Extra corporeal membrane oxygenation

7/29/2019 Extra corporeal membrane oxygenation

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Management of Infants

requiring ECMO

Sixto F. Guiang, III

Dept. of PediatricsUniversity of Minnesota


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Extracorporeal membrane

oxygenation- ECMO Mode of cardiopulmonary support

Pulmonary failure

Cardiovascular insufficiency

Adapted from cardiopulmonary bypass done

in OR

Infants, children, and adults


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Neonatal ECMO = 73 % of all ECMO

VV ECMO = 20% of all Neonatal Pulmonary


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Recent ECMO Pediatrics 2000;106:1334-1338

Fewer patients

Longer ECMO runs

Longer time prior to ECMO

Higher mortality


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Extracorporeal Life Support

Organization: ELSO Develop guidelines for use

Quality assurance

Education Text

Regulatory issues

Database

Clinical needs Research needs

www.elso.med.umich.edu/
http://localhost/var/www/apps/conversion/tmp/scratch_8//ecmo%20nutrition%20talk/exrtraslides.ppthttp://localhost/var/www/apps/conversion/tmp/scratch_8//ecmo%20nutrition%20talk/exrtraslides.ppt


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Inclusion ECMO Criteria Gestational age of at least 34 weeks

Weight >1.7-2.0 kg


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Inclusion / Exclusion

Guidelines age of at least 34 weeks

Weight >1.5-2.0 kg

Potentially reversible process Absence of uncorrectable cardiac defect

Absence of major intracranial hemorrhage

Absence of uncorrectable coagulopathy

Absence of lethal anomaly

Absence of prolonged mechanical ventilationwith high ventilatory settings


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Reversible Lung Disease No prospectively defined criteria have been

developed

Pre-ECMO gas exchange is not predictive ofbaseline lung capability

ECMO utilized in Lung hypoplasia

Congenital diaphragmatic hernia

Renal anomalies

Hydrops fetalis


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Oxygenation Failure Alveolar - arterial oxygen tension gradient

[760 - 47)-paCO2] - paO2

605 - 620 torr for greater than 4-12 hours

Oxygenation index

Mean Airway Pressure x FiO2 x 100/ paO2

> 35-60 for greater than 1-6 hours


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Oxygenation Failure paO2

PaO2 < 35 for 2 hours

paO2 < 50 for 12 hours

Acute decompensation

paO2 < 30 torr


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Myocardial Failure Refractory hypotension

Low cardiac output

pH


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Predicted / Measured

Outcomes Historical Mortality 80%

Mortality RCT- conventional tx 50%

ECMO mortality 15-25%


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Arterial Cannula

Venous CannulaPump

Oxygenator


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Gas

Flow


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Gas

Flow


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Gas Exchange - Oxygenator

Gas permeable surface

Blood flow

pO2 - 32Oyxgen saturation 70%

pCO2 - 45

pO2

450+Oyxgen saturation 100%

pCO2 - 40

100% FiO2

pO2 - 700+

pCo2 - 0

pO2 - lower

pCo2 - higher


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Gas Exchange Gas flow rate (sweep gas flow)

Determines CO2 removal

Gas Flow FiO2

Small effects on infant oxygen saturation

Changes paO2 of ECMO output only


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ECMO Modes Venoarterial - VA

Blood drains-venous system

Blood returns-arterial system Complete cardiopulmonary support

Venovenous - VV

Blood drains-venous system Blood returns-venous system

Pulmonary support only


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Pre ECMO Evaluation ABG, electrolytes, Ionized Ca++

Cardiac echo

Evaluate pulmonary artery pressures

Evaluate right and left ventricular function

Rule out cyanotic congenital heart disease


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Unsuspected Heart disease 2% of all ECMO for presumed respiratory

disorders

33.5% were TAPVR

10.5% Transposition of the great arteries

7.5% Ebsteins Anomaly


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Pre ECMO Evaluation Head US

Rule out severe IVH

Coagulation studies

INR, PTT, TT, fibrinogen, platelets


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ECMO Goals Maintain adequate tissue oxygenation to

allow recovery from short termcardiopulmonary failure

Adjust ventilator settings allowing for LungRest minimizing further ventilator /oxygen

induced lung injury. Not necessarily lowersettings


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Adequacy of Support - SvO2Right Atrium

Tissue

Oxygen consumption

Aorta

70%

100%

ArteryVein


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ABGPre

Post


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Adequacy of Support Tissue oxygenation

