A lot of blood is constantly coming back into the operating field during cardiotomy and added to the surgical bleeding. As this is "clean" surgery and the patient is heparinised, all blood is collected in the cardiotomy reservoir through suctions operated with roller pumps like the main pump; their flow rate regulates the strength of the suction. The so-called "left" suction unloads the left heart chambers into which the bronchial circulation continuously pours blood; the cannula is introduced into the aortic root, a pulmonary vein (usually the upper right), the left ventricle or the pulmonary artery. The so-called "right" aspiration draws blood from the surgical field and pleura.
The recovered blood contains air, coagulation and inflammation activators, fat lobules, cell aggregates and various particles that need to be filtered. Aspirations are the main source of haemolysis, protein denaturation, microemboli, platelet loss, coagulation disorders and activation of the inflammatory syndrome [1,5]. For each additional hour of ECC, the embolic burden due to aspiration increases by 90% [2]. To reduce these effects, blood is often drained into an intermediate reservoir where it is temporarily stored and treated with micropore filters and anti-emulsion foams. In the operating field, it is important that the cannulae suck in as little air as possible, and that the suction vacuum is the minimum necessary to keep the site clean. ECC suctions are used as soon as anticoagulation is established (ACT > 400 sec) and until protamine administration begins.
Fluid aspirated into the pericardium contains a very large amount of tissue factor TF, which directly activates factors X and XI of the coagulation cascade, leading to the production of thrombin [4]. Thus the local response triggering the coagulation chain is distributed throughout the body when aspirated blood is poured into the cardiotomy reservoir.
Aspirated blood can be "detoxified" and washed in a centrifugation system such as the CellSaver™. The advantage is that the erythrocytes are concentrated and microaggregates, debris, activated factors (tissue factor, cytokines, free radicals, etc) and electrolytes (potassium) are removed; disruption of the coagulation system is significantly reduced when the aspirated blood is not directly recycled without washing. However, this manoeuvre delays the recirculation of the aspirated blood and unfortunately removes platelets, proteins and coagulation factors, which reduces the benefits of its use, especially in the case of prolonged ECC [6]. Current recommendations favour washing of blood before retransfusion [3].
| Suctions |
| Since surgical field is clean and the patient anticoagulated, blood lost through bleeding can be filtered, washed and stored. Unfortunately, this blood contains many inflammatory triggers and coagulation activators, and washing it (CellSaver™) removes platelets and coagulation factors. |
© CHASSOT PG, GRONCHI F, April 2008, last updateDecember 2019
References
- BROOKER RF, BROWN WR, MOODY DM, et al. Cardiotomy suction: a major source of brain lipid emboli during cardiopulmonary bypass. Ann Thorac Surg 1998; 65:1651-8
- BROWN WR, MOODY DM, CHALLA VR, et al. Longer duration of cardiopulmonary bypass is associated with greater numbers of cerebral microemboli. Stroke 2000; 31:707-13
- KUNST G, MILOJEVIC M, BOER C, et al. 2019 EACTS/EACTA/EBCP guidelines on cardiopulmnary bypass in adult cardiac surgery. Br J Anaesth 2019; 123:713-57
- PHILIPPOU H, ADAMI A, DAVIDSON SJ, et al. Tissue factor is rapidly elevated in plasma collected from the pericardial cavity during CPB. Thromb Haemost 2000; 84:124-8
- SNIECINSKI RM, CHANDLER WL. Activation of the hemostatic system during cardiopulmonary bypass. Anesth Analg 2011; 113:1319-33
- WANG G, BAINBRIDGE D, MARTIN J, et al. The efficacy of an intraoperative cell saver during cardiac surgery: a meta-analysis of randomized trials. Anesth Analg 2009; 109:320-30