Hypertonic saline resuscitation attenuates neutrophil lung sequestration and transmigration by diminishing leukocyte-endothelial interactions in a two-hit model of hemorrhagic shock and infection

European Society of Intensive Care Medicine clinical practice guideline on fluid therapy in adult critically ill patients. Part 1: the choice of resuscitation fluids

PURPOSE

This is the first of three parts of the clinical practice guideline from the European Society of Intensive Care Medicine (ESICM) on resuscitation fluids in adult critically ill patients. This part addresses fluid choice and the other two will separately address fluid amount and fluid removal.

METHODS

This guideline was formulated by an international panel of clinical experts and methodologists. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology was applied to evaluate the certainty of evidence and to move from evidence to decision.

RESULTS

For volume expansion, the guideline provides conditional recommendations for using crystalloids rather than albumin in critically ill patients in general (moderate certainty of evidence), in patients with sepsis (moderate certainty of evidence), in patients with acute respiratory failure (very low certainty of evidence) and in patients in the perioperative period and patients at risk for bleeding (very low certainty of evidence). There is a conditional recommendation for using isotonic saline rather than albumin in patients with traumatic brain injury (very low certainty of evidence). There is a conditional recommendation for using albumin rather than crystalloids in patients with cirrhosis (very low certainty of evidence). The guideline provides conditional recommendations for using balanced crystalloids rather than isotonic saline in critically ill patients in general (low certainty of evidence), in patients with sepsis (low certainty of evidence) and in patients with kidney injury (very low certainty of evidence). There is a conditional recommendation for using isotonic saline rather than balanced crystalloids in patients with traumatic brain injury (very low certainty of evidence). There is a conditional recommendation for using isotonic crystalloids rather than small-volume hypertonic crystalloids in critically ill patients in general (very low certainty of evidence).

CONCLUSIONS

This guideline provides eleven recommendations to inform clinicians on resuscitation fluid choice in critically ill patients.

Admission serum sodium and osmolarity are not associated with the occurrence or outcomes of acute respiratory distress syndrome in critically ill

BACKGROUND

Previous studies suggested that hypernatremia or hyperosmolarity may have protective effects in lung injury. We hypothesized that hypernatremia and/or hyperosmolarity would prevent ARDS.

DESIGN

Retrospective cohort study of all admissions at medical, surgical, and multidisciplinary intensive care units in Mayo Clinic, Rochester from the year of 2009 to 2019. The occurrence of ARDS was identified using a validated computerized search strategy. The association between serum sodium/osmolarity and the occurrence of ARDS was analyzed using a multivariable logistic regression model. The relationship between serum sodium/osmolarity and outcomes of ARDS was analyzed using linear and logistic regression models.

RESULTS

Among 50,498 patients, the serum sodium level on admission did not have a significant association with the occurrence of ARDS, with an adjusted odds ratio of 0.95 [95% CI (0.86, 1.05)]. There was no significant association between calculated serum osmolarity and the occurrence of ARDS, with an adjusted odds ratio of 1.03 [95% CI (1.00, 1.07)]. 1560 patients developed ARDS during the ICU stay. Their serum sodium level and osmolarity level did not have a significant association with their outcomes.

CONCLUSIONS

Admission serum sodium or serum osmolarity were not associated with the occurrence or outcomes of ARDS in ICU.

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.

Hypertonic Solution in Severe COVID-19 Patient: A Potential Adjuvant Therapy

Coronavirus disease 2019 (COVID-19) features hyper-inflammation, cytokine storm, neutrophil function changes, and sodium chloride (NaCl) homeostasis disruption, while the treatment with NaCl hypertonic solutions (HS) controls electrolytic body homeostasis and cell functions. HS treatment is a simple, popular, economic, and feasible therapy to regulate leukocyte function with a robust anti-inflammatory effect in many inflammatory diseases. The purpose of this narrative review is to highlight the knowledge on the use of HS approaches against viral infection over the past years and to describe the mechanisms involved in the release of neutrophil extracellular traps (NETs) and production of cytokine in severe lung diseases, such as COVID-19. We reported the consequences of hyponatremia in COVID-19 patients, and the immunomodulatory effects of HS, either in vitro or in vivo. We also described the relationship between electrolyte disturbances and COVID-19 infection. Although there is still a lack of clinical trials, hypertonic NaCl solutions have marked effects on neutrophil function and NETs formation, emerging as a promising adjuvant therapy in COVID-19.

Hypernatremia in the intensive care unit

PURPOSE OF REVIEW

Hypernatremia is a relatively frequent electrolyte disorder seen in critically ill patients. As many as 27% of patients in intensive care units (ICUs) develop hypernatremia of variable severity during an ICU stay. Debate among specialists often ensues as to whether to correct hypernatremia or not. Some practitioners, particularly intensivists, believe that correction of hypernatremia with fluids may cause expansion of the extracellular fluid volume (ECFV) thereby worsening ventilation and impeding extubation. Other practitioners, including many nephrologists, do not expect correction of hypernatremia to lead to clinically apparent ECFV expansion, and fear other deleterious effects of hypernatremia. In this review we address the controversy regarding appropriate practice.

RECENT FINDINGS

There are no randomized, clinical trials (RCTs) to guide the administration of electrolyte-free fluid administration in hypernatremic patients. However, there are associations, demonstrated in the literature, suggesting that hypernatremia of any severity will increase the mortality and length of stay in these patients. These associations generally support the practice of correction of hypernatremia. In addition, our knowledge of the distribution of total body water influences us towards correcting hypernatremia as an appropriate therapy. We do not expect that adequate RCTs addressing this question will be performed.

SUMMARY

Allowing persistence of any degree of hypernatremia is associated with increased mortality, length of stay (LOS) and postdischarge mortality. We expect that proper use of electrolyte-free water intake will avoid adverse outcomes.

