Small-volume resuscitation: from experimental evidence to clinical routine. Advantages and disadvantages of hypertonic solutions

Hypertonic treatment of acute respiratory distress syndrome

Many viral infections, including the COVID-19 infection, are associated with the hindrance of blood oxygenation due to the accumulation of fluid, inflammatory cells, and cell debris in the lung alveoli. This condition is similar to Acute Respiratory Distress Syndrome (ARDS). Mechanical positive-pressure ventilation is often used to treat this condition, even though it might collapse pulmonary capillaries, trapping red blood cells and lowering the lung's functional capillary density. We posit that the hyperosmotic-hyperoncotic infusion should be explored as a supportive treatment for ARDS. As a first step in verifying the feasibility of this ARDS treatment, we model the dynamics of alveolar fluid extraction by osmotic effects. These are induced by increasing blood plasma osmotic pressure in response to the increase of blood NaCl concentration. Our analysis of fluid drainage from a plasma-filled pulmonary alveolus, in response to the intravenous infusion of 100 ml of 1.28 molar NaCl solution, shows that alveoli empty of fluid in approximately 15 min. These modeling results are in accordance with available experimental and clinical data; no new data were collected. They are used to calculate the temporal change of blood oxygenation, as oxygen diffusion hindrance decreases upon absorption of the alveolar fluid into the pulmonary circulation. Our study suggests the extraordinary speed with which beneficial effects of the proposed ARDS treatment are obtained and highlight its practicality, cost-efficiency, and avoidance of side effects of mechanical origin.

Nonthyroidal illness syndrome (NTIS) in severe COVID-19 patients: role of T3 on the Na/K pump gene expression and on hydroelectrolytic equilibrium

Background

Nonthyroidal Illness Syndrome (NTIS) can be detected in many critical illnesses. Recently, we demonstrated that this condition is frequently observed in COVID-19 patients too and it is correlated with the severity the disease. However, the exact mechanism through which thyroid hormones influence the course of COVID-19, as well as that of many other critical illnesses, is not clear yet and treatment with T4, T3 or a combination of both is still controversial. Aim of this study was to analyze body composition in COVID-19 patients in search of possible correlation with the thyroid function.

Methods and findings

We report here our experience performed in 74 critically ill COVID-19 patients hospitalized in the intensive care unit (ICU) of our University Hospital in Rome. In these patients, we evaluated the thyroid hormone function and body composition by Bioelectrical Impedance Analysis (BIA) during the acute phase of the disease at admission in the ICU. To examine the effects of thyroid function on BIA parameters we analyzed also 96 outpatients, affected by thyroid diseases in different functional conditions. We demonstrated that COVID-19 patients with low FT3 serum values exhibited increased values of the Total Body Water/Free Fat Mass (TBW/FFM) ratio. Patients with the lowest FT3 serum values had also the highest level of TBW/FFM ratio. This ratio is an indicator of the fraction of FFM as water and represents one of the best-known body-composition constants in mammals. We found an inverse correlation between FT3 serum values and this constant. Reduced FT3 serum values in COVID-19 patients were correlated with the increase in the total body water (TBW), the extracellular water (ECW) and the sodium/potassium exchangeable ratio (Na_e:K_e), and with the reduction of the intracellular water (ICW). No specific correlation was observed in thyroid patients at different functional conditions between any BIA parameters and FT3 serum values, except for the patient with myxedema, that showed a picture similar to that seen in COVID-19 patients with NTIS. Since the Na⁺/K⁺ pump is a well-known T3 target, we measured the mRNA expression levels of the two genes coding for the two major isoforms of this pump. We demonstrated that COVID-19 patients with NTIS had lower levels of mRNA of both genes in the peripheral blood mononuclear cells (PBMC)s obtained from our patients during the acute phase of the disease. In addition, we retrieved data from transcriptome analysis, performed on human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM)s treated with T3 and we demonstrated that in these cells T3 is able to stimulate the expression of these two genes in a dose-dependent manner.

Conclusions

In conclusion, we demonstrated that measurement of BIA parameters is a useful method to analyze water and salt retention in COVID-19 patients hospitalized in ICU and, in particular, in those that develop NTIS. Our results indicate that NTIS has peculiar similarities with myxedema seen in severe hypothyroid patients, albeit it occurs more rapidly. The Na⁺/K⁺ pump is a possible target of T3 action, involved in the pathogenesis of the anasarcatic condition observed in our COVID-19 patients with NTIS. Finally, measurement of BIA parameters may represent good endpoints to evaluate the benefit of future clinical interventional trials, based on the administration of T3 in patients with NTIS.

Hypotheses about sub-optimal hydration in the weeks before coronavirus disease (COVID-19) as a risk factor for dying from COVID-19

To address urgent need for strategies to limit mortality from coronavirus disease 2019 (COVID-19), this review describes experimental, clinical and epidemiological evidence that suggests that chronic sub-optimal hydration in the weeks before infection might increase risk of COVID-19 mortality in multiple ways. Sub-optimal hydration is associated with key risk factors for COVID-19 mortality, including older age, male sex, race-ethnicity and chronic disease. Chronic hypertonicity, total body water deficit and/or hypovolemia cause multiple intracellular and/or physiologic adaptations that preferentially retain body water and favor positive total body water balance when challenged by infection. Via effects on serum/glucocorticoid-regulated kinase 1 (SGK1) signaling, aldosterone, tumor necrosis factor-alpha (TNF-alpha), vascular endothelial growth factor (VEGF), aquaporin 5 (AQP5) and/or Na⁺/K⁺-ATPase, chronic sub-optimal hydration in the weeks before exposure to COVID-19 may conceivably result in: greater abundance of angiotensin converting enzyme 2 (ACE2) receptors in the lung, which increases likelihood of COVID-19 infection, lung epithelial cells which are pre-set for exaggerated immune response, increased capacity for capillary leakage of fluid into the airway space, and/or reduced capacity for both passive and active transport of fluid out of the airways. The hypothesized hydration effects suggest hypotheses regarding strategies for COVID-19 risk reduction, such as public health recommendations to increase intake of drinking water, hydration screening alongside COVID-19 testing, and treatment tailored to the pre-infection hydration condition. Hydration may link risk factors and pathways in a unified mechanism for COVID-19 mortality. Attention to hydration holds potential to reduce COVID-19 mortality and disparities via at least 5 pathways simultaneously.

Effect of 7.5% hypertonic saline solution on whole blood coagulation in healthy dogs using thromboelastography

Objective

To evaluate the effects of 7.5% hypertonic saline solution (HSS) on whole blood coagulation in healthy dogs and to compare electrolyte and osmolality measurements between in vivo and in vitro dilution with HSS.

Design

Experimental study.

Setting

University teaching hospital.

Animals

Twelve adult purpose‐bred Beagles.

Interventions

All 12 dogs received 5 mL/kg 7.5% HSS at 1 mL/kg/min. After a 14‐day washout period, 5 of these dogs were randomly selected and received the same volume of 0.9% NaCl. Blood samples were collected before infusion, immediately after infusion, and at 30, 60, and 90 minutes after infusion for the measurement of coagulation using thromboelastography. For comparison of electrolyte concentrations and osmolality between in vitro dilution and in vivo dilution of HSS, 6‐mL blood samples were diluted with 7.5% HSS (1:18 ratio) at baseline.

Measurements and Main Results

None of the thromboelastography variables differed significantly between the 7.5% HSS group and the 0.9% NaCl group. The sodium and chloride levels, and the osmolality, were significantly increased at all postinfusion time points compared to baseline, while those levels were significantly higher with in vitro dilution than all postinfusion time points. However, almost all the values gradually decreased and became similar to baseline values in case of in vivo dilution.

Conclusions

The clinically relevant dose of 7.5% HSS (5 mL/kg) did not affect whole blood coagulation significantly in healthy Beagles. Further studies are necessary to assess the effect of HSS on blood coagulation in canine patients with shock.

