Ch. 20 Heart Failure and Circulatory Shock Flashcards
What is heart failure?
Heart Failure is a clinical syndrome that occurs when the heart is unable to pump adequate blood to meet the metabolic demands of the body
What is the cardio-renal model of heart failure?
It views heart failure as a disorder of excessive sodium and water retention (outdated model).
What is the view of heart failure as a hemodynamic disorder?
It looks at the reduced cardiac output or afterload.
What is the current understanding of heart failure?
heart failure as a neurohormonal model
What is “preload”?
“End diastolic volume”
What is “afterload”?
Amount of force needed to eject filled heart.
What determines afterload?
Determined by SVR and ventricular wall tension.
What determines preload?
Determined by venous return to the heart.
What is “contractility”?
Performance of cardiac muscle.
What are four general types of heart failure?
Systolic vs. diastolic
Dilated vs. hypertrophic
Left vs. right
High-output vs Low-output
What is systolic heart failure?
Impaired ejection of blood. Presence of signs and symptoms of heart failure with an ejection fraction of
What are the causes of systolic heart failure?
Muscle issues
Volume overload
Pressure overload
What are some of the muscle problems that can cause heart failure?
CAD, myocarditis, cardiomyopathy, conduction issues
What are some volume overload problems that can cause heart failure?
Valvular insufficiency, kidney disease
What are some pressure overload problems that can cause heart failure?
HTN
valvular stenosis
Pulmonary disease
What is diastolic heart failure?
Impaired filling during diastole
Presence of signs and symptoms of HF in the absence of systolic dysfunction (LVEF > 40%)
Myocardium is “stiff” (and often hypertrophied) and does not relax normally after contraction
What are the causes of diastolic heart failure?
Impaired ventricular stretch
Increased wall thickness
Delayed diastolic relaxation
What are some disorders that cause impaired ventricular stretch, that can cause diastolic heart failure?
pericardial effusion, pericarditis, amyloidosis
What are some disorders that cause increased heart wall thickness, that can lead to diastolic heart failure?
hypertrophy, myopathy
What are some factors that cause delayed diastolic relaxation, that can lead to diastolic heart failure?
Aging, CAD
Why is diastolic heart failure aggravated by tachycardia?
The heart already has a hard time filling properly, and in tachycardia there is even less time for the heart to fill between pumping
What are the risk factors for diastolic heart failure?
Women, obesity, HTN, diabetes mellitus
What is the main difference between systolic heart failure and diastolic heart failure?
Systolic = an ejection problem Diastolic = a filling problem
What do systolic and diastolic heart failure have in common?
A decreased cardiac output.
What are the CNS symptoms of left ventricular dysfunction (left-sided heart failure)?
Fatigue, weakness, confusion, dizziness (worsens over day)
What are the cardio-vascular manifestations of left ventricular dysfunction (left-sided heart failure)?
Hypotension, angina, tachycardia, palpitations, pallor, weak peripheral pulses, cool extremities, S3/S4
What are the renal complications of left ventricular dysfunction (left-sided heart failure)?
Oliguria (less urine) during the day
Night time = frequent urination
What are the manifestations of left ventricular dysfunction (left-sided heart failure)?
SOB (initially during exertion/orthopnea/PND) Cough, “cardiac asthma” (worse at night) Inspiratory crackles/expiratory wheezes Tachypnea Frothy/pink sputum (pulmonary edema)
What are the manifestations of right ventricular dysfunction (right-sided heart failure)?
Jugular vein distention/elevated central venous pressure
Enlarged liver and spleen
Dependent edema
Ascites
Polyuria at night
Weight gain
Hepatojugular reflux (HJR)
BP changes
Elevated BP (excess volume)
Decreased BP (decreased cardiac output)What is high-output heart failure?
Caused for excessive need for cardiac output. The heart compensates, and then fails from too much compensation.
What are the causes of high-output heart failure?
Severe anemia
Thyrotoxicosis/thyroid storm
What is low-output heart failure?
Caused by conditions decreasing pumping ability
What are the causes of low-output heart failure?
Coronary artery disease
Cardiomyopathy
What is the Frank-Starling mechanism of compensating for heart failure?
+Increased preload (end diastolic volume) will increase stroke volume.
-Stretch increases wall tension, increasing oxygen requirements
What is the sympathetic nervous system mechanism of compensating for heart failure?