High Na+ Environments Impair Phagocyte Oxidase-Dependent Antibacterial Activity of Neutrophils

Infection and inflammation can augment local Na⁺ abundance. These increases in local Na⁺ levels boost proinflammatory and antimicrobial macrophage activity and can favor polarization of T cells towards a proinflammatory Th17 phenotype. Although neutrophils play an important role in fighting intruding invaders, the impact of increased Na⁺ on the antimicrobial activity of neutrophils remains elusive. Here we show that, in neutrophils, increases in Na⁺ (high salt, HS) impair the ability of human and murine neutrophils to eliminate Escherichia coli and Staphylococcus aureus. High salt caused reduced spontaneous movement, degranulation and impaired production of reactive oxygen species (ROS) while leaving neutrophil viability unchanged. High salt enhanced the activity of the p38 mitogen-activated protein kinase (p38/MAPK) and increased the interleukin (IL)-8 release in a p38/MAPK-dependent manner. Whereas inhibition of p38/MAPK did not result in improved neutrophil defense, pharmacological blockade of the phagocyte oxidase (PHOX) or its genetic ablation mimicked the impaired antimicrobial activity detected under high salt conditions. Stimulation of neutrophils with phorbol-12-myristate-13-acetate (PMA) overcame high salt-induced impairment in ROS production and restored antimicrobial activity of neutrophils. Hence, we conclude that high salt-impaired PHOX activity results in diminished antimicrobial activity. Our findings suggest that increases in local Na⁺ represent an ionic checkpoint that prevents excessive ROS production of neutrophils, which decreases their antimicrobial potential and could potentially curtail ROS-mediated tissue damage.

Efficiency of Hypertonic Saline in the Management of Decompensated Heart Failure: A Systematic Review and Meta-Analysis of Clinical Studies

INTRODUCTION

Acute decompensated heart failure (ADHF), with an incidence of 1-2%, is a clinical syndrome with significant morbidity and mortality despite therapeutic advancements and ongoing clinical trials. A recent therapeutic approach to patients with ADHF includes combination therapy with hypertonic saline solution (HSS) and furosemide, based on the hypothesis that resistance to loop diuretics occurs because of achievement of plateau in water and sodium excretion in patients receiving long-term loop diuretic therapy.

OBJECTIVE

Our aim was to conduct a meta-analysis to evaluate the efficiency of combination HSS plus furosemide therapy in patients with ADHF in terms of mortality, readmissions, length of hospital stay, kidney function, urine output, body weight, and B-type natriuretic peptide (BNP).

METHODS

A total of 14 studies-four observational and ten randomized studies (total 3398 patients)-were included in the meta-analysis.

RESULTS

Our results demonstrate the superiority of combination HSS plus furosemide therapy over furosemide alone in terms of kidney function preservation (mean creatinine difference - 0.33 mg/dL; P < 0.00001), improved diuresis (mean difference [MD] 581.94 mL/24 h; P < 0.00001) and natriuresis (MD 57.19; P < 0.00001), weight loss (MD 0.99 kg; P < 0.00001), duration of hospital stay (MD - 2.72 days; P < 0.00001), readmissions (relative risk 0.63; P = 0.01), and mortality (relative risk 0.55; P < 0.00001). However, no difference in BNP levels was detected (MD 19.88 pg/mL; P = 0.50).

CONCLUSION

Despite the heterogeneity and possible risk of bias among the studies, results appear promising on multiple aspects. A clear need exists for future randomized controlled trials investigating the role of combination HSS plus furosemide therapy to clarify these effects and their possible mechanisms.

Comparison of Preoperative Hypertonic Saline versus Mannitol for Intraoperative Brain Relaxation and Early Postoperative Outcome among Patients with Cerebral Low-grade Glioma: A Prospective Study

Introduction:

Hypertonic saline (HS) has an important role in the treatment of raised intracranial pressure after traumatic brain injury. This study evaluates the efficacy and safety of HS and its impact on the postoperative course of patients undergoing craniotomy for low-grade gliomas.

Materials and Methods:

Sixty patients with supratentorial low-grade glioma were enrolled. All patients were anesthetized and operated with the same team and protocol. They successively received either HS or mannitol just before surgery. The amount of brain edema was classified according to the dural tension score (I–III) just after craniotomy and before dural opening. Other intraoperative measurements (such as urine output, need, and dosage of other diuretic agents) and postoperative findings (intensive care unit [ICU] and hospital stay, corticosteroid demand, and confusion period) were also assessed. Pre- and postoperative serum S100B levels were documented in both groups.

Results:

The dural tension score was not significantly different among the two groups: severe tension in six and five patients in the mannitol and HS groups, respectively. HS group had a significantly lower amount of diuresis (609 vs. 725 ml) during surgery. Patients in the HS group had shorter ICU stay (16.3 vs. 27.9 h) and shorter duration of corticosteroid therapy after surgery (3.4 vs. 5.2 days).

Conclusion:

HS infusion just before the onset of craniotomy is at least as effective as mannitol in controlling intraoperative brain edema in patients with supratentorial glioma. Improved early postoperative course and lower degrees of S100B rise after craniotomy seen in the HS group needs to be explained in more detailed studies.

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.

Cerebral Edema and Neurological Recovery after Traumatic Brain Injury Are Worsened if Accompanied by a Concomitant Long Bone Fracture

Progression of severe traumatic brain injury (TBI) is associated with worsening cerebral inflammation, but it is unknown how a concomitant bone fracture (FX) affects this progression. Enoxaparin (ENX), a low molecular weight heparin often used for venous thromboembolic prophylaxis, decreases penumbral leukocyte (LEU) mobilization in isolated TBI and improves neurological recovery. We investigated if TBI accompanied by an FX worsens LEU-mediated cerebral inflammation and if ENX alters this process. CD1 male mice underwent controlled cortical impact (CCI) or sham craniotomy with or without an open tibial FX, and received either ENX (1 mg/kg, three times/day) or saline for 2 days following injury. Randomization defined four groups (Sham, CCI, CCI+FX, CCI+FX+ENX, n = 10/group). Two days after CCI, neurological recovery was assessed with the Garcia Neurological Test (GNT); intravital microscopy (LEU rolling and adhesion, microvascular leakage) and blood hemoglobin levels were also evaluated. Penumbral cerebral neutrophil sequestration (Ly-6G immunohistochemistry [IHC]) were evaluated post-mortem. In vivo LEU rolling was greater in CCI+FX (45.2 ± 4.8 LEUs/100 μm/min) than in CCI alone (26.5 ± 3.1, p = 0.007), and was suppressed by ENX (23.2 ± 5.5, p = 0.003 vs. CCI + FX). Neurovascular permeability was higher in CCI+FX (71.1 ± 2.9%) than CCI alone (42.5 ± 2.3, p < 0.001). GNT scores were lower in CCI+FX (15.2 ± 0.2) than in CCI alone (16.3 ± 0.3, p < 0.001). Hemoglobin was lowest in the CCI+FX+ENX group, lower than in Sham or CCI. IHC demonstrated greatest polymorphonuclear neutrophil (PMN) invasion in CCI+FX in uninjured cerebral territories. A concomitant long bone FX worsens TBI-induced cerebral LEU mobilization, microvascular leakage, and cerebral edema, and impairs neurological recovery at 48 h. ENX suppresses this progression but may increase bleeding.