Hypertonic saline attenuates the cytokine-induced pro-inflammatory signature in primary human lung epithelia

Trauma/hemorrhagic shock is a complex physiological phenomenon that leads to dysregulation of many molecular pathways. For over a decade, hypertonic saline (HTS) has been used as an alternative resuscitation fluid in the setting of trauma/hemorrhagic shock. In addition to restoring circulating volume within the vascular space, studies have shown a positive immunomodulatory effect of HTS. Targeted studies have shown that HTS affects the transcription of several pro-inflammatory cytokines by inhibiting the NF-κB-IκB pathway in model cell lines and rats. However, few studies have been undertaken to assess the unbiased effects of HTS on the whole transcriptome. This study was designed to interrogate the global transcriptional responses induced by HTS and provides insight into the underlying molecular mechanisms and pathways affected by HTS. In this study, RNA sequencing was employed to explore early changes in transcriptional response, identify key mediators, signaling pathways, and transcriptional modules that are affected by HTS in the presence of a strong inflammatory stimulus. Our results suggest that primary human small airway lung epithelial cells (SAECS) exposed to HTS in the presence and absence of a strong pro-inflammatory stimulus exhibit very distinct effects on cellular response, where HTS is highly effective in attenuating cytokine-induced pro-inflammatory responses via mechanisms that involve transcriptional regulation of inflammation which is cell type and stimulus specific. HTS is a highly effective anti-inflammatory agent that inhibits the chemotaxis of leucocytes towards a pro-inflammatory gradient and may attenuate the progression of both the innate and adaptive immune response.

Combinatorial therapy with two pro-coagulants and one osmotic agent reduces the extent of the lesion in the acute phase of spinal cord injury in the rat

Background

Spinal cord injury (SCI) is a complex disease that leads to a motor, sensitive, and vegetative impairment. So far, single therapies are ineffective for treating SCI in humans and a multifactorial therapeutic approach may be required. The aim of this work was to assess the effect of a triple therapy (TT) associating two pro-coagulant therapies (tranexamic acid and fibrinogen) with an anti-edema therapy (hypertonic saline solution), on the extent of the lesion 24 h post-injury.

Methods

The design of this study is a randomized controlled study. The setting of this study is an experimental study.

Male Wistar rats were assigned to receive saline solution for the control group or one of the treatment, or a combination of two treatments or the three treatments (triple therapy group (TT)). Animals were anesthetized and received a weight-drop SCI induced at the level of the 12th thoracic vertebra (Th12). They were treated by single therapies, double therapies, or TT started 5 min after the SCI.

Results

The extent of the lesion was assessed 24 h after injury by spectrophotometry (quantification of parenchymal hemorrhage and blood-spinal cord barrier disruption) and by histology (quantification of spared neuronal tissue).

As compared with the control group, the TT significantly reduced parenchymal hemorrhage (p < 0.05) and improved the total amount of intact neural tissue, measured 24 h later (p = 0.003).

Conclusions

Combinatorial therapy associating two pro-coagulants (tranexamic acid and fibrinogen) with an anti-edema therapy (hypertonic saline solution) reduces the extent of the lesion in the acute phase of spinal cord injury in the rat.

Evaluation of the clinical effect of small-volume resuscitation on uncontrolled hemorrhagic shock in emergency

OBJECTIVE

The objective of the present study was to explore the resuscitative effect of small-volume resuscitation on uncontrolled hemorrhagic shock in emergency.

METHODS

In this study, the resuscitative effects in 200 trauma patients with uncontrolled hemorrhagic shock in emergency were studied. Half of these patients were infused with hypertonic/hyperoncotic fluid (small-volume resuscitation group, n=100), whereas the rest were infused with Hespan and lactated Ringer's solution (conventional fluid resuscitation group, n=100). The changes in hemodynamics, coagulation function, blood biochemistry, blood hematology, and the average infusion volume in both the groups were comparatively studied.

RESULTS

It was found that the hemodynamics were improved in both the groups after resuscitation. Interestingly, compared with trauma patients infused with Hespan and lactated Ringer's solution, the growth rate, range, and time duration of the mean arterial pressure of the patients in small-volume resuscitation group increased significantly, and the shock index decreased progressively; in the 60th min after the resuscitation, blood index including hemoglobin, hematocrit, red blood cells, white blood cells, and platelet declined, whereas prothrombin time and activated partial thromboplastin time were prolonged in both the groups, but these changes were less obvious in the small-volume group. In addition, the average infusion volume of patients in the small-volume group was less than that of patients in conventional fluid resuscitation group.

CONCLUSION

Featured with small infusion volume and less influence to coagulation function and homeostasis of human body, small-volume resuscitation possesses a significantly higher resuscitative effect. Therefore, trauma patients may have a better chance to maintain the hemodynamic stability and the survival rate, or recovery speed will be increased when traditional aggressive fluid resuscitation is replaced by small-volume resuscitation.

Hibernation-based blood loss therapy increases survivability of lethal hemorrhagic shock in rats

A small-volume (1 ml/kg) resuscitation fluid based on metabolic adaptations in hibernating mammals was optimized using a rat model of hemorrhagic shock. A previous study of this therapy tested only one concentration of three specific components: 4 M D-stereoisomer of beta-hydroxybutyrate (BHB), 43 mM melatonin, and 20% DMSO. In this study, we considered the range of concentrations of BHB and melatonin seen during the physiological extremes of rapid arousal from hypothermic torpor in natural hibernators and applied these to the non-hibernating Sprague-Dawley rat model. These extremes normally result in ischemia and reperfusion injury in non-hibernating mammals. Dose-ranging studies were conducted for BHB and melatonin in rats with 60% blood loss. BHB was administered at either 4, 2, or 0.4 M concentration in conjunction with 4.3 mM melatonin and 10% DMSO. Subsequently, melatonin was administered at either 4.3, 0.43, 0.0043, 0.000043, or 0 mM in conjunction with 4 M BHB and 2% DMSO. 10-day mean survival showed a dose-dependent trend: rats survived longer with higher concentration of infused BHB (4 M BHB, 7.38 ± 1.75 days; 2 M BHB, 5.25 ± 2.22 days; 0.4 M BHB, 2.07 ± 2.05 days). Administering 4 M BHB without melatonin resulted in low mean survival times (4.38 ± 1.42 days). All treatments containing both 4 M BHB and melatonin, regardless of melatonin concentration, resulted in mean survival times of ~7.5 days. We conclude there is a dose-dependent trend in which higher BHB concentration resulted in improved survival over 10 days.

Plasma hyperosmolality improves tolerance to combined heat stress and central hypovolemia in humans

Heat stress profoundly impairs tolerance to central hypovolemia in humans via a number of mechanisms including heat-induced hypovolemia. However, heat stress also elevates plasma osmolality; the effects of which on tolerance to central hypovolemia remain unknown. This study examined the effect of plasma hyperosmolality on tolerance to central hypovolemia in heat-stressed humans. With the use of a counterbalanced and crossover design, 12 subjects (1 female) received intravenous infusion of either 0.9% iso-osmotic (ISO) or 3.0% hyperosmotic (HYPER) saline. Subjects were subsequently heated until core temperature increased ~1.4°C, after which all subjects underwent progressive lower-body negative pressure (LBNP) to presyncope. Plasma hyperosmolality improved LBNP tolerance (ISO: 288 ± 193 vs.

HYPER

382 ± 145 mmHg × min, P = 0.04). However, no differences in mean arterial pressure (P = 0.10), heart rate (P = 0.09), or muscle sympathetic nerve activity (P = 0.60, n = 6) were observed between conditions. When individual data were assessed, LBNP tolerance improved ≥25% in eight subjects but remained unchanged in the remaining four subjects. In subjects who exhibited improved LBNP tolerance, plasma hyperosmolality resulted in elevated mean arterial pressure (ISO: 62 ± 10 vs.

HYPER

72 ± 9 mmHg, P < 0.01) and a greater increase in heart rate (ISO: +12 ± 24 vs. HYPER: +23 ± 17 beats/min, P = 0.05) before presyncope. No differences in these variables were observed between conditions in subjects that did not improve LBNP tolerance (all P ≥ 0.55). These results suggest that plasma hyperosmolality improves tolerance to central hypovolemia during heat stress in most, but not all, individuals.

