2. Circuits- Exam 1 Flashcards
define neonatal and pediatric in regards to age
Neonatal: < 30 days
Pediatric: up to 18 yo (< 18)
Pediatric patients are ___ small adults
NOT
Neonates have higher or lower metabolic demands
higher
Neonates have immature myocardium. When does it mature and what is the immature myocardium prone to?
matures 3-12 months
Immature myocardium prone to “stretch injury”
Neonates utilize what for of energy consumption
glucose oxidation
What form of blood gas management do neonates utilize?
Utilize alpha-stat and pH-stat blood gas management
Adults utilize what for energy consumption?
fatty acid dependent
What form of blood gas management do adults utilize
Utilize mostly alpha-stat and some pH-stat blood gas management
<10 kg= _____ cc/kg blood volume
85 cc/kg
11-20 kg= _____ cc/kg blood volume
80 cc/kg
21-30 kg= _____ cc/kg blood volume
75 cc/kg
31-40 kg= _____ cc/kg blood volume
70 cc/kg
> 40 kg= _____ cc/kg blood volume
65 cc/kg
Circuits fitting for Neonatal Pack
3/16” x ¼”
Circuits fitting for Infant Pack
¼” x ¼”
Circuits fitting for Pediatric Pack
¼” x 3/8”
Circuits fitting for Small Adult Pack
3/8” x 3/8”
Circuits fitting for Adult Pack
3/8” x ½”
What are the 9 steps to building a Peds circuit
It is Imperative to ascertain kg weight prior to choosing
- Determine BSA (kg weight may suffice)
- Determine max flow rate (KG weight or BSA based)
- Choose appropriate pump boot
- Pick arterial cannula
- Determine arterial line size
- Pick venous cannula
- Determine venous line size
- Choose oxygenator
- Choose arterial filter
0-3 kg= ______ Flow (cc/kg/min)
200 cc/kg/min
3-10 kg= ______ Flow (cc/kg/min)
150 cc/kg/min
10-15 kg= ______ Flow (cc/kg/min)
125 cc/kg/min
15-30 kg= ______ Flow (cc/kg/min)
100 cc/kg/min
> 30 kg= ______ Flow (cc/kg/min)
75 cc/kg/min
> 55 kg= ______ Flow (cc/kg/min)
65 cc/kg/min
Formula to determine max flow
Weight * flow for that group
EX: (5.3kg*150cc/kg/min= 795 cc/min or 0.795 L/min)
Boot diameter of 3/16”= ______ stroke vol/revolution and ______ max RPM’s
7 cc
700 rpm
Boot diameter of ¼””= ______ stroke vol/revolution and ______ max RPM’s
13 cc
1300 rpm
Boot diameter of 3/8”= ______ stroke vol/revolution and ______ max RPM’s
27 cc
2700 rpm
Boot diameter of ½””= ______ stroke vol/revolution and ______ max RPM’s
45 cc
4500 rpm
Ohms law and its hydraulic analogy?
VIR
PQR
Reynolds Number= [formula]
(VelocityDensityDiameter) / Viscosity
Poiseuilles Law= [formula]
Flow = (ΔP x πr4) / (Length x Viscosity x 8)
Reynolds number for blood flow is
2000
When selecting a cannula, what do you look for?
Look for high flow – low pressure drops
What type of cannula give us good flow with a lower pressure drop?
Thin walled reinforced and thin wall metal cannula
It’s all about the __(for us) and the __ (for surgeons)
It’s all about the ID (for us) and the OD (for surgeons)
When selecting an arterial cannula, what is the goal
utilize the smallest cannula w/ the highest flow rate
When selecting an venous cannula, what is the goal
drain the patient with the smallest cannulas
Do not exceed a pressure drop of ____ for arterial cannulas
> 100 mmHg
Do not exceed a pressure drop of ____ for venous cannulas
-30 to -40 range
For arterial cannula’s, when is critical velocity reached?
- when laminar flow becomes turbulent (Reynolds #)
- Higher pressures = higher sheer stress = hemolysis = bad
Vacuum Assist Venous Drainage (VAVD) may help but at what cost
micro-emboli
When selecting the arterial cannula, what should you anticipate?
