Hypertonic saline resuscitation of hemorrhagic shock diminishes neutrophil rolling and adherence to endothelium and reduces in vivo vascular leakage

Hypoalbuminemia within One Hour After Surgery as a Predictor of Post-Operative Urosepsis in Patients Undergoing Flexible Ureteroscopy Lithotripsy: A Retrospective Study

Abstract Background: To investigate retrospectively whether changes in serum albumin levels within one hour of flexible ureteroscopy (fURS) lithotripsy can be used as a predictor of post-operative urosepsis. Patients and Methods: Eligible patients with unilateral upper urinary calculi who underwent fRUS lithotripsy performed by a single surgeon at our center were included in the analysis. The patients were divided into sepsis and non-sepsis groups. The change ratio of albumin and white blood cell (WBC) count was calculated by post-operative/pre-operative index*100%. Univariable and multivariable logistic regression analyses were used to assess whether there was a correlation between risk factors and post-operative urosepsis. The receiver operating characteristic (ROC) curve was used to analyze factors that showed significant differences in multivariable logistic regression analysis. Results: A total of 314 patients were included in the analysis, 20 of whom had post-operative urosepsis and five developed septic shock; no deaths occurred. Multivariable logistic regression analysis showed that urine culture results, WBC counts within one hour after surgery, post-operative albumin levels, and the degree of albumin changes after surgery were independent predictors of post-operative urosepsis. Receiver operating characteristic curve analysis showed that noteworthy hypoalbuminemia after surgery and positive pre-operative urine culture could help screen high-risk patients for post-operative urosepsis effectively. Conclusions: Hypoalbuminemia shortly after operation can be utilized as a predictor for early diagnosis of post-operative urosepsis in patients undergoing fURS lithotripsy.

Persistent Blunting of Penumbral Leukocyte Mobilization by Beta Blockade Administered for Two Weeks After Traumatic Brain Injury

INTRODUCTION

Beta-blockers (BB) after traumatic brain injury (TBI) accelerate cognitive recovery weeks after injury. BBs also inhibit leukocyte (LEU) mobilization to the penumbral blood brain barrier (BBB) 48-h after TBI. It is unclear whether the latter effects persist longer and accompany the persistent cognitive improvement. We hypothesized that 2 wk of BB after TBI reduce penumbral BBB leukocyte-endothelial interactions.

METHODS

Thirty CD1 mice underwent TBI (controlled cortical impact, CCI: 6 m/s velocity, 1 mm depth, 3 mm diameter) or sham craniotomy followed by i.p. saline (NS) or propranolol (1, 2, 4 mg/kg) every 12 h for 14 d. On day 14, in vivo pial intravital microscopy visualized endothelial-LEU interactions and BBB microvascular leakage. Day 14 Garcia neurological test scores and animal weights were compared to preinjury levels reflecting concurrent clinical recovery.

RESULTS

LEU rolling was greatest in CCI + NS when compared to sham (P = 0.03). 4 mg/kg propranolol significantly reduced postCCI LEU rolling down to uninjured sham levels (P = 0.03). LEU adhesion and microvascular permeability were not impacted at this time interval. Untreated injured animals (CCI + NS) scored lower Garcia neurological test and greater weight loss recovery at day 14 when compared to preinjury (P < 0.05). Treatment with higher doses of propranolol (2, 4 mg/kg), improved weight loss recovery (P < 0.001).

CONCLUSIONS

LEU rolling alone, was influenced by BB therapy 14 d after TBI suggesting that certain penumbral neuroinflammatory cellular effects of BB therapy after TBI persist up to 2 wk after injury potentially explaining the pervasive beneficial effects of BBs on learning and memory.

Potentially Detrimental Effects of Hyperosmolality in Patients Treated for Traumatic Brain Injury

Hyperosmotic therapy is commonly used to treat intracranial hypertension in traumatic brain injury patients. Unfortunately, hyperosmolality also affects other organs. An increase in plasma osmolality may impair kidney, cardiac, and immune function, and increase blood-brain barrier permeability. These effects are related not only to the type of hyperosmotic agents, but also to the level of hyperosmolality. The commonly recommended osmolality of 320 mOsm/kg H2O seems to be the maximum level, although an increase in plasma osmolality above 310 mOsm/kg H2O may already induce cardiac and immune system disorders. The present review focuses on the adverse effects of hyperosmolality on the function of various organs.

Volume Resuscitation in the Acutely Hemorrhaging Patient: Historic Use to Current Applications

Acute hemorrhage in small animals results from traumatic and non-traumatic causes. This review seeks to describe current understanding of the resuscitation of the acutely hemorrhaging small animal (dog and cat) veterinary patient through evaluation of pre-clinical canine models of hemorrhage and resuscitation, clinical research in dogs and cats, and selected extrapolation from human medicine. The physiologic dose and response to whole blood loss in the canine patient is repeatable both in anesthetized and awake animals and is primarily characterized clinically by increased heart rate, decreased systolic blood pressure, and increased shock index and biochemically by increased lactate and lower base excess. Previously, initial resuscitation in these patients included immediate volume support with crystalloid and/or colloid, regardless of total volume, with a target to replace lost vascular volume and bring blood pressure back to normal. Newer research now supports prioritizing hemorrhage control in conjunction with judicious crystalloid administration followed by early consideration for administration of platelets, plasma and red blood during the resuscitation phase. This approach minimizes blood loss, ameliorates coagulopathy, restores oxygen delivery and correct changes in the glycocalyx. There are many hurdles in the application of this approach in clinical veterinary medicine including the speed with which the bleeding source is controlled and the rapid availability of blood component therapy. Recommendations regarding the clinical approach to volume resuscitation in the acutely hemorrhaging veterinary patient are made based on the canine pre-clinical, veterinary clinical and human literature reviewed.

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.

Hypertonic saline mediates the NLRP3/IL-1β signaling axis in microglia to alleviate ischemic blood-brain barrier permeability by downregulating astrocyte-derived VEGF in rats

Introduction

The aim of this study was to explore whether the antibrain edema of hypertonic saline (HS) is associated with alleviating ischemic blood‐brain barrier (BBB) permeability by downregulating astrocyte‐derived vascular endothelial growth factor (VEGF), which is mediated by microglia‐derived NOD‐like receptor protein 3 (NLRP3) inflammasome.

Methods

The infarct volume and BBB permeability were detected. The protein expression level of VEGF in astrocytes in a transient focal brain ischemia model of rats was evaluated after 10% HS treatment. Changes in the NLRP3 inflammasome, IL‐1β protein expression, and the interleukin‐1 receptor (IL1R1)/pNF‐кBp65/VEGF signaling pathway were determined in astrocytes.

