ECMO (Extracorporeal Membrane Oxygenation ) PARAS KHANDHAR

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ECMO (Extracorporeal Membrane Oxygenation )

• Paras Khandhar
• Senior Talk

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When I think about Ecmo, I think
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ECMO in Adults? Isnt this a Peds thing?

• 1000 patients supported on ECMO at the University
  of Michigan were reviewed (retrospectively)
• VV-ECMO for respiratory failure provided survival
  to discharge
• 88 of 586 cases of respiratory failure in
  neonates
• 70 for 132 cases of respiratory failure in
  children
• 56 for 146 cases of respiratory failure in adults

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Introduction

• Mechanical circulatory support has evolved
  markedly over recent years.
• ECMO (extra corporeal membrane oxygenation) has
  become more reliable with improving equipment,
  and increased experience, which is reflected in
  improving results.

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Introduction

• ECMO is instituted for the management of life
  threatening pulmonary or cardiac failure (or
  both), when no other form of treatment has been
  or is likely to be successful.
• ECMO is essentially a modification of the
  cardiopulmonary bypass circuit which is used
  routinely in cardiac surgery.

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Introduction

• Instituted in an emergency or urgent situation
  after failure of other treatment modalities.
• It is used as temporary support, usually awaiting
  recovery of organs.

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Dynamics of ECMO

• Blood is removed from the venous system either
  peripherally via cannulation of a femoral vein or
  centrally via cannulation of the right atrium,
• Oxygenate
• Extract carbon dioxide
• Blood is then returned back to the body either
  peripherally via a femoral artery or centrally
  via the ascending aorta.

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Indications for ECMO

• Divided into two type
• Cardiac Failure
• Respiratory Failure

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Indications Cardiac Failure

• Post-cardiotomy
• when unable to get pt off cardiopulmonary bypass
  following cardiac surgery
• Post-heart transplant
• usually due to primary graft failure
• Severe cardiac failure due to almost any other
  cause
• Decompensated cardiomyopathy
• Myocarditis
• Acute coronary syndrome with cardiogenic shock
• Profound cardiac depression due to drug overdose
  or sepsis

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Indications Respiratory Failure

• Adult respiratory distress syndrome (ARDS)
• Pneumonia
• Trauma
• Primary graft failure following lung
  transplantation.
• ECMO is also used for neonatal and pediatric
  respiratory support
• This is where most of the research on ECMO has
  been done

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Decision to Institute ECMO

• Several considerations must be weighed
• Likelihood of organ recovery. only appropriate
  if disease process is reversible with therapy and
  rest on ECMO
• Cardiac recovery to either wait for further
  cardiac recovery to allow implant of device
  (LVAD) or to list for transplantation.
• Disseminated malignancy
• Advanced age
• Graft vs. host disease
• Known severe brain injury
• Unwitnessed cardiac arrest or cardiac arrest of
  prolonged duration.
• Technical contraindications to consider aortic
  dissection or aortic incompetence

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Configurations for ECMO

• ECMO can be inserted in 2 configurations
• Veno-venous
• Veno-arterial

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• Veno-arterial (VA) configuration
• Blood being drained from the venous system and
  returned to the arterial system.
• Provides both cardiac and respiratory support.
• Achieved by either peripheral or central
  cannulation

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Central ECMO Cannulation
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• Veno-Venous (VV) configuration
• Provides oxygenation
• Blood being drained from venous system and
  returned to venous system.
• Only provides respiratory support
• Achieved by peripheral cannulation, usually of
  both femoral veins.

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Peripheral ECMO Cannulation
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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.

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• Disadvantages
• Previously insertion of central ECMO required
  leaving chest open to allow the cannulae to exit.
• Increased the risk of bleeding and infection
• Newer cannulae are designed to be tunneled
  through the subcostal abdominal wall allowing the
  chest to be completely closed.
• Central cannula are costly (approximately 4 times
  as much as peripheral)

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Things to Think About

• Mechanical ventilation must be continued during
  ECMO support to try to maintain oxygen saturation
  of blood ejected from the left ventricle to at
  least above 90.
• ECMO flow can be very volume dependent
• ECMO flow will drop
• Hypovolemia
• Cannula malposition
• Pneumothorax
• Pericardial tamponade.

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Weaning of ECMO VV ECMO

• Actual ECMO flows do not need to be altered to
  assess native respiratory function
• Done by altering gas flow through the ECMO
  circuit
• Pt may be weanable
• Gas exchange is able to be maintained with a low
  FiO2 (lt30)
• Low fresh gas flow rates into the circuit (lt2
  L/min)
• Caveat RR and PEEP set on ventilator are not too
  high (e.g. lt25 breaths/min and lt15cmH2O,
  respectively).

