Deleterious effects of aggressive rapid crystalloid resuscitation on treatment of hyperinflammatory response and lung injury induced by hemorrhage in aging rats

The Effects of Resuscitative Fluid Therapy on the Endothelial Surface Layer

The goal of resuscitative fluid therapy is to rapidly expand circulating blood volume in order to restore tissue perfusion. Although this therapy often serves to improve macrohemodynamic parameters, it can be associated with adverse effects on the microcirculation and endothelium. The endothelial surface layer (ESL) provides a protective barrier over the endothelium and is important for regulating transvascular fluid movement, vasomotor tone, coagulation, and inflammation. Shedding or thinning of the ESL can promote interstitial edema and inflammation and may cause microcirculatory dysfunction. The pathophysiologic perturbations of critical illness and rapid, large-volume fluid therapy both cause shedding or thinning of the ESL. Research suggests that restricting the volume of crystalloid, or “clear” fluid, may preserve some ESL integrity and improve outcome based on animal experimental models and preliminary clinical trials in people. This narrative review critically evaluates the evidence for the detrimental effects of resuscitative fluid therapy on the ESL and provides suggestions for future research directions in this field.

Cytochrome P450 Epoxygenase 2J2 Protects Against Lung Ischemia/Reperfusion Injury by Activating the P13K/Akt/GSK-3-β/NF-kB Signaling Pathway During Deep Hypothermic Low Flow in Mice

BACKGROUND

Cytochrome P450 epoxygenase 2J2 (CYP2J2) metabolizes arachidonic acid to epoxyeicosatrienoic acids, which exert anti-inflammatory effects and alleviate oxidative stress in the cardiovascular system. Our previous work revealed that CYP2J2 is expressed in pulmonary artery endothelial cells. It was therefore hypothesized that CYP2J2 overexpression may prevent lung ischemia/reperfusion injury (LIRI) in 3-week-old C57BL/6 mice during deep hypothermic low flow (DHLF). This study aimed to establish whether CYP2J2 protects against LIRI and the mechanisms of CYP2J2 overexpression during DHLF in mice. The aim of this study was to explore the effects of DHLF on lung tissue in mice and to find out the regularity of this process, so as to provide theoretical data for lung tissue protection in children undergoing this process in clinic.

METHODS

A 3-week-old C57BL/6 mouse model was used to mimic LIRI conditions during DHLF by clamping the left pulmonary artery and left main bronchus for 120 min, followed by reperfusion for 2 h. The body temperature of the mice was maintained between 18°C and 19°C to induce DHLF.

RESULTS

During DHLF, lung ischemia/reperfusion increased the left lung wet/dry weight, the left lung weight/body weight ratio, the protein concentration in bronchoalveolar lavage fluid, and the concentration of proinflammatory mediators in the lungs, including interleukin (IL)-1, IL-8, and necrosis factor (NF)-α, and decreased the concentration of the anti-inflammatory mediator IL-10. Furthermore, activation of NF-κB p65 and degradation of IKBα were remarkably increased in lung tissues after ischemia/reperfusion. The CYP2J2 overexpression group showed the opposite results (P < 0.05), and p-Akt1 and p-GSK-3β expression were significantly higher in the CYP2J2 overexpression group (P < 0.05). Moreover, the changes in IL-1, IL-8, tumor necrosis factor-α, IL-10, p-Akt1, p-GSK-3β, NF-κB p65, and IKBα were reversed in the Akt1 gene heterozygous knockout group, and lung damage was significantly higher in the Akt1 gene heterozygous knockout group than in the CYP2J2 overexpression group. CYP2J2 overexpression can protect against LIRI, whereas Akt1 gene heterozygous knockout in mice can abolish this protective effect.

CONCLUSIONS

CYP2J2 overexpression can protect against LIRI by activating the P13K/Akt/GSK-3β/NF-kB signaling pathway during DHLF. Thus, changing CYP2J2 expression can be a novel strategy for the prevention and treatment of LIRI during DHLF.

