Ecmo va

VENOARTERIAL
ECMO FOR
ADULTS
D R M AYA N K G U P TA

INTRODUCTION
• ECMO is a portable modification of cardiopulmonary bypass capable of
supporting critically ill patients with refractory cardiopulmonary failure
for days to weeks.
• After the landmark CESAR (conventional ventilatory support versus
extracorporeal membrane oxygenation for severe adult respiratory
failure) trial, in which ECMO appeared to be superior to the ventilator in
the adult population since then this modality has been increasingly
popular.
• According to the Extracorporeal Life Support Organization (ELSO), an
international voluntary registry, the number of adult cardiac ECMO runs
increased 1,180% in the last decade, from <200 between 1997 and 2007
to over 2,000 to date

OVERVIEW
• ECMO was initially used primarily in neonatology. ECMO, predominantly
veno-venous (VV), was first used in adults with severe but potentially
reversible lung disease, such as influenza pneumonia and adult
respiratory distress syndrome.
• Evidence favoring adult VA-ECMO came from prospective observational
propensity-matched studies of extracorporeal cardiopulmonary
resuscitation (ECPR), both demonstrating a neurologically intact survival
benefit over conventional cardiopulmonary resuscitation (CPR).

HEMODYNAMICS WITH
CARDIOGENIC SHOCK AND VA-ECMO
• The hemodynamic condition of the LV in all types of cardiogenic shock
is best illustrated by the pressure volume (PV) loop.
• Typically, in cardiogenic shock, independent of underlying etiology, LV
contractility, reflected by Emax, defined as the maximum slope at the
end-systolic PV point, is reduced and LV end-diastolic pressure (LVEDP)
is increased

• Point 1 notes the end of isovolumic
relaxation. Phase 1 to 2 defines diastole.
• Point 2 (end-diastole) represents maximum
left ventricular (LV) volume and the onset of
isovolumic relaxation.
• Point 3 defines peak isovolumic contraction,
where LV pressure exceeds aortic pressure
and marks theonset of blood ejection into the
aorta. Phase 3 to 4 defines the systolic
ejection phase, and illustrates the decrease in
LV volume.
• Point 4 defines the end-systolic PV point
where aortic pressure exceeds LV pressure
and marks aortic valve closure. The width of
the PV loop represents stroke volume (SV),
defined as the difference between end-
diastolic and end-systolic volumes
• Emax represents load-independent LV
contractility defined as the maximum slope of
the end-systolic PV point under various
loading conditions.
• Effective arterial elastance (Ea) is a
component of LV afterload, and is defined as
the ratio of end-systolic pressure and SV

• PV loop in acute myocardial infarction
(blue loop). LV contractility (Emax2),
• LV systolic pressure (LVSP), SV, and
stroke work are mildly reduced.
• LV end-diastolic pressure (LVEDP) is
increased.

• PV loop in acute on chronic heart
failure cardiogenic shock (dark gray
loop).
• LV contractility (Emax2) is severely
reduced, LVEDP and LV end-diastolic
volume are significantly increased
and SV is significantly reduced.

• The negative impact of venoarterial
extracorporeal membrane oxygenation
(ECMO) on PV loop curves with a flow
dependent increase in LVEDP (asterisks) and
associated increase in effective Ea.
• An associated flow-dependent decrease in LV
SV is depicted in the PV loops and is
represented by the width of the PV loop as the
volume difference between end-systolic and
end-diastolic volumes. Burkhoff et al.
• In patients with significantly reduced ejection
fractions at baseline, VA-ECMO may cause an
increase in wall stress and oxygen demand,
which impedes myocardial recovery and may
precipitate progressive pulmonary edema and
acute lung injury and worsen outcomes
• THE ECMO LUNG

• Multiple strategies to reduce pulmonary congestion during VA-ECMO
support are-
Increase in forward flow by introducing inotropes or devices such as
Impella or intra-aortic balloon pump (IABP)
Decrease in LV afterload by placement of an IABP.
Mechanical decompression of the LV by shunting the blood to the right
side via atrial septostomy or removal of LV volume via placement of
Impella, transseptal cannulation of the LV or left atrium (LA), or direct
surgical LV apical drainage
Removal of fluid from intravascular space using diuretic agents,
ultrafiltration, or hemodialysis.
Reduction in ECMO speed and consequently ECMO flow (which may not
be well tolerated).

