Hemorrhagic shock

Cell death in acute lung injury: caspase-regulated apoptosis, pyroptosis, necroptosis, and PANoptosis

There has been abundant research on the variety of programmed cell death pathways. Apoptosis, pyroptosis, and necroptosis under the action of the caspase family are essential for the innate immune response. Caspases are classified into inflammatory caspase-1/4/5/11, apoptotic caspase-3/6/7, and caspase-2/8/9/10. Although necroptosis is not caspase-dependent to transmit cell death signals, it can cross-link with pyroptosis and apoptosis signals under the regulation of caspase-8. An increasing number of studies have reiterated the involvement of the caspase family in acute lung injuries caused by bacterial and viral infections, blood transfusion, and ventilation, which is influenced by noxious stimuli that activate or inhibit caspase engagement pathways, leading to subsequent lung injury. This article reviews the role of caspases implicated in diverse programmed cell death mechanisms in acute lung injury and the status of research on relevant inhibitors against essential target proteins of the described cell death mechanisms. The findings of this review may help in delineating novel therapeutic targets for acute lung injury.

Schisandrin a Ameliorates Cardiac Injury and Dysfunction Induced by Hemorrhagic Shock via Activating the Nrf2 Signaling Pathway

Hemorrhagic shock (HS) is a critical condition with high mortality caused by acute blood loss. Cardiac injury and dysfunction induced by HS is a major factor associated with the poor prognosis of affected patients. Schisandrin A (Sch A), a dibenzocyclooctadiene lignan extracted from Fructus schisandrae, exhibits multiple biological activities, including anti-inflammatory, and antioxidant effects. However, the effect of Sch A on HS-caused cardiac injury and its underlying mechanism still lack research. In this study, we established an HS rat model through blood loss from the femoral artery and monitoring mean arterial pressure (MAP) followed by fluid resuscitation. Our findings suggested that cardiac dysfunction and pathological injury were induced by HS and attenuated by Sch A treatment in a dose-dependent manner. Apoptosis in cardiac tissue was promoted by HS, but suppressed after administration of Sch A by decreasing the protein expressions of cleaved-caspase-3 and -9. Moreover, excessive ROS production induced by HS was mitigated by Sch A, and the levels of oxidative stress indicators were improved by Sch A. Additionally, HS triggered the reduction of mitochondrial membrane potential (MMP), and led to mitochondrial dysfunction. Sch A reversed this effect of HS on mitochondria. The transformation of cytochrome c (Cyto c) induced by HS was also restored by Sch A. Importantly, the activation of the Nrf2 signaling pathway mediated the protective effects of Sch A against cardiac injury induced by HS. In conclusion, it was found that Sch A ameliorated HS-induced cardiac injury and dysfunction through suppressing apoptosis and oxidative stress, as well as alleviating mitochondrial dysfunction via the Nrf2 signaling pathway.

The UK resuscitative endovascular balloon occlusion of the aorta in trauma patients with life-threatening torso haemorrhage: the (UK-REBOA) multicentre RCT

Background

The most common cause of preventable death after injury is haemorrhage. Resuscitative endovascular balloon occlusion of the aorta is intended to provide earlier, temporary haemorrhage control, to facilitate transfer to an operating theatre or interventional radiology suite for definitive haemostasis.

Objective

To compare standard care plus resuscitative endovascular balloon occlusion of the aorta versus standard care in patients with exsanguinating haemorrhage in the emergency department.

Design

Pragmatic, multicentre, Bayesian, group-sequential, registry-enabled, open-label, parallel-group randomised controlled trial to determine the clinical and cost-effectiveness of standard care plus resuscitative endovascular balloon occlusion of the aorta, compared to standard care alone.

Setting

United Kingdom Major Trauma Centres.

Participants

Trauma patients aged 16 years or older with confirmed or suspected life-threatening torso haemorrhage deemed amenable to adjunctive treatment with resuscitative endovascular balloon occlusion of the aorta.

Interventions

Participants were randomly assigned 1 : 1 to: standard care, as expected in a major trauma centre standard care plus resuscitative endovascular balloon occlusion of the aorta.

Main outcome measures

Primary: Mortality at 90 days. Secondary: Mortality at 6 months, while in hospital, and within 24, 6 and 3 hours; need for haemorrhage control procedures, time to commencement of haemorrhage procedure, complications, length of stay (hospital and intensive care unit-free days), blood product use. Health economic: Expected United Kingdom National Health Service perspective costs, life-years and quality-adjusted life-years, modelled over a lifetime horizon.

Data sources

Case report forms, Trauma Audit and Research Network registry, NHS Digital (Hospital Episode Statistics and Office of National Statistics data).

Results

Ninety patients were enrolled: 46 were randomised to standard care plus resuscitative endovascular balloon occlusion of the aorta and 44 to standard care. Mortality at 90 days was higher in the standard care plus resuscitative endovascular balloon occlusion of the aorta group (54%) compared to the standard care group (42%). The odds ratio was 1.58 (95% credible interval 0.72 to 3.52). The posterior probability of an odds ratio > 1 (indicating increased odds of death with resuscitative endovascular balloon occlusion of the aorta) was 86.9%. The overall effect did not change when an enthusiastic prior was used or when the estimate was adjusted for baseline characteristics. For the secondary outcomes (3, 6 and 24 hours mortality), the posterior probability that standard care plus resuscitative endovascular balloon occlusion of the aorta was harmful was higher than for the primary outcome. Additional analyses to account for intercurrent events did not change the direction of the estimate for mortality at any time point. Death due to haemorrhage was more common in the standard care plus resuscitative endovascular balloon occlusion of the aorta group than in the standard care group. There were no serious adverse device effects. Resuscitative endovascular balloon occlusion of the aorta is less costly (probability 99%), due to the competing mortality risk but also substantially less effective in terms of lifetime quality-adjusted life-years (probability 91%).

Limitations

The size of the study reflects the relative infrequency of exsanguinating traumatic haemorrhage in the United Kingdom. There were some baseline imbalances between groups, but adjusted analyses had little effect on the estimates.

Conclusions

This is the first randomised trial of the addition of resuscitative endovascular balloon occlusion of the aorta to standard care in the management of exsanguinating haemorrhage. All the analyses suggest that a strategy of standard care plus resuscitative endovascular balloon occlusion of the aorta is potentially harmful.

Future work

The role (if any) of resuscitative endovascular balloon occlusion of the aorta in the pre-hospital setting remains unclear. Further research to clarify its potential (or not) may be required.

Trial registration

This trial is registered as ISRCTN16184981.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 14/199/09) and is published in full in Health Technology Assessment; Vol. 28, No. 54. See the NIHR Funding and Awards website for further award information.

Systemic acylcarnitine levels are affected in response to multiple injuries and hemorrhagic shock: An analysis of lipidomic changes in a standardized porcine model

INTRODUCTION

Along with recent advances in analytical technologies, tricarboxylic acid-cycle intermediates are increasingly identified as promising makers for cellular ischemia and mitochondrial dysfunction during hemorrhagic shock. For traumatized patients, the knowledge of the role of lipid oxidation substrates is sparse. In this study, we aimed to analyze the dynamics of systemic acylcarnitine (AcCa) release in a standardized polytrauma model with hemorrhagic shock.

METHODS

Fifty-two male pigs (50 ± 5 kg) were randomized into two groups: group isolated fracture was subject to a standardized femur shaft fracture, and group polytrauma was subject to a femur fracture, followed by blunt chest trauma, liver laceration, and a pressure-controlled hemorrhagic shock for 60 minutes. Resuscitation was performed with crystalloids. Fractures were stabilized by intramedullary nailing. Venous samples were collected at six time points (baseline, trauma, resuscitation, 2 hours, 4 hours, and 6 hours). Lipidomic analysis was performed via liquid chromatography coupled mass spectrometry. Measurements were collated with clinical markers and near-infrared spectrometry measurements of tissue perfusion. Longitudinal analyses were performed with linear mixed models, and Spearman's correlations were calculated. A p value of 0.05 was defined as threshold for statistical significance.

RESULTS

From a total of 303 distinct lipids, we identified two species of long-chain AcCas. Both showed a highly significant ( p < 0.001) twofold increase after hemorrhagic shock in group polytrauma that promptly normalized after resuscitation. This increase was associated with a significant decrease of the base excess ( p = 0.005), but recovery after resuscitation was faster. For both AcCas, there were significant correlations with decreased muscle tissue oxygen delivery ( p = 0.008, p = 0.003) and significant time-lagged correlations with the increase of creatine kinase ( p < 0.001, p < 0.001).

CONCLUSION

Our results point to plasma AcCas as a possible indicator for mitochondrial dysfunction and cellular ischemia in hemorrhagic shock. The more rapid normalization after resuscitation in comparison with acid base changes may warrant further investigation.

