Overview
Blood which recirculates through the circuit of a veno-venous Extracorporeal Membrane Oxygenation (V-V ECMO) does not contribute to the systemic oxygenation of a patient on V-V ECMO and is called the recirculation fraction (Rf). Theoretically, the optimization of ECMO blood flow is possible using Rf measurements.
A prospective, observational study will be performed measuring the Rf of total ECMO blood flow in patients with acute respiratory distress syndrome (ARDS) on V-V ECMO with an ultrasound dilution technique.
ECMO blood flow will be optimized by reducing ECMO blood flow in accordance with the measured Rf as long as systemic oxygenation is not compromised.
Description
Based on data from the 'Blood Recirculation and vvECMO' trial (ClinicalTrials.gov ID: NCT03200314) (i.e. an expected frequency of successful blood flow reduction of 66.7%), using a one-sample Chi square test, a two-sided type-1 error of 5%, a power of 80%, a total of 68 patients is needed to show that the proportion of patients with a secure ECMO blood flow reduction is greater than 50%. Presumably, 136 Patients have to be included into the trial to study 68 patients with a relevant Rf since not all patients on V-V ECMO suffer from a high Rf.
Eligibility
Patients aged 18 years or older requiring veno-venous ECMO for treatment of refractory hypoxemia in ARDS.