Cardiopulmonary bypass priming using a high dose of a balanced hydroxyethyl starch versus an albumin-based priming strategy

Hydroxyethyl Starch-Bovine Hemoglobin Conjugate as an Effective Oxygen Carrier with the Ability to Expand Plasma

Hemorrhagic shock leads to intravasal volume deficiency, tissue hypoxia, and cellular anaerobic metabolism. Hemoglobin (Hb) could deliver oxygen for hypoxic tissues but is unable to expand plasma. Hydroxyethyl starch (HES) could compensate for the intravasal volume deficiency but cannot deliver oxygen. Thus, bovine Hb (bHb) was conjugated with HES (130 kDa and 200 kDa) to develop an oxygen carrier with the ability to expand plasma. Conjugation with HES increased the hydrodynamic volume, colloidal osmotic pressure, and viscosity of bHb. It slightly perturbed the quaternary structure and heme environment of bHb. The partial oxygen pressures at 50% saturation (P ₅₀) of the two conjugates (bHb-HES130 and bHb-HES200) were 15.1 and 13.9 mmHg, respectively. The two conjugates showed no apparent side effects on the morphology and rigidity, hemolysis, and platelet aggregation of red blood cells of Wistar rats. Thus, bHb-HES130 and bHb-HES200 were expected to function as an effective oxygen carrier with the ability to expand plasma.

Fraud and retraction in perioperative medicine publications: what we learned and what can be implemented to prevent future recurrence

Fraud in medical publications is an increasing concern. In particular, disciplines related to perioperative medicine-including anaesthesia and critical care-currently hold the highest rankings in terms of retracted papers for research misconduct. The dominance of this dubious achievement is attributable to a limited number of researchers who have repeatedly committed scientific fraud. In the last three decades, six researchers have authored 421 of the 475 papers retracted in perioperative medicine. This narrative review reports on six cases of fabricated publication in perioperative medicine that resulted in the paper's retraction. The process that led to the unveiling of the fraud, the impact on clinical practice, and changes in regulatory mechanisms of scientific companies and governmental agencies' policies are also presented. Fraud in medical publications is a growing concern that affects perioperative medicine requiring a substantial number of papers to be retracted. The continuous control elicited by readers, by local institutional review boards, scientific journal reviewers, scientific societies and government agencies can play an important role in preserving the 'pact of trust' between authors, professionals and ultimately the relationship between doctors and patients.

Effects of platelet-rich plasmapheresis during cardiovascular surgery: A meta-analysis of randomized controlled clinical trials

OBJECTIVE

This study aimed to explore the effects of platelet-rich plasmapheresis (PRP) on the amount of postoperative blood loss and the requirements for allogeneic fresh frozen plasma (FFP) and red blood cell (RBC) transfusions during cardiovascular surgery.

METHODS

A literature search of 7 online databases was conducted. Randomized control trials (RCT) comparing intraoperative PRP or appropriate control groups were considered suitable for this current study.

RESULTS

Fifteen RCTs enrolling a total of 1002 patients, including 501 patients who received PRP and 501 control patients. Meta-analysis of the data from these trials showed that PRP reduced the total volume of postoperative blood loss (standardized mean difference [SMD], -0.74; 95% confidence interval [CI], -1.18 to -0.31; P < 0.05), reduced postoperative fresh frozen plasma (FFP) transfusion (SMD, -0.38; 95%CI, -0.69 to -0.08; P < 0.05), reduced postoperative RBCs transfusion (SMD, -0.44; 95%CI, -0.77 to -0.10; P < 0.05), and reduced the proportion of patients receiving postoperative allogeneic RBC transfusions (relative risk [RR], 0.44; 95%CI, 0.21-0.91, P < 0.05) during cardiovascular surgery.

CONCLUSION

Conducting PRP before cardiopulmonary bypass (CPB) and transfusing autologous platelet-rich plasma (aPRP) after reversal of heparin could reduce postoperative blood loss, the requirements for blood products transfusion during cardiovascular surgery. A higher mean platelet count in aPRP may improve the final outcome. However, there was a high degree of undetermined heterogeneity among the analyzed trials, and larger and more precise RCTs are needed to confirm these conclusions.

