Fall Workshop presentation - ECMO

Report
ECMO 101: An Introduction for
Critical Care Nursing
Jody Huber, MD FAAP
Pediatric Critical Care
Sanford Children’s Hospital
11/4/14
Objectives
• Understand the physiology of the ECMO
circuit.
• Know basic indications for ECMO in infant,
pediatric and adult populations.
• Understand benefits and risks of
anticoagulation associated with ECMO.
• Understand monitoring of an ECMO patient.
• Know how to respond to ECMO
complications/emergencies.
Outline
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What is ECMO?
How does it work
Indications
Modalities: V-V vs. V-A
Anticoagulation
Monitoring
Complications
Case Study #1
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8 y/o known asthmatic w/ URI 2 days PTA
Night PTA used Albuterol inhaler X 10
Given 1 dose oral steroid in AM
Family drove to ER
BG: 7.17/77 in ER
Neuro intact in ER
Ketamine X 1 + BiPAP  rapid deterioration
SQ Epi X 3, continuous Albuterol,
Terbutaline bolus & gtt started in ER
Case Study #1
• Obtunded in PICU, poor air movement
bilaterally
• BG: 6.83/172/210/-6
• Intubated, sedated, and paralyzed
• Auto PEEP 18
• Terbutaline 10 mcg/kg/min, Solu Medrol 2
mg/kg, Albuterol 20 mg/hr, Ketamine
• Anesthesia consulted for initiation of
Isoflurane
Case Study #1
• Isoflurane started  massive vasopressor
support required
• pH continued between 6.9 – 7.14 with CO2 139207 while intubated w/ Isoflurane x several hours
• Should we try ECMO for this patient?
• Can we support this patient?
• How should we support this patient?
Case Study #2
• 13 y/o w/ TGA s/p arterial switch and PV
replacement . . . presents w/ abdominal pain,
lethargy, low grade fever & vomiting x 6 days
• 2/2 blood cultures (+) S. aureus 3 days PTA
• Admitted locally for hypotension &
thrombocytopenia
• Transferred to Sanford Children’s for
worsening hypotension
Case Study #2
• Echo: EF 71% on left, significantly decreased RV
systolic and diastolic function, RV hypertrophy,
moderate TR w/ TR jet of 150 mmHg, RV to PA
conduit hypoplastic, free PI, large VSD patch, no
vegetations seen
• CTA chest – possible vegetation on PV, multiple
microemboli in lung
• Meropenem & Vancomycin
• ABG 7.04/27/95/-22
• WBC 36.4K (left shift), Plts 76K
• HCO3 10, Alb 1.4, Lactic acid 3.3
Case Study #2
• Multiple fluid boluses
• CV support: Epi 0.4 mcg/kg/min; NE 0.7 mcg/kg/min;
Hydrocortisone
• Mottled, cold, diaphoretic, not tolerating position
changes, desaturations
• Should we try ECMO for this patient?
• Can we support this patient?
• How should we support this patient?
What is ECMO/ECLS?
• Extracorporeal Membrane Oxygenation
• Extracorporeal Life Support
• Temporary support of heart and/or lung function
using mechanical devices
• Used in infants, children and adults for cardiac
and/or respiratory failure
• First used by Bartlett (surgeon from Univ.
Michigan) in late 1970’s in neonates with
respiratory failure
How Does ECMO Work?
• 2 Modalities:
– V-V (veno-venous)
– V-A (veno-arterial)
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Mechanical blood pump
Gas exchanger
Heat exchanger
Circuit tubing
(PVC-based plastic compound)
Lequier, 2013.
Cannula Placement
Monitoring
• Continuous values:
– Venous oxygen saturation
• Oxygen extraction (cardiac output)
• V-V will have higher SVO2  recirculation
– Arterial blood gas
– Arterial oxygen saturation
– ETCO2 from airway  native lung function
– Vital signs
• Anticoagulation:
– ACT hourly & platelets every 8-12H
– Monitor for clots in circuit
Van Meurs, 2005; Lequier, 2013.
Monitoring
• Blood flow = ml/kg/min
• Circuit pressures
– Venous access pressures – before centrifugal pump
• Avoid excessive suction, adequate venous drainage & circuit
volume
• Bladder
– Pre-membrane pressure
– Post-membrane pressure
• Both pressures rise  obstruction to inflow cannula
• Transmembrane pressure rise  increased resistance in
oxygenator
• Pre/post oxygenator blood gas
• Bubble detector by oxygenator
Lequier, 2013; Butt, 2013.
