test 8

Question 1

Crystalloid solutions helped with

Answer 1

• serum electrolyte stable
• minimal metabolic acidosis
• decreased red blood cell damage
• minimal post operative pulmonary problems
• no renal problems
• fluid retention

Question 2

relationship between shear stress, shear rate, and viscosity

Answer 2

Shear Stress/Shear Rate = Viscosity

Question 3

vascular resistance

Answer 3

(8L/(Pi)r^4)

Question 4

What happens when you go on bypass and run lower than normal blood flow?

Answer 4

 Decreased flow
 Decreased shear rate
 Increased viscosity
 Increased vascular resistance
 Further decrease in flow through tissue

Question 5

What happens when you are on bypass and start to cool the patient?

Answer 5

 Increased viscosity
 Increased vascular resistance
 Further decrease in flow through tissue

Question 6

Decrease in perfusion pressure does what

Answer 6

 decreased viscosity
 change in baroreceptor perception of pressure
 dilution of circulating catecholamines (diluting out epi and norepi)

Question 7

Decrease in sludging – counteract affect of hypothermia

Answer 7

 increase in venous return

 increase in flow through various organs

Question 8

Decrease in post-pump / post-op complications in

Answer 8

 cerebral
 pulmonary
 renal

Question 9

Affects of hemodilution

Answer 9

 Decrease in perfusion pressure
 Decrease in sludging – counteract affect of hypothermia
 Decrease in post-pump / post-op complications
 Decrease in oxygen carrying capacity
 Decrease in colloid oncotic pressure
 Change drug pharmacokinetics & pharmacodynamics

Question 10

Benefits of hemodilution

Answer 10

 Decreased exposure to homologous blood products
 Decreased blood viscosity
 Improved regional blood flow
 Improved oxygen delivery to tissue
 Improved blood flow at lower perfusion
pressures

Question 11

HCT

Answer 11

 <15% - maldistribution of coronary blood flow
 >34% - increased risk of MI
 Acceptable range – 16 to 33%
 Optimal range – 23 to 27%

Question 12

factors affecting fluid shift

Answer 12

 Temperature
 Pump flow rate
 Urine output
 Adequacy of venous drainage
 Plasma colloid oncotic pressure
 Interstitial fluid pressure
 Hemodilution***
 Duration of bypass
 Type of cardiac disease

Question 13

hemodilution reversal

Answer 13

 Diuresis
 Ultrafiltration
 Hemodialysis

Question 14

how temperature affects solubility

Answer 14

solubility inversely proportional to temperature

Question 15

acceptable gradient between water and blood

Answer 15

6-10 degrees

Question 16

heat capacity

Answer 16

AMOUNT OF HEAT REQUIRED TO RAISE IT’S

TEMPERATURE BY 1°C

Question 17

specific heat

Answer 17

HEAT CAPACITY OF 1GRAM OF A SUBSTANCE

Question 18

how much heat is lost or gained

Answer 18

dQ = c m dT

Question 19

How much heat is lost/gained per minute

Answer 19

Heat Flow = Q/t = c BF p dT

Question 20

Factors Influencing Efficiency and Rate of Heat Transfer

Answer 20

 H-E material
 Thickness of heat
conductor
 Thermal conductance in
cal/sec/cm/°C
 Heat loss
 Priming volume
 Blood path thickness
 Blood and water path
resistance
 Water flow variation
 H-E efficiency-design

Question 21

Fourier’s Law of Heat Flow

Answer 21

Rate of heat transfer between water and blood is proportional to:
 the temperature gradient
 the amount of surface area available for transfer
 the ability of the material to transfer heat

Question 22

Coefficient of Heat Exchange

Answer 22

Tbo – Tbi
CHE = —————–
Twi – Tbi

Question 23

Increase heat flow via

Answer 23

 Counter current flow
 Creating chevrons to promote mixing and larger surface area
 Minimizing thickness without sacrificing integrity
 Increase time in pathway