[Contribution of hemostatic dressings in the hemostasis of arteriovenous fistula? A quality improvement program in our center]

INTRODUCTION

In haemodialysis patients the length of bleeding times after fistula cannulation is an easy and fairly used method of monitoring vascular access. In the most cases, compression is performed manually by nurses and the use of haemostatic dressing is common. As data in the literature are scares, we have decided to develop a quality improvement program in our hemodialysis center to manage this issue.

MATERIAL AND METHODS

After informed consent, 35 hemodialysis outpatients were selected in order to study the bleeding time using haemostatic dressing or not during two weeks in a cross over schema. The dialysis schedule was unchanged and comparative analysis of parameters such as blood flow rate or anticoagulant treatment were done between the groups.

RESULTS

Compression times with and without hemostatic dressing were not different (12.6 min and 12.9 min, respectively). Patients with an anticoagulation during the dialysis session greater than 0.35 IU/kg/session had a longer bleeding time (12.75 min vs 11.75 min; P=0.008).

CONCLUSION

In our evaluation, the use of haemostatic dressings is not associated with a real shorter bleeding time. Their use generate an additional cost estimated on average at 164 euros/year/patient. Patients and team realized that compression time is important for fistula monitoring and using compresses does not really increase this time.

Hemostatic shape memory polymer foams with improved survival in a lethal traumatic hemorrhage model

Although there are many hemostatic agents available for use on the battlefield, uncontrolled hemorrhage is still the primary cause of preventable death. Current hemostatic dressings include QuikClot® Combat Gauze (QCCG) and XStat®, which have inadequate success in reducing mortality. To address this need, a new hemostatic material was developed using shape memory polymer (SMP) foams, which demonstrate biocompatibility, rapid clotting, and shape recovery to fill the wound site. SMP foam hemostatic efficacy was examined in a lethal, noncompressible porcine liver injury model over 6 h following injury. Wounds were packed with SMP foams, XStat, or QCCG and compared in terms of time to bleeding cessation, total blood loss, and animal survival. The hemostatic material properties and in vitro blood interactions were also characterized. SMP foams decreased blood loss and active bleeding time in comparison with XStat and QCCG. Most importantly, SMP foams increased the 6 h survival rate by 50% and 37% (vs. XStat and QCCG, respectively) with significant increases in survival times. Based upon in vitro characterizations, this result is attributed to the low stiffness and shape filling capabilities of SMP foams. This study demonstrates that SMP foams have promise for improving upon current clinically available hemostatic dressings and that hemostatic material properties are important to consider in designing devices for noncompressible bleeding control. STATEMENT OF SIGNIFICANCE: Uncontrolled hemorrhage is the leading cause of preventable death on the battlefield, and it accounts for approximately 1.5 million deaths each year. New biomaterials are required for improved hemorrhage control, particularly in noncompressible wounds in the torso. Here, we compared shape memory polymer (SMP) foams with two clinical dressings, QuikClot Combat Gauze and XStat, in a pig model of lethal liver injury. SMP foam treatment reduced bleeding times and blood loss and significantly improved animal survival. After further material characterization, we determined that the improved outcomes with SMP foams are likely due to their low stiffness and controlled shape change after implantation, which enabled their delivery to the liver injuries without inducing further wound tearing. Overall, SMP foams provide a promising option for hemorrhage control.

Hemostatic dressings based on poly(vinyl formal) sponges

The development of novel hemostatic agents is related to the fact that severe blood loss due to hemorrhage continues to be the leading cause of preventable death of patients with military trauma and the second leading cause of death of civilian patients with injuries. Herein we assessed the hemostatic properties of porous sponges based on biocompatible hydrophilic polymer, poly(vinyl formal) (PVF), which meets the main requirements for the development of hemostatic materials. A series of composite hemostatic materials based on PVF sponges with different porosities and fillers were synthesized by acetalization of poly(vinyl alcohol) with formaldehyde. Nano-sized aminopropyl silica, micro-sized calcium carbonate, and chitosan hydrogel were used to modify PVF matrixes. The physicochemical properties (pore size, elemental composition, functional groups, hydrophilicity, and acetalization degree) of the synthesized composite sponges were studied by gravimetrical analysis, optical microscopy, scanning electron microscopy combined with energy dispersive x-ray spectroscopy, infrared spectroscopy, and nuclear magnetic resonance. Hemostatic properties of the materials were assessed using a model of parenchymal bleeding from the liver of white male Wistar rat with a gauze bandage as a control. All investigated PVF-based porous sponges showed high hemostatic activity: upon the application of PVF-samples the bleeding decreased within 3 min by 68.4-94.4% (р < 0.001). The bleeding time upon the application of PVF-based composites decreased by 78.3-90.4% (p < 0.001) compared to the application of well-known commercial product Celox™.

Comprehensive assessment of Nile tilapia skin collagen sponges as hemostatic dressings

Nile tilapia skin collagen sponge was fabricated by lyophilization and cross-linked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide in the presence of N-hydroxysuccinimide (EDC/NHS). The physicochemical properties were examined. The EDC/NHS cross-linked collagen sponge presented an enhanced water absorption capacity. In addition, biocompatibility and hemostatic efficiency were evaluated by acute systemic toxicity assay, dermal irritation test, intradermal reaction test, sensitization test, cytotoxicity, blood clotting assay in vitro, and liver and femoral artery hemorrhage models in vivo. Results showed that the produced collagen sponges before and after EDC/NHS cross-linking had excellent biocompatibility. Furthermore, EDC/NHS cross-linking promoted fibroblast cells viability and proliferation reflected by the MTT reduction assay. Meanwhile, EDC/NHS cross-linked collagen sponge exhibited the best blood clotting ability and hemostatic efficiency in rat femoral artery hemorrhage model in comparison with non-crosslinked and commercial collagen sponges. Our results demonstrated that the fabricated collagen sponges could be used as perfect hemostatic dressings.

Penetrating Vascular Injury: Diagnosis and Management Updates

Penetrating vascular injury is becoming increasingly common in the United States and abroad. Much of the current research and treatment is derived from wartime and translation to the civilian sector has been lacking. Penetrating vascular injury can be classified as extremity, junctional, or noncompressible. Diagnosis can be obvious but at other times subtle and difficult to diagnose. Although there are numerous modalities, computed tomography angiography is the diagnostic study of choice. It is hoped that care will be improved by using an algorithmic approach integrating experience from military and civilian research.

The effect of hemostatic dressing prototypes for the uniformed services on selected blood coagulation parameters in pigs

Background

Serious injuries accompanied by severe bleeding are life-threatening. Post-traumatic hemorrhage involves the risk of developing coagulopathy. Hemostatic dressings are widely used to minimize bleeding. The application of procoagulants in control of hemorrhage may lead to thrombosis or disseminated intravascular coagulation. The aim of this study was to evaluate the effect of hemostatic dressing prototypes on the porcine coagulation system.

Results

Fibrinogen and d-dimer concentrations were significantly higher in the experimental groups where hemostatic dressings were used in comparison with the control group. Considerable differences in antithrombin III activity and thrombin–antithrombin complex concentrations were also observed between groups.

Conclusions

The hemostatic dressing comprising modified seton impregnated with 18.0 g/m² of procoagulant was most effective in preserving the physiological equilibrium between fibrinogenesis and fibrinolysis.