Efficacy of hetastarch in the resuscitation of patients with multisystem trauma and shock

A Critical Reassessment of the Kidney Risk Caused by Tetrastarch Products in the Perioperative and Intensive Care Environments

Purpose: To reassess the results of former meta-analyses focusing on the relationship between novel HES preparations (130/0.4 and 130/0.42) and acute kidney injury. Previous meta-analyses are based on studies referring to partially or fully unpublished data or data from abstracts only. Methods: The studies included in the former meta-analyses were scrutinized by the authors independently. We completed a critical analysis of the literature, including the strengths, weaknesses and modifiers of the studies when assessing products, formulations and outcomes. Results: Both the published large studies and meta-analyses show significant bias in the context of the deleterious effect of 6% 130/0.4-0.42 HES. Without (1) detailed hemodynamic data, (2) the exclusion of other nephrotoxic events and (3) a properly performed evaluation of the dose-effect relationship, the AKI-inducing property of 6% HES 130/0.4 or 0.42 should not be considered as evidence. The administration of HES is safe and effective if the recommended dose is respected. Conclusions: Our review suggests that there is questionable evidence for the deteriorating renal effect of these products. Further well-designed, randomized and controlled trials are needed. Additionally, conclusions formulated for resource-rich environments should not be extended to more resource-scarce environments without proper qualifiers provided.

Fluid Resuscitation in Tactical Combat Casualty Care: Yesterday and Today

The prevailing wisdom for the prehospital fluid resuscitation of trauma victims in hemorrhagic shock in 1992 was to administer 2 L of crystalloid solution as rapidly as possible. A review of the fluid resuscitation literature found that this recommendation was not well supported by the evidence at the time. Prehospital fluid resuscitation strategies were reevaluated in the 1993-1996 Tactical Combat Casualty Care (TCCC) research program. This article reviews the advances in prehospital fluid resuscitation as recommended by the original TCCC Guidelines and modified over the following 2 decades. These advances include hypotensive resuscitation, use of prehospital whole blood or blood components when feasible, and use of Hextend or selected crystalloids when logistical considerations make blood or blood component use not feasible.

Transfusion practices in trauma

Resuscitation of a severely traumatised patient with the administration of crystalloids, or colloids along with blood products is a common transfusion practice in trauma patients. The determination of this review article is to update on current transfusion practices in trauma. A search of PubMed, Google Scholar, and bibliographies of published studies were conducted using a combination of key-words. Recent articles addressing the transfusion practises in trauma from 2000 to 2014 were identified and reviewed. Trauma induced consumption and dilution of clotting factors, acidosis and hypothermia in a severely injured patient commonly causes trauma-induced coagulopathy. Early infusion of blood products and early control of bleeding decreases trauma-induced coagulopathy. Hypothermia and dilutional coagulopathy are associated with infusion of large volumes of crystalloids. Hence, the predominant focus is on damage control resuscitation, which is a combination of permissive hypotension, haemorrhage control and haemostatic resuscitation. Massive transfusion protocols improve survival in severely injured patients. Early recognition that the patient will need massive blood transfusion will limit the use of crystalloids. Initially during resuscitation, fresh frozen plasma, packed red blood cells (PRBCs) and platelets should be transfused in the ratio of 1:1:1 in severely injured patients. Fresh whole blood can be an alternative in patients who need a transfusion of 1:1:1 thawed plasma, PRBCs and platelets. Close monitoring of bleeding and point of care coagulation tests are employed, to allow goal-directed plasma, PRBCs and platelets transfusions, in order to decrease the risk of transfusion-related acute lung injury.

Hydroxyethyl starch (HES) versus other fluid therapies: effects on kidney function

BACKGROUND

Hydroxyethyl starches (HES) are synthetic colloids commonly used for fluid resuscitation to replace intravascular volume, yet they have been increasingly associated with adverse effects on kidney function. This is an update of a Cochrane review first published in 2010.

OBJECTIVES

To examine the effects of HES on kidney function compared to other fluid resuscitation therapies in different patient populations.

SEARCH METHODS

We searched the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library), MEDLINE, EMBASE, MetaRegister and reference lists of articles. The most recent search was completed on November 19, 2012.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs in which HES was compared to an alternate fluid therapy for the prevention or treatment of effective intravascular volume depletion. Primary outcomes were renal replacement therapy (RRT), author-defined kidney failure and acute kidney injury (AKI) as defined by the RIFLE criteria.

DATA COLLECTION AND ANALYSIS

Screening, selection, data extraction and quality assessments for each retrieved article were carried out by two authors using standardised forms. All outcomes were analysed using relative risk (RR) and 95% confidence intervals (95% CI). Authors were contacted when published data were incomplete. Preplanned sensitivity and subgroup analyses were performed after data were analysed with a random-effects model.