Inaction over retractions of identified fraudulent publications: ongoing weakness in the system of scientific self-correction

Published articles may be retracted when their findings are no longer considered reliable due to honest error, publication misconduct, or research misconduct. This article focuses on the case of a single serial violator of research and publication ethics in anesthesiology and critical care, which is widely publicized. A chain of events led to detection of misconduct that had substantial impact on the evidence base for the safety of hydroxyethyl starch, an intravenous artificial colloid solution, which is reflected in current guidelines on fluid management and volume resuscitation. As citations to retracted works continue to be a cause for concern, this article reviews the retraction status of this author's published articles to determine whether sufficient action has been taken to retract his body of work. Results show that retraction practices are not uniform and that guidelines for retraction are still not being fully implemented, resulting in retractions of insufficient quantity and quality. As retractions continue to emerge for the author's publications, with ten more since 2011, and as they are generally increasing, these data on retractions not only provide findings of misconduct, but also allow us to make inferences about ongoing weaknesses in the system of scientific literature.

Acute Kidney Injury Following Cardiac Surgery in Neonates and Young Infants: Experience of a Single Center Using Novel Perioperative Strategies

OBJECTIVE

Acute kidney injury (AKI) following cardiac surgery is a serious complication with a reported incidence of 30% to 50%. This study sought to determine the prevalence and risk factors for AKI among neonates and young infants undergoing repair of cardiac defects at an institution using novel perioperative strategies.

METHODS

A retrospective analysis of 102 consecutive infants (<2 months) undergoing repair of cardiac defects on cardiopulmonary bypass formed the study group. Cardiac diagnoses were stratified according to the Society of Thoracic Surgeons Congenital Heart Surgery (STAT) mortality categories. The prevalence of AKI within 72 hours was defined according to the three-stage Acute Kidney Injury Network criteria. Novel bypass strategies to preserve renal function included maintenance of higher hematocrit and high flow rates on cardiopulmonary bypass despite systemic hypothermia, and avoidance of albumin and milrinone in the perioperative period.

RESULTS

Mean age was 24 ± 19 days. Eighteen patients were less than 7 days of age at the time of surgery. Patient distribution according to STAT categories was as follows: 1 (n = 21), 2 (n = 12), 3 (n = 22), 4 (n = 28), and 5 (n = 19). The incidence of stages 1, 2, and 3 AKI in the population was 8% (n = 9), 2% (n = 2), and 0% (n = 0), respectively. On multivariate analysis higher STAT category was the only significant risk factor for AKI.

CONCLUSION

Current incidence of AKI following cardiac surgery in young infants at our institution is low. Novel perioperative strategies may have contributed to the low observed incidence of AKI in our patient population. Increased complexity of heart disease was a risk factor for AKI.

Noncompliance with Human Subjects' Protection Requirements as a Reason for Retracting Papers: Survey of Retraction Notices on Medical Papers Published from 1981 to 2011

Though protection of human research subjects is universally recognized as a critical requirement for the ethical conduct of research, few studies have examined retractions of medical articles through apparent noncompliance with that requirement. From our survey of 99 retracted papers published from 1981 to 2011, we found that the basis for those decisions was poorly explained in retraction notices and that most of the articles continued to be cited. In retraction notices, the current manner of explaining failure to protect human subjects is misleading and confusing.

Ethical publishing in intensive care medicine: A narrative review

Ethical standards in the context of scientific publications are increasingly gaining attention. A narrative review of the literature concerning publication ethics was conducted as found in PubMed, Google Scholar, relevant news articles, position papers, websites and other sources. The Committee on Publication Ethics has produced guidelines and schedules for the handling of problem situations that have been adopted by professional journals and publishers worldwide as guidelines to authors. The defined requirements go beyond the disclosure of conflicts of interest or the prior registration of clinical trials. Recommendations to authors, editors and publishers of journals and research institutions were formulated with regard to issues of authorship, double publications, plagiarism, and conflicts of interest, with special attention being paid to unethical research behavior and data falsification. This narrative review focusses on ethical publishing in intensive care medicine. As scientific misconduct with data falsification damage patients and society, especially if fraudulent studies are considered important or favor certain therapies and downplay their side effects, it is important to ensure that only studies are published that have been carried out with highest integrity according to predefined criteria. For that also the peer review process has to be conducted in accordance with the highest possible scientific standards and making use of available modern information technology. The review provides the current state of recommendations that are considered to be most relevant particularly in the field of intensive care medicine.

