Strategy and tips for cannulation:
We designed a process of in-situ VV-ECMO cannulation based on the layout
of our intensive care unit (ICU) where patients with refractory
respiratory failure are routinely hospitalized (fig. 1). We utilize a
portable fluoroscopy bed which is placed to the side of the ICU bed
(fig. 2). After moving the patient from the ICU to the fluoroscopy bed,
the medical equipment is positioned around the patient to allow
convenient access to the right side of the neck as the cannula insertion
site (fig. 3). The procedure is completed under sterile conditions with
fluoroscopic guidance. Fluoroscopic guidance represent our preferred
imaging method since it may offer the highest level of safety (9,11).
However, in the absence of conditions allowing routine use of
fluoroscopy at the bedside, the procedure can also be safely performed
with transthoracic echocardiogram (TTE) to confirm guidewire and cannula
positioning (9, 17-19). Appropriate positioning of the wire can be
confirmed with subcostal views, making sure that the guidewire is
advanced into the retro-hepatic inferior vena cava (IVC) (9, 18-23).
Alternatively, imaging by portable chest X-ray can also be used to spot
check guidewire and cannula position (16).
Cannulation best practices using our approach are listed in table 1. We
always use real-time ultrasound visualization for the puncture of the
IJV. The patient is maintained in slight Trendelenburg position for the
entire duration of the procedure to reduce the risk of venous
air-embolism. The guidewire is advanced deep into the retrohepatic IVC
and its position is confirmed by imaging. We used the standard packaging
of the Avalon Elite® venous cannula kit (0.038” x 210 cm change
guidewire) in all cases (table 2). After serial dilation of the skin and
soft tissue at the cannula insertion site, the IJV is cannulated with 10
Fr through 30 Fr dilators. The cannula is inserted under imaging
guidance ensuring no resistance is encountered while the catheter is
advanced through the right atrium into the IVC. The cannula is connected
to the ECMO circuit with meticulous de-airing and is secured to the skin
once final manual manipulation is made to ensure adequate extracorporeal
blood flow and desired arterial oxygenation (table 1).