Trauma Hemostasis and Oxygenation Research Network position paper on the role of hypotensive resuscitation as part of remote damage control resuscitation

The Trauma Hemostasis and Oxygenation Research (THOR) Network has developed a consensus statement on the role of permissive hypotension in remote damage control resuscitation (RDCR). A summary of the evidence on permissive hypotension follows the THOR Network position on the topic. In RDCR, the burden of time in the care of the patients suffering from noncompressible hemorrhage affects outcomes. Despite the lack of published evidence, and based on clinical experience and expertise, it is the THOR Network's opinion that the increase in prehospital time leads to an increased burden of shock, which poses a greater risk to the patient than the risk of rebleeding due to slightly increased blood pressure, especially when blood products are available as part of prehospital resuscitation.The THOR Network's consensus statement is, "In a casualty with life-threatening hemorrhage, shock should be reversed as soon as possible using a blood-based HR fluid. Whole blood is preferred to blood components. As a part of this HR, the initial systolic blood pressure target should be 100 mm Hg. In RDCR, it is vital for higher echelon care providers to receive a casualty with sufficient physiologic reserve to survive definitive surgical hemostasis and aggressive resuscitation. The combined use of blood-based resuscitation and limiting systolic blood pressure is believed to be effective in promoting hemostasis and reversing shock".

Transduced PEP-1-Heme Oxygenase-1 Fusion Protein Attenuates Lung Injury in Septic Shock Rats

Oxidative stress and inflammation have been identified to play a vital role in the pathogenesis of lung injury induced by septic shock. Heme oxygenase-1 (HO-1), an effective antioxidant and anti-inflammatory and antiapoptotic substance, has been used for the treatment of heart, lung, and liver diseases. Thus, we postulated that administration of exogenous HO-1 protein transduced by cell-penetrating peptide PEP-1 has a protective role against septic shock-induced lung injury. Septic shock produced by cecal ligation and puncture caused severe lung damage, manifested in the increase in the lung wet/dry ratio, oxidative stress, inflammation, and apoptosis. However, these changes were reversed by treatment with the PEP-1-HO-1 fusion protein, whereas lung injury in septic shock rats was alleviated. Furthermore, the septic shock upregulated the expression of Toll-like receptor 4 (TLR4) and transcription factor NF-κB, accompanied by the increase of lung injury. Administration of PEP-1-HO-1 fusion protein reversed septic shock-induced lung injury by downregulating the expression of TLR4 and NF-κB. Our study indicates that treatment with HO-1 protein transduced by PEP-1 confers protection against septic shock-induced lung injury by its antioxidant, anti-inflammatory, and antiapoptotic effects.

Effect of hypertonic saline in the pretreatment of lung donors with hemorrhagic shock

BACKGROUND

Hemorrhagic shock-induced lung edema and inflammation are two of the main reasons for the rejection of lungs donated for transplantation. Hypertonic saline (HS) induces intravascular volume expansion and has considerable immunomodulating effects that might minimize edema. Our hypothesis is based on the use of a hypertonic solution for treatment of donors who are in shock in an attempt to increase the supply of lungs for transplantation.

METHODS

A total of 80 rats were allocated to four groups: one group was given an infusion of normal saline (NS; n = 20), one group received HS; n = 20, a sham group (n = 20), and a Shock group (n = 20). Half of the lungs from each group were evaluated in an ex vivo perfusion system, and the other half was used for measurements of cytokine levels and neutrophil counts.

RESULTS

In the ex vivo perfusion assessment, the pulmonary artery pressures of the animals in the NS and HS groups did not exhibit significant differences compared with those in the sham group (P > 0.05) but were lower than those in the Shock group (P < 0.01). Furthermore, the tumor necrosis factor-α levels and neutrophil counts were lower in the HS group than those in the Shock group (P < 0.01) and did not exhibit significant differences compared with those in either the NS and Sham groups (P > 0.05).

