The Effects of Albumin Versus Hydroxyethyl Starch Solution on Cardiorespiratory and Circulatory Variables in Critically III Patients

Assessing institutional responsibility in scientific misconduct: A case study of enoximone research by Joachim Boldt

BACKGROUND

Enoximone, a phosphodiesterase III inhibitor, was approved in Germany in 1989 and initially proposed for heart failure and perioperative cardiac conditions. The research of Joachim Boldt and his supervisor Gunter Hempelmann came under scrutiny after investigations revealed systematic scientific misconduct leading to numerous retractions. Therefore, early enoximone studies by Boldt and Hempelmann from 1988 to 1991 were reviewed.

METHODS

PubMed-listed publications and dissertations on enoximone from the Justus-Liebig-University of Giessen were analyzed for study design, participant demographics, methods, and outcomes. The data were screened for duplications and inconsistencies.

RESULTS

Of seven randomized controlled trial articles identified, two were retracted. Five of the non-retracted articles reported similarly designed studies and included similar patient cohorts. The analysis revealed overlap in patient demographics and reported outcomes and inconsistencies in cardiac index values between trials, suggesting data duplication and manipulation. Several other articles have been retracted. The analysis results of misconduct and co-authorship of retracted studies during Boldt's late formative years indicate inadequate mentorship. The university's slow response in supporting the retraction of publications involving scientific misconduct indicates systemic oversight problems.

CONCLUSION

All five publications analyzed remained active and warrant retraction to maintain the integrity of the scientific record. This analysis highlights the need for improved institutional supervision. The current guidelines of the Committee on Publication Ethics for retraction are inadequate for large-scale scientific misconduct. Comprehensive ethics training, regular audits, and transparent reporting are essential to ensure the credibility of published research.

Human albumin solutions in intensive care: A review

Albumin plays a key role in the critically ill patient acting as a prognostic marker and as a therapy in the form of human albumin solutions. However, the use of human albumin solution has varied over time with notable differences between health systems. Whilst its use is widely accepted for some clinical indications, its role has not always been clear in the critically ill and has been found to be harmful in some cohorts. Numerous studies have showed conflicting results and critical care clinicians have not always been guided by robust evidence. Nonetheless, at present the use of human albumin solution appears to be increasing again in the United Kingdom. Below, we discuss the latest evidence base for its use in critically ill patients.

Prevention of Acute Renal Failure - Fluid Repletion and Colloids

Hypovolemia alone or in conjunction with other factors is a main reason for acute renal failure in critically ill patients. Various crystalloid and colloid solutions are available to correct hypovolemia. Some of them have been implicated in impairment of renal function. Infusion of large amounts of sodium chloride is associated with increased incidence of nausea, vomiting and hyperchloremic metabolic acidosis. While gelatins and HES are preferred colloids in patients with normal kidney function, there is some evidence that the latter are associated with impaired renal function in patients with pre-existing kidney disease. Any hyperoncotic colloid given in large amounts may decrease glomerular filtration, and should therefore be combined with crystalloids.

Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016

OBJECTIVE

To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012."

DESIGN

A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The panel consisted of five sections: hemodynamics, infection, adjunctive therapies, metabolic, and ventilation. Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low, and to formulate recommendations as strong or weak, or best practice statement when applicable.

RESULTS

The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations, and 18 were best-practice statements. No recommendation was provided for four questions.

CONCLUSIONS

Substantial agreement exists among a large cohort of international experts regarding many strong recommendations for the best care of patients with sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality.

Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016

OBJECTIVE

To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012".

DESIGN

A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The panel consisted of five sections: hemodynamics, infection, adjunctive therapies, metabolic, and ventilation. Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low, and to formulate recommendations as strong or weak, or best practice statement when applicable.

RESULTS

The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations, and 18 were best-practice statements. No recommendation was provided for four questions.

CONCLUSIONS

Substantial agreement exists among a large cohort of international experts regarding many strong recommendations for the best care of patients with sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality.

The Management of Sepsis: A Practical Review

The incidence of the sepsis syndrome has increased dramatically in the last few decades. During this time we have gained new insights into the pathophysiologic mechanisms leading to organ dysfunction in sepsis and the importance of the host-bacterial interactions in mediating many of these processes. This knowledge has led to new therapeutic approaches and the investigation of a number of novel agents. An assessment of these approaches is presented to aid clinicians in the management of patients with severe sepsis. Criteria used to select studies included their relevance to the management of sepsis and their pertinence to clinicians. Appropriate antibiotic selection and volume resuscitation remain the cornerstone of treatment of septic patients. Hydroxyethyl starch solutions have theoretical advantages over crystalloids; there is, however, no data that the type of resuscitation fluid alters outcome. Vasoactive agents are required in patients who remain hemodynamically unstable or have evidence of tissue hypoxia after adequate volume resuscitation. Although dopamine is widely used, dobutamine and norepinephrine are our vasoactive agents of choice. Dopamine has no proven role in oliguric patients, with early dialysis recommended in patients with acute renal failure. The preferred method of renal replacement therapy remains to be determined. Blood products should be used cautiously in patients with disseminated intravascular coagulation. Therapeutic strategies that interfere with the immune system have not been proven to improve the outcome in unselected groups of patients. However, immunomodulation may prove to have a role in select subgroups of patients. Antibiotic therapy and intensive physiological support continues to be the main approach to the management of patients with severe sepsis. Despite the development of numerous novel therapeutic agents, these drugs have not been demonstrated to improve patient outcome.

Prevention of post-traumatic clinical capillary leak syndrome

Systemic capillary leak is an early feature of the inflammatory response to localized injury, and is proportional to the severity of the inflammatory insult. Loss of local control of inflammation leads to an exaggerated systemic inflammatory response known as systemic inflammatory response syndrome (SIRS). SIRS is associated with multiple organ failure and death when there is failure to maintain homeostasis.

Whilst the application of molecular biology and recombinant techniques have produced major advances in our understanding of the mediation of the inflammatory response, there is no agent currently available which will prevent SIRS and reduce the incidence of post-traumatic multiple organ failure. In the meantime, a more practical approach to the avoidance of SIRS and its attendant capillary leak syndrome is to attempt to reduce the deleterious effects of interstitial oedema by tailoring treatment to the rapid changes in capillary permeability.

Albumin: friend or foe?

In the absence of red blood cells or any other colloid, human albumin has saved thousands of lives since its first use in 1941. However, for general volume expansion purposes including trauma resuscitation, published evidence suggests that albumin has now been superseded by synthetic colloids, which are more effective volume expanders, have vascular protective effects and are cheaper.

Crystalloids and colloids for volume replacement

For many years there has been a debate about whether crystalloids or colloids should be used for resuscitation. Some years ago, albumin was the gold standard against which all other solutions were compared. This continues to be the case, despite the fact that other solutions are as effective for volume replacement. This paper stresses the need for a proper understanding of the properties of solutions that may influence the choice for volume replacement. Different classes of solutions are discussed in detail, with special reference to their effects on cardiovascular and oxygen transport parameters. Other important properties such as side-effects and effect on coagulation are also considered.

