Hemodynamic Lectures

Question 1

Define hemodynamic disorder

Answer 1

Cellular well being and organ function depend critically on an intact circulatory system to deliver oxygen and nutrients as well as remove CO2 and metabolic wastes
- Generally produced by abnormalities in blood supply or fluid balance

Question 2

What are 8 major disturbance?

Answer 2

Edema
Vascular congestion
Hemorrhage
Thrombosis
Embolism
Hyperemia
Infarction
Shock

Question 3

Define Edema

Answer 3

Increased fluid accumulation

Question 4

Excess fluid can be what?

Answer 4

Intracellular or extracellular
Generalized or localized
- It is referred to by location (hydroperitoneum, hydropericardium, hydrothorax)

Question 5

What causes edema?

Answer 5

Intracellular fluid accumulation often occurs in response pathologic cellular damage
- Very frequently, in the absence of cellular trauma or injury, the edema is extracellular and caused by circulatory imbalance, permeability changes or inflammation

Question 6

What are example of increased hydrostatic pressure as a cause of edema?

Answer 6

Impaired venous return (congestive heart failure)
Arteriolar Dilation (heart, neurohumoral dysregulation)

Question 7

What are example of reduced plasma osmotic pressure as a cause of edema?

Answer 7

protein-losing (nephrodtic syndrome, liver cirrhosis)

Question 8

What are example of lymphatic obstruction as a cause of edema?

Answer 8

Inflammation, neoplastic, postsurgical

Question 9

What are example of sodium retention as a cause of edema?

Answer 9

Excessive sodium intake (renal insufficiency) 
Increased reabsorption (renal hypoperfusion)

Question 10

What are example of inflammation as a cause of edema?

Answer 10

Alteration in vascular permeability

Question 11

What factors affect fluid balance across capillary walls?

Answer 11

Increased hydrostatic pressure or diminished plasma osmotic pressure leads to a net accumulation of extravascular fluid (edema)
- Increase in interstitial fluid pressure leads to tissue lyphatics removing the excess volume and returning it to the circulation

Question 12

What causes persistent tissue edema?

Answer 12

Exceeding the ability of the lymphatics to drain tissue

Question 13

Subcutaneous edema of the legs?

Answer 13

Feature of congestive heart failure (right ventricle)

Pitting Edema

Question 14

Define Pitting Edema

Answer 14

Pressure applied with the fingers to the edematous tissue will temporarily displace the fluid and leave a finger-shaped depression

Question 15

Edema due to renal dysfunction?

Answer 15

Affects most all parts of the body equally but may manifest initially in tissues with loose connective tissue such as the eyelids

Question 16

Define periorbital edema?

Answer 16

Edema in loose connective tissues

Question 17

Define pulmonary edema

Answer 17

Common feature of left ventricular failure, pulmonary infection or hypersensitivity reactions

Question 18

Define Brain edema

Answer 18

Can be caused by trauma, hypertensive crisis, or infection
Important because the brain is enclosed and tissue swelling can only occur by displacement of the vascular space or by compression

Question 19

Define Hyperemia

Answer 19

Caused by neurogenic mechanisms or the release of vasoactive substances

Question 20

Example of hyperemia?

Answer 20

Exercise induced increase in blood flow and blood volume in muscles due to arteriolar dilation (tissue becomes redder due to increased amount of oxygenated hemoglobin)
- Active process

Question 21

Define congestion

Answer 21

Results from impaired outflow of blood from tissue
Generalized (heart failure) or localized (local venous obstruction) –> tissue becomes blue-red color (cyanosis) from deoxygenated hemoglobin in blood
Congestion in capillary beds is frequently linked to development
- Passive process

Question 22

Chronic passive congestion may cause?

Answer 22

Capillary stasis
Hypoxia
Cellular degeneration
Capillary leakage of blood

Question 23

Define embolism

Answer 23

Detached intravascular solid, liquid, or gaseous mass that is carried by the blood to a site distant from its orgin
- When an embolus gets stuck in the blood vessel it causes a stroke or gangrene

Question 24

Define gangrene

Answer 24

Localized death and decomposition of body tissue because of obstructed circulation or bacteria

Question 25

Define thromboembolism

Answer 25

Eventually the embolus lodges in a small blood vessel resulting in a vascular occlusion, leading to ischemia and cell death
Effects depend on: pulmonary, systemic circulation and size of the vessel occluded

Question 26

Define pulmonary embolism

Answer 26

Where the embolus gets stuck in a vessel going to the lungs

• Pass through the heart and is pumped out of the pulmonary artery
• 60-80% of the cases are silent because they are small

Question 27

Large pulmonary embolism can produce?

Answer 27

Pulmonary hemorrhage, pulmonary hypertension, cardiovascular collapse, and sudden death due to right heart failure

Question 28

Define pulmonary thromboembolism

Answer 28

Large embolus derived from a lower extremity deep venous thrombosis and now impacted in a pulmonary artery branch
- Sudden death occurs when 60% or more of the pulmonary circulation is blocked

Question 29

Where do systemic embolism that travel in the arterial circulation go?

Answer 29

75% go to the lower extremities
10% go to the brain
15% go to all other organs combined (kidney, spleen, upper extremities)

Question 30

What are the consequences depending on the affected tissues?

Answer 30

Vulnerability to ischemia
Size of the occluded blood vessel
Extent of the tissue’s collateral blood supply

Question 31

Most systemic embolism’s arise from what?

Answer 31

Intracardiac mural emboli

Question 32

Define air/gas embolism

Answer 32

Caused by gas bubbles within the circulation obstructing vascular flow and causing ischemia
- More than 100 cc are required to have an clinical significance

Question 33

How may air enter the circulation?

Answer 33

During obstetric procedures
Due to chest wall injury
Complication of scuba diving
Mechanical positive-pressure ventilatory support
Hyperbaric oxygen therapy

Question 34

Define decompression sickness

Answer 34

Form of air embolism caused by sudden changes in atmospheric pressure
- Usually in deep-sea divers who spend long periods under increase atmospheric pressure

Question 35

How does decompression sickness occur in divers?

Answer 35

Large amounts of oxygen and other gases dissolve in the blood and tissue fluids
- Once too rapid ascent begins, the dissolved gases come out of solution and form minute bubbles in the bloodstream and tissues

Question 36

Define embolism

Answer 36

Occurs as a result of microscopic fat globules
Bone marrow embolus in the pulmonary circulation
- Cleared vacuoles represent marrow fat that is now impacted in a distal vessel along with the cellular hematopoietic precursors

Question 37

What is the pathogenesis involves?

Answer 37

Mechanical obstruction by micro-emboli of neutral fat
Subsequent toxic injury of the endothelium by free fatty acid
Result in local platelet and erythrocyte aggregation and granulocyte recruitment

Question 38

Define amniotic fluid embolism

Answer 38

Caused by amniotic fluid infusion into the maternal circulation

• Thrombogenic substances will be released from the amniotic fluid to pulmonary microcirculation
• Cause seizures and coma, if survive initial crisis –> edema occurs

Question 39

What is amniotic fluid embolisms characterized by the presence of?

Answer 39

Fetal squamous cells from fetal skin
Mucin from the fetal respiratory or GI tract
Lanugo hair
Vernix caseosa fat