Not the same as arterial oxygenation

Oxygen Delivery Oxygen content Blood

Arterial oxygen saturation

Hemoblobin

Blood flow ECMO

cardiac


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Adequacy of Support - SvO2Vena cava

Tissue

Oxygen consumption

Ao

70%

85%


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Tissue

Oxygen consumption

Ao

55%

100%

If inadequate oxygen delivery

Anerobic metabolism

Lactic adidosis


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SvO2 Generally good indicator of adequacy of

oxygen delivery

SvO2 will drop with decreasing tissue oxygendelivery

Low SvO2

More support is needed PRBC

More flow

ECMO


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Tissue

Oxygen consumption

Ao

55%

100%


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Right Atrium

SvO2

SVC

IVC

Brain

Kidney

Intestines

Liver

Upper extremities

Heart


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SvO2 - Problems Cannot be used with VV ECMO

because of recirculation

Affected by intracardiac shunt Patent foramen ovale

Gives a macro picture of oxygen supply

and demand Ignores potential differences in regional

(organ) blood flow


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SvO2 - Alternatives Tissue oxygen saturation via near

infrared spectroscopy (NIRS)

Transcutaneous measurement Detection of blood saturation in the tissues

Primarily venous blood sampled

Can be used as a indicator of organspecific venous oxygen saturation


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VA ECMO Cannula sites

Internal jugular vein (12-10F)

Cannula tip low in the right atrium

Right common carotid artery (10-8 F) Cannula tip at the aortic arch


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Cannulation Preparation

Remote vascular access

Extension tubing on central venouscatheter and arterial catheter

Accessible easily away from the sterile

surgical field


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Medications Fentanyl 25-30 micrograms/kg

Atropine 0.01 mg/kg

Neuromuscular blocking agent Heparin 100 units/kg bolus

Needed even if continuous heparin gtt willnot be used

Ca Volume

NS, PRBC, FFP, Albumin

Prime oxygenated circuit blood


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Venous Cannula

Arterial Cannula


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PA

PA

Ao

Ao

LV

ECMO Carotid

RV

PDA


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Ventricles ECMO

Po2 - 45

Sat - 88%Po2 - 450

Sat - 100%

Po2 - 150

Sat - 100%


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Ventricles ECMO

Po2 - 450

Sat - 100%

Po2 - 450

Sat - 100%


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Ventricles ECMO

Po2 - 32

Sat - 70%Po2 - 150

Sat - 100%


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Ventricles ECMO

Po2 - 32

Sat - 70%Po2 - 150

Sat - 100%

Po2 - 70

Sat - 97%


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Ventricles ECMO

Po2 - 32

Sat - 70%Po2 - 150

Sat - 100%

Po2 - 50

Sat - 88%


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Management Fluids / Nutrition

Respiratory

Hemodynamic

Anticoagulation


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Fluids / Nutrition Obligate need to maintain intravascular

volume

90-100+ ml /kg/day

Exacerbated by capillary leak and 3rdspacing of fluid

Activation of cytokines / complement /

leukocytes Vasodilatation

Increased vascular permeability


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Na Generally total body sodium overloaded

Volume expansion with NS

Blood products Delayed Na increases with PRBC

Na/k ATPase pump turned off

High intracellular Na


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Potassium Potential problems with Hyperkalemia

Hemolysis

Circuit Stored blood

High serum K in PRBC bag

Na/K ATPase pump inactivated Hemodynamically significant only in VV

ECMO


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Calcium Hypocalcemia

Low ionozed Ca

Normal total Ca Ca binding to citrate from blood

products

Standing order for Ca Gluconate after100 ml colloid infusion


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Energy Delivery Non protein calories

50-60 kcals/kg/day

Carbohydrate Fat

No direct studies suggesting ideal mix


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Lipid infusions

Technical problems relating to the ECMO circuit

Promoting clot formation

Layering out of the emulsion

Fat deposition


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Rate ofAppearanceOf CO2

J Ped Surg 1999; 34:1086-1090

Avoid Excessive Calories


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J Ped Surg 1999; 34:1086-1090

Avoid Excessive Calories


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High Caloric intake

Increasing caloric intake associated with:

