Date post: | 13-Dec-2015 |
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Vascular Access & Cannulation
Dr Osama BawazirAssistant Professor , Consultant Pediatric surgeon
FRCSI, FRCS(Ed), FRCS (glas), FRCSC,FAAP,FACS.
• ECMO is a supportive measure, which can be instituted as an urgent, semi elective or elective procedure
• Time in relation to the event is the limiting factor when going through the assessment cascade in order to accomplish a successful result
• PRE-ECMO ASSESSMENT
• CANNULATION
• INITIATION AND MAINTENANCE OF ECMO
• EVALUATION
Introduction
CANNULATIONCANNULATION
The establishment and maintenance of
adequate vascular access is essential
for ECMO
CANNULATIONCANNULATION- 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
CANNULATIONCANNULATION For each modality, there are
different kinds and sizes of cannulae that can be used
Target activated clotting time (ACT) should be accomplished first before ECMO (heparin 100 units/kg) 3 minutes before cannulation.
Consent GA
Guidelines for Cannula size Guidelines for Cannula size
Weight (Kg)Venous cannula arterial cannula
2-4 8-14 8-10
5-15 15-19 12-15
16-20 19-21 15-17
21-35 21-23 17-19
35-60 23 19-21
>60 23 21
Poiseuille’s LawPoiseuille’s Law
• Poiseuille's law: In an artificial system, flow through a cylindrical tube or any segment of a tube is directly proportional to ΔP, the driving pressure along the tube, and the fourth power of the radius, r. Flow is inversely proportional to L the length of the segment and to η, the viscosity of the liquid. The proportionality constant is π/8.
Cannula ConsiderationCannula Consideration
• Venous cannula should be with the largest lumen and shortest length possible (gravity).
• Venous cannula should have side holes.
• M-number
• Resist kinking
• The smallest double lumen cannula is size 12 F ( for V V ecmo in neonate)
CANNULATIONCANNULATION• Veno-Venous (V-V) ECMO
- Mainly used for respiratory support (ARDS & Congenital Diaphragmatic Hernia)
- V-V ECMO provides adequate oxygenation and CO2 removal
- The venous access can be established by using the system in one site, or two different sites
CANNULATIONCANNULATION
• Veno-Arterial (VA) ECMO
provides cardiac as well as respiratory
support and is mainly used for post op
cardiac case
(V-V) ECMO Advantage offer (V-A) ECMO
• Eliminate the potential for arterial embolization and ischemia
• Arterial ligation or repair is unnecessary
• Improve the blood flow and oxygenation to pulmonary circulation.
• No hemodynamic effects
CANNULATION TECHNIQUE
• Open
• Semi-open
• Percutaneous
CANNULATIONCANNULATIONInternal jugular vein
CANNULATIONCANNULATION
Subclavian vein & Right atrium
CANNULATIONCANNULATION
Femoral vein
CANNULATIONCANNULATION
One site
- A double lumen cannula is inserted into the internal jugular vein
- Only one site for venous access
CANNULATIONCANNULATION
Two different sites
CANNULATIONCANNULATION
• Veno-Arterial (VA) ECMO
provides cardiac as well as respiratory support and is
mainly used for post op cardiac case
CANNULATIONCANNULATION
Internal jugular vein and the common
carotid artery
CANNULATIONCANNULATION
Right atrium and ascending aorta
CANNULATIONCANNULATION
Femoral vein and artery
CANNULATIONCANNULATION
A Left atrial pressure line can be utilized to
monitor the LA pressure
CANNULATIONCANNULATION
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
- Standby preprimed pump will be kept in ICU
CANNULATIONCANNULATION PROBLEMS PROBLEMS
• Threading the venous catheter
• Vein division
• Proximal vein lost in mediastinum
• Lack of venous return
• Intrathoracic vein perforation
ComplicationComplication
• Vascular injury( tear, intimal dissection, perforation).
• Obstruction (kinking, positional).
• Misplacement( AI, afterload LV failure).
• Bleeding.• Recirculation.
Thank You