MAIN RESULTS

This review included 42 studies (11,399 patients) including 19 studies from the original review (2010), as well as 23 new studies. Fifteen studies were excluded from the original review (nine retracted from publication due to concerns about integrity of data and six lacking individual patient creatinine data for the calculation of RIFLE criteria). Overall, there was a significant increase in the need for RRT in the HES treated individuals compared to individuals treated with other fluid therapies (RR 1.31, 95% CI 1.16 to 1.49; 19 studies, 9857 patients) and the number with author-defined kidney failure (RR 1.59, 95% CI 1.26 to 2.00; 15 studies, 1361 patients). The RR of AKI based on RIFLE-F (failure) criteria also showed an increased risk of AKI in individuals treated with HES products (RR 1.14, 95% CI 1.01 to 1.30; 15 studies, 8402 participants). The risk of meeting urine output and creatinine based RIFLE-R (risk) criteria for AKI was in contrast in favour of HES therapies (RR 0.95, 95% CI 0.91 to 0.99; 20 studies, 8769 patients). However, when RIFLE-R urine output based outcomes were excluded as per study protocol, the direction of AKI risk again favoured the other fluid type, with a non-significant RR of AKI in HES treated patients (RR 1.05, 95% CI 0.97 to 1.14; 8445 patients). A more robust effect was seen for the RIFLE-I (injury) outcome, with a RR of AKI of 1.22 (95% CI 1.08 to 1.37; 8338 patients). No differences between subgroups for the RRT and RIFLE-F based outcomes were seen between sepsis versus non-sepsis patients, high molecular weight (MW) and degree of substitution (DS) versus low MW and DS (≥ 200 kDa and > 0.4 DS versus 130 kDa and 0.4 DS) HES solutions, or high versus low dose treatments (i.e. ≥ 2 L versus < 2 L). There were differences identified between sepsis versus non-sepsis subgroups for the RIFLE-R and RIFLE-I based outcomes only, which may reflect the differing renal response to fluid resuscitation in pre-renal versus sepsis-associated AKI. Overall, methodological quality of the studies was good.

AUTHORS' CONCLUSIONS

The current evidence suggests that all HES products increase the risk in AKI and RRT in all patient populations and a safe volume of any HES solution has yet to be determined. In most clinical situations it is likely that these risks outweigh any benefits, and alternate volume replacement therapies should be used in place of HES products.

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.

Fluid resuscitation in multiple trauma patients

PURPOSE OF REVIEW

Fluid resuscitation in trauma patients with hemorrhagic shock is controversially discussed in the literature. The coincidence of brain injury complicates management of these patients. This article summarizes the current knowledge on nonblood component fluid resuscitation and choice of fluids in patients with multiple trauma.

RECENT FINDINGS

Whereas current evidence suggests the efficacy of fluid therapy in hemorrhagic shock without active bleeding, experimental and clinical data demonstrate that aggressive volume challenge may be futile or even deleterious in the setting of uncontrolled hemorrhage. Large amounts of isotonic crystalloids may be associated with hypothermia, acidosis and inflammation. In patients with traumatic brain injury hypertonic solutions may positively influence inflammation and intracranial pressure without affecting neurologic outcome or mortality.

SUMMARY

To date no large-scale clinical studies exist to either support or refute the use of nonblood component fluid resuscitation of hemorrhagic shock in trauma patients. The optimal choice of fluid remains to be determined, but existing evidence suggests avoiding crystalloids in favor of hypertonic solutions. The role of modern, iso-oncotic colloids in the treatment of hemorrhagic shock has not yet been sufficiently defined. In patients with concomitant brain injury, arterial hypotension must be avoided and infusion of hypotonic solutions is obsolete, whereas administration of hypertonic solutions may exert beneficial effects beyond hemodynamic stabilization.

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 acute management of trauma hemorrhage: a systematic review of randomized controlled trials

Introduction

Worldwide, trauma is a leading cause of death and disability. Haemorrhage is responsible for up to 40% of trauma deaths. Recent strategies to improve mortality rates have focused on optimal methods of early hemorrhage control and correction of coagulopathy. We undertook a systematic review of randomized controlled trials (RCT) which evaluated trauma patients with hemorrhagic shock within the first 24 hours of injury and appraised how the interventions affected three outcomes: bleeding and/or transfusion requirements; correction of trauma induced coagulopathy and mortality.

Methods

Comprehensive searches were performed of MEDLINE, EMBASE, CENTRAL (The Cochrane Library Issue 7, 2010), Current Controlled Trials, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP) and the National Health Service Blood and Transplant Systematic Review Initiative (NHSBT SRI) RCT Handsearch Database.

Results

A total of 35 RCTs were identified which evaluated a wide range of clinical interventions in trauma hemorrhage. Many of the included studies were of low methodological quality and participant numbers were small. Bleeding outcomes were reported in 32 studies; 7 reported significantly reduced transfusion use following a variety of clinical interventions, but this was not accompanied by improved survival. Minimal information was found on traumatic coagulopathy across the identified RCTs. Overall survival was improved in only three RCTs: two small studies and a large study evaluating the use of tranexamic acid.

Conclusions

Despite 35 RCTs there has been little improvement in outcomes over the last few decades. No clear correlation has been demonstrated between transfusion requirements and mortality. The global trauma community should consider a coordinated and strategic approach to conduct well designed studies with pragmatic endpoints.

Hydroxyethyl starch (HES) versus other fluid therapies: effects on kidney function

BACKGROUND

Hydroxyethyl starches (HES) are synthetic colloids commonly used for fluid resuscitation, yet controversy exists about their impact on kidney function.

OBJECTIVES

To examine the effects of HES on kidney function compared to other fluid resuscitation therapies in different patient populations.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL, in The Cochrane Library), MEDLINE, EMBASE, MetaRegister and reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs in which HES was compared to an alternate fluid therapy for the prevention or treatment of effective intravascular volume depletion. Primary outcomes were renal replacement therapy (RRT), author-defined kidney failure and acute kidney injury (AKI) as defined by the RIFLE criteria. Secondary outcomes included serum creatinine and creatinine clearance.

DATA COLLECTION AND ANALYSIS

Screening, selection, data extraction and quality assessments for each retrieved article were carried out by two authors using standardised forms. Authors were contacted when published data were incomplete. Preplanned sensitivity and subgroup analyses were performed after data were analysed with a random effects model.

MAIN RESULTS

The review included 34 studies (2607 patients). Overall, the RR of author-defined kidney failure was 1.50 (95% CI 1.20 to 1.87; n = 1199) and 1.38 for requiring RRT (95% CI 0.89 to 2.16; n = 1236) in HES treated individuals compared with other fluid therapies. Subgroup analyses suggested increased risk in septic patients compared to non-septic (surgical/trauma) patients. Non-septic patient studies were smaller and had lower event rates, so subgroup differences may have been due to lack of statistical power in these studies. Only limited data was obtained for analysis of kidney outcomes by the RIFLE criteria. Overall, methodological quality of studies was good but subjective outcomes were potentially biased because most studies were unblinded.