Increased amino acid oxidation (r=0.85, p


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Pulmonary Management

Aim to control pH and paCO2 only with

the ECMO circuit

Changes in sweep gas Flow Rate will

increase CO2 removal


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Pulmonary Management

Maintain lung aeration

PEEP 12-16 If lung disease

PEEP 6-8 If no lung disease

Early Surfactant replacement

Minimize ongoing lung injury - VILI

Pressure preset vent PIP - 20, RR - 10

PIP adjusted for recruitment

HFOV

Provide adequate myocardial oxygenation

FIO2 40%


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PA

PA

Ao

Ao

LV

ECMO Carotid

RV

PDA


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Rest ventilator settings

PEEP Maintaining FRC probably agood lung protective strategy

Pediatrics 1992;120:107-13

Randomized clinical trial

N = 74

High PEEP = 12-14

Low PEEP = 3-5


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Rest ventilator settings

Similar survival

High PEEP

Higher (better) CXR scores

Shorter ECMO run

97.4 vs 131.8 hours


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PEEP


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Surfactant

Alteration of surfactant metabolism

Decreased SP-A levels in trachealaspirates in ECMO patients

Increased surfactant proteins andphospholipids in correlate withimprovement in lung function


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Surfactant Replacement

J Peds 1993;122:261-268

Randomized, blinded trial

N=56 Survanta 4 doses

Placebo

Dosing at 2, 8, 20 and 32 hours


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Surfactant Replacement

In surfactant group

Faster improvement in compliance

Faster increase in SP-A No difference in CXR scores

Shorter ECMO runs

Surfactant not beneficial for CDH


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Time course

Dependant on disease process

Meconium aspiration 3-5 days

Congenital diaphragmatic hernia 7-14 days

Lung hypoplasia syndromes 14+ days


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Cardiovascular Instability

Hypotension

Hypertension

Pressure = Flow x Resistance


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Ventricles ECMO


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Hypotension

Volume -If intravascular volume depletion Increase blood drainage to the ECMO pump