A NOVEL OLIGONUCLEOTIDE MRNA MIMIC ATTENUATES HEMORRHAGE-INDUCED ACUTE LUNG INJURY

ABSTRACT

Hemorrhagic shock (HS) is accompanied by a pronounced activation of the inflammatory response in which acute lung injury (ALI) is one of the most frequent consequences. Among the pivotal orchestrators of this inflammatory cascade, extracellular cold-inducible RNA-binding protein (eCIRP) emerges as a noteworthy focal point, rendering it as a promising target for the management of inflammation and tissue injury. Recently, we have reported that oligonucleotide poly(A) mRNA mimic termed A 12 selectively binds to the RNA binding region of eCIRP and inhibits eCIRP binding to its receptor TLR4. Furthermore, in vivo administration of eCIRP induces lung injury in healthy mice and that mouse deficient in CIRP showed protection from inflammation-associated lung injury. We hypothesize that A 12 inhibits systemic inflammation and ALI in HS. To test the impacts of A 12 on systemic and lung inflammation, extent of inflammatory cellular infiltration and resultant lung damage were evaluated in a mouse model of HS. Male mice were subjected to controlled hemorrhage with a mean arterial pressure of 30 mm Hg for 90 min and then resuscitated with Ringer's lactate solution containing phosphate-buffered saline (vehicle) or A 12 at a dose of 4 nmol/g body weight (treatment). The infusion volume was twice that of the shed blood. At 4 h after resuscitation, mice were euthanized, and blood and lung tissues were harvested. Blood and tissue markers of inflammation and injury were evaluated. Serum markers of injury (lactate dehydrogenase, alanine transaminase, and blood urea nitrogen) and inflammation (TNF-α, IL-6) were increased after HS and A 12 treatment significantly decreased their levels. A 12 treatment also decreased lung levels of TNF-α, MIP-2, and KC mRNA expressions. Lung histological injury score, neutrophil infiltration (Ly6G staining and myeloperoxidase activity), and lung apoptosis were significantly attenuated after A 12 treatment. Our study suggests that the capacity of A 12 in attenuating HS-induced ALI and may provide novel perspectives in developing efficacious pharmaceutics for improving hemorrhage prognosis.

Emergency Department Resuscitative Endovascular Balloon Occlusion of the Aorta in Trauma Patients With Exsanguinating Hemorrhage: The UK-REBOA Randomized Clinical Trial

Importance

Bleeding is the most common cause of preventable death after trauma.

Objective

To determine the effectiveness of resuscitative endovascular balloon occlusion of the aorta (REBOA) when used in the emergency department along with standard care vs standard care alone on mortality in trauma patients with exsanguinating hemorrhage.

Design, Setting, and Participants

Pragmatic, bayesian, randomized clinical trial conducted at 16 major trauma centers in the UK. Patients aged 16 years or older with exsanguinating hemorrhage were enrolled between October 2017 and March 2022 and followed up for 90 days.

Intervention

Patients were randomly assigned (1:1 allocation) to a strategy that included REBOA and standard care (n = 46) or standard care alone (n = 44).

Main Outcomes and Measures

The primary outcome was all-cause mortality at 90 days. Ten secondary outcomes included mortality at 6 months, while in the hospital, and within 24 hours, 6 hours, or 3 hours; the need for definitive hemorrhage control procedures; time to commencement of definitive hemorrhage control procedures; complications; length of stay; blood product use; and cause of death.

Results

Of the 90 patients (median age, 41 years [IQR, 31-59 years]; 62 [69%] were male; and the median Injury Severity Score was 41 [IQR, 29-50]) randomized, 89 were included in the primary outcome analysis because 1 patient in the standard care alone group declined to provide consent for continued participation and data collection 4 days after enrollment. At 90 days, 25 of 46 patients (54%) had experienced all-cause mortality in the REBOA and standard care group vs 18 of 43 patients (42%) in the standard care alone group (odds ratio [OR], 1.58 [95% credible interval, 0.72-3.52]; posterior probability of an OR >1 [indicating increased odds of death with REBOA], 86.9%). Among the 10 secondary outcomes, the ORs for mortality and the posterior probabilities of an OR greater than 1 for 6-month, in-hospital, and 24-, 6-, or 3-hour mortality were all increased in the REBOA and standard care group, and the ORs were increased with earlier mortality end points. There were more deaths due to bleeding in the REBOA and standard care group (8 of 25 patients [32%]) than in standard care alone group (3 of 18 patients [17%]), and most occurred within 24 hours.

Conclusions and Relevance

In trauma patients with exsanguinating hemorrhage, a strategy of REBOA and standard care in the emergency department does not reduce, and may increase, mortality compared with standard care alone.

Trial Registration

isrctn.org Identifier: ISRCTN16184981.

The AccuFlow sensor: a novel digital health tool to assess intrapartum blood loss at cesarean delivery

OBJECTIVES

During obstetric hemorrhage, peripheral vasoconstriction maintains heart rate and blood pressure until compensatory mechanisms are overwhelmed and patients deteriorate rapidly. Real-time perfusion measurements could quantify vasoconstriction, improving early recognition of hemorrhage and facilitating early intervention to reduce morbidity and mortality. The AccuFlow device makes rapid, non-invasive, quantitative measurements of perfusion, but has not been studied for hemorrhage detection or used in surgical settings. This study evaluated feasibility, tolerability, and preliminary efficacy of the AccuFlow for assessment of blood loss at cesarean delivery (CD).

METHODS

In this pilot study, sensors were applied to the wrist, forearm, bicep, and chest wall of 25 patients undergoing scheduled CD. Postoperatively, sensors were removed and patients rated the AccuFlow and the standard anesthesia monitoring equipment on a validated comfort rating scale for wearable computers (CRS). Blood loss was estimated by the surgical team (EBL) and calculated from change in hematocrit, weight, and height (CBL). CRS scores were compared via Wilcoxon signed ranks tests. Coefficients of correlation between sensor readings and CBL, and between EBL and CBL, were compared using Fisher's R-to-z transformation.

RESULTS

There were no safety events; no participants requested device removal. CRS ratings of the AccuFlow and the standard monitoring equipment were similar (7.2 vs. 8.8, p=0.25). Change in wrist perfusion from delivery to dressing placement was more strongly correlated with CBL than was EBL (R=-0.48 vs. R=0.087, p=0.03).

CONCLUSIONS

The AccuFlow sensor is well-tolerated and shows promise in detecting intrapartum hemorrhage, though larger studies are needed.

Interleukin-17 as a spatiotemporal bridge from acute to chronic inflammation: Novel insights from computational modeling

A systematic review of several acute inflammatory diseases ranging from sepsis and trauma/hemorrhagic shock to the relevant pathology of the decade, COVID-19, points to the cytokine interleukin (IL)-17A as being centrally involved in the propagation of inflammation. We summarize the role of IL-17A in acute inflammation, leveraging insights made possible by biological network analysis and novel computational methodologies aimed at defining the spatiotemporal spread of inflammation in both experimental animal models and humans. These studies implicate IL-17A in the cross-tissue spread of inflammation, a process that appears to be in part regulated through neural mechanisms. Although acute inflammatory diseases are currently considered distinct from chronic inflammatory pathologies, we suggest that chronic inflammation may represent repeated, cyclical episodes of acute inflammation driven by mechanisms involving IL-17A. Thus, insights from computational modeling of acute inflammatory diseases may improve diagnosis and treatment of chronic inflammation; in turn, therapeutics developed for chronic/autoimmune disease may be of benefit in acute inflammation. This article is categorized under: Immune System Diseases > Computational Models.

Association Between Profound Shock Signs and Peripheral Intravenous Access Success Rates in Trauma Patients in the Prehospital Scenario: A Retrospective Study

BACKGROUND

Hemorrhage is the leading cause of preventable death in trauma patients, and establishment of intravenous (IV) access is essential for volume resuscitation, a key component in the treatment of hemorrhagic shock. IV access among patients in shock is generally considered more challenging, although data to support this notion are lacking.

METHODS

In this retrospective registry-based study, data were collected from the Israeli Defense Forces Trauma Registry (IDF-TR) regarding all prehospital trauma patients treated by IDF medical forces between January 2020 and April 2022, for whom IV access was attempted. Patients younger than 16 years, nonurgent patients, and patients with no detectable heart rate or blood pressure were excluded. Profound shock was defined as a heart rate >130 or a systolic blood pressure <90 mm Hg, and comparisons were made between patients with profound shock and those not exhibiting such signs. The primary outcome was the number of attempts required for first IV access success, which was regarded as an ordinal categorical variable: 1, 2, 3 and higher and ultimate failure. A multivariable ordinal logistic regression was performed to adjust for potential confounders. Patients' sex, age, mechanism of injury and best consciousness level, as well as type of event (military/nonmilitary), and the presence of multiple patients were included in the ordinal logistic regression multivariable analysis model based on previous publications.