Results

HS alleviated the BBB permeability, reduced the infarct volume, and downregulated the expression of VEGF in astrocytes. HS downregulates IL‐1β expression by inhibiting the activation of the NLRP3 inflammasome in microglia and then downregulates VEGF expression by inhibiting the phosphorylation of NF‐кBp65 mediated by IL‐1β in astrocytes.

Conclusions

HS alleviated the BBB permeability, reduced the infarct volume, and downregulated the expression of VEGF in astrocytes. HS downregulated IL‐1β expression via inhibiting the activation of the NLRP3 inflammasome in microglia and then downregulated VEGF expression through inhibiting the phosphorylation of NF‐кBp65 mediated by IL‐1β in astrocytes.

Colloids and the Microcirculation

Colloid solutions have been advocated for use in treating hypovolemia due to their expected effect on improving intravascular retention compared with crystalloid solutions. Because the ultimate desired effect of fluid resuscitation is the improvement of microcirculatory perfusion and tissue oxygenation, it is of interest to study the effects of colloids and crystalloids at the level of microcirculation under conditions of shock and fluid resuscitation, and to explore the potential benefits of using colloids in terms of recruiting the microcirculation under conditions of hypovolemia. This article reviews the physiochemical properties of the various types of colloid solutions (eg, gelatin, dextrans, hydroxyethyl starches, and albumin) and the effects that they have under various conditions of hypovolemia in experimental and clinical scenarios.

Hypertonic Saline in Human Sepsis: A Systematic Review of Randomized Controlled Trials

The role of hypertonic saline in sepsis remains unclear because clinical data are limited and the balance between beneficial and adverse effects is not well defined. In this systematic literature review, we searched PubMed and Embase to identify all randomized controlled trials up until January 31, 2018 in which hypertonic saline solutions of any concentration were used in patients of all ages with sepsis and compared to a cohort of patients receiving an isotonic fluid. We identified 8 randomized controlled trials with 381 patients who had received hypertonic saline. Lower volumes of hypertonic saline than of isotonic solutions were needed to achieve the desired hemodynamic goals (standardized mean difference, -0.702; 95% CI, -1.066 to -0.337; P < .001; moderate-quality evidence). Hypertonic saline administration was associated with a transient increase in sodium and chloride concentrations without adverse effects on renal function (moderate-quality evidence). Some data suggested a beneficial effect of hypertonic saline solutions on some hemodynamic parameters and the immunomodulatory profile (very low-quality evidence). Mortality rates were not significantly different with hypertonic saline than with other fluids (odds ratio, 0.946; 95% CI, 0.688-1.301; P = .733; low-quality evidence). In conclusion, in our meta-analysis of studies in patients with sepsis, hypertonic saline reduced the volume of fluid needed to achieve the same hemodynamic targets but did not affect survival.

Vasculotide, an Angiopoietin-1 Mimetic, Restores Microcirculatory Perfusion and Microvascular Leakage and Decreases Fluid Resuscitation Requirements in Hemorrhagic Shock

BACKGROUND

Microcirculatory dysfunction is associated with multiple organ failure and unfavorable patient outcome. We investigated whether therapeutically targeting the endothelial angiopoietin/Tie2 system preserves microvascular integrity during hemorrhagic shock.

METHODS

Rats were treated with the angiopoietin-1 mimetic vasculotide and subjected to hemorrhagic shock and fluid resuscitation. Microcirculatory perfusion and leakage were assessed with intravital microscopy (n = 7 per group) and Evans blue dye extravasation (n = 8 per group), respectively. The angiopoietin/Tie2 system was studied at protein and RNA level in plasma, kidneys, and lungs.

RESULTS

Hemorrhagic shock significantly reduced continuously perfused capillaries (7 ± 2 vs. 11 ± 2) and increased nonperfused vessels (9 ± 3 vs. 5 ± 2) during hemorrhagic shock, which could not be restored by fluid resuscitation. Hemorrhagic shock increased circulating angiopoietin-2 and soluble Tie2 significantly, which associated with microcirculatory perfusion disturbances. Hemorrhagic shock significantly decreased Tie2 gene expression in kidneys and lungs and induced microvascular leakage in kidneys (19.7 ± 11.3 vs. 5.2 ± 3.0 µg/g) and lungs (16.1 ± 7.0 vs. 8.6 ± 2.7 µg/g). Vasculotide had no effect on hemodynamics and microcirculatory perfusion during hemorrhagic shock but restored microcirculatory perfusion during fluid resuscitation. Interestingly, vasculotide attenuated microvascular leakage in lungs (10.1 ± 3.3 µg/g) and significantly reduced the required amount of volume supplementation (1.3 ± 1.4 vs. 2.8 ± 1.5 ml). Furthermore, vasculotide posttreatment was also able to restore microcirculatory perfusion during fluid resuscitation.

CONCLUSIONS

Targeting Tie2 restored microvascular leakage and microcirculatory perfusion and reduced fluid resuscitation requirements in an experimental model of hemorrhagic shock. Therefore, the angiopoietin/Tie2 system seems to be a promising target in restoring microvascular integrity and may reduce organ failure during hemorrhagic shock.

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.

Hypertonic Saline in the Treatment of Hemorrhagic Shock

Context

The present review discusses different studies about the treatment of hemorrhagic shock (HS) with hypertonic saline (HTS).

Evidence acquisition

We have searched the title in the most popular databases containing recent meta-analysis or randomized clinical trials (RCTs).

Results

We introduce the hemodynamic effects and mechanisms of action of HTS in HS. Evidence in this field shows controversial results. There are some data supporting the potential benefits of HTS infusion in HS. The goal of research in this field is to identify the best therapy in HS with the least mortality.

Conclusion

Our conclusion shows that although HTS can decrease inflammatory response during HS, it can attenuate hypercoagulability and cause complications. There are no data supporting less mortality while treatment with HTS versus other fluids in HS.

Low-volume resuscitation with normal saline is associated with microvascular endothelial dysfunction after hemorrhage in rats, compared to colloids and balanced crystalloids

Background

Restoration of endothelial glycocalyx (EG) barrier may be an essential therapeutic target for successful resuscitation. The aim of this study was to compare in vivo the effects of resuscitation with normal saline (NS) to lactated Ringer’s solution (LR), 5% albumin and fresh frozen plasma (FFP) on their ability to maintain EG and barrier function integrity, mitigate endothelial injury and inflammation, and restore vascular homeostasis after hemorrhagic shock.

Methods

Anesthetized rats (N = 36) were subjected to hemorrhagic shock (bled 40% of total blood volume), followed by resuscitation with 45 ml/kg NS or LR, or 15 ml/kg 5% albumin or FFP. Microhemodynamics, EG thickness, permeability, leukocyte rolling and adhesion were assessed in >180 vessels from cremaster muscle, as well as systemic measures.