AUTHORS' CONCLUSIONS

Potential for increased risk of AKI should be considered when weighing the risks and benefits of HES for volume resuscitation, particularly in septic patients. Large studies with adequate follow-up are required to evaluate the renal safety of HES products in non-septic patient populations. RIFLE criteria should be applied to evaluate kidney function in future studies of HES and, where data is available, to re-analyse those studies already published. There is inadequate clinical data to address the claim that safety differences exist between different HES products.

The use of hypertonic saline for fluid resuscitation in sepsis: a review

Early volume resuscitation of a patient with sepsis has been shown to reduce morbidity, mortality, and healthcare resource consumption. Hypertonic saline offers a theoretically viable option for volume resuscitation. This article reviews the current information available regarding fluid resuscitation in patients with sepsis, with emphasis on the use of hypertonic saline.

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.

Practice parameters for hemodynamic support of sepsis in adult patients: 2004 update

OBJECTIVE

To provide the American College of Critical Care Medicine with updated guidelines for hemodynamic support of adult patients with sepsis.

DATA SOURCE

Publications relevant to hemodynamic support of septic patients were obtained from the medical literature, supplemented by the expertise and experience of members of an international task force convened from the membership of the Society of Critical Care Medicine.

STUDY SELECTION

Both human studies and relevant animal studies were considered.

DATA SYNTHESIS

The experts articles reviewed the literature and classified the strength of evidence of human studies according to study design and scientific value. Recommendations were drafted and graded levels based on an evidence-based rating system described in the text. The recommendations were debated, and the task force chairman modified the document until <10% of the experts disagreed with the recommendations.

CONCLUSIONS

An organized approach to the hemodynamic support of sepsis was formulated. The fundamental principle is that clinicians using hemodynamic therapies should define specific goals and end points, titrate therapies to those end points, and evaluate the results of their interventions on an ongoing basis by monitoring a combination of variables of global and regional perfusion. Using this approach, specific recommendations for fluid resuscitation, vasopressor therapy, and inotropic therapy of septic in adult patients were promulgated.

Fluid resuscitation in the Canadian Forces

In general, the Canadian Forces follow widely accepted principles of fluid resuscitation. These are simply guidelines for fluid resuscitation, and the Canadian Forces currently do not have an absolute doctrine that the clinician in the field must follow. In addition, these principles are adapted to our field environment and the tactical situation that may present itself. In general, Advanced Trauma Life Support guidelines are followed not only for fluid resuscitation but also for the overall resuscitation of the patient. Ringer's lactate is the primary resuscitation fluid that is used. Emphasis is placed on attempting to control ongoing hemorrhage specifically either with direct pressure, surgical control, or splinting of long bone or pelvic fractures at the earliest possible stage.

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, the Cochrane Controlled Trials Register (2002 Issue 3), MEDLINE (1994-2002/07), EMBASE (1974-2002 August week 1), and the National Research Register (2002 issue 3). Bibliographies of trials retrieved were searched, and drug companies manufacturing colloids were contacted for information. The search was last updated in September 2002.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing colloid solutions in critically ill and surgical patients thought to need volume replacement. The main 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

Fifty-seven trials met the inclusion criteria, with a total of 3659 participants. Quality of allocation concealment was judged to be adequate in 20 trials and poor or uncertain in 37. Deaths were obtained from 36 trials. For albumin or PPF versus hydroxyethyl starch (HES) 20 trials (n=1029) reported mortality. The pooled relative risk (RR) was 1.17 (95% CI 0.91, 1.50). For albumin or PPF versus gelatin four trials (n=542) reported mortality. The RR was 0.99 (0.69, 1.42). For gelatin vs HES 11 trials (n=945) reported mortality, RR was 1.00 (0.78,1.28). RR was not estimable in the albumin vs dextran, gelatin vs dextran, and HES vs dextran groups. Thirty-six trials recorded the amount of blood transfused, however quantitative analysis was not possible due to skewness and variable reporting. Fifteen trials recorded adverse reactions, but none occurred.

REVIEWER'S 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.

Fluid Therapy in the Critically Ill Patient

The administration of intravenous fluids in the critically ill patient presents many challenges for clinicians. Intravenous fluids are usually categorized as either crystalloids or colloids, with each having distinct advantages and disadvantages in various patient populations. The appropriate selection of fluid type remains an issue of great debate in the critical care literature and has been the subject of numerous comparative studies. Despite the vast amount of data available, there is no clear consensus in the literature to direct the clinician in the choice of fluid type. This article will provide an overview of fluid distribution within the body and the factors that affect this distribution, a review of the various types of fluids administered in the critically ill patient, and the rationale for the selection of each type. A review of the literature surrounding the colloid-crystalloid controversy is provided.

A randomized, blinded trial comparing the hemostatic effects of pentastarch versus hetastarch

BACKGROUND

HES solutions provide a sterile, alternative colloidal fluid to albumin solutions and/or plasma in the management of patients who need plasma volume expansion. Solutions of HES are widely accepted internationally but are used only modestly in the United States, largely because of concerns over hemostasis.

STUDY DESIGN AND METHODS

A randomized, blinded, two-arm trial comparing the hemostatic effects of pentastarch versus hetastarch when infused in the clinically relevant dose of 90 g of HES dissolved in 1.5 L of saline was conducted. Multiple studies of fibrin clot formation, fibrinogen/fibrinolysis, and platelet (PLT) functions were performed before and on multiple occasions for 70 days following HES infusion.

