``` estimating blood volumes: Weight (kg): 40 ```

``` Blood volume (cc/kg) 40 = 65 - used for calculating post dilutional hematocrit ```

- total volume that flows through a tube Flow = (change in pressure x pi x radius^4) / (length of tube x viscosity of fluid x 8) - radius is the only thing that changes

test 1 part 2 Flashcards by Marcus Chlopek

Neonates and pediatric overview

 Many pediatric organ systems are immature / vulnerable
 Neonates have higher metabolic demands
 Neonates have IMMATURE MYOCARDIUM (matures 3-12 months)
 Neonates utilize GLUCOSE OXIDATION
 Immature myocardium prone to “stretch injury”
 Utilize alpha-stat and pH-stat blood gas management

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adults overview

 Adult circuits tend to be “one size fits all”
 Many adult organ systems have acquired disease
 Some organ systems have failed
 Adults utilize FATTY ACID DEPENDENT energy source
 Not affected as much by prime volume dilution
 Mature clotting cascade and organ systems
 Utilize mostly alpha-stat and some pH-stat blood gas management

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estimating blood volumes:
Weight (kg):
<10
11-20
21-30
31-40
>40

Blood volume (cc/kg)
< 10 = 85
11-20 = 80
21-30 = 75
31-40 = 70
> 40 = 65
- used for calculating post dilutional hematocrit

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Circuits are commonly called:
3/16” x ¼”
¼” x ¼” 
¼” x 3/8” 
3/8” x 3/8”
3/8” x ½”

 3/16” x ¼” = Neonatal Pack
 ¼” x ¼” = Infant Pack
 ¼” x 3/8” = Pediatric/Small Adult Pack
 3/8” x 3/8” = Adult Pack
 3/8” x ½” = Large Adult Pack

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Sequence to choosing an appropriate pediatric CPB circuit

Determine BSA (kg weight may suffice)
Determine maximum flow rate (KG weight based or BSA based)
Choose oxygenator
4.Choose appropriate pump boot
Determine arterial line size
Determine venous line size
 *Packs (1/8” x 3/16”, 3/16”x3/16”, 3/16”x¼”, ¼” x ¼”, ¼”x3/8”, 3/8”x3/8”, 3/8”x½”)
Pick arterial cannula
Pick venous cannula

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Kg weight - based flows
Weight (kg)
0-3
3-10
10-15 
15-30
>30
>55

 0-3 = 200 cc/kg
 3-10 = 150 cc/kg
 10-15 = 125 cc/kg
 15-30 = 100 cc/kg
 >30 = 75 cc/kg
 >55 = 65 cc/kg

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Terumo Baby RX05 (Max Flow and Prime volume)

Max Flow: 1.5 L/min (in red)

Prime volume: 43 cc (in red)

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Terumo RX10

Max Flow: 4 L/min
Prime volume: 135 cc
-used for bigger kids

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Terumo RX15

Max Flow: 5 L/min
Prime volume: 135 cc
-used for bigger kids

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Sorin Kids D100

Max Flow: 0.7 L/min

Prime volume: 31 cc (in red)

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Sorin Kids D101

Max Flow: 2.5 L/min

Prime volume: 87 cc

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Stroke volume/ revolution for boot diameter:
3/16”
¼”
3/8”
½”

 3/16” = 7 cc
 ¼” = 13 cc
 3/8” = 27 cc
 ½” = 45 cc

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do NOT exceed how many RPM’s for maximum tubing flows

100 RPM’s

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Max tubing flows for:
3/16”
¼”
3/8”
½”

 3/16” 7 cc => (x 100 =700 cc)
 ¼” 13 cc => (x 100= 1300 cc)
 3/8” 27 cc => (x 100= 2700 cc)
 ½” 45 cc => (x 100= 4500 cc)

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Reynolds number

Reynolds number = (velocity of fluid x density of fluid x diameter of pipe) / viscosity of fluid