Meta-analysis of colloids versus crystalloids in critically ill, trauma and surgical patients

Background

There is uncertainty regarding the safety of different volume replacement solutions. The aim of this study was systematically to review evidence of crystalloid versus colloid solutions, and to determine whether these results are influenced by trial design or clinical setting.

Methods

PubMed, Embase and the Cochrane Central Register of Controlled Trials were used to identify randomized clinical trials (RCTs) that compared crystalloids with colloids as volume replacement solutions in patients with traumatic injuries, those undergoing surgery and in critically ill patients. Adjusted odds ratios (ORs) for mortality and major morbidity including renal injury were pooled using fixed-effect and random-effects models.

Results

Some 59 RCTs involving 16 889 patients were included in the analysis. Forty-one studies (69 per cent) were found to have selection, detection or performance bias. Colloid administration did not lead to increased mortality (32 trials, 16 647 patients; OR 0·99, 95 per cent c.i. 0·92 to 1·06), but did increase the risk of developing acute kidney injury requiring renal replacement therapy (9 trials, 11 648 patients; OR 1·35, 1·17 to 1·57). Sensitivity analyses that excluded small and low-quality studies did not substantially alter these results. Subgroup analyses by type of colloid showed that increased mortality and renal replacement therapy were associated with use of pentastarch, and increased risk of renal injury and renal replacement therapy with use of tetrastarch. Subgroup analysis indicated that the risks of mortality and renal injury attributable to colloids were observed only in critically ill patients with sepsis.

Conclusion

Current general restrictions on the use of colloid solutions are not supported by evidence.

Tiny tweaks, big changes: An alternative strategy to empower ethical culture of human research in anesthesia (A Taiwan Acta Anesthesiologica Taiwanica-Ethics Review Task Force Report)

For this guidance article, the Ethics Review Task Force (ERTF) of the Journal reviewed and discussed the ethics issues related to publication of human research in the field of anesthesia. ERTF first introduced international ethics principles and minimal requirements of reporting of ethics practices, followed by discussing the universal problems of publication ethics. ERTF then compared the accountability and methodology of several medical journals in assuring authors' ethics compliance. Using the Taiwan Institutional Review Board system as an example, ERTF expressed the importance of institutional review board registration and accreditation to assure human participant protection. ERTF presented four major human research misconducts in the field of anesthesia in recent years. ERTF finally proposed a flow-chart to guide journal peer reviewers and editors in ethics review during the editorial process in publishing. Examples of template languages applied in the Ethics statement section in the manuscript are expected to strengthen the ethics compliance of the authors and to set an ethical culture for all the stakeholders involved in human research.

Colloids in sepsis: evenly distributed molecules surrounded by uneven questions

Colloids are frequently used for fluid expansion in the intensive care unit, although its use on several clinical scenarios remains unproven of any relevant clinical benefit. The purpose of this article was to carry out a narrative review regarding the safety and efficacy of colloids in patients with sepsis and septic shock, with emphasis on the most commonly used colloids, albumin and starches. Colloids are effective fluid expanders and are able to restore the hemodynamic profile with less total volume than crystalloids. These properties appear to be preserved even in patients with sepsis with increased capillary permeability. However, some colloids are associated with renal impairment and coagulation abnormalities. Starch use was associated with increased mortality in two large clinical trials. Also, starches probably have significant renal adverse effects and may be related to more need for renal replacement therapy in severe sepsis. Albumin is the only colloid that has been shown safe in patients with sepsis and that may be associated with improved outcomes on specific subpopulations. No trial so far found any robust clinical end point favoring colloid use in patients with sepsis. Because there is no proven benefit of the use of most colloids in patients with sepsis, its use should not be encouraged outside clinical trials. Albumin is the only colloid solution that has proven to be safe, and its use may be considered on hypoalbuminemic patients with sepsis. Nevertheless, there are no robust data to recommend routine albumin administration in sepsis. Starch use should be avoided in patients with sepsis because of the recent findings of a multicenter randomized study until further evidence is available.

Colloid solutions for fluid resuscitation in patients with sepsis: systematic review of randomized controlled trials

BACKGROUND

Colloids are widely used for fluid resuscitation in patients with sepsis. But the optimal type of fluid remains unclear.

OBJECTIVE

Our aim was to assess the effects on mortality and safety of different colloid solutions in patients with sepsis requiring volume replacement by examining direct comparisons of colloid solutions.

METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, China Biological Medicine Database, VIP Chinese Journals Database, and CNKI China National Knowledge Infrastructure Whole Article Database. Randomized clinical trials comparing different colloids in septic patients needing fluid resuscitation were selected.

RESULTS

Seventeen randomized clinical trials with a total 1281 participants met the inclusion criteria. Mortality was obtained in all trials. For intervention of albumin vs. hydroxyethyl starch solution (HES), the relative risk (RR) of death was 0.98 (95% confidence interval [CI] 0.74-1.30). For intervention of albumin vs. gelatin, the RR of death was 2.4 (95% CI 0.31-18.35). For intervention of gelatin vs. HES, the RR of death was 1.02 (95% CI 0.79-1.32). For the intervention of HES vs. dextran, the RR of death was 1.38 (95% CI 0.28-6.78). For the intervention of gelatin vs. dextran, RR of death was not estimable. For albumin vs. dextran, no trial was included. Four trials of intervention of albumin vs. HES recorded the change of severity score.

CONCLUSIONS

There is no evidence that one colloid solution is more effective and safer than another for fluid resuscitation in sepsis. The severity score is improved in HES, but the confidence intervals are wide.

Colloid solutions for fluid resuscitation

BACKGROUND

Colloids are widely used in the replacement of fluid volume. However, doubts remain as to which colloid is best. Different colloids vary in their molecular weight and therefore in the length of time they remain in the circulatory system. Because of this, and their other characteristics, they may differ in their safety and efficacy.

OBJECTIVES

To compare the effects of different colloid solutions in patients thought to need volume replacement.

SEARCH METHODS

We searched the Cochrane Injuries Specialised Register (searched 1 December 2011), the Cochrane Central Register of Controlled Trials 2011, issue 4 (The Cochrane Library); MEDLINE (Ovid) (1948 to November Week 3 2011); EMBASE (Ovid) (1974 to 2011 Week 47); ISI Web of Science: Science Citation Index Expanded (1970 to 1 December 2011); ISI Web of Science: Conference Proceedings Citation Index-Science (1990 to 1 December 2011); CINAHL (EBSCO) (1982 to 1 December 2011); National Research Register (2007, Issue 1) and PubMed (searched 1 December 2011). Bibliographies of trials retrieved were searched, and for the initial version of the review drug companies manufacturing colloids were contacted for information (1999).

SELECTION CRITERIA

Randomised controlled trials comparing colloid solutions in critically ill and surgical patients thought to need volume replacement.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data and assessed the quality of the trials. The outcomes sought were death, amount of whole blood transfused, and incidence of adverse reactions.