Comparison of the in vitro effects of saline, hypertonic hydroxyethyl starch, hypertonic saline, and two forms of hydroxyethyl starch on whole blood coagulation and platelet function in dogs

OBJECTIVE

To compare the in vitro effects of hypertonic solutions and colloids to saline on coagulation in dogs.

DESIGN

In vitro experimental study.

SETTING

Veterinary teaching hospital.

ANIMALS

Twenty-one adult dogs.

INTERVENTIONS

Blood samples were diluted with saline, 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH), 7.2% hypertonic saline (HTS), hydroxyethyl starch (HES) 130/0.4 or hydroxyethyl starch 600/0.75 at ratios of 1:22 and 1:9, and with saline and HES at a ratio of 1:3.

MEASUREMENTS AND MAIN RESULTS

Whole blood coagulation was analyzed using rotational thromboelastometry (extrinsic thromboelastometry-cloting time (ExTEM-CT), maximal clot firmness (MCF) and clot formation time (CFT) and fibrinogen function TEM-CT (FibTEM-CT) and MCF) and platelet function was analyzed using a platelet function analyzer (closure time, CTPFA ). All parameters measured were impaired by saline dilution. The CTPFA was prolonged by 7.2% hypertonic saline solution with 6% hydroxyethylstarch with an average molecular weight of 200 kDa and a molar substitution of 0.4 (HH) and HTS but not by HES solutions. At clinical dilutions equivalent to those generally administered for shock (saline 1:3, HES 1:9, and hypertonic solutions 1:22), CTPFA was more prolonged by HH and HTS than other solutions but more by saline than HES. No difference was found between the HES solutions or the hypertonic solutions. ExTEM-CFT and MCF were impaired by HH and HTS but only mildly by HES solutions. At clinically relevant dilutions, no difference was found in ExTEM-CFT between HTS and saline or in ExTEM-MCF between HH and saline. No consistent difference was found between the 2 HES solutions but HH impaired ExTEM-CFT and MCF more than HTS. At high dilutions, FibTEM-CT and -MCF and ExTEM-CT were impaired by HES.

CONCLUSIONS

Hypertonic solutions affect platelet function and whole blood coagulation to a greater extent than saline and HES. At clinically relevant dilutions, only CTPFA was markedly more affected by hypertonic solutions than by saline. At high dilutions, HES significantly affects coagulation but to no greater extent than saline at clinically relevant dilutions.

Prehospital fluid management of abdominal organ trauma patients--a matched pair analysis

PURPOSE

Severe bleeding after trauma frequently leads to a poor outcome. Prehospital fluid replacement therapy is considered an important primary treatment option. We conducted a retrospective matched pair analysis to assess the influence of prehospital fluid replacement volume on the clinical course of patients with solid abdominal organ trauma.

METHODS

Data were analyzed from 51,425 patients in TraumaRegister DGU® of the German Trauma Society. Inclusion criteria were as follows: injury severity score ≥ 16 points, primary admission, age ≥ 16 years, no isolated brain injury, transfusion of at least one unit of packed red blood cells (pRBCs), and systolic blood pressure ≥ 20 mmHg at the accident site. The patients were divided into "low-volume" (0-1000 ml) and "high-volume" (≥ 1,500 ml) groups according to the matched pair criteria. In each group, 68 patients met the inclusion criteria.

RESULTS

Higher volume in fluid replacement was associated with increased need for transfusion (pRBCs: low-volume: 7.71 units, high-volume: 9.16 units; p = 0.074) and with by trend reduced clotting ability (prothrombin time: low-volume: 71.47 %, high-volume: 66.47 %; p = 0.27). The percentage of patients in shock (systolic blood pressure <90 mmHg) upon admission was equal in the two groups (25.0 %; p = 1). The mortality rate was discretely higher in the high-volume group (low-volume: 11.8 %, high-volume: 19.1 %; p = 0.089).

CONCLUSIONS

Excessive prehospital fluid replacement is able to lead in an increased mortality rate in patients with solid abdominal organ injury. Our results support the concept of restrained fluid replacement in the preclinical treatment of severe trauma patients.

Effect of hypertonic saline on hypotension following induction of general anesthesia: A randomized controlled trial

Background:

The aim of this study was to examine the effects of preoperatively administered i.v. hypertonic saline on hypotension following induction of general anesthesia.

Materials and Methods:

Fifty-four patients who scheduled for elective surgery were randomly allocated to two groups of 27 patients who received hypertonic saline 5% (2.3 ml/kg) or received normal saline (13 ml/kg). Infusion of hypertonic saline was done half an hour before induction of anesthesia during 30 minutes. Anesthesia was conducted in a standard protocol for all patients. Age, sex, body mass index (BMI), systolic and diastolic blood pressure (SBP, DBP), heart rate (HR) and mean arterial pressure (MAP) were assessed in all patients.

Results:

The mean age of patients was 36.68 ± 10.8 years. Forty percent of patients were male. The mean SBP at min 2 and min 5, mean of DBP at min 2, 5, and 15, mean of HR at all time points and mean of MAP at min 2 and 15 between groups were no significantly different (P > 0.05), but mean of SBP at min 10 and 15, mean of DBP at min 10, and mean of MAP at min 5 and 10 in hypertonic saline group was significantly more than the normal group (P < 0.05). Trend of SBP, DBP, HR and MAP between groups were not significantly different (P > 0.05).

Conclusions:

Infusion of hypertonic saline 5% (2.3 mg/kg) before the general anesthesia led to a useful reduction in MAP and reduced heart rate, with no episodes of severe hypotension.

Small volume resuscitation with hypertonic sodium chloride solution in cattle undergoing surgical correction of abomasal volvulus

A randomized clinical trial was conducted to compare the efficacy of rapid intravenous (IV) infusion of a 7.2% hypertonic saline solution with that of continuous application of an isotonic solution in stabilizing the circulation of cows with abomasal volvulus. Cattle treated with hypertonic saline had a significantly greater reduction in volume deficit within the first 10 min of therapy than cows treated with isotonic saline (from 5.9 ± 4.8 to 2.1 ± 4.4 L/100 kg vs. 7.0 ± 4.5 to 4.9 ± 3.8 L/100 kg, respectively). The central venous pressure (CVP) of the cows given the hypertonic saline rose within the first 10 min of therapy from 7.3 ± 3.5 to 10.8 ± 3.4 cm H2O, while the CVP of the cattle treated with isotonic saline did not increase significantly during this time. Sixty minutes after the start of the infusion, the CVP of the isotonic group was still significantly lower than that of the hypertonic group (9.5 ± 2.1 vs. 10.3 ± 3.3 cm H2O, respectively). Within the first 60 min, the base excess decreased from 5.5 ± 6.9 to 4.7 ± 6.2 mmol/L in the hypertonic group whereas it increased from 5.6 ± 5.7 to 6.8 ± 5.4 mmol/L in the isotonic group. These results suggest that for cows with abomasal volvulus, IV therapy with hypertonic saline may improve the haemodynamic and circulatory situation considerably faster and more effectively than continuous infusion with isotonic saline.

Does increased prehospital replacement volume lead to a poor clinical course and an increased mortality? A matched-pair analysis of 1896 patients of the Trauma Registry of the German Society for Trauma Surgery who were managed by an emergency doctor at the accident site

INTRODUCTION

Severe bleeding after trauma frequently leads to a poor outcome. Prehospital fluid replacement therapy is regarded as an important primary treatment option. Our study aimed to assess the influence of prehospital fluid replacement therapy on the post-traumatic course of severely injured patients in a retrospective analysis of matched pairs.

PATIENTS AND METHODS

The data of 51,425 patients of the Trauma Registry of the German Society for Trauma Surgery were analysed. The following patients were included: Injury Severity Score ≥ 16 points, primary admission, age ≥ 16 years, no isolated brain injury, transfusion of at least one unit of packed red blood cells (pRBC), systolic blood pressure ≥ 60 mmHg at the accident site. The patients were divided into two groups according to the following matched-pair criteria (low-volume: 0-1500 ml prehospital volume replaced; high-volume: ≥ 1501 ml prehospital volume): intubation at the accident site (yes/no), time from injury to hospital ± 10 min., means of rescue (emergency helicopter, MICU), Abbreviated Injury Scale (body regions), injury year, systolic blood pressure and age (years). All patients were managed by an emergency doctor at the accident site.