Results

After hypotensive resuscitation, arterial pressure was 25% lower than baseline in all cohorts. Unlike FFP, resuscitation with crystalloids failed to restore EG thickness to baseline post shock and shedding of glycocalyx proteoglycan was significantly higher after NS. NS decreased blood flow and shear, and markedly increased permeability and leukocyte rolling/adhesion. In contrast, LR had lesser effects on increased permeability and leukocyte rolling. Albumin stabilized permeability and white blood cell (WBC) rolling/adhesion post shock, comparable to FFP.

Conclusions

Resuscitation with NS failed to inhibit syndecan-1 shedding and to repair the EG, which led to loss of endothelial barrier function (edema), decline in tissue perfusion and pronounced leukocyte rolling and adhesion. Detrimental effects of NS on endothelial and microvascular stabilization post shock may provide a pathophysiological basis to understand and prevent morbidity associated with iatrogenic resuscitation after hemorrhagic shock.

Optimal Fluid Therapy for Traumatic Hemorrhagic Shock

The resuscitation of traumatic hemorrhagic shock has undergone a paradigm shift in the last 20 years with the advent of damage control resuscitation (DCR). Major principles of DCR include minimization of crystalloid, permissive hypotension, transfusion of a balanced ratio of blood products, and goal-directed correction of coagulopathy. In particular, plasma has replaced crystalloid as the primary means for volume expansion for traumatic hemorrhagic shock. Predicting which patient will require DCR by prompt and accurate activation of a massive transfusion protocol, however, remains a challenge.

Effect of Hypertonic Saline 5% on Early Graft Function and Urinary Interleukin 18 and Neutrophil Gelatinase-Associated Lipocalin in Deceased-Donor Kidney Transplantation

Ischemia reperfusion injury (IRI) is one of the main causes of delayed graft function (DGF) in deceased-donor kidney transplantation (DDKT). Evidences suggest that hypertonic saline (HS) has beneficial effects on IRI. The objective of the present study is to determine the effect of intraoperative HS, on graft function and urinary biomarkers of interleukin 18 (IL-18) and neutrophil gelatinase-associated lipocalin (NGAL), in patients with DDKT. The design of the study is a randomized, open-label, pilot trial in patients with DDKT. The intervention of the study is administration of 4 mL/kg HS, 5% before graft reperfusion. The primary endpoint was DGF. Fifty-eight (58) adult patients were randomized (HS, n = 32; control, n = 26). There were no significant differences between the two groups in terms of recipient, donor, and transplant characteristics. The rate of DGF was 20% in the HS group compared with 31.8% in the control group (Relative risk 0.63; 95% CI 0.23-1.67; P = 0.36). Serial serum creatinine in the first two days after surgery in addition to urine volumes during the first day after transplantation was significantly different in the HS group (P ≤ 0.05). The urinary NGAL and IL-18 were significantly lower in HS vs. control, at 24 h after transplantation (P ≤ 0.05). The frequency of adverse reactions was similar between groups. This study did not show any significant benefits from HS administration immediately before allograft reperfusion in terms of reducing DGF, serum creatinine at hospital discharge or length of hospital stay in deceased-donor kidney transplant patients.

Resuscitation Affects Microcirculatory Polymorphonuclear Leukocyte Behavior After Hemorrhagic Shock: Role of Hypertonic Saline and Pentoxifylline

We have previously shown that lung injury following fluid resuscitation either with hypertonic saline (HS) or lactated Ringer's (LR) plus pentoxifylline (PTX) attenuated acute lung injury when compared with LR resuscitation. The objective of the present study is to determine whether our previous observations are accompanied by changes in polymorphonuclear leukocyte (PMN) behavior. To study this, PMN-endothelial cell interactions, microcirculatory blood flow, lung histology, lung PMN infiltration (WIPO, Myeloperoxidase), and lung intracellular adhesion molecule-1 (ICAM-1) expression were assessed in a controlled hemorrhagic shock model followed by LR, HS, and LR+PTX resuscitation in rodents. Rats (240-300 g) were bled to a mean arterial pressure (MAP) of 35 mm Hg for 1 hr and then randomized into three groups: HS (7.5% NaCl, 4 ml/kg); LR (3× shed blood); and LR+PTX (25 mg/kg). Additionally, total shed blood was reinfused. A sham group underwent no shock and no treatment. The internal spermatic fascia was exteriorized and the microcirculation was observed by closed-circuit TV coupled to a microscope, 2 and 6 hrs after treatment. The number of leukocytes sticking to the venular endothelium was determined 2 hrs after fluid resuscitation. Microcirculatory blood flow was measured by an optical Doppler velocimeter. Lung histology and lung MPO immunostaining were assessed at 6 hrs, and lung ICAM-1 expression was determined by immunostaining at 2 hrs following fluid resuscitation. Two hours after treatment, HS (1.4 ± 0.4), LR+PTX (1.7 ± 0.3), and sham (0.4 ± 0.2) groups presented significant reductions in leukocyte adherence (cells/100 urn venule length), compared with the LR group (4.0 ± 0.9, P < 0.05). No differences were observed 6 hrs after treatment on leukocyte adherence and microcirculatory blood flow. ICAM-1 expression was significantly higher in LR- treated animals compared with the HS, LR+PTX, and sham groups (P < 0.01). PMN infiltration and overall lung injury were significantly attenuated by HS and LR+PTX. These results support earlier studies that indicated the potential application of HS and PTX in shock therapy and the increase in PMN- endothelial cell interaction and lung injury after LR resuscitation.

Haemodynamic coherence - The relevance of fluid therapy

The ultimate goal of fluid therapy is to improve the oxygenation of cells by improving the cardiac output, thus improving microcirculation by optimizing macrocirculation. This haemodynamic coherence is often altered in patients with haemorrhagic shock and sepsis. The loss of haemodynamic coherence is associated with adverse outcomes. It may be influenced by the mechanisms of the underlying disease and properties of different fluids used for resuscitation in these critically ill patients. Monitoring microcirculation and haemodynamic coherence may be an additional tool to predict the response to fluid administration. In addition, microcirculatory analysis may support the clinician in his decision to not administer fluids when microcirculatory blood flow is preserved. In future, the indication, guidance and termination of fluid therapy may be assessed by bedside microvascular analysis in combination with standard haemodynamic monitoring.

