Affiliations: Department of Surgery, Intensive Care Units, Division of Anaesthesia and Intensive Care Medicine, Helsinki University Hospital, Helsinki, Finland | Critical Care Medicine Research Group, Department of Intensive Care Medicine, Tampere University Hospital, Tampere, Finland | Department of Surgical Sciences, Anaesthesiology and Intensive Care, Uppsala University, Uppsala, Sweden | Institute of Biomedicine, University of Eastern Finland, Anatomy, Kuopio, Finland | University of Helsinki, Helsinki, Finland
Note: [] Corresponding author: Dr. Marko Sallisalmi, Intensive Care Units, Division of Anaesthesia and Intensive Care Medicine, Department of Surgery, Helsinki University Hospital, PB 340 00029 Helsinki, Finland. Tel.: +358 50 3312174; Fax: +358 6 3231448; E-mail: [email protected]
Abstract: BACKGROUND: Total plasma hyaluronan concentration is increased in septic shock. High-molecular-weight hyaluronan has a high intrinsic viscosity. Excessive release of high-molecular-weight hyaluronan in sepsis may induce hyperviscosity. METHODS: Plasma viscosity and the molecular size of plasma hyaluronan were determined in 20 patients with septic shock and in 20 healthy controls. Ex vivo, the effects of 0.4% and 0.047% high-molecular-weight hyaluronan 1560 kDa, 0.9% saline, and 6% hydroxy-ethyl-starch 130 kDa were compared to plasma and whole blood viscosity and red blood cell aggregation at a systemic hematocrit of 0.4, and at a microcirculatory hematocrit of 0.2. RESULTS: Plasma viscosity and total plasma protein content were low in septic shock patients on days one and four of treatment. Hyaluronan concentration was 10-fold higher in sepsis on day 1. Molecular weight of hyaluronan was relatively low, mostly 50–500 kDa, and did not change significantly in sepsis. Ex vivo, 0.4% high-molecular-weight hyaluronan 1560 kDa increased blood viscosity but did not promote red blood cell aggregation. Dilutions of 6% hydroxyl-ethyl-starch 130 kDa and 0.047% high-molecular-weight hyaluronan 1560 kDa had comparable effects on blood viscosity and red blood cell aggregation. CONCLUSIONS: Plasma viscosity of the septic patients remained low for four days despite markedly elevated concentration of relatively small-molecular-weight hyaluronan.
Keywords: High-molecular-weight hyaluronan, viscosity, aggregation, rheology, intensive care
