BACKGROUND: Dysfunctional inflammation following traumatic hemorrhage can lead to multiple-organ failure and death. In our polytrauma swine model, lyophilized plasma (LP) reconstituted with sterile water and ascorbic acid suppressed systemic inflammation and attenuated DNA damage. However, it remains unknown whether the inflammatory response is affected by the type of fluid used to reconstitute LP. We hypothesized that common resuscitation fluids such as normal saline (LP-NS), lactated Ringer's solution (LP-LR), Hextend (LP-HX), or sterile water (LP-SW) would yield similar inflammation profiles and DNA damage following LP reconstitution and transfusion. METHODS: This was a randomized, prospective, blinded animal study. LP was reconstituted to 50% of original volume with NS, LR, HX, or SW buffered with 15-mM ascorbic acid. Forty swine were subjected to a validated model of polytrauma, hemorrhagic shock, and Grade V liver injury and resuscitated with LP. Serum interleukin 6 (IL-6), IL-10, plasma C-reactive protein, and 8-hydroxy-2-deoxyguanosine concentrations were assessed for systemic inflammation and DNA damage at baseline, 2 hours, and 4 hours following liver injury. Lung inflammation was evaluated by Real Time Polymerize Chain Reaction (RT-PCR). RESULTS: Reconstituted LP pH was similar between groups before resuscitation. IL-6 and IL-10 increased at 2 hours and 4 hours compared with baseline in all groups (p < 0.017). DNA damage increased at 2 hours and 4 hours compared with baseline and from 2 hours to 4 hours in the LP-NS, LP-LR, and LP-SW groups (all p < 0.017). Animals resuscitated with LP-HX not only demonstrated increased DNA damage at 4 hours versus baseline but also had the lowest C-reactive protein level at 2 hours and 4-hours (p < 0.017). Overall, differences between groups were similar for DNA damage and lung inflammation. CONCLUSION: Reconstitution fluid type does not affect inflammatory cytokine profiles or DNA damage following LP transfusion in this swine polytrauma model. Based on universal availability, these data suggest that sterile water is the most logical choice for LP reconstitution in humans. (Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.)

BACKGROUND Low-volume ascorbic acid–buffered reconstituted lyophilized plasma (LP) provides logistic advantages, reduces the risks for large-volume resuscitation, modulates inflammation, and is equally effective for hemostatic resuscitation as full-volume LP. We compared the physiologic effects of resuscitation using LP reconstituted with sterile water (LP-SW), lactated Ringer’s solution (LP-LR), normal saline (LP-NS), and Hextend (LP-Hx). METHODS Plasma was collected from swine, lyophilized, and then reconstituted into four test solutions: LP-SW, LP-LR, LP-NS, or LP-Hx. Forty swine were anesthetized and subjected to a validated model of polytrauma and hemorrhagic shock (including a Grade V liver injury), then randomized to receive one of the four test solutions. Physiologic parameters, blood loss, lactate, and hematocrit were followed up. Coagulation status was evaluated using thrombelastography. Inflammatory mediator expression was evaluated by multiplex serum assay. RESULTS Forty animals were included in the study (10 animals per group). One animal died following LP-Hx resuscitation. There was less blood loss in the LP-SW and LP-LR groups compared with the LP-NS and LP-Hx groups (p < 0.05). The LP-SW group exhibited less early coagulopathic changes by thrombelastography, and the LP-Hx group had persistently elevated international normalized ratios at the end of the study period (p < 0.05). Serum interleukin 6 was lower after 4 hours in the LP-SW group compared with LP-NS (p < 0.05). CONCLUSION Resuscitation using low-volume LP-SW and LP-LR buffered with ascorbic acid confers an anti-inflammatory benefit and results in less blood loss. Sterile water is a safe, cost-effective, and universally available fluid for creating a low-volume hemostatic LP resuscitation solution.