RESULTS

Five hundred thirty-seven patients were included, 15.7% of whom were recorded as having signs of profound shock. Peripheral IV access establishment first attempt success rates were higher in the nonshock group, and there was a lower rate of unsuccessful attempts in this group (80.8% vs 67.8% for the first attempt, 9.4% vs 16.7% for the second attempt, 3.8% vs 5.6% for the third and further attempts, and 6% vs 10% unsuccessful attempts, P = .04). In the univariable analysis, profound shock was associated with requirement for an increased number of IV attempts (odds ratio [OR], 1.94; confidence interval [CI], 1.17-3.15). The ordinal logistic regression multivariable analysis demonstrated that profound shock was associated with worse results regarding primary outcome (adjusted odds ratio [AOR], 1.84; CI, 1.07-3.10).

CONCLUSIONS

The presence of profound shock in trauma patients in the prehospital scenario is associated with an increased number of attempts required for IV access establishment.

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.

Emerging technology for early detection and management of postpartum hemorrhage to prevent morbidity

Despite advances in hemorrhage detection and management, postpartum hemorrhage remains the single leading cause of maternal death worldwide. Within the United States, hemorrhage is the leading cause of maternal death on the day of delivery and within the first week after delivery. Blood transfusion after hemorrhage represents a large proportion of severe maternal morbidity during and after delivery. Blood loss during delivery has historically been assessed visually by inspecting soiled pads, linens, and laparotomy sponges. These methods underestimate the volume of blood loss by as much as 40%, becoming increasingly inaccurate as blood loss increases. Young, healthy obstetrical patients compensate for blood loss via peripheral vasoconstriction, maintaining heart rate and blood pressure in a normal range until over 1 L of blood has been lost. A significant decrease in blood pressure along with marked tachycardia (>120 bpm) may not be seen until 30% to 40% of blood volume has been lost, or 2.0 to 2.6 L in a healthy term pregnant patient, after which the patient may rapidly decompensate. In resource-poor settings especially, the narrow window between the emergence of significant vital sign abnormalities and clinical decompensation may prove catastrophic. Once hemorrhage is detected, decisions regarding blood product transfusion are routinely made on the basis of inaccurate estimates of blood loss, placing patients at risk of underresuscitation (increasing the risk of hemorrhagic shock and end-organ damage) or overresuscitation (increasing the risk of transfusion reaction, fluid overload, and alloimmunization). We will review novel technologies that have emerged to assist both in the early and accurate detection of postpartum hemorrhage and in decisions regarding blood product transfusion.

Effects of extremity trauma on physiological responses to hemorrhage in conscious rats

Although physiological responses to hemorrhage are well-studied, hemorrhage is often accompanied by trauma, and it remains unclear how injury affects these responses. This study examined effects of extremity trauma on cardiorespiratory responses and survival to moderate (37%; H-37) or severe (50%; H-50) hemorrhage in rats. Transmitter and carotid catheter implantation and extremity trauma (fibular fracture and muscle injury) were conducted 2 wk, 24 h, and 90 min, respectively, before conscious hemorrhage. Mean arterial pressure (MAP) and heart rate (HR; via telemetry), and respiration rate (RR), minute volume (MV), and tidal volume (TV; via plethysmography) were measured throughout the 25 min hemorrhage and remainder of the 4 h observation period. There were four groups: 1) H-37, no trauma (NT; n = 17); 2) H-37, extremity trauma (T, n = 18); 3) H-50, NT (n = 20); and 4) H-50, T (n = 20). For H-37, during and after hemorrhage, T increased HR (P ≤ 0.031) and MV (P ≤ 0.048) compared with NT rats. During H-50, T increased HR (0.041) and MV (P = 0.043). After hemorrhage, T increased MV (P = 0.008) but decreased HR (P = 0.007) and MAP (P = 0.039). All cardiorespiratory differences between T and NT groups were intermittent. Importantly, both survival time (159.8 ± 78.2 min vs. 211.9 ± 60.3 min; P = 0.022; mean ± SD) and percent survival (45% vs. 80%; P = 0.048) were less in T versus NT rats after H-50. Trauma interacts with physiological systems in a complex manner and no single cardiorespiratory measure was sufficiently altered to indicate that it alone could account for increased mortality after H-50.NEW & NOTEWORTHY In both civilian and military settings, severe hemorrhage rarely occurs in the absence of tissue trauma, yet many animal models for the study of hemorrhage do not include significant tissue trauma. This study using conscious unrestrained rats clearly demonstrates that extremity trauma worsens the probability of survival after a severe hemorrhage. Although no single cardiorespiratory factor accounted for the increased mortality, multiple modest time-related cardiorespiratory responses to the trauma were observed suggesting that their combined dysfunction may have contributed to the reduced survival.

Mitochondrial antioxidant SkQ1 decreases inflammation following hemorrhagic shock by protecting myocardial mitochondria

Background: Hemorrhagic shock (HS) is a type of hypovolemic shock characterized by hemodynamic instability, tissue hypoperfusion and cellular hypoxia. In pathophysiology, the gradual accumulation of reactive oxygen species (ROS) damages the mitochondria, leading to irreversible cell damage and the release of endogenous damage-associated molecular patterns (DAMPs) including mitochondrial DAMPs (MTDs), eventually triggering the inflammatory response. The novel mitochondria-targeted antioxidant SkQ1 (Visomitin) effectively eliminate excessive intracellular ROS and exhibits anti-inflammatory effects; however, the specific role of SkQ1 in HS has not yet been explicated. Methods and results: A 40% fixed-blood-loss HS rat model was established in this study. Transmission electron microscopy showed that after HS, the myocardial mitochondrial ultrastructure was damaged and the mtDNA release in circulation was increased and the differentially expressed genes were significantly enriched in mitochondrial and ROS-related pathways. Mitochondria-targeted antioxidant SkQ1 attenuated the increased ROS induced by HS in myocardial tissues and by oxygen-glucose deprivation (OGD) in cardiomyocytes. Ultrastructurally, SkQ1 protected the myocardial mitochondrial structure and reduced the release of the peripheral blood mtDNA after HS. RNA-seq transcriptome analysis showed that 56.5% of the inflammation-related genes, which altered after HS, could be significantly reversed after SkQ1 treatment. Moreover, ELISA indicated that SkQ1 significantly reversed the HS-induced increases in the TNF-α, IL-6, and MCP-1 protein levels in rat peripheral blood. Conclusion: HS causes damage to the rat myocardial mitochondrial structure, increases mtDNA release and ROS contents, activates the mitochondrial and ROS-related pathways, and induces systemic inflammatory response. The mitochondrial antioxidant SkQ1 can improve rat myocardial mitochondria ultrastructure, reduce mtDNA and ROS contents, and decrease inflammation by protecting myocardial mitochondria, thereby playing a novel protective role in HS.

Inferring Tissue-Specific, TLR4-Dependent Type 17 Immune Interactions in Experimental Trauma/Hemorrhagic Shock and Resuscitation Using Computational Modeling

Trauma/hemorrhagic shock followed by resuscitation (T/HS-R) results in multi-system inflammation and organ dysfunction, in part driven by binding of damage-associated molecular pattern molecules to Toll-like Receptor 4 (TLR4). We carried out experimental T/HS-R (pseudo-fracture plus 2 h of shock followed by 0-22 h of resuscitation) in C57BL/6 (wild type [WT]) and TLR4-null (TLR4^-/-) mice, and then defined the dynamics of 20 protein-level inflammatory mediators in the heart, gut, lung, liver, spleen, kidney, and systemic circulation. Cross-correlation and Principal Component Analysis (PCA) on data from the 7 tissues sampled suggested that TLR4^-/- samples express multiple inflammatory mediators in a small subset of tissue compartments as compared to the WT samples, in which many inflammatory mediators were localized non-specifically to nearly all compartments. We and others have previously defined a central role for type 17 immune cells in human trauma. Accordingly, correlations between IL-17A and GM-CSF (indicative of pathogenic Th17 cells); between IL-17A and IL-10 (indicative of non-pathogenic Th17 cells); and IL-17A and TNF (indicative of memory/effector T cells) were assessed across all tissues studied. In both WT and TLR4^-/- mice, positive correlations were observed between IL-17A and GM-CSF, IL-10, and TNF in the kidney and gut. In contrast, the variable and dynamic presence of both pathogenic and non-pathogenic Th17 cells was inferred in the systemic circulation of TLR4^-/- mice over time, suggesting a role for TLR4 in efflux of these cells into peripheral tissues. Hypergraph analysis - used to define dynamic, cross compartment networks - in concert with PCA-suggested that IL-17A was present persistently in all tissues at all sampled time points except for its absence in the plasma at 0.5h in the WT group, supporting the hypothesis that T/HS-R induces efflux of Th17 cells from the circulation and into specific tissues. These analyses suggest a complex, context-specific role for TLR4 and type 17 immunity following T/HS-R.

The effectiveness and cost-effectiveness of resuscitative endovascular balloon occlusion of the aorta (REBOA) for trauma patients with uncontrolled torso haemorrhage: study protocol for a randomised clinical trial (the UK-REBOA trial)

BACKGROUND

Haemorrhage is the most common cause of preventable death after injury. REBOA is a novel technique whereby a percutaneously inserted balloon is deployed in the aorta, providing a relatively quick means of temporarily controlling haemorrhage and augmenting cerebral and coronary perfusion, until definitive control of haemorrhage can be attained. The aim of the UK-REBOA trial is to establish the clinical and cost-effectiveness of a policy of standard major trauma centre treatment plus REBOA, as compared with standard major trauma centre treatment alone, for the management of uncontrolled torso haemorrhage caused by injury.

