Evaluation of the microcirculation during extracorporeal membrane-oxygenation

Extracorporeal membrane oxygenation (ECMO) provides pulmonary and circulatory support in critically ill patients (Cardiopulmonary Resuscitation, Acute Respiratory Distress Syndrome, or low output syndrome). Hemodynamic parameters are used for evaluation of the macrocirculation, while the microcirculation is monitored by blood-lactate as a surrogate parameter. We evaluated the microcirculation by orthogonal polarization spectral imaging in a patient during ECMO support. This method was initially proposed to quantify changes of microcirculation in patients with septic shock. However, we were able to non-invasively monitor microcirculatory changes at the bedside during temporary intentional arrest of ECMO due to an exchange of the oxygenator. Using a computerized analyzation model, the flow after ECMO stop in vessels (10-100 microm) in the sublingual mucosa was acutely absent or intermittent, respectively. 120 s after restart, microflow was improved with new ECMO settings compared to baseline, while macrocirculation with a mean arterial pressure of 75 mmHg was present after 60 s. The application of orthogonal polarization spectral imaging might be a valuable technique for evaluation of the microcirculation during extracorporeal circulation. It is rapidly implementable, can be used in vivo, and no invasive probes are required.