The effects of intentional hyperthermia on the Thrombelastograph and the Sonoclot analyser

Abstract

The effect of whole-body hyperthermia (WBH) on viscoelastic properties of whole blood, as measured by the thrombelastogram (TEG) and Sonoclot analyser, was investigated in 10 patients undergoing WBH-carboplastin therapy for metastatic disease. Blood was taken from an existing central line at baseline (37oC), during warming (39 and 41oC) and cooling (39 and 37oC). Sonoclot and TEG samples were analysed simultaneously at 37oC and at the patient's temperature with a temperature-compensated unit, except at 41oC for the Sonoclot (maximum temperature adjustment of 40oC). TEG measurements included R time (time to initial fibrin formation [mm]), K time (mm) and alpha angle (degrees) (both reflecting fibrinogen-platelet interaction), maximum amplitude (representing qualitative platelet function [mm]) and per cent fibrinolysis at 30 and 60min. The Sonoclot ACT (SonACT-secs), initial rate of clot formation (% ), time to peak amplitude (min) and peak amplitude of the Sonoclot signature (mm) were recorded. Decreased R time of the TEG compared to a marginally elevated baseline was found at all times during warming and cooling (p < 0.05). The K time was decreased at 41oC compared to a normal baseline (p < 0.05). The SonACT was decreased (from an elevated baseline) at all other times, without differences in measures at patient temperature versus 37oC (p < 0.05). The data suggest acceleration of fibrin formation during WBH to 41oC in patients with malignancy. Implications for defining thromboembolic risk require further investigation.

• Coagulation;Thrombelastography;Sonoclot Analyser;Hyperthermia;Whole-body Cancer