• Two studies demonstrated smaller LV dimensions and lower pulmonary
artery pressures with VA-ECMO plus active IABP support
• In a retrospective cohort study of 1,650 adult patients with cardiogenic
shock from the nationwide Japanese national inpatient database, 28-day
and in-hospital mortality were significantly lower with VA-ECMO plus
IABP (48.4% vs. 58.2%; p ¼ 0.001) than with VA-ECMO alone (55.9% vs.
64.5%; p ¼ 0.004)
• However, an observational meta-analysis of 16 studies showed a lack of
survival benefit of VA-ECMO with concomitant IABP
• ECMO provides continuous blood flow. Any pulsatility, if present, is
created by the residual function of the LV.
• In severe cases of cardiogenic shock or in the presence of cardiac
tamponade, Korotkoff sounds may be absent and only mean blood
pressure can be measured, necessitating use of an arterial line

CONTRAINDICATIONS
• Absolute
Severe irreversible noncardiac organ failure limiting survival (e.g., severe
anoxic brain injury or metastatic cancer)
Irreversible cardiac failure if transplantation or longterm VAD are not
considered
Aortic dissection
• Relative
Severe coagulopathy or contraindication to anticoagulation, including
advanced liver disease
Limited vascular access (severe peripheral arterial disease, extreme obesity,
amputated limbs, among others)

PREDICTORS OF MORTALITY
 Age & female sex,
 longer support time
 decreased cardiac function at
baseline
• high lactate concentration,
• peripheral vascular disease
• chronic obstructive lung
disease
• renal dysfunction
• Stroke
• infection,
• hypoglycemia
• alkalosis
• device insertion during CPR,
• decreased urine output

CARDIAC ARREST
• ECPR, the acronym , is defined as the application of rapid-deployment
ECMO to provide circulatory support in patients who fail to achieve a
sustained return of spontaneous circulation (ROSC) (defined as 20
consecutive minutes without a need for chest compressions by
conventional CPR).
• A recent prospective cohort study of in- and out-of-hospital ECPR in
selected patients boasted 54% survival to discharge with full
neurological function (Chen YS, Lin JW, Yu HY, et al lancet 2008)
• A recent meta-analysis of ECPR studies showed that ECPR was
associated with an absolute increase in 30-day survival of 13% and a
higher rate of favorable neurological outcome at 30 days compared with
conventional CPR
(Ouweneel DM, Schotborgh JV, Limpens J, et al. Intensive Care Med 2016)

• Inclusion criteria
Age <70 years
 Initial rhythm of ventricular fibrillation or ventricular tachycardia
 Witnessed arrest
 Bystander CPR within 5 min
 Failure to achieve ROSC within 15 min of beginning CPR

• Exclusion criteria
Asystole as an initial rhythm
 Unwitnessed arrest
 Total cardiac arrest time >60 min
 Pre-existing severe neurological or systemic disease (including stroke,
severe dementia, advanced malignancy, chronic neuromuscular
dystrophy, psychiatric conditions, anoxic brain injury)
 Contraindications to anticoagulation
 Acute aortic dissection
 Suspicion of shock due to hemorrhage or other noncardiovascular
cause
 Known “do not resuscitate” (DNR) status

CARDIOGENIC SHOCK
• Cardiogenic shock is a critical condition of hemodynamic instability with
compromise of end-organ and tissue perfusion.
• Commonly accepted hemodynamic parameters defining cardiogenic
shock include cardiac index <2.0 l/min/m2 with systolic blood pressure
<90 mm Hg and pulmonary capillary wedge pressure >/=24 mm Hg,
and dependency on at least 2 inotropes or vasopressors, with or without
IABP. (Pagani FD, Lynch W, Swaniker F, et al)

Survival Benifit-
• Cardiogenic shock due to acute myocardial infarction ranges
from 19.2% (Aiba T, Nonogi H, Itoh T, et al. ) to 87.5%.
FA, Domanski MJ, Hernandez TJ, Punja S. et al.)
• Survival outcomes range from 47% to 83.3% (39,40) for
myocarditis.
• Survival outcomes range from 57% to 100% for pulmonary
embolism.