RESULTS

Several significant abnormalities of hemostasis assay results occurred following HES infusions, with hetastarch causing significantly greater abnormalities than pentastarch. Individual clotting proteins and blood PLTs fell modestly because of plasma volume expansion and hemodilution. A fall in excess of that caused by hemodilution was demonstrated for von Willebrand factor antigen plus its associated FVIII and ristocetin cofactor activities. The partial thromboplastin time was prolonged, whereas the thrombin time was shortened. Plt function abnormalities were seen in most subjects to a modest degree. Studies of fibrinolysis were normal.

CONCLUSIONS

Solutions of hetastarch produce significant abnormalities of some hemostasis laboratory results when infused at clinically relevant doses, but it is unlikely that the modest hemostatic abnormalities produced at these doses per se would lead to clinical bleeding. Hetastarch causes greater hemostatic abnormalities than pentastarch, and because both HES solutions have comparable plasma volume-expanding effects, it is reasonable to prefer pentastarch as a plasma volume expander.

Intravenous albumin versus hydroxyethyl starch for the prevention of ovarian hyperstimulation in an in-vitro fertilization programme: a prospective randomized placebo controlled study

A prospective randomized placebo controlled clinical trial was carried out on 250 patients (cycles) considered at risk of developing OHSS in an IVF programme. Criteria for inclusion were: estradiol value of more than 3000 pg/ml or the presence of more than 20 follicles on the day of hCG administration. Patients were randomized by using a random table to receive either 20% human albumin 50 ml (n: 82); 6% hydroxyethyl starch (200/0.5) 500 ml (n: 85) or a placebo of 500 ml 0.9% NaCl solution (n: 83) over 30 min during oocyte collection. Groups were similar with respect to patients' age, estradiol levels on hCG day, body mass index, number of oocytes retrieved, number of embryos transferred and pregnancies (P>0.05). There was no severe OHSS in patients who received albumin and HES while four patients who received placebo developed severe OHSS. On the other hand moderate OHSS was encountered in four patients in the albumin group; five patients receiving HES; and 12 patients receiving placebo. There was a statistically significant difference in the incidence of moderate, severe and overall OHSS among groups (P values of <0.05, <0.05, and <0.01, respectively). Both HES and albumin significantly reduced the incidence of moderate, severe and overall incidence of OHSS. It is concluded that hydroxyethyl starch is a cheaper and safer alternative to Human Albumin in OHSS prevention.

Effect of hydroxyethyl starch on coagulopathy in a swine model of hemorrhagic shock resuscitation

BACKGROUND

Hydroxyethyl starch (HES) has a known dose-dependant effect on coagulopathy. The purpose of this study was to determine the effect of HES on coagulopathy after a period of hemorrhagic shock.

METHODS

Anesthetized swine underwent a 15-minute, 40% blood volume hemorrhage (28 mL/kg) and a 1-hour shock period, followed by resuscitation with sham resuscitation (group I); 6% HES, 15 mL/kg (group II); 5% albumin, 15 mL/kg (group III); lactated Ringer's solution, 39 mL/kg, and 6% HES, 15 mL/kg (group IV); and lactated Ringer's solution, 39 mL/kg, and 5% albumin, 15 mL/kg (group V). Coagulation function was measured by bleeding time, prothrombin time, partial thromboplastin time, fibrinogen, platelet count, and thromboelastography.

RESULTS

Platelet counts decreased significantly (p < 0.05) in all resuscitation groups except the sham resuscitation group. A significant decrease in platelets, fibrinogen levels, and maximum amplitude on thromboelastography was related to a dilutional effect of the fluid given and not a result of HES at the dose tested.

CONCLUSION

The linear dose-related coagulopathic effects of HES when given at moderate doses does not seem to be worsened by prolonged periods of hemorrhagic shock. The coagulopathy seen during resuscitation from hemorrhagic shock seems to be a dilutional effect.

Use of intraoperative hetastarch priming during coronary bypass

BACKGROUND

The use of hetastarch during coronary bypass surgery has been limited due to its unresolved potential risk for hemorrhage. Therefore, the purpose of this study was to investigate the effects of using 6% hetastarch in priming cardiopulmonary bypass (CPB) circuitry on the need for blood product transfusions and outcome after coronary bypass.

MATERIALS AND METHODS

This nonrandomized retrospective study involved 887 patients who underwent isolated primary coronary artery bypass grafting. Based on the type of solution used in priming the CPB circuitry, patients were stratified into the following four different groups: group 1, crystalloid (500 mL; n = 211); group 2, 25% human albumin (50 mL; n = 217); group 3, 6% hetastarch (500 mL; n = 298); and group 4, 25% human albumin (50 mL) and 6% hetastarch (500 mL; n = 161). Patient characteristics and clinical variables were compared among the groups using the Kruskal-Wallis test. Patient survival estimates were compared using log-rank test.

RESULTS

Demographic patient characteristics for all groups were similar (p > 0.05). Intraoperative and perioperative variables among groups were comparable (p > 0.05). The use of hetastarch as a part of prime solution in CPB circuitry did not alter the need for banked blood, platelets, or fresh frozen plasma transfusions (p > 0.05). The length of stay in the ICU or in the hospital was unaffected in all groups. The early (ie, 30-day) mortality rate was 1.4% in group 1, 1.8% in group 2, 1.0% in group 3, and 3.1% in group 4. Long-term survival among the groups was unaffected by the type of priming solution.

CONCLUSIONS

The use of hetastarch in priming CPB circuitry is devoid of any added hemorrhagic risk after coronary bypass, and the type of prime solution for CPB has no influence on the early or late survival rates of patients undergoing primary coronary bypass.