MAIN RESULTS

Eighty-six trials, with a total of 5,484 participants, met the inclusion criteria. Quality of allocation concealment was judged to be adequate in 33 trials and poor or uncertain in the rest.Deaths were reported in 57 trials. For albumin or plasma protein fraction (PPF) versus hydroxyethyl starch (HES) 31 trials (n = 1719) reported mortality. The pooled relative risk (RR) was 1.06 (95% confidence interval (CI) 0.86 to 1.31). When the trials by Boldt were removed from the analysis the pooled RR was 0.90 (95% CI 0.68 to 1.20). For albumin or PPF versus gelatin, nine trials (n = 824) reported mortality. The RR was 0.89 (95% CI 0.65 to 1.21). Removing the study by Boldt from the analysis did not change the RR or CIs. For albumin or PPF versus dextran four trials (n = 360) reported mortality. The RR was 3.75 (95% CI 0.42 to 33.09). For gelatin versus HES 22 trials (n = 1612) reported mortality and the RR was 1.02 (95% CI 0.84 to 1.26). When the trials by Boldt were removed from the analysis the pooled RR was 1.03 (95% CI 0.84 to 1.27). RR was not estimable in the gelatin versus dextran and HES versus dextran groups.Forty-one trials recorded the amount of blood transfused; however, quantitative analysis was not possible due to skewness and variable reporting. Twenty-four trials recorded adverse reactions, with two studies reporting possible adverse reactions to gel and one to HES.

AUTHORS' CONCLUSIONS

From this review, there is no evidence that one colloid solution is more effective or safe than any other, although the CIs were wide and do not exclude clinically significant differences between colloids. Larger trials of fluid therapy are needed if clinically significant differences in mortality are to be detected or excluded.

Colloid solutions for fluid resuscitation

BACKGROUND

Colloids are widely used in the replacement of fluid volume. However doubts remain as to which colloid is best. Different colloids vary in their molecular weight and therefore in the length of time they remain in the circulatory system. Because of this and their other characteristics, they may differ in their safety and efficacy.

OBJECTIVES

To compare the effects of different colloid solutions in patients thought to need volume replacement.

SEARCH METHODS

We searched the Cochrane Injuries Specialised Register (searched 1 Dec 2011), Cochrane Central Register of Controlled Trials 2011, issue 4 (The Cochrane Library); MEDLINE (Ovid) (1948 to November Week 3 2011); EMBASE (Ovid) (1974 to 2011 Week 47); ISI Web of Science: Science Citation Index Expanded (1970 to 1 Dec 2011); ISI Web of Science: Conference Proceedings Citation Index-Science (1990 to 1 Dec 2011); CINAHL (EBSCO) (1982 to 1 Dec 2011); National Research Register (2007, Issue 1) and PubMed (searched 1 Dec 2011). Bibliographies of trials retrieved were searched, and for the initial version of the review drug companies manufacturing colloids were contacted for information (1999).

SELECTION CRITERIA

Randomised controlled trials comparing colloid solutions in critically ill and surgical patients thought to need volume replacement.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data and assessed the quality of the trials. The outcomes sought were death, amount of whole blood transfused, and incidence of adverse reactions.

MAIN RESULTS

Ninety trials, with a total of 5678 participants, met the inclusion criteria. Quality of allocation concealment was judged to be adequate in 35 trials and poor or uncertain in the rest.Deaths were obtained in 61 trials. For albumin or PPF versus hydroxyethyl starch (HES) 32 trials (n = 1769) reported mortality. The pooled relative risk (RR) was 1.07 (95% CI 0.87 to 1.32). When the trials by Boldt were removed from the analysis the pooled RR was 0.90 (95% CI 0.68 to 1.20). For albumin or PPF versus gelatin, nine trials (n = 824) reported mortality. The RR was 0.89 (95% CI 0.65 to 1.21). Removing the study by Boldt from the analysis did not change the RR or confidence intervals. For albumin or PPF versus Dextran four trials (n = 360) reported mortality. The RR was 3.75 (95% CI 0.42 to 33.09). For gelatin versus HES 25 trials (n = 1756) reported mortality and the RR was 1.03 (95% CI 0.84 to 1.26). When the trials by Boldt were removed from the analysis the pooled RR was 1.04 (95% CI 0.85 to 1.27). RR was not estimable in the gelatin versus dextran and HES versus dextran groups.Forty five trials recorded the amount of blood transfused, however quantitative analysis was not possible due to skewness and variable reporting. Twenty-four trials recorded adverse reactions, with two studies reporting possible adverse reactions to Gel and one to HES.

AUTHORS' CONCLUSIONS

From this review, there is no evidence that one colloid solution is more effective or safe than any other, although the confidence intervals are wide and do not exclude clinically significant differences between colloids. Larger trials of fluid therapy are needed if clinically significant differences in mortality are to be detected or excluded.

Colloid solutions for fluid resuscitation

BACKGROUND

Colloids are widely used in the replacement of fluid volume. However doubts remain as to which colloid is best. Different colloids vary in their molecular weight and therefore in the length of time they remain in the circulatory system. Because of this and their other characteristics, they may differ in their safety and efficacy.

OBJECTIVES

To compare the effects of different colloid solutions in patients thought to need volume replacement.

SEARCH STRATEGY

We searched the Cochrane Injuries Group's specialised register, CENTRAL (2007, Issue 1), MEDLINE (1994 to March 2007), EMBASE (1974 to March 2007), and the National Research Register (2007, Issue 1). Bibliographies of trials retrieved were searched, and drug companies manufacturing colloids were contacted for information. The search was last updated in March 2007.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing colloid solutions in critically ill and surgical patients thought to need volume replacement. The outcomes measured were death, amount of whole blood transfused, and incidence of adverse reactions.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data and assessed the quality of the trials.

MAIN RESULTS

Seventy trials, with a total of 4375 participants, met the inclusion criteria. Quality of allocation concealment was judged to be adequate in 24 trials and poor or uncertain in the rest.Deaths were obtained in 46 trials. For albumin or PPF versus hydroxyethyl starch (HES) 25 trials (n = 1234) reported mortality. The pooled relative risk (RR) was 1.14 (95% CI 0.91 to 1.43). When the trials by Boldt are removed from the analysis the pooled RR was 0.97 (95% CI 0.70 to 1.35). For albumin or PPF versus gelatin, seven trials (n = 636) reported mortality. The RR was 0.97 (95% CI 0.68 to 1.39). For albumin or PPF versus Dextran four trials (n = 360) reported mortality. The RR was 3.75 (95% CI 0.42 to 33.09). For gelatin versus HES 18 trials (n = 1337) reported mortality and RR was 1.00 (95% CI 0.80 to 1.25). RR was not estimable in the gelatin versus dextran and HES versus dextran groups.Thirty-seven trials recorded the amount of blood transfused, however quantitative analysis was not possible due to skewness and variable reporting. Nineteen trials recorded adverse reactions, but none occurred.