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Poisueille’s law

total volume that flows through a tube
Flow = (change in pressure x pi x radius^4) / (length of tube x viscosity of fluid x 8)
radius is the only thing that changes

how does turbulent flow effect the critical velocity

Turbulence decreases flow at any given perfusion pressure
turbulence increases the perfusion pressure required for a given flow
there is a “critical reynolds number” that when it is exceeded, there is a difference between turbulent flow and laminar flow

Choosing arterial tubing size base on max blood flow and how much prime it contains
1/8 
3/16”
¼”
3/8”

1/8 => 700 mls/min => 3 mls/ft
3/16 => 1100 mls/min => 7 mls/ft
1/4 => 2000 mls/min => 10 mls/ft
3/8 => 6500 mls/min => 20 mls/ft

why is venous line normally larger

need a bigger line to drain more

Choosing arterial tubing size base on max blood flow and how much prime it contains
3/16”
¼”
3/8”
½”

3/16 => 1100 mls/min => 7 mls/ft
1/4 => 2000 mls/min => 10 mls/ft
3/8 => 6500 mls/min => 20 mls/ft
½ = > ———- => 40 mls/ft

Resistance in the venous reservoir

We will not be dealing with a wide open venous line
Resistance in your reservoir can be a factor in venous return
◦ Since your venous line goes into the sock, a certain amount of volume is “delayed” there
◦ This is called “holdup volume”
◦ As your viscosity goes up - so may your holdup volume

Pediatric Cannula Selection

Cannulation can be achieved in various vessels depending on the anomaly
Look for high flow – low pressure drops
Thin walled reinforced and thin wall metal cannula give good flow with lower pressure drops
It’s all about the ID (inner diameter) (for us) and the OD (outer diameter) (for surgeons)

Pediatric Cannula Selection: arterial

 Aim: utilize the smallest cannula w/ the highest flow rate
 Do NOT exceed pressure drop > 100 mmHg
 Critical velocity is reached when laminar flow becomes turbulent (Reynolds #)
 Higher pressures = higher sheer stress = hemolysis = bad

Pediatric Cannula Selection: venous

 Aim: drain the patient with the smallest cannulas
 Be aware if the cannulation is bicaval or single atrial cannula
 Pressure drop is in the -30 to -40 range (pressure-flow curve)
 Vacuum Assist Venous Drainage (VAVD) may help but at a cost (micro-emboli may be associated with VAVD)

Determining arterial cannula

 Determine max flow:  Cannulation may be aortic / femoral / neck  Pressure drop should not exceed 100 mmHg  Anticipate larger flow needs when warming  Anticipate viscosity changes

Main ascending aortic cannulae

DLP wire reinforced

main femoral arterial cannulae

Biomedicus arterial cannulae

Determining venous cannula

 Determine max flow  Cannulation utilizes Bicaval or Single Atrial  Pressure drop -30 to -40 mmHg  ( MEASURE IT - its gravity!)  Anticipate larger flow needs when warming  Anticipate viscosity changes

when choosing a cannula, it's all about what

- resitance

priming with 25% albumin

- Start with prime then take out the filter and put in your albumin. displace all of the prime and all that is left in there is pretty much albumin  Aids passification of tubing  Elevates C.O.P. and serum osmolarity  Good osmotic “pull” from tissues - make sure tubing isn't coated with X-coating which calls for priming with crystalloid first

Cefazolin (Kefzol, Ancef) dose

 25 mg/kg (max dose = 1 g)

Pump prime may contain how much solumedrol (methylprednixolone)

30 mg/kg up to 500mg

bicarbonate equation

0.3(kg wt)(BE) = NaHCO3 mEq

Mannitol calculation

0.25 g/kg in prime

CaCl

 If priming with blood, a good rule of thumb is to use 1 mg CaCl per 1 mL of blood product

for neonates/infants < 5kg

- 100 ml PRBC’s are added to the prime to avoid a prolonged period a asanguineous perfusion.

calculate the PDHCT

- practice

hemochron vs hepcon (ACT)

- hemochron gives you abnormally high values compared to the hepcon - could result in having clotting problems in the circuit

Platelet works

 Assesses platelet function and compares functional and nonfunctional platelets by percentage (%) - does not tell you a platelet count