Resuscitation Of Hemorrhagic Shock Research Articles

Whole Blood Storage Duration Alters Fibrinogen Levels and Thrombin Formation.

Whole blood resuscitation for hemorrhagic shock in trauma represents an opportunity to correct coagulopathy in trauma while also supplying red blood cells. The production of microvesicles in stored whole blood and their effect on its hemostatic parameters have not been described in previous literature. We hypothesized that microvesicles in aged stored whole blood are procoagulant and increase thrombin production via phosphatidylserine. Whole blood was obtained from male C57BL/6 male mice and stored in anticoagulant solution for up to 10 days. At intervals, stored whole blood underwent examination with rotational thromboelastography and platelet poor plasma was prepared for analysis of thrombin generation. Microvesicles were prepared from 10 day old whole blood aliquots and added to fresh whole blood or platelet poor plasma to assess changes in coagulation and thrombin generation. Microvesicles were treated with recombinant mouse lactadherin prior to addition to plasma to inhibit phosphatidylserine's role in thrombin generation. Aged murine whole blood had decreased fibrin clot formation compared to fresh samples with decreased plasma fibrinogen levels. Thrombin generation in plasma from aged blood increased over time of storage. The addition of microvesicles to fresh plasma resulted in increased thrombin generation compared to controls. When phosphatidylserine on microvesicles was blocked with lactadherin, there was no difference in the endogenous thrombin potential but the generation of thrombin was blunted with lower peak thrombin levels. Cold storage of murine whole blood results in decreased fibrinogen levels and fibrin clot formation. Aged whole blood demonstrates increased thrombin generation and this is due in part to microvesicle production in stored whole blood. One mechanism by which microvesicles are procoagulant is by phosphatidylserine expression on their membranes. Basic Science.

Association of freeze-dried plasma with 24-h mortality among trauma patients at risk for hemorrhage.

Blood products form the cornerstone of contemporary hemorrhage control but are limited resources. Freeze-dried plasma (FDP), which contains coagulation factors, is a promising adjunct in hemostatic resuscitation. We explore the association between FDP alone or in combination with other blood products on 24-h mortality. This is a secondary data analysis from a cross-sectional prospective observational multicenter study of adult trauma patients in the Western Cape of South Africa. We compare mortality among trauma patients at risk of hemorrhage in three treatment groups: Blood Products only, FDP + Blood Products, and FDP only. We apply inverse probability of treatment weighting and fit a multivariable Cox proportional hazards model to assess the hazard of 24-h mortality. Four hundred and forty-eight patients were included, and 55 (12.2%) died within 24 h of hospital arrival. Compared to the Blood Products only group, we found no difference in 24-h mortality for the FDP + Blood Product group (p = .40) and a lower hazard of death for the FDP only group (hazard = 0.38; 95% CI, 0.15-1.00; p = .05). However, sensitivity analyses showed no difference in 24-h mortality across treatments in subgroups with moderate and severe shock, early blood product administration, and accounting for immortal time bias. We found insufficient evidence to conclude there is a difference in relative 24-h mortality among trauma patients at risk for hemorrhage who received FDP alone, blood products alone, or blood products with FDP. There may be an adjunctive role for FDP in hemorrhagic shock resuscitation in settings with significantly restricted access to blood products.

Evaluation of hemorrhagic shock and fluid resuscitation in pigs using handless Doppler carotid artery ultrasound.

This study aimed to utilize a hemorrhagic shock pig model to compare two hemodynamic monitoring methods, pulse index continuous cardiac output (PiCCO) and spectral carotid artery Doppler ultrasound (CDU). Additionally, we sought to explore the feasibility of employing CDU as a non-invasive hemodynamic monitoring tool in the context of hemorrhagic shock and fluid resuscitation. Animal experiments. Female pigs were selected, and hemorrhagic shock was induced by rapid bleeding through an arterial sheath. Hemodynamic monitoring was conducted using both PiCCO and CDU during episodes of hemorrhagic shock and fluid resuscitation. Among the 10 female pigs studied, CDU measurements revealed a significant decrease in carotid velocity time integral (cVTI) compared to baseline values under shock conditions. During the resuscitation phase, after the mean arterial pressure (MAP) returned to its baseline level, there was no significant difference between cVTI and baseline values. A similar trend was observed for carotid peak velocity (cPV). The corrected flow time (FTc) exhibited a significant difference only at the time of shock compared to baseline values. In comparison to PiCCO, there was a significant correlation between cVTI and MAP (r = 0.616, P < 0.001), stroke volume (SV) (r = 0.821, P < 0.001), and cardiac index (CI) (r = 0.698, P < 0.001). The carotid Doppler shock index (cDSI) displayed negative correlations with MAP (r = - 0.593, P < 0.001), SV (r = - 0.761, P < 0.001), and CI (r = - 0.548, P < 0.001), while showing a positive correlation with the shock index (SI) (r = 0.647, P < 0.001). Compared to PiCCO, CDU monitoring can reliably reflect the volume status of hemorrhagic shock and fluid resuscitation. CDU offers the advantages of being non-invasive, providing real-time data, and being operationally straightforward. These characteristics make it a valuable tool for assessing and managing hemorrhagic shock, especially in resource-limited settings.