AUTHORS' CONCLUSIONS

From this review, there is no evidence that one colloid solution is more effective or safe than any other, although the confidence intervals are wide and do not exclude clinically significant differences between colloids. Larger trials of fluid therapy are needed if clinically significant differences in mortality are to be detected or excluded.

The impact of fluid therapy on microcirculation and tissue oxygenation in hypovolemic patients: a review

PURPOSE

An optimal volume replacement strategy aims to restore systemic hemodynamics with the ultimate goals of improving organ perfusion and microcirculation for sustaining adequate tissue oxygenation. This review presents the (patho)physiological basis of hypovolemia, microcirculation, and tissue oxygenation and presents a literature review on the effects of plasma substitutes on microperfusion and oxygenation in the clinical setting.

METHODS

Literature review of the effects of fluid therapy on microcirculation and tissue oxygenation using PubMed search including original papers in English from 1988 to 2009.

RESULTS

We identified a total of 14 articles dealing with the effects of different crystalloids and colloids on organ perfusion, microcirculation, and tissue oxygenation in patients. The results are divergent, but there is a general trend that colloids are superior to crystalloids in improving organ perfusion, microcirculation, and tissue oxygenation. Due to the limited number of studies and different study conditions, a meta-analysis on the effects of the volume replacement strategies on microcirculation is not possible.

CONCLUSIONS

Improving the microcirculation by volume replacement appears to be a promising issue when treating the critically ill. The growing insights from animal experiments have to be translated into the clinical setting to identify the optimal fluid regimen for correcting hypovolemia. New techniques for monitoring microcirculation at the bedside might provide such endpoints, although these have to be validated also in the clinical setting. Whether improved microperfusion and tissue oxygenation by fluid therapy will also improve patient outcomes will have to be proven by future studies.

Resuscitation with hydroxyethyl starch solution prevents bone marrow mononuclear apoptosis in a rat trauma-hemorrhagic shock model

BACKGROUND

: Trauma-hemorrhagic shock (T/HS) has been associated with multiorgan dysfunction, including bone marrow failure. This study examined apoptosis and morphologic alterations in bone marrow mononuclear cells (BMMNCs) with different volume therapies after T/HS.

METHODS

: T/HS was induced in groups of male Sprague-Dawley rats through a fracture of the left femur and continual bleeding for 30 minutes, followed by resuscitation with Ringer's lactate solution (RL), 6% hydroxyethyl starch solution (HES), or 5% albumin (ALB). Mean arterial blood pressure was monitored during the T/HS and resuscitation, and the impacts of various resuscitative fluids on apoptosis and morphology of BMMNCs at 24 hours and 48 hours after resuscitation were examined using flow cytometry, transferase-mediated dUTP nick-end labeling assay, and hematoxylin and eosin staining.

RESULTS

: Fluctuations in mean arterial blood pressure were homogenous among the three treatment groups. The percentage of early BMMNC apoptosis increased significantly at 24 hours and 48 hours (24.65% +/- 5.41% and 29.09% +/- 2.07%, respectively; p < 0.05), and the percentage of late BMMNC apoptosis increased to 13.43% +/- 2.82% (p < 0.05) at 48 hours in the T/HS + RL group. In contrast, resuscitation with HES alone dramatically attenuated the apoptosis. Resuscitation with ALB alleviated BMMNC apoptosis, except for late apoptosis at 48 hours. A greater number of apoptotic BMMNCs as well as morphologic alterations were shown using the transferase-mediated dUTP nick-end labeling assay and hematoxylin and eosin stain in the T/HS + RL group than in the HES or ALB groups.

CONCLUSION

: Intravascular volume replacement with HES showed prevention of BMMNC apoptosis at first 48 hours after T/HS compared with RL and ALB. These findings provide new insights into the intervention mechanism of HES on T/HS-related multiorgan dysfunction.

Greater cardiac response of colloid than saline fluid loading in septic and non-septic critically ill patients with clinical hypovolaemia

BACKGROUND AND OBJECTIVE

The haemodynamics of crystalloid and colloid fluid loading may depend on underlying disease, i.e. sepsis versus non-sepsis.

DESIGN AND SETTING

A single-centre, single-blinded, randomized clinical trial was carried out on 24 critically ill sepsis and 24 non-sepsis patients with clinical hypovolaemia, assigned to loading with normal saline, gelatin 4%, hydroxyethyl starch 6% or albumin 5% in a 90-min (delta) central venous pressure (CVP)-guided fluid loading protocol. Transpulmonary thermodilution was done each 30 min, yielding, among others, global end-diastolic volume and cardiac indices (GEDVI, CI).

RESULTS

Sepsis patients had hyperdynamic hypotension in spite of myocardial depression and dilatation, and greater inotropic/vasopressor requirements than non-sepsis patients. Independent of underlying disease, CVP and GEDVI increased more after colloid than saline loading (P < 0.018), so that CI increased by about 2% after saline and 12% after colloid loading (P = 0.029). The increase in preload-recruitable stroke work was also greater with colloids and did not differ among conditions.

CONCLUSION

Fluid loading with colloids results in a greater linear increase in cardiac filling, output and stroke work than does saline loading, in both septic and non-septic clinical hypovolaemia, in spite of myocardial depression and presumably increased vasopermeability potentially decreasing the effects of colloid fluid loading in the former.

Effects of polygeline and hydroxyethyl starch solutions on liver functions assessed with LIMON in hypovolemic patients

BACKGROUND

Hypovolemia is a common clinical entity in critical patients, and adequate volume replacement therapy seems to be essential for maintaining tissue perfusion. However, it is still uncertain which solution is most appropriate for fluid resuscitation.

OBJECTIVE

The aim of this study was to investigate the effects of fluid resuscitation with 3.5% polygeline versus 6% hydroxyethyl starch solutions on hemodynamic functions and liver functions assessed with a noninvasive liver function monitoring system (LIMON) in hypovolemic patients.

DESIGN

This study is a prospective randomized clinical trial.

MEASUREMENTS AND RESULTS

Thirty hypovolemic patients (intrathoracic blood volume index, <850 mL/m(2)) were randomized into hydroxyethyl starch (mean molecular weight, 130,000 Da) and polygeline (mean molecular weight, 30,000 Da) groups (15 patients each). Indocyanine green plasma disappearance elimination (ICG-PDR) were conducted concurrently using LIMON. A dose of 0.3 mg/kg ICG was given through a cubital fossa vein as a bolus. For fluid resuscitation, 500 mL of colloid was given to the patients. Repeated hemodynamic and ICG-PDR measurements were done at baseline, after infusion, and then at 30 minutes after infusion.

RESULTS

Intrathoracic blood volume index and systolic, diastolic, and mean blood pressures increased significantly after infusion and remained elevated for 30 minutes after infusion, but there was no significant difference between the 2 groups. Indocyanine green plasma disappearance elimination values were similar in both groups with no significant difference between the two.

CONCLUSION

Increasing intrathoracic blood volume index and hemodynamic variables by fluid loading is not associated with a significant change in ICG-PDR.