IMPORTANCE Enoxaparin sodium is widely used for deep vein thrombosis (DVT) prophylaxis, yet DVT rates remain high in the trauma and general surgery populations. Missed doses during hospitalization are common. OBJECTIVE To determine if missed doses of enoxaparin correlate with DVT formation. DESIGN, SETTING, AND PARTICIPANTS Data were prospectively collected among 202 trauma and general surgery patients admitted to a level I trauma center. MAIN OUTCOMES AND MEASURES Deep vein thrombosis screening was performed using a rigorous standardized protocol. RESULTS The overall incidence of DVT was 15.8%. In total, 58.9% of patients missed at least 1 dose of enoxaparin. The DVTs occurred in 23.5% of patients who missed at least 1 dose and in 4.8% of patients who did not (P < .01). On univariate analysis, the need for mechanical ventilation (71.8% vs 44.1%), the performance of more than 1 operation (59.3% vs 40.0%), and male sex (75% vs 56%) were associated with DVT formation (P < .05 for all). A bivariate logistic regression was then performed, which revealed age 50 years or older and interrupted enoxaparin therapy as the only independent risk factors for DVT formation. The DVT rate did not differ between trauma and general surgery populations or in patients receiving once-daily vs twice-daily dosing regimens. CONCLUSIONS AND RELEVANCE Interrupted enoxaparin therapy and age 50 years or older are associated with DVT formation among trauma and general surgery patients. Missed doses occur commonly and are the only identified risk factor for DVT that can be ameliorated by physicians. Efforts to minimize interrupted enoxaparin prophylaxis in patients at risk for DVT should be optimized.

BACKGROUND:The International Normalized Ratio (INR) is commonly used to guide therapy after hepatectomy. We hypothesized that the use of thrombelastography (TEG) would demonstrate a decreased incidence of hypocoagulability in this patient population. METHODS:Seventy-eight patients were prospectively enrolled before undergoing hepatectomy. INR, TEG, and coagulation factors were drawn before incision, postoperatively, and on postoperative days 1, 3, and 5. RESULTS:Patients demonstrated an elevated INR at all postoperative time points. However, TEG demonstrated a decreased R value postoperatively, with subsequent normalization. Other TEG measurements were equivalent to preoperative values. All procoagulant factors save factor VIII decreased postoperatively, with a simultaneous decrease in protein C. CONCLUSIONS:TEG demonstrated a brief hypercoagulable state after major hepatectomy, with coagulation subsequently normalizing. The INR significantly overestimates hypocoagulability after hepatectomy and these data call into question current practices using the INR to guide therapy in this patient population.

BACKGROUND The international normalized ratio (INR) was developed to assess adequacy of Coumadin dosing. Its use has been generalized to guide fresh frozen plasma (FFP) therapy in stable patients. Thrombelastography (TEG) is a whole-blood assay measuring the viscoelastic properties of the clot in near real time. This study hypothesized that INR does not reflect coagulopathy and should not be used to guide FFP therapy in stable trauma and surgical patients. METHODS Prospective observational data were collected from stable trauma and surgical patients (n = 106) who received FFP transfusions. Pretransfusion and posttransfusion blood samples were obtained to assess complete blood count, standard coagulation parameters (INR, partial thromboplastin time, fibrinogen and D-dimer), soluble clotting factors (II, V, VII, VIII, IX, X, XI, XII, proteins C and S) and TEG. Data were analyzed using a Mann-Whitney U-test. Significance was defined as p < 0.05. RESULTS A total of 262 U of FFP were transfused, with 78% of 106 patients receiving two or more units. Despite a reduction in INR, median TEG values remained within normal limits, while clotting factor levels retained adequate function to produce normal clotting before and following FFP transfusion. CONCLUSION The use of FFP in this population did not affect coagulation status in a clinically relevant manner based on TEG values and coagulation factor function. INR is not a predictor of coagulopathy and should not be used to guide coagulation factor replacement in stable trauma and surgical patients. LEVEL OF EVIDENCE Diagnostic study, level III.

