Einfluss von hyperthermen Oberflächen auf Humanblut
- Consequences arising out of elevated surface temperatures on human blood
Schmidt, Verena Isabel; Schmitz-Rode, Thomas (Thesis advisor)
Aachen : Publikationsserver der RWTH Aachen University (2012)
Dissertation / PhD Thesis
Aachen, Techn. Hochsch., Diss., 2012
In order to estimate the impact of exposure of human blood to elevated surface temperatures in blood-conducting systems, detailed data is required. Therefore, titanium alloy housing dummies were immersed in 25 ml heparinized human blood. The dummies were constantly tempered at specific temperatures (37 - 45°C) over 15 minutes as well as one dummy was used as a blank sample and was not tempered. Blood samples were withdrawn for blood parameter analysis and the determination of the plasmatic coagulation cascade. The quantity of adhesions on surfaces were determined by drained weight and underwent histological analysis, likewise one sample was evaluated using FACS (Fluorescent activated Cell Sorter) for further information. With regard to red blood cells, white blood cells, platelets and hematocrit, no statistically significant temperature-dependent difference could be shown at temperatures up to 45°C. Yet, respecting the conditions of the dummies and the blank sample, hemoglobin as well as PF4 (platelet factor 4) seem to be significantly altered by elevated temperatures. Referring to red blood cells, hematocrit, hemoglobin and especially to platelets a significant decrease in terms of cell count could be shown. However, the descent does not appear to be temperature-dependent but correlates with the formation of surface adhesions. Towards 41°C, adhesions seem to increase, whereas temperatures above 43°C show a tendency to a decreasing amount of surface adhesions. Moreover, analyzed by an optical microscope, surface adhesions exposed to higher temperatures demonstrate elevated levels of granulocytes. Also, a temperature-dependent ascending trend towards 43°C could be seen with respect to the amount of activated platelets in FACS analysis.The results of our study suggest that human blood basically tolerates temperatures up to 45°C during the investigated time of 15 minutes. Still, alterations in blood-consistency can be observed. Especially the contact to extrinsic surfaces seems to strongly alter the mentioned parameters. Yet, a critical surface temperature not leading to any undesirable effects on human blood could not be identified within this study.