+Increase in circulating catecholamines increase HR, contractility, peripheral vascular resistance, stroke volume, cardiac output.
-Increased workload
What is the renin-angiotensin-aldosterone system of compensating for heart failure?
+Increased concentration of renin, angiotensin II & aldosterone d/t decreased renal perfusion
-Increased preload, increased workload
What is the natriuretic peptide (ANP&BNP) mechanism of compensating for heart failure?
+Released in response to stretch, pressure, fluid overload (promote diuresis)
-Decreases preload, decreases cardiac output
What is the endothelins method of compensating for heart failure?
+ Responds to pressure changes (v/c, myocyte hypertrophy, ANP & catecholamine release)
- Increased workload
What is ventricular remodeling? (Pros and cons)
Pros:
Symmetric hypertrophy
Cons: Pressure overload (hypertension) Volume overload (dilated cardiomyopathy)
What is symmetric hypertrophy in ventricular remodeling?
Proportionate increase in muscle length and width (athletes)
What is pressure overload (hypertension) in ventricular remodeling?
Concentric hypertrophy d/t replication of myofibrils, thickening of myocytes
Increase in wall thickness (hypertension)
What is volume overload (dilated cardiomyopathy) in ventricular remodeling?
Concentric hypertrophy d/t replication of myofibrils, disproportionate elongation of muscle cells
What are the late manifestations of heart failure?
Cyanosis
Clubbing of fingers
Cachexia/Malnutrition
Arrhythmias/Sudden Cardiac Death
Why does late stage heart failure cause cyanosis?
Due to pulmonary edema, vasoconstriction, decreased oxygen availability
Why does late stage heart failure cause cachexia/malnutrition?
CNS factors (not getting enough oxygen to the brain, supresses apetite) Liver and GI congestion
Why does atrial fibrillation occur?
Myocardial infarction
Heart failure
Valvular damage
What is happening in the heart during atrial fibrillation?
Quivering muscle (atria)
Poor emptying of atria
Poor filling of ventricle resulting in decreased cardiac output
How does a patient in atrial fibrillation present?
Irregulary irregular HR Pulses will be irregular with varying strenghts Low BP Possibility of angina Possibility of thrombi
What is acute pulmonary edema?
Accumulation of capillary fluid in alveoli that impairs gas exchange and limits lung expansion.
What are the manifestations of acute pulmonary edema?
Short of breath, dyspnea, tachycardia Tachycardia, moist/cool skin Fine to coarse crackles Frothy, blood-tinged sputum Cyanotic lips, nailbeds CNS: confusion, stupor
What are the diagnostic methods for heart failure?
History, physical assessment
Signs and symptoms
ECG
CXR
Echocardiography
Ejection fraction
Wall motion, thickness
Chamber size
Structural defects (valves, tumors, etc.)
Blood tests: BNP, CBC
Central venous pressure/jugular vein distension
Pulmonary artery catheter pressures/volumesWhat are the non-pharmacological treatments for heart failure?
Exercise program, fluid/Na restriction, weight control, dietary counseling
Non-surgical and surgical medical management
What are the pharmacological treatments for heart failure?
Diuretics, ACE inhibitors, cardiac glycoside (digoxin), ARBs, B-blockers
Oxygen therapy
What is circulatory failure/shock?
Acute failure of the circulatory system to supply tissues and organs with an adequate blood supply resulting in hypoxia.
What is the cellular response to shock affecting anaerobic energy production?
Cytoplasm uses glucose to create ATP and pyruvate
Less efficient
What is the cellular response to shock affecting aerobic energy production?
Oxygen and pyruvate create ATP in mitochondria
If no oxygen, pyruvate converts to lactic acid
What is cardiogenic shock?
Heart failure, uncompensated (can be due to other shock situations)
What are causes of cardiogenic shock?
Myocardial Infarction Myocardial contusion Acute mitral valve regurgitation - d/t pappilary muscle rupture Arrhythmias Severe dilated cardiomyopathy Cardiac surgery
What are the cardiovascular manifestations of cardiogenic shock?
Decreased stroke volume, mean arterial pressure, systolic blood pressure
Narrow pulse pressure
Normal diastolic blood pressure
Cyanosis (lipds, nailbeds, skin)
Elevated central venous pressure/pulmonary capillary wedge pressure
Dysrhythmias
What are the renal manigestations of cardiogenic shock?