BACKGROUND:The purpose of this study was to compare standard gauze (SG) and advanced hemostatic dressings in use by military personnel in a no-hold model. METHODS:A randomized, controlled trial was conducted using 36 swine. Animals underwent femoral arteriotomy, followed by 60 seconds of uncontrolled hemorrhage. After hemorrhage, packing with 1 of 3 dressings-SG, Combat Gauze (CG), or Celox Rapid gauze (XG)-and a 500-mL bolus of Hextend were initiated. Pressure was not held after packing, and animals were followed for 120 minutes. Physiologic parameters were monitored continuously, and electrolyte and hematologic laboratory assessments were performed before injury and 30 and 120 minutes after injury. Dressing failure was determined if bleeding occurred outside the wound. RESULTS:All animals survived to study end. Baseline characteristics were similar between groups. No statistical difference was seen in initial blood loss or dressing success rate (SG, 10 of 12; CG, 10 of 12; and XG, 12 of 12). Secondary blood loss was significantly less with XG (median, 12.8 mL; interquartile range, 8.8 to 39.7 mL) compared with SG (median, 44.7 mL; interquartile range, 17.8 to 85.3 mL; P = .02) and CG (median, 31.9 mL; interquartile range, 18.6 to 69.1 mL; P = .05). Packing time was significantly shorter with XG (mean, 37.1 ± 6.2 seconds) compared with SG (mean, 45.2 ± 6.0 seconds; P < .01) and CG (mean, 43.5 ± 5.6 seconds; P = .01). CONCLUSIONS:XG demonstrated shorter application time and decreased secondary blood loss in comparison with both SG and CG. These differences may be of potential benefit in a care-under-fire scenario.

BACKGROUND:Shock and severe tissue injury lead to an endogenous coagulopathy mediated by activation of Protein C and hyperfibrinolysis known as acute traumatic coagulopathy. Together, hemodilution, acidosis, inflammation, and hypothermia result in a global trauma-induced coagulopathy. Coagulopathy in trauma is associated with mortality. Early and effective hemostatic resuscitation is critical in restoring perfusion, correcting coagulopathy, and saving lives in exsanguinating trauma. Lyophilized plasma (LP) provides a logistically superior alternative to fresh frozen plasma (FFP).STUDY DESIGN AND METHODS:Plasma was lyophilized following whole blood collection from anesthetized swine. A series of studies were performed using anesthetized swine subjected to a validated model of polytrauma and hemorrhagic shock including a Grade V liver injury. Animals were randomized to resuscitation using reconstituted LP fluids. Physiologic data and blood loss were measured. Coagulation status and inflammatory mediators were evaluated.RESULTS:Full volume reconstituted LP (100%LP) retains on average 86% coagulation factor activity compared to fresh plasma and when used in 1:1 ratios with red blood cells demonstrated superior hemostatic efficacy compared to FFP. Hypertonic LP reconstituted using 50% of the original plasma volume (50%LP) had higher coagulation factor concentrations, was well tolerated in swine, and equally effective compared to 100%LP with respect to physiologic and hemostatic properties. Buffering with ascorbic acid resulted in significant reductions in serum levels of tumor necrosis factor alpha and interleukin-6.CONCLUSION:By minimizing the volume of reconstituted LP and optimizing its anti-inflammatory properties, an LP resuscitation fluid may be created to provide effective hemostatic resuscitation with superior logistical properties.

BACKGROUND:During preservation, donated liquid red blood cells (RBCs) experience multiple functional and structural changes known as the storage lesion. Increased RBC age is associated with increased infection rates, organ failure, and mortality.METHODS:This prospective, randomized, double-blinded pilot study enrolled stable trauma patients who required RBC transfusion. Patients were randomly assigned to receive standard or cryopreserved RBCs. Continuous tissue oxygenation (StO2) monitoring was performed during the peritransfusion period. Hematocrit and thrombelastography before and after transfusion were evaluated. Patients were monitored for transfusion reactions and clinical outcomes.RESULTS:Fifty-seven patients were randomized, and groups were well matched for demographics and Injury Severity Score (ISS). No statistically significant differences were noted in hematocrit change, thrombelastography parameters, transfusion reactions, or clinical outcomes. StO2 was found to be higher in the cryopreserved group.CONCLUSION:Cryopreserved RBCs are equally safe and efficacious to refrigerated RBCs. This storage technique extends the life span of RBCs to 10 years, potentially preserving a precious resource and preventing the storage lesion. StO2 was superior in patients receiving cryopreserved RBCs. This finding has the potential to drive a paradigm shift in transfusion practices.LEVEL OF EVIDENCE:Therapeutic study, level II.