EFFECT OF MIR-21-3P ON INTESTINAL INJURY IN RATS WITH TRAUMATIC HEMORRHAGIC SHOCK RESUSCITATED WITH THE SODIUM BICARBONATE RINGER'S SOLUTION.

Background : This study aims to determine the impact and mechanism of miR-21-3p on intestinal injury and intestinal glycocalyx during fluid resuscitation in traumatic hemorrhagic shock (THS), and the different impacts of sodium lactate Ringer's solution (LRS) and sodium bicarbonate Ringer's solution (BRS) for resuscitation on intestinal damage. Methods : A rat model of THS was induced by hemorrhage from the left femur fracture. The pathological changes of intestinal tissues and glycocalyx structure were observed by hematoxylin-eosin staining and transmission electron microscope. MiR-21-3p expression in intestinal tissues was detected by real-time quantitative polymerase chain reaction. The expression of glycocalyx-, cell junction-, and PI3K/Akt/NF-κB signaling pathway-related proteins was analyzed by western blot. Results : MiR-21-3p expression was increased in THS rats, which was suppressed by resuscitation with BRS. BRS or LRS aggravated the intestinal injury and damaged intestinal glycocalyx in THS rats. The expression of SDC-1, HPA, β-catenin, MMP2, and MMP9 was upregulated, the expression of E-cad was downregulated, and the PI3K/Akt/NF-κB signaling pathway was activated in THS rats, which were further aggravated by BRS or LRS. The adverse effect of LRS was more serious than BRS. MiR-21-3p overexpression deteriorated the injury of intestinal tissues and intestinal glycocalyx; increased the expression of SDC-1, HPA, β-catenin, MMP2, and MMP9 while decreasing E-cad expression; and activated the PI3K/Akt/NF-κB signaling pathway in BRS-resuscitated THS rats. Conclusion : MiR-21-3p aggravated intestinal tissue injury and intestinal glycocalyx damage through activating PI3K/Akt/NF-κB signaling pathway in rats with THS resuscitated with BRS.

Changes in coagulation factor XIII activity during resuscitation for hemorrhagic shock.

Little is known about the coagulation activity of factor XIII (FXIII) during resuscitation for hemorrhagic shock and the effects of plasma transfusions. We performed a single-center observational study to evaluate the changes in FXIII activity during resuscitation for hemorrhagic shock. Twenty-three adult patients with hemorrhagic shock were enrolled in this study. Blood samples were drawn upon arrival (T1), at the time of hemostasis completion (T2), and on day 2 (T3). Baseline and changes in FXIII activity and the proportion of patients with adequate levels of FXIII activity (FXIII activity >70%) were evaluated. The effects of plasma transfusion on these parameters were also investigated. At T1, the median (interquartile range) FXIII activity was 53% (47-85%), which did not increase (T1 vs. T3: 53% [47-85%] vs. 63% [52-70%], P=0.8766). The proportion of patients with adequate FXIII activity decreased throughout the resuscitation period (T1, T2, and T3: 30, 34, and 21%, respectively). Plasma transfusion did not affect FXIII activity (T1 vs. T2, 66.4% [23.4] vs. 70.0% [16.2%], P=0.3956; T2 vs. T3, 72.0% [19.5] vs. 63.5% [8.6%], P=0.1161) or the proportion of adequate levels of FXIII activity at 44% at T2 and 27% at T3. FXIII activity is low during the early phase of a hemorrhagic shock. Even with plasma transfusion, FXIII levels were not adequately maintained throughout resuscitation.

