Objective To investigate the clinical use of blood in Shenzhen,in order to make the blood transfusion more appropriate and safer.Methods The medical records of 2 597 blood transfusion receipts from 3 hospitals in 2006 were reviewed.The use of blood components in each department,unreasonable prescriptions of very small amount of blood transfusion,and the combined transfusion of RBC and plasma were analyzed.Results The proportion of reasonable transfusion of RBC,plasma,platelet concentrates and cryoprecipitate were 66.44%,24.65%,97.97% and 61.29%,respectively.These proportion were 91.54%,51.85%,98.86%,and 100%,respectively,in internal medicine department,and 50.22%,19.86%,89.58%,42.86%,respectively,in surgery department.Unreasonable prescription of low-volume blood transfusion and the combined transfusion of RBC and plasma were 47.05% and 51.17%.Conclusion Except for plasma transfusion,the internal medicine departments did fairly well in blood component transfusion.Since the unreasonable transfusion still exists,the clinical doctors should be further trained in the appropriate use of blood,and get rid of the old practice of whole-blood-dependence.

Objective To quantitatively explore the influence of knife sharpness on forearm wounds in knife slash cases. Methods The finite element models of the upper limb and knives with 3 degrees of sharpness (with sharp blade, blunt blade, wide blade) were developed based on human CT images and prototype of slash knife. The slash by 3 kinds of knives on the forearm at velocity of 4 m/s and duration of 10 ms was simulated, so as to analyze changes in contact forces, wound dimensions and energy. Results During the slash by knives with sharp, blunt, wide blade, the blades reached the ulna at about 65, 85, 95 ms, respectively. The corresponding slash forces were 846, 1 064 and 1 865 N; the wound lengths were 135.64, 105.47 and 99.23 mm; the wound depths were 38.77, 27.81 and 18.74 mm. With the sharpness of blade decreasing, the wound formation was slowed, the length and depth decreased and the slash force increased. The model system for slash knife with sharp blade had obviously greater total energy and inner energy, but smaller kinetic energy, compared with slash knife with blunt blade and wide blade. Conclusions The method for quantitatively assessing wound formation in knife slash upon the forearm was developed. The research findings deepen the understanding of biomechanical mechanism of wound formation by knife slash, and provide new scientific means for forensic investigation and court trial of knife slash cases.