Introduction to the Cardiovascular System PDF

INTRODUCTION TO THE CARDIOVASCULAR SYSTEM NP02L019 ELO A · Version 2.0 Foundations and Adult Health Nursing, 8th ed., pp. 1517-1526 Introduction to Critical Care Nursing, 8th ed., pp. 282-288; pp. 307-311 ENABLING LEARNING OBJECTIVE Explain the structure, function, dia...

INTRODUCTION TO THE CARDIOVASCULAR SYSTEM NP02L019 ELO A · Version 2.0 Foundations and Adult Health Nursing, 8th ed., pp. 1517-1526 Introduction to Critical Care Nursing, 8th ed., pp. 282-288; pp. 307-311 ENABLING LEARNING OBJECTIVE Explain the structure, function, diagnostic exams, and interventions for patients with a cardiovascular disorder. THE CARDIOVASCULAR SYSTEM THE CARDIOVASCULAR SYSTEM The cardiovascular also called circulatory system Transportation system of the body Delivers oxygen and nutrients to the cells Support their individual activities Transports the cells’ waste products to the appropriate organs for disposal. THE HEART ANATOMY The heart is not much larger than a fist Pumps 1,000 gallons of blood every day Beats 100,000 times a day Transports the blood 60,000 miles Located in the chest cavity between the lungs Area called the mediastinum. Two-thirds lies on the left of the midline The wider base of the heart lies above and below the second rib The apex Narrow part of the heart lies inferiorly To the left between the fifth and sixth ribs near the diaphragm THE HEART WALL Made of three layers 1. Pericardium Two-layered serous membrane Between the two layers is fluid that allows the heart to move 2. Myocardium The bulk of the heart wall Thickest and strongest layer Composed of cardiac muscle tissue Contraction of this layer is responsible for pumping blood 3. Endocardium Innermost layer Composed of a thin layer of connective tissue FUNCTIONS The right side receives deoxygenated blood and pumps it to the lungs The left side receives oxygenated blood from the lungs and pumps it throughout the body CHAMBERS The heart is divided into the right and left halves by the septum. There are four chambers Right chamber 1. Right atrium- upper right chamber Receives deoxygenated blood from the entire body 2. Right ventricle- lower chamber Receives deoxygenated blood from the right atrium Left chamber 1. Left atrium- upper chamber Receives deoxygenated blood from the right atrium 2. Left ventricle- lower chamber Receives oxygenated blood from the left atrium though the mitral valve Thickest and most muscular section of the heart Pumps oxygenated blood to all parts of the body VALVES Keep blood moving forward and prevent backflow Atrioventricular valves 1. Tricuspid valve Contains three flaps Located between the right atrium and the right ventricle 2. Mitral valve Contains two flaps Located between the left atrium and left ventricle Semilunar valves 1. Pulmonary valve Contains three flaps Located between the left atrium and left ventricle 2. Aortic valve Contains three flaps Located between he left ventricle and the aorta ELECTRICAL CONDUCTION CONDUCTION SYSTEM OF THE HEART Made up of specialized masses of tissue in the heart wall Allows inherent ability to contract in a rhythmic pattern Called automaticity Cells also respond to stimulus in the same way that nerve cells Called irritability AUTONOMIC CONTROL Autonomic nervous system - control cardiovascular system Sympathetic Increases force of contraction Increases acceleration of AV conduction time Parasympathetic Decrease in sinus node discharge Slows conduction CARDIAC CYCLE Cardiac cycle is a complete heartbeat The two atria contract while the two ventricles relax When the two ventricles contract the two atria relax Relaxation phase Diastole Contraction phase Systole One cardiac cycle = 0.8 seconds HEART SOUNDS Lub dub Sounds are produced by the closure of the valves Lub – the first sound heart is S1 AV valves (tricuspid and mitral) close Dub- the second heart sound S2 Semilunar valves (pulmonic and aortic) close Murmur Swishing sound Can be normal or abnormal Abnormal would indicate ineffective closure of the valves Pacemaker of the heart Causes contraction of the atria. Allows for complete fill contraction of atrium allowing ventricles to fill with blood “Atrioventricular bundle” Divides into left and right bundle branch Branches divide into Purkinje fibers which cause contraction of the ventricles HEART MURMUR Sound described as: Rumbling Blowing Harsh Musical Murmurs graded Grade I (low intensity) to Grade VI (loudest intensity) CHECK ON LEARNING What is meant by automaticity? CHECK ON LEARNING How does irritability play a role in the conduction of the heart? CHECK ON LEARNING Activity: Trace a drop of blood through the heart. CHECK ON LEARNING Which of the heart’s chambers is the thickest and most muscular? a. Right atrium. b. Right ventricle. c. Left atrium. d. Left ventricle. CHECK ON LEARNING A patient reports being diagnosed with a murmur. Which phenomenon can be used to explain what might be the cause of this occurrence? a. Inappropriate closure of the ventricular lock. b. The entrance of blood into partially contracted chambers. c. Ineffective closure of the valves. d. Inadequate levels of blood as it leaves the atria. CIRCULATION SYSTEMIC CIRCULATION Three main types of blood vessels carry blood to and from the heart 1. Arteries Carry blood away from the heart Arterioles (smaller vessels) branch from arteries and carry blood to tissues 2. Veins 3. Capillaries Microscopic vessels within the tissues Exchange oxygen and nutrients for carbon dioxide Join to form tiny veins (venules) that link with large veins to carry blood back to the heart CORONARY CIRCULATION Right and left coronary arteries branch off from the aorta Right coronary artery and its two major branches Perfuse the right atrium, right ventricle, and the posterior