Unit 8 Cardiovascular Sytem Flashcards
What is circulatory shock?
An acute failure of the circulatory system to supply the peripheral tissues and organs of the body with an adequate blood supply, resulting in cellular hypoxia
Describe manifestations of shock (fig 20.5 handout). Requested access from Alice April 14th.
Hypovolemic - Direct loss of effective circulating blood volume leading to:
- A rapid, weak, thready pulse due to decreased blood flow combined with tachycardia (decrease BP with increased HR)
- Cool, clammy skin due to vasoconstriction and stimulation of vasoconstriction
- Rapid and shallow breathing due to sympathetic nervous system stimulation and acidosis
- Hypothermia due to decreased perfusion and evaporation of sweat
- Thirst and dry mouth, due to fluid depletion and
- Cold and mottled skin (Livedo reticularis), especially extremities, due to insufficient perfusion of the skin
- The severity of hemorrhagic shock can be graded on a 1-4 scale on the physical signs. This approximates to the effective loss of blood volume.
- [edit]
Cardiogenic
- Distended jugular veins due to increased jugular venous pressure
- Weak or absent pulse
- Arrhythmia, often tachycardic
- Pulsus paradoxus in case of tamponade
What are the four types of circulatory shock?
Hypovolemic
- Loss of whole blood
- Loss of plasma
- Loss of extracellular fluid
Obstructive
- Inability of heart to fill properly
- Obstruction to outflow from the heart
Distributive
- Loss of sympathetic vasomotor tone
- Presence of vasodilating substance in the blood
- Presence of inflammatory mediators
Cardiogenic shock
- By an alteration in cardiac function
What are the complications of shock?
- Acute respiratory distress syndrome
- Acute renal failure
- Gastrointestinal complications
- Disseminated intravascular coagulation
- Multiple organ dysfunction syndrome
What is MODS?
- Multiple organ dysfunction syndrome
- Presence of altered organ function in an acutely ill patient such that homeostasis cannot be maintained without intervention
- Kidneys, lungs, liver, brain, and heart
- Pathophysiology: A definite explanation has not been found. Local and systemic responses are initiated by tissue damage. Respiratory failure is common in the first 72 hours after the original insult. Following this one might see hepatic failure (5–7 days), gastrointestinal bleeding (10–15 days), and renal failure (11–17 days)
What is heart failure?
Failure of the heart as a pump that result in inadequate perfusion of tissues
What are compensatory mechanisms that try to maintain cardiac output during heart failure?
Compensatory or adaptive mechanisms
- Activation of neurohumoral influences such as the sympathetic nervous system
- The renin–angiotensin–aldosterone mechanism
- Natriuretic peptides (refers to a peptide which induces natriuresis, the discharge of sodium through urine)
- Locally produced vasoactive substances
- Myocardial hypertrophy and remodeling
Explain the mechansism that compensate for HF
- Frank-Starling mechanism: an intrinsic adaptive response which serves to adjust each ventricular output to its inflow by increasing the force of contraction of the myocardium proportionally to any increase in the length of the muscle fibers.
- RAA System
- Myocardial hypertrophy
- Sympathethic reflexes
How can hrt failure be described or identified?
- High-output or low-output failure
- Systolic or diastolic failure
- Right-sided or left-sided failure
- Chronic or acute
Describe acute and chronic heart failure.
Acute heart failure
- Develops rapidly; immediately life threatening
- Results from cardiopulmonary bypass surgery, acute infection (sepsis), acute myocardial infarction, valve dysfunction, severe arrhythmias
Chronic heart failure
- Long-term condition associated with the heart undergoing adaptive responses
- Adaptive response can make heart failure worse
What are the primary issues that cause left or right sided hrt failure?