Iso-osmolar prehydration shifts the cytokine response towards a more anti-inflammatory balance in human endotoxemia

Clinical experience suggests that the administration of fluids in human endotoxemia reduces symptoms. In the present study, the effects of a standardised fluid protocol on symptoms, inflammatory and hemodynamic parameters in human endotoxemia are determined. With approval of the local ethics committee, 16 healthy volunteers received 2 ng/kg of Escherichia coli endotoxin (O:113). After an overnight fast, nine subjects received 1.5 l of 2.5% glucose/0.45% NaCl the hour prior to the endotoxin administration and 150 ml/h during the course of the experiment (`prehydrated group'). Seven subjects only received a continuous infusion of 75 ml/h during the experiment (`non-prehydrated group'). The course of inflammatory parameters and symptoms were determined and mean arterial pressure, heart rate and forearm blood flow were measured. In the prehydrated group, TNF-α increased to 522 ± 63 pg/ml (mean ± SEM) while the maximum in the non-prehydrated group was 927 ± 187 pg/ml ( P < 0.04). IL-10 increased similarly in both groups (non-prehydrated 117 ± 18 pg/ml and prehydrated 99 ± 18 pg/ml; P = NS). The prehydrated group had a significantly lower ( P < 0.004) symptom score and recovered sooner ( P = 0.004). Endotoxin-induced changes in hemodynamics revealed no significant differences between groups. We demonstrate that prehydration in experimental human endotoxemia significantly shifts the cytokine balance towards a more anti-inflammatory pattern. This effect is associated with a reduction in symptoms, whereas the changes in hemodynamic parameters are not influenced by prehydration.

The role of hypertonic saline dextran in trauma resuscitation

Modern trauma management has recognized the importance of using conservative fluid resuscitation regimes in order to prevent complications from fluid overload arising. Hypertonic/hyperoncotic fluids appear to provide an ideal means of facilitating this, requiring only small volumes to rapidly elevate blood pressure. Hypertonic saline dextran (HSD) was introduced in 1985 but its take up has been slow, a large part of this has been due to the lack of human trials and concerns about complications.

The current evidence has been reviewed and it is clear that HSD is an efficient means of correcting hypotension, doing so mainly by the mobilizing endogenous water. It is becoming apparent that early administration has the potential to modulate the inflammatory cascade in patients at risk of developing adult respiratory distress syndrome (ARDS) and multiorgan failure. This is reflected in the handful of human trials that show a trend towards increased survival (particularly for head injuries) and a possible reduction in ARDS. The side effect profile appears to be good, even in the presence of dehydration or penetrating trauma.

Published human trials have methodological problems and lack of power of study this has led to a reliance on animal studies. Clearly there is great potential, but before large-scale prehospital usage can be justified further well-conducted randomized human trials are needed.

Microcirculatory alterations during haemorrhagic shock and after resuscitation in a paediatric animal model

BACKGROUND

Haemorrhagic shock is frequent in paediatric trauma patients and after cardiac surgery, especially after cardiopulmonary bypass. It has demonstrated to be related to bad outcome.

OBJECTIVES

To evaluate changes on microcirculatory parameters during haemorrhagic shock and resuscitation in a paediatric animal model. To determine correlation between microcirculatory parameters and other variables routinely used in the monitoring of haemorrhagic shock.

METHODS

Experimental study on 17 Maryland pigs. Thirty minutes after haemorrhagic shock induction by controlled bleed animals were randomly assigned to three treatment groups receiving 0.9% normal saline, 5% albumin with 3% hypertonic saline, or 5% albumin with 3% hypertonic saline plus a bolus of terlipressin. Changes on microcirculation (perfused vessel density (PVD), microvascular blood flow (MFI) and heterogeneity index (HI)) were evaluated and compared with changes on macrocirculation and tisular perfusion parameters.

RESULTS

Shock altered microcirculation: PVD decreased from 13.5 to 12.3 mm mm(-2) (p=0.05), MFI decreased from 2.7 to 1.9 (p<0.001) and HI increased from 0.2 to 0.5 (p<0.001). After treatment, microcirculatory parameters returned to baseline (PVD 13.6 mm mm(-2) (p<0.05), MFI 2.6 (p<0.001) and HI 0.3 (p<0.05)). Microcirculatory parameters showed moderate correlation with other parameters of tissue perfusion. There were no differences between treatments.

CONCLUSIONS

Haemorrhagic shock causes important microcirculatory alterations, which are reversed after treatment. Microcirculation should be assessed during haemorrhagic shock providing additional information to guide resuscitation.

Immunomodulatory effect of hypertonic saline in hemorrhagic shock

Multiple organ dysfunction syndrome (MODS) and nosocomial infection following trauma-hemorrhage are among the most important causes of mortality in hemorrhagic shock patients. Dysregulation of the immune system plays a central role in MODS and a fluid having an immunomodulatory effect could be advantageous in hemorrhagic shock resuscitation. Hypertonic saline (HS) is widely used as a resuscitation fluid in trauma-hemorrhagic patients. Besides having beneficial effects on the hemodynamic parameters, HS has modulatory effects on various functions of immune cells such as degranulation, adhesion molecules and cytokines expression, as well as reactive oxygen species production. This article reviews clinical evidence for decreased organ failure and mortality in hemorrhagic shock patients resuscitated with HS. Despite promising results in animal models, results from pre-hospital and emergency department administration in human studies did not show improvement in survival, organ failure, or a reduction in nosocomial infection by HS resuscitation. Further post hoc analysis showed some benefit from HS resuscitation for severely-injured patients, those who received more than ten units of blood by transfusion, patients who underwent surgery, and victims of traumatic brain injury. Several reasons are suggested to explain the differences between clinical and animal models.

Effect of hypertonic saline treatment on the inflammatory response after hydrochloric acid-induced lung injury in pigs

OBJECTIVES

Hypertonic saline has been proposed to modulate the inflammatory cascade in certain experimental conditions, including pulmonary inflammation caused by inhaled gastric contents. The present study aimed to assess the potential anti-inflammatory effects of administering a single intravenous dose of 7.5% hypertonic saline in an experimental model of acute lung injury induced by hydrochloric acid.

METHODS

Thirty-two pigs were anesthetized and randomly allocated into the following four groups: Sham, which received anesthesia and were observed; HS, which received intravenous 7.5% hypertonic saline solution (4 ml/kg); acute lung injury, which were subjected to acute lung injury with intratracheal hydrochloric acid; and acute lung injury + hypertonic saline, which were subjected to acute lung injury with hydrochloric acid and treated with hypertonic saline. Hemodynamic and ventilatory parameters were recorded over four hours. Subsequently, bronchoalveolar lavage samples were collected at the end of the observation period to measure cytokine levels using an oxidative burst analysis, and lung tissue was collected for a histological analysis.

