chest pain Contraindications: Blood pressure <100 systolic Actions: Relaxes coronary arteries Decrease blood return to the heart Side Effects: Dosage: Headache Hypotension 0.4 mg Route: Trade Names: Sublingual (other forms available: topical, IV) NitroDur Nitrolingual Nitro-Bid Nitro-Stat 8

9 Name: Dept. Date: Cardiac Emergencies 1. T / F All patients experiencing a cardiac compromise should receive supplemental oxygen via a nasal cannula at 4 liters per minute. 2. always carry blood to the heart. 3. Transfer of oxygen and nutrients occur in the. 4. The supply the heart muscle with blood and originates at the base of the. 5. List and briefly describe the components of blood. 6. Differentiate the signs and symptoms of angina with those of an acute myocardial infarction. 7. T / F All patients complaining of chest pain shall be assumed to be experiencing angina pectoris until proven otherwise. 8. Nitroglycerin is a metered-dose spray. This means that each spray of the medication administers the same dosage of mg of medication. 9. Nitroglycerin may be administered at minute intervals up to a total dose of (including what the patient may have self-administered prior to your arrival). 10. The actions of nitroglycerin include all of the following, except: a. Relaxes coronary arteries b. Increase system blood pressure c. Decreases blood return to the heart d. Often causes a mild headache 11. The most common complication of an acute myocardial infarction is. 12. List, in order, the path a drop of blood would take when circulating through the heart and lungs. The starting point has been identified for you. Vena cava Left atrium 9

10 Aorta Right ventricle Pulmonary artery Left ventricle Lungs Right atrium Pulmonary veins 13. Describe your treatment for the following patient. Include any additional assessments you may need: 58 year-old male complains of crushing substernal chest pain that began while watching television. The patient is dyspneic, pale and diaphoretic and states the pain radiates to this left shoulder. No other pertinent history is available, however, upon examination, you note a recent surgical scar in the right lower abdominal region. 10

Cardiac Emergencies. Jim Bennett Paramedic and Clinical Education Coordinator American Medical Response Spokane, Washington

Cardiac Emergencies. Jim Bennett Paramedic and Clinical Education Coordinator American Medical Response Spokane, Washington Cardiac Emergencies Jim Bennett Paramedic and Clinical Education Coordinator American Medical Response Spokane, Washington The Heart -------Aorta Pulmonary Veins---- Superior Vena Cava------ Right Atrium-----