RESULTS

A total of 948 patients in each group met the inclusion criteria. Increasing replacement volume was associated with an increased need for transfusion (pRBCs: low-volume: 7 units, high-volume: 8.3 units; p<0.001) and a reduced ability to coagulate (prothrombin ratio (PR): low-volume: 68%, high-volume: 61.5%; p<0.001). Patients in shock (systolic BP<90 mmHg) upon admission to the hospital were equally in both groups (25.6%; p=0.98). Significantly higher lethality was observed in cases of increasing volume (low-volume: 22.7%, high-volume: 27.6%; p<0.01).

CONCLUSIONS

Excessive prehospital fluid replacement leads to an increased mortality rate. The results of this study support the concept of restrained volume replacement in the prehospital treatment of patients with severe trauma.

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.

Anesthesia for the horse with colic

This article discusses anesthesia for horses with colic from acute gastrointestinal disease. Emphasis is placed on new developments in pre-, intra-, and immediate postoperative management over the last decade, including early goal-directed therapy (EGDT) in the resuscitation of septic patients, the controversy over the optimal fluid type to administer, and the management of complications, such as cardiovascular depression, hypoventilation and hypoxemia, and decreased colloid oncotic pressure (COP). An update on analgesia is also provided; older drugs such as ketamine and lidocaine are increasingly being recognized both for their analgesic properties and other potentially beneficial effects in endotoxemic horses.

Intravenous infusion of hyperosmotic NaCl solution induces acute cor pulmonale in anesthetized rats

Intravenous hyperosmotic NaCl infusion is an effective treatment for circulatory shock. However, a fast infusion rate (2 mL/kg at the rate of 1 mL/s) induces transient hypotension. This response has been reported to be due to decreased total peripheral resistance and/or decreased cardiac performance. Although the hypotension is transient and recovers within 2 min without detrimental consequences, it is important to understand the associated hemodynamics and mechanisms. We found that the hypotensive effect was larger with intravenous NaCl infusion than with intra-aortic infusion, indicating that change in cardiac performance played a more significant role than change in peripheral resistance. NaCl infusion induced an increase in pulmonary vascular resistance and central venous pressure and a decrease in right ventricular dP/dt max, suggesting acute cor pulmonale. Diastolic ventricular crosstalk-induced left ventricular failure was also observed. Hyperosmotic NaCl-induced hypotension was therefore mainly due to a combination of acute cor pulmonale and left ventricular failure.

Influence of prehospital fluid resuscitation on patients with multiple injuries in hemorrhagic shock in patients from the DGU trauma registry

Background:

Severe bleeding as a result of trauma frequently leads to poor outcome by means of direct or delayed mechanisms. Prehospital fluid therapy is still regarded as the main option of primary treatment in many rescue situations. Our study aimed to assess the influence of prehospital fluid replacement on the posttraumatic course of severely injured patients in a retrospective analysis of matched pairs.

Materials and Methods:

We reviewed data from 35,664 patients recorded in the Trauma Registry of the German Society for Trauma Surgery (DGU). The following patients were selected: patients having an Injury Severity Score >16 points, who were ≥16 years of age, with trauma, excluding those with craniocerebral injuries, who were admitted directly to the participating hospitals from the accident site. All patients had recorded values for replaced volume and blood pressure, hemoglobin concentration, and units of packed red blood cells given. The patients were matched based on similar blood pressure characteristics, age groups, and type of accident to create pairs. Pairs were subdivided into two groups based on the volumes infused prior to hospitalization: group 1: 0-1500 (low), group 2: ≥2000 mL (high) volume.

Results:

We identified 1351 pairs consistent with the inclusion criteria. Patients in group 2 received significantly more packed red blood cells (group 1: 6.9 units, group 2: 9.2 units; P=0.001), they had a significantly reduced capacity of blood coagulation (prothrombin ratio: group 1: 72%, group 2: 61.4%; P≤0.001), and a lower hemoglobin value on arrival at hospital (group 1: 10.6 mg/dL, group 2: 9.1 mg/dL; P≤0.001). The number of ICU-free days concerning the first 30 days after trauma was significantly higher in group 1 (group 1: 11.5 d, group 2: 10.1 d; P≤0.001). By comparison, the rate of sepsis was significantly lower in the first group (group 1: 13.8%, group 2: 18.6%; P=0.002); the same applies to organ failure (group 1: 36.0%, group 2: 39.2%; P≤0.001).

Conclusion:

The high amounts of intravenous fluid replacement was related to early traumatic coagulopathy, organ failure, and sepsis rate.

[Septic shock. Update of treatment using hypertonic saline and antidiuretic hormone-vasopressin]

Safety in the use of small volumes of hypertonic saline solution for hypovolaemic shock and in the treatment of intracranial hypertension has been demonstrated in studies in the field of resuscitation. There is little experience of this for septic shock in humans. Beneficial immunomodulatory effects have been detected in pre-clinical studies. Interactions with the pituitary-adrenal axis and with the secretion of anti-diuretic hormone are varied and suggestive, but are not sufficiently understood. On the other hand, vasopressin has cardiovascular, osmoregulatory, and coagulation effects, and also acts on the hypothalamic-pituitary-adrenal axis. There is a relative deficit of vasopressin in septic shock. Its use in these patients does not seem to have any advantages as regards mortality, but may be beneficial in patients at risk from acute renal failure, or those who receive corticosteroids. Terlipressin is a vasopressin analogue that has also been studied. The synergy between vasopressin and hypertonic saline is a hypothesis that is mainly supported in pre-clinical studies. The use of hypertonic saline solution in septic shock, although promising, is still experimental, and must be restricted to the field of controlled clinical trials.

Unexpected 100% survival following 60% blood loss using small-volume 7.5% NaCl with adenocaine and Mg(2+) in the rat model of extreme hemorrhagic shock

Hemorrhage is responsible for up to 40% of trauma mortality, and of these deaths, 33% to 56% occur during the prehospital period. In an effort to translate the cardioprotective effects of Adenocaine (adenosine, lidocaine) and Mg (ALM) from cardiac surgery to resuscitation science, we examined the early resuscitative effects of 7.5% NaCl with ALM in the rat model of 60% blood loss. Male Sprague-Dawley rats (250-350 g, n = 40) were anesthetized and randomly assigned to one of five groups: (a) untreated, (b) 7.5% NaCl, (c) 7.5% NaCl/6% dextran 70, (d) 7.5% NaCl/Mg, and (e) 7.5% NaCl/ALM. Blood withdrawal occurred over ∼50 min (MAP 30-35 mmHg), and rats were left in shock for 30 min. Total shock time was ∼80 min; 0.3-mL bolus was injected intravenously over 10 s, and hemodynamics monitored for 60 min (phase 1). Shed blood was reinfused and function monitored for a further 60 min (phase 2). Lead II electrocardiogram, arterial pressures, mean arterial pressure (MAP), pulse pressure (PP), heart rate (HR), and rate-pressure product were monitored. Mortality was as follows: untreated (100%), 7.5% NaCl (75%), 7.5% NaCl/6% dextran 70 (87.5%), 7.5% NaCl/Mg (62.5%), and 7.5% NaCl/ALM (0%). Deaths occurred at different times depending on treatment group and paralleled differences in the total number of ventricular arrhythmias with the highest number in untreated animals (49 ± 17) and lowest in 7.5% NaCl/ALM rats (2 ± 1.8) (P < 0.05). At the end of phase 1, MAP of 7.5% NaCl/ALM-treated animals increased from 29 to 40 mmHg (P < 0.05). At the end of phase 2, MAP, PP, HR, and rate-pressure product in the ALM group were 75%, 193%, 96%, and 83% of their preshock values. Small-volume (∼1 mL/kg) i.v. bolus of 7.5% NaCl/ALM led to 100% survival following 60% blood loss with higher MAP than any group, an 89% to 96% reduction in the total number of arrhythmias, and a stable HR.