Resuscitation with hydroxyethyl starch solution prevents CD4+ T-lymphocyte apoptosis and modulates the balance of T helper type 1 and T helper type 2 responses in the rat with traumatic virgule/shill hemorrhagic shock

Trauma/hemorrhagic shock (TH/S) has been associated with inflammation and immunodisorders, leading to immunosuppression, multiorgan dysfunction, and death. However, little is known about the effect of resuscitation with different solutions on the immunological function. To address this issue, groups of male Sprague-Dawley rats were induced with TH/S by fracture in the left femur and continual bleeding to keep the MAP of 30 +/- 5 mmHg for 30 min, followed by resuscitation with 6% hydroxyethyl starch solution (HES), Ringer's lactate solution (RS), or 5% albumin (ALB), and the impact of resuscitation on the activation, differentiation, and survival of CD4 T cells was longitudinally examined after TH/S and resuscitation. After resuscitation, the MAP, as expected, gradually increased regardless of the type of fluids transfused. The percentage of CD4+ T cells decreased to 20% to 25%, and the ratio of T helper type 1 (TH1)/TH2 responses was significantly reduced in all TH/S rats, however, resuscitation with HES alone reversed the trends (49.4% +/- 9.7% vs. 55.2% +/- 2.6% in sham for CD4 T cells; 0.64 +/- 0.23 vs. 0.71 +/- 0.16 in sham for the ratio of TH1/TH2, P > 0.05 for both). Treatment with HES or ALB, but not RS, prevented CD4 T-cell apoptosis (sham, 7.23% +/- 3.4%; HES, 10.2% +/- 4.1%; RS, 15.2% +/- 5.4%; ALB, 10.6% +/- 4.3%; 48 h) and nuclear factor-kappaB p65 activation (sham, 0.17 +/- 0.04; HES, 0.34 +/- 0.05; RS, 0.41 +/- 0.09; ALB, 0.25 +/- 0.09; 48 h) induced by TH/S early after resuscitation. These data demonstrated that HES resuscitation modulated the balance of TH1 and TH2 responses and inhibited TH/S-related nuclear factor-kappaB activation and CD4 T-cell apoptosis in TH/S rats. Our findings provide new insights into understanding the TH/S-related immunodisorders and may aid in the design of new therapy for intervention of TH/S.

Haemodynamics and Acid-Base Equilibrium after Cardiac Surgery: Comparison of Rapidly Degradable Hydroxythyl Starch Solutions and Albumin

Background:

Stable haemodynamics is often achieved by administration of colloids after cardiac surgery. We conducted a prospective, randomized, open-label study comparing haemodynamics and acid-base equilibrium after infusion of two rapidly degradable hydroxyethyl starch (HES) solutions or human albumin (HA) to cardiac surgical patients.

Materials and Methods:

45 patients received a predetermined fixed dose of 15 ml kg−1 of either 6% HES (MW 130 kDa, n=15), 6% HES (MW 200 kDa, n=15) or 4% HA (MW 69 kDa, n=15) after on-pump cardiac surgery.

Results:

Left ventricular filling pressures assessed using pulmonary artery catheter responded similarly in all groups. Mean (SD) cardiac index was higher in HES130 [3.5 1 min−1 m−2 (0.7)] and HES200 [3.5 1 min−1 m−2 (0.5)] than in HA [2.8 1 min−1 m−2 (0.6)] group after completion of infusion (P=0.002) but no differences were detected at 2 and 18 hours. Oxygen delivery increased in both HES groups but not in HA group. After cessation of infusion base excess was the most negative in HA group. At 2 hours mean (SD) base excess was higher in HWS130 [0 (1.32)] than in HES200 [-1.32 (2.27)] and HA [-2.3 (1.3)] group (P=0.002, between the groups).

Conclusions:

We conclude that the effect of albumin on cardiac performance is inferior than that of HES130 or HES200 in early postoperative phase after cardiac surgery. HES130 induces no alterations in acid-base equilibrium whereas a negative base excess was observed after HA infusion.

Colloid solutions for fluid resuscitation

BACKGROUND

Colloids are widely used in the replacement of fluid volume. However doubts remain as to which colloid is best. Different colloids vary in their molecular weight and therefore in the length of time they remain in the circulatory system. Because of this and their other characteristics, they may differ in their safety and efficacy.

OBJECTIVES

To compare the effects of different colloid solutions in patients thought to need volume replacement.

SEARCH STRATEGY

We searched the Cochrane Injuries Group specialised register, CENTRAL (2007, Issue 1), MEDLINE (1994 to March 2007), EMBASE (1974 to March 2007), and the National Research Register (2007, issue 1). Bibliographies of trials retrieved were searched, and drug companies manufacturing colloids were contacted for information. The search was last updated in March 2007.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing colloid solutions in critically ill and surgical patients thought to need volume replacement. The outcomes measured were death, amount of whole blood transfused, and incidence of adverse reactions.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data and assessed the quality of the trials.

MAIN RESULTS

Seventy trials, with a total of 4375 participants, met the inclusion criteria. Quality of allocation concealment was judged to be adequate in 24 trials and poor or uncertain in the rest. Deaths were obtained in 46 trials. For albumin or PPF versus hydroxyethyl starch (HES) 25 trials (n = 1234) reported mortality. The pooled relative risk (RR) was 1.14 (95% CI 0.91 to 1.43). For albumin or PPF versus gelatin, seven trials (n = 636) reported mortality. The RR was 0.97 (95% CI 0.68 to 1.39). For albumin or PPF versus Dextran four trials (n = 360) reported mortality. The RR was 3.75 (95% CI 0.42 to 33.09). For gelatin versus HES 18 trials (n = 1337) reported mortality and RR was 1.00 (95% CI 0.80 to 1.25). RR was not estimable in the gelatin versus dextran and HES versus dextran groups.Thirty-seven trials recorded the amount of blood transfused, however quantitative analysis was not possible due to skewness and variable reporting. Nineteen trials recorded adverse reactions, but none occurred.

AUTHORS' CONCLUSIONS

From this review, there is no evidence that one colloid solution is more effective or safe than any other, although the confidence intervals are wide and do not exclude clinically significant differences between colloids. Larger trials of fluid therapy are needed if clinically significant differences in mortality are to be detected or excluded.

Urosepsis: from the intensive care viewpoint

A recent survey conducted by the Competence Network Sepsis (SepNet) revealed that severe sepsis and/or septic shock occurs in 75000 inhabitants (110 per 100,000) and sepsis occurs in 79000 inhabitants (116 per 100,000) in Germany annually. The prevalence of urosepsis in this survey was 7%. Early diagnosis of sepsis prior to the onset of clinical deterioration is of particular interest because this would increase the possibility of early and specific treatment, which in turn is the major determining factor of mortality in septic patients. Treatment of urosepsis consists of source control, early antimicrobial therapy as well as supportive and adjunctive therapy. For supportive therapy, adequate volume loading is the most important step in the treatment of patients with urosepsis in order to restore and maintain oxygen transport and tissue oxygenation. Therefore, supportive treatment should focus on adequate volume resuscitation and appropriate use of inotropes/vasopressors. The PROWESS study is the first investigation demonstrating the decrease in mortality in patients with sepsis following administration of activated protein C (APC). Thus, administration of APC to patients with two-organ failure or an APACHE II score > or =25 within the first 24 h after the first sepsis-induced organ failure is a part of adjunctive therapy. Additionally, current data support low-dose hydrocortisone therapy in patients with vasopressor-dependent severe septic shock. Time to initiation of therapy is crucial for surviving sepsis. Implementing new medical evidence in this context into daily clinical intensive care remains a major hurdle.