REFRACTORY VENTRICULAR
TACHYCARDIA
• VA-ECMO is successfully used to hemodynamically stabilize patients in
refractory ventricular tachycardia or fibrillation, regardless of etiology.
• Creating a continuous blood flow, ECMO maintains adequate
hemodynamics in the setting of ventricular tachycardia, ventricular
fibrillation, or electrical storm while antiarrhythmic therapies are
administrated or radiofrequency ablation is performed.

The logistics of placing a patient on ECMO can be divided into
several steps, each requiring a specific skill set –
• ACTIVATION-
Activation of the ECMO team requires (except in emergency
circumstances) a prior interactive discussion between team
members to make an initial assessment regarding the probability
success based upon the clinical scenario, institutional capabilities
and survival estimates.

• CANNULATION-
• Cannulation is critically important.
• Access is usually achieved percutaneously in the
catheterization laboratory or at the bedside, as may be
needed during ECPR.
• The size of the cannulas required for arterial and venous
cannulation for VA-ECMO support is not clearly defined by
current published data.
• It is usual practice to select cannulas that will yield full
for a given patient, that is, to achieve an index of 2.2
• The flow required for full support in an adult is about 60
cm3/kg/min.

MANAGEMENT ECMO flow
• Usually, an ECMO flow of 50 to 70 ml/kg/min (w4 to 6 l/min) is
for full the aorta to be filled by retrograde flow from the arterial
cannula.
• This may result in an elevated LVEDP, elevated pulmonary capillary
wedge pressure, and ultimately pulmonary congestion.
• An IABP or interatrial balloon septostomy can be performed to shunt
blood from the LA to the right atrium and reduce the elevated left-
pressures
• Another disadvantage to VA bypass is that any particles, bubbles, or
emboli that may be infused into the arterial or venous circuit can result
in an adverse cerebral event
• Finally, the decreased flow through the lungs may permit the
development of microvascular intrapulmonary thromboses

• Monitoring-
• An ECMO patient should invariably have an arterial line and
may have a pulmonary artery catheter.
• A Swan-Ganz catheter should be placed and used as a tool to
monitor pulmonary arterial pressure as a surrogate of LV
distention.
• Intermittent measurement of lactate might be helpful

• Anticoagulation-
• Systemic anticoagulation therapy minimizes interaction of blood
products with the surface of the ECMO circuit.
• Heparin is the most common anticoagulant, used according to a
standard weight based protocol and monitored either by
thromboplastin time, goal 50 to 75 s (1.5 to 2.5 baseline) or anti-
factor Xa, goal 0.3 to 0.7 IU/m.
• Some centers prefer to follow the activated clotting time, due to
bedside availability and rapid turnaround time, goal 180 to 220 s.
• Direct thrombin inhibitors, such as parenteral bivalirudin and
argatroban, represent alternatives to heparin in individuals with
heparin-induced thrombocytopenia activated partial
thromboplastin times between 50 and 60 s

• VENTILATOR MANAGEMENT
• Patients on ECMO may or may not require ventilator support.
• Because ECMO provides up to full gas exchange, the conscious patient
in cardiogenic shock can breathe spontaneously while on ECMO,
regardless of respiratory function.
• Ventilator support may be necessary for airway protection in patients
requiring sedation, such as cardiac arrest patients.
• Most centers use low tidal volume ventilation (3 to 5 ml/kg) to reduce
the risk of lung injury.
• Protective mechanical ventilation settings include a rate of <8/min,
positive endexpiratory pressure of 10 to 15 Torr, fraction of inspired
oxygen <0.40, and low tidal volume