Coagulation effects of a recently developed hydroxyethyl starch (HES 130/0.4) compared to hydroxyethyl starches with higher molecular weight

BACKGROUND

Hydroxyethyl starches (HES) are known to interfere with blood coagulation according to molecular weight, the degree of substitution and the C2/C6 ratio. A recently developed low molecular hydroxyethyl starch (HES 130/0.4) was designed to reduce the blood compromising potency.

METHODS

In this study, effects of a 30% in vitro haemodilution with the new HES preparation (HES 130/0.4) in comparison to HES 200/0.5, HES 450/0.7 and sodium chloride solution were investigated using intrinsic and extrinsic activated thrombelastography (TEG) and plasmatic coagulation tests.

RESULTS

Whereas plasmatic tests revealed no prolongation of coagulation by HES in comparison to sodium chloride, the TEG variables clotting time, clot formation time and maximal clot firmness showed a significant (P<0.05) inhibition by all the HES preparations. The inhibition was most pronounced in HES 450 (P<0.05 vs HES 130) while HES 130 did not show a statistically significant difference in extrinsic activated maximal clot firmness when compared to sodium chloride.

CONCLUSION

These in vitro results demonstrate that hydroxythyl starches especially compromise clot polymerisation. The new preparation HES 130/0.4 seems to inhibit platelet function to a lesser extent than hydroxyethyl starch preparations with a higher molecular weight and degree of substitution.

Lung lymph response to overinfusion with hydroxyethyl starch in sheep. Comparative studies of high and low molecular weight compounds

BACKGROUND

Several hydroxyethyl starch (HES) solutions are available clinically. We performed comparative studies of low and high molecular weight HES to evaluate the effects on lung lymph flow in sheep, to see the difference in the types of HES.

METHODS

We prepared awake sheep with vascular monitorings and lung lymph fistulas. We measured systemic artery pressure (Psa), pulmonary artery pressure (Ppa), and left atrial pressure (Pla) continuously. Cardiac output (CO) was measured every 30 min. Lung lymph flow (Qlym) was collected every 15 min. After baseline measurements, two HES solutions were infused over 2 h, respectively. Experiment 1 (n=6): low molecular weight HES (MW 70 000, substitution ratio 0.5-0.55), Experiment 2 (n=5): high molecular weight HES (MW 450 000, substitution ratio 0.7).

RESULTS

Both low and high molecular HES behaved similarly as a volume expander, increasing Psa, CO, Pla and Ppa, and decreasing hematocrit. In addition, the actual oncotic pressure gradient (plasma - lymph) was widened after the start of either low or high molecular HES, but the value for high molecular HES was significantly higher than that for low molecular HES. Qlym of low molecular HES rose significantly from the baseline and the percent increase in Qlym for low molecular HES was significantly higher than that for high molecular HES.

CONCLUSION

These data suggest that low molecular HES is as useful a plasma substitute as high molecular HES, but may increase lung fluid filtration in the overinfused state.

Platelet aggregation during abdominal surgery in an experimental pig model: the effects of presurgical antibiotic protocols and volume replacement with hydroxyethyl starch

The effect of presurgical antibiotic protocols in combination with hemodilution on platelet aggregation was studied. Thirty pigs were randomly assigned to three groups. Group 1 received amoxicillin/clavulanic acid, group 2 metronidazole+cefuroxime, and group 3, as a control, sodium chloride. They underwent laparotomy, massive blood loss, and volume replacement with hydroxyethyl starch 200, followed by an anaphylactoid reaction. Platelet aggregation was measured by the turbidometric method. Neither antibiotic protocols had any effect on platelet aggregation as compared with the control group. In all three groups, aggregation to ADP and collagen was significantly reduced after volume replacement with hydroxyethyl starch. In contrast, the sensitivity to the aggregating effects of collagen was increased as assessed by a higher frequency of responses to low concentrations of collagen and a shortened latency of the aggregation response after collagen addition. Further in vitro studies revealed that dilution of plasma with hydroxyethyl starch specifically induced the changes seen after in vivo volume replacement. The results suggest that the plasma substitute hydroxyethyl starch 200 increases the sensitivity to low doses of collagen, an effect never described before and considered of clinical relevance.

Hydroxyethyl starch reduces the chemotaxis of white cells through endothelial cell monolayers

BACKGROUND

Polymorphonuclear leukocytes (PMNs) play a tremendous role during inflammatory processes. PMNs have to pass a monolayer of endothelial cells to migrate into the extravascular space. Hydroxyethyl starch (HES) is frequently used as a volume expander in critically ill patients.

STUDY DESIGN AND METHODS

The aim of this study was to investigate whether HES influences the chemotaxis of PMNs through endothelial cell monolayers by using a test system that allows the simultaneous treatment of both cell types. Human umbilical endothelial cells were cultured on microporous membrane filters. PMNs were isolated and PMN chemotaxis was studied.

RESULTS

The number of untreated PMNs that migrated through untreated endothelial cell monolayers in response to a chemoattractant was used as a control and set as 100 percent. In clinically relevant concentrations, HES was able to significantly decrease PMN chemotaxis through endothelial cell monolayers, showing a dose-dependent effect (0.1 mg/mL: 99.6 +/- 10.9%, p = NS compared to control; 1 mg/mL: 82.4 +/- 8.3%, p<0.05 compared to control; 10 mg/mL: 62.9 +/- 11.7%, p<0.05). In this assay, both cell types (PMNs and endothelial cells in the monolayer) were treated simultaneously, which simulated the clinical situation after an intravenous injection of HES. The treatment of one cell type, PMNs (89.6 +/- 8.8%, p<0.05) or endothelial cells in the monolayer (76.2 +/- 9.4%, p<0.05), suggests that the influence on endothelial cells is greater.

CONCLUSION

HES is able to significantly reduce the chemotaxis of PMNs through endothelial cell monolayers. The possible clinical consequence of a moderate reduction in endothelium-mediated PMN chemotaxis in critically ill patients remains to be evaluated.

