General Questions 2 Flashcards
Fluid removed during hemofiltration
Occurs due to pressure gradients
Heparin dosages may need to be altered when CVVH is added in the system because
The hemodiafilter absorbs all the heparin
The following are signs and symptoms of oxygenator failure
Increased pre membrane pressure, decreased oxygen and CO2 transfer, hematuria, blood leak from the gas egress
ECMO improves oxygen delivery by which mechanism
-Improving oxygen content through stabilization of hemoglobin saturations -improving oxygen content by taking over at least 60% of the blood flow through a functioning membrane lung, away from the sick native lung
-stabilzing oxygen delivery by taking over at least 60% of the cardiac output through the ECMO pump
Membrane failure can be characterized by a raising pump CO2 level because of the following
- changes in blood flow patterns caused by clot formation
- changes in sweep gas flow patterns caused by clot formation
- Alteration in membrane surface area caused by fibrin formation
- changes in oxygen concentration due to fibrin formation
Another ultimate goal of ECLS
To maximize oxygen delivery
What supplies do you take from the cannulation cart for an adult being cannulated for VA ECMO
Dilators (pikA, sorin dilators) venous and Arterial cannulas, reperfusion cannula (7” tubing and double male adapter, may need micro puncture introducer set), sterile instruments, typically size 0 suture (silk or prolene)
What supplies do you take from the cannulation cart for an adult being cannulated for VV ECMO
Dilators (venous dilators only), venous cannulas, sterile instruments, sutures
What is a reperfusion cannula? When is it used and why?
Low limb extremity to prevent ischemia. Only used for VV ECMO.
Define Cardiac Output
Amount of blood pumped by the heart in L/min
Define Cardiac index
CO/BSA = CI
Hemodynamic parameter that relates to the cardiac output from the left ventricle in one minute to the BSA
Define BSA
Body surface area
CO = HR x SV
For native cardiac function
CI = CO/BSA = SV x HR/BSA
CO = CI x BSA
Used to assess our ECMO flow
Define viscosity
How thick the blood is
How does viscosity affect ECMO flow
If the blood is thicker, it can decrease flows
Define Afterload
The amount of resistance that the heart has to overcome to open the aortic valve. On ECMO, the Afterload is the patient’s blood pressure or cannula size resistance
Define Preload
Volume of blood in the ventricle & your end diastolic pressure
Explain what increased Preload does to ECMO flow
It allows you to be able to flow more (negative pressure becomes less negative). Would not limit your ability to flow
Explain what decreased Preload does to the ECMO
On ECMO, Preload is determined by the amount of volume in the patient and can decrease flows if Preload is decreased
Explain how increased Afterload affects ECMO. Describe what you would see on the pressure monitor for the patient and what the cardiohelp would read
It would decrease your flows. The Arterial pressure would increase
Explain how decreased Afterload affects ECMO
It would increase your flows
What is the initial bolus of heparin for a 3.5 kg infant?
100 IU (bolus dose) x 3.5
350 IU
What is the bolus dose of heparin for a 100kg adult? 75kg adult?
10,000 IU
What is the priming volume for the Rotaflow pump?
32 ml
What is the priming volume for the Centrimag pump?
31 ml
Oxygen content = (______ x 1.34 x ______) + (_____ x 0.0031)
What are the two important variables in this question?
Oxygen content = ( Hb x 1.34 x SaO2) + ( PaO2 x 0.0031)
The two most important variables are Hb and SaO2
For each variable list one action you could take that would improve the O2 content and therefore improve O2 delivery
Increase flows, increase FiO2, increase Hb
Oxygen delivery = _______ x ________
Oxygen delivery= CaO2 x CO
What is the best indicator of oxygen delivery on VA ECMO
ECMO SvO2
What is the best indicator for oxygen delivery on VV ECMO
Patient SpO2, patient gasses
What influences oxygen delivery on VV ECMO
Patients lungs, recirculation, Hb, cardiac output, FiO2
What influences oxygen delivery on VA ECMO
Hb, CO, FiO2
What pressures are monitored in a neonatal pediatric circuit? What is the significance of each pressure
Venous pressure- monitors patients volume status
Pre-membrane - monitors the oxygenator for clots
Post-membrane - monitors afterload
What pressures are monitored in the cardiohelp circuit? What is the significance of each pressure?
Venous pressure- monitors patient volume status
Pre-membrane - monitors the oxygenator for clots
Post-membrane - monitors afterload
What pressures are monitored in the adult Rotaflow circuit? What is the significance of each pressure?
With Quadrox - no pressure monitoring
With Nautilus - pre-membrane & post-membrane
Pre-membrane - monitors the oxygenator for clots
Post-membrane - monitors afterload
What parameters are monitored by the venous probe on the cardiohelp?
Hb, HCT, Svo2, venous temp
What parameters are monitored by the Spectrum? Is this an on line or in line device?
