1. ECMO for Severe Cardiac and Respiratory Failure in Adults
Ann Petlin, RN, MSN, CCRC-CSC, CCNS, PCCN
Clinical Nurse Specialist, Cardiothoracic Surgery
Barnes-Jewish Hospital, St. Louis, MO 63110
March 2016

2. Objectives
Describe the medical indications for the use of extracorporeal membrane oxygenation (ECMO)
Differentiate between V-V and V-A ECMO
Explain how ECMO works to promote gas exchange
Discuss the nursing implications and care of the patient on ECMO

3. The heart-lung machine first used at the Mayo Clinic in March 1955.
Where ECMO came from
The heart-lung machine first used at the Mayo Clinic in March 1955.
The screen oxygenator is the rectangular box on the top of the machine.

4. What is ECMO Pump and oxygenator
Supports cardiac and/or respiratory function
Days to weeks
Extended use of cardiopulmonary bypass outside the OR

5. Indications for Adult ECMO
Lung and/or heart disease that is
Acute
Life-threatening
Potentially reversible
Unresponsive to conventional therapy
Cardiomyopathy, cardiogenic shock, post-cardiotomy
Severe ARDS, pneumonia, bridge to transplant
Patient has no contraindications to anticoagulation

6. Conventional heart support in shock
Oxygen, pain relief, rest, fluid balance optimal
Inotropic medications, vasodilators, Ca+2 blockers
Temporary pacing to optimize heart rate, IABP
Optimize acid-base and electrolyte balance
Address inadequate tissue metabolism

7. Conventional lung support in ARDS
Mechanical ventilation with PEEP cm
Low tidal volumes with permissive hypercapnea
Adequate FiO2 (< 60%); avoid oxygen toxicity
Monitor peak and plateau inflation pressures
Advanced ventilator modes to increase alveolar recruitment (PC, APRV, Inverse I:E)
Prone position
Optimize fluids, pulmonary vasodilators

8. Contraindications / Exclusions
Absolute
Acute cerebral damage
Uncontrolled sepsis
Metastatic cancer or other terminal disease
Relative (may improve with improved flow)
Acute renal failure
Liver failure
Older age
Others: uncontrolled bleeding, aortic insufficiency, little salvageable myocardium, pulmonary HTN

9. ECMO System Vascular access Centrifugal pump
V-A or V-V
Centrifugal pump
CentriMag at BJH
Flow 2 – 6 L/min
Membrane oxygenator with integral heat exchanger
Heater keeps blood at 37o C for optimal combining of O2 with Hgb
Oxygen / air blender / analyzer
System fits on portable cart
Pump
Membrane oxygenator
Vascular access
Air- O2 blender

10. Cannulation Inflow = flow of blood from the pt to the device
Outflow = flow of blood from the device to the pt
Cannula technique depends on:
Type of support needed
Patient size
Clinical situation

11. Cannulation Closed chest – peripheral vessels access
One cannula for inflow; another for outflow

12. Cannulation Closed chest – peripheral access
Dual-lumen access cannula (Maquet Avalon Elite)
Link to You Tube video clip: “Maquet Avalon Elite Catheter” (non-USA version)

13. Dual Lumen Rt IJ catheter

14. Cannulation
Open chest – Cannulas exit near sternum or below ribs; Sternum may be open or closed

15. Pump to Provide Flow
Console & Monitor
Pump Motor

16. Centrifugal Pump Magnet in motor spins pump head
Centrifugal forces propel blood
Tornado or vortex effect
Pressure low in apex of pump; creates vacuum; removes blood from patient
Pressure positive at sides and bottom of pump; returns blood to the patient
Preload dependent – adequate blood volume
Afterload sensitive – blood pressure management

17. Oxygenator Gas exchange device Adds O2, removes CO2
Driven by gradients (high pressure to low)
Surface area = 1.8 M2
Blood access in/out
Gas inlet
Heat exchanger