Continuous SVO2, ABG, SaO2
Pre and post-filter pressures
Flow rate
Drawing of ACT
Pumps
• Must provide appropriate flow for patient
– 75-150 ml/kg/min = infants & children
• Roller pumps
– Heavy motor, tubing can wear/rupture in pump head, no
limit to infusion pressure, risk of blowout
– If pump flow exceeds venous drainage flow – bladder
collapses and pump stops
• Centrifugal pumps
– Replacing roller pumps
– Light & small motor, components don’t wear out, infusion
pressure limited by rpm, circuit rupture uncommon
– Potential for inadequate venous drainage
– Afterload sensitive
Lequier, 2013; Butt, 2013
Roller vs. Centrifugal Pump
Oxygenators
• Add O2 & remove CO2
• Hollow fiber PMP (polymethylpentene)
oxygenators primarily used today
– Extremely efficient at gas exchange
– Minimal plasma leakage
– Low resistance to blood flow
– Pediatric & adult sizes
– Integrated heat-exchange device
Lequier, 2013.
Goals of Support
• Adequate blood flow for cellular metabolic needs
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100-150 ml/kg/min (higher with sepsis)
SVO2 70%
Lactic acid
Capillary refill
Urine output
• Adequate oxygenation
– SaO2 > 75%
– Hgb > 12 gm/dl
– pCO2 40 mmHg
• Prevention of complications from other therapies
– Lung damage from VILI
– Cardiac injury from high-dose inotropes/vasopressors
Van Meurs, 2005; Butt, 2013.
Indications
• General: Acute, severe, reversible cardiac or
respiratory failure when risk of dying from
primary disease despite optimal conventional
treatment is high
Van Meurs, 2005.
Indications: Neonates
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PPHN (Persistent Pulmonary Hypertension)
MAS (Meconium Aspiration Syndrome)
CDH (Congenital Diaphragmatic Hernia)
Sepsis/pneumonia
Air leak
Van Meurs, 2005; Dalton, 2012
Van Meurs, 2005.
Indications: Children
• Severe acute respiratory failure
• Sepsis
• Cardiac failure
– Congenital heart disease (post-operative)
– Cardiomyopathy
– Myocarditis
• ECPR – ECMO initiated while undergoing CPR
• Hypothermia re-warming
• Therapeutic hypothermia
Van Meurs, 2005; Dalton, 2012.
Indications: Adult
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Graft failure after cardiac or lung transplantation
Cardiac failure
Shock
Severe respiratory failure
Hypothermia re-warming
Therapeutic hypothermia
Dalton, 2012.
Dalton, 2012
Contraindications
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Recent intracranial hemorrhage
Embolic stroke
Established renal failure
Prolonged ventilation
Immunocompromised*
– Underlying cancer or immune defect w/ good
long-term outcome
– Stem cell transplant  poor outcome
Dalton, 2012, Jaquiss, 2013.
Veno-Venous ECMO
• Veno-venous ECMO = replaces function of
lungs only
• NO EFFECT ON HEMODYNAMICS
• Oxygenated blood returns to vein & travels to
heart to be circulated systemically
• Recirculation = oxygenated blood returns to
ECMO circuit
Veno-Venous ECMO
• What to do with the ventilator?
– Low TV, High PEEP, low PIP’s, low FiO2, low rate,
longer iT
– LET THE LUNG REST!
• Bronchoscopy
• Surgical airway intervention
Veno-Arterial ECMO
• Veno-arterial ECMO = replaces function of
both heart and lungs
• Oxygenated blood returns to artery (bypasses
heart)
V-V vs. V-A
V-A
V-V
Systemic Perfusion
Circuit flow and native CO
Native CO only
Arterial BP
Pulse contour dampened
Pulse contour full
CVP
Not helpful
Accurate guide of
volume status
Typical blood flow for full gas
exchange
80-100 ml/kg/min
100-120 ml/kg/min
Arterial oxygenation
Controlled by ECMO flow
80-95% common at
max flow
Van Meurs, 2005.
Timing of ECMO
• Decrease in survival after 14 days of preECMO mechanical ventilation (60%  38%)
• Pre-ECMO oxygenation index (OI)
• End-organ dysfunction
• Lactate > 25 mmol/L
Rehder, 2013.
Case Study #1
• Should we try ECMO for this patient?
– Yes – reversible condition in otherwise healthy
child
• Can we support this patient?
– Yes – hemodynamically stable but unable to clear
CO2
• How should we support this patient?
– Veno-venous ECMO (no need for cardiac
support)
Case Study #2
• Should we try ECMO for this patient?
– Yes – child with repaired CHD, was previously
doing well before acute illness
• Can we support this patient?
– Yes but hemodynamically unstable
• How should we support this patient?
– Veno-arterial ECMO due to poor RV function &
catecholamine resistant septic shock
Anticoagulation
• Blood contacting non-physiologic surface =
thrombosis involving a fibrin and platelet layer
• Slow flow = more time for clot to form (peds)
• Fast flow = less time for clot to form (adults)
• Heparin infusion – most reliable &
controllable anticoagulant
• How does Heparin work?
