Hemodynamic Disorders

Question 1

What is the definition of shock?

Answer 1

State of systemic tissue hypoperfusion due to reduced cardiac output and/or reduced effective circulating blood volume

Question 2

What are the major categories of shock?

What are some examples of disorders/diseases/traumas that cause each kind of shock?

What are the mechanisms of causing shock for each category?

Answer 2

Cardiogenic

Hypovolemic

Systemic inflammatory responses

Question 3

Shock of any form can lead to […] if not corrected

Answer 3

Hypoxic tissue injury and death

Question 4

Describe the relationship between Mean arterial pressure, CO and TPR?

What does this relationship have to do with shock?

Answer 4

MAP = CO x TPR

If MAP decreases, can lead to shock…therefore decreases in CO or TPR has the potential to induce shock

Question 5

What is the relationship between stroke volume, heart rate and cardiac output?

What is the relationship of these things to shock?

Answer 5

CO = SV x HR

Decrease in CO leads to decrease in MAP, which can lead to shock. Since CO is dependent on SV and HR, decrease in these can also lead to shock.

Question 6

What are the 3 stages of shock?

Answer 6

Question 7

What is trauma induced coagulopathy?

Answer 7

Question 8

What is pulse pressure?

What may narrowed PP indicate?

Answer 8

Difference between systolic and diastolic BP

Shock (narrow = low which is < 25% of systolic BP)

Question 9

What are the signs/symptoms of shock?

Answer 9

Hypotension

Tachycardia

Oliguria

Abnormal mental status

Tachypnea

Cool, clammy, cyanotic skin

Metabolic acidosis

Hyperlactatemia

Diaphoresis

Question 10

What is the lethal triad (refers specifically to trauma)?

Answer 10

• Hypothermia –> reduced metabolic activity combined with cool environments in hospital, cool fluids being given –> reduce core temp –> platelet dysregulation and impaired enzymatic function
• Coagulopathy
• Acidosis
  
  • Poor tissue perfusion –> shift to anaerobic metabolism –> build up of lactate –> rapidly converted to lactic acid –> coagulation dysregulation by interfering with the assembly of coagulation factor complexes involving calcium and negatively charged phospholipids

Question 11

Hemmorhagic Shock

• How is it initially treated?
• How much does infusion raise hct and hb?
• What would you give the person if there was known or strongly suspected coagulation abnormalities?
• In what ratio do you give plasma and platelets to units of packed red blood cells?

Answer 11

• Packed red blood cell transfusion as long as Hb is < 7% and/or pt lost > 30% blood volume
• hct = 3%, hb = 1g/dL
• Plasma
• 6 units plasma and 1 unit platelets for every 6 units RBCs

Question 12

Why do transfused blood products have to have citrate in them? Why can this cause issues when transfused? How are these issues overcome?

Answer 12

• In the normal clotting cascade, exposure to Ca++ will hold factor 7A and tissue factor together leading to coagulation. Citrate is put in the donated blood to prevent clotting before use in a donor.
• Once transfused, it’s possible that the person may not have a well enough functioning liver (esp in shock) to metabolize citrate, thus the treatment can induce hypocalcemia and progressive coagulation dysfunction since Ca++ can’t dissociate from citrate to initiate coagulation.
• IV calcium chloride is given after 4 units of blood to help clotting occur

Question 13

Ischemia leads to a shift from […] metabolism to […] metabolism which results in an influx of […] (3 things) into the cell and an efflux of […] (1 thing) out of the cell.

Answer 13

Aerobic

Anaerobic

Na+/Ca++/Water

K+