Plasma colloid osmotic pressure and total protein in horses during colic surgery

OBJECTIVE

To assess the changes in colloid osmotic pressure (COP) in horses undergoing surgery for colic.

STUDY DESIGN

Prospective clinical evaluation.

ANIMALS

Twenty-nine adult horses presented for emergency laparotomy.

METHODS

Horses were premedicated with intravenous (IV) xylazine and anesthesia was induced with ketamine, diazepam and guaifenesin and was maintained with isoflurane as required. Lactated Ringer's solution (LRS) was given to all horses during anesthesia. Blood was collected in heparin before, and every 30 minutes during, anesthesia to measure COP, total protein concentration (TP), osmolality, packed cell volume, electrolytes, glucose and lactate. In addition, COP was estimated using different formulas previously described for horses.

RESULTS

Before anesthesia, COP and TP were 18.7 +/- 2.2 mmHg (2.49 +/- 0.29 kPa) and 6.3 +/- 0.7 g dL(-1), respectively. The horses received a mean +/- SD of 19.5 +/- 3.9 mL kg(-1) hour(-1) (range 15-25 mL kg(-1)hour(-1)) of LRS during anesthesia. The COP and TP decreased linearly (R(2) = 0.99, p < 0.01) during anesthesia and reached the lowest point at the end of anesthesia with a COP of 11.6 +/- 1.6 mmHg (1.55 +/- 0.21 kPa) and TP of 4.4 +/- 0.4 g dL(-1). The Pearson correlation coefficient for COP versus TP was r(2) = 0.78. Calculation of COP from TP concentrations showed that two formulas could predict COP to within 1 mmHg (0.13 kPa) (Thomas & Brown 1992; Boscan et al. 2007).

CONCLUSIONS AND CLINICAL RELEVANCE

Colloid osmotic pressure, like TP, decreased greatly over the course of crystalloid fluid infusion during anesthesia for laparotomy in horses with colic. This change may predispose the animal to tissue edema with subsequent morbidity.

Safety and efficacy of albumin administration in trauma

Albumin is one of the oldest known and studied human proteins. It is characterised by diverse physiological and biochemical properties that render it relevant to many aspects of the disordered vascular and cellular functions after trauma. Apart from the ability to maintain the colloid oncotic pressure, human serum albumin has multiple effects, including antioxidant activity and binding affinity for drugs and toxic substances, inhibition of apoptosis and modulation of trauma-induced inflammatory response. According to the current state of knowledge, there are conflicting results regarding the benefits of albumin administration in critically ill patients. Further investigations are warranted to resolve the continued uncertainty about the safety and efficacy of human serum albumin in specific clinical circumstances and selected populations of severely injured patients.

Plasma colloid osmotic pressure and total protein trends in horses during anesthesia1

OBJECTIVE

To investigate the changes in colloid osmotic pressure (COP) and total protein concentrations during routine general anesthesia in horses.

STUDY DESIGN

Prospective, clinical study.

ANIMALS

Twelve adult healthy horses aged 9.1 +/- 4.7 years and weighing 474 +/- 79 kg presented for elective surgery and 14 adult horses aged 8.7 +/- 7.3 years and weighing 510 +/- 85 kg.

METHODS

All horses were premedicated with xylazine and anesthesia induced with ketamine, diazepam and guaifenesin, and maintained with isoflurane for 2.5 hours. Lactate Ringer's solution was administered at 11 mL kg(-1) hour(-1). Osmolality, COP, electrolytes, glucose, and lactate were measured with specific commercial analyzers. Total protein (TP) was determined with a refractometer and packed cell volume with centrifuged capillary tubes. In the second group of 14 horses samples were taken from both venous and arterial sites simultaneously and the above measurements performed.

RESULTS

Before anesthesia, COP and TP were 22.2 +/- 2 mmHg and 6.9 +/- 0.4 g dL(-1), respectively. Within 15 minutes of anesthetic induction, COP and TP decreased significantly (19.9 +/- 1.9 mmHg and 6.3 +/- 1.9 g dL(-1); p < 0.01). During anesthesia COP and TP decreased in a linear form (COP r2 = 0.96 and TP r2 = 0.97). The COP and TP were 15 +/- 1.3 mmHg and 5.1 +/- 0.2 g dL(-1) at the end of anesthesia. Calculation of COP from TP values failed to accurately predict measured COP. Simultaneous arterial and venous samples in the 14 anesthetized horses yielded no differences for COP or TP.

CONCLUSIONS AND CLINICAL RELEVANCE

The data indicate that COP, like TP, decreases over the course of routine anesthetic management of horses and venous versus arterial samples should reveal comparable information.

FLUID RESUSCITATION IN SEVERE SEPSIS AND SEPTIC SHOCK

The aim of this study was to investigate whether the type of i.v. fluid administered has an impact on outcome in an animal model of septic shock. The study included 28 anesthetized, invasively monitored, mechanically ventilated female sheep (29.5 +/- 4.0 kg), which received 0.5 g/kg body weight of feces into the abdominal cavity to induce peritonitis. During the surgical operation and 4 h after feces spillage, only Ringer's lactate (RL) was administered in all animals. Thereafter, animals were randomized to receive continuous infusions of RL (n = 7) alone or combined with either 20% albumin (n = 7, volume ratio to RL 1:10) or 6% hydroxyethyl starch (HES) (n = 7, volume ratio to RL 1:1), or gelatin alone (n= 7, no volume limitation). Fluid resuscitation was titrated to maintain pulmonary artery occlusion pressure at baseline levels throughout the experiment. No antibiotics or vasoactive drugs were administered, and animals were monitored until their spontaneous death. Hemodynamic variables were better with HES and albumin than with the other fluids, as reflected by higher stroke volume, cardiac index, and oxygen delivery (all P < 0.05). Hydroxyethyl-starch-treated animals also had lower arterial lactate concentrations (P < 0.01). However, times to develop hypotension and oliguria were similar in all groups. Blood interleukin (IL) 6 concentrations were significantly increased in all groups. The mean survival time was similar in all groups. In this clinically relevant model of prolonged septic shock, albumin and HES solution resulted in higher cardiac output, oxygen delivery, and lower blood lactate levels than gelatin and RL; however, the choice of i.v. fluid did not affect outcome.

