ecmo presentation final
TRANSCRIPT
PHYSIOLOGY ,CANNULATION AND
MONITORING OF VENO-ARTERIAL ECMO
Dr.Manoj.P. Lead Consultant Cardiovascular and Thoracic
Surgeon Aster Medcity
Extra corporeal Life Support is achieved by
- Draining venous blood
- Removing CO2
- Adding oxygen
- Returning to circulation
- Through either a vein or artery
Types of ECMO
ECMO can be categorised according to the circuit used
• Veno-arterial - VA ECMO provides both gas exchange and circulatory support (Heart & Lung failure)
• Veno-venous –VAECMO allows gas exchange only (Isolated Lung failure)
Modes of ECMO
Veno -arterial (VA)ECMO
•Provides both respiratory and cardiac support
•Blood is drained from venous system and given to arterial system.
Low flow veno-arterial ECMO is a transitory form of ECMO support in which small cannulae (quicker to insert) are inserted. It is an emergent resuscitative intervention, (Ecmo CPR)
VA ECMO – Technical Specifications
Peripheral-FA, pump outflow is retrograde, admixing at arch level.
If Respiratory failure co exists, heart pumps poorly oxygenated blood to coronaries and brain, while ECMO supports body distal to Aortic arch.
For this reason R Radial line is prudent
Mechanical ventilation continued to maintain Sao2 of blood ejected from LV at 90%
First successful ECMO patient, 1971
J Donald Hill MD and Maury Bramson BME, Santa Barbara, Ca, 1971. (Courtesy of Robert Bartlett, MD)
First Neonatal ECMO survivor..
Esperanza, Age 1 day 1975
Esperanza, age 21
FROM THIS
TO THIS
Advantages and Disadvantages
Advantages Disadvantages
Both cardiac and pulmonary support Cannulation of major artery and sacrifice of one carotid in newborn
More experience Poor coronary and pulmonary perfusion
Instant hemodynamic support Systemic thromboembolism
No recirculation Nonpulsatile flow
Right and left heart Myocardial stunning and LV distension
Increased incidence of neurological events
ECMO ??????
• Several considerations must be weighed
- Likelihood of organ recovery- Cardiac re-recovery- Disseminated malignancy- Advanced age- Graft vs . Host disease- Known severe brain injury- Unwitnessed cardiac arrest- Aortic dissection or aortic incompetence
• The physiologic goal is to improve tissue oxygen delivery , remove CO2 and allow normal aerobic metabolism whilst the lung rests
• ECMO circulation: - Dual circulation - Nonpulsatile flow
Dual circulation
• Native circulation + ECMO circulation
• Sometimes Results in North South syndrome if the return cannula is in femoral artery
• In most cases ECMO provides 60-80 % of CO resulting in a discernible pulse contour
• Reduces preload• Increases afterload Myocardial
stunning • Left sided decompression• Use of inodilators
In Veno Arterial ECMO
• Perfusate saturation is 100%• Without lung function LV saturation=RV saturation• ABG reflects Perfusate+RV saturation• If 50% blood flows through lungs,50% through
oxygenator –O2 saturation of arterial blood becomes 90%
Increase in Systemic PO2 may result from..
• Improved lung function at constant flow
• Increased ECC flow at constant CO
CO2 removal..
• Mainly depends on oxygenator surface area and sweep gas flow rate
• Independent of blood flow
• Moderately depends on inlet CO2
During Veno arterial ECMO..
• O2 consumption decreases ( catecholamines reduced,less metabolic stress)
• Arterial saturation >95 % and flow adjusted to maintain arterial/venous saturation
• Bleeding Decreased venous return Decrease in flow Transfusion
• Without lung function and ejection of heart arterial
saturation decreases
• Knowledge of the physiology of ECMO support the management of ECMO patient
• O2 content is of utmost importance in the physiologic management of critically ill patients
• DO2/VO2 ratio is reflected by mixed venous saturation - most important monitor in critically ill patients
CANNULATION
The establishment and maintenance of adequate vascular access is essential
for ECMO
CANNULATION
- Patient age and size- Underlying disease & condition- Cause of the cardiorespiratory compromise- Type of support:
• Veno-venous (VV) ECMO • Veno-arterial (VA) ECMO
- Time of the event in relation to the peri-operative period
- Location
CANNULATION
• For each modality, there are different kinds and sizes of cannulae that can be used
• Target ACTshould be accomplished before ECMO (heparin 100 units/kg)
3 minutes before cannulation.
