OBJECTIVES: To explore the potentials of microcirculatory assessments for predicting outcome of patients treated with extra corporeal membrane oxygenation for cardiogenic shock. METHODS: Eight patients with acute cardiogenic shock treated with ECMO and eight healthy controls were examined with skin vital microscopy and laser Doppler perfusion measurements. RESULTS: Three patients died on ECMO (group 1). Five patients were successfully weaned off ECMO (group 2). Four patients were discharged from hospital and one died after successful weaning from bleeding complications. Patients surviving ECMO (group 2) had microcirculatory findings comparable with healthy controls. Patients in group 1 showed major skin microvascular pathology: pericapillary bleedings (n = 1), pericapillary dark haloes (n = 2) and capillary micro thrombi (n = 1). As compared with survivors they had lower functional capillary density (FCD) (n = 3), higher heterogeneity of functional capillary density (n = 3) and significantly reduced capillary mean flow-categorical velocity (n = 2). Laser Doppler measurements in group 1 had non-significant lower laser Doppler flux values as compared with survivors and controls. CONCLUSION: Skin microvascular pathology as detected with video microscopy (pericapillary bleedings or haloes, microthrombi/capillaries with "no flow", low FCD with high spatial distribution heterogeneity or low mean flow-categorial velocity) seems to be associated with poor prognosis.