DRKS00021914.

Study name	Haemodynamic relevance of cardiotomy suction blood for the systemic vascular resistance and requirement of catecholamines
Methods	Participants between 50 and 80 years undergoing primary isolated coronary artery bypass grafting (CABG) under cardiopulmonary bypass (CPB) will be randomised to one of two groups. The method of randomisation is not described. The method of allocation concealment is not described. Study participants and data analysts will be blinded to intervention.
Participants	Participants undergoing primary isolated coronary artery bypass grafting (CABG) under cardiopulmonary bypass (CPB) between ages 50 and 80 years will be randomly allocated to one of two groups. The target sample size is N = 40. Arm 1 (Cardiotomy suction blood) (Control group) Arm 2 (Cell saver blood) (Intervention group) Inclusion criteria Atherosclerotic heart disease 50 to 80 years Isolated CABG with planned more than three grafts Normal haemoglobin level Ejection fraction more than 30% Normal creatinine and glomerular filtration rate (GRF) Exclusion criteria Vasoplegic conditions including sepsis, anaphylactic reactions, haemorrhagic shock, or presence of a peripheral vascular disease Emergency operations, preoperative mechanical circulatory support, combined procedures, or "redos" (revisions). Need for vasoactive substances other than adrenaline, noradrenaline, or dobutamine Need for a transfusion during the intraoperative measurement interval In case of an intraoperative complication with a significant bleeding of more than 1200 mL, the participant will be excluded from the study
Interventions	Arm 1 (Cardiotomy suction blood) (Control): the collected cardiotomy suction blood will be re‐transfused unprocessed Arm 2 (Cell saver blood) (Intervention): the collected cardiotomy suction blood will be processed by a cell saver prior to re‐transfusion
Outcomes	Systemic vascular resistance, consumption of sympathomimetics, renal function, blood loss
Starting date	Date of first enrolment: 01 June 2020
Contact information	Mr. Dr. med. Aschraf El‐Essawi: aschraf.el‐essawi at med.uni‐goettingen.de
Notes	Transfusion protocol: a transfusion protocol is not reported Prospective registration status: trial has been prospectively registered on the German Clinical Trials Register (DRKS) (Date of registration 04 June 2020) Ethical approval: study has been approved by an ethics Committee Nr.: 30/09/18, Ethik‐Kommission der Medizinischen Fakultät der Georg‐August‐Universität Göttingen Language: information available in the DRKS is available in German and English