Week 2- Haemodynamic Dysfunction

Question 1

Define haemodynamics

Answer 1

the factors that govern blood flow

dependent upon the relationship between cardiac output, blood pressure and resistance

Question 2

What carries blood (oxygenated) to the rest o the body

Answer 2

Aorta

Question 3

How do we work out cardiac output

Answer 3

HR X SV

Stroke volume = diastole end volume of blood- systole end vol of blood.

Question 4

What can affect stroke volume

Answer 4

Venous return = pathological conditions (build up in vessels)
Exercise

Contraction= preload, calcium - thyroid disease of noradrenalin all affecting ca2+ (effecting hb) electrolyte imbalances.

Ejection= vascular resistance (clogged)

Question 5

What can affect hr

Answer 5

Parasympathetic - vagus nerve

Sympathetic

Question 6

What is an odema

Answer 6

Localised or generalised accumulation of fluid in interstitial space
Outside both the vascular fluid and cellular fluid compartments (in interstitium)

Question 7

Where can odema occur

Answer 7

 Hydrothorax: within thorax, around lungs; also pleural effusion

 Hydropericardium: Fluid in the pericardial sac

 Hydroperitoneum or ascites: Fluid in the peritoneal cavity

Question 8

What factors affect intravasvular and interstitial water movement

Answer 8

:
• Increased hydrostatic pressure: Impaired venous return i.e. DVT

• Reduced plasma osmotic pressure (hypo-proteinaemia): Liver cirrhosis,
nephrotic syndrome

• Lymphatic Obstruction: Trauma, fibrosis, neoplastic or post-surgical

• Sodium & Water Retention: Excessive salt intake with renal insufficiency

• Inflammation: Acute or chronic

• Decreased blood volume: Trauma

Question 9

When would fluid accumulate

Answer 9

When movement of water in tissues (or body cavities) exceeds lymphatic drainage

Question 10

List types of oedema

Answer 10

Pulmonary

Pitting

Renal

Periorbital

Lymphoedema (red and shiny skin)

Ascites (pregnant looking as in periteneum)

Hyperaemia ( red inflammation.)

Congestion (red or blue)

Question 11

Describe hyperaemia

Answer 11

Arteriolar dilation causes it

Red tissue due to engorgement of oxygenated blood

Question 12

Describe hyperaemia

Answer 12

Arteriolar dilation causes it

Red tissue due to engorgement of oxygenated blood

Question 13

Describe congestion

Answer 13

Passive process from impaired outflow of a tissue

Systemic - cardiac failure
Local congestion- isolated venous obstruction

Blue/ red colour
Deoxygenated hb in affected tissues
Reversible

Question 14

Compare hyperaemia to congestion

Answer 14

H= active process
C= passive

H= increase blood flow via vasodilation
C-= impaired blood flow

H= during exercise and in inflammation
C= venous obstruction and cardiac failure

H=oxygenated blood is redder
C- deoxygenated blood (cyanosed so blue)

Question 15

Describe left sided heart failure

Answer 15

Chronic congestion of the lung
Pulmonary congestion and oedema
Caused by aortic valve disease and primary myocardial disease

Feel weak
Not enough blood in body
Blue congestion
Very tired

Question 16

Describe right sided heart failure

Answer 16

Caused by left sided heart failure causing pulmonary congestion and raised pulmonary arterial pressure
Valve disease
Congenital heart disease

Congestion and oedema in feet ankles and sacrum

Swollen liver and spleen (liver hepotomegaly and spleen spleenomegal)

Too much blood not being processed by the heart
Shiny red and hot skin (hyperaemia)

Question 17

What is haemostasis

Answer 17

Process by which blood clots form at sites of injury

Question 18

Name 2 disorders of haemostasis

Answer 18

Haemorrhagic disorders- excess bleeding)

Thrombotic disorders- blood clots from within intact blood vessel or within heart)

Question 19

Describe haemostasis and clot formation

Answer 19

1. Vascular spasm (vasoconstriction)

Smooth muscles constrict when blood vessel is injured.
Helps limit blood loss

2. Platelet plug formation

Placements attracted to site of injury, adhere to exposes collagen (endothelial cells show when injured)
Platelets become activated upon contact with collagen and release chemical signals like ADP to recruit more platyeleyts
These platelets stick to each other causing a temporary plug which seals the wound.

3. Coagulation
   Enzymatic reactions leads to formation of fibrin mesh which stabilisates this plug forming a clot.
   Both intrinsic and extrinsic pathway converge at common pathway. Fibrin weave through placement plug
4. Clot retraction
   Clot undergoes retraction where it contracts nad brings the damage vessel walls closer together
   Platelets releases growth factors which stimulate repair of damages vessel
5. Clot removal
   Fibrinolysis occurs to dissolve clot. Plasmin breaks down fibrin mesh allowing normal blood flow.

Question 20

What is hypoxia

Answer 20

Lack of blood flow to an area

Question 21

What are the 3 primary causes for thrombus formation

Answer 21

1.endothelial injury
2. Stasis or slowing of the blood
3. Blood-hyper coaguliability

Question 22

Describe embolism

Answer 22

A mass that is carried by the blood to a site distal to point of origin.

Pulmonary Thrombo-embolism:
• 95% of venous emboli originate from deep leg vein thrombi.
1+ arteries in lungs become blocked by a blood clot

Systemic Thrombo-embolism:
Blood clot travels throug arterial circulation and blocks blood flow in other part of the body
• Emboli travelling within arterial circulation
• 80% arise from intra-cardiac mural thrombi
• 2/3rds associated with left ventricular wall infarcts
• The major sites for arteriolar embolism are lower extremities (75%) and the brain (10%)

Question 23

List types of embolism

Answer 23

Pulmonary Thrombo-embolism:
• 95% of venous emboli originate from deep leg vein thrombi.

Systemic Thrombo-embolism:
• Emboli travelling within arterial circulation
• 80% arise from intra-cardiac mural thrombi
• 2/3rds associated with left ventricular wall infarcts
• The major sites for arteriolar embolism are lower extremities (75%) and the brain

Fat Embolism
• Microscopic fat globules may be found in the circulation after fractures of the long bones
• Occurring in 90% of individuals with severe skeletal injuries
• Characterised by pulmonary insufficiency, dyspnoea, tachycardia, neurologic symptoms, anaemia

Air Embolism
• Gas bubbles within the circulation can obstruct vascular flow
• Enter circulation during obstetric procedures or as a consequence to chest wall injury

Amniotic Fluid Embolism
• Underlying cause is the infusion of amniotic fluid or foetal tissue into maternal circulation via a tear
in the placental membrane or rupture of the uterine veins.
• Characterised by a sudden sever dysp

Question 24

Describe infarction and factors affecting it

Answer 24

• An area of ischaemic necrosis caused by lack of blood supply by arterial supply or
venous drainage in a particular tissue.

• Nearly 99% of all infarcts result from thrombotic or embolic event and almost all
result from arterial occlusion.

Factors that affect the development of an infarction include:
1. Anatomy of the vascular supply
2. Rate of occlusion
3. Tissue vulnerability to hypoxia
4. Hypoxe

Question 25

Describe shock

Answer 25

Body’s tissues and organs do not receive enough blood flow and o2 leading to cell damage and organ failure

Cardiogenic shock= heart failure or function
Cardiomyopathy
Myocardinal infarction (heart attack) or heart valve disease

Question 26

What is another word for heart attack

Answer 26

Myocardial infarction