Dr. Martin Ruß and his critical care team at the Intensive Care Clinic of Charité - Medical University and Institutes of Health in Berlin, Germany, report a case in which they used the Transonic ELSA Monitor to optimize oxygen flow in a 10-year-old ECMO patient.

The child suffered from extra-pulmonary acute distress syndrome (ARDS) caused by postoperative sepsis and massive transfusion. Veno-venous (V-V) ECMO was initiated in the pediatric intensive care unit (ICU) of the Charité hospital. Cannulas were inserted into the femoral and jugular veins to deliver oxygenated blood to the child’s lungs from the ECMO circuit. However, after ECMO was initiated, oxygen in the pulmonary artery only increased from 44 mmHg to 66 mmHg. Consequently, the child was transferred to Dr. Ruß’s intensive care clinic.

There, recirculation was measured with the Transonic Extracorporeal Life Support Assurance (ELSA) Monitor using the saline ultrasound dilution technique. Recirculation was high: the first measurement registered 78% and the second 65%. Effective flow was low: 680 mL/min with the first measurement which increased to 1280 mL/min with the second measurement.

The position of the two cannulas in the thorax was also visualized with CT scans. The clinicians postulated from the high recirculation, low effective ECMO flow, and the CT scans that the return cannula was inserted in so far that it caused direct jetting of blood towards the inferior vena cava which, in turn, caused the recirculation.

In an attempt to reduce recirculation, the cannula was pulled back approximately 2 cm. Measurements were repeated with the ELSA Monitor. The results showed that recirculation had dropped to 25%, effective ECMO blood flow increased to 1800 mL/min and pulmonary artery oxygen levels increased to 187 mmHg.

From this experience, the critical care team concluded that, when initiation of high flow V-V ECMO did not sufficiently support systemic oxygenation in their 10-year old patient, measurements of recirculation with the ELSA Monitor, imaging techniques and applied ECMO physiology did guide them to change the cannula position and thus optimize oxygenation and provide protective ventilation of the lungs of the child.

REFERENCE

Ruß M et al, “Optimization of V-V ECMO circuit determined by blood recirculation measurements improved systemic oxygenation in a 10-year old patient,” Poster Presentation at the 5th International Symposium on ARDS, Berlin, Germany, 2019. (Transonic Reference # ELS10566AH)