Right side - primary issue is with pulmonary semilunar valve, backup of blood to systemic system, edema of extremities
- Congenital heart diseases (VSD, PDA)
- Secondary to left sided heart failure (increase in left ventricle filling pressure is reflected back in the pulmonary circulation)
- Massive pulmonary embolism
- Chronic pulmonary disease (Cor pulmonale)
Left side - primary issue is with aortic semilunar valve, backup of blood to pulmonary vein, pulmonary hypertension
- Ischemic heart diseases
- Hypertensive heart diseases
- Cardiomyopathy
- High-output states (thyrotoxicosis, anemia)
What are the manifestations of right and left side heart failure?
What is the pathogenesis and clinical manifestations of right-sided heart failure?

- fluid builds up in tissues as peripheral edema
- systemic venous congestion
- peripheral edema
- liver congestion – hepatomegaly
- fluid accumulation in the body cavities
- raised jugular venous pressure
What is the pathogenesis and the clinical manifestations of left sided heart failure?
- blood remains in left ventricle
- blood backs up into lungs as pulmonary edema – pulmonary congestion
- suffocation and lack of oxygen to the lung tissues
Causes of HF
Myocardial disease
- Cardiomyopathies
- Myocarditis
- Coronary insufficiency
- Myocardial infarction
Valvular heart disease
- Stenotic valvular disease
- Regurgitant valvular disease
Hypertension
Congenital heart defects
Constrictive pericarditis
What are backward and forward effects of heart failure?
backward heart failure a concept of heart failure emphasizing the causative contribution of passive engorgement of the systemic venous system, as a result of dysfunction in a ventricle and subsequent pressure increase behind it.
forward heart failure a concept of heart failure that emphasizes the inadequacy of cardiac output relative to body needs and considers venous distention as secondary.
What is Cor Pulmonale?
refers to right sided heart failure resulting from primary lung disease and long standing pulmonary hypertension
- signs of right sided heart failure
- signs of chronic airway obstruction
- signs of polycythemia
How does pulmonary hypertension contribute to right sided heart failure?
Compare high output and low output heart failure.
High output: the heart increases its output but the body’s metabolic needs are still not met
- anemia
- hyperthyroidism
- beriberi (thiamine, vitamin B1 deficiency)
Low output: common causes:
- ischemic heart disease
- cardiomyopathy
Compare systolic and diastolic heart failure.
Systolic failure: a decreased in myocardial contractility
ejection failure
Causes:
- ischemic heart diseases
- valvular insufficiency
- pressure overload such as hypertension
Diastolic failure: relaxation is abnormal
conditions that impede relaxation
Causes:
- pericardial effusion, constrictive pericarditis
- aging
Describe the cardiac cycle
http://en.wikipedia.org/wiki/File:Wiggers_Diagram.png
- early diastole: DIASTOLE, AV valves open, SL valves closed
• whole heart is relaxed
• ventricles are expanding and filling - atrial systole: DIASTOLE, AV valves open, SL valves closed
• atria contract and pump blood
• additional 10–40% filling of ventricles - isovolumic ventricular contraction: SYSTOLE, AV valves closed (LUB), SL valves closed
• ventricular myocytes begin to contract
• ventricle volume unchanged - ventricular ejection: SYSTOLE, AV valves closed, SL valves open
• ventricles fully contract
• pump blood to rest of body - Isovolumic ventricular relaxation: DIASTOLE, AV valves closed, SL valves closed (DUB)
• ventricles relax
• ventricle volume unchanged
• atria expand and are filling
What is hypertension?
What is normal BP, prehypertension, stage 1 hyper tension, and stage 2 hypertension?
- is consistent elevation of systemic arterial blood pressure
- what is normal blood pressure and what is elevated? depends on age, gender, systolic/diastolic
What are the categories of hypertension?
- primary (essential hypertension)
- secondary hypertension
- malignant hypertention
primary (essential hypertension)
- a chronic elevation in BP that occurs without any evidence of other disease
secondary hypertension
- a chronic elevation of BP that results from some other disorder, such as kidney disease, hormonal disorder, coarctation of the aorta
malignant hypertension
- Sudden increase in BP – diastolic >120