BACKGROUND:Previous studies have shown large-volume resuscitation modulates coagulopathy and inflammation. Our objective was to analyze the effects of initial bolus fluids used in military and civilian settings on coagulation and inflammation in a prospective, randomized, blinded trial of resuscitation of uncontrolled hemorrhage.METHODS:Fifty swine were anesthetized, intubated, and ventilated and had monitoring lines placed. A Grade V liver injury was performed followed by 30 minutes of hemorrhage. After 30 minutes, the liver was packed, and randomized fluid resuscitation was initiated during a 12-minute period with 2 L of normal saline, 2 L of lactated Ringer's solution, 250 mL of 7.5% saline with 3% Dextran, 500 mL of Hextend, or no fluid (NF). Animals were monitored for 2 hours after injury. Thrombelastograms (TEGs), prothrombin time (PT), partial thromboplastin time, fibrinogen as well as serum interleukin 6, interleukin 8, and tumor necrosis factor α levels were drawn at baseline and after 1 hour and 2 hours.RESULTS:The NF group had less posttreatment blood loss compared with other groups (p < 0.01). Blood loss was similar in the other groups. TEG R values in each group decreased from baseline at 1 and 2 hours (p < 0.02). The groups receiving 2 L of normal saline, 250 mL of 7.5% saline with 3% Dextran, or 500 mL of Hextend had lower TEG maximum amplitude values compared with NF group (p < 0.02). All fluids except lactated Ringer's solution resulted in significant increases in PT compared with NF, whereas all fluids resulted in significant decreases in fibrinogen compared with NF (p < 0.02). Fluid resuscitation groups as well as NF group demonstrated significant increases in inflammatory cytokines from baseline to 1 hour and baseline to 2 hours. There were no significant differences in inflammatory cytokines between groups at 2 hours.CONCLUSION:Withholding fluid resulted in the least significant change in PT, fibrinogen, and maximum amplitude and in the lowest posttreatment blood loss. Resuscitation with different initial fluid resuscitation strategies did not result in increased proinflammatory mediators compared with animals that did not receive fluid.

BACKGROUND:Prothrombin time-international normalized ratio (PT-INR) is widely utilized to guide plasma therapy and initiation of thromboprophylaxis after a hepatectomy. Thrombelastography (TEG) monitors shear elasticity, which is sensitive to cellular and plasma components in blood, allowing for functional assessment of the life of the clot. The objective of this study was to prospectively compare PT-INR and TEG in liver resection patients.METHODS:Forty patients were enrolled before undergoing an elective hepatectomy. Patients underwent a liver resection utilizing a low central venous pressure (CVP) anaesthetic technique and intermittent Pringle manoeuver. PT-INR and TEG were drawn prior to incision, post-operatively, and post-operative days 1, 3 and 5.RESULTS:All post-operative PT-INR values increased significantly when compared with pre-operative PT-INR (P < 0.01). The time of onset to clot (R-value) decreased significantly at the post-operative time point (P = 0.04), consistent with a relative hypercoagulability. Subsequent R-values were not different compared with the pre-operative R-value. The strength of the clot (maximum amplitude, MA) was unchanged when comparing pre- and post-operative time points.DISCUSSION:In spite of an elevation in PT-INR, patients undergoing a liver resection demonstrated a brief hypercoagulable state, followed by normal coagulation function based on TEG. These data call into question the practice of utilizing PT-INR to guide plasma transfusion and timing of prophylactic anticoagulation after a liver resection.

