Effect of dextran-70 on outcome in severe sepsis; a propensity-score matching study

Effects of red blood cell transfusions given to non-septic critically ill patients: a propensity score matched study

INTRODUCTION

Previous studies have demonstrated that low-grade red blood cell transfusions (RBC) given to septic patients are harmful. The objectives of the present study were to compare mortality and morbidity in non-septic critically ill patients who were given low-grade RBC transfusions at haemoglobin level > 70 γ L-1 with patients without RBC-transfusions any of the first 5 days in intensive care.

MATERIAL AND METHODS

Adult patients admitted to a general intensive care unit between 2007 and 2018 at a university hospital were eligible for inclusion. Patients who received > 2 units RBC transfusion per day during the first 5 days after admisasion, with pre-transfusion haemoglobin level < 70 γ L-1 or with severe sepsis or septic shock, were excluded.

RESULTS

In total, 9491 admissions were recorded during the study period. Propensity score matching resulted in 2 well matched groups with 674 unique patients in each. Median pre-transfusion haemoglobin was 98 γ L-1 (interquartile range 91-107 γ L-1). Mortality was higher in the RBC group with an absolute risk increase for death at 180 days of 5.9% (95% CI: 3.6-8.3; P < 0.001). Low-grade RBC-transfusion was also associated with renal, circulatory, and respiratory failure as well as a higher SOFA-max score. Sensitivity analyses suggested that disease trajectories during the exposure time did not significantly differ between the groups.

CONCLUSIONS

Low-grade RBC-transfusions given to non-septic critically ill patients without significant anaemia were associated with increased mortality, increased kidney, circulatory, and respiratory failure, as well as higher SOFA-max score.

Effects of Dextran-70 and Albumin on Coagulation in Experimental Hemorrhage in the Guinea Pig

Background:

Dextran-70 is a more potent plasma volume expander than albumin but use has been hampered because of its antithrombotic properties. However, also albumin has antithrombotic properties and little is known about relative effects of these two colloids on coagulation in vivo when controlling for differences in efficacy as plasma volume expanders.

Aim:

Compare effects of dextran-70 and albumin on coagulation at a dose resulting in equal plasma volume expansion.

Methods:

Guinea pigs were subjected to a 25 mL/kg hemorrhage during 20 min and randomized to resuscitation with either 6% dextran-70 at a dose of 15 mL/kg or 5% albumin at a dose of 25 mL/kg (n = 14 in each group) during 30 min starting 1 h of shock. Blood samples were collected at the completion of resuscitation and at 4 h. Plasma volume was measured using ¹²⁵I-albumin and the effect on coagulation was evaluated using whole blood thrombelastography (TEG), measurement of plasma fibrinogen and von Willebrand factor (vWF) concentrations and vWF glycoprotein 1b (GP1b) A activity.

Results:

Plasma volumes after resuscitation were similar in the groups at both time points. Dextran-70 resulted in a transient prolongation of TEG clot amplification time (K) at the completion of resuscitation compared with albumin. TEG clot initiation (R) and strength (MA) did not differ between the treatments at any of the time points. Albumin reduced vWF concentrations to a larger extent than dextran at both time points, whereas no difference in vWF GP1bA activity or in plasma fibrinogen and could be detected.

Conclusion:

In equipotent doses with regard to plasma volume expansion, dextran-70 transiently prolongs clot amplification time more than albumin whereas dextran-70 reduces plasma vWF concentrations less than albumin.

Comparison of dextran and albumin on blood coagulation in patients undergoing major gynaecological surgery

Background

Hydroxyethyl starches have been withdrawn from the European market. In Sweden, dextran was the main colloid until 2000, when starches overtook the market. After the recent 6S-trial, it was suggested that dextran could be reinstituted, but concerns for greater coagulopathy, bleeding and anaphylaxis still remain. An experimental study from our department indicated that isovolemic substitution of dextran-70 did not derange the von Willebrand function more than albumin 5%, considering the fact that dextran is hyperoncotic in comparison to albumin 5% and, therefore, induces a greater plasma volume expansion and thereby a greater dilutional coagulopathy.

Methods

Eighteen patients undergoing major gynaecological surgery were assigned to receive either 5% albumin or 6% dextran-70 with 9 patients in each group. Standard coagulation tests, including prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and platelet count, viscoelastic coagulation test thromboelastometry (ROTEM) and the Multiplate platelet aggregation test were used to test for coagulation defects at different time points perioperatively. Blood loss, blood loss replacement data and haemodynamic parameters were retrieved from anaesthetic and postoperative charts. A local departmental fluid and transfusion/infusion protocol assured haemoglobin > 90 g/l and mean arterial pressure > 65 mmHg with Ringer’s acetate in addition to the colloid use.

Results

There were no differences in demographic data between the groups. The tissue factor-activated (EXTEM) clot-structure parameter ROTEM A10 was decreased significantly in the dextran group as compared to the albumin group after the infusion of 500 ml of either colloid solution. The PT and aPTT were significantly prolonged, and the platelet count decreased postoperatively in the dextran group, whereas albumin only deranged fibrinogen levels as compared to preoperative levels. There were no differences in Multiplate platelet aggregometry, amount of haemorrhage or transfusion of blood components between the groups.

Conclusions

Standard plasma-based coagulation tests, platelet count and whole blood viscoelastic clot structure are affected by 6% dextran-70 to a greater extent than by 5% albumin, but platelet aggregation is not. Future studies should use more advanced haemodynamic monitoring to assess isovolemic plasma volume expansion with dextran and whether this affects haemostasis to a lesser degree.