RESULTS

Hydrochloric acid instillation caused marked changes in respiratory mechanics as well as blood gas and lung parenchyma parameters. Despite the absence of a significant difference between the acute lung injury and acute lung injury + hypertonic saline groups, the acute lung injury animals presented higher neutrophil and tumor necrosis factor alpha (TNF-α), interleukin (IL)-6 and IL-8 levels in the bronchoalveolar lavage analysis. The histopathological analysis revealed pulmonary edema, congestion and alveolar collapse in both groups; however, the differences between groups were not significant. Despite the lower cytokine and neutrophil levels observed in the acute lung injury + hypertonic saline group, significant differences were not observed among the treated and non-treated groups.

CONCLUSIONS

Hypertonic saline infusion after intratracheal hydrochloric acid instillation does not have an effect on inflammatory biomarkers or respiratory gas exchange.

Hypertonic saline for the treatment of intracranial hypertension

Intracranial hypertension is caused by brain edema generated by different disorders, the commonest of which is traumatic brain injury. The treatment of brain edema focuses on drawing water out of brain tissue into the intravascular space. This is typically accomplished with osmolar therapy, most commonly mannitol and hypertonic saline. Recent human trials suggest that hypertonic saline may have a more profound and long-lasting effect in reducing intracranial hypertension following traumatic brain injury when compared with mannitol. However, reports suffer from inconsistencies in dose, frequency, concentration, and route of administration. Side effect profile, potential complications, and contraindications to administration need to be factored in when considering which first-line osmotherapy to choose for a given patient with head injury.

Critical Care for the Patient With Multiple Trauma

Trauma remains the leading cause of death worldwide and the leading cause of death in those less than 44 years old in the United States. Admission to a verified trauma center has been shown to decrease mortality following a major injury. This decrease in mortality has been a direct result of improvements in the initial evaluation and resuscitation from injury as well as continued advances in critical care. As such, it is vital that intensive care practitioners be familiar with various types of injuries and their associated treatment strategies as well as their potential complications in order to minimize the morbidity and mortality frequently seen in this patient population.

In vivo leukocyte-mediated brain microcirculatory inflammation: a comparison of osmotherapies and progesterone in severe traumatic brain injury

BACKGROUND

Mannitol, hypertonic saline, and progesterone may blunt leukocyte recruitment after traumatic brain injury (TBI). We hypothesized that progesterone reduces pericontusional recruitment of leukocytes to a greater extent than either osmotherapy a day after TBI.

METHODS

CD1 mice underwent controlled cortical impact and were treated with osmotherapy (mannitol and hypertonic saline) or progesterone. Thirty-two hours after TBI, live pial microscopy was used to evaluate leukocyte-endothelial interactions and immunohistochemistry was used for the detection of pericontusional tissue polymorphonuclear neutrophils. Neurologic recovery was assessed before sacrifice.

RESULTS

Mannitol resulted in the lowest in vivo leukocyte recruitment compared with progesterone (795 ± 282 vs 1,636 ± 434 LEU/100 μm/minutes, P < .05). Mannitol also displayed lower tissue accumulation of leukocytes as compared with progesterone (5.7 ± 1.7 vs 15.2 ± .1 LEU/mm(2), P = .03). However, progesterone resulted in better neurologic recovery than either osmotherapy.

CONCLUSIONS

Leukocyte recruitment to injured brain is lowest with mannitol administration. How different agents alter progression of secondary brain injury will require further evaluation in humans.

Hypertonic HBOC-201 decreases neutrophil activation after hemorrhagic shock

OBJECTIVE

To evaluate neutrophil activation after exposure to standard HBC-201 (suspended in lactate Ringer's solution) versus HBOC-201 suspended in hypertonic 7.5% saline solution.

METHODS

We use plasma and tissue obtained from pigs subjected to controlled hemorrhagic shock and an ex vivo model of stimulated human whole blood. The pigs were resuscitated with the following (n = 8 per group) standard HBOC-201, or hypertonic HBOC-201. We used HTS 7.5%, Ringer's lactate as control resuscitation. Human blood was stimulated with same fluids. We measured the following neutrophil markers; IL-8, H2O2 in pig plasma, MPO in pig tissue, and H2O2, IL-8, and CD11b/CD18 in human whole blood.

RESULTS

H2O2 and IL-8 as well as tissue MPO were significantly decreased in pigs resuscitated with HT-HBOC-201 and HT 7.5%. Ex vivo experiments blood diluted with HTS and HT-HBOC-201 revealed lower expression of CD11b/CD18, H2O2, and IL-8. Blood diluted with HBOC-201 had a higher CD11b/CD18 expression than blood diluted with LR solution.

CONCLUSION

Our in vivo and ex vivo experiments indicate that HBOC-201 suspended in hypertonic 7.5% saline solution is associated with significantly less neutrophil activation when compared to standard HBOC-201 suspended in lactate Ringer's solution.

Synergistic deleterious effect of hypoxemia and hypovolemia on microcirculation in intestinal villi*

OBJECTIVE

To investigate the effect of hypoxemia, hemorrhagic shock, and the association of both of these on intestinal microcirculation (microcirculatory perfusion and leukocytes-endothelium interactions in postcapillary venules), as it can be encountered in hemorrhagic shock following trauma.

DESIGN

Prospective controlled experimental study.

SETTING

University research laboratory.

SUBJECTS

Forty-eight anesthetized and mechanically ventilated Balb/c mice.

INTERVENTION

Mice were randomly assigned to hypoxemia group in which we decreased inspired oxygen fraction during 60 minutes to reach a PaO2 of 40 mm Hg, hemorrhagic shock group in which animals were exsanguinated to a mean arterial pressure level of 40 mm Hg during 30 minutes, hypoxemia-hemorrhagic shock group in which PaO2 was decreased to 40 mm Hg during 60 minutes with exsanguination from the 30th to the 60th minute to a mean arterial pressure level of 40 mm Hg; or control group.

MEASUREMENTS AND MAIN RESULTS

Hypoxemia decreased RBCs velocity in intestinal villi but did not alter the fraction of perfused villi. Hypoxemia also triggered leukocytes adhesion to the venular endothelium. Hemorrhagic shock not only decreased RBCs velocity in villi but also slightly altered the fraction of perfused villi (94% ± 2% in hemorrhagic shock group vs 100% ± 0% in control group, p < 0.005). Furthermore, hemorrhagic shock triggered leukocytes adhesion to the venular endothelium to the same extent as hypoxemia. When hypoxemia was associated to hemorrhagic shock, it decreased villous RBCs velocity in an additive manner and the fraction of perfused villi dropped in a synergistic manner (69% ± 3% in hypoxemia-hemorrhagic shock group vs 94 ± 2 in hemorrhagic shock group, p < 0.005). The association of hypoxemia and hemorrhagic shock did not further amplify leukocytes adhesion to intestinal venules compared with either hypoxemia or hemorrhagic shock alone.