BACKGROUND Deep vein thrombosis (DVT) is common after trauma. Pulmonary embolism (PE) is a feared complication of DVT. Standard doses of low-molecular-weight heparin (LMWH) are commonly used to prevent and treat DVT and PE. There is variable bioavailability of LMWH with standard therapy. The traditional concept that below-knee DVT is associated with a lower risk of subsequent PE may result in less aggressive therapy. The purposes of this study were to assess the rates of PE in above-knee versus below-knee DVT and longitudinally evaluate outcomes of DVT treated with LMWH therapy. METHODS This was a retrospective review of patients at a university Level I trauma center during the years 2005 through 2010. Patients diagnosed with lower-extremity DVT were included in this study. Patients were classified by location of lower-extremity DVT and type of LMWH therapy received. All high-risk trauma patients were evaluated with weekly duplex Doppler ultrasonography. All duplex studies were reviewed for DVT resolution or improvement. Symptomatic patients were evaluated with computed tomographic angiography to rule out PE. Demographics, total length of hospital stay, length of intensive care unit stay, and Injury Severity Score (ISS) were collected. RESULTS Three-hundred eight trauma patients with lower-extremity DVT were included. More patients developed below-knee DVT (65.6%) compared with above-knee DVT (34.4%). Increased length of hospital stay, intensive care unit stay, and higher ISS were noted in patients with above-knee DVT. More patients had below-knee DVT in the prophylactic dosing group. With LMWH therapy, three PEs occurred in patients in the prophylactic dosing group with below-knee DVT, and no PEs occurred in the therapeutic treatment group. The incidence of PE between patients with below-knee DVT compared with above-knee DVT overall was not different (3.3% and 4.7%, p = 0.59). To assess DVT outcomes, 157 of the 308 patients had serial duplex studies following diagnosis of lower-extremity DVT. The number of patients receiving either therapeutic or prophylactic LMWH was similar (51% and 49%). There was no difference in rates of resolution or improvement between LMWH dosing groups or location of DVT. CONCLUSION In screened trauma patients, below-knee DVT is more common than above-knee DVT. There was no difference in the incidence of PE between groups. Standard prophylactic and therapeutic dosing of LMWH does not affect the rates of resolution or improvement of lower-extremity DVT. Rates of resolution and improvement of DVT is not dependent of location of lower-extremity DVT. LEVEL OF EVIDENCE Therapeutic study, level IV; epidemiologic study, level III.

BACKGROUND:We performed this study to optimize reconstituted lyophilized plasma (LP) into a minimal volume fluid that provides effective hemostatic resuscitation for trauma while minimizing logistical limitations. METHODS:We performed a prospective, blinded animal study. Plasma was lyophilized following whole blood collection from anesthetized swine. The minimal volume needed for reconstitution was determined, and this solution was evaluated for safe infusion into the swine. Reconstituted LP was analyzed for electrolyte content, osmolarity, and coagulation factor activity. Twenty swine were anesthetized and subjected to a validated model of polytrauma and hemorrhagic shock (including a Grade V liver injury), then randomized to resuscitation with LP reconstituted to either 100% of the original plasma volume (100%LP) or the minimal volume LP fluid. Physiologic data were monitored, and blood loss and hematocrit were measured. Coagulation status was evaluated using thrombelastography. RESULTS:The minimal volume of reconstituted LP safe for infusion in swine was 50% of the original plasma volume (50%LP). The 50%LP had higher electrolyte concentrations, osmolarity, and increased coagulation factor activity levels by volume compared with 100%LP (p < 0.05). Blood loss, hematocrit, mean arterial pressure, and heart rate did not differ between animals receiving 100%LP (n = 10) or 50%LP (n = 10) at any time point (p > 0.05). International normalized ratio and thrombelastography parameters were not different between groups (R time, α angle, or maximal amplitude, p > 0.05). CONCLUSION:Resuscitation with 50%LP fluid was well tolerated and equally effective compared with 100%LP, with respect to physiologic and hemostatic properties. The smaller volume of fluid necessary to reconstitute hypertonic LP makes it logistically superior to 100%LP for first responders and may reduce adverse effects of large-volume resuscitation.