Sodium lactate improves renal microvascular thrombosis compared to sodium bicarbonate and 0.9% NaCl in a porcine model of endotoxic shock: an experimental randomized open label controlled study

Background

Sodium lactate seemed to improve fluid balance and avoid fluid overload. The objective of this study was to determine if these beneficial effects can be at least partly explained by an improvement in disseminated intravascular coagulation (DIC)-associated renal microvascular thrombosis.

Methods

Ancillary work of an interventional randomized open label controlled experimental study. Fifteen female “Large White” pigs (2 months old) were challenged with intravenous infusion of E. coli endotoxin. Three groups of five animals were randomly assigned to receive different fluids: a treatment group received sodium lactate 11.2% (SL group); an isotonic control group received 0.9% NaCl (NC group); a hypertonic control group, with the same amount of osmoles and sodium than SL group, received sodium bicarbonate 8.4% (SB group). Glomerular filtration rate (GFR) markers, coagulation and inflammation parameters were measured over a 5-h period. Immediately after euthanasia, kidneys were withdrawn for histological study. Statistical analysis was performed with nonparametric tests and the Dunn correction for multiple comparisons. A p < 0.05 was considered significant.

Results

The direct immunofluorescence study revealed that the percentage of capillary sections thrombosed in glomerulus were significantly lesser in SL group [5 (0–28) %] compared to NC [64 (43–79) %, p = 0.01] and SB [64 (43–79), p = 0.03] groups. Alterations in platelet count and fibrinogen level occurred earlier and were significantly more pronounced in both control groups compared to SL group (p < 0.05 at 210 and 300 min). The increase in thrombin–antithrombin complexes was significantly higher in NC [754 (367–945) μg/mL; p = 0.03] and SB [463 (249–592) μg/mL; p = 0.03] groups than in SL group [176 (37–265) μg/mL]. At the end of the experiment, creatinine clearance was significantly higher in SL group [55.46 (30.07–67.85) mL/min] compared to NC group [1.52 (0.17–27.67) mL/min, p = 0.03].

Conclusions

In this study, we report that sodium lactate improves DIC-associated renal microvascular thrombosis and preserves GFR. These findings could at least partly explain the better fluid balance observed with sodium lactate infusion.

ICU mortality is increased with high admission serum osmolarity in all patients other than those admitted with pulmonary diseases and hypoxia

BACKGROUND AND OBJECTIVE

High serum osmolarity has been shown to be lung protective. There is lack of clinical studies evaluating the impact on outcomes such as mortality. We aimed to examine the effect of serum osmolarity on intensive care unit (ICU) mortality in critically ill patients METHODS: Data from January 2000 to December 2012 was accessed using the Australian and New Zealand Intensive Care Society (ANZICS) Clinical Outcomes and Resource Evaluation (CORE) database. A total of 509 180 patients were included. Serum osmolarity was calculated from data during the first 24 h of ICU admission. Predefined subgroups (Acute Physiology and Chronic Health Evaluation (APACHE) III diagnostic codes), including patients with acute pulmonary diagnoses, were examined. The effect of serum osmolarity on ICU mortality was assessed with analysis adjusted for illness severity (serum sodium, glucose and urea component removed) and year of admission. Results are presented as OR (95% CI) referenced against a serum osmolarity of 290-295 mmol/L.

RESULTS

The ICU mortality was elevated at each extremes of serum osmolarity (U-shaped relationship). A similar relationship was found in various subgroups, with the exception of patients with pulmonary diagnoses in whom ICU mortality was not influenced by high serum osmolarity and was different from other non-pulmonary subgroups (P < 0.01). Any adverse associations with high serum osmolarity in pulmonary patients were confined to patients with a PaO₂ /FiO₂ ratio > 200.

CONCLUSION

High admission serum osmolarity was not associated with increased odds for ICU death in pulmonary patients, unlike other subgroup of patients, and could be a potential area for future interventional therapy.

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.

Pretreatment with endothelium-derived nitric oxide synthesis modulators on gastrointestinal microcirculation during NOTES: an experimental study

BACKGROUND AND STUDY AIMS

On-demand endoscopic insufflation during natural orifice transluminal endoscopic surgery (NOTES) adversely affects microcirculatory blood flow (MBF), even with low mean intra-abdominal pressure, suggesting that shear stress caused by time-varying flow fluctuations has a great impact on microcirculation. As shear stress is inversely related to vascular diameter, nitric oxide (NO) production acts as a brake to vasoconstriction.

OBJECTIVE

To assess whether pretreatment by NO synthesis modulators protects gastrointestinal MBF during transgastric peritoneoscopy.

METHODS

Fourteen pigs submitted to cholecystectomy by endoscope CO₂ insufflation for 60 min were randomized into 2 groups: (1) 150 mg/kg of N-acetyl cysteine (NAC, n = 7) and (2) 4 ml/kg of hypertonic saline 7.5 % (HS, n = 7), and compared to a non-treated NOTES group (n = 7). Five animals made up a sham group. Colored microspheres were used to assess changes in MBF.

RESULTS

The average level of intra-abdominal pressure was similar in all groups (9 mmHg). In NOTES group microcirculation decrease compared with baseline was greater in renal cortex, mesocolon, and mesentery (41, 42, 44 %, respectively, p < 0.01) than in renal medulla, colon, and small bowel (29, 32, 34, respectively, p < 0.05). NAC avoided the peritoneoscopy effect on renal medulla and cortex (4 and 14 % decrease, respectively) and reduced the impact on colon and small bowel (20 % decrease). HS eliminated MBF changes in colon and small bowel (14 % decrease) and modulated MBF in renal medulla and cortex (19 % decrease). Neither treatment influenced mesentery MBF decrease.

CONCLUSIONS

Both pretreatments can effectively attenuate peritoneoscopy-induced deleterious effects on gastrointestinal MBF.

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.

Hypertonic sodium lactate improves fluid balance and hemodynamics in porcine endotoxic shock

Introduction

Based on the potential interest in sodium lactate as an energy substrate and resuscitative fluid, we investigated the effects of hypertonic sodium lactate in a porcine endotoxic shock.