CONCLUSIONS

During hemorrhagic shock, the occurrence of hypoxemia considerably alters villous intestinal perfusion as it decreases the fraction of perfused villi in a synergistic manner, thereby increasing the risk of villous ischemia. The association of hypoxemia and hemorrhagic shock did not amplify leukocytes adhesion to the endothelium further than either hemorrhagic shock or hypoxemia alone did. As hypoxemia frequently occurs simultaneously with hemorrhagic shock in traumatic conditions, it can worsen gut ischemia leading to the exacerbation of multiple organ failure syndrome.

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.

Effects of small-volume hypertonic saline on acid-base and electrolytes balance in rats with peritonitis-induced sepsis

Our previous study has demonstrated that hypertonic saline (HS) given at 3 h after cecal ligation and puncture (CLP) surgery alleviates circulatory failure, multiple organ dysfunction syndrome, and mortality rate in rats. However, only few data exist on the application of HS in acid-base and electrolyte imbalance of sepsis. In addition, early one-dose HS administration seems to have only modest improvement on mortality rate. Thus, we evaluated the effects of HS on acid-base equilibrium and electrolyte balance in CLP-induced sepsis model and further compared with the effects of two- and one-dose HS administration. Male Wistar rats received CLP or sham operation followed by the administration of saline or HS (7.5% NaCl, 4 mL/kg, intravenously at 3 and 9 h after laparotomy or CLP). The changes in hemodynamics, biochemical variables, blood gas, electrolytes, organ histology, and plasma levels of nitric oxide (NO) and interleukin 1β (IL-1β) were examined during the 18-h observation. Hypertonic saline given either at 3 h (one-dose administration) or at 3 and 9 h (two-dose administration) after CLP attenuated circulatory failure, multiple organ dysfunction syndrome, metabolic acidosis, hyperkalemia, neutrophil infiltration, and 18-h mortality. Moreover, both one- and two-dose HS administrations significantly diminished plasma NO and IL-1β levels in CLP rats. However, only the two-dose HS administration significantly improved hyponatremia and hypocalcemia in septic rats. Beneficial effects of HS in septic rats may be attributed to not only reducing plasma levels of NO and IL-1β, but also improving metabolic acidosis and electrolyte imbalance. In addition, two-dose HS administration could reverse electrolyte imbalance caused by CLP.

Hypertonic saline reduces vascular leakage in a mouse model of severe dengue

Dengue (DEN) is a mosquito-borne viral disease and represents a serious public health threat and an economical burden throughout the tropics. Dengue clinical manifestations range from mild acute febrile illness to severe DEN hemorrhagic fever/DEN shock syndrome (DHF/DSS). Currently, resuscitation with large volumes of isotonic fluid remains the gold standard of care for DEN patients who develop vascular leakage and shock. Here, we investigated the ability of small volume of hypertonic saline (HTS) suspensions to control vascular permeability in a mouse model of severe DEN associated with vascular leakage. Several HTS treatment regimens were considered and our results indicated that a single bolus of 7.5% NaCl at 4 mL per kg of body weight administered at the onset of detectable vascular leakage rapidly and significantly reduced vascular leak for several days after injection. This transient reduction of vascular leakage correlated with reduced intestine and liver damage with restoration of the hepatic functions, and resulted in delayed death of the infected animals. Mechanistically, we showed that HTS did not directly impact on the viral titers but resulted in lower immune cells counts and decreased systemic levels of soluble mediators involved in vascular permeability. In addition, we demonstrated that neutrophils do not play a critical role in DEN-associated vascular leakage and that the therapeutic effect of HTS is not mediated by its impact on the neutrophil counts. Together our data indicate that HTS treatment can transiently but rapidly reduce dengue-associated vascular leakage, and support the findings of a recent clinical trial which evaluated the efficacy of a hypertonic suspension to impact on vascular permeability in DSS children.

Nebulized hypertonic saline attenuates acute lung injury following trauma and hemorrhagic shock via inhibition of matrix metalloproteinase-13

OBJECTIVE

We hypothesized that aerosolized inhaled hypertonic saline given at the onset of resuscitation will decrease acute lung injury following hemorrhagic shock, by inhibiting the release of epithelial derived proinflammatory mediators.

DESIGN

Animal study.

SETTING

Animal-care facility procedure room in a medical center.

SUBJECTS

Adult male Sprague-Dawley rats.

INTERVENTIONS

Rats underwent hemorrhagic shock followed by 2 hrs of resuscitation and 1 hr of observation. In the study group, nebulized hypertonic saline was delivered at the end of the shock period and after 1 hr and 2 hrs of resuscitation.

MEASUREMENTS AND MAIN RESULTS

Shock provoked acute lung injury, which was attenuated with inhaled hypertonic saline (1.56 ± 0.2 mg protein/mL vs. 0.95 ± 0.3 mg protein/mL bronchoalveolar lavage fluid, shock vs. shock + hypertonic saline, p < .01). Nebulized hypertonic saline reduced inflammation (cytokine-induced neutrophil chemoattractant-1 accumulation in bronchoalveolar lavage fluid 5999 ± 1267 pg/mL vs. 3342 ± 859 pg/mL, shock vs. shock + hypertonic saline, p = .006). Additionally, nebulized hypertonic saline inhibited matrix -metalloproteinase-13 accumulation in the bronchoalveolar lavage fluid (1513 ± 337 pg/mL bronchoalveolar lavage fluid vs. 230 ± 19 pg/mL, shock vs. shock + hypertonic saline, p = .009) and pretreatment with a matrix metalloproteinase-13 inhibitor was sufficient to attenuate postshock acute lung injury (1.42 ± 0.09 mg/mL vs. 0.77 ± 0.23 mg/mL bronchoalveolar lavage protein, shock vs. shock + matrix metalloproteinase-13 inhibitor CL-82198, p = .002).

CONCLUSION

Inhaled hypertonic saline attenuates postshock acute lung injury by exerting an anti-inflammatory effect on the pulmonary epithelium, suggesting a new clinical strategy to treat acute lung injury/acute respiratory distress syndrome.

Similar effects of hypertonic saline and mannitol on the inflammation of the blood-brain barrier microcirculation after brain injury in a mouse model

BACKGROUND

There has been substantial debate regarding the efficacy of hypertonic saline (HTS) versus mannitol (MTL) in treating moderate and severe traumatic brain injury (TBI). HTS blunts polymorphonuclear neutrophil (PMN) and endothelial cell (EC) activation and reduces tissue edema after resuscitated shock in systemic microvascular beds. MTL also modulates PMN activation markers. It remains unknown if either of these osmotherapies exert similar anti-inflammatory effects along the blood-brain barrier (BBB). We hypothesized that HTS, as compared with MTL, would more greatly reduce PMN-EC interactions, thereby reducing BBB permeability and tissue edema after simulated TBI.