[Lethality and outcome in multiple injured patients after severe abdominal and pelvic trauma. Influence of preclinical volume replacement - an analysis of 604 patients from the trauma registry of the DGU]

BACKGROUND

Uncontrollable hemorrhaging after blunt trauma and the resulting hemorrhagic shock is still one of the main causes of death in trauma patients. Starting volume replacement before admission to hospital is one of the main pillars of immediate treatment. The statements concerning the quantity of the preclinically administered fluid are still controversial and have a low level of evidence in the literature. Massive abdominal trauma and unstable pelvic fractures belong to the most relevant causes of hemorrhagic shock. The aim of this study was to analyze the influence of the quantity of the preclinically administered fluid on the posttraumatic course of patients with massive abdominal and pelvic injuries.

PATIENTS AND METHODS

All patients of the trauma registry of the DGU (German Society for Trauma Surgery) who met the following criteria were included: injury severity score ≥16 points, primary admission to hospital, age ≥16 years, initial blood pressure <100 mmHg and transfusion of erythrocyte concentrate (EC). Out of this collective patients with an AIS abdomen ≥4 or an AIS pelvis ≥4 were analyzed. Both groups were divided into 4 subgroups subject to the preclinically infused volume (<1000 ml, 1000-2000 ml, 2001-3000 ml and >3000 ml).

RESULTS

Of the 375 patients with abdominal trauma and 229 patients with pelvic trauma were consistent with the inclusion criteria. In both groups an increasing volume replacement was associated with an increased need for transfusion and a reduction of the coagulation ability (Quick 61% in the case of <1000 ml versus 49.1% in the case of >3000 ml). The rescue time had a relevant influence on the quantity of preclinically infused volume (62 min for <1000 ml versus 88 min for >3000 ml). On admission to hospital the blood pressure values were on average the same in all patients (~ 95 mmHg). With an increasing volume a slight elevation of lethality was found as well as a significant increase of the transfused erythrocyte concentrates, a significant deterioration of coagulation and an increase of patients with mass transfusions.

CONCLUSION

In the case of a preclinical relevant bleeding after blunt pelvic or abdominal trauma moderate volume replacement (<1000 ml) results in an enhancement of the initial coagulation situation and in a reduction in the need for transfusion. The results of this study support the concept of a restrained volume therapy after massive trauma with and bleeding requiring transfusion.

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.

In vitro impairment of whole blood coagulation and platelet function by hypertonic saline hydroxyethyl starch

Background

Hypertonic saline hydroxyethyl starch (HH) has been recommended for first line treatment of hemorrhagic shock. Its effects on coagulation are unclear. We studied in vitro effects of HH dilution on whole blood coagulation and platelet function. Furthermore 7.2% hypertonic saline, 6% hydroxyethylstarch (as ingredients of HH), and 0.9% saline solution (as control) were tested in comparable dilutions to estimate specific component effects of HH on coagulation.

Methods

The study was designed as experimental non-randomized comparative in vitro study. Following institutional review board approval and informed consent blood samples were taken from 10 healthy volunteers and diluted in vitro with either HH (HyperHaes^®, Fresenius Kabi, Germany), hypertonic saline (HT, 7.2% NaCl), hydroxyethylstarch (HS, HAES6%, Fresenius Kabi, Germany) or NaCl 0.9% (ISO) in a proportion of 5%, 10%, 20% and 40%. Coagulation was studied in whole blood by rotation thrombelastometry (ROTEM) after thromboplastin activation without (ExTEM) and with inhibition of thrombocyte function by cytochalasin D (FibTEM), the latter was performed to determine fibrin polymerisation alone. Values are expressed as maximal clot firmness (MCF, [mm]) and clotting time (CT, [s]). Platelet aggregation was determined by impedance aggregrometry (Multiplate) after activation with thrombin receptor-activating peptide 6 (TRAP) and quantified by the area under the aggregation curve (AUC [aggregation units (AU)/min]). Scanning electron microscopy was performed to evaluate HyperHaes induced cell shape changes of thrombocytes.

Statistics: 2-way ANOVA for repeated measurements, Bonferroni post hoc test, p < 0.01.

Results

Dilution impaired whole blood coagulation and thrombocyte aggregation in all dilutions in a dose dependent fashion. In contrast to dilution with ISO and HS, respectively, dilution with HH as well as HT almost abolished coagulation (MCF_ExTEM from 57.3 ± 4.9 mm (native) to 1.7 ± 2.2 mm (HH 40% dilution; p < 0.0001) and to 6.6 ± 3.4 mm (HT 40% dilution; p < 0.0001) and thrombocyte aggregation (AUC from 1067 ± 234 AU/mm (native) to 14.5 ± 12.5 AU/mm (HH 40% dilution; p < 0.0001) and to 20.4 ± 10.4 AU/min (HT 40% dilution; p < 0.0001) without differences between HH and HT (MCF: p = 0.452; AUC: p = 0.449).

Conclusions

HH impairs platelet function during in vitro dilution already at 5% dilution. Impairment of whole blood coagulation is significant after 10% dilution or more. This effect can be pinpointed to the platelet function impairing hypertonic saline component and to a lesser extend to fibrin polymerization inhibition by the colloid component or dilution effects.

Accordingly, repeated administration and overdosage should be avoided.

Assessment of biochemical and hematological parameters in rats injected with Tityus serrulatus scorpion venom

The aim of this work was to evaluate the hematological changes induced by Tityus serrulatus venom (TsV). Blood of Wistar rats was collected 0.5, 2, 6 and 24 h after i.p. injection of TsV (0.5 mg/kg) or saline (controls). Two additional groups were injected with 0.67 mg/kg and 0.25 mg/kg of TsV and the blood was collected after 0.5 and 2 h, respectively. The results showed an increase on hematocrit (Ht), red blood cells (RBC) count, hemoglobin concentration (Hb), albumin and total protein, mainly 2-6 h after envenoming. Increase in serum activities of amylase, creatine kinase and aspartate aminotransferase were also observed, indicating tecidual damages. Hyperglycemia was observed at all times analyzed, as a consequence of catecholamine release. No significant changes were detected in the urea, [Na(+)] and [Ca(2+)], but an increase of [Mg(2+)], [K(+)] and conductivity was observed. TsV induced a reduction of erythrocytes osmotic fragility as consequence of dehydration and increase in plasma electrolytes concentration, as evidenced by its higher conductivity. This study demonstrated that TsV is able to induce severe hematological changes, that appear within the first hours after envenoming, justifying the seeking of medical attention as soon as possible to avoid worsening of clinical symptoms.

Early fluid resuscitation with hyperoncotic hydroxyethyl starch 200/0.5 (10%) in severe burn injury

Introduction

Despite large experience in the management of severe burn injury, there are still controversies regarding the best type of fluid resuscitation, especially during the first 24 hours after the trauma. Therefore, our study addressed the question whether hyperoncotic hydroxyethyl starch (HES) 200/0.5 (10%) administered in combination with crystalloids within the first 24 hours after injury is as effective as 'crystalloids only' in severe burn injury patients.

Methods

30 consecutive patients were enrolled to this prospective interventional open label study and assigned either to a traditional 'crystalloids only' or to a 'HES 200/0.5 (10%)' volume resuscitation protocol. Total amount of fluid administration, complications such as pulmonary failure, abdominal compartment syndrome, sepsis, renal failure and overall mortality were assessed. Cox proportional hazard regression analysis was performed for binary outcomes and adjustment for potential confounders was done in the multivariate regression models. For continuous outcome parameters multiple linear regression analysis was used.

Results

Group differences between patients receiving crystalloids only or HES 200/0.5 (10%) were not statistically significant. However, a large effect towards increased overall mortality (adjusted hazard ratio 7.12; P = 0.16) in the HES 200/0.5 (10%) group as compared to the crystalloids only group (43.8% versus 14.3%) was present. Similarly, the incidence of renal failure was 25.0% in the HES 200/0.5 (10%) group versus 7.1% in the crystalloid only group (adjusted hazard ratio 6.16; P = 0.42).

Conclusions

This small study indicates that the application of hyperoncotic HES 200/0.5 (10%) within the first 24 hours after severe burn injury may be associated with fatal outcome and should therefore be used with caution.

Trial registration

NCT01120730.

