Uncontrolled hemorrhagic shock results in a hypercoagulable state modulated by initial fluid resuscitation regimens.

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.

Hyperosmolar reconstituted lyophilized plasma is an effective low-volume hemostatic resuscitation fluid for trauma.

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.

The effects of location and low-molecular-weight heparin administration on deep vein thrombosis outcomes in trauma patients.

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.

Effects of In vitro hemodilution, hypothermia and rFVIIa addition on coagulation in human blood.

INTRODUCTION: Coagulopathy can occur after hemorrhage, trauma and resuscitation, and has been associated with dilution of coagulation factors and hypothermia. Recombinant activated Factor VII (rFVIIa) has been used, often as a last resort, to improve hemostasis in trauma/hemorrhage patients with coagulopathy. The aim of this study was to further characterize the effects of rFVIIa on various coagulation parameters and the influence of temperature and hemodilution. METHODS: WHOLE BLOOD FROM HEALTHY HUMAN VOLUNTEERS WAS INCUBATED IN A COMBINATION OF THREE CONDITIONS: undiluted or diluted 40% with either lactated Ringer's solution or Hextend, at 37°C or 34°C, and with and without rFVIIa (1.26 µg/ml, final concentration). Blood or plasma, as appropriate, was measured for coagulation by thrombin generation, thromboelastography (TEG), prothrombin Time (PT) and activated partial thromboplastin (aPTT). RESULTS: Incubation of plasma at 34°C significantly elevated thrombin generation, and prolonged PT and aPTT. Dilution of blood or plasma with 40% Hextend, but not lactated Ringer's, had a significant effect on TEG parameters, and prolonged PT and aPTT. In control conditions (37°C, 0 dilution), the addition of rFVIIa to human plasma or whole blood led to a significant change in all TEG parameters, and Lagtime for thrombin generation, but not to PT or aPTT. CONCLUSION: Theses data show that thrombin generation is affected by hypothermia, but not 40% dilution. TEG is affected by 40% dilution with Hextend, but not by hypothermia. PT and aPTT are significantly affected by both hypothermia and dilution. Recombinant FVIIa caused a greater change in thrombin generation at 34°C as compared to 37°C, and a greater change in PT at 40% dilution, suggesting that the effect of rFVIIa on coagulation is both temperature and dilution dependant.

Lyophilized plasma reconstituted with ascorbic acid suppresses inflammation and oxidative DNA damage.

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.

Lyophilized plasma with ascorbic acid decreases inflammation in hemorrhagic shock.

BACKGROUND: Delivery 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. METHODS: Thirty 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. RESULTS: No 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. CONCLUSION: In 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.

Splenectomy leads to a persistent hypercoagulable state after trauma.

BACKGROUND: It was hypothesized that splenectomy following trauma results in hypercoagulability. METHODS: A prospective, nonrandomized, single-center study was performed to evaluate coagulation parameters in trauma patients with splenic injury. RESULTS: Patients with splenectomy (n = 30) and nonoperative management (n = 50) were enrolled. Splenectomy patients were older, had higher Injury Severity Scores, and had longer intensive care unit and hospital stays (P < .05). Splenectomy patients had significantly increased white blood cell counts and platelet counts at baseline and follow-up (P < .01). Fibrinogen was initially elevated in both groups and remained elevated in the splenectomy group (P < .05). Tissue plasminogen activator, plasminogen activator inhibitor-1, and activated partial thromboplastin time were higher in splenectomy patients only at baseline (P < .05). Baseline thromboelastography showed faster fibrin cross-linking and enhanced fibrinolysis following splenectomy (P < .05). Only clot strength was greater at follow-up in the splenectomy group (P < .01). Deep venous thrombosis developed in 7% of splenectomy patients and no control patients (P = .03). CONCLUSIONS: A significant difference in deep venous thrombosis formation was noted, and coagulation assays indicated persistent hypercoagulability following splenectomy for trauma.