Deleterious effects of plasma-derived cellular debris in a porcine model of hemorrhagic shock

BackgroundRecent studies identify large quantities of inflammatory cellular debris within Fresh Frozen Plasma (FFP). As FFP is a mainstay of hemorrhagic shock resuscitation, we used a porcine model of hemorrhagic shock and ischemia/reperfusion to investigate the inflammatory potential of plasma-derived cellular debris administered during resuscitation. MethodsThe porcine model of hemorrhagic shock included laparotomy with 35 % hemorrhage (Hem), 45 min of ischemia from supraceliac aortic occlusion with subsequent clamp release (IR), followed by protocolized resuscitation for 6 h. Cellular debris (Debris) was added to the resuscitation phase in three groups. The four groups consisted of Hem + IR (n = 4), Hem + IR + Debris (n = 3), Hem + Debris (n = 3), and IR + Debris (n = 3). A battery of laboratory, physiologic, cytokine, and outcome data were compared between groups. ResultsAs expected, the Hem + IR group showed severe time dependent decrements in organ function and physiologic parameters. All animals that included both IR and Debris (Hem + IR + Debris or IR + Debris) died prior to the six-hour end point, while all animals in the Hem + IR and Hem + Debris survived. Cytokines measured at 30–60 min after initiation of resuscitation revealed significant differences in IL-18 and IL-1β between all groups. ConclusionsIschemia and reperfusion appear to prime the immune system to the deleterious effects of plasma-derived cellular debris. In the presence of ischemia and reperfusion, this model showed the equivalency of 100 % lethality when resuscitation included quantities of cellular debris at levels routinely administered to trauma patients during transfusion of FFP. A deeper understanding of the immunobiology of FFP-derived cellular debris is critical to optimize resuscitation for hemorrhagic shock.

EXCHANGE TRANSFUSION WITH VS -101: A NEW PEGYLATED-HB DESIGNED TO RESTORE PERFUSION AND INCREASE O 2 CARRYING CAPACITY.

Blood products are the current standard for resuscitation of hemorrhagic shock. However, logistical constraints of perishable blood limit availability and prehospital use, meaning alternatives that provide blood-like responses remain an area of active investigation and development. VS-101 is a new PEGylated human hemoglobin-based oxygen carrier that avoids the logistical hurdles of traditional blood transfusion. This study sought to determine the safety and ability of VS -101 to maintain circulatory function and capillary oxygen delivery in a severe (50%) exchange transfusion (ET) model. Anesthetized, male Sprague Dawley rats were prepared for cardiovascular monitoring and phosphorescence quenching microscopy of interstitial fluid oxygen tension (P ISFo2 ) in the spinotrapezius muscle. Fifty-percent isovolemic ET of estimated total blood volume with either lactated Ringer's solution (LRS, n = 8) or VS -101 (n = 8) at 1 mL/kg/min was performed, and animals were observed for 240 min. VS -101 maintained P ISFo2 at baseline with a transient 18 ± 4 mm Hg decrease ( P < 0.05) in mean arterial pressure (MAP). In contrast, ET with LRS decreased P ISFo2 by approximately 50% ( P < 0.05) and MAP by 74 ± 10 mm Hg ( P < 0.05). All VS -101 animals survived 240 min, the experimental endpoint, while 100% of LRS animals expired by 142 min. VS -101 animals maintained normal tissue oxygenation through 210 min, decreasing by 25% ( P < 0.05 vs. baseline) thereafter, likely from VS -101 vascular clearance. No arteriolar vasoconstriction was observed following VS -101 treatment. In this model of severe ET, VS -101 effectively maintained blood pressure, perfusion, and P ISFo2 with no vasoconstrictive effects. Further elucidation of these beneficial resuscitation effects of VS -101 is warranted to support future clinical trials.