Clinical experience of hydroxyethyl starch (10% HES 200/0.5) in cerebral perfusion pressure protocol for severe head injury

BACKGROUND

The present study was undertaken to evaluate 10% hydroxyethyl starch (HES 200/0.5) with regard to its clinical outcome and safety in the treatment of severe head injury.

METHODS

Retrospective review of patient data from a prospectively designed standard treatment protocol for severe head injury. The standard protocol included (1) cerebral perfusion pressure higher than 60 mm Hg, (2) colloid solution (10% HES 200/0.5) 1000 mL/d in combination with crystalloid solution, (3) stepwise management of intracranial hypertension. Renal function, coagulation function, and electrolytes were evaluated every other day. The data of intracranial pressure, mean arterial pressure, cerebral perfusion pressure, intake, output, mannitol, complications, and outcome were recorded and analyzed.

RESULTS

There were 78 patients, aged 45.61 +/- 21.80 years, in this study. The initial Glasgow Coma Scale score was 6.35 +/- 1.38. Seventy-three patients received operations with intracranial pressure monitoring. Blood transfusion was surgery related (days 1 and 2); otherwise, it was rarely used (P<.05). Prolonged prothrombin time was shown only 7 (2.65%) times of 234 of blood sampling. There was no anaphylactic reaction, pulmonary complications, or renal function deterioration in the course of our observation. The chart review of the patients at 6 months revealed the following: favorable outcome, 55.1%; unfavorable outcome, 33.3%; and mortality, 11.6%.

CONCLUSIONS

The 10% HES (200/0.5) can be used in the treatment protocol of severe head injury. There is no definite bleeding complications documented by current dosage of HES. Besides, balanced fluid management can be achieved without causing serious pulmonary complications. However, a further randomized, prospective study is needed to define the actual benefit of HES in fluid management and clinical outcome.

Plasma volume expansion and transcapillary fluid exchange in skeletal muscle of albumin, dextran, gelatin, hydroxyethyl starch, and saline after trauma in the cat*

OBJECTIVE

To compare 5% albumin, 6% dextran 70, 3.5% gelatin, 6% hydroxyethyl starch 130/0.4, and saline regarding their plasma volume expanding effect after a surgical skeletal muscle trauma and their simultaneous effects on transvascular fluid exchange in skeletal muscle.

DESIGN

Controlled, prospective, randomized laboratory study.

SETTING

University research laboratory.

SUBJECTS

Thirty-six adult cats.

INTERVENTIONS

Systemic arterial pressure and tissue volume variations of and blood flow to a surgically isolated and autoperfused calf muscle placed in a plethysmograph were recorded. Arterial and venous pressures to the muscle were kept constant. After preparation, plasma volumes were determined by a I albumin tracer technique just before and 3 hrs after a bolus infusion of the plasma expander (25 mL/kg).

MEASUREMENTS AND MAIN RESULTS

Plasma volume was 20.9 +/- 2.9 mL/kg (n = 36) just before infusion of the plasma expander (normal plasma volume for the cat is 34-37 mL/kg). The remaining volume expansion of the infusion after 3 hrs was 6.8 mL/kg for albumin, 11.2 mL/kg for dextran, 1.8 mL/kg for gelatin, 2.2 mL/kg for hydroxyethyl starch, and 0.9 mL/kg for saline. Plasma volume decreased by 1.1 mL/kg when no solution was given (n = 6 per group). Colloid osmotic pressure was better preserved with dextran and albumin than with the other solutions. Albumin and dextran reduced muscle volume by absorption after 3 hrs, whereas the initial absorption turned to net filtration in the gelatin and hydroxyethyl starch groups. Saline infusion increased muscle volume by filtration for about 20 mins, followed by an approximately constant volume.

CONCLUSION

The relatively poor plasma expansion for all solutions analyzed can most likely be explained by increased transcapillary leakage due to increased microvascular permeability following trauma. Under such circumstances, for equal volumes, plasma expansion was better preserved with 6% dextran 70 than with 5% albumin, which was better than 3.5% gelatin, 6% hydroxyethyl starch 130/0.4, and saline.

Extreme between-study homogeneity in meta-analyses could offer useful insights

OBJECTIVES

Meta-analyses are routinely evaluated for the presence of large between-study heterogeneity. We examined whether it is also important to probe whether there is extreme between-study homogeneity.

STUDY DESIGN

We used heterogeneity tests with left-sided statistical significance for inference and developed a Monte Carlo simulation test for testing extreme homogeneity in risk ratios across studies, using the empiric distribution of the summary risk ratio and heterogeneity statistic. A left-sided P=0.01 threshold was set for claiming extreme homogeneity to minimize type I error.

RESULTS

Among 11,803 meta-analyses with binary contrasts from the Cochrane Library, 143 (1.21%) had left-sided P-value <0.01 for the asymptotic Q statistic and 1,004 (8.50%) had left-sided P-value <0.10. The frequency of extreme between-study homogeneity did not depend on the number of studies in the meta-analyses. We identified examples where extreme between-study homogeneity (left-sided P-value <0.01) could result from various possibilities beyond chance. These included inappropriate statistical inference (asymptotic vs. Monte Carlo), use of a specific effect metric, correlated data or stratification using strong predictors of outcome, and biases and potential fraud.

CONCLUSION

Extreme between-study homogeneity may provide useful insights about a meta-analysis and its constituent studies.

Cardiac response is greater for colloid than saline fluid loading after cardiac or vascular surgery

OBJECTIVE

To study the effects on volume expansion and myocardial function of colloids or crystalloids in the treatment of hypovolaemic hypotension after cardiac and major vascular surgery.

DESIGN AND SETTING

A single-centre, single-blinded, randomized clinical trial at the intensive care unit of a university hospital.

PATIENTS AND METHODS

Patients (n=67) were subjected to a 90-min filling pressure-guided fluid challenge with saline 0.9% or the colloids gelatin 4%, hydroxyethyl starch 6% or albumin 5%. Biochemical variables and haemodynamics (transpulmonary thermodilution) were measured.

RESULTS

An amount of 1800 (1300-1800) ml of saline or 1600 (750-1800) ml of colloid solution (P< 0.005) was infused. Colloid osmotic pressure (COP) decreased in the saline group and increased in the colloid groups (P< 0.001). Plasma volume increased by 3.0% (-18 to 24) in the saline versus 19% (-11 to 50) in the colloid groups (P< 0.001). Cardiac index increased by median 13% (ns) in the saline group and by 22% in the colloid groups (P<0.005). The rise in left ventricular stroke work index was greater in the colloid than in the saline groups. The different colloids were equally effective. The rise in cardiac index related to the rise in plasma volume and global end-diastolic volume, confirming plasma volume and preload augmentation by the fluid loading.

CONCLUSION

After cardiac or major vascular surgery, the pressure- and time-guided fluid response is dependent on the type of fluid used. Colloid fluid loading leads to a greater increase in preload-recruitable cardiac and left ventricular stroke work indices than that with saline, because of greater plasma volume expansion following an increase in plasma COP.