Peri-operative tolerance to large-dose 6% HES 200/0.5 in major urological procedures compared with 5% human albumin

We studied the long-term efficacy and safety of medium-molecular-weight hydroxyethyl starch (HES) administered in doses above 20 ml.kg-1 during major blood replacement therapy. Blood replacement for 50 patients used 6% HES 200/0.5 (HES group) or 5% albumin (ALB group) and additional blood components according to a defined protocol. We compared safety, efficacy and costs in 4 peri-operative days. Colloid administration on the day of surgery was 38.4 ml.kg-1 (HES group) and 35.1 ml.kg-1 (ALB group). Haemodynamic, coagulation and renal function parameters were similar. Although total serum protein was still different on the third postoperative day (53.45 gl-1 (HES group) and 60.6 gl-1 (ALB group) (p < 0.01)) the colloid osmotic pressure always remained above 19.5 (2.5) mmHg (HES group). Blood loss (3810 (1632) ml (HES group) and 3455 (1733) ml (ALB group)) and the requirement for blood components was comparable. Costs were reduced by 35% (p < 0.05) in the HES group. We conclude that using 6% HES 200/0.5 as the only colloid for treatment even of large blood loss is a safe and economic alternative to albumin.

Replacement of massive blood loss

Treatment of massive blood loss has experienced major changes during the recent decade. The transition towards pure component therapy has been the most significant issue, which has compelled the clinician to revise some of their basic strategies in treatment of massively bleeding patients. The importance of adequate volume resuscitation with crystalloids and colloids is still unrefutable, but the therapy of hemorrhagic derangements has changed. Plasma-poor red cells (RC) are now commonly used instead of whole blood (WB) or packed red blood cells (PRBC) to correct oxygen carrying capacity during massive blood loss. As the plasma content of RC is minimal, deficit of plasma and coagulation factors develops earlier than during transfusion of WB and PRBC. Hypofibrinogenemia develops first followed by other coagulation factor deficits and later by thrombocytopenia. Therefore the use of fresh frozen plasma (FFP) is the primary intervention to treat abnormal bleeding encountered in the replacement of massive blood loss with RC. As the development of thrombocytopenia is a highly individual phenomenon, the transfusion of platelets should be guided by repeatedly determined platelet counts.

Fluid therapy. Crystalloids and colloids

Appropriate fluid therapy requires an understanding of fluid dynamics and pathologic alterations during various disease states. In addition, it requires an understanding of the pharmacologic differences of available fluids. Crystalloid fluids and colloid fluids can be used in combination to treat a variety of volume-deficient states. Synthetic colloids are also used to treat hyponcotic states. Blood products are used to replace blood components and coagulation proteins. Frequent monitoring and reassessment are required to prevent volume overload and life-threatening edema.

Large-dose administration of 6% hydroxyethyl starch 200/0.5 total hip arthroplasty: plasma homeostasis, hemostasis, and renal function compared to use of 5% human albumin

Within a daily dose of 20 mL/kg, medium-molecular hydroxyethyl starch (HES) is a safe and effective colloid for intravascular blood volume replacement. The effect of large doses on coagulation and renal function is unknown. We prospectively studied 41 patients undergoing total hip arthroplasty during the perioperative period. Inevitable blood loss was replaced with HES (HES group) or albumin (ALB group) in combination with packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelets. Hemodynamic, oncotic, coagulation, and renal functions were compared initially, at the end of surgery, during the postoperative period (1, 3, and 6 h), and also with respect to the volume of colloid solution administered (1500, 2000, and 3000 mL). Total intake and output balances, as well as the costs of blood replacement therapy, were registered at the end of the study. We found differences in oncotic variables even at 6 h after surgery (total serum proteins [TSP]:HES 36.4 +/- 7.9 g/L versus ALB 55.6 +/- 6.1 g/L, P < 0.01; serum albumin:HES 25.5 +/- 5.3 g/L versus ALB 42.0 +/- 5.6 g/L, P < 0.01). Colloid osmotic pressure (COP) and hemodynamic, coagulation, and renal functions were comparable, as was total blood loss (HES 4247 +/- 2090 mL versus ALB 4051 +/- 2830 mL). Total requirements for colloid solutions (HES 35.9 +/- 7.4 mL/kg versus ALB 33.9 +/- 10.5 mL/kg), PRBC, FFP, or platelets were comparable, whereas total cost of blood replacement therapy was 33% less in the HES group. With respect to efficacy and side effects on coagulation and renal function, medium molecular HES is an appropriate and economic alternative to albumin at daily doses of up to at least 36 mL/kg.

Comparison of hetastarch with albumin for postoperative volume expansion in children after cardiopulmonary bypass

OBJECTIVE

Hetastarch has been studied as a volume expander in adults after cardiopulmonary bypass (CPB) and in recommended dosages has not altered coagulation studies or increased clinical bleeding. Hetastarch was compared with albumin in children after CPB to determine whether hetastarch use was associated with increased clinical bleeding or alteration of coagulation studies.

DESIGN

Randomized double-blinded study.

SETTING

University-affiliated children's hospital.

PARTICIPANTS

Forty-seven children age 1 year or greater (mean 72.8 months; range 12 months to 15.5 years) scheduled for repair of congenital heart disease with moderate hypothermia were randomized to receive hetastarch or albumin as a postoperative volume expander during the first 24 hours after surgery.

INTERVENTIONS

Thirty-eight children required colloid replacement therapy. Blood pressure, central venous pressure, urine output, and chest tube drainage were used to determine colloid requirement.

