Hemodilution as a result of aggressive fluid resuscitation aggravates coagulopathy in a rat model of uncontrolled hemorrhagic shock

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

BACKGROUND

The 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.

OBJECTIVE

To 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.

METHOD

A 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.

RESULT

The 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%).

CONCLUSION

BRS 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.

Elamipretide mitigates ischemia-reperfusion injury in a swine model of hemorrhagic shock

ischemia-reperfusion injury (IRI) after hemorrhage is potentiated by aortic occlusion or resuscitative endovascular balloon occlusion of the aorta (REBOA). Given the central role of mitochondrial injury in shock, we hypothesized that Elamipretide, a peptide that protects mitochondria, would mitigate IRI after hemorrhagic shock and REBOA. Twelve pigs were subjected to hemorrhagic shock and 45 min of REBOA. After 25 min of REBOA, animals received either saline or Elamipretide. Animals were transfused with autologous blood during balloon deflation, and pigs were resuscitated with isotonic crystalloids and norepinephrine for 4.25 h. Elamipretide-treated animals required less crystalloids than the controls (62.5 [50-90] and 25 [5-30] mL/kg, respectively), but similar amounts of norepinephrine (24.7 [8.6-39.3] and 9.7 [2.1-12.5] mcg/kg, respectively). Treatment animals had a significant reduction in serum creatinine (control: 2.7 [2.6-2.8]; Elamipretide: 2.4 [2.4-2.5] mg/dL; p = 0.04), troponin (control: 3.20 [2.14-5.47] ng/mL, Elamipretide: 0.22 [0.1-1.91] ng/mL; p = 0.03), and interleukin-6 concentrations at the end of the study. There were no differences in final plasma lactate concentration. Elamipretide reduced fluid requirements and protected the kidney and heart after profound IRI. Further understanding the subcellular consequences of REBOA and mitochondrial rescue will open new therapeutic avenues for patients suffering from IRI after hemorrhage.

Observation on the effectiveness and safety of sodium bicarbonate Ringer's solution in the early resuscitation of traumatic hemorrhagic shock: a clinical single-center prospective randomized controlled trial

Background

Traumatic hemorrhagic shock (THS) is the main cause of death in trauma patients with high mortality. Rapid control of the source of bleeding and early resuscitation are crucial to clinical treatment. Guidelines recommend isotonic crystal resuscitation when blood products are not immediately available. However, the selection of isotonic crystals has been controversial. Sodium bicarbonate Ringer solutions (BRS), containing sodium bicarbonate, electrolyte levels, and osmotic pressures closer to plasma, are ideal. Therefore, in this study, we will focus on the effects of BRS on the first 6 h of resuscitation, complications, and 7-day survival in patients with THS.

Methods

/design.

This single-center, prospective, randomized controlled trial will focus on the efficacy and safety of BRS in early THS resuscitation. A total of 400 adults THS patients will be enrolled in this study. In addition to providing standard care, enrolled patients will be randomized in a 1:1 ratio to receive resuscitation with BRS (test group) or sodium lactate Ringer’s solution (control group) until successful resuscitation from THS. Lactate clearance at different time points (0.5, 1, 1.5, 3, and 6 h) and shock duration after drug administration will be compared between the two groups as primary end points. Secondary end points will compare coagulation function, temperature, acidosis, inflammatory mediator levels, recurrence of shock, complications, medication use, and 7-day mortality between the two groups. Patients will be followed up until discharge or 7 days after discharge.

Discussion

At present, there are still great differences in the selection of resuscitation fluids, and there is a lack of systematic and detailed studies to compare and observe the effects of various resuscitation fluids on the effectiveness and safety of early resuscitation in THS patients. This trial will provide important clinical data for resuscitation fluid selection and exploration of safe dose of BRS in THS patients.

Trial registration.

Chinese Clinical Trial Registry (ChiCTR), ChiCTR2100045044. Registered on 4 April 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06752-5.

Viscoelastic Coagulation Testing in Exotic Animals

Whole blood viscoelastic coagulation testing (VCT) allows global assessment of hemostasis and fibrinolysis. Although not widely used in exotic animal practice, VCT has been used in exotic animal research settings. Differences in patient demographics and analytical variables can result in dramatically different results with the same analyzer. To improve the utility of VCT in exotic animal medicine, standardization of protocols is necessary to facilitate the establishment of reference intervals. Despite these challenges, the quantitative/qualitative nature of VCT has already proved its real-world value to some clinicians.