War at Sea: Burn Care Challenges—Past, Present and Future

Throughout history, seafarers have been exposed to potential thermal injuries during naval warfare; however, injury prevention, including advances in personal protective equipment, has saved lives. Thankfully, burn injuries have decreased over time, which has resulted in a significant clinical skills gap. Ships with only Role 1 (no surgical capability) assets have worse outcomes after burn injury compared to those with Role 2 (surgical capability) assets. To prepare for future burn care challenges during a war at sea, Military Medicine must re-learn the lessons of World War I and World War II. Burn injuries do not occur in isolation during war and are associated with concomitant traumatic injuries. To care for burn casualties at sea, there is an urgent need to increase the availability of whole blood and dried plasma, resuscitation fluids that were ubiquitous throughout the naval force during World War II for both hemorrhagic and burn shock resuscitation. Furthermore, those providing trauma care at sea require formal burn care training and skills sustainment experiences in the clinical management of Burn, Trauma, and Critical Care patients. While burn education, training, and experience must be improved, modern high-energy weapons systems and anti-ship ballistic missiles necessitate concurrent investments in prevention, countermeasures, and personal protective equipment to decrease the likelihood of burn injury and damage resulting from these attacks.

ASSESSMENT OF ABNORMAL SKELETAL MUSCLE PERFUSION BY CONTRAST-ENHANCED ULTRASOUND WITH PARAMETRIC IMAGING IN RATS AFTER SEVERE INJURY, HEMORRHAGIC SHOCK, AND WHOLE BLOOD RESUSCITATION.

Background: After severe injury, optical measures of microvascular blood flow (MBF) decrease and do not normalize with resuscitation to normal blood pressure. These changes are associated with organ dysfunction, coagulopathy, and death. However, the pathophysiology is not well understood. Several possible pathways could also contribute to the development of trauma-induced coagulopathy (TIC). A small-animal model of trauma-related MBF derangement that persists after resuscitation and includes TIC would facilitate further study. Parametric contrast-enhanced ultrasound (CEUS) is particularly advantageous in this setting, because it noninvasively assesses MBF in large, deep vascular beds. We sought to develop such a model, measuring MBF with CEUS. Methods: Sixteen male Sprague-Dawley rats were anesthetized, ventilated, and cannulated. Rats were subjected to either no injury (sham group) or a standardized polytrauma and pressure-targeted arterial catheter hemorrhage with subsequent whole blood resuscitation (trauma group). At prespecified time points, CEUS measurements of uninjured quadriceps muscle, viscoelastic blood clot strength, and complete blood counts were taken. Results: After resuscitation, blood pressure normalized, but MBF decreased and remained low for the rest of the protocol. This was primarily driven by a decrease in blood volume with a relative sparing of blood velocity. Viscoelastic blood clot strength and platelet count also decreased and remained low throughout the protocol. Conclusion: We present a rat model of MBF derangement in uninjured skeletal muscle and coagulopathy after polytrauma that persists after resuscitation with whole blood to normal macrohemodynamics. Parametric CEUS analysis shows that this change is primarily due to microvascular obstruction. This platform can be used to develop a deeper understanding of this important process.

Sodium bicarbonate Ringer's solution for hemorrhagic shock: A meta-analysis comparing crystalloid solutions

BackgroundThe choice of fluid resuscitation in Traumatic Hemorrhagic shock (THS) remains a critical aspect of patient management. Bicarbonated Ringers solution (BRS) has shown promise due to its composition resembling human Extracellular Fluid and its potential benefits on hemodynamics. ObjectiveTo evaluate the efficacy, mortality rates, hemodynamic effects, and adverse outcomes of Sodium Bicarbonate Ringer's Solution in the treatment of hemorrhagic shock, as compared to other relevant interventions. MethodA comprehensive examination of the available literature was performed by conducting systematic searches in prominent databases such as Cochrane, EMBASE, MEDLINE, and PubMed. The process employed predefined criteria to extract relevant data and evaluate the quality of the studies. The outcome measures considered encompassed survival rates, mortality, mean arterial pressure (MAP), heart rate (HR), and adverse events. ResultThe meta-analysis of three studies showed that compared to the other crystalloids, the use of BRS had an odds ratio for survival of 1.86 (95% CI: 0.94, 3.71; p = 0.08; I2 = 0%), an odds ratio for total adverse events of 0.14 (95% CI: 0.06, 0.35; p < 0.0001; I2 = 22%), a mean difference in heart rate of −4.49 (95% CI: −7.55, −1.44; p = 0.004; I2 = 13%), and a mean difference in mean arterial pressure of 2.31 (95% CI: −0.85, 5.47; p = 0.15; I2 = 66%). ConclusionBRS demonstrated a significant reduction in complications, including adult respiratory distress syndrome (ARDS), Multiple Organ Dysfunction (MODS), and Total Adverse Effects, when compared to other solutions in the treatment of THS. Additionally, THS patients resuscitated with BRS experienced a notable decrease in heart rate. The findings suggest BRS may contribute to organ stability and potential survival improvement due to its similarity to human Extracellular Fluid and minimal impact on the liver.