Effects of hydroxyethyl starch 130/0.4 on pulmonary capillary leakage and cytokines production and NF-kappaB activation in CLP-induced sepsis in rats

BACKGROUND

Sepsis and resulting multiple system organ failure are the leading causes of mortality in intensive care units. Hydroxyethyl starch (HES) 130/0.4 was a novel preparation, developed to improve the pharmacokinetics of current medium molecular weight HES solutions. This study was designed to explore the effects of HES 130/0.4 on pulmonary capillary permeability (PCP), production of cytokines, and activation of transcription factor in septic rats induced by cecal ligation and puncture (CLP).

MATERIALS AND METHODS

Adult male Sprague Dawley rats were randomly divided into six groups (six rats/group): saline controls (30 ml/kg); CLP plus saline (30 ml/kg); CLP plus HES (7.5, 15, or 30 ml/kg, respectively), and HES alone (30 ml/kg). Mean arterial blood pressure and heart rate were monitored during the experiment process. Myeloperoxidase (MPO) activity, wet/dry weight ratio, PCP, tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, IL-10, and nuclear factor-kappa B (NF-kappaB) were investigated at 6 h.

RESULTS

We demonstrated that CLP could provoke significant injury in lung, characterized by increase in PCP, wet/dry weight ratio, MPO activity, TNF-alpha, IL-6, and IL-10 level, and NF-kappaB activation. Without obvious influence on systemic macro-hemodynamics, HES 15 ml/kg and 30 ml/kg significantly reduced CLP-induced elevation of pulmonary capillary permeability, wet/dry weight ratio, and production of IL-6. Meanwhile, HES 15 ml/kg increased IL-10 level and HES 7.5, 15, and 30 ml/kg suppressed MPO activity, TNF-alpha level, and NF-kappaB activation.

CONCLUSION

HES 130/0.4 can inhibit CLP-induced PCP by attenuating pulmonary inflammation and NF-kappaB activation in vivo.

DO PLASMA SUBSTITUTES HAVE ADDITIONAL PROPERTIES BEYOND CORRECTING VOLUME DEFICITS?

The best strategy for volume therapy has been the focus of debate and there are still no unique accepted guidelines. There is increasing evidence that some plasma substitutes possess additional effects on organ perfusion, microcirculation, tissue oxygenation, inflammation, endothelial activation, capillary leakage, and tissue edema that are beyond their volume replacing properties. Whether the different plasma substitutes differ with regard this additional effects was reviewed. The additional effects of plasma substitutes have mostly been studied experimentally or in animals, much less results are available in humans. The results are not uniform ranging from beneficial to even detrimental effects of a certain volume replacement strategy. Some important results from the literature are not reflected in the actual recommendations for treating volume deficits in the critically ill: although crystalloids have been shown to have considerable negative effects on microcirculation, organ perfusion, tissue oxygenation, and endothelial integrity, they are still often recommended as first choice volume replacement strategy. In several experimental studies hypertonic solutions have been shown to have various beneficial effects, they have not been, however, translated into humans. In future, the choice of the ideal volume replacement regimen should not only be focused on its volume restoring properties, but additional effects (e.g. on organ perfusion on, tissue oxygenation, inflammation, endothelial activation, capillary leakage) should also be taken into account when treating hypovolemia in the critically ill.

Endotoxin-induced heart dysfunction in rats: assessment of myocardial perfusion and permeability and the role of fluid resuscitation

OBJECTIVE

The pathophysiology of sepsis-induced myocardial dysfunction is still controversial. Whether microcirculatory hypoperfusion together with capillary leakage can occur in the heart wall also remains a matter of debate. The objective was to evaluate the impact of fluid resuscitation on endotoxin-induced myocardial dysfunction.

DESIGN

Adult rats were given intraperitoneal injection of endotoxin (lipopolysaccharide, Escherichia coli, 10 mg/kg) or phosphate-buffered solution, followed up by echocardiography and acetate micro-positron emission tomography scan imaging, together with final hemodynamic, biochemical, and pathologic evaluations up to 48 hrs.

SETTING

University laboratory.

SUBJECTS

Pathogen-free male Wistar rats (350 g).

INTERVENTIONS

Influence of isovolumic fluid infusion type (saline vs. pentastarch) on these variables was assessed in 11 groups of six animals including an unchallenged control one.

MEASUREMENTS AND MAIN RESULTS

Endotoxin injection induced a) myocardial dysfunction (decrease of approximately 15-20% in left ventricular ejection fraction); b) ventricular enlargement (approximately 1.5- to 1.7-fold increase in left ventricular systolic volume); c) cardiac output increase (10-15%); d) myocardial hypoperfusion ( approximately 1.5- to 2-fold decrease in acetate k1 constant rate); e) increased oxygen consumption (k2); and f) interstitial wall increase. Endotoxin injection also enhanced levels of arterial lactates and troponin I. Colloid (pentastarch) over crystalloid (saline) fluid resuscitation significantly reversed echocardiographic changes, some positron emission tomography imaging alterations, and lactate and troponin I levels without further enhancing interstitial spaces.

CONCLUSION

Endotoxin can induce reversible myocardial alterations with evidence of coronary hypoperfusion and heart wall enlargement/damage, some of which can be prevented by fluid resuscitation. The use of crystalloids is less beneficial than pentastarch.

EFFECT OF DIFFERENT RESUSCITATION FLUIDS ON CYTOKINE RESPONSE IN A RAT MODEL OF HEMORRHAGIC SHOCK

This study was designed to determine the effects of different resuscitation fluids on the production of proinflammatory and anti-inflammatory cytokines in an animal model of hemorrhagic shock. Wistar male rats (n = 24; 8/group) were subjected to a volume-controlled hemorrhagic shock for 30 minutes and resuscitated as follows: (1) sham group without resuscitation, (2) lactated Ringer solution (LR), 3:1; (3) 4% hydroxyethyl starch (HES) solution, 1:1; and (4) 4% modified fluid gelatin (GEL), 1:1. Hemodynamic parameters were recorded, and blood samples were collected at 0 min and 30, 90, 150, 210, 270, and 330 min after hemorrhage for plasma levels of IL-6, IL-10, and TNFalpha. The circulating concentrations of IL-6 at 90, 150, 210, 270, and 330 min and TNFalpha levels at 150, 210, and 270 min after hemorrhage were significantly elevated in animals resuscitated with GEL compared with HES or LR (P < 0.05). At 210, 270, and 330 min, IL-10 concentration was decreased significantly in GEL-resuscitated rats compared with rats resuscitated with LR or HES (P < 0.05). Mean blood pressure and serum levels of lactate after resuscitation were not different among three kinds of fluids. LR, HES, and GEL are comparable in volume efficacy for resuscitation of hemorrhagic shock but are associated with different postresuscitation immune responses. Resuscitation with GEL may be associated with cytokine production favoring a proinflammatory response. The marked elevation of IL-6 observed in the GEL-treated animals may play a role in the relatively high frequency of anaphylactoid reaction in clinical use of GEL.