Venous probe (SV02)
Arterial probe (Hb, Hct, SaO2)
Flow probe (blood flows, bubbles)
Describe zero flow mode on the cardiohelp circuit? When would this be used?
A mode that can be manually set to periodically allow for the pump RPMs to be on to adjust for just enough flow to prevent backflow but not have any forward flow. Used to assess a patient’s native CO during weaning without having to place clamps on the line
What is the most common complications in ECLS? Why?
Bleeding, anticoagulation
Lost 4 reasons you might emergantly remove a patient from ECMO
1) excessive bleeding
2) ICH
3) air embolism/clots
4) accidental decannulation
List 5 causes of circuit air entrapment
1) venous pigtail open on the negative pressure side
2) air from central lines (albumin on a pressure bag
3) high negative pressures causing cavitation
4) cracked hard plastics within the venous side of the circuit
5) From the oxygenator - blocked gas exhaust causes increased gas membrane pressures that can rupture the membrane and allow gas to bubble straight into the blood side
Define recirculation? List 4 factors that affect recirculation
When the blood from the return cannula is pulled directly into the pull cannula without being directed to the patient
1) cannula position and design
2) pump flow
3) cardiac output
4) intravascular volume
What is the major limiting factor for ECLS blood flow
Decreased Preload
If your PCO2 is high, what do you do to the sweep gas flow rate? At what increments is the sweep gas flow changed? How is the change assessed?
Increase it
Adults 0.5-1 L/min, neonates 0.1, peds 0.2-0.5
Redraw ABG
What is measured by the Hemochron signature elite?
Blood coagulation on fresh whole blood. ACT - activated clotting time
How is a parameter armed for the cardiohelp?
In the chain link page. You have to go into each parameter and arm/disarm manually
Can you describe the steps for getting the cardiohelp circuit ready to hand to the surgeon?
1) clamp the venous and Arterial lines near the oxygenator with tubing clamps
2) clamp all 4 big white Robertson clamps
3) break it apart using the quick disconnects and connect them forming a loop
4) open the circuit to be handed up to the surgeon sterile
5) instruct to clamp and cut the circuit. ( Clamp at the stickers indicated, cut between the clamps and quick connects.)
What is the difference between the cardiohelp and the Rotaflow pump head
Cardiohelp is built into the oxygenator, and it has 4 outflow channels to distribute flow more uniformly throughout the oxygenator
Rotaflow is a single outlet pump that uses a sapphire bearing
What are signs of cardiac tamponade on VA ECMO
Decreased flows, venous line chugging and more negative venous line pressure due to decreased venous return to the heart causing decreased Preload. Pulsatility would decrease or go away completely
What are signs of tension pneumothorax on VV ECMO
Decreased lung compliance, decreased SpO2, decreased flows due to decreased venous return to the heart causing a decreased Preload
What parameters do you inspect when doing your circuit checks? How often are they done? How often are they charted?
All of your parameters!! Pressures, flows, sweep, FiO2, temps, saturations, circuit is clear from clots/air, gas exhaust is free from obstruction
Every hour- charting (+ more often for significant events) & reperfusion cannula checks
Every 2 hours - sigh the membrane
Every 4 hours - flush pigtails (plus more often as clot formations form)
Which screen on the cardiohelp allows you to store your lab values
Press the little folder button with either the SvO2, Hct or Hb
What device is used for CRRT
NxStage
What line is clamped on Centrimag when changing pump to another external drive?
Both venous and Arterial lines closest to the patient
(Company will teach you to clamp only near the outflow of the pump)
What is the minimum RPMs to be sure of forward flow in Centrimag, cardiohelp and Rotaflow pumps? Why is this important?
1700 RPMs - backflow is bad
Where are primed ECMO circuits stored in this hospital
OR - outside of room 21
Neomart
ECMO room - PICU
CISCU - outside of room 134
List 4 blood products that your patient may receive. How is each product given for neonates? Does it make a difference if your patient is a neonate or an adult?
PRBCs - venous side, infusion port, with a syringe pump
FFP - venous side, infusion port, with a syringe pump
Platelets - Arterial side of the bridge, manually pushed 5cc every 5 mins, flush after giving the entire dose
Cryo- Arterial side of the bridge, manually pushed 5cc every 5 minutes, flush after giving the entire dose
All products are given peripherally for adults
For pediatrics, still give PRBCs and Albumin in the venous side. Prefer to give platelets peripherally but will give in the Arterial side of the bridge if access is limited.
Describe when crystalloid, Albumin (5% and 25%) and blood products are transfused
Hypovolemia causes a decreased Preload that causes decreased flow. Nothing placed on a pressure bag for ECMO patients in the CISCU
Crystalloid used when Hct is high and volume is needed
Albumin used to pull in any volume that is 3rd spacing in the extravascular space
Blood products are used to treat specifics
