Transfusion therapy after cardiac surgery is empirically guided, partly due to a lack of specific point-of-care hemostasis monitors. In a randomized, blinded, prospective trial, we studied cardiac surgical patients at moderate to high risk of transfusion. Patients were randomly assigned to either a thromboelastography (TEG)-guided transfusion algorithm (n 5 53) or routine transfusion therapy (n 5 52) for intervention after cardiopulmonary bypass. Coagulation tests, TEG variables, mediastinal tube drainage, and transfusions were compared at multiple time points. There were no demographic or hemostatic test result differences between groups, and all patients were given prophylactic antifibrinolytic therapy. Intraoperative transfusion rates did not differ, but there were significantly fewer postoperative and total transfusions in the TEG group. The proportion of patients receiving freshfrozen plasma (FFP) was 4 of 53 in the TEG group compared with 16 of 52 in the control group (P , 0.002). Patients receiving platelets were 7 of 53 in the TEG group compared with 15 of 52 in the control group (P , 0.05). Patients in the TEG group also received less volume of FFP (36 6 142 vs 217 6 463 mL; P , 0.04). Mediastinal tube drainage was not statistically different 6, 12, or 24 h postoperatively. Point-of-care coagulation monitoring using TEG resulted in fewer transfusions in the postoperative period. We conclude that the reduction in transfusions may have been due to improved hemostasis in these patients who had earlier and specific identification of the hemostasis abnormality and thus received more appropriate intraoperative transfusion therapy. These data support the use of TEG in an algorithm to guide transfusion therapy in complex cardiac surgery. Implications: Transfusion of allogeneic blood products is common during complex cardiac surgical procedures. In a prospective, randomized trial, we compared a transfusion algorithm using point-of-care coagulation testing with routine laboratory testing, and found the algorithm to be effective in reducing transfusion requirements. (Anesth Analg 1999;88:312‐9)

Thromboelastography-guided transfusion algorithm reduces transfusions in complex cardiac surgery.

Platelet transfusions during coronary artery bypass graft surgery are associated with serious adverse outcomes

ObjectiveTo compare the effects of different colloid plasma substitutes on blood coagulation and postoperative blood loss.Data SourcesRelevant studies were obtained from the medical literature.Study Selection Articles were selected that provided data on the effects of colloids on hemostasis and post

Effects of different plasma substitutes on blood coagulation: a comparative review.

HYDROXYETHYL starch (HES) solutions are frequentlyused plasma expanders that are indicated to restore andmaintain intravascular volume, to stabilize hemodynamicconditions, and to improve tissue perfusion. Accordingto these clinical indications, HES is used in perioperativesituationswithahighriskofbleeding.SideeffectsofHESon hemostasis pose serious limitations to the clinical useof this artiﬁcial colloid. Recent developments have cen-tered around designing new starch molecules by modu-lating their pharmacochemical characteristics to in-crease colloid osmotic pressure and hemodynamicefﬁcacy while minimizing the risk of adverse reactionssuch as antithrombotic effects. The aim of this ClinicalConcepts and Commentary article is to provide clini-cians with a brief overview of the literature on potentialside effects of various HES preparations, includinghetastarches, pentastarches, and the novel tetrastarches,on both plasmatic and cellular hemostasis.

Effects of Hydroxyethyl Starch Solutions on Hemostasis

Albumin versus hydroxyethyl starch in cardiopulmonary bypass surgery: a meta-analysis of postoperative bleeding.

