Types of ECMO Support Flashcards
Who can benefit from ECMO?
Patients who have reversible lung and/or heart condition that has responded maximal medical therapy
What is ECMO utilized for?
Cardiac Failure
Respiratory failure
Cardiac Failure
the inability of the heart to supply sufficient blood flow meet the needs of the body
Respiratory Failure
inadequate gas exchange by the respiratory system, resulting in arterial O2 and/or CO2 levels failing to be maintained in normal ranges
Who’s Waiting for the “ECMO Train”?
Primary respiratory failure (neonatal)
Primary cardiac failure (all)
Primary respiratory failure (adults)
Primary respiratory failure (peds)
What causes Primary Respiratory Failure (Neonatal)
Meconium Aspiration
Sepsis
CDH (Congenital diaphragmatic hernia)
Persistent Pulmonary Hypertension (PPHN)
Increased PAP will lead to what?
Intrapulmonary shunting hypoxia and acidosis development
ELSO Neonatal ECMO Criteria: Indications
Oxygenation Index 20- consider ECLS
Oxygenation Index 40- ECLS indicated
Oxygenation Index Equation
(Mean Airway P x FiO2 x 100)/ Post ductal PaO2
What causes primary cardiac failure (Neonatal and Adult)
Post-cardiotomy failure - unable to wean from CPB Myocarditis Cardiomyopathy Cardiogenic shock Sepsis
ELSO Cardiac Criteria
Cardiac Index -5 x 3 hours (but less than 12 hrs)
Mean BP w/ oliguria: NB
Primary Respiratory Failure (Adults and Peds)
ARDS Pneumonia Viral Trauma Primary graft failure following lung transplanation
ELSO Pediatric Criteria (Indications)
While no absolute indicators are known, consideration for ECMO is best within the first 7 days of mechanical ventilation at high levels of support
ELSO Adult Respiratory Criteria
Hypoxic respiratory failure due to any cause (primary or secondary) ECLS should be considered when the risk of mortality is 50% or greater, and is indicated when the risk of 80% of greater
50% mortality risk can be identified by….
PaO2/FiO2 90% and/or Murray score 2-3
80% mortality risk can be identified by…
PaO2/FiO2 90% and Murray score 3-4
Adult Respiratory Criteria
CO2 retention due to asthma or permissive hypercapnia with a PaCO2 > 80
Inability to achieve safe inflation pressures (Pplat = 30 cm HO) is an indication for ECLS
Severe air leak syndromes
Who else gets on ECMO?
Patients that don’t always fit the criteria
last resort maneuver
Poor patient selection =
poor outcomes
Normal Techniques for ECMO Support
V-A
V-V
VV Dual Lumen (VVDL)
Modified Conversion Tehcniques
VA-V (VA gets additional venous return)
VV-A (VV becomes VVA)
VVDL-A (VVDL becomes VVDL-A)
What is the first big question in ECMO?
what type of ecmo do i need?
Types of ECMO
Cardiac support
Respiratory support
Cardiac and respiratory support
What is the second big question in ECMO?
Peripheral
central
Central vs Peripheral Cannulation: Advantages
Flow from Central ECMO is directly from the outflow cannula into the aorta provides antegrade flow to the arch vessels, coronaries and the rest of the body.
In contrast, the retrograde aortic flow provided by peripheral leads to mixing in the arch
Central vs Peripheral Cannulation: Disadvantages
Previously insertion of central ECMO required leaving chest open to allow the cannula to exit.
Central cannula are costly (approx 4x times as much as peripheral)
What is the risk of leaving the chest open?
Increased risk of bleeding and infection
How are the newer cannulas designed?
Newer cannula are designed to be tunneled through the subcostal abdominal wall allowing the chest to be completely closed
Venoarterial (V-A) ECMO
venous blood is drained through a single lumen venous cannula, oxygenated, heated and return to patient via a single lumen arterial cannula
What is the standard ECMO procedure used in most neonatal ICUs?
Veno-arterial bypass
Why choose V-A ECMO?
Almost complete cardiopulmonary support
Allows significant cardiac and pulmonary rest
Why NOT choose VA ECMO?