The Molecular Size of Bioengineered Oxygen Carriers Determines Tissue Oxygenation in a Hypercholesterolemia Guinea Pig Model of Hemorrhagic Shock and Resuscitation.

Polymerized human hemoglobin (PolyhHb) has shown promise in preclinical hemorrhagic shock settings. Different synthetic and purification schemes can control the size of PolyhHbs, yet research is lacking on the impact of polymerized hemoglobin size on tissue oxygenation following hemorrhage and resuscitation in specialized animal models that challenge their resuscitative capabilities. Pre-existing conditions that compromise the vasculature and end organs, such as the liver, may limit the effectiveness of resuscitation and exacerbate the toxicity of these molecules, which is an important but minimally explored therapeutic dimension. In this study, we compared the effective oxygen delivery of intermediate molecular weight PolyhHb (PolyhHb-B3; 500-750 kDa) to high molecular weight PolyhHb (PolyhHb-B4; 750 kDa-0.2 μm) for resuscitative effectiveness in guinea pig models subjected to hemorrhagic shock. We evaluated how the size of PolyhHb impacts hemodynamics and tissue oxygenation in normal guinea pigs and guinea pigs on an atherogenic diet. We observed that while PolyhHb-B3 and -B4 equivalently restore hemodynamic parameters of normal-dieted guinea pigs, high-fat-dieted guinea pigs resuscitated with PolyhHb-B4 have lower mean arterial pressures, impaired tissue oxygenation, and higher plasma lactate levels than those receiving PolyhHb-B3. We characterized the plasma of these animals following resuscitation and found that despite similar oxygen delivery kinetics, circulating PolyhHb-B3 and -B4 demonstrated a size-dependent increase in the plasma viscosity, consistent with impaired perfusion in the PolyhHb-B4 transfusion group. We conclude that intermediate-sized PolyhHbs (such as -B3) are ideal for further research given the effective resuscitation of hemorrhagic shock based on tissue oxygenation in hypercholesterolemic guinea pigs.

Sidestream dark field imaging and biomarker evaluation reveal minimal significant changes to the microcirculation and glycocalyx in a canine hemorrhagic shock model.

To investigate the effects of hemorrhagic shock and fresh whole blood resuscitation on the microcirculation and endothelial glycocalyx using sidestream dark field (SDF) imaging and plasma biomarkers. 8 purpose-bred dogs. Pressure-targeted hemorrhagic shock was induced in anesthetized dogs. SDF measurement of perfused boundary region and microcirculatory variables (RBC flow, total vessel density, and relative and absolute capillary blood volume), biomarker measurement (heparan sulfate, hyaluronan, VE-cadherin, and syndecan-1), mean arterial blood pressure, and cardiac output measurement were performed before anesthesia (TP0), after induction (TP1), after hemorrhagic shock (TP2), and after 50% retransfusion (TP3) and 100% retransfusion (TP4). At TP1, TP2, TP3, and TP4, mean arterial blood pressure was 74.25 ± 7.17 mm Hg, 49.50 ± 13.74 mm Hg, 63.50 ± 13.29 mm Hg, and 71.38 ± 8.77 mm Hg, and cardiac output was 2.57 ± 1.01 L/min, 0.8 ± 0.36 L/min, 1.81 ± 0.57 L/min, and 2.93 ± 1.22 L/min, respectively. Heparan sulfate, hyaluronan, syndecan-1, and VE-cadherin ranges were 24.80 to 77.72 ng/mL, 5.77 to 105.06 ng/mL, below detection to 1,545.69 pg/mL, and 0 to 2.52 ng/mL, respectively. Perfused boundary region, RBC flow, total vessel density, and relative and absolute capillary blood volume ranges were 1.75 to 2.68 µm, 89.6 to 584.5 µm/s, 51.7 to 1,914.3 mm/m2, 0.94 to 1.53 103 μm3, and 1.50 to 94.30 103 μm3, respectively. Heparan sulfate decreased significantly over time (P = .016). No significant differences were found for microcirculatory variables, perfused boundary regions, or other biomarkers. This was the first study to assess microvascular dysfunction and endothelial shedding in a canine hemorrhagic shock model using SDF microscopy (Glycocheck) and plasma biomarkers. Further studies are needed to determine clinical relevance.