Hydroxyethyl starch (HES) is efficacious as a volume expander in cardiac surgical patients, but it may impair the haemostatic mechanisms. However, this latter effect may be less conspicuous with low molecular weight (LMW) solutions than with high molecular weight (HMW) solutions. Therefore, LMW– and HMW–HES solutions were evaluated as priming solutions for cardiopulmonary bypass (CPB) with respect to their effect on haemostasis. Forty–five patients undergoing coronary bypass grafting were prospectively randomised to three groups and in a double–blind manner as their CPB prime either 20 ml kg-1 LMW–HES (Mw 120 000), 20 ml kg-1 HMW–HES (Mw 400000) or Ringer's acetate 2000 ml. The final volume of the prime was completed to 2000 ml with Ringer's acetate in the HES groups. Anaesthesia and CPB management were standardised. Plasma levels of von Willebrand factor antigen and factor VIII procoagulant activity were significantly more depressed after CPB in both HES–groups as compared with the crystalloid prime group. In addition, APTT was more prolonged and the maximal amplitude of thromboelastographic tracing was more decreased in the HES–groups. It is concluded that it may be advisable to avoid HES solutions in the CPB prime, especially in patients with an increased risk for bleeding after cardiac operations.

Hydroxyethyl starch as a prime for cardiopulmonary bypass: effects of two different solutions on haemostasis

Background: Since the discovery of HIV, minimizing the use of donor blood has become increasingly important in surgical activity. In Finland, however, the use of homologous red blood has grown considerably during the past years. Therefore, we found it necessary to conduct a nationwide survey of transfusion practices in elective surgery. This report deals with transfusions in coronary artery bypass (CABG) operations in all Finnish cardiac centres.



Methods: The study group comprised 804 primary CABG patients operated during a 2-year period. Two reviewers retrospectively examined the data concerning the use of and indications for homologous and autologous blood in the patient charts.



Results: In all, 705 (88%) of patients received homologous blood. The proportions of patients receiving blood components differed between hospitals: from 53 to 99% for red cells, 2 to 22% for fresh frozen plasma and 5 to 49% for platelets. The variation was not caused by diverse patient populations: the mean number of blood component units transfused per patient differed from 1 to 6 between centres — even after adjustment for confounding variables. Multiple blood conservation methods were used in one centre. Nevertheless, homologous blood was administered to 88% of their patients.



Conclusions: A considerable proportion of CABG patients are transfused with homologous blood in Finland compared to other countries. In addition, the transfusion practices proved highly variable between hospitals and were determined largely by local opinions. This study reveals a clear demand for prospective studies and constructive discussion among anaesthesiologists to establish uniform guidelines for blood use in cardiac surgery.

Transfusion policies in coronary artery bypass — a nationwide survey in Finland

The safety of plasma expanders, hydroxyethyl starch 120 and dextran 70, administered in the highest recommended doses (20 ml/kg) as adjuncts of component therapy of surgical blood loss was studied in patients undergoing major abdominal surgery and compared with a group receiving 4% albumin solution for initial haemodilution and whole blood for further blood loss replacement. Each group consisted of five patients in a relatively severe surgical, but good general condition including a normal haemostatic function and serum albumin level. The dilutional effect of the expanders on serum albumin and prothrombin-proconvertin level was observed during the day of operation. On the first postoperative day these values were equally low in all groups. Platelet count and bleeding time remained on a safe level throughout the study in all groups. Partial thromboplastic time values were unchanged. The factor VIII procoagulant (C), related antigen (R:Ag, vWF:Ag) and ristocetin cofactor levels, which were high preoperatively due to the underlying disease, remained at a safe level throughout the study. The increase in factor VIII related antigen associated with the hypercoagulable state induced by the surgical trauma was prevented by the plasma expanders. We conclude that dextran and hydroxyethyl starch can be used safely in a dose of 20 ml/kg in component therapy of surgical blood loss, provided that haematocrit is kept at an acceptable level, attention is paid to the postoperative hypoproteinaemia, and the patient has a normal haemostatic function preoperatively.

G. Myllylä

Papers

Hydroxyethyl starch as a prime for cardiopulmonary bypass: effects of two different solutions on haemostasis

Transfusion policies in coronary artery bypass — a nationwide survey in Finland

A study of haemostasis following the use of high doses of hydroxyethyl starch 120 and dextran in major laparotomies.