Oliguria, anuria
What are the CNS manifestations of cardiogenic shock?
Altered mentation (GNS 15-0)
What is the treatment for cardiogenic shock?
Fluid volume management
Treat cause and symptoms
Improve cardiac output, avoid increasing workload of heart
What is hypovolemic shock?
Any condition which decreases blood volume >15%
What are external ways to lose blood volume?
Hemorrhage, burns, severe dehydration/vomiting/diarrhea
What are internal ways to lose blood volume?
3rd spacing, hemorrhage
What are the immediate compensation methods for hypovolemic shock?
SNS, RAAS, hypothalamus, fluid shift
What are the cardiovascular manifestations of hypovolemic shock?
Tachycardia, weak/thready pulses
Skin cool/clammy/mottled
Hypotension
Decreased CVP
What are the CNS manifestations of hypovolemic shock?
ADH release, thirst Altered mentation (CGS 15-0)
What are the respiratory manifestations of hypovolemic shock?
Tachypnea, deep resps
What are the renal manifestations of hypovolemic shock?
Oliguria, anuria
How do we treat hypovolemic shock?
Treat the cause
Increase oxygen delivery by maintaining adequate vascular volume
What are three ways to increase oxygen delivery by maintaining adequate vascular volume?
IV crystalloids IV colloids (rbc’s, plasma volume expanders) Vasoactive pharmacology (not usually recommended)
What is obstructive shock?
Mechanical obstruction of blood to or through great veins, heart, lungs
What are some causes of obstructive shock?
Pulmonary embolus
Dissecting Aortic aneurism
Tamponade
Pneumothorax
Atrial myxoma (benign tumour of the heart)
Abdominal evisceration (your guts come out)
What is neurogenic shock?
Rare, often transitory depending on the cause
Decreased SNS control of vessel tone
What are the causes of neurogenic shock?
Brain stem defect Spinal cord injury Drugs General anesthesia Hypoxia Insulin reaction
What is anaphylactic shock?
Immunological mediated reaction of histamine release causing
v/d of arterioles and venuoles, and
Increased capillary permeability
What are the manfestations of anaphylactic shock?
Manifestations dependent on: Level of sensitivity, Rate/quantity of antigen exposure
Pruritis, urticarial
Angioedema
Laryngeal edema/bronchospasm
Rapid hypotension; circulatory collapse
What are the treatments of anaphylactic shock?
Remove cause
Epinephrine, oxygen, antihistamines, corticosteroids
What is septic shock?
Systemic inflammatory response to a severe infection
How does septic shock happen?
Neutrophils increase capillary permeability & damage to endothelial cells result
Cytokines, nitric oxide, & coagulation products are released, damaging cells/tissues and causing massive vasodilation
What are the cardiovascular manifestations of septic shock?
Vasodilation (decreased SVR), hypovolemia, hypotension, tachycardia, skin flushed, edema
What are the CNS manifestations of septic shock?
Pyrexia, abrupt change in mentation
What are the renal manifestations of septic shock?
Oliguria, anuria
What are the hematological manifestations of septic shock?
Leukocytes, metabolic acidosis, thrombocytopenia
What are the treatments for septic shock?
Treat cause Support circulation Oxygen Aggressive fluids Aggressive management of fluids Inotropes Recombinant human activated protein C (rhAPC), a naturally occurring factor that Inactivates clotting factors Inhibits cytokine production
What are the complications of shock?
Acute respiratory distress syndrome Acute renal failure GI tissue damage d/t hypoxia Disseminated intravascular coagulation Multi-organ dysfunction syndrome
What is acute respiratory distress syndrome?
Rapid onset of hypoxemia unrelieved by supplemental oxygen
Ventilation-perfusion mismatch
Atelactasis, impaired gas exchange, fluid limits inflation
What is the treatment for acute respiratory distress syndrome?
Mechanical ventilation, oxygen
How does shock cause acute renal failure?
Ischemia/injury of renal tubules >20 minutes
How do we treat GI tissue damage due to hypoxia that occurs as a result of shock?
Proton pump inhibitors, histamine-2 receptor agonists
What is disseminated intravascular coagulation?
Widespread activation of coagulation cascade (not the primary disease)
How is disseminated intravascular coagulation treated?
anticoagulation, platelets, plasma
What is multi-organ dysfunction syndrome?
Failure of multiple organs such that homeostasis cannot be achieved.