METHODS

Pragmatic, Bayesian, group-sequential, randomised controlled trial, performed in 16 major trauma centres in England. We aim to randomise 120 injured patients with suspected exsanguinating haemorrhage to either standard major trauma centre care plus REBOA or standard major trauma centre care alone. The primary clinical outcome is 90-day mortality. Secondary clinical outcomes include 3-h, 6-h, and 24-h mortality; in-hospital mortality; 6-month mortality; length of stay (in hospital and intensive care unit); 24-h blood product use; need for haemorrhage control procedure (operation or angioembolisation); and time to commencement of haemorrhage control procedure (REBOA, operation, or angioembolisation). The primary economic outcome is lifetime incremental cost per QALY gained, from a health and personal social services perspective.

DISCUSSION

This study, which is the first to randomly allocate patients to treatment with REBOA or standard care, will contribute high-level evidence on the clinical and cost-effectiveness of REBOA in the management of trauma patients with exsanguinating haemorrhage and will provide important data on the feasibility of implementation of REBOA into mainstream clinical practice.

TRIAL REGISTRATION

ISRCTN16184981.

Tyrosine kinase nonreceptor 1 (TNK1) knockdown ameliorates hemorrhage shock-induced kidney injury via inhibiting macrophage M1 polarization

Hemorrhage shock (HS) is a major threat to patients with trauma and spontaneous bleeding, resulting in multi-organ failure including the kidney. Tyrosine kinase nonreceptor 1 (TNK1) has been shown to be upregulated in the kidney of experimental HS and patients with severe trauma. The study aims to investigate the role of TNK1 and the underlying mechanism in HS-induced kidney injury. A model of HS was established with femoral artery bloodletting, followed by resuscitation in Sprague-Dawley rats. Renal expression of TNK1 was abnormally induced by HS in rats. Knockdown of TNK1 alleviated HS-induced cell apoptosis and the level of proinflammatory cytokines (TNF-α, IL-6 and IL-1β) in the kidney. The expression of M1 macrophage markers (CD86 and iNOS) and the activation of STAT1 were inhibited by TNK1 knockdown in HS rats. In vitro, human monocyte THP-1 cells were treated with 20 ng/mL interferon-gamma plus 100 ng/mL lipopolysaccharide to induce M1 polarization. TNK1 knockdown exerted inhibitory effect on macrophage M1 polarization, M1-type inflammatory cytokine production and STAT1 activation in THP-1 cells. In conclusion, downregulation of TNK1 alleviates HS-induced kidney injury by suppressing macrophage M1 polarization, inflammation and kidney cell apoptosis, in which the deactivation of STAT1 signaling may be involved.

CD226 deficiency promotes glutaminolysis and alleviates mitochondria damage in vascular endothelial cells under hemorrhagic shock

Hemorrhagic shock (HS) is common in clinical emergencies, leading to millions of deaths each year globally. CD226 is a costimulatory adhesion molecule expressed on both immune cells and endothelial cells (ECs) to regulate their metabolic activity and function. As endothelial dysfunction occurs after HS, the roles CD226 plays in vascular EC metabolism were investigated. CD226^fl/fl Tek^cre mice were adopted to achieve vascular EC-specific knockout of CD226, and subjected to HS modelling. Serum levels of crucial intermediate metabolites were evaluated through liquid chromatography-mass spectrometry analysis. Human umbilical vein ECs (HUVECs) were used to study the effects of CD226 under hypoxia in vitro. Seahorse analysis evaluated the cellular glycolysis and mitochondria bioenergetics. Results showed that CD226 deficiency in vascular ECs alleviated HS-induced intestinal damage and inflammatory response in mice. Animal studies indicated an improved energy metabolism when CD226 was knocked out in ECs after HS, as evidenced by enhanced glutamine-glutamate metabolism and decreased lactic acid levels. Glut-1 was upregulated in mouse vascular ECs after HS and HUVECs under hypoxia, combined with decreased CD226. Moreover, HUVECs with CD226 knockdown exhibited relieved mitochondrial damage and early apoptosis under hypoxia, whereas CD226 overexpression showed opposite effects. Seahorse analysis showed that downregulated CD226 significantly increased mitochondrial ATP production and glucose uptake in HUVECs under hypoxia. Additionally, Erk/PHD2 signaling-mediated HIF-1α/Glut-1 and HIF-2α/ASCT2 pathways were involved in CD226 regulation on HUVEC glutaminolysis after hypoxia. Hence, CD226 deficiency promotes bypass energy supply to vascular ECs under ischemic or hypoxic stress, to ameliorate the stress-mediated metabolic disturbance.

Cardiovascular Effects Mediated by HMMR and CD44

Cardiovascular disease (CVD) is the leading cause of death worldwide. The most dangerous life-threatening symptoms of CVD are myocardial infarction and stroke. The causes of CVD are not entirely clear, and new therapeutic targets are still being sought. One of the factors involved in CVD development among vascular damage and oxidative stress is chronic inflammation. It is known that hyaluronic acid plays an important role in inflammation and is regulated by numerous stimuli, including proinflammatory cytokines. The main receptors for hyaluronic acid are CD44 and RHAMM. These receptors are membrane proteins that differ in structure, but it seems that they can perform similar or synergistic functions in many diseases. Both RHAMM and CD44 are involved in cell migration and wound healing. However, their close association with CVD is not fully understood. In this review, we describe the role of both receptors in CVD.

Transfusion of Anaerobically or Conventionally Stored Blood After Hemorrhagic Shock

Background:

Resuscitation from hemorrhagic shock (HS) by blood transfusion restores oxygen (O₂) delivery and provides hemodynamic stability. Current regulations allow red blood cells (RBCs) to be stored and used for up to 42 days. During storage, RBCs undergo many structural and functional changes. These storage lesions have been associated with adverse events and increased mortality after transfusion, increasing the need for improved RBC storage protocols. This study evaluates the efficacy of anaerobically stored RBCs to resuscitate rats from severe HS compared with conventionally stored RBCs.

Methods and results:

Rat RBCs were stored under anaerobic, anaerobic/hypercapnic, or conventional conditions for a period of 3 weeks. Hemorrhage was induced by controlled bleeding, shock was maintained for 30 min, and RBCs were transfused to restore and maintain blood pressure near the prhemorrhage level. All storage conditions met current regulatory 24-h posttransfusion recovery requirements. Transfusion of anaerobically stored RBCs required significantly less RBC volume to restore and maintain hemodynamics. Anaerobic or anaerobic/hypercapnic RBCs restored hemodynamics better than conventionally stored RBCs. Resuscitation with conventionally stored RBCs impaired indices of left ventricular cardiac function, increased hypoxic tissue staining and inflammatory markers, and affected organ function compared with anaerobically stored RBCs.

Conclusions:

Resuscitation from HS via transfusion of anaerobically stored RBCs recovered cardiac function, restored hemodynamic stability, and improved outcomes.

Zone-dependent acute circulatory changes in abdominal organs and extremities after resuscitative balloon occlusion of the aorta (REBOA): an experimental model

INTRODUCTION

Resuscitative endovascular balloon occlusion of the aorta (REBOA) may be used in severely injured patients with uncontrollable bleeding. However, zone-dependent effects of REBOA are rarely described. We compared the short-term zone- and organ-specific microcirculatory changes in abdominal organs and the extremity during occlusion of the aorta in a standardized porcine model.

METHODS

Male pigs were placed under general anesthesia, for median laparotomy to expose intra-abdominal organs. REBOA placement occurred in Zone 1 (from origin left subclavian artery to celiac trunk), Zone 2 (between the coeliac trunk and most caudal renal artery) and Zone 3 (distal most caudal renal artery to aortic bifurcation). Local microcirculation of the intra-abdominal organs were measured at the stomach, colon, small intestine, liver, and kidneys. Furthermore, the right medial vastus muscle was included for assessment. Microcirculation was measured using oxygen-to-see device (arbitrary units, A.U). Invasive blood pressure measurements were recorded in the carotid and femoral artery (ipsilateral). Ischemia/Reperfusion (I/R)-time was 10 min with complete occlusion.

RESULTS

At baseline, microcirculation of intra-abdominal organs differed significantly (p < 0.001), the highest flow was in the kidneys (208.3 ± 32.9 A.U), followed by the colon (205.7 ± 36.2 A.U.). At occlusion in Zone 1, all truncal organs showed significant decreases (p < 0.001) in microcirculation, by 75% at the colon, and 44% at the stomach. Flow-rate changes at the extremities were non-significant (n.s). During occlusion in Zone 2, a significant decrease (p < 0.001) in microcirculation was observed at the colon (- 78%), small intestine (- 53%) and kidney (- 65%). The microcirculatory changes at the extremity were n.s. During occlusion in Zone 3, truncal and extremity microcirculatory changes were n.s.