The role of pre-hospital blood gas analysis in trauma resuscitation

Background

To assess, whether arterial blood gas measurements during trauma patient's pre-hospital shock resuscitation yield useful information on haemodynamic response to fluid resuscitation by comparing haemodynamic and blood gas variables in patients undergoing two different fluid resuscitation regimens.

Methods

In a prospective randomised study of 37 trauma patients at risk for severe hypovolaemia, arterial blood gas values were analyzed at the accident site and on admission to hospital. Patients were randomised to receive either conventional fluid therapy or 300 ml of hypertonic saline. The groups were compared for demographic, injury severity, physiological and outcome variables.

Results

37 patients were included. Mean (SD) Revised Trauma Score (RTS) was 7.3427 (0.98) and Injury Severity Score (ISS) 15.1 (11.7). Seventeen (46%) patients received hypertonic fluid resuscitation and 20 (54%) received conventional fluid therapy, with no significant differences between the groups concerning demographic data or outcome. Base excess (BE) values decreased significantly more within the hypertonic saline (HS) group compared to the conventional fluid therapy group (mean BE difference -2.1 mmol/l vs. -0.5 mmol/l, p = 0.003). The pH values on admission were significantly lower within the HS group (mean 7.31 vs. 7.40, p = 0.000). Haemoglobin levels were in both groups lower on admission compared with accident site. Lactate levels on admission did not differ significantly between the groups.

Conclusion

Pre-hospital use of small-volume resuscitation led to significantly greater decrease of BE and pH values. A portable blood gas analyzer was found to be a useful tool in pre-hospital monitoring for trauma resuscitation.

Perioperative crystalloid and colloid fluid management in children: where are we and how did we get here?

It has been more than 50 yr since the landmark article in which Holliday and Segar (Pediatrics 1957;19:823-32) proposed the rate and composition of parenteral maintenance fluids for hospitalized children. Much of our practice of fluid administration in the perioperative period is based on this article. The glucose, electrolyte, and intravascular volume requirements of the pediatric surgical patient may be quite different than the original population described, and consequently, use of traditional hypotonic fluids proposed by Holliday and Segar may cause complications, such as hyperglycemia and hyponatremia, in the postoperative surgical patient. There is significant controversy regarding the choice of isotonic versus hypotonic fluids in the postoperative period. We discuss the origins of perioperative fluid management in children, review the current options for crystalloid fluid management, and present information on colloid use in pediatric patients.

The Toronto prehospital hypertonic resuscitation-head injury and multi organ dysfunction trial (TOPHR HIT)--methods and data collection tools

Background

Clinical trials evaluating the use of hypertonic saline in the treatment of hypovolemia and head trauma suggest no survival superiority over normal saline; however subgroup analyses suggest there may be a reduction in the inflammatory response and multiorgan failure which may lead to better survival and enhanced neurocognitive function. We describe a feasibility study of randomizing head injured patients to hypertonic saline and dextran vs. normal saline administration in the out of hospital setting.

Methods/Design

This feasibility study employs a randomized, placebo-controlled design evaluating normal saline compared with a single dose of 250 ml of 7.5% hypertonic saline in 6% dextran 70 in the management of traumatic brain injuries. The primary feasibility endpoints of the trial were: 1) baseline survival rates for the treatment and control group to aid in the design of a definitive multicentre trial, 2) randomization compliance rate, 3) ease of protocol implementation in the out-of-hospital setting, and 4) adverse event rate of HSD infusion.

The secondary objectives include measuring the effect of HSD in modulating the immuno-inflammatory response to severe head injury and its effect on modulating the release of neuro-biomarkers into serum; evaluating the role of serum neuro-biomarkers in predicting patient outcome and clinical response to HSD intervention; evaluating effects of HSD on brain atrophy post-injury and neurocognitive and neuropsychological outcomes.

Discussion

We anticipate three aspects of the trial will present challenges to trial success; ethical demands associated with a waiver of consent trial, challenging follow up and comprehensive accurate timely data collection of patient identifiers and clinical or laboratory values. In addition all the data collection tools had to be derived de novo as none existed in the literature.

Trial registration number

NCT00878631

Therapeutic small-volume resuscitation preserves pancreatic microcirculation in acute experimental pancreatitis of graded severity in rats

BACKGROUND

Microcirculatory disorders play a major part in the pathogenesis of acute pancreatitis. Improvement of microcirculation is hypothesized to open a therapeutic window. The aim of this study was to evaluate the effects of small-volume resuscitation in acute pancreatitis.

METHODS

In rats, acute pancreatitis of graded severity was induced and pancreatic microcirculation was observed in vivo with an epiluminescent microscope. Primary outcome measures were microcirculation, leukocyte adherence, concentration of trypsinogen-activating peptide, amylase activity and histopathologic tissue damage.

RESULTS

In necrotizing pancreatitis patients receiving prophylactic intervention with 7.5% hypertonic saline the functional capillary density was 76%. Postcapillary venular leukocyte adherence was 45% of vein cross-section. The median histopathologic damage scored 8 points. In controls, a complete microcirculatory breakdown was observed, and in the group with therapeutic intervention no significant difference was detected. In intermediate pancreatitis, the number of perfused capillaries remained 55.0 versus 23.3% in controls. Leukocyte adherence was 40.0 versus 51.7%. The histopathologic damage scored 6.0 versus 9.0 points. Trypsinogen-activating peptide concentration was reduced to 164 versus 402 nM in controls. In cerulein pancreatitis, the number of perfused capillaries was equally preserved in both groups.

CONCLUSION

Small-volume resuscitation preserves capillary microcirculation and prevents pancreatic injury in intermediate necrotizing pancreatitis.

Acid base and electrolyte changes after hypertonic saline (7.5%) infusion: A randomized controlled clinical trial

Hypertonic saline solutions are effective in the treatment of haemorrhagic and septic shock, elevated intracranial pressure and perioperative fluid deficits. Infusion, however, causes electrolyte and acid-base imbalance. In a randomized double-blind study, the effects of a 10-min infusion of 4 ml/kg 7.5% NaCl or 0.9% NaCl were evaluated in 14 fasting women before hysterectomy. Venous blood from the forearm was collected at baseline, 10, 20, 30, 60 and 120 min after start of the infusion for the determination of plasma electrolytes and acid-base balance. We found that 1) a median increase in plasma sodium of 11 mmol/l (range 9-13 mmol/l) and chloride of 14 mmol/l (range 9-16 mmol/l) immediately after the infusion followed by a small decrease after 2 h, 2) a minor decrease in plasma potassium in relation to the infusion followed by a significant increase of 0.3 mmol/l (range 0.1-1.4 mmol/l) above baseline after 1 h, 3) a decrease in pH of 0.05 (range 0.02-0.07) and, finally, 4) a decrease in base excess of 1.9 mmol/l (range 0.8-2.7 mmol/l). It is concluded that infusion of 7.5% NaCl in a clinical relevant dose increases plasma potassium and causes minor changes in the acid-base balance in normovolaemic women.

Oxidative stress decreases phosphatidylinositol 4,5-bisphosphate levels by deactivating phosphatidylinositol- 4-phosphate 5-kinase beta in a Syk-dependent manner

Phosphatidylinositol 4,5-bisphosphate (PIP(2)) has many essential functions and its homeostasis is highly regulated. We previously found that hypertonic stress increases PIP(2) by selectively activating the beta isoform of the type I phosphatidylinositol phosphate 5-kinase (PIP5Kbeta) through Ser/Thr dephosphorylation and promoting its translocation to the plasma membrane. Here we report that hydrogen peroxide (H(2)O(2)) also induces PIP5Kbeta Ser/Thr dephosphorylation, but it has the opposite effect on PIP(2) homeostasis, PIP5Kbeta function, and the actin cytoskeleton. Brief H(2)O(2) treatments decrease cellular PIP(2) in a PIP5Kbeta-dependent manner. PIP5Kbeta is tyrosine phosphorylated, dissociates from the plasma membrane, and has decreased lipid kinase activity. In contrast, the other two PIP5K isoforms are not inhibited by H(2)O(2). We identified spleen tyrosine kinase (Syk), which is activated by oxidants, as a candidate PIP5Kbeta kinase in this pathway, and mapped the oxidant-sensitive tyrosine phosphorylation site to residue 105. The PIP5KbetaY105E phosphomimetic is catalytically inactive and cytosolic, whereas the Y105F non-phosphorylatable mutant has higher intrinsic lipid kinase activity and is much more membrane associated than wild type PIP5Kbeta. These results suggest that during oxidative stress, as modeled by H(2)O(2) treatment, Syk-dependent tyrosine phosphorylation of PIP5Kbeta is the dominant post-translational modification that is responsible for the decrease in cellular PIP(2).

