Cardiopulmonary System Shannon Ash, RN, BSN

Goal of The Cardiovascular System To ensure delivery of oxygenated blood and nutrients to all the organs and tissues of the body. To carry cellular waste products from the area where they are produced to the kidneys and liver where they are processed for excretion by the body.

Blood Vessels Three types of blood vessels in body: Arteries: The large blood vessels that lead away from the heart. Their walls are elastic, and smaller branches of the arteries are called arterioles.

Blood Vessels Veins: They take de-oxygenated blood back to the heart and lungs to be re-oxygenated. They have thinner walls than arteries, and have valves within their inner walls, to keep blood moving in one direction.

Blood Vessels Capillaries: Are delicate, microscopic vessels that are very thin. Oxygen and nutrients can pass through them!

Blood Circulation Three types: Pulmonary Cardiac Systemic

Cardiac Circulation Inferior/Superior Vena Cava Right Atrium Right Ventricle Pulmonary Artery (to lungs) Pulmonary Vein Left Atrium Left Ventricle Aorta (to rest of body)

Circulation De-oxygenated blood flows through the venae cavae (plural) Superior vena cava and Inferior vena cava into the right side of the heart, through to pulmonary artery which divides the blood to each lung, and the branches keep getting smaller and smaller until it reaches the lung capillaries. While the blood is flowing through the lung capillaries, it picks up fresh oxygen, and heads back to the heart via the pulmonary veins. This fresh, oxygen-rich blood goes back to the left side of the heart where it is pumped out to the rest of the body through the aorta.

Circulation When blood flows out the aorta, it flows through arteries to smaller vessels called arterioles and to smaller vessels called capillaries. At the capillary level, the fresh oxygen is exchanged for carbon dioxide along with other cellular waste products, and the blood begins to return to the heart via the veins.

Cardiac Anatomy The heart is a muscular pump, made up of four chambers: two atria (right and left) and two ventricles (right and left) In between the atria (on top) and the ventricles (on the bottom) are valves. On the right side of the heart the valve is called the tricuspid valve. On the left side of the heart the valve is called the mitral valve.

Cardiac Anatomy Points Left ventricle is largest and most muscular of heart chambers. The atria and ventricles are separated by a wall of tissue called the septum. The heart has three layers that make it up: the endocardium (inside the heart); the myocardium (middle, muscular layer); and the pericardium, a sac that surrounds the heart. The pericardium has two layers; the visceral pericardium which adheres to the heart, and the parietal pericardium which lines the outer fibrous coat. The pericardial cavity (lies between the visceral and the parietal pericardium) contains 10 - 15cc of fluid, which lubricates the membrane of the heart as it beats.

Physiology of the Heart Each heartbeat has two phases: systole (contraction) and diastole (relaxation). Diastole occurs when the walls of the ventricle relax, and blood flows into the heart from the venae cavae and the pulmonary veins. Systole occurs after that, as the walls of the right and left ventricles contract to pump blood into the pulmonary artery and the aorta.

Principles related to Cardiac Conduction Heart muscle has properties that no other muscle in body has: principle of automaticity, meaning that heart muscle actually initiates the impulse for the heart to beat. Specialized areas in the heart are responsible for this beat initiation.

Cardiac Conduction System Primary responsibility for initiating impulses comes from the sinoatrial node. Also called the SA node, and the pacemaker of the heart. The electricity produced in the SA Node travels through the atria down through the AV Node, and down through the Bundle of His, and the right & left bundle branches, which depolarizes the ventricles and produces the contraction.

Heart & Blood Vessel Abnormal Conditions Arrhythmias: Abnormal heart rhythms. Heart Block: Failure of proper conduction of impulses through the AV node to the Bundle of His. May require a cardiac pacemaker. Atrial Flutter: Rapid, regular contractions of atria or ventricles. Heart rates can reach up to 300 beats per minute . Atrial Fibrillation: Rapid, random, irregular contractions of the heart. May require a blood thinner to be taken. May require an AICD or cardiac ablation. Can have heart rates of greater than 350 “beats” or quivers per minute.

Congential Heart Diseases Coarctation of the aorta: Narrowing of the aorta, requiring surgical correction. Patent ductus arteriosus: A small duct between the aorta and the pulmonary artery, remains open. This must be closed surgically. Septal defects: Small holes in the septa between the atria or the ventricles. May spontaneously close or may require surgery. Tetralogy of Fallot: A malformation of the heart involving four distinct defects: Pulmonary artery stenosis Ventricular septal defect Shift of the aorta to the right Hypertrophy of the right ventricle Baby will be blue or cyanotic at birth. Surgery is required to repair.