Methods

Fifteen anesthetized, mechanically ventilated pigs were challenged with intravenous infusion of E. coli endotoxin. Three groups of five animals were randomly assigned to receive 5 mL/kg/h of different fluids: a treatment group received hypertonic sodium lactate 11.2% (HSL group); an isotonic control group receiving 0.9% NaCl (NC group); a hypertonic control group with the same amount of osmoles and sodium than HSL group receiving hypertonic sodium bicarbonate 8.4% (HSB group). Hemodynamic and oxygenation variables, urine output and fluid balance were measured at baseline and at 30, 60, 120, 210 and 300 min. Skin microvascular blood flow at rest and during reactive hyperemia was obtained using a laser Doppler flowmetry technique. Results were given as median with interquartile ranges.

Results

Endotoxin infusion resulted in hypodynamic shock. At 300 min, hemodynamics and oxygenation were significantly enhanced in HSL group: mean arterial pressure (103 [81–120] mmHg vs. 49 [41–62] in NC group vs. 71 [60–78] in HSB group), cardiac index (1.6 [1.2–1.8] L/min/m² vs. 0.9 [0.5–1.1] in NC group vs. 1.3 [0.9–1.6] in HSB group) and partial pressure of oxygen (366 [308–392] mmHg vs. 166 [130–206] in NC group vs. 277 [189–303] in HSB group). At the same time, microvascular reactivity was significantly better in HSL group with a lower venoarterial CO₂ tension difference (5.5 [4–10] mmHg vs. 17 [14–25] in NC group vs. 14 [12–15] in HSB group). The cumulative fluid balance was lower in HSL group (-325 [-655; -150] mL) compared to NC (+560 [+230; +900] mL, p = 0.008) and HSB (+185 [-110; +645] mL, p = 0.03) groups.

Conclusions

In our hypodynamic model of endotoxic shock, infusion of hypertonic sodium lactate improves hemodynamic and microvascular reactivity with a negative fluid balance and a better oxygenation.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0467-3) contains supplementary material, which is available to authorized users.

Pentoxifylline attenuates leukocyte-endothelial interactions in a two-hit model of shock and sepsis

BACKGROUND

This study investigated the effects of pentoxifylline (PTX) combined with resuscitation fluids on microcirculatory dysfunctions in a two-hit model of shock and sepsis.

MATERIALS AND METHODS

Male Wistar rats (250 g) were submitted to hemorrhagic shock and reperfusion followed by sepsis induced by cecal ligation and puncture. For the initial treatment of shock, rats were randomly divided into: sham, no injury, no treatment; hypertonic saline solution (HS) (7.5%, 4 mL/kg); lactated Ringer's solution (LR, 3 × shed blood volume); HS + PTX (4 mL/Kg + 25 mg/kg PTX); and LR + PTX (3 × shed blood volume + 25 mg/kg PTX). After 48 h of being exposed to the double injury, leukocyte-endothelial interactions were assessed by intravital microscopy of the mesentery. Endothelial expression of P-selectin and intercellular adhesion molecule-1 (ICAM-1) was evaluated by immunohistochemistry, as well as lung neutrophil infiltration by histology.

RESULTS

Lactated Ringer's solution induced marked increases (P < 0.001) in the number of rolling leukocytes per 10 min (two-fold), adherent leukocytes per 100 μm venule length (six-fold), migrated leukocytes per 5000 μm(2) (eight-fold), P-selectin and ICAM-1 expression (four-fold), and lung neutrophil infiltration (three-fold) compared with sham. In contrast, PTX attenuated leukocyte-endothelial interactions, P-selectin and ICAM-1 expression at the mesentery when associated with either LR (P < 0.001) or HS (P < 0.05). Neutrophil migration into the lungs was similarly reduced by PTX (P < 0.05).

CONCLUSIONS

Data presented showed that pentoxifylline attenuates microcirculatory disturbances at the mesenteric bed with significant minimization of lung inflammation after a double-injury model of hemorrhagic shock and reperfusion followed by sepsis.

Admission high serum sodium is not associated with increased intensive care unit mortality risk in respiratory patients

BACKGROUND

Because increased serum osmolarity may be lung protective, we hypothesized that increased mortality associated with increased serum sodium would be ameliorated in critically ill patients with an acute respiratory diagnosis.

METHODS

Data collected within the first 24 hours of intensive care unit (ICU) admission were accessed using ANZICS CORE database. From January 2000 to December 2010, 436,209 patients were assessed. Predefined subgroups including patients with acute respiratory diagnoses were examined. The effect of serum sodium on ICU mortality was assessed with analysis adjusted for illness severity and year of admission. Results are presented as odds ratio (95% confidence interval) referenced against a serum sodium range of 135 to 144.9 mmol/L.

RESULTS

Overall ICU mortality was increased at each extreme of dysnatremia (U-shaped relationship). A similar trend was found in various subgroups, with the exception of patients with respiratory diagnoses where ICU mortality was not influenced by high serum sodium (odds ratio, 1.3 [0.7-1.2]) and was different from other patient groups (P<.01). Any adverse associations with hypernatremia in respiratory patients were confined to those with arterial pressure of oxygen (PaO2)/fraction of inspired oxygen (Fio2) ratios of greater than 200.

CONCLUSION

High admission serum sodium is associated with increased odds for ICU death, except in respiratory patients.

Traumatic coagulopathy--part 2: Resuscitative strategies

OBJECTIVE

To discuss the current resuscitative strategies for trauma-induced hemorrhagic shock and acute traumatic coagulopathy (ATC).

ETIOLOGY

Hemorrhagic shock can be acutely fatal if not immediately and appropriately treated. The primary tenets of hemorrhagic shock resuscitation are to arrest hemorrhage and restore the effective circulating volume. Large volumes of isotonic crystalloids have been the resuscitative strategy of choice; however, data from experimental animal models and retrospective human analyses now recognize that large-volume fluid resuscitation in uncontrolled hemorrhage may be deleterious. The optimal resuscitative strategy has yet to be defined. In human trauma, implementing damage control resuscitation with damage control surgery for controlling ongoing hemorrhage, acidosis, and hypothermia; managing ATC; and restoring effective circulating volume is emerging as a more optimal resuscitative strategy. With hyperfibrinolysis playing an integral role in the manifestation of ATC, the use of antifibrinolytics (eg, tranexamic acid and aminocaproic acid) may also serve a beneficial role in the early posttraumatic period. Considering the sparse information regarding these resuscitative techniques in veterinary medicine, veterinarians are left with extrapolating information from human trials and experimental animal models.

