Circuits and Components Flashcards
What 3 pressures do you measure in an ECMO circuit
pre oxygenator pressure
post oxygenator pressure
venous inlet (negative pressure)
better bladder – talk about it
the venous “reservoir” of an ECMO circuit
a ridged exterior tube with an inner cylastic membrane - outflow is connected to a roller pump, can keep the inner cylastic membrane expanded will create negative pressure sucking blood from the pts atrium (kinda like a centrifugal pump)
you keep a pressure manometer on that outer membrane, “bladder pressure (negative inlet pressure)” set the point to right before cavitation.
how does drainage work with ECMO?
kinetic assisted venous drainage, siphoning it out
what shunt may be in the ECMO circuit
an arterial venous shunt, with a CDI usually unit
arterial - high pressure
venous - low pressure
Never use what kind of caps in an ECMO circuit?
vented caps for transducers, bc they can suck air into the circuit easily
Where do you put heparin in, in an ECMO circuit?
pre oxygenator, to avoid clots in the oxygenator.
not before the centrifugal pump bc it can have too much negative pressure and suck in the whole syringe of heparin on accident
neonates - the majority of places still do heparinize for ECMO
use an ACT test 160-220sec
What ACTs are you looking for on ECMO?
160 (180)-220 sec
Where do you put the flow probe on an ECMO circuit?
After the bridge before the patient so you are totally sure that flow is going to the patient
whats the protocol for the bridge in the ECMO circuit?
you keep it clamped the whole time you are on ECMO
who ever is sitting ECMO will have to unclamp and clamp the bridge every 7 minutes to ensure no clots are forming.
sometimes there is a bridge made with two male-male stopcocks filled with saline and you dont have to unclamp all the time. but if you want to test if the patient is ready to come off of ECMO you open them up.
3 cannula selection types for ECMO?
Arterial
Venous
Dual Lumen (V-V Cannula)
0-3 flow?
200 cc/kg
3-10kg flow?
150 cc/kg
10-15 kg flow?
125 cc/kg
15-30 kg flow?
100 cc/kg
> 30 kg flow?
75 cc/kg
> 55 kg flow?
65 cc/kg
Will you use vacuum is ECMO?
NO
If you pressurize the VR in a normal CPB circuit with vacuum - what happens?
the venous line is the least compilable so if the VR is over pressurized the pressure will shoot everything right up the venous line directly into the RA
make sure the relief pop-off valve is OPEN
V-A ECMO
Neonate cc/kg/min??
100-150 cc/kg/min
V-A ECMO
Ped cc/kg/min?
75-100 cc/kg/min
V-A ECMO
Adult cc/kg/min?
50-75 cc/kg/min
V-V ECMO
Neonate cc/kg/min??
100-120 cc/kg/min
V-V ECMO
Ped cc/kg/min?
90-100 cc/kg/min
V-V ECMO
Adult cc/kg/min?
75-90 cc/kg/min
Cannulation choices – Flow with Pediatric is what related?
weight related (cc/kg)
Have a large enough venous cannula to gravity drain the amount of blood flow that is required (but small enough to fit)
Cannulation choices – Flow with Adults is related to what?
usually indexed (L/min/m2)
Have a large enough venous cannula to gravity drain the amount of blood flow that is required (but small enough to fit)
Arterial ECMO cannulation
aim?
critical velocity of pressure drop????
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
Avalon V-V ECMO
MOST used cannula?
4-5 LPM
31 FRENCH
Venous ECMO cannula
aim?
pressure drop?
Aim: drain the patient with the smallest cannula
Be aware of the cannulation site
Pressure drop is in the -30 to -40 range
Veno-Arterial PEDS ECMO (V-A) cannulation sites?
Right Internal Jugular Vein
Right Common Carotid
Veno-Venous PED ECMO (V-V) cannulation sites?
Internal Jugular Vein alone
Veno-Arterial Adults ECMO (V-A) cannulation sites?
Femoral Venous
Femoral Arterial
Veno-Venous Adults ECMO (V-V) cannulation sites?
Femoral Venous
Jugular Venous
What is the tubing in an ECMO race way made of?
Super Tygon Tubing
The race way is about 5 feet long so that you can walk the race every 5-7 days so the tubing in the raceway when it is getting worn out you can just move it down
The Origen V-V Cannula
12 Fr for children what wt?
2-5 Kg
The Origen V-V Cannula
15 Fr for children what wt?
4-8 Kg
The Origen V-V Cannula
18 Fr for children what wt?
7-12 Kg
Veno-Venous ECMO
Venous blood is drained through what and arterialized blood returned where? (special kind of cannula)
through a single lumen of a double lumen cannula
Arterialized blood is returned via the other lumen
V-V Canuula Size and ?Patient Weight Range
?F 2-5 kg
?F 4-8 kg
?F 7-12 kg
12F
15F
18F
Poiseuille’s Law:
= ΔP x π r4/L x V x 8 ΔP:pressure difference or gradient r:radius of tube L:length of tube V: viscosity of the fluid 8:constant of proportionality *If you double the length, blood flow is cut in ½ *If you double the viscosity, blood flow is cut in half
ECMO tubing
material?
standard sizes?
how do the sizes come?
PVC or Silicone, Special tubing (Super Tygon)
Standard sizes are ¼”, 3/8”, and ½”
Durometer-measure of the hardness of a material.
Hardness may be defined as a material’s resistance to permanent indentation.
Each has size x wall thickness (1/4” x 1/8” or ¼” x 3/32”)
Super Tygon Special tubing is formulated to do what?
is formulated to withstand pump boot stress in roller pumps
Can walk the raceway every 7 days,Minimizes spalation
Boot vs SV/Revolution 3/16” ?cc ¼” ?cc 3/8” ?cc ½” ?cc
7cc (x100 = 700cc MAZ) 13cc (x100=1300cc MAX) 27cc (x100=cc MAX) 45cc (x100-cc MAX) * Do NOT exceed 100 rpm’s for maximum tubing flows
Going on ECMO?
A-B-V
unclamp arterial, move it to the bridge, unclamp venous
Coming off ECMO?
V-B-A (very bad accident)
clamp venous, unclamp bridge use that clamp to clamp the arterial line
Kids can get inter-cranial bleeds when in what oxygen state?
hypoxic
acidosis —> inter-cranial bleeding —>strokes
Can any oxygenator work for ECMO?
Any oxygenator will suffice for off label use
Blood outside-Gas inside the fiber bundle
Quadrox Adult Specifications BF rate? total prime volume? SA? material oxygen membrane?
0.5-7 LPM
250ml
1.8m2
polymethylpentene
The ECMO bridge?
The bridge serves to prevent the ECMO circuit from being static when it is necessary to come off ECMO for a period of time
Consider it an A-V shunt
Can be done with 2 stopcocks and 1/8” tubing open when needed and reflush with saline
you’ll see–
No bridge
¼” and 3/8” bridge
Luer lock 1/8” bridge
ECMO monitoring?
Arterial Blood gases
Venous Blood gases
Venous Saturations
Cerebral Oximetry
NIRS on ECMO?
nanometers?
Near-infrared spectroscopy (NIRS) technology, such as that used in pulse oximetry, has been used and trusted in the world of medicine for decades.
Near-infrared spectroscopy (NIRS) is a spectroscopic method that uses the near-infrared region of the electromagnetic spectrum
(from about 800 nm to 2500 nm)