Cannula Consideration
• Venous cannula should be with the largest lumen and shortest length possible.
• Venous cannula should have side holes.• M-number• Resist kinking• Smallest double lumen cannula is size 12 Fr ( for V V ecmo in neonate)
Veno-Arterial (VA) ECMO
Provides cardiac as well as respiratory support and is
mainly used for post op cardiac case
Cannulation can either be..
• Through neck vessels(RCC artery and RIJV and or an additional vein)
• Central cannulation
or
• Cannulation of groin vessels
Access and return cannula sites
Access Return
RA Aorta
Femoral Vein Femoral Artery
Subclavian Vein Axillary artery
Internal Jugular Vein Carotid artery
CANNULATION TECHNIQUE
• Open• Semi-open • Percutaneous
CANNULATION
• In central cannulation Aorta and RA are cannulated
• LV decompression is important :Can be done either by creating an
atrial communication or by a Left atrial vent
CANNULATION
Right atrium and
Ascending aorta
CANNULATION
A Left atrial vent line can be utilized to monitor the LA
pressure
CANNULATION
Internal jugular vein and the common
carotid artery
Veno arterial access via the neck vessels
CANNULATION
Femoral vein and
Femoral artery
Venoarterial access via the femoral vessels
Peripheral Femoral Cannulation – VA ECMO
Femoral artery cannulation:
• Chances of distal limb ischemia• Distal perfusion catheter is commonly
used
Distal Leg Perfusion 7/9 Fr Cannula
CANNULATION
-In situations where ECMO support is anticipated
-Chest will be left open and covered by a Silastic patch
-Purse-string sutures will be left snared in place
CANNULATION PROBLEMS
• Threading the venous catheter• Vein division• Proximal vein lost in
mediastinum• Lack of venous return• Intrathoracic vein perforation
Complications
• Vascular injury( tear, intimal dissection, perforation).
• Obstruction (kinking, positional).
• Misplacement( AI, afterload LV failure).
• Bleeding.
Monitoring
• Success lies with vigilant monitoring which helps in early
recognition and diagnosis of problems and timely and
accurate action
• Monitoring includes: -Clinical parameters-Biochemical and
Laboratory parameters-Radiologic monitoring-Circuit monitoring
Clinical parameters
• Vital parameters(ECG rhythm,Pulse rate,Blood Pressure ,Temperature , and respiratory rate)
• Arterial and venous saturation(MAP and mixed venous saturation)
• Daily Echocardiography• Right hand saturation gives hints regarding
coronary perfusion
• Hematological parameters(CBC,HCT 35-40%,Plasma Free Hemoglobin <0.1g/dl)
• If possible cerebral oxygenation with NIRS• EtCO2• RBS : 80-140 mg/dl• ABG and RBS to be done every 4-6 hours• Vascular and neurological status• Urine output and urine colour
Coagulation Monitoring
•Pre ECMO ACT 300 seconds•On ECMO –Check ACT 2 hourly till
ACT drops to 200 seconds•Maintenance with ACT 160-200 seconds•ACT to be repeated every 6-8 hours•aPTT : 60-70 seconds
Circuit monitoring..
• Circuit blood flow• Circuit gas flow• Circuit pressure• Circuit integrity
These variables should be monitored continuosly
Factors affecting Circuit Blood flow
Increased Blood flow Decreased Blood flow
Increased RPM Decreased RPM
Decreased Resistance :Vasodilation :Improved arterial cannula position
Increased Resistance :vasoconstriction :Kinking of tubing :Improper cannula position
Increased preload :Increased filling :Improved venous cannula position
Decreased preload :Hypovolemia :Improper cannula position :Kinking of tubing
Circuit Pressure
• Pre pump pressure: too much negative pressure results in Hemolysis, cavitation, endothelial damage of Right atrium and vena cava
• Reasons : Hypovolemia, Improper catheter placement,
Inadequate cannula size.
•Pre membrane pressure•Post membrane pressure•Transmembrane pressure
Circuit integrity
• Check for : Clot : Air : Leak
• Pump is checked for abnormal noise or crack
Clot in the oxygenator
Other things to be checked regularly.
• Insertion site/dressing security
• Functioning of heat exchanger
• Access line for kinking/movement
Thank You