Toxic medications in Leber's hereditary optic neuropathy

Leber's hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disorder characterized by acute bilateral vision loss. The pathophysiology involves reactive oxygen species (ROS), which can be affected by medications. This article reviews the evidence for medications with demonstrated and theoretical effects on mitochondrial function, specifically in relation to increased ROS production. The data reviewed provides guidance when selecting medications for individuals with LHON mutations (carriers) and are susceptible to conversion to affected. However, as with all medications, the proven benefits of these therapies must be weighed against, in some cases, purely theoretical risks for this unique patient population.

Defining Dogma: Quantifying Crystalloid Hemodilution in a Prospective Randomized Control Trial with Blood Donation as a Model for Hemorrhage

BACKGROUND

The concept of hemodilution after blood loss and crystalloid infusion is a surgical maxim that remains unproven in humans. We sought to quantify the effect of hemodilution after crystalloid administration in voluntary blood donors as a model for acute hemorrhage.

STUDY DESIGN

A prospective, randomized control trial was conducted in conjunction with community blood drives. Donors were randomized to receive no IV fluid (noIVF), 2 liters of normal saline (NS), or 2 liters lactated Ringer's (LR) after blood donation. Blood samples were taken before donation of 500 mL of blood, immediately after donation, and after IV fluid administration. Hemoglobin (Hgb) was measured at each time point. Hemoglobin measurements between time points were compared between groups using standard statistical tests and the Bonferroni correction for multiple comparisons. Statistical significance was set at p ≤ 0.0167.

RESULTS

Of 165 patients consented, 157 patients completed the study. Average pre-donation Hgb was 14.3 g/dL. There was no difference in the mean Hgb levels after blood donation between the 3 groups (p > 0.05). Compared with the control group, there was a significant drop in Hgb in the crystalloid infused groups from the post-donation level to post-resuscitation (13.2 vs 12.1 vs 12.2 g/dL, p < 0.0001). A formula was created to predict hemoglobin levels from a given estimated blood loss (EBL) and volume replacement (VR): Hemodilution Hgb = (mean pre-donation Hgb - hemorrhage Hgb drop - equilibration hemoglobin drop - resuscitation Hgb drop) = Mean pre-donation Hgb - [(EBL/TBV)*l] - [(EBL/TBV)*h] - [(VR/TBV)*r], l = 5.111g/dL = blood loss coefficient, h = 6.722 g/dL = equilibration coefficient, r = 2.617g/dL = resuscitation coefficient.

CONCLUSIONS

This study proves the concept of hemodilution and derived a mathematical relationship between blood loss and resuscitation. These data may help to estimate response of hemoglobin levels to blood loss and fluid resuscitation in clinical practice.

Acute high-altitude exposure shortens survival after uncontrolled hemorrhagic shock in rats

BACKGROUND

Uncontrolled hemorrhage (UH) remains the most common cause of death on the battlefield. This study examined the pathophysiological characteristics of UH in rats acutely exposed to high altitude.

MATERIAL AND METHODS

Rats raised at sea level were randomly divided into two groups. Rats in the high-altitude group were exposed to hypobaric hypoxia in a hypobaric chamber (simulating 4000 m above sea level) for 2 d and then were performed a hemorrhagic shock protocol in the hypobaric chamber. Rats that underwent the same hemorrhage procedure at sea level were used as control. Anesthetized rats were bled to maintain their mean arterial pressure at 45 mmHg for 1 h. The distal quarter of the tail was amputated to allow free blood loss. After 1 h, the tail cut was ligated to induce hemostasis. mean arterial pressure, acid-base balance, blood loss, and survival were recorded. Rats were killed, and tissues were obtained for histological analysis.

RESULTS

Rats in the high-altitude group suffered less uncontrolled blood loss, more severe acidosis (lower pH and base excess), and inferior tissue oxygen supply (lower oxygen saturation and higher arterial lactate concentration) during the hemorrhage periods compared with the control group. Survival rates were significantly lower in the high-altitude group than those in the control group (P < 0.05), which was consistent with the results of pathological tissue injury.

CONCLUSIONS

In this rat model of hemorrhagic shock, acute high-altitude exposure resulted in decreased UH but more serious hemorrhagic shock injuries than that at sea level.