Controversies in the use of hydroxyethyl starch solutions in small animal emergency and critical care

OBJECTIVES

To (1) review the development and medical applications of hydroxyethyl starch (HES) solutions with particular emphasis on its physiochemical properties; (2) critically appraise the available evidence in human and veterinary medicine, and (3) evaluate the potential risks and benefits associated with their use in critically ill small animals.

DATA SOURCES

Human and veterinary original research articles, scientific reviews, and textbook sources from 1950 to the present.

HUMAN DATA SYNTHESIS

HES solutions have been used extensively in people for over 30 years and ever since its introduction there has been a great deal of debate over its safety and efficacy. Recently, results of seminal trials and meta-analyses showing increased risks related to kidney dysfunction and mortality in septic and critically ill patients, have led to the restriction of HES use in these patient populations by European regulatory authorities. Although the initial ban on the use of HES in Europe has been eased, proof regarding the benefits and safety profile of HES in trauma and surgical patient populations has been requested by these same European regulatory authorities.

VETERINARY DATA SYNTHESIS

The veterinary literature is limited mostly to experimental studies and clinical investigations with small populations of patients with short-term end points and there is insufficient evidence to generate recommendations.

CONCLUSIONS

Currently, there are no consensus recommendations regarding the use of HES in veterinary medicine. Veterinarians and institutions affected by the HES restrictions have had to critically reassess the risks and benefits related to HES usage based on the available information and sometimes adapt their procedures and policies based on their reassessment. Meanwhile, large, prospective, randomized veterinary studies evaluating HES use are needed to achieve relevant levels of evidence to enable formulation of specific veterinary guidelines.

Editor's note: notice of retraction

In 2009, Joachim Boldt published an article in Anesthesia & Analgesia comparing albumin and hydroxyethyl starch priming cardiopulmonary bypass. The study was retracted in December 2010 for lack of IRB approval. A subsequent investigation by Klinikum Ludwigshafen determined that the study was fabricated. Based on the finding by Landesärztekammer Rheinland-Pfalz, the State Medical Association of Rheinland-Pfalz, that the studies were conducted without IRB approval, Anesthesia & Analgesia retracted 22 papers by Dr. Boldt in 2011 for unethical conduct of research. A subsequent investigation by Klinikum Ludwigshafen found that Boldt’s studies "failed to meet required standards," included "false data" in at least 10 studies, and found "clear evidence of procedural irregularities and research misconduct on the part of Dr. Joachim Boldt." In light of these concerns, Justus-Liebig Universität Giessen undertook an investigation of Dr. Boldt’s work from that institution. This investigation cast doubt on the veracity of Boldt J, Heesen M, Müller M, Pabsdorf M, Hempelmann G. The effects of albumin versus hydroxyethyl starch solution on cardiorespiratory and circulatory variables in critically ill patient. Anesth Analg 1996;83: 254–61. Based on evidence of data manipulation reported by Justus-Liebig Universität Giessen to the journal, this paper is hereby retracted.

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.

Catheter-based induction of renal ischemia/reperfusion in swine: description of an experimental model

Several techniques to induce renal ischemia have been proposed: clamp, PVA particles, and catheter-balloon. We report the development of a controlled, single-insult model of unilateral renal ischemia/reperfusion (I/R) without contralateral nephrectomy, using a suitable model, the pig. This is a balloon-catheter-based model using a percutaneous, interventional radiology procedure. One angioplasty balloon-catheter was placed into the right renal artery and inflated for 120 min and reperfusion over 24 h. Serial serums were sampled from the inferior vena cava and urine was directly sampled from the bladder throughout the experiment, and both kidneys were excised after 24 h of reperfusion. Analyses of renal structure and function were performed by hematoxylin-eosin/periodic Acid-Schiff, serum creatinine (SCr), blood urea nitrogen (BUN), fractional excretion of ions, and glucose, SDS-PAGE analysis of urinary proteins, and serum neutrophil gelatinase-associated lipocalin (NGAL). Total nitrated protein was quantified to characterize oxidative stress. Acute tubular necrosis (ATN) was identified in every animal, but only two animals showed levels of SCr above 150% of baseline values. As expected, I/R increased SCr and BUN. Fractional sodium, potassium, chloride, and bicarbonate excretion were modulated during ischemia. Serum-nitrated proteins and NGAL had two profiles: decreased with ischemia and increased after reperfusion. This decline was associated with increased protein excretion during ischemia and early reperfusion. Altogether, these data show that the renal I/R model can be performed by percutaneous approach in the swine model. This is a suitable translational model to study new early renal ischemic biomarkers and pathophysiological mechanisms in renal ischemia.

