Management of Infants requiring Venovenous ECMO

Sixto F. Guiang, III

Dept. of Pediatrics

University of Minnesota

Neonatal ECMO = 73 % of all ECMO

VV ECMO = 20% of all Neonatal Pulmonary

University of MichiganJAMA 2000;283:904-908

N= 1000 Newborns N=586 Survival 88% MAS 98% CDH 68% Others 84-93% 90% veno-venous 9% IVH

VV ECMO Respiratory Mode for all ages

Infants 20% of all Respiratory ECMO Approximately 800 cases / yr

Pediatric 28% of all Respiratory ECMO Approximately 200 cases / yr

Pediatric VV ECMO Pediatr Crit Care Med 2003;4:291-298 Single Center 1991-2002 N = 82 ECMO for Respiratory Failure

Venovenous 83% Venoarterial 17%

Unable to place VV 43%

Pediatric VV ECMO Venovenous

Dx ARDS RSV bronchiolitis Penumonia

Outcomes Lower degree of respiratory failure Shorter ECMO (212 hour vs 350 hours) Higher survival (81% vs. 64%)

Pediatric VV ECMO

Pediatr Crit Care Med 2003;4:291-298

Infusion limb

Drainage limb

Inclusion / Exclusion Guidelines- Same as VA 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 ventilation with

high ventilatory settings

Oxygenation FailureCriteria - VA and VV 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

Oxygenation FailureCriteria - VA and VV paO2

PaO2 < 35 for 2 hours paO2 < 50 for 12 hours

Acute decompensation paO2 < 30 torr

Myocardial Failure - VA Only Refractory hypotension

Low cardiac output

pH <7.25 for 2 hours or greater

Uncontrolled metabolic acidosis secondary to hemodynamic insufficiency

Cardiac arrest - CPR

Additional Exclusion Criteria - Venovenous ECMO Severe LV dysfunction Severe hypotension Cannulation during CPR

Desire to not have heparin Bleeding

Additional Exclusion Criteria - Venovenous ECMO

Use of vasopressors is NOT a contraindication for VV ECMO

Isolated RV failure is NOT a contraindication for VV ECMO

Vasopresor - VV ECMO ASAIO Journal 2003;49:568-571 Neonatal ECMO-VA and VV N = 43 Quantified inotropic support - Index 1 point = 1mcg/kgmin

Dopamine Dobutamine

1 point = 0.01 mcg/kg/mon Epinephrine Norepinephrine

ASAIO Journal 2003;49:568-571

ASAIO Journal 2003;49:568-571

ASAIO Journal 2003;49:568-571

Infants with Inotropic Score > 10

ASAIO Journal 2003;49:568-571

ECMO Goals - VA and VV Maintain adequate tissue oxygenation to

allow recovery from short term cardiopulmonary failure

Adjust ventilator settings allowing for Lung Rest minimizing further ventilator /oxygen induced lung injury. Not necessarily lower settings

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

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

Disadvantages of VA ECMO Ligation of the right carotid artery

Nonpulsatile arterial blood flow

Suboptimal conditions for LV function Low preload High afterload High wall stress Low coronary oxygenation

Disadvantages of VA ECMO

Systemic emboli Air thrombus

Advantages of VV ECMO No ligation of carotid artery

Normal pulsatile blood flow

Optimize LV performance More preload Less afterload Better coronary oxygenation Less ventricular wall stress

No systemic emboli

Disadvantages of VV ECMO Need a functioning LV Mixing of blood lower arterial

saturation Need increased ECMO flow Need higher hemoglobin

Need to place a larger cannula More difficulty monitoring adequacy of

oxygen delivery Recirculation of ECMO flow

Disadvantages of VV ECMO May need to convert to VA

Need to be fully heparinized Cannula cannot be heparin bonded

VV ECMO -Double lumen Newborns

>90% of VV ECMO - Double lumen 12F and 15F OriGen

Pediatric 35% of VV ECMO -double lumen

18F - largest OriGen cannula 65% internal jugular, femoral, sapphenous

VV ECMO -Double lumen

Cannula site

Internal jugular vein (15F double lumen- preferred)

Cannula tip low in the right atrium

Drainage

Endhole

High lateral RA

Low lateral RA

Infusion

Mid Medial RA

Optimal Cannula Placement Adequate size Correct depth

Low Right Atrium Correct Rotation

Label visible Drainage limb (Blue) posterior Infusion limb (Red) anterior Vertical orientation Head - midline