DIAGNOSIS

Viscoelastic tests integrated with predictive scoring systems may prove to be the most reliable methods for early detection of ATC as well as for guiding transfusion requirements.

SUMMARY

Hemorrhage accounts for up to 40% of human trauma-related deaths and remains the leading cause of preventable death in human trauma. The exact proportion of trauma-related deaths due to exsanguinations in veterinary patients remains uncertain. Survivability depends upon achieving rapid definitive hemostasis, early attenuation of posttraumatic coagulopathy, and timely restoration of effective circulating volume. Early institution of damage control resuscitation in severely injured patients with uncontrolled hemorrhage has the ability to curtail posttraumatic coagulopathy and the exacerbation of metabolic acidosis and hypothermia and improve survival until definitive hemostasis is achieved.

The role of the microcirculation in delayed cerebral ischemia and chronic degenerative changes after subarachnoid hemorrhage

The mortality after aneurysmal subarachnoid hemorrhage (SAH) is 50%, and most survivors suffer severe functional and cognitive deficits. Half of SAH patients deteriorate 5 to 14 days after the initial bleeding, so-called delayed cerebral ischemia (DCI). Although often attributed to vasospasms, DCI may develop in the absence of angiographic vasospasms, and therapeutic reversal of angiographic vasospasms fails to improve patient outcome. The etiology of chronic neurodegenerative changes after SAH remains poorly understood. Brain oxygenation depends on both cerebral blood flow (CBF) and its microscopic distribution, the so-called capillary transit time heterogeneity (CTH). In theory, increased CTH can therefore lead to tissue hypoxia in the absence of severe CBF reductions, whereas reductions in CBF, paradoxically, improve brain oxygenation if CTH is critically elevated. We review potential sources of elevated CTH after SAH. Pericyte constrictions in relation to the initial ischemic episode and subsequent oxidative stress, nitric oxide depletion during the pericapillary clearance of oxyhemoglobin, vasogenic edema, leukocytosis, and astrocytic endfeet swelling are identified as potential sources of elevated CTH, and hence of metabolic derangement, after SAH. Irreversible changes in capillary morphology and function are predicted to contribute to long-term relative tissue hypoxia, inflammation, and neurodegeneration. We discuss diagnostic and therapeutic implications of these predictions.

The cardioprotective effect of hypertonic saline is associated with inhibitory effect on macrophage migration inhibitory factor in sepsis

Sepsis can cause myocardial dysfunction, which contributes to the high mortality of sepsis. Hypertonic saline (HS) has been reported to increase myocardial contractility in sepsis. In the present study, mechanisms of action of HS resuscitation (4 mL of 7.5% NaCl per kilogram) on cardiac function have been evaluated in septic rats. HS was administered 1 h after LPS (10 mg/kg, i.v.) challenge. The mean arterial blood pressure significantly decreased 4 h after LPS challenge, and septic shock was observed at the end of experiment (6 h). Posttreatment with HS prevented hypotension caused by LPS and significantly improved cardiac function, evidenced by increases in left ventricular developed pressure, mean +dP/dt and -dP/dt. The amplitude of electrical-stimulated intracellular Ca(2+) transient in isolated single cardiomyocytes was significantly reduced after 6 h LPS insult, which was recovered by HS. In addition, LPS resulted in significant increases in neutrophil myeloperoxidase activity, macrophage migration inhibitory factor (MIF), and NF-κB phospho-p65 protein levels in myocardium at 6 h, which were significantly attenuated by HS. In conclusion, HS improved myocardial contractility and prevented circulatory failure induced by endotoxemia, which may attribute to improvement of intracellular calcium handling process and inhibitory effects on neutrophil infiltration and MIF production in hearts.

Hyperosmolarity attenuates TNF-α-mediated proinflammatory activation of human pulmonary microvascular endothelial cells

Firm neutrophil (PMN)-endothelial (EC) adhesion is crucial to the PMN-mediated hyperinflammation observed in acute lung injury. Hypertonic saline (HTS) used for resuscitation of hemorrhagic shock has been associated with a decreased incidence of PMN-mediated lung injury/acute respiratory distress syndrome. We hypothesize that physiologically accessible hypertonic incubation (170 vs. 140 mM, osmolarity ranging from 360 to 300 mOsm/L) inhibits proinflammatory activation of human pulmonary microvascular endothelial cells (HMVECs). Proinflammatory activation of HMVECs was investigated in response to tumor necrosis factor-α (TNF-α), including interleukin 8 (IL-8) release, intercellular adhesion molecule 1 (ICAM-1) surface expression, PMN adhesion, and signaling mechanisms under both isotonic (control) and hypertonic conditions. Hyperosmolarity alone had no effect on either basal IL-8 release or ICAM-1 surface expression but did lead to concentration-dependent decreases in TNF-α-induced IL-8 release, ICAM-1 surface expression, and PMN-HMVEC adhesion. Conversely, HTS activated p38 mitogen-activated protein kinase (MAPK) and enhanced TNF-α activation of p38 MAPK. Despite this basal activation, hyperosmolar incubation attenuated TNF-α-stimulated IL-8 release and ICAM-1 surface expression and subsequent PMN adherence, while p38 MAPK inhibition did not further influence the effects of hyperosmolar conditions on ICAM-1 surface expression. In addition, TNF-α induced nuclear factor-κB DNA binding, but HTS conditions attenuated this by 31% (P < 0.01). In conclusion, HTS reduces PMN-HMVEC adhesion and TNF-α-induced proinflammatory activation of primary HMVECs via attenuation of nuclear factor-κB signaling.

