CARDIOVASCULAR MODULE: CARDIAC FAILURE Adult Medical-Surgical Nursing

Factors affecting Cardiac Efficiency Preload Contractility Afterload

Preload The degree of stretch of the cardiac muscle fibres at the end of diastole (filling of ventricles) Increased preload → increased stroke volume

Preload Determined by: Venous return: the blood volume available Compliance: elasticity and stretch of cardiac muscle (Compliance is reduced when infarcted cells following Myocardial Infarction are replaced by fibrous tissue)

Contractility The force of contraction of the cardiac muscle Determined by the number and condition of myocardial cells: these function in syncitium (harmony)

Afterload The pressure the cardiac muscle must exert to overcome vascular resistance ↑ afterload = ↓ stroke volume ↓ afterload = ↑ stroke volume

Afterload Determined by: Diameter/ distensibility of the aorta and great vessels: (vasoconstriction, plaque or hypertension increase afterload therefore increase workload on the heart) Function of pulmonary/ aortic valves: (pulmonary or aortic stenosis ↑ afterload and workload of heart muscle to eject blood)

Cardiac Failure Cardiac failure is the inability of the heart to pump adequately to meet the needs of the tissues for O2 and nutrients

Cardiac Failure: Classification Left ventricular failure (left heart failure) Congestive heart failure (right heart failure)

Left Ventricular Failure: Description Inadequate pumping ability of the left ventricle

Left Ventricular Failure: Aetiology Usually follows myocardial infarction: (damaged myocardial cells affect stretch and contractility) Hypertension Valvular dysfunction (stenosis or incompetence): increases afterload/ workload for cardiac muscle

Left Ventricular Failure:Pathophysiology Increased workload of left ventricle as: Inefficient muscular sac Pumping against ↑ afterload ↑ left ventricular end-diastolic pressure (difficulty pumping blood into aorta → increasingly more volume in left ventricle) leads to Back pressure ↑ volume and pressure in left atrium and pulmonary vein: ↑ pulmonary hydrostatic pressure → pulmonary oedema

Pulmonary Oedema An accumulation of fluid in the lung alveoli (the patient is virtually drowning in his secretions – fluid mixes with air) Occurs more after lying down at night which ↑ venous return and volume flowing to the lungs (Pulmonary pressure is already high from left ventricular failure) → extreme crisis

Hypotension (low cardiac output) Tachycardia Pallor, sweating, cyanosis (hypoxaemia) Severe dyspnoea/ orthopnoea: Breathing is rapid, moist and noisy Copious frothy bloodstained sputum Restlessness, confusion, anxiety Pulmonary Oedema: Clinical Manifestations

Pulmonary Oedema:Diagnosis Emergency: Clinical picture immediately recognised Patient history (from family) Chest Xray: pulmonary congestion and enlarged left ventricle Blood gases (ABG) Later echocardiography

Aims of Emergency Management Emergency management of pulmonary oedema aims to: ↑ pumping ability of left ventricle ↑ respiratory exchange

Emergency Management Digitalis or Dobutamine ↑ contractility O2 (intubation if necessary) Morphine IV: vasodilator and relieves anxiety (with anti-emetic cover) Diuretics: IV Frusemide for rapid effect. This also causes vasodilation and pooling of blood in peripheries reducing preload

Nursing Responsibilities Sit patient upright, table in front/ legs dangling ( ↓ venous return) Medications and O2 Vital signs, pulse oximetry Blood ABG, chemistry Strict fluid balance (catheter if necessary) Support, reassurance, safety are vital (do not leave the patient)

Congestive Heart Failure

Congestive Heart Failure: Description Congestive heart failure is failure of the right as well as the left side of the heart

Congestive Heart Failure: Pathophysiology Left side: pulmonary overload and congestion → pulmonary oedema Right side: systemic overload/ congestion of viscera and peripheries The heart cannot accommodate venous return → peripheral oedema, ascites, hepatomegaly

Congestive Heart Failure: Clinical Manifestations Fatigue, weakness, dizziness Cyanosis, dyspnoea on exertion Oedema: peripheral (ankles, legs, thighs, sacral) ascites, pulmonary Weight gain Distended neck veins ( ↑ JVP) Oliguria ( ↓ renal perfusion) Hepatomegaly, nausea, anorexia

Congestive Heart Failure: Diagnosis History and clinical picture Chest Xray ECG Echocardiograph Liver and renal function tests

Congestive Heart Failure: Management Aims to: ↓ workload on the heart (vasodilators and diuretics) ↑ contractility ↓ excessive fluid (diuretics)

Congestive Heart Failure: Management O2 therapy Restrict fluids/ salt ↓ smoking Rest (exercise as tolerated to improve circulation) Vasodilators: Nitroglycerin, ACE inhibitors, B-blockers Digitalis/ Dobutamine Diuretic

CHF: Nursing Responsibilities General nursing care if dependent patient Assist gentle exercise Avoid elastic stockings as ↑ preload Comply with fluid/ dietary restrictions Daily check weight, girth measurement, leg oedema / lung sounds Monitor intake and output; vital signs Medications: instruct Psychological support and ensure safety