UNIT 3 PDF - Cardiovascular System

Lesson 1: Overview of the Cardiovascular System Action Potential o depolarization – the exchange of ions that creates a positively charged A. Covering and Wall...

Lesson 1: Overview of the Cardiovascular System Action Potential o depolarization – the exchange of ions that creates a positively charged A. Covering and Wall intracellular space and negatively charged extracellular space Pericardium – a double sac of serous membrane that encloses the heart: o repolarization – a state that follow depolarization wherein exchange of visceral pericardium or epicardium and the parietal pericardium. ions reverts back to its resting state 3 layers of the Heart Wall: A. Outer epicardium B. Myocardium C. Endocardium B. 4 Hollow Chambers or Cavities: a. Superior atria/ left and right atrium – “receiving chambers” b. Inferior ventricles/ left and right ventricle – “discharging chambers”; actual pumps of the heart C. Great Vessels: A. Superior and inferior venae cavae – it delivers oxygen-poor blood into the right atrium B. Pulmonary artery or trunk – it delivers oxygen-poor blood pumped by the right ventricle into the lungs. F. Cardiac Cycle, Heart Sounds and Cardiac Output C. Four Pulmonary veins (left and right) – it delivers blood oxygenated Cardiac cycle – refers to the events of one complete heartbeat, during which by the lungs into the left atrium both atria and ventricles contract and then relax. D. Aorta – it delivers oxygenated blood pumped by the left side (left Systole – the contraction phase of heart activity ventricle) of the heart. Diastole – the relaxation phase of heart activity Heart Sounds – “lub” and “dup”. The first sound (lub) is caused by the D. Four Valves of the Heart closing of the AV valves. The second heart sound (dup) occurs when the a. Atrioventricular or AV valves – located between the atria and ventricles semilunar valves close at the end of systole. on each side; it prevent backflow into the atria when the ventricles contract Cardiac Output – the amount of blood pumped out by each side of the 2 types of AV valves include: heart. o Left AV valve or bicuspid valve or mitral valve It is the product of heart rate (HR) and the stroke volume (SV). o Right AV valve or tricuspid valve, has three cusps Stroke volume is the volume of blood pumped out by a ventricle with each heartbeat. b. Semilunar valve – guards the bases of the two large arteries leaving the CO (5250 ml/min) = HR (75 beats/min) x SV (70 ml/beat) ventricular chambers. This prevents arterial blood from reentering the heart. o Pulmonary semilunar valve – it prevents backflow of blood into the Blood Vessels right ventricle after it pumps. o Aortic semilunar valve – it prevents reentry of blood into the left ventricle after pumping. E. Cardiac Circulation Microscopic Anatomy of Blood Vessels Tunics Right and left coronary arteries – it provide oxygenated blood into the a. Tunica interna heart. b. Tunica media Coronary sinus – it delivers deoxygenated blood into the right atrium to c. Tunica externa be oxygenated again by the lungs. Lesson 2: Assessing the Cardiovascular Function 7. Chest Percussion A. Risk Factors 8. Cardiac Auscultation Non – Modifiable Risk Factors 1. Age 1. S1 2. Gender 2. S2 3. Race 3. S3 or ventricular diastolic gallop 4. Family History of CAD 4. S4 or atrial diastolic gallop 5. Murmurs Modifiable Risk Factors 6. Friction rub 1. Hypertension 2. Hyperlipidemia 9. Inspection of the extremities 3. Stress  decreased capillary refill time, pain, paresthesia, numbness, 4. Diet hematoma, peripheral edema, clubbing of the fingers and toes, lower 5. Cigarette smoking extremity ulcers 6. Alcohol 7. Diabetes mellitus 10.Other Systems 8. Obesity 9. Exercise / Lifestyle 1. Dyspnea B. Physical Examination 2. Tachypnea 1. General Appearance 3. Cheyne – Stokes respirations 4. Hemoptysis 2. Inspection of the Skin 5. Cough  Pallor, peripheral cyanosis, central cyanosis, xanthelasma, 6. Crackles decreased skin turgor, cold and clammy skin, ecchymosis, etc. 7. Wheezes 3. Blood Pressure  Pulse pressure – the difference between the systolic and diastolic 1. Hepatojugular reflux pressure 2. Bladder distention  Postural (orthostatic) hypotension C. Common Clinical Manifestations of Cardiovascular Disorders 4. Arterial Pulses  Pulse rate 1. Chest pain  Pulse rhythm 2. Dyspnea or shortness of breath  Pulse quality o Dyspnea on exertion o Orthopnea 5. Jugular venous pulsation o Paroxysmal Nocturnal Dyspnea 