Neutrophil gelatinase associated lipocalin in acute kidney injury

BACKGROUND

Neutrophil gelatinase-associated lipocalin (NGAL) is a member of the lipocalin family of proteins. Usually, NGAL is produced and secreted by kidney tubule cells at low levels, but the amount produced and secreted into the urine and serum increases dramatically after ischemic, septic, or nephrotoxic injury of the kidneys. The purpose of our review article is to summarize the role of NGAL in acute kidney injury (AKI), emergent, and intensive care.

METHODS

A PubMed search was performed (only English-language articles concerning human subjects were considered) using each of the following search term combinations: neutrophil gelatinase-associated lipocalin OR NGAL and acute kidney injury OR AKI; cardiac surgery; heart failure OR cardiology; intensive care; emergency department OR emergency medicine; nephropathy OR nephrotoxicity and transplantation.

RESULTS

The results of our search yielded 339 articles. Of the 339 articles, 160 were eligible for review based on the predefined criteria for inclusion.

CONCLUSION

Based on the evidence reviewed, it is clear that patient NGAL level is an appropriate, sensitive, and specific early biomarker of AKI caused by a variety of different etiologies. It is advised that a multidisciplinary group of experts come together to make recommendations and propose a consensus of clinical procedures to advance the most efficacious NGAL monitoring protocol for early detection and treatment of patients with AKI.

Fraud in scientific research - birth of the Concordat to uphold research integrity in the United Kingdom

Fraud in research has risen exponentially and recent high profile cases may just be the tip of the iceberg. This threatens to have a major impact on public health, with policy makers and clinicians acting on erroneous data. To address this, the new research "Concordat", a consensus statement on research misconduct, has been published. Can it hold the key to rebuilding public confidence in scientific research in the United Kingdom? This review focuses on the concept of research misconduct, highlighting prominent cases and discussing strategies in order to restore confidence in the validity of scientific research.

Urinary glutathione S-transferases in the pathogenesis and diagnostic evaluation of acute kidney injury following cardiac surgery: a critical review

PURPOSE OF REVIEW

A focused review of the nature, source, physiological role and rapidly expanding evidence for glutathione S-transferase (GST) subtypes π and α as biomarkers of acute kidney injury (AKI) in patients undergoing cardiac surgery. Expanded insights into the site-specific expression of the GSTs in defined parts of the nephron during renal damage are presented, with particular emphasis on the pathogenesis of cardiac surgery and cardiopulmonary bypass (CPB)-associated AKI and the role of GSTs in oxygen radical disposal.

RECENT FINDINGS

Recent developments have highlighted a potential role of urinary α-GST and π-GST in the diagnostic evaluation of cardiac surgery-associated AKI. Both urinary α-GST and π-GST are detected in the postoperative period. π-GST performed best at predicting AKI severity at the time of the initial diagnosis of AKI. α-GST was able to predict the future development of both stage 1 and stage 3 AKI.

SUMMARY

The current data from a small number of patients suggest a potential role of urinary GSTs in the clinical diagnostic evaluation of AKI following cardiac surgery. The performance of the GSTs for the early diagnosis of AKI needs to be validated in larger multicentre studies and in other patient populations at increased risk of AKI (e.g. patients with acute transplant rejection, septic patients). Comparison with other emerging AKI biomarkers is required to continue the development of π-GST and α-GST. Finally, additional studies examining the pathophysiological role of the GSTs in minimizing oxygen free radical exposure in the renal tubules during CPB may shed further light into their role as promising biomarkers of cardiac surgery-associated AKI.

Do simple screening statistical tools help to detect reporting bias?