CONCLUSION

All abdominal organs showed significant changes in microcirculation during REBOA. The intra-abdominal organs react differently to the same occlusion, whereas local microcirculation in extremities appeared to be unaffected by short-time REBOA, regardless of the zone of occlusion.

Longevity pathways in stress resistance: targeting NAD and sirtuins to treat the pathophysiology of hemorrhagic shock

Stress resistance correlates with longevity and this pattern has been exploited to help identify genes that can influence lifespan. Reciprocally, genes and pharmacological agents that have been studied primarily in the context of longevity may be an untapped resource for treating acute stresses. Here we summarize the evidence that targeting SIRT1, studied primarily in the context of longevity, can improve outcomes in hemorrhagic shock and resuscitation. Hemorrhagic shock is a potentially fatal condition that occurs when blood loss is so severe that tissues no longer receive adequate oxygen. While stabilizing the blood pressure and reperfusing tissues are necessary, re-introducing oxygen to ischemic tissues generates a burst of reactive oxygen species that can cause secondary tissue damage. Reactive oxygen species not only exacerbate the inflammatory cascade but also can directly damage mitochondria, leading to bioenergetic failure in the affected tissues. Treatments with polyphenol resveratrol and with nicotinamide adenine dinucleotide (NAD) precursors have both shown promising results in rodent models of hemorrhagic shock and resuscitation. Although a number of different mechanisms may be at play in each case, a common theme is that resveratrol and NAD both enhance the activity of SIRT1. Moreover, many of the physiologic improvements observed with resveratrol and NAD precursors are consistent with modulation of known SIRT1 targets. Because small blood vessels and limited blood volume make mice very challenging for the development of hemorrhagic shock models, there is a paucity of direct genetic evidence testing the role of SIRT1. However, the development of more robust methods in mice as well as genetic modifications in rats should allow the study of SIRT1 transgenic and KO rodents in the near future. The potential therapeutic effect of SIRT1 in hemorrhagic shock may serve as an important example supporting the value of considering "longevity" pathways in the mitigation of acute stresses.

The venous contribution to cardiovascular performance: From systemic veins to left ventricular function: A review

The venous system contains ≈ 70 % of the total blood volume and is responsible in heart failure for key symptoms of congestion. It is active: it can increase or relax its tone with physiologic or pharmacologic stimuli. It is heterogeneous, behaves as a two-compartment model, compliant (splanchnic veins) and noncompliant (nonsplanchnic veins). It is dynamic in health and disease: in heart failure the vascular capacitance (storage space) is decreased and can result in volume redistribution from the abdominal compartment to the thoracic compartment (heart and lungs), which increases pulmonary pressures and precipitates pulmonary congestion. A noninvasive assessment of venous function, at rest and dynamically during stress, is warranted. The systemic haemodynamic congestion is assessed with inferior vena cava diameter and collapsibility. The pulmonary congestion is assessed with B-lines and pleural effusion. The contribution of left ventricular filling is assessed with end-diastolic volume, integrated with left ventricular function.

Efficacy of Different Fluid Resuscitation Methods on Coagulation Function of Rats with Traumatic Hemorrhagic Shock

BACKGROUND

Fluid resuscitation is widely used for treating traumatic hemorrhagic shock. We focused on the efficacies of different fluid resuscitation methods on improving coagulation function of traumatic hemorrhagic shock (THS) rats.

MATERIALS AND METHODS

Sprague-Dawley rats (n = 100) were randomly divided into 5 groups, namely, Sham group, THS group, acetic acid Ringer's fluid (AR) group, hydroxyethyl starch solution (HES) group, and AR + HES group. A THS rat model was established by left femoral bleeding. The effects of different fluid resuscitation methods on conventional coagulation function parameters, Rotational thromboelastometry parameters, platelet-derived microparticles and endothelial cell-derived microparticles content of the THS rats were detected by ACL TOP system, rotation thromboelastometry, and flow cytometry, respectively.

RESULTS

Using AR and HES alone had no significant effect on the coagulation function of THS rats, but the two in combination reduced the increases of thrombin time, prothrombin time, activated part thrombin time, international normalized ratio, fibrin degradation products, D-dimer and the decreases of platelet count and fibrinogen concentration induced by THS. The CT and CFT were significantly reduced, whereas α and MCF were increased in the THS rats in AR + HES group. The combination of AR and HES reversed the effect of THS on elevating platelet-derived microparticles and endothelial cell-derived microparticle levels. In addition, the coagulation was relatively the optimal in the AR, HES, and AR + HES groups when the mice were resuscitated to a mean arterial pressure of 60 mmHg.

CONCLUSIONS

AR combined with HES has a significant protective effect on coagulation function of THS rats when the mean arterial pressure reaches 60 mmHg.

Quantitative Assessment of Blood Lactate in Shock: Measure of Hypoxia or Beneficial Energy Source

Blood lactate concentration predicts mortality in critically ill patients and is clinically used in the diagnosis, grading of severity, and monitoring response to therapy of septic shock. This paper summarizes available quantitative data to provide the first comprehensive description and critique of the accepted concepts of the physiology of lactate in health and shock, with particular emphasis on the controversy of whether lactate release is simply a manifestation of tissue hypoxia versus a purposeful transfer ("shuttle") of lactate between tissues. Basic issues discussed include (1) effect of nonproductive lactate-pyruvate exchange that artifactually enhances flux measurements obtained with labeled lactate, (2) heterogeneous tissue oxygen partial pressure (Krogh model) and potential for unrecognized hypoxia that exists in all tissues, and (3) pathophysiology that distinguishes septic from other forms of shock. Our analysis suggests that due to exchange artifacts, the turnover rate of lactate and the lactate clearance are only about 60% of the values of 1.05 mmol/min/70 kg and 1.5 L/min/70 kg, respectively, determined from the standard tracer kinetics. Lactate turnover reflects lactate release primarily from muscle, gut, adipose, and erythrocytes and uptake by the liver and kidney, primarily for the purpose of energy production (TCA cycle) while the remainder is used for gluconeogenesis (Cori cycle). The well-studied physiology of exercise-induced hyperlactatemia demonstrates massive release from the contracting muscle accompanied by an increased lactate clearance that may occur in recovering nonexercising muscle as well as the liver. The very limited data on lactate kinetics in shock patients suggests that hyperlactatemia reflects both decreased clearance and increased production, possibly primarily in the gut. Our analysis of available data in health and shock suggests that the conventional concept of tissue hypoxia can account for most blood lactate findings and there is no need to implicate a purposeful production of lactate for export to other organs.

Different Effects of Volatile and Nonvolatile Anesthetic Agents on Long-Term Survival in an Experimental Model of Hemorrhagic Shock

BACKGROUND

We investigated whether the cardioprotective, volatile gas anesthetic agent, isoflurane, could improve survival and organ function from hemorrhagic shock in an experimental rat model, compared to standard nonvolatile anesthetic agent ketamine/xylazine.

METHODS

Sprague Dawley rats (both genders) were randomized to receive either intraperitoneal ketamine/xylazine (K/X, 90 and 10 mg/kg; n = 12) or isoflurane (5% isoflurane induction and 2% maintenance in room air; n = 12) for anesthesia. Blood was withdrawn to maintain mean arterial blood pressure at 30 mm Hg for 1 hour, followed by 30 minutes of resuscitation with shed blood. Rats were allowed to recover and survive for 6 weeks.

RESULTS

During the shock phase, the total withdrawn blood volume (expressed as % of estimated total blood volume) to maintain a level of hypotension of 30 mm Hg was significantly higher in the isoflurane group (51.0% ± 1.5%) than in the K/X group (45.3% ± 1.8%; P = .023). Recovery of blood pressure during the resuscitation phase was significantly improved in the isoflurane group compared to the K/X group. The survival rate at 6 weeks was 1 (8.3%) of 12 in rats receiving K/X and 10 (83.3%) of 12 in rats receiving isoflurane (P < .001). Histology performed at 6 weeks demonstrated brain infarction in the 1 surviving rat receiving K/X; no brain infarction occurred in the 10 surviving rats that received isoflurane. No infarction was detected in heart, lung, liver, or kidneys among the surviving rats.

CONCLUSIONS

Isoflurane improved blood pressure response to resuscitation and resulted in significantly higher long-term survival rate.

Stop the Bleed: gap analysis and geographical evaluation of incident locations

BACKGROUND

Trauma is a major public health issue. In 2015, the White House launched the "Stop the Bleed" (STB) campaign, which aims to equip would-be bystanders with the ability and equipment to assist in bleeding emergencies. This study sought to estimate the number of patients who might benefit from STB intervention, in an everyday setting, and their spatial injury profile.

METHODS

This is a retrospective analysis of trauma registry and medical examiners' data, collected between 2013 and 2017. The majority of patients were male. The median age was 32 years. Incidents were geocoded by ZIP code, and mapped using Quantum Geographic Information System (QGIS).