3. Peripheral Edema or Weight Gain 6. Heart Inspection and Palpation 4. Palpitations  Aortic area 5. Dizziness/Syncope/ALOC  Pulmonic area 6. Fatigue  Erb’s point  Right ventricular or tricuspid area  Left ventricular or apical area  Epigastric area D. Diagnostic Procedures Related to Cardiovascular Function e. Enzyme Studies 1. Laboratory Tests a. Complete Blood Count - Formerly called SGOT - Elevated level indicates tissue necrosis b. Blood Chemistry and Serum Electrolytes – Phosphokinase (CK-MB) , Mg++ - The most cardiac specific enzyme Blood Urea Nitrogen - An accurate indicator of myocardial damage because it is the first enzyme o End-product of protein metabolism excreted by the kidneys to increase o An indicator of renal function o Elevated BUN reflects reduced renal perfusion from decreased cardiac output or intravascular fluid volume deficit - Most sensitive indicator of myocardial damage but analyzed only in o Normal range is 10 to 29 mg/dL selected patients because of its delayed increase compare to CK- MB o A more sensitive measure of renal function o Normal range is 0.8 to 1.2 mg/dL - Proteins found only in the cardiac muscles - It peaks early during myocardial damage and remains elevated for 1 to 3 c. Blood Coagulation Tests weeks which allow both early and late diagnosis of MI - It valuable in evaluating effectiveness of Coumadin f. Urinalysis - Normal range is 11 to 16 seconds - Assess the effects of cardiovascular disease on renal function and the existence of concurrent renal or systemic diseases Albuminuria – detected with malignant hypertension and CHF - It is the best single screening test for disorders of coagulation Myoglobinuria – supports diagnosis of MI - It is determined to evaluate the effectiveness of heparin. - Normal range is 60 to 70 seconds 2. Chest X-ray  It determines the size, contour and position of the heart. - It has the same purpose as PTT. It is most specific test to evaluate  It does not diagnose acute MI but it can help diagnose some effectiveness of heparin complication (e.g. HF) - Normal range is 30 to 45 seconds 3. Cardiac Fluoroscopy d. Blood Lipids  Facilitates observation of the heart from varying views while it is in motion - A lipid required for hormone synthesis and cell membrane formation  Useful in positioning IV pacing electrodes and for guiding catheter - The client should be on NPO for 10-12 hours insertion during cardiac catheterization. - Normal range is 150 to 250 mg/dL 4. Echocardiography  Uses ultrasound to assess cardiac structure and mobility - Free fatty acids and glycerol stored in the adipose tissues and are a source  No special preparation is required of energy  It is painless and takes approximately 30 to 60 minutes to complete - The client should observe fasting for 10 to 12 hours  The client has to remain still, supine position slightly turned to the left - Normal range is 140 to 200 mg/dL side Cholesterol and Triglycerides: o Low-Density Lipoproteins (LDL) o High-Density Lipoproteins 5. Electrocardiography (ECG) 6. Holter Monitoring - A graphical recording of the electrical activity of the heart. It indicates  A continuous (24hr) ECG monitoring alterations in myocardial oxygenation  The portable monitoring unit is called telemetry unit depolarization; - It is the first diagnostic test done when cardiovascular disorder is suspected  This attempts to assess the activities which precipitate dysrhythmias and time of the day when the client experiences a. 12-Lead ECG dysrhythmias – Lead I, II, III, AVR, AVL, and AVF (traced from limb electrodes) 7. Stress Testing or Exercise Testing – V1,V2,V3,V4,V5, and V6 (traced from chest - ECG is monitored during the exercise on a treadmill or bicycle-like device electrodes) - The purposes of the test are as follows: a) Identify ischemic heart disease b. ECG electrode placement (6 on the chest and 4 on the limbs) b) Evaluate patient with chest pain o RA – right arm (usually red color) c) Evaluate effectiveness of therapy o RF – right foot (usually black color) d) Develop individual fitness program o LA – left arm (usually yellow color) o LF – left foot (usually green color) o V1 – 4th ICS, right sterna border (usually red color) 1. Get adequate sleep the night before the test o V2 – 4th ICS, left sternal border (usually yellow color) 2. Avoid tea, coffee, alcohol on the day of the test o V3 – diagonally between V2 and V4 (usually green color) 3. Avoid smoking and taking nitroglycerine 2 hours before the