Thorac Cardiovasc Surg 2011; 59 - V83
DOI: 10.1055/s-0030-1269020

Lower flow during minimized extracorporeal circulation does not impair cellular metabolism

J Gehron 1, RK Weimer 1, M Scheffler 2, A Böning 1
  • 1Universitätsklinikum Gießen und Marburg GmbH Standort Gießen, Klinik für Herz-, Kinderherz- und Gefäßchirurgie, Gießen, Germany
  • 2Universitätsklinikum Gießen und Marburg GmbH Standort Gießen, Klinik für Anästhesie und Operative Intensivmedizin, Gießen, Germany

Objective: During minimized extracorporeal circulation often a lower cardiac index than during conventional extracorporeal circulation has to be tolerated. Whether cellular function is impaired by this lower flow remains unclear. Lactate measurement during bypass may serve as an indicator of changed cellular energy metabolism.

Methods: During a prospective randomized trial to compare blood consumption and inflammatory response between minimized (Terumo ROCSafe®, MECC) and conventional extracorporeal circulation (Sorin Avant/Maquet Quadrox, CECC), 31 patients in the MECC and 30 patients in the CECC group underwent coronary artery bypass grafting. Endpoints were clinical safety and reduction of transfusion requirements. Cellular metabolism was evaluated by semi-continuous serum lactate measurement during bypass. Together with ECC bypass flows, serum lactate levels were determined every 10min during perfusion.

Results: Mean cardiac index in the CECC group (2.41l/min/m2) was 23% higher than in the MECC group (1.84l/min/m2). In both groups, mean serum lactate during bypass remained low around 1 mmol/dl and was not significantly different. In all patients extracorporeal circulation could be performed without major adverse cardiovascular events like myocardial infarction, stroke and death.

Conclusion: Lower perfusion flows with minimized extracorporeal circulation systems are clinically safe and do not lead to a compromised circulation. Obviously flows below 1, 6l/min/m2 are required during perfusion to cause rising lactate levels.