BACKGROUND

As a result of reporting bias, or frauds, false or misunderstood findings may represent the majority of published research claims. This article provides simple methods that might help to appraise the quality of the reporting of randomized, controlled trials (RCT).

METHODS

This evaluation roadmap proposed herein relies on four steps: evaluation of the distribution of the reported variables; evaluation of the distribution of the reported p values; data simulation using parametric bootstrap and explicit computation of the p values. Such an approach was illustrated using published data from a retracted RCT comparing a hydroxyethyl starch versus albumin-based priming for cardiopulmonary bypass.

RESULTS

Despite obvious nonnormal distributions, several variables are presented as if they were normally distributed. The set of 16 p values testing for differences in baseline characteristics across randomized groups did not follow a Uniform distribution on [0,1] (p = 0.045). The p values obtained by explicit computations were different from the results reported by the authors for the two following variables: urine output at 5 hours (calculated p value < 10-6, reported p ≥ 0.05); packed red blood cells (PRBC) during surgery (calculated p value = 0.08; reported p < 0.05). Finally, parametric bootstrap found p value > 0.05 in only 5 of the 10,000 simulated datasets concerning urine output 5 hours after surgery. Concerning PRBC transfused during surgery, parametric bootstrap showed that only the corresponding p value had less than a 50% chance to be inferior to 0.05 (3,920/10,000, p value < 0.05).

CONCLUSIONS

Such simple evaluation methods might offer some warning signals. However, it should be emphasized that such methods do not allow concluding to the presence of error or fraud but should rather be used to justify asking for an access to the raw data.

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.

Colloids versus crystalloids for fluid resuscitation in critically ill patients

BACKGROUND

Colloid solutions are widely used in fluid resuscitation of critically ill patients. There are several choices of colloid, and there is ongoing debate about the relative effectiveness of colloids compared to crystalloid fluids.

OBJECTIVES

To assess the effects of colloids compared to crystalloids for fluid resuscitation in critically ill patients.

SEARCH METHODS

We searched the Cochrane Injuries Group Specialised Register (17 October 2012), the Cochrane Central Register of Controlled Trials (The Cochrane Library) (Issue 10, 2012), MEDLINE (Ovid) 1946 to October 2012, EMBASE (Ovid) 1980 to October 2012, ISI Web of Science: Science Citation Index Expanded (1970 to October 2012), ISI Web of Science: Conference Proceedings Citation Index-Science (1990 to October 2012), PubMed (October 2012), www.clinical trials.gov and www.controlled-trials.com. We also searched the bibliographies of relevant studies and review articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of colloids compared to crystalloids, in patients requiring volume replacement. We excluded cross-over trials and trials involving pregnant women and neonates.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and rated quality of allocation concealment. We analysed trials with a 'double-intervention', such as those comparing colloid in hypertonic crystalloid to isotonic crystalloid, separately. We stratified the analysis according to colloid type and quality of allocation concealment.

MAIN RESULTS

We identified 78 eligible trials; 70 of these presented mortality data.COLLOIDS COMPARED TO CRYSTALLOIDS: Albumin or plasma protein fraction - 24 trials reported data on mortality, including a total of 9920 patients. The pooled risk ratio (RR) from these trials was 1.01 (95% confidence interval (CI) 0.93 to 1.10). When we excluded the trial with poor-quality allocation concealment, pooled RR was 1.00 (95% CI 0.92 to 1.09). Hydroxyethyl starch - 25 trials compared hydroxyethyl starch with crystalloids and included 9147 patients. The pooled RR was 1.10 (95% CI 1.02 to 1.19). Modified gelatin - 11 trials compared modified gelatin with crystalloid and included 506 patients. The pooled RR was 0.91 (95% CI 0.49 to 1.72). (When the trials by Boldt et al were removed from the three preceding analyses, the results were unchanged.) Dextran - nine trials compared dextran with a crystalloid and included 834 patients. The pooled RR was 1.24 (95% CI 0.94 to 1.65). COLLOIDS IN HYPERTONIC CRYSTALLOID COMPARED TO ISOTONIC CRYSTALLOID: Nine trials compared dextran in hypertonic crystalloid with isotonic crystalloid, including 1985 randomised participants. Pooled RR for mortality was 0.91 (95% CI 0.71 to 1.06).

