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During refractory cardiogenic shock and cardiac arrest, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is used to restore a circulatory output. However, it also impacts significantly arterial oxygenation. Recent guidelines of the Extracorporeal Life Support Organization (ELSO) recommend targeting postoxygenator partial pressure of oxygen (P POST O 2 ) around 150 mmHg. In this narrative review, we intend to summarize the rationale and evidence for this P POST O 2 target recommendation. Because this is the most used configuration, we focus on peripheral VA-ECMO. To date, clinicians do not know how to set the sweep gas oxygen fraction (F S O 2 ). Because of the oxygenator's performance, arterial hyperoxemia is common during VA-ECMO support. Interpretation of oxygenation is complex in this setting because of the dual circulation phenomenon, depending on both the native cardiac output and the VA-ECMO blood flow. Such dual circulation results in dual oxygenation, with heterogeneous oxygen partial pressure (PO 2 ) along the aorta, and heterogeneous oxygenation between organs, depending on the mixing zone location. Data regarding oxygenation during VA-ECMO are scarce, but several observational studies have reported an association between hyperoxemia and mortality, especially after refractory cardiac arrest. While hyperoxemia should be avoided, there are also more and more studies in non-ECMO patients suggesting the harm of a too restrictive oxygenation strategy. Finally, setting F S O 2 to target strict normoxemia is challenging because continuous monitoring of postoxygenator oxygen saturation is not widely available. The threshold of P POST O 2 around 150 mmHg is supported by limited evidence but aims at respecting a safe margin, avoiding both hypoxemia and severe hyperoxemia., (© 2022. The Author(s).)

Although being a potential major source of infection in extracorporeal membrane oxygenation (ECMO) patients, data regarding cannula-related infections (CRI) remain scarce. We therefore aimed at describing the epidemiology of CRI among critically ill patients supported by ECMO. Between October 2017 and November 2019, adult patients supported by either venoarterial (VA), venopulmonary arterial, or venovenous (VV) ECMO for more than 24 hours were prospectively enrolled. When CRI was suspected, cannula swab and subcutaneous needle aspirate samples were obtained for microbiological culture. Cannula tips were systematically sent for culture at the time of ECMO removal. Primary end-point was CRI, which was defined by sepsis or local sign of cannula infection and at least one positive culture among swab, subcutaneous needle aspirate or tip. Multivariate analysis was performed to identify risk factors of CRI. Hundred patients were included, including 77 VA, 12 venopulmonary arterial, and 11 VV ECMO. Cannula-related infections were diagnosed after a median duration of ECMO of 10 [7-13] days. Rate of CRI was 24%, including 10% with bacteremia. Most frequent involved pathogens were Enterobacteriaceae (n = 14), Enterococci (n = 8), and coagulase-negative Staphylococci (n = 7). By multivariate analysis, diabetes and ECMO duration were independently associated with CRI., Competing Interests: Disclosures: The authors have no conflicts of interest to report., (Copyright © ASAIO 2021.)

Aims: The role of extracorporeal membrane oxygenation (ECMO) remains ill defined in pulmonary embolism (PE). We investigated outcomes in patients with high-risk PE undergoing ECMO according to initial therapeutic strategy., Methods and Results: From 01 January 2014 to 31 December 2015, 180 patients from 13 Departments in nine centres with high-risk PE were retrospectively included. Among those undergoing ECMO, we compared characteristics and outcomes according to adjunctive treatment strategy (systemic thrombolysis, surgical embolectomy, or no reperfusion therapy). Primary outcome was all-cause 30-day mortality. Secondary outcome was 90-day major bleeding. One hundred and twenty-eight patients were treated without ECMO; 52 (mean age 47.6 years) underwent ECMO. Overall 30-day mortality was 48.3% [95% confidence interval (CI) 41-56] (87/180); 43% (95% CI 34-52) (55/128) in those treated without ECMO vs. 61.5% (95% CI 52-78) (32/52) in those with ECMO (P = 0.008). In patients undergoing ECMO, 30-day mortality was 76.5% (95% CI 57-97) (13/17) for ECMO + fibrinolysis, 29.4% (95% CI 51-89) (5/17) for ECMO + surgical embolectomy, and 77.7% (95% CI 59-97) (14/18) for ECMO alone (P = 0.004). Among patients with ECMO, 20 (38.5%, 95% CI 25-52) had a major bleeding event in-hospital; without significant difference across groups., Conclusion: In patients with high-risk PE, those with ECMO have a more severe presentation and worse prognosis. Extracorporeal membrane oxygenation in patients with failed fibrinolysis and in those with no reperfusion seems to be associated with particularly unfavourable prognosis compared with ECMO performed in addition to surgical embolectomy. Our findings suggest that ECMO does not appear justified as a stand-alone treatment strategy in PE patients, but shows promise as a complement to surgical embolectomy.

We report a case of a refractory cardiogenic shock secondary to myocardial infarction in a 70-year-old patient requiring femoral venoarterial extracorporeal membrane oxygenation (VA-ECMO). At initial transesophageal echocardiography, the venous cannula tip was seen in the inferior vena cava (IVC), but not in right atrium. On day 8, ultrasonic examination identified that the end of the venous cannula was in the hepatic vein (HV). Despite such malposition, no disturbance in extracorporeal membrane oxygenation (ECMO) venous return was observed. Moving or replacing the cannula was considered a high-risk maneuver potentially resulting in hepatic laceration with hemoperitoneum. Because of adequate venous drainage, allowing sufficient blood flow, venous cannula repositioning was delayed until day 10, when a ventricular defect was repaired and ECMO was weaned off. At the time of VA-ECMO implantation, the venous cannula has to be positioned in the right atrium using real time echo monitoring. Visualization of the guide wire in the IVC but not in the right atrium is insufficient to ensure appropriate venous cannula positioning. Indeed, either accidental catheterization or cannula migration into the HV is possible during ECMO. Health care professionals dealing with ECMO have to be aware of this possible malposition, to correct it and prevent insufficient venous drainage or traumatic complications.