CONCLUSIONS

We showed that HS was equivalent to isotonic saline and contributed to the treatment of lungs subjected to hemorrhagic shock.

Comparative Evaluation of Crystalloid Resuscitation Rate in a Human Model of Compensated Haemorrhagic Shock

Introduction:

The most effective rate of fluid resuscitation in haemorrhagic shock is unknown.

Methods:

We performed a randomized crossover pilot study in a healthy volunteer model of compensated haemorrhagic shock. Following venesection of 15 mL/kg of blood, participants were randomized to 20 mL/kg of crystalloid over 10 min (FAST treatment) or 30 min (SLOW treatment). The primary end point was oxygen delivery (DO₂). Secondary end points included pressure and flow-based haemodynamic variables, blood volume expansion, and clinical biochemistry.

Results:

Nine normotensive healthy adult volunteers participated. No significant differences were observed in DO₂ and biochemical variables between the SLOW and FAST groups. Blood volume was reduced by 16% following venesection, with a corresponding 5% reduction in cardiac index (CI) (P < 0.001). Immediately following resuscitation the increase in blood volume corresponded to 54% of the infused volume under FAST treatment and 69% of the infused volume under SLOW treatment (P = 0.03). This blood volume expansion attenuated with time to 24% and 25% of the infused volume 30 min postinfusion. During fluid resuscitation, blood pressure was higher under FAST treatment. However, CI paradoxically decreased in most participants during the resuscitation phase; a finding not observed under SLOW treatment.

Conclusion:

FAST or SLOW fluid resuscitation had no significant impact on DO₂ between treatment groups. In both groups, changes in CI and blood pressure did not reflect the magnitude of intravascular blood volume deficit. Crystalloid resuscitation expanded intravascular blood volume by approximately 25%.

New perspectives of volemic resuscitation in polytrauma patients: a review

Nowadays, fluid resuscitation of multiple trauma patients is still a challenging therapy. Existing therapies for volume replacement in severe haemorrhagic shock can lead to adverse reactions that may be fatal for the patient. Patients presenting with multiple trauma often develop hemorrhagic shock, which triggers a series of metabolic, physiological and cellular dysfunction. These disorders combined, lead to complications that significantly decrease survival rate in this subset of patients. Volume and electrolyte resuscitation is challenging due to many factors that overlap. Poor management can lead to post-resuscitation systemic inflammation causing multiple organ failure and ultimately death. In literature, there is no exact formula for this purpose, and opinions are divided. This paper presents a review of modern techniques and current studies regarding the management of fluid resuscitation in trauma patients with hemorrhagic shock. According to the literature and from clinical experience, all aspects regarding post-resuscitation period need to be considered. Also, for every case in particular, emergency therapy management needs to be rigorously respected considering all physiological, biochemical and biological parameters.

Apelin protect against multiple organ injury following hemorrhagic shock and decrease the inflammatory response

INTRODUCTION

Hemorrhagic shock (HS) result in multiple organ injury and inflammatory response that lead to death. The exact mechanism is not clear. Apelin is an endogenous ligand of orphan G-protein coupled receptor APJ. Apelin has anti-inflammatory effects on the release of inflammatory mediators.

OBJECTIVES

To examine the protective effects of apelin against multiple organ injury and the possible involvement of inflammatory pathways.

METHODOLOGY

Male Sprague-Dawley rats (300-350 g) were subjected to hemorrhage over 60 min to reach a mean arterial blood pressure of 40 mmHg. Then, rats were treated or not with 1 mL of 10 nm/L apelin-13 intraarterially resuscitation was performed in vivo by the reinfusion of the shed blood for 30 min to restore normotension. Blood samples were collected for measurement of tumor necrosis factor (TNF) using ELISA (R and D systems). Biopsies were obtained from organs for light microscopic examination.