METHODS

CD1 male mice (25-30 g) underwent craniotomy and window placement for observation of in vivo PMN-EC interactions in pial venules using intravital video microscopy. TBI was simulated through local suffusion of the brain surface with interleukin 1β (100 ng/0.1 mL). Animals were randomized to receive a single, equiosmolar, intravenous dose of 20% MTL or 5% HTS after injury. Live microcirculatory footage was obtained every 15 minutes for 2 hours, after which fluorescent-labeled albumin was administered to assess microvascular permeability. PMN rolling and adhesion and macromolecular leakage were analyzed offline by a blinded observer and postmortem brain and lung edema assessed by wet-to-dry ratios. Student's t test and Mann-Whitney U test determined significance (p ≤ 0.05).

RESULTS

Neither osmotherapy resulted in significant differences in PMN rolling or adhesion; however, both trended higher in HTS. Similarly, vessel permeability did not differ between groups but also trended higher with HTS. In contrast, brain and lung edema was greater in MTL than HTS as compared with controls (p = 0.05).

CONCLUSION

MTL and HTS have indistinguishable effects on PMN-EC interactions in the brain after simulated TBI. Additional studies are needed to determine if either osmotherapy has more subtle effects on BBB PMN-EC interactions after injury exerting a potential clinical advantage.

NaCl potentiates human fibrocyte differentiation

Excessive NaCl intake is associated with a variety of fibrosing diseases such as renal and cardiac fibrosis. This association has been attributed to increased blood pressure as the result of high NaCl intake. However, studies in patients with high NaCl intake and fibrosis reveal a connection between NaCl intake and fibrosis that is independent of blood pressure. We find that increasing the extracellular concentration of NaCl to levels that may occur in human blood after high-salt intake can potentiate, in serum-free culture conditions, the differentiation of freshly-isolated human monocytes into fibroblast-like cells called fibrocytes. NaCl affects the monocytes directly during their adhesion. Potassium chloride and sodium nitrate also potentiate fibrocyte differentiation. The plasma protein Serum Amyloid P (SAP) inhibits fibrocyte differentiation. High levels of extracellular NaCl change the SAP Hill coefficient from 1.7 to 0.8, and cause a four-fold increase in the concentration of SAP needed to inhibit fibrocyte differentiation by 95%. Together, our data suggest that NaCl potentiates fibrocyte differentiation. NaCl-increased fibrocyte differentiation may thus contribute to NaCl-increased renal and cardiac fibrosis.

The effectiveness of hypertonic saline and pentoxifylline (HTS-PTX) resuscitation in haemorrhagic shock and sepsis tissue injury: comparison with LR, HES, and LR-PTX treatments

PURPOSE

To compare lung and liver injury and laboratory results in haemorrhagic shock and sepsis models treated with combinations of lactated Ringer's solution (LR), 7.5% hypertonic saline (HTS), hydroxyethyl starch (HES), and pentoxifylline (PTX).

METHODS

Male Sprague-Dawley rats (200-290 g) were assigned randomly to one of four treatment groups (n=16 per group): (1) LR; (2) HES; (3) LR-PTX; and (4) HTS-PTX. Each group was subdivided into (1) haemorrhagic shock (n=8) and (2) sepsis (n=8) model groups. A venous catheter was used to inject resuscitation fluids, and an arterial catheter was used to withdraw blood and monitor mean arterial pressure (MAP). Lung and liver histology, bronchoalveolar lavage (BAL) fluid, and cytokine levels were evaluated.

RESULTS

The mean lung injury score was 1.7. At 24h after treatment, the total leucocyte count in the BAL fluid was significantly (p<0.05) higher with LR treatment (10 × 10(6) ± 0.8) than with other treatments in the sepsis model groups (HES, 6 × 10(6) ± 1.2; LR-PTX, 5 × 10(6) ± 1.5; HTS-PTX, 5 × 10(6) ± 0.6). The higher total leucocyte count after LR treatment was attributable to a greater increase in the number of neutrophils (17 ± 1.5%) compared with increases after the other treatments (HES, 6 ± 0.8%; LR-PTX, 10 ± 1.3%; HTS-PTX, 5 ± 0.4%). In the sepsis model groups, the total hepatic injury score was also significantly (p<0.05) higher with LR treatment (9.9 ± 0.5) than with the other treatments (HES, 6.7 ± 0.8; LR-PTX, 5.6 ± 0.7; HTS-PTX, 3.1 ± 0.9). This also occurred in the shock model (LR, 10.6 ± 2.1; HES, 5.8 ± 0.9; LR-PTX, 7.3 ± 0.9; HTS-PTX, 3.5 ± 0.9). As compared with LR treatment, HTS-PTX resuscitation resulted in a 49% decrease in TNF-α, 29% decrease in IL-1β, and 58% decrease in IL-6 in the shock model at 24h (p<0.05), and the respective decreases were 45, 24, and 35% in the sepsis model (p<0.05).

CONCLUSION

HTS-PTX was superior to HES, LR-PTX, and LR for treating shock and sepsis, and LR-PTX and HES gave better results than LR therapy alone.

Small-volume hypertonic saline/pentastarch improves ileal mucosal microcirculation in experimental peritonitis

We compared the effects of hypertonic saline 7.2%/6% hydroxyethyl starch (HSS-HES) and isotonic saline 0.9%/6% hydroxyethyl starch (ISS-HES) on ileal microcirculatory blood flow (MBF) at the initial phase of septic shock. Pigs were anesthetized and mechanically ventilated. Catheters were inserted into right atrium, pulmonary artery, carotid artery, and portal vein for hemodynamic measurements and for blood sampling. Ileal mucosal and muscularis MBF was continuously measured by laser Doppler flowmetry (LDF). Septic shock was obtained 240 min after induction of fecal peritonitis; then animals were randomized to receive 10 mL.kg(-1) during 10 min of either HSS-HES or ISS-HES. Systemic and microcirculatory blood flow as well as systemic metabolism were assessed. Fecal peritonitis promoted a hypodynamic septic shock, with significant reduction of mean arterial pressure (MAP) and cardiac index (CI). Ileal mucosal MBF (-34%) and ileal muscularis MBF (-54%) significantly diminished from baseline. Contrary to ISS-HES group, mucosal MBF significantly augmented after HSS-HES (+192% at min 150 post-shock) despite low blood pressure. There was weak correlation with CI (r(2)= 0.2, P=0.01) . Muscularis MBF didn't change. HSS-HES-treated animals had a significantly higher osmolarity and sodium concentration than ISS-HES group. Other variables did not change. Small-volume resuscitation with HSS-HES, but not ISS-HES, improved ileal microcirculatory impairment in experimental peritonitis model of septic shock even when MAP was low. This beneficial microcirculatory effect could be valuable in the management of early severe sepsis.