Reactive oxygen species regulate context-dependent inhibition of NFAT5 target genes

The activation of nuclear factor of activated T cells 5 (NFAT5), a well-known osmoprotective factor, can be induced by isotonic stimuli, such as activated Toll-like receptors (TLRs). It is unclear, however, how NFAT5 discriminates between isotonic and hypertonic stimuli. In this study we identified a novel context-dependent suppression of NFAT5 target gene expression in RAW 264.7 macrophages stimulated with lipopolysaccharide (LPS) or a high salt (NaCl) concentration. Although LPS and NaCl both used NFAT5 as a core transcription factor, these stimuli mutually inhibited distinct sets of NFAT5 targets within the cells. Although reactive oxygen species (ROS) are essential for this inhibition, the source of ROS differed depending on the context: mitochondria for high salt and xanthine oxidase for TLRs. Specifically, the high salt-induced suppression of interleukin-6 (IL-6) production was mediated through the ROS-induced inhibition of NFAT5 binding to the IL-6 promoter. The context-dependent inhibition of NFAT5 target gene expression was also confirmed in mouse spleen and kidney tissues that were cotreated with LPS and high salt. Taken together, our data suggest that ROS function as molecular sensors to discriminate between TLR ligation and osmotic stimuli in RAW 264.7 macrophages, directing NFAT5 activity toward proinflammatory or hypertonic responses in a context-dependent manner.

Aggressive early crystalloid resuscitation adversely affects outcomes in adult blunt trauma patients: an analysis of the Glue Grant database

BACKGROUND

Evidence suggests that aggressive crystalloid resuscitation is associated with significant morbidity in various clinical settings. We wanted to assess whether aggressive early crystalloid resuscitation adversely affects outcomes in adult blunt trauma patients.

METHODS

Data were derived from the Glue Grant database. Our primary outcome measure was all-cause in-hospital mortality. Secondary outcomes included days on mechanical ventilation; intensive care unit (ICU) and hospital length of stay (LOS); inflammatory (acute lung injury and adult respiratory distress syndrome, or multiple-organ failure) and resuscitation-related morbidity (abdominal and extremity compartment syndromes or acute renal failure) and nosocomial infections (ventilator-associated pneumonia, bloodstream, urinary tract, and surgical site infections).

RESULTS

In our sample of 1,754 patients, in-hospital mortality was not affected, but ventilator days (p < 0.001) as well as ICU (p = 0.009) and hospital (p = 0.002) LOS correlated strongly with the amount of crystalloids infused in the first 24 hours after injury. Amount of crystalloid resuscitation was also associated with the development of adult respiratory distress syndrome (p < 0.001), multiple-organ failure (p < 0.001), bloodstream (p = 0.001) and surgical site infections (p < 0.001), as well as abdominal (p < 0.001) and extremity compartment syndromes (p = 0.028) in a dose-dependent fashion, when age, Glasgow Coma Scale (GCS), severity of injury and acute physiologic derangement, comorbidities, as well as colloid and blood product transfusions were controlled for.

CONCLUSION

Crystalloid resuscitation is associated with a substantial increase in morbidity, as well as ICU and hospital LOS in adult blunt trauma patients.

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.

Hyperosmolar therapy for intracranial hypertension

The use of hyperosmolar agents for intracranial hypertension was introduced in the early 20th century and remains a mainstay of therapy for patients with cerebral edema. Both animal and human studies have demonstrated the efficacy of two hyperosmolar agents, mannitol and hypertonic saline, in reducing intracranial pressure via volume redistribution, plasma expansion, rheologic modifications, and anti-inflammatory effects. However, because of physician and institutional variation in therapeutic practices, lack of standardized protocols for initiation and administration of therapy, patient heterogeneity, and a paucity of randomized controlled trials have yielded little class I evidence on which clinical decisions can be based, most current evidence regarding the use of hyperosmolar therapy is derived from retrospective analyses (class III) and case series (class IV). In this review, we summarize the available evidence regarding the use of hyperosmolar therapy with mannitol or hypertonic saline for the medical management of intracranial hypertension and present a comprehensive discussion of the evidence associated with various theoretical and practical concerns related to initiation, dosage, and monitoring of therapy.

Damage Control Immunoregulation: Is There a Role for Low-Volume Hypertonic Saline Resuscitation in Patients Managed with Damage Control Surgery?

Hypertonic saline (HTS) is beneficial in the treatment of head-injured patients as a result of its potent cytoprotective effects on various cell lines. We hypothesize that low-volume resuscitation with 3 per cent HTS, when used after damage control surgery (DCS), improves outcomes compared with standard resuscitation with isotonic crystalloid solution (ICS). This is a 4-year retrospective review from two Level I trauma centers. Patients included had 10 units or more of packed red blood cells during initial DCS. On arrival to the trauma intensive care unit (TICU), patients were resuscitated with low-volume 3 per cent HTS or with conventional ICS. A cohort analysis was performed comparing resuscitation strategies. Univariate analysis of continuous data was done with Student t test followed by multivariate analysis. Of 188 patients included, 76 were in the low-volume HTS group and 112 in the ICS group. Demographics were similar between the groups. Over the next 48 hours after DCS in HTS versus ISC groups, intravenous fluids were given: 1920 ± 455 mL versus 8400 ± 1200 mL ( P < 0.0001); urine output was 4320 ± 480 mL versus 1940 ± 480 mL( P < 0.0001); mean TICU length of stay was 10 ± 8 versus 16 ± 15 days ( P < 0.01); prevalence of acute respiratory distress syndrome was 4.0 versus 13.4 per cent ( P = 0.02); sepsis was 6.6 versus 15.2 per cent ( P = 0.06); multisystem organ failure was: 2.6 versus 16.1 per cent ( P < 0.01); and 30-day mortality was 5.3 versus 15.2 per cent ( P = 0.03). There was no difference for prevalence of renal failure at 5.3 versus 3.6 per cent ( P = 0.58). Low-volume resuscitation with HTS administered after DCS on arrival to the TICU may have a protective effect on the polytrauma patient. We believe that this study demonstrates a role for low-volume resuscitation with HTS to improve outcomes in patients undergoing DCS.

Hypertonic sodium chloride hydroxyethyl starch injection reduces histopathological changes in the intestinal mucosa of rats with hemorrhagic shock

AIM: To evaluate the effect of small-volume hypertonic sodium chloride hydroxyethyl starch injection on histopathological changes in the intestinal mucosa and plasma levels of NO in rats with hemorrhagic shock.

METHODS: Male SD rats were hemorrhaged to the mean arterial pressure of 40 mmHg ± 5 mmHg for 30 min to induce hemorrhagic shock. Animals were randomly divided into three groups: rats resuscitated with 4 mL/kg of 5.0% hypertonic sodium chloride hydroxyethyl starch injection and retransfused shed blood, those resuscitated with lactated Ringer's solution (two times the volume of shed blood) and retransfused shed blood, and those undergoing sham hemorrhage. The dynamic changes in plasma NO concentrations were monitored, and pathological changes in the small intestine were observed.