18. Surface area for gas exchange Adult lung vs. ECMO oxygenator
Adult lung surface area ~ 75 M2
ECMO
Membrane
ECMO Membrane = 1.8 M2

19. ECMO Principle
ECMO works by diffusion of gases (O2, CO2) across a semi-permeable membrane
Typically the patient remains on a ventilator to help minimize alveolar atelectasis
Occasionally patients are extubated while on ECMO
Blood side
Membrane
Gas side

20. ECMO Gas Exchange Oxygen diffuses into the blood
Oxygen concentration higher on gas side of membrane
Net diffusion of O2 into the blood
FiO2 adjusted to keep O2 sat ~ 95%
Carbon dioxide diffuses out of the blood
Liter flow of the Air-O2 mixture
Speed of the gas in liters/minute determines how quickly CO2 is “swept” out of the blood
Net diffusion of CO2 out of the blood
Liter flow adjusted to keep PaCO2 within normal (35-45)

21. CentriMag Consoles
2nd generation CentriMag
1st generation CentriMag

22. Maquet ECMO Membrane Dark, de-oxygenated blood (right) ;
Oxygenated blood (left)

23. ECMO Membrane & Pump

24. ECMO Heaters

25. Gas flow meters, O2 blender and O2 monitor
Flow meter – verify gas is flowing (meter set above 0)
Flow meters control the gas flow rate (speed of the gas).
The O2 blender controls the oxygen concentration delivered to the oxygenator.
Mini Ox – monitors delivered O2 %
Blender – verify FiO2 is set at prescribed %

26. Portable ECMO Cart

27. Extracorporeal Membrane Oxygenation V-V ECMO
Respiratory failure unresponsive to conventional management
V-V ECMO provides mainly lung support
Venous exit cannula from a major vein
Venous return cannula to a major vein
Variety of cannula options
Decreases pulmonary resistance
Standard ventilator management
Problem:
Allows oxygenated blood to recirculate through ECMO circuit
Some patients may need a switch to V-A ECMO

30. Extracorporeal Membrane Oxygenation V-A ECMO
Combined cardiopulmonary failure
V-A ECMO supports both heart and lungs
Venous cannula removes blood from vena cava
Rt internal jugular
Femoral vein
Common iliac
Arterial cannula returns blood to central circulation
Aorta
Femoral artery
Variety of cannula options
Higher oxygenation possible than with V-V ECMO
Problem:
Higher risk of systemic emboli
Reduces blood flow through the coronary arteries; might need IABP to provide flow to coronaries

31. V-A ECMO Cannulation Options
Central cannulation
Femoral cannulation
Problem with peripheral VA ECMO:
Lower body receives better perfusion
Possible poor perfusion of coronary and cerebral vessels
Oxygenated blood returned to aorta so lungs get little O2 rich blood -> may exacerbate lung ischemia

32. Peripheral V-A ECMO Problems
Left ventricular distention
ECMO does not directly decompress the left ventricle
Typically ~ 80% of blood thru ECMO circuit
~ 20% of blood thru left ventricle
Without adequate ejection, blood will accumulate in under pressure
Can lead to severe pulmonary edema and fatal pulmonary hemorrhage
Prevention: inotropes to maintain LV ejection, minimize afterload (manage BP), IABP
Treatment: atrial septostomy or LV vent to allow left atrial blood to flow into the ECMO circuit
Perfusion to foot with femoral artery cannulation
Femoral perfusion cannula to reduce limb ischemia risk

33. Peripheral V-A ECMO Problems
Aortic root thrombus
Peripheral ECMO blood travels retrograde up the descending aorta until it meets blood ejected by the left ventricle
Some degree of stagnation may occur → thrombus (stroke risk)
Avoid by ensuring native left ventricular ejection
Cerebral hypoxia
Fully saturated blood from ECMO circuit meets blood ejected from native left ventricle
Location of the “mixing point” depends on amount of ECMO support and degree of LV ejection
Severe myocardial dysfunction → mixing point in the proximal aorta
As heart function improves →mixing point migrates more distally
Hypoxic blood may perfuse proximal aorta, coronary and cerebral arteries
Femoral ABG shows fully saturated blood; Rt radial ABG shows hypoxia
Treatment: Adjust ventilator with ↑FiO2, PEEP
Run You Tube video clips: VenoArterial ECMO Mayo Clinic (7:35)

