Coagulation abnormalities in patients with COVID-19 on venovenous ECLS increased risk for technical complications and support times but had no impact on survival.

BACKGROUND: Patients with severe coronavirus disease-19 (COVID-19)-associated acute respiratory distress on venovenous extracorporeal lung support (V-V ECLS) showed a high incidence of vascular as well as ECLS-related thrombotic complications. The latter may influence the outcome of the patients. METHODS: This is a retrospective monocentric study on prospectively collected data of technical complications including 69 adult COVID-19 patients on V-V ECLS (ECLS Registry, March 2020 until April 2021) without and with system exchanges. Alterations in ECLS-specific data, hemolysis, coagulation, and hemostasis parameters were analyzed. RESULTS: Every second COVID-19 patient on V-V ECLS developed technical complications. Optimized ECLS management at our ECLS center reduced cases of acute clot formation (pump head thrombosis, acute oxygenator thrombosis) (17%), and allowed early identification of progressive clotting processes (worsened gas transfer, coagulation disorder) (14%, 54%) with a significant overhang of hyperfibrinolysis (37%). Although COVID-19 disease and technical complications caused the prolonged length of stay at the intensive care unit and ECLS support times, the proportion of successful weaning and survival rates were comparable with patients without system exchange. CONCLUSION: The survival of ECLS patients with COVID-19 was independent of the requirement for system exchange due to technical-induced coagulation disorders. Close monitoring for circuit clotting is mandatory in COVID-19 patients and is one prerequisite for successful organ support in these difficult patients.

Flow dynamics of different adult ECMO systems: a clinical evaluation.

Membrane oxygenator (MO) failure is a known hazard during venovenous extracorporeal membrane oxygenation (v-v ECMO) therapy. Knowledge about technical and performance details of different ECMO systems (Maquet, Rastatt, Germany; Medos, Stolberg, Germany; Sorin, Modena, Italy) licensed for adults with acute lung failure might improve their handling. This retrospective study comprises 186 adult patients (Regensburg ECMO Registry) treated with v-v ECMO. Flow dynamic data were used to analyze the performance of different blood pumps, cannula types, and MOs to maintain an adequate blood flow (1-5 L/min). Usage of the Medos ECMO system in critically ill patients required a higher pump speed and generated a higher pressure drop across the MO (dpMO), however, without an increase in free plasma hemoglobin. The dpMO depended on the type of MO and increased with blood flow as expected. Type-specific normal values are reported. A distinct increase in dpMO above normal values within 1 day required an immediate MO exchange. This was an infrequent technical complication (3%). Finally, pressure-flow performance of single dual-lumen cannulas (27 Fr) was comparable with small single-lumen cannulas (15 Fr), without an increased risk of technical-induced hemolysis. Despite different performances, all current commercially available adult v-v ECMO systems produce adequate blood flow without an increased risk in technical-induced hemolysis. Familiarity with the specific properties of individual systems allows early detection of technical complications. Additionally, the choice of an adequate cannula requires a closer consideration of the individual patient situation.