RESULTS

We identified 139 patients from medical examiner records and UAB's trauma registry who might have benefitted from STB intervention. The number of incidents per year ranged from 22 to 35, averaging 2.3 incidents per month. There was no evidence of geographical clustering, although the small number of incidents precluded a formal geostatistical analysis.

CONCLUSION

The number of patients who might benefit from STB interventions on a daily basis is small, and incident locations are difficult to predict. Educating the public in how to stop bleeding is appealing, but providing easy and widespread access to STB kits may be difficult. Although there are parallels to the provision of cardiopulmonary resuscitation and defibrillation for cardiac arrest, there are also differences, which should not be overlooked.

Methane-Rich Saline: A Potential Resuscitation Fluid for Hemorrhagic Shock

Hemorrhagic shock is caused by massive blood loss. If the patient is not fully resuscitated in time, this may eventually lead to multiple organ failure and even death. Previous studies on methane-rich saline in animal models showed that it confers resistance against many diseases. In this study, we explored the protective effect of methane-rich saline, used as a resuscitation fluid, in hemorrhagic shock. Hemorrhagic shock was induced in SD rats by bloodletting via intubation of the right femoral artery. The rats were divided into three groups: a sham control group (sham control), a shock group resuscitated by an infusion of autologous blood and an equivalent volume of normal saline (Shock+NS), and a shock group resuscitated by an infusion of autologous blood and an equivalent volume of methane-rich saline (Shock+MRS). Assessment of blood pressure and levels of plasma lactate showed that resuscitation using methane-rich saline (MRS) restored systemic blood pressure and reduced the levels of lactate in the plasma. Meanwhile, lower levels of serum IL-6 and TNF-α were also observed in the group resuscitated with MRS. In the heart, liver, and kidney, MRS reduced inflammation and oxidative stress levels. Analysis of organ function via levels of biochemical indicators revealed that the group resuscitated with MRS had reduced serum levels of AST and CK, indicating a potential cardioprotective effect. The expression levels of apoptosis-related proteins, including those of Bcl-2/Bax, and the results of TUNEL-labeling assay indicated that MRS significantly reduced apoptosis in the heart. Methane also had a positive effect on the expression of the PGC-1α/SIRT3/SOD2 signaling pathway. Our results showed that MRS can potentially serve as a novel resuscitation fluid because of its anti-inflammatory, antioxidative, and antiapoptotic properties.

A systematic review of large animal models of combined traumatic brain injury and hemorrhagic shock

Traumatic brain injury (TBI) and severe blood loss (SBL) frequently co-occur in human trauma, resulting in high levels of mortality and morbidity. Importantly, each of the individual post-injury cascades is characterized by complex and potentially opposing pathophysiological responses, complicating optimal resuscitation and therapeutic approaches. Large animal models of poly-neurotrauma closely mimic human physiology, but a systematic literature review of published models has been lacking. The current review suggests a relative paucity of large animal poly-neurotrauma studies (N = 52), with meta-statistics revealing trends for animal species (exclusively swine), characteristics (use of single biological sex, use of juveniles) and TBI models. Although most studies have targeted blood loss volumes of 35-45%, the associated mortality rates are much lower relative to Class III/IV human trauma. This discrepancy may result from potentially mitigating experimental factors (e.g., mechanical ventilation prior to or during injury, pausing/resuming blood loss based on physiological parameters, administration of small volume fluid resuscitation) that are rarely associated with human trauma, highlighting the need for additional work in this area.

Computational evidence for an early, amplified systemic inflammation program in polytrauma patients with severe extremity injuries

Extremity and soft tissue injuries contribute significantly to inflammation and adverse in-hospital outcomes for trauma survivors; accordingly, we examined the complex association between clinical outcomes inflammatory responses in this setting using in silico tools. Two stringently propensity-matched, moderately/severely injured (Injury Severity Score > 16) patient sub-cohorts of ~30 patients each were derived retrospectively from a cohort of 472 blunt trauma survivors and segregated based on their degree of extremity injury severity (above or below 3 on the Abbreviated Injury Scale). Serial blood samples were analyzed for 31 plasma inflammatory mediators. In addition to standard statistical analyses, Dynamic Network Analysis (DyNA) and Principal Component Analysis (PCA) were used to model systemic inflammation following trauma. Patients in the severe extremity injury sub-cohort experienced longer intensive care unit length of stay (LOS), total LOS, and days on a mechanical ventilator, with higher Marshall Multiple Organ Dysfunction (MOD) Scores over the first 7 days post-injury as compared to the mild/moderate extremity injury sub-cohort. The higher severity cohort had statistically significant elevated lactate, base deficit, and creatine phosphokinase on first blood draw, along with significant changes in multiple circulating inflammatory mediators. DyNA pointed to a sustained role for type 17 immunity in both sub-cohorts, along with IFN-γ in the severe extremity injury group. DyNA network complexity increased over 7 days post-injury in the severe injury group, while generally decreasing over this same time period in the mild/moderate injury group. PCA suggested a more robust activation of multiple pathways in the severe extremity injury group as compared to the mild/moderate injury group. These studies thus point to the possibility of self-sustaining inflammation following severe extremity injury vs. resolving inflammation following less severe extremity injury.

Trigeminal Nerve Stimulation: A Novel Method of Resuscitation for Hemorrhagic Shock

OBJECTIVES

To determine if trigeminal nerve stimulation can ameliorate the consequences of acute blood loss and improve survival after severe hemorrhagic shock.

DESIGN

Animal study.

SETTING

University research laboratory.

SUBJECTS

Male Sprague-Dawley rats.

INTERVENTIONS

Severe hemorrhagic shock was induced in rats by withdrawing blood until the mean arterial blood pressure reached 27 ± 1 mm Hg for the first 5 minutes and then maintained at 27 ± 2 mm Hg for 30 minutes. The rats were randomly assigned to either control, vehicle, or trigeminal nerve stimulation treatment groups. The effects of trigeminal nerve stimulation on survival rate, autonomic nervous system activity, hemodynamics, brain perfusion, catecholamine release, and systemic inflammation after severe hemorrhagic shock in the absence of fluid resuscitation were analyzed.

MEASUREMENTS AND MAIN RESULTS

Trigeminal nerve stimulation significantly increased the short-term survival of rats following severe hemorrhagic shock in the absence of fluid resuscitation. The survival rate at 60 minutes was 90% in trigeminal nerve stimulation treatment group whereas 0% in control group (p < 0.001). Trigeminal nerve stimulation elicited strong synergistic coactivation of the sympathetic and parasympathetic nervous system as measured by heart rate variability. Without volume expansion with fluid resuscitation, trigeminal nerve stimulation significantly attenuated sympathetic hyperactivity paralleled by increase in parasympathetic tone, delayed hemodynamic decompensation, and improved brain perfusion following severe hemorrhagic shock. Furthermore, trigeminal nerve stimulation generated sympathetically mediated low-frequency oscillatory patterns of systemic blood pressure associated with an increased tolerance to central hypovolemia and increased levels of circulating norepinephrine levels. Trigeminal nerve stimulation also decreased systemic inflammation compared with the vehicle.

CONCLUSIONS

Trigeminal nerve stimulation was explored as a novel resuscitation strategy in an animal model of hemorrhagic shock. The results of this study showed that the stimulation of trigeminal nerve modulates both sympathetic and parasympathetic nervous system activity to activate an endogenous pressor response, improve cerebral perfusion, and decrease inflammation, thereby improving survival.

Improved Long-term Survival with Remote Limb Ischemic Preconditioning in a Rat Fixed-Pressure Hemorrhagic Shock Model

PURPOSE

We investigated whether bilateral, lower limb remote ischemic preconditioning (RIPC) improved long-term survival using a rat model of hemorrhagic shock/resuscitation.

METHODS

Rats were anesthetized, intubated and ventilated, and randomly assigned to RIPC, induced by inflating bilateral pressure cuffs around the femoral arteries to 200 mmHg for 5 min, followed by 5-min release of the cuffs (repeated for 4 cycles), or control group (cuffs were inflated to 30 mmHg). Hemorrhagic shock was induced by withdrawing blood to a fixed mean blood pressure of 30 mmHg for 30 min, followed by 30 min of resuscitation with shed blood. Rats remained anesthetized for 1 h during which hemodynamics were monitored then they were allowed to survive for 6 weeks.

RESULTS

The percentage of estimated total blood volume withdrawn to maintain a level of 30 mmHg was similar in both groups. RIPC significantly increased survival at 6 weeks: 5 of 27 (19%) rats in the control group and 13 of 26 (50%; p = 0.02) rats in the RIPC group survived. Blood pressure was higher in the RIPC group. The diastolic internal dimension of the left ventricle, an indicator of circulating intravascular blood volume, was significantly larger in the RIPC group at 1 h after initiation of resuscitation compared to the control group (p = 0.04). Left ventricular function assessed by fractional shortening was comparable in both groups at 1 h after initiation of resuscitation. Blood urea nitrogen (BUN) was within normal range in the RIPC group (17.3 ± 1.2 mg/dl) but elevated in the control group (22.0 ± 1.7 mg/dl) at 48 h after shock.