MEASUREMENTS AND MAIN RESULTS

Clinical bleeding and laboratory studies of coagulation were evaluated as were requirements for colloid, crystalloid, and blood products. Twenty children received 6% hetastarch, and 18 received 5% albumin. No differences were found in the amount of replacement fluids required, or in coagulation parameters in children receiving 20 mL/kg or less of either colloid replacement therapy. An increase in prothrombin time was demonstrated in children who received greater than 20 mL/kg of 6% hetastarch (p = 0.006); however, no difference in clinical bleeding or blood product requirement was demonstrated between the hetastarch or albumin groups receiving more than 20 mL/kg.

CONCLUSION

This study demonstrated that 6% hetastarch is safe and an effective plasma volume expander in the postoperative management of children, using volumes up to 20 mL/kg. Close laboratory monitoring and careful evaluation of clinical bleeding are suggested when larger doses of hetastarch are administered because of prolongation of the prothrombin time with more than 20 mL/kg of hetastarch.

[Indications and role of albumin for vascular loading in the operating room]

Prospective clinical studies on albumin and non human colloids, administered peroperatively, were analysed. Only those with a level of evidence I or II were considered. On the basis of the cost-effectiveness ratio, albumin should not be the first choice treatment for peroperative plasma volume expansion. Low molecular weight hydroxyethylstarch is as efficient for restoration and maintenance of volaemia and colloid osmotic pressure. Albumin is administered when other colloids are contra-indicated or when their upper limit of volume has been reached.

Hydroxyethyl starch versus lactated Ringer's solution in the chronic maternal-fetal sheep preparation: a pharmacodynamic and pharmacokinetic study

Administration of fluids intravenously prior to spinal and epidural analgesia in obstetrics is required to prevent maternal hypotension and fetal hypoxia. A colloid solution, such as hydroxyethyl starch (HES), might be preferable considering the capacity to stay intravascularly for a longer period. In this study the placental transfer of HES and the hemodynamic effects after infusion were investigated using a chronic maternal-fetal sheep preparation. Either 500 mL HES 10% or 750 mL lactated Ringer's solution (RL) was infused intravenously into the ewe over 30 min. Fetal and maternal blood were assayed for HES, blood gases, and acid-base status before and at regular intervals after infusion. Maternal and fetal cardiovascular variables were recorded continuously for 90 min. After HES infusion, maternal HES levels peaked at 30 min ranging from 6.9 mg/mL to 12.1 mg/mL and declined at 24 h to levels between 0.3 mg/mL and 2.8 mg/mL. Mean fetal HES concentrations remained below 0.3 mg/mL. Infusion of HES decreased hemoglobin (Hb) and plasma viscosity (PV) in the mother. Infusion of RL decreased Hb, but did not change PV. Infusion of HES significantly increased uterine blood flow (UBF), cardiac output (CO), total oxygen-delivery capacity, and uterine artery oxygen delivery. In contrast, infusion of RL did not significantly change these variables. Infusion of HES increases UBF, CO, and uterine and total oxygen-carrying capacity in the pregnant ewe. No significant transplacental transfer of HES was shown.

Effects of hydroxyethyl starch after trauma-hemorrhagic shock: restoration of macrophage integrity and prevention of increased circulating interleukin-6 levels

OBJECTIVES

To determine the effects of resuscitation with the colloidal solution (hydroxyethyl starch) vs. crystalloid solution on cell-mediated immune functions after trauma-hemorrhage.

DESIGN

Prospective, multiexperimental, randomized, controlled study.

SETTING

University research laboratory.

SUBJECTS

Thirty-six inbred male C3H/HEN (endotoxin-sensitive) mice, aged 6 to 7 wks, and weighing 18 to 23 g.

INTERVENTIONS

Crystalloid (lactated Ringer's solution) with and without 6% hydroxyethyl starch after trauma-hemorrhage.

MEASUREMENTS AND MAIN RESULTS

Mice underwent laparotomy, were bled to and maintained at a blood pressure of 40 mm Hg for 60 mins, then resuscitated with either 4x the shed blood volume as lactated Ringer's solution or 2x the shed blood volume as lactated Ringer's solution plus 1 x 6% hydroxyethyl starch. Sham mice were neither hemorrhaged nor resuscitated. At 2 or 24 hrs posthemorrhage, serum, splenocytes, peritoneal macrophages, and splenic macrophages were obtained. Bioassays were used to determine interleukin-2, interleukin-3, and interleukin-6 concentrations, while splenocyte proliferation was assessed by 3H-thymidine incorporation. Trauma-hemorrhage markedly depressed splenocyte proliferation, interleukin-6 release by macrophages, and lymphokine release at 2 and 24 hrs postresuscitation. The combination of lactated Ringer's solution and hydroxyethyl starch neither restored, nor exacerbated lymphocyte functions. Interleukin-6 release by peritoneal macrophages was restored 24 hrs after hydroxyethyl starch infusion; serum interleukin-6 concentrations remained at sham levels.

CONCLUSIONS

Since the use of lactated Ringer's solution and hydroxyethyl starch after hemorrhage did not adversely affect cell-mediated immune functions, but produced salutary effects on macrophage functions, hydroxyethyl starch is a safe and beneficial resuscitation adjunct.

Replacement of major surgical blood loss by hypo-oncotic or conventional plasma substitutes

The purpose of the study was to examine the effects of hypooncotic 4% hydroxyethyl starch 120/0.7, 3% dextran 70, 5% albumin and hyperoncotic 6% hydroxyethyl starch 120/0.7 on the perioperative colloid osmotic pressure (COP), albumin and protein concentrations and fluid balance. The plasma substitutes were used with red cell concentrates to replace blood loss with equal volume in sixty major abdominal or urological surgeries. A special effort was made to keep replacements and losses at even volumes constantly and to avoid fluctuation of blood volume. The blood specimen were obtained before induction, after each 20% blood loss, at the end of the recovery room phase and on the three following postoperative mornings. There were significant differences in the peroperative and immediate postoperative COPs. However, these differences had vanished by the first postoperative morning. COP was preserved above 16 mmHg in all groups throughout the study. The identical peroperative albumin and protein concentrations of the synthetic colloid groups suggests that their volume effect was the same, regardless of the varying COP. During the observation period there were no significant differences among the groups concerning the diuresis and the fluid balances. We conclude, that the hypooncotic 4% HES 120 and 3% dextran 70 solutions provide the same clinical effect as 6% HES 120 solution. Consequently less colloid is needed, which allows the use of greater volumes of the dilute colloid solutions in replacement therapy.