RESULTS

HS rats showed significant increase the levels of TNF. Apelin significantly lowered the production of TNF-α. Histological examination of hemorrhagic shocked untreated rats revealed structural damage. Less histological damage was observed in the organs of treated rats. Apelin-treatment decreased the number of inflammatory cells and mitochondrial swollen in cells.

CONCLUSION

Treatment with apelin before resuscitation protects against multiple organ injury in HS by attenuation the inflammatory response and might be a therapeutic target for HS.

A prospective, randomized trial of intravenous hydroxocobalamin versus whole blood transfusion compared to no treatment for Class III hemorrhagic shock resuscitation in a prehospital swine model

OBJECTIVES

The objective was to compare systolic blood pressure (sBP) over time in swine that have had 30% of their blood volume removed (Class III shock) and treated with intravenous (IV) whole blood or IV hydroxocobalamin, compared to nontreated control animals.

METHODS

Thirty swine (45 to 55 kg) were anesthetized, intubated, and instrumented with continuous femoral and pulmonary artery pressure monitoring. Animals were hemorrhaged a total of 20 mL/kg over a 20-minute period. Five minutes after hemorrhage, animals were randomly assigned to receive 150 mg/kg IV hydroxocobalamin solubilized in 180 mL of saline, 500 mL of whole blood, or no treatment. Animals were monitored for 60 minutes thereafter. A sample size of 10 animals per group was determined based on a power of 80% and an alpha of 0.05 to detect an effect size of at least a 0.25 difference (>1 standard deviation) in mean sBP between groups. sBP values were analyzed using repeated-measures analysis of variance (RANOVA). Secondary outcome data were analyzed using repeated-measures multivariate analysis of variance (RMANOVA).

RESULTS

There were no significant differences between hemodynamic parameters of IV hydroxocobalamin versus whole blood versus control group at baseline (MANOVA; Wilks' lambda; p = 0.868) or immediately posthemorrhage (mean sBP = 47 mm Hg vs. 41 mm Hg vs. 37 mm Hg; mean arterial pressure = 39 mm Hg vs. 28 mm Hg vs. 34 mm Hg; mean serum lactate = 1.2 mmol/L vs. 1.4 mmol/L vs. 1.4 mmol/L; MANOVA; Wilks' lambda; p = 0.348). The outcome RANOVA model detected a significant difference by time between groups (p < 0.001). Specifically, 10 minutes after treatment, treated animals showed a significant increase in mean sBP compared to nontreated animals (mean sBP = 76.3 mm Hg vs. 85.7 mm Hg vs. 51.1 mm Hg; p < 0.001). RMANOVA modeling of the secondary data detected a significant difference in mean arterial pressure, heart rate, and serum lactate (p < 0.001). Similar to sBP, 10 minutes after treatment, treated animals showed a significant increase in mean arterial pressure compared to nontreated animals (mean arterial pressure = 67.7 mm Hg vs. 61.4 mm Hg vs. 40.5 mm Hg). By 10 minutes, mean heart rate was significantly slower in treated animals compared to nontreated animals (mean heart rate = 97.3 beats/min vs. 95.2 beats/min vs. 129.5 beats/min; p < 0.05). Serum lactate, an early predictor of shock, continued to rise in the control group, whereas it did not in treated animals. Thirty minutes after treatment, serum lactate values of treated animals were significantly lower compared to nontreated animals (p < 0.05). This trend continued throughout the 60-minute observation period such that 60-minute values for lactate were 1.4 mmol/L versus 1.1 mmol/L versus 3.8 mmol/L. IV hydroxocobalamin produced a statistically significant increase in systemic vascular resistance compared to control, but not whole blood, with a concomitant decrease in cardiac output.

CONCLUSIONS

Intravenous hydroxocobalamin was more effective than no treatment and as effective as whole blood transfusion, in reversing hypotension and inhibiting rises in serum lactate in this prehospital, controlled, Class III swine hemorrhage model.