Increases LV afterload Lowers pulse pressure Coronary oxygenation by LV blood "Cardiac Stun" Decreased cerebral autoregulation neonatal carotid loss
Pathological Processes Suitable for V-A ECMO (Common)
Cardiogenic shock
Post cardiac surgery
Drug overdose with profound cardiac depression
Myocarditis
Early graft failure: heart-lung transplant
Pathological Processes Suitable for V-A ECMO (Other)
pulmonary embolism cardiac or major vessel trauma pulmonary hemorrhage pulmonary trauma actue anaphylaxis sepsis bridge to transplant
Venovenous ECMO
Venous blood is drained through a double lumen cannula, oxygenated, heated and returned to patient via holes in the distal ends of the cannula
How are the cannulas placed in V-V EcMO?
In VV ECMO, a double-lumen cannula is placed through the right jugular vein into the right atrium
How is blood circulating in V-V ECMO?
Desaturated blood is drawn from the RA, through the outer fenestrated venous catheter wall, and oxygenated blood is returned through the inner lumen of the catheter and is angled to direct blood across the TV
How do you avoid mixing?
Cannula position
V-V ECMO Diagnosis (Common)
Severe pneumonia
ARDS
ACute lung (graft) failure following transplant
pulmonary contusion
V-V ECMO Diagnosis (Other)
Smoke inhalation
Status asthmaticus
Airway obstruction
Aspiration syndromes
Common Cannulation Sites: VA
Right internal jugular vein (or femoral vein)
Right common carotid (axillary or aorta)
Common Cannulation Sites: VV
Internal jugular vein alone; jugular-femoral, femoro-femoral or sapheno-saphenous veins or right atrium
Usual Arterial PaO2 in VA vs VV
VA: 60-150 torr
VV: 45-80 torr
Indicators of oxygen sufficiency: VA
Mixed venous saturation of PaO2
Calculated oxygen consumption
Indicators of oxygen sufficiency: VV
combination of SaO2 or PaO2, cerebral venous saturation, and premembrane saturation trend
Cardiac Effects: VA
Decreased preload; increased afterload
CVP varies, pulse pressure low, Coronary oxygenation provided by left ventricular blood. “Cardiac stun” syndrome
Cardiac Stun Syndrome
Narrow pulse pressure and equal pt/circuit ABGs
Cardiac Effects: VV
Negligible effects
CVP, pulse pressure unaffected. May improve coronary oxygenation. May reduce RV afterload
Oxygen delivery capacity: VA
High
oxygen delivery capacitiy: VV
Moderate. Improves with a cephalad drain
Circulatory Support: VA
Partial to complete
Circulatory Support: VV
No direct support, but increased oxygen delivery to coronary and pulmonary circulation can improve cardiac output
Benefits of VA ECMO
Cardiac and respiratory support
Benefits of VV ECMO
preserves physiologic pulsatility decrease for ischemic lung injury thromboembolic enter pulmonary circulation avoids ligation of carotid artery may decrease risk of neurologic injury
How does VV decrease risk of neurologic injury?
Blood entering cerebral arterial tree is less highly oxygenated and under less pressure
Disadvantages of VA ECMO
ligation of carotid artery
lack of normal pulsatility
Disadvantages of VV ECMO
decline in renal function during first 48 hours
Requirement of two site cannulation for larger patients
no direct circulatory support
Recirculation
The shunting of arterial blood back into the venous lumen, common occurs during V-V ECMO and renders the monitoring of the venous line oxygen saturation no longer reflective of patient mixed venous oxygen saturation SvO2
How do you know if theres more recirculation?
Higher SVO2
Recirculation Fraction Calculation
R = [SO2 (preox) - SVO2 (pt)] / [SO2 (postox) - SvO2 (pt)]
R= recirculation factor %
SvO2 is the PATIENT not the venous line
VA ECMO Flows
Neonate: 100-150 cc/kg/min
Pediatric: 75-100 cc/kg/min
Adult: 50-75 cc/kg/min
VV ECMO Flows
Neonate: 100-120 cc/kg/min
Pediatric: 90-100 cc/kg/min
Adult: 75-90 cc/kg/min
VV Conversion to VVA
Addition of an arterial cannula when you’re already on VV
Requires: “Y” venous lines of both arms of the dual lumen cannula or both venous lines to the single venous line to the pump
Cannulate artery and put the ECMO outflow line to it
in need of arterial support after VV cannulated: have ot come off bypass
VA Conversion to VAV
In need of more venous return after V-A cannulated
start with V-A ECMO
need to add another venous to increased drainage
VV conversion to VAV
addition of a venous cannula when youre already on VA
Requires: “Y”
Cannulated artery and put hte ECMO added to venous line and 2 venous cannulas not flow to the pump
