ECMO에대한이해와환자관리

2013. 4. 26

강영애, CNS

흉부외과 중환자실

서울아산병원

Clinical decision making (1)♣ 47y/M CABG 시행후 ICU care

CVP

PAP

ECMO insertion

Clinical decision making (2)

Volume replacement

Inotropics maximal infusion

BP drop

Increased CVP

Tissue malperfusion sign

Sustained

low cardiac output state

ECMO indication

◈ Cardiogenic shock

- Inadequate tissue perfusion manifested as

hypotension, low cardiac output despite optimal

vascular volume

- AMI, myocarditis, decompensated heart failure,

recurrent life threatening arrhythmia

- Bridge to transplant /implantable circulatory

support

◈ Respiratory failure

Concepts

• ECMO : ExtraCorporeal Membrane Oxygenator

• ECLS : ExtraCorporeal Life Support

• ECLS is the use of mechanical devices to

temporarily support heart or lung function

(partially or totally) during cardiopulmonary failure,

leading to organ recovery or replacement

Basic principle of ECMO

Blood is drained from the right atrium

Blood is oxygenated

Excess CO2 is removed

Oxygenated blood is returned to the aorta

- (or for VV ECMO into the right atrium)

ECMO blood mixes with blood ejected

from left ventricle

Advantage of ECMO

Provide of cardiac and pulmonary support

Simple & rapid peripheral insertion of cannulas

Performed during cardiopulmonary resuscitation

-> time to recovery

Less costly than other forms of mechanical

circulatory support

CAPIOX EBS (Terumo)

QUADROX PLS (MAQUET)

BIO pump (Medtronic)

Configuration

Membrane

oxygenator

Blood

pump Drainage cannula

: inlet cannula

Return cannula

: outlet cannula

Control

console

Centrifugal pump

• Stir your coffee!

• Fluid is forced to the

outside of the path of

rotation (toward pump

outlet)

• Create a low pressure

zone in the center (at

the pump inlet)

• Controlled by RPM

Control console

Operator interface

Set pump RPM

Display flow

measurement

Incorporate pressure

monitoring, alarm

Improved centrifugal pump

• 1st and 2nd generation centrifugal pump

: high friction & heat generation

-> greater hemolysis

• Newest generation centrifugal pump

: jewel bearing, magnetic levitation,

improved flow dynamics, mechanic efficiency

-> very low friction & hemolysis,

negligible heat generation

Principle in practice

• Set RPM -> Pump flow is constant

• But pump flow is dependent on preload and sensitive to afterload

• Reduced preload = reduced pump flow

Hypovolemia, venous cannula occlusion

• Increased afterload = reduced pump flow

Circuit obstruction, small arterial cannula,

blood viscosity

Oxygenator

Hollow fiber diffusion

membrane

Gas diffusion through

membrane

Eliminate plasma leakage,

prevent formation of

microbubble

-> increased valid time

Gas blender

CO2 제거 FiO2 조절 Membrane

oxygenator연결

ECMO types

A. Veno-venous type

- for respiratory support,

- no hemodynamic

support

B. Veno-arterial type

- for cardiac support,

- appropriate for

respiratory support

A. B

Vascular access in VA type ECMO

• Non-postcardiotomy

- Percutaneous femoral artery & vein (rapid access),

- Percutaneous jugular vein

(advance to Rt. atrium if possible),

- Common carotid artery via surgical exploration

• Postcardiotomy

- Intrathoracic cannula

Vascular access

Optimal cannula position

Hemodynamic parameter

• Bypass flow : 4 L/min

• Cardiac index : at least 2.4 L/min/m2

• Setting : Pump RPM, FiO2 & gas flow control

• Check the volume status

( Volume fluctuation )

• Check oxygenator function

( Oxygenator ABGA )

Ventilator management

• Ventilator manage at low setting to allow lung rest

• Minimize atelectasis, maximize oxygenation

• Low rate with long inspiratory time,

low plateau inspiratory pressure (<25mmHg),

low FiO2 (<30%),

PEEP at any level (high PEEP level inhibit

venous return)

• Blood gas management : ECMO >> ventilation

Anticoagulation

• Heparin ivs (50-100u/kg) at the time of cannulation,

continuous infusion 10-15u/kg/hr

• Nafamostat mesilate (Futhan)

• Check ACT hourly until titration

ACT - whole blood clots in response to fibrin activating

agent

1.5 times normal ACT -> 150-180sec

ECMO weaning time (ECMO flow 1.5-2L/min)

-> 200-250sec

Two circulation syndrome (VA type)

• ECMO blood mixes with blood

ejected from Lt. ventricle

• Coronary & proximal arch

perfusion by unoxygenated blood

• Different PaO2 between upper

and lower extremities

• Management

- Minimize pulmonary circulation

: maximum drainage

- ABGA monitoring via Rt. arm

- Negative fluid balance

LA decompression

• Returning blood flow to Lt.

atrium

-> Interfere heart decompression

-> Lung congestion

-> Heart recovery delay

LA vent insertion

Management of distal vessels

• If the access is via the femoral artery, distal arterial flow

to leg is inadequate

• Separate perfusion line placed in the superficial femoral

artery (distal perfusion line)

Renal, fluid balance

• Normal body wt. no fluid overload

• MAP up to 70mmHg, CVP 5-10mmHg

• Acceptable urine output : 1-2ml/kg/hr

• Consider pulsatile perfusion

• Hemofiltration through EBS circuit

• Fluid management for ARF

: early CRRT

• Daily body weight check

: negative I/O balance

Infection & nutrition

• Prevention : if possible percutaneous ECMO

• Surveillance culture : blood, urine, sputum

• Disruption of normal infection barrier

- Prophylactic antibiotics, no standard policy

• Nutritional support

- Parenteral nutrition

- TPN << enteral feeding

- NG tube feeding within 48hr

Bleeding

• d/t systemic anticoagulation, thrombocytopenia,

thrombocytopathy

• Cannulation site, operation site, catheter passage,

mucous membrane, GI bleeding, brain parenchyma

• Optimal anticoagulation state

: optimal ACT,

platelet transfusion : > 80,000

hematocrit : 35~40%

• During cannulation & management for first 12-24hr

• To prevent air embolism by spontaneous breathing ,

to minimize metabolic rate, to avoid movement,

for patient comfort

• Depending on patient’s level anxiety & discomfort

• Sedation should be minimal, but be sure the risk of

decannulation

Sedation

Others

• Hourly neurologic exam

• Positioning & skin care

- Depending on primary condition,

Possible to extubate for cardiac support

• Check peripheral circulation, compartment syn.

• Temperature care

- Close to 37℃ or mild hypothermia(32-34℃) during first

24-72hr in condition which lead to hypoxic brain damage

• Check chest X-ray, echocardiography for cardiac support

◈ Trial off during VA type ECMO

• With evidence of improved hemodynamic parameter,

contraction on echocardiography

• Adjust the dose of inotropes, vasopressors & ventilator

setting

• Clamp off extracorporeal circuit (or bridge) and follow

perfusion and gas exchange

• Anticoagulation is continued during trial off

ECMO trial off

Decannulation

• After heparin stop for 30-60min

• Percutaneous access can be removed directly and

bleeding controlled by topical compression

• When removing venous cannula in spotaneous

breathing state, air can enter venous blood

-> valsalva maneuver on ventilator

or short-term pharmacological paralysis