Hypotensive Resuscitation with Hypertonic Saline Dextran Improves Survival in a Rat Model of Hemorrhagic Shock at High Altitude

OBJECTIVE

To compare the efficacy of hypotensive resuscitation with hypertonic saline dextran 70 (HSD) and lactated Ringer (LR) solutions in a rat model of hemorrhagic shock at a simulated altitude of 4,000 m.

METHODS

Anesthetized rats were bled to maintain their mean arterial pressure (MAP) at 45 mm Hg for 1 h. The distal quarter of the tail was then amputated to allow free blood loss; rats were simultaneously resuscitated with 4 mL kg HSD (HSD group, n = 10) or 4 mL kg LR (LR group, n = 10), followed by hypotensive resuscitation with LR to maintain MAP at 55 to 60 mm Hg for 1 h. A control group received no resuscitation (n = 10). Afterward, the cut end of the tail was ligated. The MAP, acid-base balance, blood loss, volume of fluid infused, and survival were recorded.

RESULTS

Compared with controls, HSD resuscitation improved MAP (without increasing uncontrolled blood loss), increased arterial pH and oxygen saturation (SaO2), decreased arterial lactate concentration at the end of resuscitation, and resulted in higher survival rate (P < 0.05). Hypotensive resuscitation with LR also maintained higher MAP, pH, and SaO2 than the control group, but was associated with increased blood loss and inferior survival (P > 0.05).

CONCLUSIONS

For hemorrhagic shock at simulated high altitude, resuscitation of rats with a bolus of HSD was associated with reduced blood loss and serum lactate concentration, and superior SaO2, hemoglobin concentration and survival rate, compared with LR solution.

Experimental Animal Models of Traumatic Coagulopathy: A Systematic Review

BACKGROUND

Perturbations in coagulation function are common following trauma and are associated with poor clinical outcomes. Traditionally considered an iatrogenic process, it is now recognized that an acute coagulation dysfunction develops prior to medical intervention. The mechanisms underlying the development of this acute traumatic coagulopathy remain poorly understood. Preclinical animal research is a necessary adjunct to improve mechanistic understanding and management of this condition. This review aims to identify and evaluate existing animal models of traumatic coagulopathy for clinical relevance.

METHODS

A structured search of MEDLINE/PubMed was performed in September 2014 in accordance with the PRISMA guidelines.

RESULTS

A total of 62 relevant publications describing 27 distinct models of traumatic coagulopathy were identified. Porcine models predominated, and hemodilution in isolation or in combination with hypothermia and/or acidosis was the principal mechanism for inducing coagulopathy. Acute coagulation changes in response to tissue injury and hemorrhage were evident in five publications, and pathophysiological evaluation of postulated mechanisms was performed in three studies.

CONCLUSIONS

There are few clinically relevant animal models that reflect the contemporary understanding of traumatic coagulopathy. This relative deficiency highlights the need for further development of valid and reproducible animal models of trauma. Well-designed models will facilitate improved mechanistic understanding and development of targeted treatment strategies for traumatic coagulopathy.

Fluid resuscitation and vasopressors in severe trauma patients

PURPOSE OF REVIEW

To discuss the fluid resuscitation and the vasopressor support in severe trauma patients.

RECENT FINDINGS

A critical point is to prevent a potential increase in bleeding by an overly aggressive resuscitative strategy. Indeed, large-volume fluid replacement may promote coagulopathy by diluting coagulation factors. Moreover, an excessive level of mean arterial pressure may induce bleeding by preventing clot formation.

SUMMARY

Fluid resuscitation is the first-line therapy to restore intravascular volume and to prevent cardiac arrest. Thus, fluid resuscitation before bleeding control must be limited to the bare minimum to maintain arterial pressure to minimize dilution of coagulation factors and complications of over fluid resuscitation. However, a strategy of low fluid resuscitation needs to be handled in a flexible way and to be balanced considering the severity of the hemorrhage and the transport time. A target systolic arterial pressure of 80-90 mmHg is recommended until the control of hemorrhage in trauma patients without brain injury. In addition to fluid resuscitation, early vasopressor support may be required to restore arterial pressure and prevent excessive fluid resuscitation. It is crucial to find the best alchemy between fluid resuscitation and vasopressors, to consider hemodynamic monitoring and to establish trauma resuscitative protocols.

