Neurological Considerations
The use of a combination bilateral cerebral oximetry/anesthetic depth monitor during hybrid ECMO allows for monitoring of anesthetic depth and ensuring adequate cerebral oxygenation. Anesthetic depth must be monitored and titrated, due to the use of inhaled anesthetic in both the mechanical (hybrid ECMO) and native (lungs via the anesthesia machine) cardiac outputs to assure both adequate depth of anesthesia and to provide theoretical protection against the development of PGD. Hybrid ECMO cannulation can be either central or peripheral, and the use of cerebral oximetry monitoring provides information regarding both cerebral perfusion and oxygenation in hopes to avoid differential hypoxemia (north-south syndrome) associated with peripheral VA-ECMO.1
Comments
We previously described a hybrid ECMO-CPB circuit that provides lung transplantation teams the ability to provide ECC via either VA-ECMO or CPB.2 While the goals for intraoperative management of ECMO include maintenance of systemic perfusion and controlled reperfusion of the newly implanted lungs, achieving the balance between native and mechanical cardiac outputs can be challenging. Despite these challenges, successful implementation of VA-ECMO is important as it can provide theoretical attenuation of the ischemic-reperfusion injury and improved perioperative outcomes.5 As summarized in Table 1, the use of an organ system-based approach based on best evidence and anesthetic monitors that are multi-faceted yet complementary in design has enabled use of the hybrid ECMO circuit for intraoperative ECC since September 2017. Future concepts of investigation for intraoperative management of the hybrid circuit include the utility of goal-directed perfusion using DO2and TEE-guided quantification of native cardiac output through the implanted grafts. Appropriately designed studies, both within our institution and in coordination with other centers, are needed to assess the efficacy of our approach for lung transplantation.