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery. Furthermore, the use of hydroxyethyl starch might increase mortality. As colloids are not associated with an improvement in survival and are considerably more expensive than crystalloids, it is hard to see how their continued use in clinical practice can be justified.

Fluid resuscitation with 6% hydroxyethyl starch (130/0.4) in acutely ill patients: an updated systematic review and meta-analysis

BACKGROUND

Recent research suggests that 6% hydroxyethyl starch (HES) 130/0.4 is one of the most frequently used resuscitation fluids worldwide. The retraction of studies evaluating its use necessitates a reevaluation of available evidence regarding its safety and efficacy.

METHODS

We performed a systematic review and meta-analysis of unretracted randomized controlled trials comparing the effects of 6% HES 130/0.4 with other colloid or crystalloid solutions on mortality, acute kidney injury/failure, and bleeding in acutely ill or perioperative patients. A sensitivity analysis including the data from retracted studies was also conducted.

RESULTS

Overall, 36 studies reporting 2149 participants met the inclusion criteria, of which 11 (n = 541) have been retracted. Of the remaining 25 studies, there was a high risk of bias in 17 studies; 19 studies (n = 1246) were conducted in perioperative patients and 6 (n = 362) in critically ill patients. Sixteen studies reported mortality: 104 deaths in 1184 participants. The relative risk of death was 0.95 (95% confidence interval 0.64-1.42, I(2) = 0%, P = 0.73); including the retracted studies added a further 14 deaths and the relative risk was 0.92 (95% confidence interval 0.63-1.34, I(2) = 0%, P = 0.95). The data reporting acute kidney injury, red blood cell transfusion, and bleeding were of insufficient quantity and quality and not amenable to meta-analysis.

CONCLUSIONS

Published studies are of poor quality and report too few events to reliably estimate the benefits or risks of administering 6% HES 130/0.4. This same conclusion is reached with or without the retracted studies. Given the widespread use of 6% HES 130/0.4, high-quality trials reporting a large number of events are urgently required.

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.

Colloids versus crystalloids for fluid resuscitation in critically ill patients

BACKGROUND

Colloid solutions are widely used in fluid resuscitation of critically ill patients. There are several choices of colloid and there is ongoing debate about the relative effectiveness of colloids compared to crystalloid fluids.

OBJECTIVES

To assess the effects of colloids compared to crystalloids for fluid resuscitation in critically ill patients.

SEARCH METHODS

We searched the Cochrane Injuries Group Specialised Register (searched 16 March 2012), Cochrane Central Register of Controlled Trials 2011, issue 3 (The Cochrane Library), MEDLINE (Ovid) 1946 to March 2012, Embase (Ovid) 1980 to March 2012, ISI Web of Science: Science Citation Index Expanded (1970 to March 2012), ISI Web of Science: Conference Proceedings Citation Index-Science (1990 to March 2012), PubMed (searched 16 March 2012), www.clinical trials.gov and www.controlled-trials.com. We also searched the bibliographies of relevant studies and review articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of colloids compared to crystalloids, in patients requiring volume replacement. We excluded cross-over trials and trials in pregnant women and neonates.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and rated quality of allocation concealment. We analysed trials with a 'double-intervention', such as those comparing colloid in hypertonic crystalloid to isotonic crystalloid, separately. We stratified the analysis according to colloid type and quality of allocation concealment.

MAIN RESULTS

We identified 74 eligible trials; 66 of these presented mortality data.Colloids compared to crystalloids Albumin or plasma protein fraction - 24 trials reported data on mortality, including a total of 9920 patients. The pooled relative risk (RR) from these trials was 1.01 (95% confidence interval (CI) 0.93 to 1.10). When we excluded the trial with poor quality allocation concealment, pooled RR was 1.00 (95% CI 0.92 to 1.09). Hydroxyethyl starch - 21 trials compared hydroxyethyl starch with crystalloids, n = 1385 patients. The pooled RR was 1.10 (95% CI 0.91 to 1.32). Modified gelatin - 11 trials compared modified gelatin with crystalloid, n = 506 patients. The pooled RR was 0.91 (95% CI 0.49 to 1.72). (When the trials by Boldt et al were removed from the three preceding analyses, the results were unchanged.) Dextran - nine trials compared dextran with a crystalloid, n = 834 patients. The pooled RR was 1.24 (95% CI 0.94 to 1.65).Colloids in hypertonic crystalloid compared to isotonic crystalloid Nine trials compared dextran in hypertonic crystalloid with isotonic crystalloid, including 1985 randomised participants. Pooled RR was 0.91 (95% CI 0.71 to 1.06).