Van Meurs, 2005; Annich, 2013.
Anticoagulation
• Monitoring
– ACT = Activated Clotting Time
• Only POC test for anticoagulation
• Measures clotting of whole blood
– Anti-Xa
• Measure of Heparin effect
– aPTT
• Plasma test activated by phospholipids
– Thromboelastography
• Analyze different phases of anticoagulation
• Newer methods:
– Heparin-bonded circuits
• Goals:
– Bolus w/ initiation of ECMO (50-100 U/kg)
– Goal ACT 180-200 seconds
– Measure AT levels?
Van Meurs, 2005; Annich, 2013.
Machine Emergencies/Complications
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Thrombosis – most common
Cannula problems
Air embolism
Oxygenator failure
Tubing rupture
Heat exchanger malfunction
Pump failure/cutting out
– Hand crank!
• Accidental decannulation
Van Meurs, 2005; Butt, 2013.
Van Meurs, 2005.
What to do in an Emergency?
Van Meurs, 2005.
Patient Emergencies/Complications
• Bleeding
– Local vs. systemic
– Systemic anti-fibrinolytics (Amicar)
• Neurologic – hemorrhage or ischemic stroke
– HUS/HCT
– Avoid HTN
• Infection
• Hemolysis
• Acute kidney injury
Van Meurs, 2005; Butt, 2013.
Is Nursing Care Different?
• Respiratory
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Lung rest – low TV, high PEEP, low rate, low FiO2
Routine suctioning
Have emergency ventilator settings available
Equal breath sounds on assessment
• Neurological
– Neuro exam including pupils
– Minimize sedation if possible
• Cardiac
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Avoid high-dose vasopressors
Avoid HTN
Perfusion/pulses
Pulse pressure may be minimal if on full V-A support
Van Meurs, 2005; Schwartz, 2013.
Is Nursing Care Different?
• Urine output/fluid balance
– Fluid removal is a balance
– Venous drainage dependent on preload – watch
venous pressure
– “chattering”
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Skin care
Bleeding/oozing
ECMO is keeping patient alive – vigilance
If patient comes off circuit  job is to care for
patient & let ECMO tech manage circuit
• Psychosocial support
Van Meurs, 2005; Schwartz, 2013.
Prognosis/Outcomes
Dalton, 2012.
Prognosis/Outcomes
• Survival:
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Neonatal CDH 51%
Neonatal sepsis: 72%
Pediatric sepsis: 40%
Pediatric Immunodeficiency: 31%
Adolescent sepsis: 31%
• Long-Term Outcomes:
– Neonatal: 6-13% severe neurological deficits
– Pediatric respiratory failure: 16% severe
neurological deficits
Van Meurs, 2005; Rehder, 2013.
Follow-up Case Study #1
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Veno-venous (Avalon cannula) ECMO x 7 days
CO2 cleared quickly
Extubated after 10 days
Doing well
Followed closely with Peds Pulmonology
Follow-up Case #2
• Veno-arterial ECMO
• Repair of Pulmonary valve after clearance of
endocarditis
• In rehabilitation now but overall doing well
What we did not discuss . . .
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Inflammation secondary to ECMO
Weaning off ECMO
Decannulation
Ethics
References
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Van Meurs, et al. ECMO: Extracorporeal Cardiopulmonary Support in Critical
Care, 3rd Ed. 2005.
Rehder KJ et al. Extracorporeal Membrane Oxygenation for Neonatal and
Pediatric Respiratory Failure: An Evidence-Based Review of the Past Decade
(2002-2012). Pediatr Crit Care Med. 2013; 14:851-861.
Dalton, HJ et al. Extracorporeal life support: An update of Rogers’ Textbook of
Pediatric Intensive Care. Pediatr Crit Care Med. 2012; 13:461-471.
Jaquiss, RD et al. An overview of mechanical circulatory support in children.
Pediatr Crit Care Med. 2013; 14:S3-S6.
Lequier, L et al. Extracorporeal Membrane Oxygenation Circuitry. Pediatr Crit
Care Med. 2013; 12:S7-S12.
Butt W et al. Clinical Management of the Extracorporeal Membrane Oxygenation
Circuit. Pediatr Crit Care Med. 2013; 14:S13-S19.
Annich, G et al. Anticoagulation for pediatric mechanical circulatory support.
Pediatr Crit Care Med. 2013; 14:S37-S42.
Schwartz S et al. Medical and nursing care of the child on mechanical circulatory
support. Pediatr Crit Care Med. 2013; 14:S43-S50.
Thank you!

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