Vascular Access & Cannulation Dr Osama Bawazir Assistant 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

Introduction PRE-ECMO ASSESSMENT CANNULATION INITIATION AND MAINTENANCE OF ECMO EVALUATION

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 activated clotting time (ACT) should be accomplished first before ECMO (heparin 100 units/kg) 3 minutes before cannulation. Consent GA

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 >60 21

Poiseuille’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 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)

CANNULATION 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

CANNULATION 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

CANNULATION Internal jugular vein

Subclavian vein & Right atrium CANNULATION Subclavian vein & Right atrium

CANNULATION Femoral vein

CANNULATION One site A double lumen cannula is inserted into the internal jugular vein Only one site for venous access

CANNULATION Two different sites

CANNULATION Veno-Arterial (VA) ECMO provides cardiac as well as respiratory support and is mainly used for post op cardiac case

Internal jugular vein and the common carotid artery CANNULATION Internal jugular vein and the common carotid artery

Right atrium and ascending aorta CANNULATION Right atrium and ascending aorta

Femoral vein and artery CANNULATION Femoral vein and artery

A Left atrial pressure line can be utilized to monitor the LA pressure CANNULATION A Left atrial pressure line can be utilized to monitor the LA pressure

In situations where ECMO support is anticipated 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 Standby preprimed pump will be kept in ICU

CANNULATION PROBLEMS Threading the venous catheter Vein division Proximal vein lost in mediastinum Lack of venous return Intrathoracic vein perforation

Complication Vascular injury( tear, intimal dissection, perforation). Obstruction (kinking, positional). Misplacement( AI, afterload LV failure). Bleeding. Recirculation.

Thank You