BACKGROUND: The purpose of this study was to determine the relationship between coagulopathy and outcome after traumatic brain injury.METHODS: Patients admitted with a traumatic brain injury were enrolled prospectively and admission blood samples were obtained for kaolin-activated thrombelastogram and standard coagulation assays. Demographic and clinical data were obtained for analysis.RESULTS: Sixty-nine patients were included in the analysis. A total of 8.7% of subjects showed hypocoagulability based on a prolonged time to clot formation (R time, > 9 min). The mortality rate was significantly higher in subjects with a prolonged R time at admission (50.0% vs 11.7%). Patients with a prolonged R time also had significantly fewer intensive care unit-free days (8 vs 27 d), hospital-free days (5 vs 24 d), and increased incidence of neurosurgical intervention (83.3% vs 34.9%).CONCLUSIONS: Hypocoagulability as shown by thrombelastography after traumatic brain injury is associated with worse outcomes and an increased incidence of neurosurgical intervention. (c) 2012 Elsevier Inc. All rights reserved.

BACKGROUND Lyophilized plasma (LP) has been shown to be as effective as fresh frozen plasma (FFP) for resuscitation in polytrauma and hemorrhagic shock. LP reconstituted with ascorbic acid is associated with suppression of cytokines when compared with fresh frozen plasma. We aimed to determine the effect of using alternate LP reconstitution acids on physiologic parameters, blood loss, coagulation, oxidative DNA damage, and proinflammatory cytokines in a polytrauma and hemorrhagic shock model. METHODS Thirty swine were anesthetized, subjected to polytrauma, hemorrhagic shock, and randomized to resuscitation with LP-ascorbic acid (AA), LP-citric acid (CA), or LP-hydrochloric acid (HCL). Physiologic data were continuously monitored, blood loss measured, and serum collected at baseline, 2 hours, and 4 hours for enzyme-linked immunosorbent assays. Measured 8-OH-2'-deoxyguanosine (8-OHdG) was a biomarker of oxidative DNA damage. RESULTS No differences were observed in physiologic measures, blood loss, or coagulation parameters. Interleukin-6 increased over time for all groups, but at 2 hours, the concentration in AA (median [minimum, maximum]: 113 ng/mL [0, 244]) was lower compared with CA (181 ng/mL [69, 314], p = 0.01) and HCL (192 ng/mL [41, 310], p = 0.03). Comparing 4 hours to baseline, a significant increase in oxidative DNA damage was observed in CA (22.9 ng/mL [16.3, 34.3] vs. 15.6 ng/mL [13.6, 26.7], p = 0.03) and HCL (19.6 ng/mL [15.7, 56.7] vs. 15.8 ng/mL [11.6, 21.4], p = 0.01) but not in AA (17.9 ng/mL [12.6, 26.9] vs. 17.1 ng/mL [11.8, 18.4], p = 0.24). CONCLUSIONS Resuscitation with AA results in decreased interleukin-6 expression and oxidative DNA damage compared with CA and HCL.

BACKGROUNDDelivery of a high ratio of plasma to packed red blood cells to patients who require massive transfusion is associated with improved survival. Hemorrhagic shock causes increased production of pro-inflammatory cytokines. These are associated with late morbidity and mortality. The use of fresh frozen plasma makes high ratio resuscitation logistically difficult and does not address dysfunctional inflammation. Lyophilized plasma (LP) is a stable powdered form of plasma that is both safe and easily reconstituted. Previous work demonstrated that LP reconstituted with ascorbic acid (AA) decreased inflammation. Whether the reduction of inflammation was associated with LP or the AA is unknown.METHODSThirty female swine were anesthetized and subjected to a multisystem combat relevant model consisting of femur fracture, controlled hemorrhage, and hypothermia. A standardized grade V liver injury was made and the animals were randomly assigned to receive LP reconstituted with AA, citric acid (CA), or hydrochloric acid (HCl). Blood was drawn at baseline and at 2 hours and 4 hours for interleukin (IL)-6, IL-8, and tumor necrosis factor-α serum concentrations measured by enzyme-linked immunosorbent assay. Lung tissue was harvested and processed for gene expression before euthanizing the animals.RESULTSNo differences were observed in mortality, baseline cytokine serum concentration, or gene expression. Enzyme-linked immunosorbent assay demonstrated that IL-6 concentration increased over time for all groups (p < 0.05), but less so at 2 hours in the AA group compared with CA and HCl.CONCLUSIONIn this animal model of trauma, hemorrhage and resuscitation, AA decreases IL-6 expression relative to CA and HCl. These findings confirm previous work from our laboratory and suggest that AA is responsible for suppression of dysfunctional inflammation in this model.