Hemodynamic effects of volume replacement with saline solution and hypertonic hydroxyethyl starch in dogs

PURPOSE: To investigate hemodynamic response to volume replacement with saline solution and hypertonic hydroxyethyl starch in hypovolemic dogs. METHODS: Forty dogs under general anesthesia and hemodynamic monitoring, following measurements at baseline, were bled 20 ml.Kg-1 and parameters were measured again after 10 minutes. The animals were randomly divided in two groups and volume replacement was performed with saline solution twice the volume removed or 4 ml.Kg-1 of hypertonic hydroxyethyl starch. Hemodynamic data were again measured after 5, 15, 30, 45 and 60 minutes. RESULTS: With both solutions values returned to satisfactory hemodynamic levels. With saline solution, there was a greater amplitude in variations that tended to decrease progressively. With hypertonic hydroxyethyl starch, the parameters studied returned more rapidly to levels similar to those at baseline and varied less. CONCLUSION: Both solutions proved to be efficient at replacing volume in the short period studied, although hypertonic hydroxyethyl starch produced more stable results.

[Traumatic thoracic aorta rupture: preclinical assessment, diagnosis and treatment options]

Traumatic aortic rupture is a life-threatening injury which is frequently associated with blunt thoracic trauma or found coincidentally in heavily traumatized patients. Depending on the degree of disruption of the damaged aortic wall, vascular injury is associated with a high primary mortality rate and a significant risk of secondary aortic rupture. Early clinical signs which may indicate a ruptured thoracic aorta are left sided thoracic pain, reduced ventilation, tachycardia and dyspnoe as well as hypotension in the lower extremities. The primary aim for emergency treatment is to maintain vital organ function and to hemodynamically stabilize the patient. Surgical treatment was previously performed by either direct aortic suture or segmental alloplastic graft interposition using the clamp and sew technique with or without extra-anatomic shunts or extracorporeal circulation. However, endovascular stent graft implantation has now become another treatment option for traumatic aortic rupture. According to the reported data and our own experience there is increasing evidence that endovascular aortic repair might become the treatment of choice for patients with traumatic aortic rupture, with the option of an early, less invasive intervention thus avoiding thoracotomy. Regular follow-up is necessary to detect possible stent graft migration or leakage which could require additional endovascular or open surgical re-interventions.

Exsanguination in trauma: A review of diagnostics and treatment options

Trauma patients with haemorrhagic shock who only transiently respond or do not respond to fluid therapy and/or the administration of blood products have exsanguinating injuries. Recognising shock due to (exsanguinating) haemorrhage in trauma is about constructing a synthesis of trauma mechanism, injuries, vital signs and the therapeutic response of the patient. The aim of prehospital care of bleeding trauma patients is to deliver the patient to a facility for definitive care within the shortest amount of time by rapid transport and minimise therapy to what is necessary to maintain adequate vital signs. Rapid decisions have to be made using regional trauma triage protocols that have incorporated patient condition, transport times and the level of care than can be performed by the prehospital care providers and the receiving hospitals. The treatment of bleeding patients is aimed at two major goals: stopping the bleeding and restoration of the blood volume. Fluid resuscitation should allow for preservation of vital functions without increasing the risk for further (re)bleeding. To prevent further deterioration and subsequent exsanguinations 'permissive hypotension' may be the goal to achieve. Within the hospital, a sound trauma team activation system, including the logistic procedure as well as activation criteria, is essential for a fast and adequate response. After determination of haemorrhagic shock, all efforts have to be directed to stop the bleeding in order to prevent exsanguinations. A simultaneous effort is made to restore blood volume and correct coagulation. Reversal of coagulopathy with pharmacotherapeutic interventions may be a promising concept to limit blood loss after trauma. Abdominal ultrasound has replaced diagnostic peritoneal lavage for detection of haemoperitoneum. With the development of sliding-gantry based computer tomography diagnostic systems, rapid evaluation by CT-scanning of the trauma patient is possible during resuscitation. The concept of damage control surgery, the staged approach in treatment of severe trauma, has proven to be of vital importance in the treatment of exsanguinating trauma patients and is adopted worldwide. When performing 'blind' transfusion or 'damage control resuscitation', a predetermined fixed ratio of blood components may result in the administration of higher plasma and platelets doses and may improve outcome. The role of thromboelastography and thromboelastometry as point-of-care tests for coagulation in massive blood loss is emerging, providing information about actual clot formation and clot stability, shortly (10min) after the blood sample is taken. Thus, therapy guided by the test results will allow for administration of specific coagulation factors that will be depleted despite administration with fresh frozen plasma during massive transfusion of blood components.

Effects of different resuscitation fluids on the rheologic behavior of red blood cells, blood viscosity and plasma viscosity in experimental hemorrhagic shock

BACKGROUND

Hemorrhagic shock is associated with severe rheological abnormalities. We hypothesized that in the setting of hemorrhagic shock, resuscitation can alter hemorheological characteristics dramatically, and different fluids cause different effects. The aim of this study was to investigate whether the type of fluid administered has an impact on hemorheological characteristics at the early stage of resuscitation in a rodent model of hemorrhagic shock.

METHODS

Animals were randomized into five groups: (1) sham hemorrhage (SHAM); (2) shock and sham resuscitation (SHOCK); (3) shock and resuscitation with normal saline 32 ml/kg (NS); (4) shock and resuscitation with 7.5% hypertonic saline 4 ml/kg (HS); (5) shock and resuscitation with 7.5% hypertonic saline/6% Dextran 70 4 ml/kg (HSD). Hemorheological characteristics were measured at 60 min after resuscitation.

RESULTS

Results showed that NS resuscitation deteriorated red blood cell (RBC) deformability compared with the SHOCK group. The HS group showed improved RBC deformability compared with the NS group, although the differences were not statistically significant. There were significant improvements of RBC deformability at all shear rates in the HSD group compared with the NS group. Whole blood and plasma viscosities decreased significantly in the SHOCK group compared with the SHAM group. At shear rates of 60 and 150 s(-1), the NS group decreased whole blood viscosity compared with the SHOCK group. The HSD group showed elevated plasma viscosity compared with the SHOCK, NS and HS groups.

CONCLUSION

These results suggested that at the early stage of hemorrhagic shock resuscitation, hypertonic-hyperoncotic resuscitation could improve RBC deformability compared with isotonic crystalloid resuscitation. Dextran 70 could elevate plasma viscosity to nearly baseline level. These effects of hypertonic-hyperoncotic resuscitation could be beneficial to maintain microcirculation.

Hypertonic saline reduces neutrophil-epithelial interactions in vitro and gut tissue damage in a mouse model of colitis

Transepithelial migration of polymorphonuclear neutrophils (PMN) plays a crucial role in inflammatory conditions of the intestine, such as inflammatory bowel diseases. Hypertonic saline (HS) exerts various inhibitory effects on PMN function. We hypothesized that HS could inhibit transepithelial migration of PMN and thereby prevent inflammatory events in experimental colitis. Isolated human PMN were treated with HS (40 mM), and their transmigration across a monolayer of T84 epithelial cells was induced by N-formyl-methionyl-leucyl-phenylalanine. Monolayer disruption was assessed by monitoring changes in transepithelial conductance in an Ussing chamber. Colitis in mice was induced by oral administration of dextran sulfate sodium (DSS). Animals were treated with 4 or 8 ml/kg of 7.5% saline intraperitoneally two times daily for 7 days. Controls received equivalent volumes of normal saline (NS, n = 6) or no intraperitoneal treatment (DSS, n = 12). The severity of inflammation was evaluated based on disease activity index and histology score. HS treatment of PMN in vitro significantly reduced cell migration and the disruption of T84 monolayers compared with untreated control cells (n = 5, P < 0.05). This effect of HS was dose dependent. HS treatment in vivo also reduced colitis-induced gut tissue damage, as indicated by an improved histology score compared with the NS and DSS groups. We conclude that HS inhibits transepithelial migration of PMN in vitro and gut tissue damage in vivo in a mouse model of colitis. Thus HS may have clinical value to reduce PMN-mediated intestinal damage.