RESULTS: After resuscitation with hypertonic sodium chloride hydroxyethyl starch injection, NO showed no significant changes (P > 0.05), and pathological changes in the small intestine were significantly reduced. In contrast, plasma NO concentration significantly decreased (P < 0.05) and pathological damage to the small intestine showed no significant improvement in rats resuscitated with lactated Ringer's solution.

CONCLUSION: Resuscitation with hypertonic sodium chloride hydroxyethyl starch injection reduces intestinal damage in rats hemorrhagic shock possibly via a mechanism associated with protection of endothelial cell function.

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.

A comparison of hypertonic (7.2%) and isotonic (0.9%) saline for fluid resuscitation in horses: a randomized, double-blinded, clinical trial

BACKGROUND

Hypertonic saline solution (7.2%) (HSS) can quickly replace intravascular volume deficits. HSS more recently has been advocated in the treatment of traumatic brain injury, but its use in dehydrated patients remains controversial.

HYPOTHESIS

Hypertonic saline solution will show a significant improvement in both clinical and laboratory hydration parameters as compared to isotonic (0.9%) saline solution (ISS).

ANIMALS

Endurance horses eliminated from the 2009 Western States 100-mile (220-km) endurance ride and requiring IV fluid therapy were eligible for enrollment in the study.

METHODS

Twenty-two horses were randomly assigned to receive 4 mL/kg of either HSS or ISS along with 5 L lactated Ringer's solution (LRS). After this bolus, horses were treated with additional LRS in varying amounts. Blood and urine samples were collected before, during, and after treatment. Data were compared using 2-way ANOVA with repeated measures.

RESULTS

As compared to ISS, HSS horses showed greater decreases in PCV (P = .04), total protein (P = .01), albumin (P = .01), and globulin (P = .02) concentrations. HSS horses showed greater increases in sodium and chloride (P < .001) as compared to ISS horses. Horses receiving HSS had a shorter time to urination (P = .03) and lower specific gravity (P < .001) than those receiving ISS.

CONCLUSIONS

Results of this study indicate that HSS may provide faster restoration of intravascular volume deficits than ISS in endurance horses receiving emergency medical treatment. More marked electrolyte changes should be expected with HSS, however, and additional fluids after HSS administration likely are needed.

Use of hypertonic saline injection in trauma

PURPOSE

The use of hypertonic saline injection in trauma patients is discussed.

SUMMARY

Patients with hemorrhage, burns, and traumatic brain injury (TBI) may develop hypovolemic shock and require resuscitation. Compared with conventional isotonic crystalloids, hypertonic saline has several advantages, including hemodynamic, immune-modulating, and antiinflammatory effects, for use in trauma patients for resuscitation. In addition, hypertonic saline is also used in patients with TBI to reduce intracranial pressure (ICP). Overall, studies have not shown a difference in mortality or other clinically important outcomes with the use of hypertonic saline for resuscitation in trauma patients; however, most of these studies were not adequately powered to show significant differences. A recent Cochrane review concluded that there is no evidence that hypertonic crystalloids are better than isotonic or near-isotonic crystalloids for fluid resuscitation in trauma patients. Two recent trials that were adequately powered to investigate a mortality endpoint were halted for futility. A few small randomized controlled studies found that hypertonic saline was more effective than mannitol as a hyperosmolar agent for ICP reduction. Recent guidelines from the American Burn Association have suggested that hypertonic saline may be used for burn shock resuscitation by experienced providers with close monitoring to avoid excessive hypernatremia. One of the main concerns with the use of hypertonic saline is its potential to cause central pontine myelinolysis due to a rapid increase in serum sodium levels.

CONCLUSION

There is no evidence that hypertonic saline provides any additional benefit over isotonic crystalloid solutions for trauma resuscitation. Hypertonic saline may be more effective than mannitol at reducing ICP in patients with TBI.

Effects of different resuscitation fluids on acute lung injury in a rat model of uncontrolled hemorrhagic shock and infection

BACKGROUND

To investigate the effects of different resuscitation fluids on acute lung injury in a rat model of uncontrolled hemorrhagic shock (HS) followed by mimicked infection.

METHODS

Sixty Sprague-Dawley rats were randomly assigned to one of the five groups (n = 12 per group) to receive the following treatments: (1) control group (group C), surgery, no hemorrhage, and no resuscitation; (2) no fluid resuscitation group; (3) lactated Ringer's solution group; (4) 7.5% hypertonic saline (HTS) group; and (5) hydroxyethyl starch group (group HES). All experimental groups were subjected to three phases: phase I entailed massive hemorrhage with a mean arterial pressure of 35 mm Hg to 40 mm Hg for 60 minutes by tail amputation and followed by mimicked infection by intratracheal administration of lipopolysaccharide 2 mg/kg. The animals in each group were then partially resuscitated with the fluid assigned to the group. Phase II of 60 minutes commenced at tail ligation, involved hemostasis, and return of all the blood initially shed. Phase III was an observation phase with no any further treatment and lasted for 3.5 hours. The survival rate at the end of the phase III was recorded. After phase III, arterial blood gases were recorded. The wet to dry lung weight ratio, pulmonary microvascular permeability, the expression of transforming growth factor (TGF)-beta1, and Smad2 were determined. The lung histology was also assessed.

RESULTS

HES and HTS solutions were more effective than no fluid resuscitation and lactated Ringer's solution in reducing the detrimental effects of HS and infection on the lungs, as seen by the significantly lower pulmonary microvascular permeability and wet to dry lung weight ratio, the improved arterial blood gases and lower levels of TGF-beta1and Smad2 expression in lung tissues. These beneficial effects were most pronounced in the group HES.

CONCLUSIONS

This study demonstrated that resuscitation with HTS and especially with HES could reduce lung tissue damage and pulmonary edema after severe uncontrolled HS. The TGF-beta1/Smad2 signaling pathway might play a key role in regulation of pulmonary permeability and formation of pulmonary edema in a rat model of uncontrolled HS and infection.

Donor pretreatment with hypertonic saline attenuates primary allograft dysfunction: a pilot study in a porcine model

BACKGROUND

Hypertonic saline (HTS) has been previously demonstrated to have immune modulatory and vascular protective effects. We assessed the effect of donor pretreatment with HTS on allograft preservation in a porcine model of orthotopic heart transplantation.