Coagulopathy with the use of hetastarch in the treatment of vasospasm

The use of colloid agents to achieve hypervolemia in the prevention and treatment of postsubarachnoid hemorrhage (post-SAH) vasospasm is included in the standard of care at many institutions. Risk profiles are necessary to ensure appropriate use of these agents. In a series of 85 patients with recent aneurysmal SAH, 26 developed clinical symptoms of vasospasm. Fourteen of the 26 were treated with hetastarch for volume expansion while the other 12 received plasma protein fraction (PPF). Clinically significant bleeding pathologies were noted in six patients who received hetastarch as a continuous intravenous infusion. Hetastarch increased partial thromboplastin time from a mean of 23.9 seconds to a mean of 33.1 seconds (p < 0.001) in all patients who received infusions of this agent, while no effect was noted in the 12 patients who received PPF infusions. No other coagulation parameters were altered. This study shows an increase in coagulopathy with the use of hetastarch as compared with the use of PPF for the treatment of postaneurysmal vasospasm.

Hypovolemic shock and resuscitation

Hypovolemic shock is the manifestation of hypoperfusion from inadequate intravascular volume resulting in cellular hypoxia. Early, effective treatment tailored to the individual patient will minimize morbidity and mortality. The causes and end-organ responses can differ with each patient, requiring an understanding of the underlying physiology and pathophysiology. Treatment always consists of oxygen and isotonic crystalloids and may require the use of colloids, corticosteroids, antibiotics, and vasomotor drugs.

The use of hetastarch as adjunct therapy in 26 dogs with hypoalbuminemia: a phase two clinical trial

The purpose of this study was to evaluate the safety and efficacy of the synthetic colloid hetastarch in dogs with hypoalbuminemia. Individual doses of hetastarch ranged from 9 to 27 mL/kg, and multiple doses were used frequently. Total doses ranged from 9 to 59 mL/kg. Colloid oncotic pressure was measured in 13 dogs before and after treatment. Mean colloid oncotic pressure +/- SD was 9.32 +/- 2.35 mm Hg before treatment and 16.41 +/- 1.61 mm Hg in 8 healthy pet dogs used as controls. The difference in these values was significant (P < .001). There was a significant increase in mean colloid oncotic pressure after the first dose of hetastarch, but there was no relationship between the dose of hetastarch and the magnitude of increase in colloid oncotic pressure. Peripheral edema or body cavity transudates resolved or decreased in 83% of the dogs despite concurrent use of crystalloid fluid therapy. There was also no relationship between the dose of hetastarch and resolution of edema. Worsening of the results from coagulograms occurred in 5 of 18 dogs, and included increased prothrombin time (n = 1), increased partial thromboplastin time (n = 5), and decreased platelet count (n = 3). Bleeding that occurred in 3 dogs could not be directly attributed to the hetastarch. There was no relationship between the dose of hetastarch and worsening of the values in the coagulograms.

Hydroxyethyl starch as a prime for cardiopulmonary bypass: effects of two different solutions on haemostasis

Hydroxyethyl starch (HES) is efficacious as a volume expander in cardiac surgical patients, but it may impair the haemostatic mechanisms. However, this latter effect may be less conspicuous with low molecular weight (LMW) solutions than with high molecular weight (HMW) solutions. Therefore, LMW- and HMW-HES solutions were evaluated as priming solutions for cardiopulmonary bypass (CPB) with respect to their effect on haemostasis. Forty-five patients undergoing coronary bypass grafting were prospectively randomised to three groups and received in a double-blind manner as their CPB prime either 20 ml.kg-1 LMW-HES (Mw 120,000), 20 ml.kg-1 HMW-HES (Mw 400,000) or Ringer's acetate 2000 ml. The final volume of the prime was completed to 2000 ml with Ringer's acetate in the HES groups. Anaesthesia and CPB management were standardised. Plasma levels of von Willebrand factor antigen and factor VIII procoagulant activity were significantly more depressed after CPB in both HES-groups as compared with the crystalloid prime group. In addition, APTT was more prolonged and the maximal amplitude of thromboelastographic tracing was more decreased in the HES-groups. It is concluded that it may be advisable to avoid HES solutions in the CPB prime, especially in patients with an increased risk for bleeding after cardiac operations.

Intraoperative fluid management

The surgeon should be cognizant of both the intraoperative and postoperative consequences of intraoperative fluid administration. Optimal fluid management should take into consideration the patient's overall condition and should not be based solely on the cardiovascular response to volume loading. The selection of a particular fluid for resuscitation solution should be tailored to the patient's individual situation. No single fluid preparation will be appropriate for all clinical situations. Crystalloids, colloids, and hypertonic saline solutions have all been shown to be effective in restoring intravascular volume. Each has its own relative advantages and disadvantages and will be appropriate in differing situations. Colloid preparations should not be avoided for fear of inducing pulmonary edema, and the use of hypertonic solutions should not be precluded by fear of potential metabolic complications. The judicious use of both hypertonic solutions and colloids is safe. For the vast majority of routine surgical cases, where the patient is hemodynamically stable and postoperative fluid overloading is not a significant problem, isotonic crystalloids such as lactated Ringer's are both sufficient and cost effective.