Clinical Use of Canine Thawed Refrigerated Plasma: A Historical Case Series.

Thawed plasma (TP) refers to defrosted fresh frozen plasma stored refrigerated. TP is used in human medicine for the rapid provision of coagulation factors and resuscitation of haemorrhagic shock, but its use in dogs is poorly described. The objectives of this historical case series were to describe the reasons for TP transfusion, treatment outcomes, and adverse events associated with canine TP transfusions in a veterinary teaching hospital. We hypothesised that TP would be used most commonly for the treatment of haemorrhage secondary to anticoagulant rodenticide intoxication and trauma. Blood bank plasma transfusion logs were searched to identify dogs that received at least one unit of TP between December 2015 and June 2021. Briefly, 166 dogs received a total of 262 units of TP. Anticoagulant rodenticide intoxication (37/166, 22.3%) was the most common reason for transfusion, followed by traumatic haemorrhage (23, 13.9%) and spontaneous haemoperitoneum (22, 13.2%). The majority of dogs received one unit of TP (111/166, 67.1%) and pRBCs were commonly simultaneously transfused with TP (65, 39.2%). Severe prolongations of prothrombin time and activated partial thromboplastin time were reduced following TP transfusions. Allergic reactions were the most common transfusion reaction (19/166, 11.4%). Most dogs survived to discharge (101/166, 60.8%).

Polyoxazoline-conjugated porcine serum albumin as an artificial plasma expander for dogs

Veterinary medicine has made tremendous progress for domestic dogs, which are irreplaceable family members enriching human life. Nevertheless, no adequate supply system exists for their blood products. This study examined the synthesis, structure, safety, and efficacy of poly(2-ethyl-2-oxazoline)-conjugated porcine serum albumin (POx-PSA) as an artificial plasma expander for dogs. The aqueous POx-PSA solution showed moderately high colloid osmotic pressure and good blood cell compatibility. Actually, lyophilized powder stored for 1 year can regenerate into a homogeneous solution. The circulation half-life of POx-PSA in rats was 2.1-fold longer than that of naked PSA. Rats produced neither anti-PSA IgG antibody nor anti-POx IgG antibody, which suggests excellent immunological stealth properties of POx-PSA. Complete resuscitation of hemorrhagic shock in rats was achieved soon after injection of POx-PSA solution. Serum biochemistry tests and histopathological observations indicated no abnormality in the related organs. When POx-PSA was administered to dogs intravenously, (i) no serum biochemical or hematological alteration was observed, also (ii) no overt deterioration of animal health was observed. These results indicate that POx-PSA has potential as an artificial plasma expander for dogs.

Microcirculatory effects of rewarming in experimental hemorrhagic shock.

Rewarming is a recommended therapy during the resuscitation of hypothermic patients with hemorrhagic shock. In experimental models, however, it increases inflammatory response and mortality. Although microcirculation is potential target of inflammation, the microvascular effects of rewarming during the resuscitation of hemorrhagic shock have not been studied. Our goal was to assess the systemic and microcirculatory effects of an increase in core temperature (T°) during the retransfusion of hemorrhagic shock in sheep. Our hypothesis was that rewarming could hamper microcirculation. In anesthetized and mechanically ventilated sheep, we measured systemic, intestinal, and renal hemodynamics and oxygen transport. O2 consumption (VO2) and respiratory quotient were measured by indirect calorimetry. Cortical renal, intestinal villi and sublingual microcirculation were assessed by IDF-videomicroscopy. After basal measurements, hemorrhagic shock was induced and T° was reduced to ~33°C. After 1h of shock and hypothermia, blood was retransfused and Ringer lactate solution was administered to prevent arterial hypotension. In the control group (n=12), T° was not modified, while in the intervention (rewarming) group, it was elevated ~3°C. Measurements were repeated after 1h. During shock, both groups showed similar systemic and microvascular derangements. After retransfusion, VO2 remained decreased compared to baseline in both groups, but was lower in the control compared to the rewarming group. Perfused vascular density has a similar behavior in both groups. Compared to baseline, it remained reduced in peritubular (control vs. rewarming group, 13.8 [8.7-17.5] vs. 15.7 [10.1-17.9] mm/mm2, PNS) and villi capillaries (14.7 [13.6-16.8] vs. 16.3 [14.2-16.9] mm/mm2, PNS), and normalized in sublingual mucosa (19.1 [16.0-20.3] vs. 16.6 [14.7-17.2] mm/mm2, PNS). This is the first experimental study assessing the effect of rewarming on systemic, regional, and microcirculatory perfusion in hypothermic hemorrhagic shock. We found that a 3°C increase in T° neither improved nor impaired the microvascular alterations that persisted after retransfusion. In addition, sublingual mucosa was less susceptible to reperfusion injury than villi and renal microcirculation.