Heart & Blood Vessel Abnormal Conditions Congestive Heart Failure: The heart is unable to pump the required amount of blood to the body. Can be right heart failure or left heart failure. Symptoms are related to the side of the failure. Coronary Artery Disease: Disease of the arteries surrounding the heart. Plaque in the coronary arteries and can block them completely, causing a heart attack. Endocarditis: Inflammation of the inner lining of the heart caused by bacteria. Hypertensive heart disease: High blood pressure that affects the heart. Mitral Valve Prolapse: Improper closure of the mitral valve when the heart is pumping blood. Murmur: An extra heart sound heard between normal beats.

Heart & Blood Vessel Abnormal Conditions Pericarditis: Inflammation of the membrane that surrounds the heart. Rheumatic heart disease: Heart disease that is caused by rheumatic fever. Aneurysm: An area of an artery that balloons out, and causes a weakness in the vessel. Peripheral Vascular Disease: Blockage of arteries in the lower extremities due to atherosclerosis. Raynaud Phenomenon: Short episodes of pallor & numbness in the fingers and toes due to temporary constriction of arterioles in the skin. Varicose veins: Abnormally swollen and twisted veins that occur in the legs. Angina Pectoris: Chest pain that is temporary.

Cardiac Related Terms Bruit: An abnormal heart sound heard with auscultation. Claudication: Pain, tension, and weakness in a leg after walking, but when at rest there is no pain. Emboli: Collections of material (clots or other material) that can travel through the blood system and suddenly block a blood vessel. Infarction: Area of dead tissue. Occlusion: Closure of a blood vessel. Palpitations: Uncomfortable sensations in the chest caused by irregular heartbeats. Patent: Open Petechiae: Small, pinpoint hemorrhages. Thrill: A vibration felt when an area is palpated. Vegetations: Collections of debris that attach to the endocardium and heart valves.

Cardiac Drugs Angiotensin-converting enzyme inhibitors (ACE): These drugs reduce blood vessel constriction. They are used to treat high blood pressure. Beta-Blockers: Drugs used to treat angina, hypertension, and arrhythmias. They help the heart beat more slowly and with less force. Calcium Channel Blockers: Drugs used to treat angina and hypertension. They dilate blood vessels by blocking the influx of calcium. Digoxin: A drug used to correct arrhythmias and improve the strength of the heartbeat. Nitrates: Drugs used to treat angina. They dilate blood vessels and give the heart more oxygen. i.e. nitroglycerin

Tests & Procedures Angiography: Dye is injected into a vessel and xrays are taken. Doppler Ultrasound: An instrument focuses sound waves on a blood vessel to measure blood flow. Echocardiography: Ultrasound waves are used to see pictures of the heart and it’s structures. Can be across the chest or down the throat. Lipid Tests: A blood test for cholesterol and triglycerides. Lipoprotein electrophoresis: Separates out different types of fats in the bloodstream. Serum enzyme tests: Blood tests to measure levels of injured cardiac muscle in MI patients.

Tests & Procedures Positive Emission Tomography: (PET) Scan: IV contrast is given, then IV glucose is given. These show up in the heart muscle, showing blood flow and heart structures and functions. Cardiac MRI: magnetic waves beamed at heart showing structures and disease. Thallium 201 Scintigraphy: Thallium 201 is given and then measured by a scanner to show damaged areas of the heart. Technetium 99m or MUGA scan: Radioactive test shows ventricular function.

Tests & Procedures Cardiac catheterization: A small flexible tube is passed into the coronary arteries of the heart and a dye is used to show blockages. Cardioversion: Electrical energy is applied to heart at a specific time to change heart rhythm. Coronary Artery Bypass Surgery: Blood vessels from other areas (legs or donor) are used to bypass blocked areas of coronary arteries. Page 401. Defibrillation: Electrical energy is applied to heart to re-start heart rhythm. Electrocardiography: A process of recording electrical processes in the heart. Endarterectomy: The surgical removal of the innermost lining of an artery when it is occluded with plaque or clots. Heart transplantation: A donor heart from a brain dead person is placed into a living person and restarted.

Tests & Procedures Holter Monitoring: A very small ECG machine measures electrical activity, usually for 24 hours. Can be done at home. Percutaneous transluminal coronary angioplasty: A balloon is inserted (on a wire) into a coronary artery to smoosh or squish the plaque that’s blocking the artery. Stress Test: Places person on treadmill or similarly elevates heart function, and takes ECG, blood pressure, and other readings while heart is stressed. Thrombolytic Therapy: Clot-busting drugs are given to break up clots that could be causing a heart attack, stroke, or reduced blood flow to an area.

PTCA

Angioplasty

Cardiac Bypass

Cardiac System The cardiac system is a complex and unique system. Nearly all changes that occur in the body affect the cardiac system in some way. It is a constantly adapting system!