Improving ECMO therapy: Monitoring oxygenator functionality and identifying key indicators, factors, and considerations for changeout.

INTRODUCTION: The optimal timing for extracorporeal membrane oxygenation (ECMO) circuit change-out is crucial for the successful management of patients with severe cardiopulmonary failure. This comprehensive review examines the various factors that influence the timing of oxygenator replacement in the ECMO circuit. By considering these factors, clinicians can make informed decisions to ensure timely and effective change-out, enhancing patient outcomes and optimizing the delivery of ECMO therapy. METHODOLOGY: A thorough search of relevant studies on ECMO circuits and oxygenator change-out was conducted using multiple scholarly databases and relevant keywords. Studies published between 2017 and 2023 were included, resulting in 40 studies that met the inclusion criteria. DISCUSSION: Thrombosis within the membrane oxygenator and its impact on dysfunction were identified as significant contributors, highlighting the importance of monitoring coagulation parameters and gas exchange. Several factors, including fibrinogen levels, pre and post-membrane blood gases, plasma-free hemoglobin, D-dimers, platelet function, flows and pressures, and anticoagulation strategy, were found to be important considerations when determining the need for an oxygenator or circuit change-out. The involvement of a multidisciplinary team and thorough preparation were also highlighted as crucial aspects of this process. CONCLUSION: In conclusion, managing circuit change-outs in ECMO therapy requires considering factors such as fibrinogen levels, blood gases, plasma-free hemoglobin, D-dimers, platelet function, flows, pressures, and anticoagulation strategy. Monitoring these parameters allows for early detection of issues, timely interventions, and optimized ECMO therapy. Standardized protocols, personalized anticoagulation approaches, and non-invasive monitoring techniques can improve the safety and effectiveness of circuit change-outs. Further research and collaboration are needed to advance ECMO management and enhance patient outcomes.

Clinical Evaluation of Measuring the ACT during Elective Cardiac Surgery with Two Different Devices.

Unfractionated heparin is the mainstay of anticoagulation during cardiac surgery on cardiopulmonary bypass (CPB) due to its low cost, quick onset, and ease of reversal. Since over 30 years, the activated clotting time (ACT) has been used to assess the level of heparin activity both before and after CPB. We compared two different methods of measuring the ACT: i-STAT, which uses amperometric detection of thrombin cleavage, and Hemochron Jr, which is based on detecting viscoelastic changes in blood. We included 402 patients from three institutions (Papworth Hospital, Cambridge, UK; Groote Schuur, Cape Town, South Africa; University Hospital Basel, Basel, Switzerland) undergoing elective cardiac surgery on CPB in our study. We analyzed duplicate samples on both devices at all standard measuring points during the procedure. The correlation coefficient between two Hemochron and two i-STAT devices was .9165 and .9857, respectively. The within-subject coefficient of variation (WSCV) ranged from 8.2 to 13.6% for the Hemochron and from 4.1 to 9.1% for the i-STAT. We found that the number of occasions where one of the duplicate readings was >1,000 seconds while the other was below or close to the clinically significant threshold of 400 seconds were higher for the Hemochron. We found the i-STAT to systematically return higher measurements. We conclude that the i-STAT provides a more reliable test for heparin activity and assesses safe anticoagulation during cardiac surgery on pump. The fact the that the i-STAT reads higher than the Hemochron leads to the recommendation to validate the methods against each other before changing devices.