Freeze-dried plasma at the point of injury: from concept to doctrine

While early plasma transfusion for the treatment of patients with ongoing major hemorrhage is widely accepted as part of the standard of care in the hospital setting, logistic constraints have limited its use in the out-of-hospital setting. Freeze-dried plasma (FDP), which can be stored at ambient temperatures, enables early treatment in the out-of-hospital setting. Point-of-injury plasma transfusion entails several significant advantages over currently used resuscitation fluids, including the avoidance of dilutional coagulopathy, by minimizing the need for crystalloid infusion, beneficial effects on endothelial function, physiological pH level, and better maintenance of intravascular volume compared with crystalloid-based solutions. The Israel Defense Forces Medical Corps policy is that plasma is the resuscitation fluid of choice for selected, severely wounded patients and has thus included FDP as part of its armamentarium for use at the point of injury by advanced life savers, across the entire military. We describe the clinical rationale behind the use of FDP at the point-of-injury, the drafting of the administration protocol now being used by Israel Defense Forces advanced life support providers, the process of procurement and distribution, and preliminary data describing the first casualties treated with FDP at the point of injury. It is our hope that others will be able to learn from our experience, thus improving trauma casualty care around the world.

Effects of different types of fluid resuscitation on hepatic mitochondria and apoptosis

The aim of this study was to observe the effects of different types of fluid resuscitation on hepatic mitochondria and apoptosis in hemorrhagic shock, and the corresponding mechanisms. Forty rats were divided into five groups: Sham surgery (Sham group), shock (Shock group), Ringer's lactate resuscitation (RL group), hydroxyethyl starch resuscitation (HES group) and autologous blood resuscitation (BL group). A model of hemorrhagic shock was successfully induced in the latter four groups. The recovery objective was to maintain the mean arterial pressure (MAP) of the rats at 80 mmHg. Two hours after the end of the recovery experiment, fresh liver samples were examined in order to observe the changes in the morphology and mitochondrial membrane potential (ΔΨm). In addition, the levels of succinate dehydrogenase (SDH) activity were assessed, and a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was conducted to evaluate the level of apoptosis in the liver cells. In the Shock, RL, HES and BL groups, mitochondrial ultrastructural damage in the liver cells, significant reductions in liver cell function, liver ΔΨm and SDH activity, and the apoptosis of hepatocytes were more apparent compared with those in the Sham group. In the BL group, compared with the RL and HES groups, the injuries to the mitochondrial ultrastructure and liver cell function were significantly reduced, the hepatic ΔΨm and SDH activity were significantly increased and the hepatocyte apoptosis index (AI) was significantly reduced (P<0.05). In conclusion, in a rat model of hemorrhagic shock, different methods of fluid resuscitation may improve the liver cells with regard to mitochondrial ultrastructure and function, the stability of liver ΔΨm, the activity of SDH and the inhibition of liver cell apoptosis. The results indicate that infusion with autologous blood followed by RL solution is a preferable method of fluid resuscitation compared with HES.

Efficacy of centhaquin as a small volume resuscitative agent in severely hemorrhaged rats

Centhaquin has been reported to be an effective resuscitative agent. The present study was carried out to determine resuscitative effect of centhaquin when administered using a small volume of 3% hypertonic saline (HS) to hemorrhaged rats. Sprague-Dawley rats were anesthetized with urethane, and a pressure catheter SPR-320 was placed in the left femoral artery; another pressure-volume catheter SPR-869 was placed into the left ventricle. Hemorrhage was induced by withdrawing blood and mean arterial pressure (MAP) was maintained at 35 mm Hg for 30 minutes after which resuscitation was performed. Animals were divided in 2 groups: group A received HS and group B received centhaquin (0.05 mg/kg) dissolved in HS. The time by which MAP fell back to 35 mm Hg was observed at that time all animals were administered fresh blood. It was found that centhaquin significantly reduced blood lactate and improved cardiac output and MAP of hemorrhaged rats compared with HS. The time by which MAP fell back to 35 mm Hg in rats treated with HS was 55 ± 6 minutes, whereas it was 161 ± 14 minutes in centhaquin treated rats. Survival time following administration of fresh blood was 79 ± 7 minutes in vehicle-treated group, whereas it was 105 ± 9 minutes in centhaquin-treated rats. The total time of survival of rats treated with HS or centhaquin was 134 ± 12 minutes and 266 ± 16 minutes, respectively. Centhaquin, in small volume, maintained MAP of hemorrhaged rats for a considerable long time and improved the survival time.