Hemostatic agents for prehospital hemorrhage control: a narrative review

Hemorrhage is the leading cause of preventable death in combat trauma and the secondary cause of death in civilian trauma.A significant number of deaths due to hemorrhage occur before and in the first hour after hospital arrival.A literature search was performed through PubMed,Scopus,and Institute of Scientific Information databases for English language articles using terms relating to hemostatic agents,prehospital,battlefield or combat dressings,and prehospital hemostatic resuscitation,followed by cross-reference searching.Abstracts were screened to determine relevance and whether appropriate further review of the original articles was warranted.Based on these findings,this paper provides a review of a variety of hemostatic agents ranging from clinically approved products for human use to newly developed concepts with great potential for use in prehospital settings.These hemostatic agents can be administered either systemically or locally to stop bleeding through different mechanisms of action.Comparisons of current hemostatic products and further directions for prehospital hemorrhage control are also discussed.

Effects of Different Culture Conditions and Growth States on the Structure and Hemostatic Properties of Coscinodiscus sp.

As a renewable marine inorganic material,Coscinodiscus sp.has significant potential in the field of rapid hemostasis.However,the low yield of Coscinodiscus sp.seriously limits the application.In this study,two new culture modes were adopted to increase the production of Coscinodiscus sp.,the effect of changes in culture conditions and growth status on the hemostatic activity of diatoms was detected.To prevent Coscinodiscus sp.from sinking in culture,the suspension culture mode was realized by adding0.5%agar.The semi-continuous high nutrient concentration culture mode increased the cell density of Coscinodiscus sp.to 11000cells mL^(-1)and shorten the culture cycle to 5 d.In terms of coagulation activity,the addition of frustules reduced the in vitro coagulation time by half and the activation time of coagulation by 70%.The hemolysis rate and cytotoxicity of frustules harvested in the two culture modes did not change significantly.The results showed that suspension culture mode and high nutrient concentration culture mode only changed the growth state of Coscinodiscus sp.,while the hemostatic performance remained stable.

Accuracy of training blood volume quantifi cation using a visual estimation tool

BACKGROUND:We investigated whether the use of a specially designed visual estimation tool may improve accuracy in quantifying blood volumes related to surface spreading.METHODS:A prospective,paired-control,single-blinded experimental study was performed at a medical university.Anesthesiologists and emergency medical personnel estimated various blood volumes on surfaces with varying absorptivity(carpet,towel,polyvinyl chloride,wooden fl ooring)in an experimental setting.We assessed the sensitivity of training blood volume quantifi cation using a self-designed visual estimation tool by comparing the accuracy of visual blood volume estimations before and after practical training with the tool.RESULTS:A total of 352 estimations by 44 participants were evaluated.Accurate estimations improved significantly from pre-training to post-training(P<0.05).The sensitivity of blood volume quantifi cation was 33.0%after training with the visual estimation tool.Estimations did not depend on age,profession,gender or years of the estimator’s professional experience.CONCLUSIONS:Training with a visual estimation tool by professional rescuers can improve the estimation accuracy of blood volumes spread on surfaces with varying absorptivity.

An improved blood hemorrhaging treatment using diatoms frustules,by alternating Ca and light levels in cultures

Hemorrhage control requires hemostatic materials that are both efective and biocompatible.Among these,diatom biosilica(DBs)could signifcantly improve hemorrhage control,but it induces hemolysis(the hemolysis rate>5%).Thus,the purpose of this study was to explore the infuence of Ca^(2+)biomineralization on DBs for developing fast hemostatic materials with a low hemolysis rate.Here,CaCl_(2)was added to the diatom medium under high light(cool white,fuorescent lamps,67.5µmol m^(−2) s^(−1)),producing Ca-DBs-3 with a particle size of 40-50μm and a Ca^(2+)content of Ca-DBs-3 obtained from the higher concentration CaCl_(2)group(6.7 mmol L^(−1))of 0.16%.The liquid absorption capacity of Ca-DBs-3 was 30.43±0.57 times its dry weight;the in vitro clotting time was comparable to QuikClot®zeolite;the hemostatic time and blood loss using the rat tail amputation model were 36.40±2.52 s and 0.39±0.12 g,which were 40.72%and 19.50%of QuikClot®zeolite,respectively.Ca-DBs-3 showed no apparent toxicity to L929 cells(cell viability>80%)and was non-hemolysis(the hemolysis rate<2%).This study prepared Ca-DBs-3 with a rapid hemostatic efect and good biocompatibility,providing a path to develop diatom biosilica hemostatic materials.