ECMO Physiology / Midterm Exam Flashcards
VA ECMO Cannulation ?
– Right Internal Jugular
– Right Common Carotid
Goal or VA ECMO ?
80% of the cardiac output (80-100 ml/kg)
– Maintain pulsatile waveform (dampened)
Optimal pulse pressure for VA ECMO ?
10 - 15 mmHg
Anything that changes the volume status of the patient will change the ratio of pump to heart flow, such as ?
IV,
urine,
edema,
hemoconcentrator
How can we calculate the preload to the pump?
CVP = Bladder Pressure
On VA ECMO how can we monitor adequacy of perfusion?
SVO2
Adding volume would increase pulse pressure, so therefore what can we expect of the PaO2 ?
Drop
Removing volume would decrease our pulse pressure, so therefore what can we expect of the PaO2 ?
Increase
Reducing pump flow would increase our pulse pressure, therefore what can we expect of the PaO2 ?
decrease
Increasing pump flow would decrease our pulse pressure, therefore what can we expect of the PaO2 ?
Increase
VV ECMO Cannulation ?
– Withdraw from RA
– Return to RA
Goal of VV ECMO ?
- Increase blood O2 content
prior to lungs. - Dependent on heart for
patient circulation
What ECMO setup has has no effect on hemodynamics and the patient is dependent on heart for perfusion ?
VV ECMO
Wean from inotropes more slowly.
SvO2 monitors recirculation with what ECMO circuit?
VV-ECMO
Oxygen CAPACITY definition ?
The maximum amount of oxygen the blood is
capable of holding.
(Depends on Hct)
↓ Hct > ↓capacity > ↓ content > ↓ Delivery
Oxygen CONTENT definition ?
The amount of oxygen actually in the blood.
CaO2
Oxygen DELIVERY definition ?
The amount of oxygen provided to the cells.
Oxygen CONSUMPTION definition ?
The amount of oxygen removed from the blood
by the cells.
SvO2
What carries 98% of all
oxygen in the blood?
RBC
Hct that would reflect an anemic patient?
Plasma 72%
Blood 28%
Hct that would reflect an patient with Polycythemia?
Plasma 30%
Blood 70%
Hct that would reflect a normal patient ?
Plasma 55%
Blood 45%
Oxygen content CaO2 formula?
(Hb x 1.36 x SaO2)+(0.003 x PaO2)
[Bound]
1 g Hb (3% Hct) =
[Dissolved]
450 mmHg
Oxygen delivery DO2 formula =
CaO2 x CO
C.O. formula =
HR X SV
S.V. formula =
C.O. / HR
Oxygen Consumption VO2 formula ?
(DaO2 - DvO2) x C.O.
Normal newborn Arterial:
SAT 100%
PO2 =
PCO2 =
PO2 = 100 PCO2 = 40
Normal newborn Venous:
SAT 75%
PO2 =
PCO2 =
PO2 = 40 PCO2 = 45
Mixed Venous Oxygen
Saturation
SVO2 formula =
O2 delivered - O2 consumed
what does a decrease in SVO2 represent ?
indicates that the body
has called upon its last line of defense to
preserve O2 balance and intervention may
be appropriate.
What are the 3 different blood samples to evaluate on VA ECMO ?
– Venous (pre oxygenator)
– Post Oxygenator
– Patient Arterial (mixed arterial)
How would you evaluate Oxygenator function ?
Compare pre to post oxygenator blood gas
How would you evaluate overall patient support ?
Compare patient and
venous blood gases
How would you evaluate ECMO vs Patient contribution ?
– Compare Post and Patient
blood gases.
– Consider pump flow and
arterial pulsatility
Standing orders and parameters to maintain Hct ?
Maintain Hct > 40 %
– 10 ml/kg
Standing orders and parameters to maintain Platelets ?
Maintain Platelets > 100 K
– 1 unit for more than 20K below parameter
– 1/2 unit is less than 20 K below parameter
Standing orders and parameters to maintain fibrinogen ?
Maintain Fibrinogen >100 K
– 1 unit Cryoprecipitate (about 10 ml)
Standing orders and parameters to maintain Flow ?
Give 10 ml/kg to maintain flow
– Fluid to be determined
Unheparinized pts ACT normal values ?
90-120 sec
ECMO average ACT range ?
160-220 sec
based on patient
Uncomplicated TERM patient ECMO ACT range?
200-220 sec
Uncomplicated PRETERM patient ECMO ACT range?
180-200 sec
Surgical patient ECMO ACT range?
160-180 until hemostasis achieved, then increase parameter.
Heparin dose to cannulate ?
Heparin dose to initiate ?
- Bolus 100 u kg
- ACT > 200 sec
Heparin management as ACT begins to drop ?
- Start GTT (100u/ml)
- (monitor frequently)
50 u/kg/hr to start - Titrate GTT up and down to
maintain ACT
I’m having a hard time maintaining my ACT, what is the likely cause and what should I do about it?
- Platelets may decrease ACT, monitor frequently when administering Platelets.
- Bolus 1/2 previous hours dose
Diagnosing low bladder pressure on
(VA and V ECMO)?
• CVP