portion of the left ventricle Left coronary artery Supplies blood to the anterior wall of the left ventricle and the apex of the left ventricle PULMONARY CIRCULATION Deoxygenated blood is pumped from the right ventricle Returns to the left atrium of the heart via the pulmonary veins Deoxygenated blood in the pulmonary circulation is moved via arteries Oxygenated blood is moved via veins This is opposite of normal circulation COMPONENTS OF CARDIAC OUTPUT Determined by heart rate and stroke volume Preload Afterload Contractility Preload – Degree of ventricular stretch before next contraction Afterload – Amount of resistance the ventricles must overcome to deliver the stroke volume into vasculature Contractility – Strength of myocardial muscle fiber shortening during the systolic phase of the cardiac cycle. BLOOD CIRCULATION CHECK ON LEARNING The right and left coronary arteries branch off what blood vessel? DIAGNOSTIC TESTS DIAGNOSTIC TESTS Chest radiograph Illustrates heart size, shape, position, and outline of shapes Fluoroscopy Allows for observation of movement Angiogram Radiographs the circulatory process Aids in the diagnosis of vessel occlusion The nurse’s role pre-procedure is to explain the procedure After the procedure, check the site of catheter insertion for excess bleeding DIAGNOSTIC TESTS Cardiac catheterization Used to visualize heart’s chambers, valves, vessels, and coronary arteries Aids in diagnosis, prevention of progression of disease and accurate treatment ANGIOGRAM AND CARDIAC CATHETERIZATION Used for diagnosis of cardiac pathology and congenital anomalies Measure pressures within the heart Assessment of the blood in the heart Determinations of valvular defects Ensure patient does not have iodine or shellfish allergy Performed under sterile conditions Requires informed consent ANGIOGRAM AND CARDIAC CATHETERIZATION After the procedure Assess circulation to the extremity used for catheter insertion Check peripheral pulses, color, and sensation of the extremity Observe the puncture site for hematoma and bleeding Monitor vital signs The patient is supine for a pre-determined time and a compression device is applied over the insertion site to prevent hemorrhage ELECTROCARDIOGRAM (EKG) A graphic study of the conduction system within the myocardium to determine transmission of cardiac impulses through the muscles and conduction tissue HEART MONITOR Used to continually monitor heart rhythm and electrical activity Monitors display a visual representation of cardiac activity Telemetry monitor monitors the patient from a remote location by a transmitter The signals are sent to a central location Trained technician or nurse monitors the cardiac activity Most patients that require continuous cardiac monitoring are in a critical care environment or telemetry unit with nursing staff that has been trained in cardiac care. HOLTER MONITOR Used when the patient is discharged to home and monitor heart rhythms Monitor for suspected cardiac disease with normal resting heart rate EXERCISE STRESS TEST Performs prescribed exercise Walking on treadmill, stair climbing THALLIUM SCANNING Thallium is a radioactive isotope that is injected into the patient. Transported actively into normal cells during activity. With ischemia, the thallium will not be picked up Shows up in scans as a “cold spot”. Indicates ischemic or infarcted myocardial tissue ECHOCARDIOGRAPHY Ultrasound directed at the heart. Used to show size, shape, motion and cardiac output (ejection fraction) Define an EKG. LABORATORY STUDIES COAGULATION STUDIES Used for patients receiving anticoagulation medications for: Myocardial infarction Atrial fibrillation Valve replacement Study components Partial prothrombin time (PTT) when patient is taking heparin Prothrombin time (PT) and International ration (INR) when patient is taking Coumadin CARDIAC ENZYMES Proteins - CK, CK-MB, and Troponin I Released blood from the necrotic heart muscle after myocardial infarction CK and CK-MB Also found in skeletal muscle Elevated following trauma, surgery and muscle diseases Troponin I The most cardiac specific Gold standard of cardiac enzymes Sensitive and can indicate a very small amount of myocardial damage Rises in 3 hours after MI Not influenced by skeletal muscle or renal failure B-TYPE NATRIURETIC PEPTIDE (BNP) Hormone excreted by the heart in response to ventricular expansion and pressure overload Level >100 pg/mL indicate heart failure The higher the level, the more severe the heart failure CHECK ON LEARNING Following an angiogram with a left groin insertion site, the nurse will include in the plan of care provisions for: (Select all that apply). a. Checking pedal pulses. b. Ambulating with assistance 2 hours after recovery. c. Checking color and warmth of left leg frequently. d. Sandbagging over insertion site. e. Placing patient in semi-Fowler’s position. CHECK ON LEARNING The nurse outlines which of these cardiac enzymes to be the most cardiac specific? a. Complete blood count (CBC). b. Troponin I. c. B-type natriuretic peptide (BNP). d. Electrocardiography (ECG). INTERVENTIONAL CARDIOLOGY PURPOSE OF INTERVENTIONAL CARDIOLOGY Treatment for Acute Coronary Syndrome Goals: Reperfusion Reduce ischemia Prevent further damage to the myocardium PERCUTANEOUS CORONARY INTERVENTION (PCI) Indication: Unstable angina NSTEMI (with hemodynamic instability) PTCA – Compresses plaque in the coronary artery Increases blood flow to the myocardium Coronary stent – Provides structural support to compress plaque against the artery wall PTCA CORONARY STENT CHECK ON LEARNING How can you differentiate a PTCA from a coronary stent? REVIEW OF MAIN POINTS Anatomy/physiology of the cardiovascular system Electrical conduction system Circulation Diagnostics tests Interventions QUESTIONS ?