Beneficial effect of hypertonic saline resuscitation in a porcine model of severe acute pancreatitis

OBJECTIVE

Hypertonic saline (HTS) solution resuscitation has been used in a variety of clinical settings. The aim of this study was to assess the effect of HTS resuscitation on hemodynamics, systemic oxygenation, and organ damage in a porcine model of severe acute pancreatitis.

METHODS

Eighteen anesthetized and mechanically ventilated pigs were divided into 3 groups: HTS group, lactated Ringer solution (LR) group, and sham-operated group. Severe acute pancreatitis was induced in the first 2 groups by injecting 5% sodium taurocholate into the pancreatic duct, and the investigation period was 12 hours. Hemodynamic parameters, urine output, oxygenation parameters, and serum parameters were recorded consecutively. Finally, histologic examinations of the kidney, intestine, pancreas, and lung were performed.

RESULTS

In the HTS group, cardiac output decreased less significantly compared with the LR group. Furthermore, aspartate aminotransferase, creatinine, and lactate levels increased significantly in all animals with severe acute pancreatitis, but the increasing tendency was slower in the HTS group. Nevertheless, the histopathologic analysis revealed similar injuries of the kidney, intestine, pancreas, and lung between the HTS and LR groups.

CONCLUSIONS

Early administration of HTS generally improves hemodynamics and peripheral oxygenation. Despite these normalized parameters, organ damage could not be diminished to a significant degree during observation.

The effects of hypertonic fluid administration on the gene expression of inflammatory mediators in circulating leucocytes in patients with septic shock: a preliminary study

Objective

This study was designed to investigate the effect of hypertonic fluid administration on inflammatory mediator gene expression in patients with septic shock.

Design and setting

Prospective, randomized, controlled, double-blind clinical study in a 15-bed mixed intensive care unit in a tertiary referral teaching hospital.

Interventions

Twenty-four patients, who met standard criteria for septic shock, were randomized to receive a bolus of hypertonic fluid (HT, 250 ml 6% HES/7.2% NaCl) or isotonic fluid (IT, 500 ml 6% HES/0.9% NaCl) administered over 15 minutes. Randomization and study fluid administration was within 24 hours of ICU admission for all patients. This trial is registered with ANZCTR.org.au as ACTRN12607000259448.

Results

Blood samples were taken immediately before and 4, 8, 12, and 24 hours after fluid administration. Real-time reverse transcriptase polymerase chain reaction (RT rtPCR) was used to quantify mRNA expression of different inflammatory mediators in peripheral leukocytes. In the HT group, compared with the IT group, levels of gene expression of MMP9 and L-selectin were significantly suppressed (p = 0.0002 and p = 0.007, respectively), and CD11b gene expression tended to be elevated (p = NS). No differences were found in the other mediators examined.

Conclusions

In septic shock patients, hypertonic fluid administration compared with isotonic fluid may modulate expression of genes that are implicated in leukocyte-endothelial interaction and capillary leakage.

The study was performed at the Intensive Care Department, Waikato Hospital, and at the Molecular Genetics Laboratory, University of Waikato, Hamilton, New Zealand.

Trial registration

Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12607000259448

Hypertonic saline resuscitation of hemorrhagic shock does not decrease in vivo neutrophil interactions with endothelium in the blood-brain microcirculation

BACKGROUND

Resuscitation of hemorrhagic shock with isotonic crystalloids has been shown to activate polymorphonuclear neutrophils (PMNs). Although hypertonic saline (HTS) can reduce PMN activation and interactions with endothelial cells (EC) in systemic microvascular beds, no data exist demonstrating that the same occurs in the unique blood-brain barrier microcirculation. We hypothesized that resuscitation of hemorrhagic shock with HTS would blunt brain in vivo PMN-EC interactions.

METHODS

Wistar rats (250-350 g) underwent craniotomy and placement of a window for live intravital viewing of pial vessels. Twenty animals were bled to a mean arterial pressure of 30 mm Hg to 35 mm Hg for 1 hour and resuscitated with shed blood and either 5% HTS (6 mL/kg) or Ringer's lactate (RL) (2× shed blood volume). Circulating rhodamine-6G-labeled PMN in pial venules were captured by videomicroscopy at baseline (preshock), end of the shock period, after resuscitation, and every 15 minutes to 30 minutes for 2 hours. Hemodynamics and arterial gases were monitored. Off-line footage analysis allowed comparisons of PMN-EC interactions between groups.

RESULTS

Animals in both groups developed significant metabolic acidosis (p < 0.01) after hemorrhage, but postresuscitation blood pressures were similar at all time points. Crystalloid resuscitation volumes were 10× greater in RL than HTS animals (p < 0.001). For all time points, we did not observe the expected reduction in PMN rolling and adhesion in HTS animals, instead noted trends of consistently lower interactions in RL counterparts.

CONCLUSIONS

In contradistinction to studies evaluating the systemic microcirculation, HTS may activate PMN-EC crosstalk in the blood-brain microcirculation. Further studies are needed to analyze whether this effect is due to the unique nature of the blood-brain interface.

Impact of hypertonic saline on the release of selected cytokines after stimulation with LPS or peptidoglycan in ex vivo whole blood from healthy humans

The question of specific immunomodulating qualities of hypertonic saline (HTS) has not been settled. It has proven difficult to distinguish between immunomodulation directly attributable to HTS and influence because of favorable circulatory effects. The nature of immune activator may also play a role. In a whole-blood model, we have investigated these relations further, with special emphasize on osmolalities usually found after recommended dosing. Blood from 10 healthy donors was exposed to osmolalities ranging from 295 to 480 mOsm/kg and stimulated with the two clinically relevant stimulators peptidoglycan (1 µg/mL) or LPS (10 ng/mL) for 6 h at 37°C. Leukocyte response was evaluated by measuring selected cytokines in the supernatant. Moderate hyperosmolality alone boosted the release of CXCL8/IL-8. The peptidoglycan-stimulated synthesis of pivotal proinflammatory cytokines was inhibited in an osmolality-dependent way, but statistically significant only at osmolalities above those attained after routine use of HTS, i.e., 310 mOsm/kg or greater: IL-6 (P < 0.05 at 315 mOsm/kg), IL-1ß, and TNF-α (P < 0.05 at 335 mOsm/kg). Similar effects were seen for the chemokine CCL3 and the anti-inflammatory cytokine IL-10. In contrast, the effects in cells stimulated with LPS were either lower or absent. Thus, osmolalities usually found after clinical use of HTS only modestly influenced the selected immune parameters, regardless of stimulator.