AUTHORS' CONCLUSIONS

There is no evidence from RCTs that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery. As colloids are not associated with an improvement in survival, and as they are more expensive than crystalloids, it is hard to see how their continued use in these patients can be justified outside the context of RCTs.

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.

Retracted publications in the drug literature

Recent studies have suggested an increase in the number of retracted scientific publications. It is unclear how broadly the issue of misleading and fraudulent publications pertains to retractions of drug therapy studies. Therefore, we sought to determine the trends and factors associated with retracted publications in drug therapy literature. A PubMed search was conducted to identify retracted drug therapy articles published from 2000-2011. Articles were grouped according to reason for retraction, which was classified as scientific misconduct or error. Scientific misconduct was further divided into data fabrication, data falsification, questions of data veracity, unethical author conduct, and plagiarism. Error was defined as duplicate publication, scientific mistake, journal error, or unstated reasons. Additional data were extracted from the retracted articles, including type of article, funding source, author information, therapeutic area, and retraction issue. A total of 742 retractions were identified from 2000-2011 in the general biomedical literature, and 102 drug studies met our inclusion criteria. Of these, 73 articles (72%) were retracted for a reason classified as scientific misconduct, whereas 29 articles (28%) were retracted for error. Among the 73 articles classified as scientific misconduct, those classified as unethical author conduct (32 articles [44%]) and data fabrication (24 articles [33%]) constituted the majority. The median time from publication of the original article to retraction was 31 months (range 1-130). Fifty percent of retracted articles did not state a funding source, whereas pharmaceutical manufacturer funding accounted for only 13 articles (13%) analyzed. Many retractions were due to repeat offenses by a small number of authors, with nearly 40% of the retracted studies associated with two individuals. We found that a greater proportion of drug therapy articles were retracted for reasons of misconduct and fraud compared with other biomedical studies. It is important for health care practitioners to monitor the literature for retractions so that recommendations for drug therapy and patient management may be modified accordingly.

Marking renal injury: can we move beyond serum creatinine?

Acute kidney injury (AKI) is a prevalent and devastating condition associated with significant morbidity and mortality. Despite marked improvements in clinical care, the outcomes for subjects with AKI have shown limited improvement in the past 50 years. A major factor inhibiting clinical progress in this field has been the inability to accurately predict and diagnose early kidney dysfunction. The current gold standard clinical and biochemical criteria for diagnosis of AKI, Risk Injury Failure Loss End-stage renal disease, and its modification, Acute Kidney Injury Network criteria, rely on urine output and serum creatinine, which are insensitive, nonspecific, and late markers of disease. The recent development of a variety of analytic mass spectrometry-based platforms have enabled separation, characterization, detection, and quantification of proteins (proteomics) and metabolites (metabolomics). These high-throughput platforms have raised hopes of identifying novel protein and metabolite markers, and recent efforts have led to several promising novel markers of AKI. However, substantial challenges remain, including the need to systematically evaluate incremental performance of these markers over and beyond current clinical and biochemical criteria for AKI. We discuss the basic issues surrounding AKI biomarker development, highlight the most promising markers currently under development, and discuss the barriers toward widespread clinical implementation of these markers.

Neutrophil gelatinase-associated lipocalin in acute kidney injury

Acute kidney injury (AKI) is recognized as an independent risk factor for morbidity and mortality. Unfortunately, this syndrome was historically underdiagnosed due to inconsistent definition of AKI as well as insensitive and nonspecific diagnostic tools. Recent advances in defining AKI, understanding its pathophysiology, and improving its diagnostic accuracy have an impact in disease management and clinical outcome. Prompt recognition and treatment of AKI still remains the cornerstone of clinical management of this syndrome. This chapter focuses on the recent advances in diagnosis of AKI using novel serum and urine biomarkers. The role of neutrophil gelatinase-associated lipocalin (NGAL) in pathophysiology and diagnosis of AKI is presented. A detailed analysis of the biology of NGAL and presentation of laboratory methods of measurement is also provided. The role of NGAL as biomarker beyond the boundaries of nephrology is also presented.

