BackgroundThe rate, prognostic impacts, and predisposing factors of major vascular complications (MVCs) in patients underwent venoarterial extracorporeal membrane oxygenation (VA-ECMO) by surgical cut-down are poorly understood. The purpose of this study was to identify these parameters in adult VA-ECMO patients.MethodsAdult postcardiotomy cardiogenic shock (PCS) patients receiving VA-ECMO by femoral surgical cut-down cannulation from January 2004 to December 2015 were enrolled in this study. Patients were separated into two groups depending on the presence of MVCs. Multivariate logistic regression was performed to identify factors independently associated with MVCs.ResultsOf 432 patients with PCS treated with VA-ECMO, 252 patients (58.3%) were weaned off VA-ECMO and 153 patients (35.4%) survived to discharge. MVCs were seen in 72 patients (16.7%), including bleeding or hematoma in the cannulation site (8.6%), limb ischemia requiring fasciotomy (8.6%), femoral artery embolism (0.7%), and retroperitoneal bleeding (0.7%). The rate of survival to discharge was 16.7 and 39.2% in patients with or without MVCs, respectively (p < 0.001). Obesity, concomitant with intra-aortic balloon pump (IABP), Sequential Organ Failure Assessment (SOFA) score at 24 h post-ECMO, and hemostasis disorder were shown to be associated with MVCs. MVCs were an independent risk factor for in-hospital mortality by multivariate analysis (odds ratio 3.91; 95% confidence interval, 1.67–9.14; p = 0.013).ConclusionsMVCs are common and associated with higher in-hospital mortality among adult PCS patients receiving peripheral VA-ECMO support. The obesity, concomitant with IABP, SOFA score at 24 h post-ECMO, and hemostasis disorder were independent risk factor of MVCs.

IntroductionDifferential hypoxia is a pivotal problem in patients with femoral veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) support. Despite recognition of differential hypoxia and attempts to deliver more oxygenated blood to the upper body, the mechanism of differential hypoxia as well as prevention strategies have not been well investigated.MethodsWe used a sheep model of acute respiratory failure that was supported with femoral VA ECMO from the inferior vena cava to the femoral artery (IVC-FA), ECMO from the superior vena cava to the FA (SVC-FA), ECMO from the IVC to the carotid artery (IVC-CA) and ECMO with an additional return cannula to the internal jugular vein based on the femoral VA ECMO (FA-IJV). Angiography and blood gas analyses were performed.ResultsWith IVC-FA, blood oxygen saturation (SO2) of the IVC (83.6 ± 0.8%) was higher than that of the SVC (40.3 ± 1.0%). Oxygen-rich blood was drained back to the ECMO circuit and poorly oxygenated blood in the SVC entered the right atrium (RA). SVC-FA achieved oxygen-rich blood return from the IVC to the RA without shifting the arterial cannulation. Subsequently, SO2 of the SVC and the pulmonary artery increased (70.4 ± 1.0% and 73.4 ± 1.1%, respectively). Compared with IVC-FA, a lesser difference in venous oxygen return and attenuated differential hypoxia were observed with IVC-CA and FA-IJV.ConclusionsDifferential venous oxygen return is a key factor in the etiology of differential hypoxia in VA ECMO. With knowledge of this mechanism, we can apply better cannula configurations in clinical practice.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0791-2) contains supplementary material, which is available to authorized users.