test o V4 – 5th ICS left MCL (usually brown color) 4. Eat a light meal at least 2 hours before the test o V5 – same level as V4, anterior axillary line (usually black color) 5. Inform the physician if any unusual sensations develop during the o V6 – same level as V4 and V5, midaxillary line (usually violet color) test 6. Rest after the test c. Common ECG terminologies – movement away from the baseline on either 8. Computed Tomography (CT) Scan (+) or (-) direction - Uses x-ray to provide cross-sectional images of the chest, including the Segment – a line between two waveforms heart and great vessels Interval – combination of a waveform and a segment Complex – comprised of several waveforms i. Instruct the patient that the procedure is non-invasive and painless d. Waves, complexes and interval ii. Instruct the patient to remain still during the scanning process P wave – atrial duration is 0.04 to 0.11 secs iii. An IV access line is necessary if contrast enhancement is to be used. PR interval – time of impulse transmission SA node to AV node; duration iv. Ask the client if he has allergy on iodine-rich foods (e.g. seafoods), if is 0.12- 0.20secs contrast is to be used QRS complex – ventricular depolarization; duration is 0.05 to 0.10 secs ST segment – represents the plateau phase of the action potential 9. Magnetic Resonance Imaging (MRI) T wave – ventricular repolarization; duration is 0.16 secs - A non-invasive diagnostic tool that uses a powerful magnetic field and U wave – ventricular diastole computer-generated pictures to image the heart and great vessels e. Abnormal ECG changes o ST segment depression – Angina i. The patient is instructed to remove any jewelries, watches or any other o ST elevation – MI metal items o T wave inversion – MI ii. Interview if the patient has pacemakers, metal plates, prosthetic joints or o Widening QRS – Arrhythmia any metallic implants o Tall/Peak T wave – Hyperkalemia iii. The patient is instructed to be motionless during the procedure o Prominent U wave – Hypokalemia iv. Know if the patient has claustrophobia  10.Cardiac catheterization b. Pulmonary Artery Pressure ses of the test are as follows: - Swan – Ganz catheter is inserted via antecubital vein into the right side a) Assesses oxygen levels, pulmonary blood flow, cardiac output, heart of the heart and is floated into the pulmonary artery. It reflects pressure structures in the left heart. b) Coronary artery visualization - Swan – Ganz catheter is a flow – directed, balloon – tipped, 4 – lumen catheter Angiography – a technique that uses radiopaque contrast agent injected - The catheter allows continuous monitoring of the following: into the vascular system to outline the heart and blood vessels a. Right and left ventricular function b. Pulmonary artery pressures (PAP,PCWP) a. Aortography c. Cardiac output b. Coronary Arteriography d. Arterial – venous oxygen difference c. Right Heart Catheterization  Done by inserting a catheter with or without contrast via a cut down - Normal range: into a large vein, e.g. median cubital or brachial vein a. PAP : 4 – 12 mmHg d. Left Heart Catheterization b. PCWP: 4 – 12 mmHg  Done by passing a catheter into the aorta with or without a contrast - PCWP reading above 25 mmHg suggests impending pulmonary edema via the brachial or femoral artery i. Observe catheter insertion site; culture site every 48 hours i. Provide psychosocial support ii. Assess extremity for color, temperature, capillary filling and sensation ii. Assess for allergy to iodine/ seafood iii. Withhold meals before the procedure iv. Have the client void v. Administer sedative as ordered vi. May experience warm or flushing sensation as the contrast medium is injected vii. “Fluttering” sensation is felt, as the catheter enters the chambers of the heart 11.Hemodynamic Monitoring a. Central Venous Pressure (CVP) Monitoring o Monitors the pressure within the right atrium o Monitors blood volume, adequacy of venous return to the heart, pump function of the right side of the heart o The 0 level of the manometer should be placed at the right, mid-axillary, 4th ICS, the approximate level of right atrium when in supine position o Place the client in supine position o Practice strict asepsis. Cleanse catheter insertion site and change the dressings daily - Normal readings: Superior Vena Cava: 0-12 cm H20 (0-8mmHg) Right Atrium: 5-12 cm H20 - Most common complications of CVP monitoring are infection, pneumothorax, and air embolism