CONCLUSIONS

RIPC significantly improved short-term survival in rats that were subjected to hemorrhagic shock, and this benefit was maintained long term. RIPC led to greater circulating intravascular blood volume in the early phase of resuscitation and improved BUN.

Nicotinamide mononucleotide preserves mitochondrial function and increases survival in hemorrhagic shock

Hemorrhagic shock depletes nicotinamide adenine dinucleotide (NAD) and causes metabolic derangements that, in severe cases, cannot be overcome, even after restoration of blood volume and pressure. However, current strategies to treat acute blood loss do not target cellular metabolism. We hypothesized that supplemental nicotinamide mononucleotide (NMN), the immediate biosynthetic precursor to NAD, would support cellular energetics and enhance physiologic resilience to hemorrhagic shock. In a rodent model of decompensated hemorrhagic shock, rats receiving NMN displayed significantly reduced lactic acidosis and serum IL-6 levels, two strong predictors of mortality in human patients. In both livers and kidneys, NMN increased NAD levels and prevented mitochondrial dysfunction. Moreover, NMN preserved mitochondrial function in isolated hepatocytes cocultured with proinflammatory cytokines, indicating a cell-autonomous protective effect that is independent from the reduction in circulating IL-6. In kidneys, but not in livers, NMN was sufficient to prevent ATP loss following shock and resuscitation. Overall, NMN increased the time animals could sustain severe shock before requiring resuscitation by nearly 25% and significantly improved survival after resuscitation (P = 0.018), whether NMN was given as a pretreatment or only as an adjunct during resuscitation. Thus, we demonstrate that NMN substantially mitigates inflammation, improves cellular metabolism, and promotes survival following hemorrhagic shock.

A systematic review and meta-analysis of the use of resuscitative endovascular balloon occlusion of the aorta in the management of major exsanguination

BACKGROUND

Circulatory collapse is a leading cause of mortality among traumatic major exsanguination and in ruptured aortic aneurysm patients. Approximately 40% of patients die before hemorrhage control is achieved. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an adjunct designed to sustain the circulation until definitive surgical or endovascular repair. A systematic review was conducted for the current clinical use of REBOA in patients with hemodynamic instability and to discuss its potential role in improving prehospital and in-hospital outcome.

METHODS

Systematic review and meta-analysis (1900-2017) using MEDLINE, Cochrane, EMBASE, Web of Science and Central and Emcare using the keywords "aortic balloon occlusion", "aortic balloon tamponade", "REBOA", and "Resuscitative Endovascular Balloon Occlusion" in combination with hemorrhage control, hemorrhage, resuscitation, shock, ruptured abdominal or thoracic aorta, endovascular repair, and open repair. Original published studies on human subjects were considered.

RESULTS

A total of 490 studies were identified; 89 met criteria for inclusion. Of the 1436 patients, overall reported mortality was 49.2% (613/1246) with significant differences (p < 0.001) between clinical indications. Hemodynamic shock was evident in 79.3%, values between clinical indications showed significant difference (p < 0.001). REBOA was favored as treatment in trauma patients in terms of mortality. Pooled analysis demonstrated an increase in mean systolic pressure by almost 50 mmHg following REBOA use.

CONCLUSION

REBOA has been used in trauma patients and ruptured aortic aneurysm patients with improvement of hemodynamic parameters and outcomes for several decades. Formal, prospective study is warranted to clarify the role of this adjunct in all hemodynamic unstable patients.

"Thinking" vs. "Talking": Differential Autocrine Inflammatory Networks in Isolated Primary Hepatic Stellate Cells and Hepatocytes under Hypoxic Stress

We hypothesized that isolated primary mouse hepatic stellate cells (HSC) and hepatocytes (HC) would elaborate different inflammatory responses to hypoxia with or without reoxygenation. We further hypothesized that intracellular information processing (“thinking”) differs from extracellular information transfer (“talking”) in each of these two liver cell types. Finally, we hypothesized that the complexity of these autocrine responses might only be defined in the absence of other non-parenchymal cells or trafficking leukocytes. Accordingly, we assayed 19 inflammatory mediators in the cell culture media (CCM) and whole cell lysates (WCLs) of HSC and HC during hypoxia with and without reoxygenation. We applied a unique set of statistical and data-driven modeling techniques including Two-Way ANOVA, hierarchical clustering, Principal Component Analysis (PCA) and Network Analysis to define the inflammatory responses of these isolated cells to stress. HSC, under hypoxic and reoxygenation stresses, both expressed and secreted larger quantities of nearly all inflammatory mediators as compared to HC. These differential responses allowed for segregation of HSC from HC by hierarchical clustering. PCA suggested, and network analysis supported, the hypothesis that above a certain threshold of cellular stress, the inflammatory response becomes focused on a limited number of functions in both HSC and HC, but with distinct characteristics in each cell type. Network analysis of separate extracellular and intracellular inflammatory responses, as well as analysis of the combined data, also suggested the presence of more complex inflammatory “talking” (but not “thinking”) networks in HSC than in HC. This combined network analysis also suggested an interplay between intracellular and extracellular mediators in HSC under more conditions than that observed in HC, though both cell types exhibited a qualitatively similar phenotype under hypoxia/reoxygenation. Our results thus suggest that a stepwise series of computational and statistical analyses may help decipher how cells respond to environmental stresses, both within the cell and in its secretory products, even in the absence of cooperation from other cells in the liver.

Hemorrhagic Shock and the Microvasculature

The microvasculature plays a central role in the pathophysiology of hemorrhagic shock and is also involved in arguably all therapeutic attempts to reverse or minimize the adverse consequences of shock. Microvascular studies specific to hemorrhagic shock were reviewed and broadly grouped depending on whether data were obtained on animal or human subjects. Dedicated sections were assigned to microcirculatory changes in specific organs, and major categories of pathophysiological alterations and mechanisms such as oxygen distribution, ischemia, inflammation, glycocalyx changes, vasomotion, endothelial dysfunction, and coagulopathy as well as biomarkers and some therapeutic strategies. Innovative experimental methods were also reviewed for quantitative microcirculatory assessment as it pertains to changes during hemorrhagic shock. The text and figures include representative quantitative microvascular data obtained in various organs and tissues such as skin, muscle, lung, liver, brain, heart, kidney, pancreas, intestines, and mesentery from various species including mice, rats, hamsters, sheep, swine, bats, and humans. Based on reviewed findings, a new integrative conceptual model is presented that includes about 100 systemic and local factors linked to microvessels in hemorrhagic shock. The combination of systemic measures with the understanding of these processes at the microvascular level is fundamental to further develop targeted and personalized interventions that will reduce tissue injury, organ dysfunction, and ultimately mortality due to hemorrhagic shock. Published 2018. Compr Physiol 8:61-101, 2018.

Time to aortic occlusion: It's all about access

INTRODUCTION

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a less invasive method of proximal aortic occlusion compared with resuscitative thoracotomy with aortic cross-clamping (RTACC). This study compared time to aortic occlusion with REBOA and RTACC, both including and excluding time required for common femoral artery (CFA) cannulation.

METHODS

This was a retrospective, single-institution review of REBOA or RTACC performed between February 2013 and January 2016. Time of skin incision to aortic cross-clamp for RTACC, time required for CFA cannulation by percutaneous and open methods, and time from guide-wire insertion to balloon inflation at Zone 1 for REBOA, were obtained from videographic recordings.

RESULTS

Eighteen RTACC and 21 REBOAs were performed. Median (Q1, Q3) time from skin incision to aortic cross-clamping was 317 seconds (227, 551 seconds). Median (Q1, Q3) time from start of arterial access to Zone 1 balloon occlusion was 474 seconds (431, 572 seconds) (vs. RTACC, p = 0.01). All REBOA procedures were performed with the same device. The median time to complete CFA cannulation was 247 seconds (range, 164-343 seconds), with no difference between percutaneous or open procedures (p = 0.07). The median (Q1, Q3) time to aortic occlusion in REBOA once arterial access had been established was 245 seconds (179, 295.5 seconds), which was significantly shorter than RTACC (p = 0.003).

CONCLUSIONS

Once CFA access is achieved, time to aortic occlusion is faster with REBOA. Time to aortic occlusion is less than the time required to cannulate the CFA either by percutaneous or open approaches, emphasizing the importance of accurate and expedient CFA access. Resuscitative endovascular balloon occlusion of the aorta may represent a feasible alternative to thoracotomy for aortic occlusion. Time to aortic occlusion will likely decrease with the advent of newer REBOA technology. The rate-limiting portion of REBOA continues to be obtaining CFA access.

LEVEL OF EVIDENCE

Therapeutic, level V.

