HYDROXYETHYL STARCH AS A PRIME FOR CARDIOPULMONARY BYPASS - EFFECTS OF 2 DIFFERENT SOLUTIONS ON HEMOSTASIS

Hydroxyethyl starch (HES) is efficacious as a volume expander in cardi ac surgical patients, but it may impair the haemostatic mechanisms. Ho wever, this latter effect may be less conspicuous with low molecular w eight (LMW) solutions than with high molecular weight (HMW) solutions. Therefore, LMW- and HMW-HES solutions were evaluated as priming solut ions for cardiopulmonary bypass (CPB) with respect to their effect on haemostasis. Forty-five patients undergoing coronary bypass grafting w ere prospectively randomised to three groups and received in a double- blind manner as their CPB prime either 20 ml . kg-1 LMW-HES (M(w) 1200 00), 20 ml . kg-1 HMW-HES (M(w) 400000) or Ringer's acetate 2000 ml. T he final volume of the prime was completed to 2000 ml with Ringer's ac etate in the HES groups. Anaesthesia and CPB management were standardi sed. Plasma levels of von Willebrand factor antigen and factor VIII pr ocoagulant activity were significantly more depressed after CPB in bot h HES-groups as compared with the crystalloid prime group. In addition , APTT was more prolonged and the maximal amplitude of thromboelastogr aphic tracing was more decreased in the HES-groups. It is concluded th at it may be advisable to avoid HES solutions in the CPB prime, especi ally in patients with an increased risk for bleeding after cardiac ope rations.