Anticipate larger flow needs when warming
Anticipate viscosity changes
If given a french size, how do you convert to ml
divide by 3
What is the #1 type of arterial peds cannula
DLP wire reinforced
DLP wire reinforced cannula:
8F= _____ max flow at 100mmHg press gradient
750 ml/min
DLP wire reinforced cannula:
10F= _____ max flow at 100mmHg press gradient
1300 ml/min
DLP wire reinforced cannula:
12F= _____ max flow at 100mmHg press gradient
2200 ml/min
DLP wire reinforced cannula:
14F= _____ max flow at 100mmHg press gradient
2900 ml/min
DLP wire reinforced cannula:
16F= _____ max flow at 100mmHg press gradient
4000 ml/min
A tubing diameter of 1/8= ____ max flow with a prime volume of ___
Max arterial flow= 700 ml/min
Prime volume= 2.5 ml/ft
A tubing diameter of 3/16= ____ max flow with a prime volume of ___
Max arterial flow= 1100 ml/min
Prime volume= 7 ml/ft
A tubing diameter of 1/4= ____ max flow with a prime volume of ___
Max arterial flow= 2000 ml/min
Prime volume= 9.65 ml/ft
A tubing diameter of 3/8= ____ max flow with a prime volume of ___
Max arterial flow= 6500 ml/min
Prime volume= 21.7 ml/ft
A tubing diameter of 1/2= ____ max flow with a prime volume of ___
Max arterial flow= ——-
Prime volume= 38.6 ml/ft
When determining venous cannulas, what 2 do we utilize?
Bicaval or Single Atrial
When determining venous cannulas, what should we anticipate?
Anticipate larger flow needs when warming
Anticipate viscosity changes
If you double the length of the cannula, what happens
blood flow is cut in ½
If you double the viscosity within the cannula, what happens?
blood flow is cut in ½
Whats the big difference between Bicaval or Single Atrial venous cannulas
Bicaval= you get 66% return from the IVC ans 33% SVC
Single Atrial= you get 100% from the RA
What is hold-up volume
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. As your viscosity goes up - so may your holdup volume
Terumo Capiox Baby RX05: Max flow____ Prime Vol ____
Max Flow= 1.5 L/m
Prime Vol= 43 cc
Medos Hilite 1000: Max flow____ Prime Vol ____
Max Flow= 1.0 L/m
Prime Vol= 57 cc
Sorin Kids D100: Max flow____ Prime Vol ____
Max Flow= 0.7 L/m
Prime Vol= 31 cc
What are your choices for ped ALF?
Terumo AFX02
Medtronic affinity
Integral oxygenator filtration
What are the 9 basic prime constituents for peds?
Normosol Solumedrol (methylprednisolone) Antibiotic 25% Albumin Mannitol CaCl NaHCO3 PRBC’s Heparin 100 units
describe 25% Albumin (5 things)
- Large molecule
- Aids passification of tubing
- Elevates C.O.P. and serum osmolarity
- Good osmotic “pull” from tissues (1.3:1)
- Be careful in recommendations (i.e X-coating calls for wetting with crystalloid 1st)
Antibiotic dosage: Cefazolin (Kefzol, Ancef)
25 mg/kg (max dose = 1 g)
Antibiotic dosage: Ampicillin
50 mg/kg (max dose = 1 g)
Antibiotic dosage: Gentamicin
2 mg/kg (max dose = 80 mg)
Antibiotic dosage: Nafcillin
25 mg/kg (max dose = 1 g)
Antibiotic dosage: Vancomycin
10 -15 mg/kg (max dose = 1 g)
What is special about vancomycin?
Vancomycin is titrated during CPB. All other of the antibiotics listed can be safely administered to the extra-corporeal circuit prior to the intiation of CPB.
The pump prime may contain ___ mg/kg methylprednisolone (up to ___ mg) on ALL patients undergoing procedures requiring CPB.
30 mg/kg
500 mg
Pediatric transplant patients receive ___ mg/kg methylprednisolone when the aortic crossclamp is released
30 mg/kg
The prime should have a bicarbonate concentration of approximately __ mEq/L
24 mEq/L
The amount of NaHCO3 necessary for a given amount of asanguineous volume may be calculated using what formula?
? mEq NaHCO3 = 0.025 * mL asanguineous volume
If PRBC’s are added to the prime, then a sample should be taken, and NaHCO3 administered according to the following formula
? mEq NaHCO3 = 0.3(kg wt)(BE)
describe mannitol (4 things)
Osmotic dieuretic
Elevates Osmolarity rapidly
Given over a range of medical disciplines
Oxygen radical scavenger
How much mannitol os given in the prime? How much is given during AoXc removal?
0.25 g/kg in the prime
An additional 0.25 g/kg is given during AoXc removal
Since mannitol is 25% solution, how do you determine the dose?
The amount of kg of the pt is the amount of ml’s of mannitol (EX 5.3 kg= 5.3 ml of mannitol)
CaCl2 is not routinely added to the prime. However, an ionized Ca++ level of the perfusate should be measured shortly after the initiation of CPB and corrected upward to ____ mM/L, if necessary
- 7 - 0.8 mM/L
- -This is imperative because a level of 0.7 to 0.8 mM/l would allow the appropriate level to be present in the cardioplegia solution of a standard 4:1 solution
For neonates/infants < 5kg, ___ ml PRBC’s are added to the prime to avoid what?
100 ml
to avoid a prolonged period a asanguineous perfusion
Always keep an idea of where your hematocrit will be:
CPB Hct = [formula]
(((IVBV x kg x (patient Hct / 100)) / ((IVBV x kg) + mL prime))) x 100