Alterations of Mg2+ After Hemorrhagic Shock

Hemorrhagic shock is generally characterized by hemodynamic instability with cellular hypoxia and diminishing cellular function, resulting from an imbalance between systemic oxygen delivery and consumption and redistribution of fluid and electrolytes. Magnesium (Mg) is the fourth most abundant cation overall and second most abundant intracellular cation in the body and an essential cofactor for the energy production and cellular metabolism. Data for blood total Mg (tMg; free-ionized, protein-bound, and anion-bound forms) and free Mg²⁺ levels after a traumatic injury are inconsistent and only limited information is available on hemorrhagic effects on free Mg²⁺ as the physiologically active form. The aim of this study was to determine changes in blood Mg²⁺ and tMg after hemorrhage in rats identifying mechanism and origin of the changes in blood Mg²⁺. Hemorrhagic shock produced significant increases in blood Mg²⁺, plasma tMg, Na⁺, K⁺, Cl^-, anion gap, partial pressures of oxygen, glucose, and blood urea nitrogen but significant decreases in RBC tMg, blood Ca²⁺, HCO₃^-, pH, partial pressures of carbon dioxide, hematocrit, hemoglobin, total cholesterol, and plasma/RBC ATP. During hemorrhagic shock, K⁺, anion gap, and BUN showed significant positive correlations with changes in blood Mg²⁺ level, while Ca²⁺, pH, and T-CHO correlated to Mg²⁺ in a negative manner. In conclusion, hemorrhagic shock induced an increase in both blood-free Mg²⁺ and tMg, resulted from Mg²⁺ efflux from metabolic damaged cell with acidosis and ATP depletion.

Hydrogen gas inhalation inhibits progression to the "irreversible" stage of shock after severe hemorrhage in rats

BACKGROUND

Mortality of hemorrhagic shock primarily depends on whether or not the patients can endure the loss of circulating volume until radical treatment is applied. We investigated whether hydrogen (H2) gas inhalation would influence the tolerance to hemorrhagic shock and improve survival.

METHODS

Hemorrhagic shock was achieved by withdrawing blood until the mean arterial blood pressure reached 30-35 mm Hg. After 60 minutes of shock, the rats were resuscitated with a volume of normal saline equal to four times the volume of shed blood. The rats were assigned to either the H2 gas (1.3% H2, 26% O2, 72.7% N2)-treated group or the control gas (26% O2, 74% N2)-treated group. Inhalation of the specified gas mixture began at the initiation of blood withdrawal and continued for 2 hours after fluid resuscitation.

RESULTS

The survival rate at 6 hours after fluid resuscitation was 80% in H2 gas-treated rats and 30% in control gas-treated rats (p < 0.05). The volume of blood that was removed through a catheter to induce shock was significantly larger in the H2 gas-treated rats than in the control rats. Despite losing more blood, the increase in serum potassium levels was suppressed in the H2 gas-treated rats after 60 minutes of shock. Fluid resuscitation completely restored blood pressure in the H2 gas-treated rats, whereas it failed to fully restore the blood pressure in the control gas-treated rats. At 2 hours after fluid resuscitation, blood pressure remained in the normal range and metabolic acidosis was well compensated in the H2 gas-treated rats, whereas we observed decreased blood pressure and uncompensated metabolic acidosis and hyperkalemia in the surviving control gas-treated rats.

CONCLUSIONS

H2 gas inhalation delays the progression to irreversible shock. Clinically, H2 gas inhalation is expected to stabilize the subject until curative treatment can be performed, thereby increasing the probability of survival after hemorrhagic shock.

The grapes and wrath: using resveratrol to treat the pathophysiology of hemorrhagic shock

Resveratrol, a naturally occurring polyphenol found in grapes, has been shown to reduce oxidative stress and inflammation in a variety of conditions. Recently, resveratrol has been investigated as a potential adjunct to resuscitation therapy for hemorrhagic shock-a condition characterized by tissue hypoxia, mitochondrial dysfunction, and inflammation. Although standard resuscitation restores tissue perfusion, it can exacerbate oxidative stress and organ damage. In rodent models of severe hemorrhagic shock, resveratrol mitigates reperfusion injury, preserves organ function, and improves survival. While many of these benefits can be attributed to its ability to activate sirtuin 1, resveratrol interacts with many targets that are relevant to ischemia-reperfusion. Here, we explore the probable mechanisms, potential benefits, and possible problems associated with administering resveratrol as an adjunct during resuscitation of hemorrhagic shock.

A Brief Review of OPT101 Sensor Application in Near-Infrared Spectroscopy Instrumentation for Intensive Care Unit Clinics

The optoelectronic sensor OPT101 have merits in advanced optoelectronic response characteristics at wavelength range for medical near-infrared spectroscopy and small-size chip design with build-in trans-impedance amplifier. Our lab is devoted to developing a series of portable near-infrared spectroscopy (NIRS) devices embedded with OPT101 for applications in intensive care unit clinics, based on NIRS principle. Here we review the characteristics and advantages of OPT101 relative to clinical NIRS instrumentation, and the most recent achievements, including early-diagnosis and therapeutic effect evaluation of thrombus, noninvasive monitoring of patients' shock severity, and fatigue evaluation. The future prospect on OPT101 improvements in noninvasive clinical applications is also discussed.

Effects of interleukin-17 on human retinal vascular endothelial cell capillary tube formation in vitro

The present study aimed to investigate the effect of and mechanism underlying interleukin (IL)‑17 on human retinal vascular endothelial cell (HREC) capillary tube formation in vitro. The expression of IL‑17 receptor (IL‑17R) in human HRECs was quantified using reverse transcriptase‑polymerase chain reaction (RT‑PCR) and western blot analyses. The roles of IL‑17 in HREC migration and capillary tube formation were detected using a wound scratching assay and three‑dimensional Matrigel assay, respectively, in vitro. HREC proliferation was examined using a cell counting kit‑8 assay with administration of serial doses of IL‑17. The effects of IL‑17 on the expression of vascular endothelial growth factor (VEGF), intercellular cell adhesion molecule (ICAM)‑1, IL‑6 and IL‑8 in HRECs were evaluated using RT‑PCR and western blot analyses. The results revealed that the HRECs expressed IL‑17R, and the number of intact capillary tubes formed by HRECs in the presence of IL‑17 was markedly higher, compared with that in the blank control group. The wound scratching assay showed that the numbers of migrated HRECs stimulated with IL‑17 at concentrations of 100 or 500 ng/ml were significantly higher, compared with the number in the control group. The RT‑PCR and western blot analyses showed that IL‑17 significantly promoted the expression of VEGF, ICAM‑1, IL‑6 and IL‑8 by the HRECs. The proliferation of HRECs in the presence of IL‑17 was also significantly increased. Therefore, IL‑17 increased HREC capillary tube formation through promoting HREC migration, proliferation, and expression levels of VEGF, ICAM‑1, IL‑6 and IL-8.

Surgical Critical Care for the Trauma Patient with Cardiac Disease

The elderly population is rapidly increasing in number. Therefore, geriatric trauma is becoming more prevalent. All practitioners caring for geriatric trauma patients should be familiar with the structural and functional changes naturally occurring in the aging heart, as well as common preexisting cardiac diseases in the geriatric population. Identification of the shock state related to cardiac dysfunction and targeted assessment of perfusion and resuscitation are important when managing elderly patients. Finally, management of cardiac dysfunction in the trauma patient includes an appreciation of the inherent effects of trauma on cardiac function.

Shock associated with endothelial dysfunction in omental microvessels

BACKGROUND

Impaired microvascular function leads to a poor outcome in a variety of medical conditions. Our aim was to determine whether vasodilator responses to acetylcholine (Ach) are impaired in human omental arterioles from patients with severe trauma.

MATERIALS AND METHODS

Patients with massive blood loss and severe shock requiring damage control procedures were included. Tissues were collected at the first (FEL) and the second explorative laparotomy (SEL). Control tissues were collected from nontrauma patients. Freshly isolated 50-200-μm-diameter omental arterioles were analysed using videomicroscopy. Dihydroethidine and DCF-DA fluorescence were used to assess reactive oxygen species (ROS) production. MnTBAP was used to determine the contribution of excess vascular superoxide contribution to endothelial dysfunction.

RESULTS

After constriction (30-50%) with endothelin-1, dilation to graded doses of Ach (10^-9 -10^-4 M) was greater in control vessels compared to FEL and SEL (max dilation at 10^-4 M (MD) = 25 ± 3%, n = 8; and 59 ± 8%, n = 8, respectively, and controls MD = 93 ± 10%, n = 6, P < 0·05). Fluorescence imaging of ROS production showed significant increases in superoxide (225·46 ± 12·86; 215·77 ± 10·75 vs. 133·75 ± 7·26, arbitrary units; P < 0·05) and peroxide-related ROS (240·8 ± 20·42; 234·59 ± 28·86, vs. 150·78 ± 15·65, arbitrary units; P < 0·05), in FEL and SEL microvessels compared to control, respectively. FEL pretreated with MnTBAP demonstrated significant improvement in Ach-induced vasodilation (25·5 ± 3·0% vs. 79·5 ± 8·2%; P < 0·05).

CONCLUSIONS

Severe shock associated with microvascular endothelial dysfunction enhances production of ROS in human omental tissues. The altered flow regulation may contribute to a mismatch between local blood supply and demand, exacerbating abnormal tissue perfusion and function.