Hypertonic saline solutions for treatment of intracranial hypertension

PURPOSE OF REVIEW

This review aims to provide an update on recent knowledge gained on hypertonic saline solutions for the treatment of intracranial hypertension. Explanatory approaches to the mechanisms underlying the edema-reducing effects of the solutions are outlined, practical aspects of use are presented, and trials that assessed their clinical utility are highlighted.

RECENT FINDINGS

With an established trauma system, hypertonic saline added to conventional fluid resuscitation did not improve long-term outcome in multiple injury with hypotension and brain trauma. In intensive care, hypertonic saline reduced intracranial hypertension after subarachnoid haemorrhage, brain trauma, and a variety of other brain diseases, including cerebral edema in acute liver failure.

SUMMARY

Hypertonic saline solutions have evolved as an alternative to mannitol or may be used in otherwise refractory intracranial hypertension to treat raised intracranial pressure. With high osmolar loads, the efficacy of the solution is enhanced, but no simple relationship between the saline concentration and the clinical effects of a solution is established. Caution is advised with high osmolar loads because they carry increased risks for potentially deleterious consequences of hypernatremia or may induce osmotic blood-brain barrier opening with possibly harmful extravasation of the hypertonic solution into the brain tissue.

Effects of hyperoncotic or hypertonic-hyperoncotic solutions on polymorphonuclear neutrophil count, elastase- and superoxide-anion production: a randomized controlled clinical trial in patients undergoing elective coronary artery bypass grafting

BACKGROUND

Hypertonic-hyperoncotic solutions may be an effective treatment for systemic inflammatory response syndrome (SIRS). With regard to the immunomodulatory effects of these drugs, previous studies demonstrated controversial results. Therefore, the present study investigated the influence of different hyperoncotic and hypertonic-hyperoncotic solutions on polymorphonuclear neutrophil leukocyte (PMNL) count, elastase and superoxide-anion production in patients undergoing elective coronary artery bypass grafting (CABG) with cardiopulmonary bypass.

METHODS

Fifty patients scheduled for elective CABG with cardiopulmonary bypass were randomly assigned to five groups: (i) NaCl 0.9%, 750 ml/m(2) body surface area (BSA); (ii) hydroxyethylic starch 10%, 250 ml/m(2) BSA and NaCl 0.9%, 400 ml/m(2) BSA; (iii) dextran 10%, 250 ml/m(2) BSA and NaCl 0.9%, 300 ml/m(2) BSA; (iv) hypertonic sodium chloride 7.2%/hyperoncotic hydroxyethylic starch 10%, 150 ml/m(2) BSA; and (v) hypertonic sodium chloride 7.2%/hyperoncotic dextran 10%, 150 ml/m(2) BSA. Blood samples were drawn from arterial, central venous and coronary artery sinus catheters peri-operatively. PMNL count, superoxide-anion production and elastase were recorded.

RESULTS

PMNL counts and elastase activity increased in all groups after reperfusion. Superoxide-anion production showed only minor changes. Between groups, no significant differences were demonstrated.

CONCLUSIONS

Infusion of clinically relevant doses of hypertonic-hyperoncotic solution did not affect PMNL count, elastase- or superoxide-anion production during elective CABG with cardiopulmonary bypass.

Use of Nuclear Magnetic Resonance Spectroscopy to Assess Renal Dysfunction After Hypertonic-Hyperoncotic Resuscitation in Rats

BACKGROUND

The aim of this study was to evaluate the renal tolerance of a hypertonic-hyperoncotic solution (HHS) administration during uncontrolled hemorrhagic shock (UHS).

METHODS

UHS was produced in rats by a preliminary bleed followed by tail amputation. Hydroxyethylstarch (HHS) 200/0.5 6% in NaCl 7.2% was administered to the HHS groups (n = 20) and normal saline (NS) to the NS group (n = 20). Infusion rates were adjusted to prevent mean arterial pressure (MAP) from falling either below 40 mm Hg in the HHS40 (n = 10) and NS40 groups (n = 10), or below 80 mm Hg in the HHS80 (n = 10) and NS80 groups (n = 10). Data obtained were compared with a sham group and a no resuscitation (NR) group. Nephrotoxicity was evaluated by nuclear magnetic resonance analysis in urine samples.

RESULTS

Survival was 60% in the NS40 group and 40% in the NS80 group, 70% in the HHS40 group, and 60% in the HHS80 group (p = not significant). Within and between target groups of 40 mm Hg MAP and 80 mm Hg MAP, there was no significant difference in survival. The mean values of renal metabolites to creatinine (ct) ratios were not significantly different among the six groups. Principal component analysis showed that the HHS80 group was characterized by an increase in allantoin/ct and urea/ct ratios demonstrating acute renal dysfunction and failure of nitrogen metabolism.

CONCLUSION

In prolonged UHS, an infusion of HHS may not increase the rate of survival. HHS infusion in normotensive resuscitation appears to be associated with renal toxicity.

Optimizing intraoperative fluid therapy

PURPOSE OF REVIEW

Correcting the fluid status of the surgical patient is an integral part of good anaesthetic practice. There have been few areas in anaesthesia and perioperative medicine as controversial as fluid resuscitation. Uncertainties still exist as to what the best solution to give is, whether it be a colloid or a crystalloid, and how and when to give it. As well as increasing awareness of the different properties of various colloids, there has been interest in the nature of the carrier solutions, essentially a choice between saline or Ringer's lactate (compound sodium lactate or Hartmann's solution). In this article we review recent studies involving crystalloids, the 'new colloids', and on the amount and timing of fluid therapy.

RECENT FINDINGS

Saline based fluids (including most colloids) are associated with a hyperchloremic metabolic acidosis, and a hypocoagulable state, although these may not necessarily harm the patient. Saline may have deleterious effects on renal function. Colloids in solutions similar to Ringer's lactate ('balanced solutions') may avoid these effects although few are currently available. Several studies that have used fluids (along with other therapies) to improve organ perfusion around the time of surgery have been associated with a better outcome.

SUMMARY

Compared with Ringer's lactate, saline, and saline-based colloids are associated with a hyperchloremic metabolic acidosis, and a hypocoagulable state although they may not be associated with adverse patient outcomes. Increasing awareness of the 'Stewart hypothesis' has led to new ways of managing hyperchloremic metabolic acidosis. The 'crystalloid-colloid debate' continues, and has led to an awareness that these different fluids, along with their carrier solutions are drugs with different effects. Several studies, in which patients have received more fluid in the protocol group, have found better clinical outcomes in the 'optimized' patients.

VASOPRESSIN MEDIATES THE PRESSOR EFFECT OF HYPERTONIC SALINE SOLUTION IN ENDOTOXIC SHOCK

The administration of lipopolysaccharide (LPS) to experimental animals results in a septic shock-like syndrome characterized by hypotension, and the hemodynamic management includes the restoration of adequate tissue perfusion by administration of resuscitation fluids to achieve an effective circulating volume. In the present study, we sought to investigate the effects of hypertonic saline solution administration on vasopressin secretion and mean arterial pressure in endotoxic shock. The pressor response to isotonic saline solution (0.9% sodium chloride) or hypertonic saline (7.5% sodium chloride, 4 mL/kg i.v.) was evaluated 4 h after LPS (1.5 mg/kg) administration. At this moment, plasma vasopressin did not differ from control; however, the blood pressure was lower in the LPS-treated group. The hypertonic saline administration was followed by an immediate recovery of blood pressure and also by an increase in plasma vasopressin levels compared with isotonic saline solution. The vasopressin V1 receptor antagonist (10 microg/kg, i.v., 5 min before infusion) blocked the pressor response to hypertonic saline solution. These data suggest that the recovery of blood pressure after hypertonic saline solution administration during endotoxic shock is mediated by vasopressin secretion.