METHODS AND RESULTS

Orthotopic transplants were performed after 6 hours of cold static allograft storage. Donor pigs were randomly assigned to pretreatment with (n=7) or without (n=6) HTS (4.5 mL/kg of 7.5% NaCl) administered 1 hour before donor heart arrest. Administration of HTS increased serum sodium level from 138+/-2 mmol/L to 154+/-4 mmol/L, which normalized to 144+/-3 mmol/L 1 hour after infusion. Successful weaning from cardiopulmonary bypass was significantly greater in HTS-treated hearts (6/7 vs 1/6; P=0.029). Preload recruitable stroke work after transplantation was improved compared to control (88+/-21% vs 35+/-8% of baseline; P=0.0001). Similarly, end-systolic elastance was improved compared to control (85+/-17% vs 42+/-12% of baseline; P=0.0002). Posttransplantation systolic blood pressure was significantly higher in the donor HTS group (60+/-9 mm Hg vs 35+/-6 mm Hg; P=0.04). Donor HTS treatment improved coronary artery endothelial-dependent vasorelaxation compared with control (Emax: HTS, 59+/-4%; control, 47+/-3%; P=0.04). HTS also resulted in improved endothelial-independent vasorelaxation compared with control (Emax: HTS, 71+/-3%; control, 59+/-4%; P=0.03; ED-50: HTS, 0.56x10 to 6+/-0.23 mol/L; control, 2.5x10 to 6+/-1.0 mol/L; P=0.04). Sensitivity to endothelin-1-induced vasospasm was reduced with HTS pretreatment (% maximum contraction [Cmax]: HTS, 338+/-15%; control, 419+/-40%; P=0.01).

CONCLUSIONS

Donor HTS pretreatment attenuates posttransplantation cardiac allograft myocardial dysfunction, improves posttransplantation systemic hemodynamic function, and preserves posttransplantation cardiac allograft vascular function. HTS may be a novel organ donor intervention to prevent primary graft dysfunction.

Combination therapies for traumatic brain injury: prospective considerations

Traumatic brain injury (TBI) initiates a cascade of numerous pathophysiological events that evolve over time.Despite the complexity of TBI, research aimed at therapy development has almost exclusively focused on single therapies, all of which have failed in multicenter clinical trials. Therefore, in February 2008 the National Institute of Neurological Disorders and Stroke, with support from the National Institute of Child Health and Development, the National Heart, Lung, and Blood Institute, and the Department of Veterans Affairs, convened a workshop to discuss the opportunities and challenges of testing combination therapies for TBI. Workshop participants included clinicians and scientists from a variety of disciplines, institutions, and agencies. The objectives of the workshop were to: (1) identify the most promising combinations of therapies for TBI; (2) identify challenges of testing combination therapies in clinical and pre-clinical studies; and (3) propose research methodologies and study designs to overcome these challenges. Several promising combination therapies were discussed, but no one combination was identified as being the most promising. Rather, the general recommendation was to combine agents with complementary targets and effects (e.g., mechanisms and time-points), rather than focusing on a single target with multiple agents. In addition, it was recommended that clinical management guidelines be carefully considered when designing pre-clinical studies for therapeutic development.To overcome the challenges of testing combination therapies it was recommended that statisticians and the U.S. Food and Drug Administration be included in early discussions of experimental design. Furthermore, it was agreed that an efficient and validated screening platform for candidate therapeutics, sensitive and clinically relevant biomarkers and outcome measures, and standardization and data sharing across centers would greatly facilitate the development of successful combination therapies for TBI. Overall there was great enthusiasm for working collaboratively to act on these recommendations.

Review article: hypertonic saline use in the emergency department

Hypertonic saline (HS) is being increasingly used for the management of a variety of conditions, most notably raised intracranial pressure. This article reviews the available evidence on HS solutions as they relate to emergency medicine, and develops a set of recommendations for its use. To conclude, HS is recommended as an alternative to mannitol for treating raised intracranial pressure in traumatic brain injury. HS is also recommended for treating severe and symptomatic hyponatremia, and is worth considering for both recalcitrant tricyclic antidepressant toxicity and for cerebral oedema complicating paediatric diabetic ketoacidosis. HS is not recommended for hypovolaemic resuscitation.

Effect of hypertonic saline concentration on cerebral and visceral organ water in an uninjured rodent model

OBJECTIVE

Hypertonic saline has been shown to be an effective osmotic agent to reduce brain water and hence brain volume and intracranial pressure. A direct correlation between dose and effect has been demonstrated, but no studies have compared the effects of different concentrations of the same osmotic load of hypertonic saline over time. We compared the effects of different tonicity of infused hypertonic saline on cerebral, lung, and small bowel water extraction over time under controlled conditions.

DESIGN

Laboratory study.

SETTING

Medical school.

SUBJECTS

Male Wistar rats (280-450 g).

INTERVENTIONS

Anesthetized rats were randomized to a 15-min intravenous bolus infusion of 0.9% NaCl or five equisodium but different concentrations of hypertonic saline: 4.2%, 7.5%, 10%, 23.4%, and 30%. Following infusion, animals remained anesthetized for 60, 180, or 300 mins without additional fluids given (n > or = 6 per group). Blood was sampled, total urine output was measured, and the animal was then killed under deep anesthesia. Cerebral, lung, and small bowel water contents were derived by wet/dry weight measures.

MEASUREMENTS AND MAIN RESULTS

After 60 mins, hypertonic saline administered at 50 mosm/kg resulted in an increase in serum osmolarity in all hypertonic saline groups (p < .05 vs. normal saline), with a significantly greater increase measured using 23.4% or 30% hypertonic saline (23.4%, 365.0 +/- 8.8 mosm/L, p < .05 vs. other lesser hypertonic saline doses). The durable effect was present throughout the 300-min period by all but the lowest hypertonic saline (4.2% NaCl). Lung but not small bowel organ water was diminished by hypertonic saline. Brain water content (79.1 +/- 0.2% in normal saline controls) was, however, significantly reduced.

CONCLUSIONS

Hypertonic saline is effective in reducing organ water content in a setting of preserved blood-brain barrier but is not as effective in visceral organs. At equiosmotic doses of hypertonic saline, concentration plays no substantial role in altering serum osmolarity but appears to benefit duration of action. At very high concentrations, such as 23.4% NaCl, additional water extraction is also manifested. At such high concentration of NaCl, tonicity, indeed, matters, especially in water shifts across the blood-brain barrier.