Discussion
In our experience, the procedure of bedside VV-ECMO cannulation was safe
and effective. We had only one case of failed IJV single-cannula
insertion which required veno-arterial cannulation using the common
femoral artery and vein due to anatomic constraints. All procedures were
performed in the ICU under fluoroscopic and echocardiographic guidance.
Our set-up allowed the efficient utilization of fluoroscopy by using a
mobile, x-ray compatible bed (figures 1,2)). We selected the use of a
bicaval dual-lumen cannula whenever indicated to facilitate adequate
ECMO flow and optimize blood oxygenation by reducing “recirculation”
(5,12,24). Although there is a lack of randomized trials comparing the
effectiveness of the single dual-lumen versus a double venous
cannulation strategy, clinical data and experimental studies show at
least comparable flow-parameters and clinical results (24, 25).
Nonetheless, the location of the cannula on the side of the neck, as
compared to the groin, provides more opportunity for patient
mobilization and may offer significant advantages in light of the fact
that VV-ECMO support is often required for a considerable length of
time.
The benefits of in-situ ECMO cannulation, not only in terms of
potentially expediting the timing of initiation of therapy and
decreasing the hazard of transporting the patient to the procedural
location, appears of crucial importance during the COVID-19 pandemic in
the extreme cases of respiratory decompensation and refractory hypoxemia
which may benefit from VV-ECMO support. Avoidance of transporting the
patient out of the ICU to reach the designated cannulation location
reduces the risk of SARS-CoV-2 virus transmission to other patients and
healthcare providers while also decreasing the risk of environmental
contamination inevitably associated with the transportation process, and
possibly decreasing unnecessary personal-protective-equipment (PPE)
usage outside of the ICU. The use of fluoroscopic guidance has
represented the standard for our protocol, however cannulation can also
be safely completed using echocardiographic imaging with TTE or even
using portable chest x-ray, which can be both routinely arranged at any
healthcare facility. No matter of the imaging technique used, single
venous cannulation with bicaval dual-lumen catheter remains a highly
demanding procedure with risk of life-threatening complications, so that
it should be performed by experienced operators in highly specialized
centers (21,23,26).