• Hemodialysis on ECMO.
• Continuous VV hemodialysis can be done via ECMO circuit or via
separate vascular access
• Temperature
• Should ECMO be used for a patient after an anoxic insult,
maintaining a temperature no higher than 36F for up to 24 h
might be of value

• WEANING
• ECMO flow is decreased by approximately 1 l/h over a period of 3 to 4
h, although slower rates of weaning at 0.5 l every 6 to 24 h have been
reported as well (Stub D, Bernard S, Pellegrino V, et al CHEER TRIAL
2015)
• The patient should be able to maintain a mixed venous saturation
>65%, and an arterial saturation of >90% with an ECMO flow <1.5

COMPLICATIONS
• LIMB ISCHEMIA
• limb ischemia occurred in 16.9% of patients supported by peripheral
VAECMO
• Fasciotomy, due to compartment syndrome, was needed in 10.3% of
patients, with 4.7% requiring amputation (Cheng et al)
• The use of prophylactic antegrade perfusion catheters has probably
reduced the incidence of this complication.
• Per Lamb et al. (64), none of 55 patients with a distal perfusion
placed prophylactically developed limb ischemia, as opposed to 12 of
patients without such a catheter.

• Typical symptoms of limb ischemia include pallor, loss of pulses, and
gangrene.
• Compartment syndrome is rarely seen in profoundly ischemic limbs
before reperfusion, with a distal perfusion catheter.
• If measurement of the compartment pressures reveals a value above
20mm/Hg , fasciotomy is usually required.
• A high index of suspicion is necessary as are frequent Doppler checks
and hourly monitoring.

• STROKE
• Ischemic and hemorrhagic stroke occur in approximately 4% of VA
ECMO patients (Mégarbane B, Deye N, Aout M, et al)
• Ischemic stroke is most common in ECPR patients, diagnosed in 7% of
successful resuscitations.
• Cannulation via the carotid artery triples the risk of ischemic stroke
compared with femoral artery cannulation.
• One in 4 cerebral ischemia patients on VA-ECMO survive, whereas
1 in 10 cerebral hemorrhage patients survives , usually with
deficit.
• The cause of stroke is multifactorial, with thromboembolic events,
systemic anticoagulation, and hemodynamic instability thought to
contribute.

• BLEEDING
• Patients on VA-ECMO are typically anticoagulated and prone to
bleeding
• For optimal blood oxygen saturation, hemoglobin should be
between 8 and 10 mg/dl
• Bleeding is treated by reducing the dosage of heparin or stopping
anticoagulation
• A number of reports suggest that it is safe to withdraw anticoagulation
for up to 3 days in circumstances of anticoagulation intolerance
YS, Cho DY, Sohn DS, et al)

• INFECTION
• The most likely infectious complications of VA-ECMO are bacteremia
and sepsis, with longer ECMO runs associated with higher infection
rates.
• More than 53% of adults acquire an infection within 14 days of ECMO
initiation.
• Mortality in patients with complications reaches 60%..

• HARLEQUIN SYNDROME-
• As the LV recovers, it ejecting blood it receives from the pulmonary
circulation.
• Forward flow of deoxygenated blood from failing native lungs mixes
unpredictably with retrograde flow from the oxygenator, which can
result in inadequate delivery of oxygenated blood into the aortic arch,
resulting in upper body and brain hypoxia.
• This phenomenon, known as Harlequin syndrome
• This phenomenon, known as Harlequin syndrome, may result in
of the upper extremities while the lower extremities appear pink.
• Saturation monitoring for Harlequin syndrome is performed at the
hand, forehead, nose, or right ear, and arterial blood gas should be
obtained from a right arm arterial line.

CONCLUSIONS
• VA ECMO is a powerful tool that needs to be used judiciously
• Appropriate infrastructure, appropriate skill set of team members, and
thorough assessment of each ECMO candidate, with an evaluation of
indications and contraindication to ECMO support, are key steps to
ensure optimal outcomes

Ecmo va

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