Adaptive closed-loop resuscitation controllers for hemorrhagic shock resuscitation.

After hemorrhage control, fluid resuscitation is the most important intervention for hemorrhage. Even skilled providers can find resuscitation challenging to manage, especially when multiple patients require care. In the future, attention-demanding medical tasks like fluid resuscitation for hemorrhage patients may be reassigned to autonomous medical systems when availability of skilled human providers is limited, such as in austere military settings and mass casualty incidents. Central to this endeavor is the development and optimization of control architectures for physiological closed-loop control systems (PCLCs). PCLCs can take many forms, from simple table look-up methods to widely used proportional-integral-derivative or fuzzy-logic control theory. Here, we describe the design and optimization of multiple adaptive resuscitation controllers (ARCs) that we have purpose-built for the resuscitation of hemorrhaging patients. Three ARC designs were evaluated that measured pressure-volume responsiveness using different methodologies during resuscitation from which adapted infusion rates were calculated. These controllers were adaptive in that they estimated required infusion flow rates based on measured volume responsiveness. A previously developed hardware-in-loop test platform was used to evaluate the ARCs implementations across several hemorrhage scenarios. After optimization, we found that our purpose-built controllers outperformed traditional control system architecture as embodied in our previously developed dual-input fuzzy-logic controller. Future efforts will focus on engineering our purpose-built control systems to be robust to noise in the physiological signal coming to the controller from the patient as well as testing controller performance across a range of test scenarios and in vivo.

Dexmedetomidine improves acute lung injury by activating autophagy in a rat hemorrhagic shock and resuscitation model

Dexmedetomidine (DEX) can reduce lung injury in a hemorrhagic shock (HS) resuscitation (HSR) model in rats by inhibiting inflammation. Here, we aimed to investigate if these effects of DEX are due to autophagy activation. Therefore, we established HSR rat models and divided them into four groups. HS was induced using a blood draw. The rats were then resuscitated by reinjecting the drawn blood and saline. The rats were sacrificed 24 h after resuscitation. Lung tissues were harvested for histopathological examination, determination of wet/dry lung weight ratio, and detection of the levels of autophagy-related marker proteins LC3, P62, Beclin-1, and the ATG12-ATG5 conjugate. The morphological findings of hematoxylin and eosin staining in lung tissues and the pulmonary wet/dry weight ratio showed that lung injury improved in HSR + DEX rats. However, chloroquine (CQ), an autophagy inhibitor, abolished this effect. Detecting the concentration of autophagy-related proteins showed that DEX administration increased LC3, ATG12-ATG5, and Beclin-1 expression and decreased P62 expression. The expression levels of these proteins were similar to those in the HSR group after CQ + DEX administration. In summary, DEX induced autophagic activation in an HSR model. These findings suggest that DEX administration partially ameliorates HSR-induced lung injury via autophagic activation.

The Whole Story: A Comprehensive Review of Whole Blood Resuscitation for Hemorrhagic Shock

The Whole Story: A Comprehensive Review of Whole Blood Resuscitation for Hemorrhagic Shock

SULFORAPHANE ADMINISTRATION AFTER HEMORRHAGIC SHOCK/RESUSCITATION IN MICE REDUCES THE SECRETION OF INFLAMMATORY CYTOKINES AND INCREASES THE IMMUNOCOMPETENCE OF SPLENIC MACROPHAGES.