Increase preload to LV/RV

Ca Myocardial contractility

Vasopressors

Increase systemic vascular resistance (SVR) Increase LV and RV


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Anticoagulation

Systemic heparin

Bolus heparin at cannulation

100 units/kg

Continuous heparin gtt

20-50 units/kg/hour

Procoagulants factors

Anticoagulant factors


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Operating Parameters

Gas Exchange

pCO2 35-45

pH 7.35-7.45 SvO2 > 70%

PaO2 50-100

SaO2 >90%


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Hemodynamics

Capillary refill time - 2 seconds

Evidence of adequate organ perfusion Urine output

No metabolic acidosis

BP- dependant on gestational age SPB > 60

Mean BP > 45-50


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Advantages of VA ECMO

Able to give full cardiopulmonary support

No mixing of arterial / venous blood

Good oxygenation at low ECMO flows

Allows for total lung rest


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VA - VV Comparison studies

J Peds Surg1993;28:530-536

Multicenter data

N=243 VA = 135

VV = 108

Similar survival

10% conversion to VA

Shorter runs

Less Neurologic complications


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ECMO

Flow 10O-120+ ml/kg/min

HgB 10-12 Platelets >100K

Anticoagulation

Variable When fully anticoagulated

ACT 180-220 seconds


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ECMO outcomes

Mostly determined by

Dx

ECMO duration Hospital course

IVH


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Jugular venous drainage

Additional drainage facilities flow

2 site venous drainage lessens recirculationon VV ECMO

Enables venous oxygen saturation monitoring

on VV ECMO

One small study suggested decreased IVH

Jugular Venous Drainage


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Jugular Venous Drainage

Cephalad Cannula

J Pediatr Surg 2004;39:672-676

Review of ELSO database

Neonatal Respiratory Failure VV ECMO1989-2001

N = 2471

96% VV double lumem alone

3.7% with jugular venous drainage Similar Outcomes


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Complications - Infants

IVH 10%

Other Bleeding 15%

Hemolysis 15%

Ultrafiltraltion/dialysis 13%

Acute Renal failure 10%

Arrhythmia 3%


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IVH

Most serious long term complication

Highest Risk period 1-5 days

Risks J Peds 1999;134:156-159

ELSO database

N=3896 9.8% ICH

30% cause of death


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Increased Risk of IVH

OR CI

< 34 wks 12.1 6.6-22.0

34-36 wks 4.1 2.9-5.836-38 2.1 1.6-2.8

Epinephrine 1.9 1.5-2.5

Sepsis 1.8 1.4-2.4pH


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IVH

No difference in

Apgar

Fetal distress IUGR

Pneumothorax

Pulmonary hemorrhage

VV ECMO

Jugular venous drainage


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IVH - Lactate

Pediatrics 1995;96:914-917

Initial 10 vs 6.4 Maximal 12.4 7.9

Predicted ICH logistic regression

None 10 40% at lactate >25

60% at lactate >40

Lactate as Predictor of


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Lactate as Predictor of

Outcome

CCM 2002;30:2135-2139

Prospective trial

2 centers

N=74

20% Early mortality

9% additional infants died before 18 mo

follow up


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Lactate

Peak lactate >25 predicted early

mortality Sensitivity 47%

Specificity 100%

Positive predictive value 100%

Negative predictive value 88%


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Lactate

Peak lactate >15 predicted adverse

outcome

Sensitivity 35% Specificity 91%

PPV 89%

NPV 38%


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Time to Give up?

Best estimate based on long runs of

congenital diaphragmatic hernia

Low additional survival past 21 days

PROPORTION OF INFANTS REMAINING ON ECMO WITH SUCCESSIVE DAY


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0.00

.10

.20

.30

.40

.50

.60

.70

.80

.90

1.00

0 10 20 30 40 50 60

DAYS ON ECMO

SURVIVORS

NON-SURVIVORS

PROPORTION OF INFANTS REMAINING ON ECMO WITH SUCCESSIVE DAY

P

E

R

C

E

N

T


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Daily Specific Survival Rate


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Second ECMO

J Peds Surg 2002;37:845-850

ELSO database

N=16,450 Second 1.22%

Third 4 infants

More complicated during second run

Survival 38% MAS still >85% survival


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Early ECMO

J Peds Surg 2002;37:7-10

Meconium Aspiration

ELSO database N=3235

Overall mortality 5.8%

Increased mortality with increasing time toECMO


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Mortality - MAS

0

1

2

3

4

5

6

7

8

9

4 days

Mortality


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ECMO Duration - MAS

0

50100

150

200

250

300350

400

450

500

4 days

Hours


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Weaning of ECMO

Assess pulmonary status

Compliance -

Vt with set Pmax, PEEP

Typical maximal vent setting Pmax 30

RR 35-40

FiO2 50%

HFOV Pulmonary hypertension

Cardiac echo

pre-post ductal saturations


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Recovery and Decannulation

Adequate gas exchange

PIP


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Weaning of ECMO

Assess hemodynamics

Ventricular funcion

Organ perfusion BP


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Weaning of ECMO - VA

ECMO flows weaned

Minimum ECMO flow 100 ml/min Risk for clot formation inceases with lower flows

(absolute flow rate) Frequent assessment of activated clotting time

(ACT) is needed

Ventilator settings at maximum Pmax to give

desired Vt Assessment of gas exchange via SaO2 and ABG

Additional preload frequently needed

Additional Ca


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VA ECMO Clamp Out

Cannula - clamped

Bridge - Opened

Stagnant blood

Tubing and cannula distal to the bridge

Intermittent flow in the cannula neededevery 5-10 minutes


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Future Management Issues

Hypothermia

Extracorporeal CPR

Follow up High incidence of late hearing loss

Routine late screening recommended

ECPR - Extraporporeal


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ECPR Extraporporeal

Cardioulmonary Resuscitation

CPR is not a contraindication for ECMO

End organ perfusion may be better post

CPR in infants treated with ECMO


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Pediatr Crit Care Med 2004;5:440-446


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Case VA ECMO for Sepsis

Infants ABG 7.34 / 40 / 350 / 19

Post oxygenator 7.34 / 40 / 450 / 19

Preoxygenator 7.30 / 46 / 20 / 19 CXR - White out

Systemic oxygen delivery is:

Low - pvO2 is low, SvO2 is low

Cardiac output is: Low - paO2 in infant is similar to the post

oxygenator paO2


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Case VA ECMO for Sepsis

Infants ABG 7.36 / 40 / 52 / 24

Post oxygenator 7.39 / 36 / 450 / 24

Preoxygenator 7.30 / 44 / 40 / 24

Systemic oxygen delivery is: High - PvO2 is high, SvO2 is high

Cardiac output is:

Good - large gradient between infant ABG and

post oxygenator gas Mixing of LV and ECMO output

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Extra corporeal membrane oxygenation