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Weaning of ECMO VA ECMO

• Depends on cardiac recovery, Factors
• Increasing blood pressure
• Return or increasing pulsatility on the arterial
  pressure waveform
• Falling pO2 by a right radial arterial line
• indicating more blood is being pumped through the
  heart which may be less well oxygenated,
• Falling central venous and/or pulmonary
  pressures.
• It is important to note that cardiac outputs from
  pulmonary artery catheter are inaccurate on ECMO
• Most of the circulating blood volume is bypassing
  the pulmonary circulation

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Complications

• Falls into one of three major categories
• 1) Bleeding associated with heparinization
• 2) technical failure
• 3) neurologic sequelae

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Complications of ECMO

• Bleeding/Hemolysis
• Out of proportion to the degree of coagulopathy
  and patient platelet count
• Coagulopathy
• Continuous activation of contact and fibrinolytic
  systems by the circuit
• Consumption and dilution of factors within
  minutes of initiation of ECMO

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Complications of ECMO

• Thrombocytopenia
• Platelets adhere to surface fibrinogen and are
  activated
• Resultant platelet aggregation and clumping
  causes numbers to drop
• Non-pulsatile perfusion to end organs
• Kidneys
• Splanchnic circulation seems to be particularly
  susceptible
• GI bleeding, ulceration and perforation
• Liver impairment

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Complications of ECMO

• Mechanical Complications
• Tubing rupture
• Pump malfunction
• Cannula related problems
• Local complications Leg ischemia
• Particularly at peripheral insertion site of VA
• Air embolism/Thromboembolism
• Neurological Intracerebral bleeds
• Largely associated with sepsis
• Manifest as seizures or brain death

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Management of Complications

• Regular measurements of blood tests (Q6-Q8h)
• Coagulation Profile
• Platelet Count
• Hemoglobin
• Creatinine to evaluate for renal insufficiency
• Aggressive replacement of clotting factors,
  electrolytes, PRBC

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Outcomes of ECMO

• Good quality RCT of ECMO outcomes in adult
  population are lacking
• There are very promising studies in the Pediatric
  populations, however it is hard to know if this
  translates into the adult population.
• Completed yet unpublished CESAR Trial shows some
  potential impact in ECMO research

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CESAR

• Conventional Ventilation or ECMO for Severe Adult
  Respiratory Failure
• Preliminary results released at 37th Society of
  Critical Care Medicine Congress in Honolulu
  February 2008

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CESAR

• Randomized controlled trial to assess the impact
  of ECMO on survival without severe disability by
  6 months in patients with potentially reversible
  respiratory failure
• Severe disability was defined as confined to bed
  and unable to dress or wash oneself

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CESAR

• Conducted from 2001-2006
• Adults were randomized either to VV ECMO at
  Glenfield Hospital, Leicester, England (90
  patients) or continuing conventional care at
  referral hospitals (90 patients).
• The conventional group underwent standard
  clinical practice in the UK
• Conventional Ventilator

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CESAR

• ECMO
• 57 of 90 met primary endpoint
• Conventional ventilation group
• 41 of 87 met primary endpoint

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CESAR

• RRR 0.69 (95 CI, 0.050.97 P 0.03)
• Benefit of ECMO seen regardless of age, duration
  of high-pressure ventilation, primary diagnosis
  at trial entry, and number of organs failing.

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Further Studies

• CESAR study shows potential impact for VV ECMO,
  however studies to evaluate impact for VA ECMO
  are lacking
• This is where potential studies can be done

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Summary

• ECMO is instituted for the management of life
  threatening pulmonary or cardiac failure (or
  both), when no other form of treatment has been
  or is likely to be successful.
• ECMO is essentially a modification of the
  cardiopulmonary bypass circuit which is used
  routinely in cardiac surgery.
• ECMO can be inserted in 2 configurations
  Veno-venous Veno-arterial
• Completed yet unpublished CESAR Trial shows some
  potential impact in ECMO research

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Questions??
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Bibliography

• Bartlett RH. Extracorporeal life support registry
  report 1995. ASAIO J 1997431047.
• Conrad SA, Rycus PT, Dalton H. Extracorporeal
  life support registry report 2004. ASAIO J
  200551410.
• Fiser S, Tribble CG, Kaza AK, Long SM, Zacour RK,
  Kern JA, Kron IL. When to discontinue ECMO for
  postcardiotomy support. Ann Thorac Surg
  2001712104.
• Glauber M, Szefner J, Senni M, Gamba A, Mamprin
  F, Fiocchi R, Somaschini M, Ferrazzi P. Reduction
  of haemorrhagic complications during mechanically
  assisted circulation with the use of a
  multi-system anticoagulation protocol. Int J
  Artif Organs 19951864955.
• Hitt E. CESAR trial extracorporeal membrane
  oxygenation improves survival in patients with
  severe respiratory failure. Medscape Medical News
  www.medscape.com 2008
• Marasco SF, Esmore DS, Negri J, Rowland M,
  Newcomb, A, Rosenfeldt F, Bailey M, Richardson M.
  Early institution of mechanical support improves
  outcomes in primary cardiac allograft failure. J
  Heart Lung Transplant 200524(12) 203742.
• Peek GJ, Clemens F, Elbourne D, Firmin R, Hardy
  P, Hibbert C, Killer H, Mugford M, Thalanany M,
  Tiruvoipati R, Truesdale A,Wilson A. CESAR
  conventional ventilatory support vs.
  extracorporeal membrane oxygenation for severe
  adult respiratory failure. BMC Health Serv Res
  200623(6)163.
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