No Kinks

Recirculation Oxygenated ECMO blood returning to

the ECMO circuit immediately after infusion

Recirculation factors Head /cannula position

Changes with head rotation Changes in lung volume / relative position of the

heart and cannula

ECMO flow

Right atrial size / intravascular volume

RV contractility

ECMO Flow reads 200

ECMO blood flow to baby - 160

ECMO Flow reads 500

ECMO blood flow to baby - 250

ECMO Flow -Recirculation More ECMO flow will always increase

recirculation

More ECMO flow may either Increase blood flow to baby Decrease blood flow to baby

VA ECMO ECMO flow rate is proportional to the level of

support

More flow More support Always advantageous if more flow is possible More ECMO flow will always increase SvO2

Pulmonary Support - VV Net ECMO blood flow of infant = measure

ECMO flow - recirculation flow

ECMO flow (flow probe) DOES NOT indicate level of support

SvO2 DOES NOT reflect level of systemic oxygen delivery

Circulatory Support Net flow to baby assessed by

Infant color Infant arterial saturation and PaO2

Assessment of Recirculation More recirculation if

Decreasing baby arterial sat or PaO2 Increasing SvO2 on ECMO circuit Decreasing color difference on drainage

and infusion limbs of circuit

Reducing Recirculation Adjusting relative cannula position

Head position Lung inflation

Decrease ECMO flow Increase intravascular volume Increase RV contractility

Volume Vasopressors Pulmonary vasodilators

VV - VA Conversion Needed if 10-15% of cases

Hemodynamic support is inadequate Respiratory support is inadequate

More problematic when ultrafiltration is used

VV ECMO - Specific Issues ECMO Prime

Must have added heparin Must have Ca added Ionized Ca on circuit must be

checked prior to cannulation Potassium must be checked

Heparin If no heparin added

Addition of Ca binds citrate of blood products

Loss of anticoagulant activity Acute clotting of the entire circuit Need to prime another circuit

Calcium If no calcium added

Acute hypocalcemia - Ca binds to citrate of blood products

Loss of LV and RV contractility Acute hypotension Cardiac arrest

Potasium If potassium in prime is not checked

Possible higher serum K from the stored PRBC

Acute hyperkalemia Arrythmia Cardiac arrest

Head / Cannula Position Distal tip low in RA Head in the midline with vertical orientation of

the drainage and infusion limbs RA drainage ports

Lateral Infusion ports

Medial

Keys to Management

VV ECMO- DL Need to think in terms of NET blood flow

to the baby Cannot quantify NET flow SvO2 is not indicative of adequacy of

systemic oxygen delivery Indirectly assessed with SaO2 and

PaO2 on the infant

To Improve oxygenation Give PRBC Increase ECMO flow Decrease recirculation

Check cannula position Increase ntravascular volume Increase RV contractility

Rest Ventilator Settings Pressures - similar to VA FiO2 - able to wean to RA frequently

Better myocardial oxygenation via ECMO flow than VA

Jugular venous drainage 11% of all double lumen VV Small study suggested decrease IVH

Reduced cerebral venous pressure Advantage

Additional drainage facilities flow 2 site venous drainage lessens recirculation

on VV ECMO Improved oxygen delivery Enables venous oxygen saturation monitoring

on VV ECMO

Jugular Venous DrainageCephalad Cannula J Pediatr Surg 2004;39:672-676 Review of ELSO database Neonatal Respiratory Failure VV ECMO

1989-2001 N = 2471

96% VV double lumem alone 3.7% with jugular venous drainage

Similar Outcomes

Operating Parameters SaO2 - 85-95% PaO2 40-65 torr Blood pressure - similar to VA ECMO flows - 130-150+ ml/kg/min HgB 12-15 g/dl

Weaning of ECMO - VV No clamp out needed Increase ventilator Decrease sweep gas flow rate and FiO2 Sweep gas flow can be completely stopped

SvO2 will reflect mixed venous saturation No recirculation

GasGasFlowFlow

NO GasNO GasFlowFlow

VV ECMO Outcomes Generally slightly better than VA, but

slightly different patient populations Hemodynamically more stable Less exposure to CPR Better survival Shorter duration of ECMO Conversion VV to VA

12%

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