Anesth Analg 2008; 106:1588-
© 2008 International Anesthesia Research Society
doi: 10.1213/ane.0b013e31816a31fc
LETTER TO THE EDITOR
Section Editor:
Lawrence Saidman
Which Hemostatic Changes Determine Clinical Outcome?
Sibylle Kozek-Langenecker, MD, and
Gila Scharbert, MD
Department of Anaesthesiology; General Intensive Care and Pain Control; Vienna Medical University; Vienna, Austria; sibylle.kozek{at}meduniwien.ac.at
To the Editor:
Mittermayr et al. assessed the pathomechanisms of dilutional coagulopathy induced by modified gelatin, tetrastarch, or lactated Ringer's solution.1 The experimental protocol consisted of in vivo fluid loading adjusted to the volume effect of the three test solutions. Although the study may have been underpowered for clinical outcome data, transfusions, blood loss, and fibrinogen administration were greatest in patients receiving gelatin. Clot firmness assays, however, were more adversely affected after tetrastarch compared with gelatin and, thus, cannot explain the reported differences in clinical outcome measures. We speculate that thromboelastometric measured (ROTEM) clot firmness (in the presence of tetrastarch) is not an isolated predictor of bleeding and further studies are needed to evaluate the relationship between ROTEM clot polymerization and bleeding in humans. Prothrombin time, fibrinogen concentration (despite substitution), factor VII, and von Willebrand factor decreased more from preoperative baseline in the gelatin group. Are these multifactorial changes pathophysiologically more predictive of bleeding than is functional clot polymerization? Decrease in coagulation factor VII, IX, VIII, and von Willebrand's factor was identified after both colloid infusions and may explain differences in the clinical outcome parameters of blood loss, transfusions, and fibrinogen requirements compared with these in the crystalloid group. Is the role of combined coagulation factor concentrate administration underestimated in our management of massive intraoperative bleeding?
Modified gelatin and tetrastarch had similar negligible effects on platelet function after 20% and 40% in vitro hemodilution.2 Unfortunately, platelet function was not determined in the present study. The sophisticated volume effect-adjusted fluid regimen employed may have permitted detection of colloid-dependent differences in platelet inhibition as another contributing mechanism explaining worse clinical outcome in patients receiving gelatin compared to tetrastarch.
Together, the author's conclusion to prefer gelatin (over tetrastarch) because of higher ROTEM clot firmness values, but without beneficial clinical outcome is not justified.
REFERENCES
- Mittermayr M, Streif W, Haas T, Fries D, Velik-Salchner C, Klingler A, Oswald E, Bach C, Schnapka-Koepf M, Innerhofer P. Hemostatic changes after crystalloid or colloid fluid administration during major orthopedic surgery: The role of fibrinogen administration. Anesth Analg 2007;105:905–17[Abstract/Free Full Text]
- Thaler U, Deusch E, Kozek-Langenecker SA. In vitro effects of gelantin solutions on platelet function: a comparision with hydroxyethyl starch solutions. Anaesthesia 2005;60:554–9[Web of Science][Medline]
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