BACKGROUND:The optimal fluid strategy for the early treatment of trauma patients remains highly debated. Our objective was to determine the efficacy of an initial bolus of resuscitative fluids used in military and civilian settings on the physiologic response to uncontrolled hemorrhagic shock in a prospective, randomized, blinded animal study.METHODS:Fifty anesthetized swine underwent central venous and arterial catheterization followed by celiotomy. Grade V liver injury was performed, followed by 30 minutes of uncontrolled hemorrhage. Then, liver packing was completed, and fluid resuscitation was initiated over 12 minutes with 2 L normal saline (NS), 2 L Lactated Ringer's (LR), 250 mL 7.5% hypertonic saline with 3% Dextran (HTS), 500 mL Hextend (HEX), or no fluid (NF). Animals were monitored for 2 hours postinjury. Blood loss after initial hemorrhage, mean arterial pressure (MAP), tissue oxygen saturation (StO2), hematocrit, pH, base excess, and lactate were measured at baseline, 1 hour, and 2 hours.RESULTS:NF group had less post-treatment blood loss compared with other groups. MAP and StO2 for HEX, HTS, and LR at 1 hour and 2 hours were similar and higher than NF. MAP and StO2 did not differ between NS and NF, but NS resulted in decreased pH and base excess.CONCLUSIONS:Withholding resuscitative fluid results in the least amount of posttreatment blood loss. In clinically used volumes, HEX and HTS are equivalent to LR with regard to physiologic outcomes and superior to NF. NS did not provide a measurable improvement in outcome compared with NF and resulted in increased acidosis.

BACKGROUND:Advanced hemostatic dressings perform superior to standard gauze (SG) in animal hemorrhage models but require 2 minutes to 5 minutes application time, which is not feasible on the battlefield.METHODS:Twenty-four swine received a femoral artery injury, 30 seconds uncontrolled hemorrhage and randomization to packing with SG, Combat Gauze (CG), or Celox Gauze (XG) without external pressure. Animals were resuscitated to baseline mean arterial pressures with lactated Ringers and monitored for 120 minutes. Physiologic and coagulation parameters were collected throughout. Dressing failure was defined as overt bleeding outside the wound cavity. Tissues were collected for histologic and ultrastructural studies.RESULTS:All animals survived to study end. There were no differences in baseline physiologic or coagulation parameters or in dressing success rate (SG: 8/8, CG: 4/8, XG: 6/8) or blood loss between groups (SG: 260 mL, CG: 374 mL, XG: 204 mL; p > 0.3). SG (40 seconds ± 0.9 seconds) packed significantly faster than either the CG (52 ± 2.0) or XG (59 ± 1.9). At 120 minutes, all groups had a significantly shorter time to clot formation compared with baseline (p < 0.01). At 30 minutes, the XG animals had shorter time to clot compared with SG and CG animals (p < 0.05). All histology sections had mild intimal and medial edema. No inflammation, necrosis, or deposition of dressing particles in vessel walls was observed. No histologic or ultrastructural differences were found between the study dressings.CONCLUSIONS:Advanced hemostatic dressings do not perform better than conventional gauze in an injury and application model similar to a care under fire scenario.