Objective : The purpose of this study was to investigate the immunomodulatory effects of sulforaphane (SFN), a nuclear factor erythroid 2-related factor (Nrf2) pathway activator, on splenic macrophages' immunocompetence after hemorrhagic shock/resuscitation (HS/R). Methods : Male C57/BL6 wild-type mice (n = 6 per group) were subjected to either pressure-controlled HS (MAP, 35-45 mm Hg) or a sham procedure surgery (without HS). After 90 minutes of HS, fluid resuscitation with withdrawn blood and 0.9% NaCl was performed. Sulforaphane (50 mg/kg of body weight) was applied intraperitoneally immediately after the resuscitation phase as well as 24 and 48 h thereafter, depending on group allocation. The mice were killed at 6, 24, and 72 h after resuscitation. After killing, spleens were harvested to perform Nrf2 immunofluorescence histology. Splenic macrophages were isolated and cultured to measure cytokine secretion in the cell culture supernatant. Furthermore, macrophages isolated after 24-hour resuscitation were treated with 100 ng/mL of bacterial LPS to measure immunocompetence. Matrix-assisted laser desorption/ionization mass spectrometry imaging was performed to verify the distribution of SFN in the spleen after intraperitoneal injection. Results : We showed that administered SFN reached the spleen within the first hour after administration. Furthermore, we identified that SFN increased splenic Nrf2 activation and decreased cytokine expression in splenic macrophages after HS/R. In addition, we showed that SFN exhibited splenic anti-inflammatory properties of macrophages in vitro (IL-6/IL-10-ratio of the HS/R group: 51.79 ± 9.99 [at 6 h] and 15.70 ± 3.35 [at 24 h] vs. HS/R + SFN group: 20.54 ± 5.35 [at 6 h] and 8.60 ± 2.37 [at 24 h], P < 0.05). Furthermore, SFN improved in vitro splenic macrophage immunocompetence after HS/R, as evidenced by the increased secretion of inflammatory cytokines in response to LPS stimulation in vitro . Conclusions : Our study shows that SFN can reduce inflammatory cytokines secreted by splenic macrophages after HS/R and increase their immunocompetence toward a more anti-inflammatory profile.

1172: EVALUATION OF SHELF-STABLE BLOOD PRODUCTS FOR RESUSCITATION IN A CANINE MODEL OF HEMORRHAGIC SHOCK

Introduction: Hemorrhagic shock is a major cause of morbidity and mortality in trauma patients. Current resuscitation methods use blood products that require temperature control and have a limited lifespan, which present significant limitations for use in rural areas and combat zones. This study examined whether shelf stable blood product resuscitation strategies leveraging freeze-dried plasma (FDP), hemoglobin based oxygen carrier (HBOC), and lyophilized platelets (LP) provide an alternative to conventional resuscitation strategies in a canine model. We hypothesized that a combination of HBOC and FDP with or without LP would be non-inferior to chilled whole blood (CWB) for hemorrhagic shock resuscitation. Methods: Seven dogs were anesthetized and subjected to controlled hemorrhage of up to 40% of their blood volume (T0) over one hour to achieve a mean arterial blood pressure of 35-50 mmHg. They were maintained in shock for 45 minutes and were then randomized to receive: CWB, FDP+HBOC, or FDP+HBOC+LP over 30 minutes (T105-135). Citrated blood was collected at T0, T105, T135, and T180 for thromboelastography (TEG 5000). Samples were run in duplicates with kaolin activation to measure reaction time (r), kinetic time (k), alpha angle (alpha), and maximum amplitude (MA). Between-group comparisons were performed using a Kruskal-Wallis ANOVA and a Bonferroni correction. Results are reported as mean +/- standard deviation. Results: There was no difference in baseline parameters between groups or in TEG values between groups at the end of shock T0 and T105. There was a difference in alpha and MA between groups at T135 (p= 0.02 for both) and T180 (p=0.02 and 0.002, respectively). Specifically, alpha and MA were lower in the FDP+HBOC+LP group (alpha: 54.9 +/- 6.6 deg; MA: 43.5 +/- 11.5 mm) than in the CWB group (alpha: 64.4 +/- 5.2 deg; MA: 58.2 +/- 5.1 mm). There was no difference in r, alpha, and k between groups at any time point. Conclusions: In this canine model of controlled hemorrhage, TEG parameters between FDP+HBOC and CWB were not different. We demonstrated evidence of reduced coagulation function in FDP+HBOC+LP. The biological relevance of those findings should be determined in an uncontrolled hemorrhage model. Resuscitation with shelf-stable products appeared safe and satisfactory in this model.