NUR 1211C ADULT HEALTH NURSING LECTURE 13-14 CARDIOVASCULAR SYSTEM: THE HEART 8 th Edition: Ch. 33, 34, 35 7 th Edition: Ch. 35, 36, 37
Chapter (33) (35) Assessment of the Cardiovascular System
Surface Anatomy of the Heart
Blood Flow Through the Heart
Cardiac Valves 1. Tricuspid valve 2. Mitral valve 3. Pulmonic valve 4. Aortic valve
Mean Arterial Pressure (MAP) • Must be at least 60 mm Hg to maintain adequate blood flow through coronary arteries and perfuse major organs (brain) • Formula: SBP + 2DSP 3 For example: If a patient’s BP is 110/70, the MAP is: 110 + 2(70) = 110 + 140 = 250 = 83 3 3 3
Sequence of Events During the Cardiac Cycle
Mechanical Properties of the Heart • Stroke volume • Heart rate • Cardiac output • Preload : venous return and heart compliance (elasticity) • Afterload : Impedance: peripheral vascular resistance • Myocardial contractility
Mechanical Properties of the Heart (cont’d) • Cardiac Index (CI) = Cardiac Output ÷ Body Surface Area (BSA) • CI normal range = 2.7 to 3.2 L/min/m 2 BSA
Cardiac Output • Amount of blood pumped from left ventricle per minute • Heart Rate × Stroke Volume
Arterial System • Blood pressure is force of blood exerted against vessel walls
Blood Pressure Regulation • Autonomic nervous system: – Baroreceptors – Chemoreceptors—hypercapnia • Renal system • Endocrine system • External factors also affect BP
Cardiovascular System Assessment • Patient history • Nutritional history • Family history and genetic risk • Modifiable and nonmodifiable risk factors for cardiovascular disease • Current health problems – Pain, discomfort – Dyspnea, DOE, orthopnea, PND – Fatigue – Palpitations – Edema – Syncope – Extremity pain
Point to Remember… • Best indicator of fluid balance is weight • 2.2 lb = 1 kg = 1 L of fluid
Cardiovascular System Physical Assessment • General appearance • Skin – Cyanosis, rubor; pallor • Extremities – Clubbing, edema • Blood pressure – Hypotension and hypertension – Postural (orthostatic) hypotension
Precordium • Assessment: – Inspection: point of maximal impulse – Palpation and percussion: not done by the nurse – Auscultation • Normal heart sounds: S 1 and S 2 caused by closure of atrioventricular valves and semilunar valves; indicate the beginning and end of systole • Paradoxical splitting: (S 2 ) early closure of pulmonic valve or delay in aortic valve closure; caused by MI, left bundle-branch block, aortic stenosis, aortic regurgitation, and right ventricular pacing. • Pericardial friction rub: Sign of friction between both layers of pericardium, indicate pericarditis, and can be heard despite the patient hold breath (if it stops while holding breathing, it is a pleural rub). Usually heard on precordium.
Precordium (cont’d) • Assessment (cont’d) – Auscultation • Gallops and murmurs: S 3 is a ventricular gallop, heard at the beginning of diastole, caused by fast ventricular filling in a noncompliant ventricle; it is a normal finding in people younger than 35, and a sign of heart failure in older people.
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- Summer '19
- Cardiology, heart rate, Nursing Considerations