34. ECMO Goals
Maintain adequate gas exchange with lowest FiO2 and airway pressures
Typical ventilator settings:
FiO2 titrated to keep PaO mm Hg; SpO2 ~ 95%
Respiratory rate ~ 8 breaths / min
Tidal volume 5-8 ml / Kg
PEEP 5 cm H2O
Airway pressures below ~ 35 cm H2O
During weaning, ventilator re-set to support native blood flow and oxygenation through lungs

35. Delineation of Roles
Surgeon – surgical management; cannulates the patient; manipulates, adjusts and changes ECMO components; prescribes interventions
Perfusionist – primes circuits and supports patient during initial set-up; available on call after patient is stable; checks circuit daily; consults with team
Nursing – manages the patient and monitors ECMO; identification of patient and circuit problems
ICU Team – medical management of patient; prescribes interventions

36. ECMO Management
↓ in arterial saturation and ↓ PaO2 = need to ↑ECMO blood flow
Make small changes at each interval
Example: 4 LPM to 4.5 LPM
Monitor ABGs, SpO2, ET CO2
Add volume to increase cardiac output
Typically do not make changes to the mechanical ventilator until patient is ready to attempt weaning from ECMO

37. ECMO Problems Bleeding Clotting Infection
Re-exploration to find source and decide treatment
Factors: Prolonged CPB time, anticoagulation, thrombocytopenia, hemolysis due to the device
Clotting
Anticoagulation to decrease the risk of clot formation
Infection
Multiple invasive lines, cannulas, immobility
Scrupulous attention to infection control practices
Cannula dislodgement = EMERGENCY
Turn off pump, clamp cannulas close to pt
Prepare to open chest or return to OR

38. ECMO Problems Hypothermia Neurologic assessment Skin care
Risk because patient’s blood outside body
Interferes with normal cellular function
Neurologic assessment
High risk of cerebral emboli
Recommend daily awakening to assess neuro function
Skin care
Patients susceptible to complications of bed rest
Emotional support / education needs
Family also your patient; enlist chaplain & social worker

39. Weaning of ECMO
Generally try for at least hrs of stability, or longer depending on the reason for ECMO
Assess readiness to wean:
Decrease flows; observe hemodynamic waves; TEE imaging
MDs manipulate pumps; perfusionist might assist
Evaluate arterial line for LV function; PAWP for LA function
Evaluate PAP for RV function; CVP for RA function
Increases in CVP, PAP, PAWP or ↓BP indicate pt not ready to wean

40. Mobilizing the ECMO Patient
Types of cannulas determine level of activity
Central or subclavian cannulas – ROM and OOB
Peripheral cannulas – ROM and in-bed activities
Careful protocol enlisting support of nursing, perfusionist, physical therapy with MD order
Patient & family education essential
Only perfusionists do critical hook ups
Secure the cannulas
Adequate gas supply
Console battery charged; two working cell phones if leaving ICU

41. Mobilizing the ECMO Patient

42. “Carla”
Woman; early 30’s; early Sept fever of undetermined cause; worsening oxygenation; admit to local hospital Early Oct transferred to BJH for ECMO Lungs did not improve; listed for lung transplant Gradually stronger with rehab; remained on V-A ECMO Dec 24 – lung transplant

43. Outcomes

44. Summary
ECMO when needed in select patients for respiratory or cardiorespiratory support
Patient management
Monitor progress toward goals
Assess for complications
Include family in care, planning and transplant evaluation
Evolving technologies
Increased pt activity
Improve physiology for transplant success

45. Summary Critical care nurses play a central role
Providing direct patient care
Coordinating care among the team members
Optimal patient outcomes depend upon carefully monitoring effectiveness and complication of ECMO