Human albumin solution for resuscitation and volume expansion in critically ill patients

BACKGROUND

Human albumin solutions are used for a range of medical and surgical problems. Licensed indications are the emergency treatment of shock and other conditions where restoration of blood volume is urgent, such as in burns and hypoproteinaemia. Human albumin solutions are more expensive than other colloids and crystalloids.

OBJECTIVES

To quantify the effect on mortality of human albumin and plasma protein fraction (PPF) administration in the management of critically ill patients.

SEARCH METHODS

We searched the Cochrane Injuries Group Specialised Register (searched 31 May 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 2), MEDLINE (Ovid) (1948 to week 3 May 2011), EMBASE (Ovid) (1980 to Week 21 2011), CINAHL (EBSCO) (1982 to May 2011), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) (1970 to May 2011), ISI Web of Science: Conference Proceedings Citation Index - Science (CPCI-S) (1990 to May 2011), PubMed (www.ncbi.nlm.nih.gov/sites/entrez/) (searched 10 June 2011, limit: last 60 days). Reference lists of trials and review articles were checked, and authors of identified trials were contacted.

SELECTION CRITERIA

Randomised controlled trials comparing albumin or PPF with no albumin or PPF or with a crystalloid solution in critically ill patients with hypovolaemia, burns or hypoalbuminaemia.

DATA COLLECTION AND ANALYSIS

We collected data on the participants, albumin solution used, mortality at the end of follow up, and quality of allocation concealment. Analysis was stratified according to patient type.

MAIN RESULTS

We found 38 trials meeting the inclusion criteria and reporting death as an outcome. There were 1,958 deaths among 10,842 trial participants.For hypovolaemia, the relative risk of death following albumin administration was 1.02 (95% confidence interval (CI) 0.92 to 1.13). This estimate was heavily influenced by the results of the SAFE trial, which contributed 75.2% of the information (based on the weights in the meta-analysis). For burns, the relative risk was 2.93 (95% CI 1.28 to 6.72) and for hypoalbuminaemia the relative risk was 1.26 (95% CI 0.84 to 1.88). There was no substantial heterogeneity between the trials in the various categories (Chi(2) = 26.66, df = 31, P = 0.69). The pooled relative risk of death with albumin administration was 1.05 (95% CI 0.95 to 1.16).

AUTHORS' CONCLUSIONS

For patients with hypovolaemia, there is no evidence that albumin reduces mortality when compared with cheaper alternatives such as saline. There is no evidence that albumin reduces mortality in critically ill patients with burns and hypoalbuminaemia. The possibility that there may be highly selected populations of critically ill patients in which albumin may be indicated remains open to question. However, in view of the absence of evidence of a mortality benefit from albumin and the increased cost of albumin compared to alternatives such as saline, it would seem reasonable that albumin should only be used within the context of well concealed and adequately powered randomised controlled trials.

Human albumin solution for resuscitation and volume expansion in critically ill patients

BACKGROUND

Human albumin solutions are used for a range of medical and surgical problems. Licensed indications are the emergency treatment of shock and other conditions where restoration of blood volume is urgent, such as in burns and hypoproteinaemia. Human albumin solutions are more expensive than other colloids and crystalloids.

OBJECTIVES

To quantify the effect on mortality of human albumin and plasma protein fraction (PPF) administration in the management of critically ill patients.

SEARCH STRATEGY

We searched the Cochrane Injuries Group Specialised Register (searched 31 May 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 2), MEDLINE (Ovid) (1948 to week 3 May 2011), EMBASE (Ovid) (1980 to Week 21 2011), CINAHL (EBSCO) (1982 to May 2011), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) (1970 to May 2011), ISI Web of Science: Conference Proceedings Citation Index - Science (CPCI-S) (1990 to May 2011), PubMed (www.ncbi.nlm.nih.gov/sites/entrez/) (searched 10 June 2011, limit: last 60 days). Reference lists of trials and review articles were checked, and authors of identified trials were contacted.

SELECTION CRITERIA

Randomised controlled trials comparing albumin or PPF with no albumin or PPF or with a crystalloid solution in critically ill patients with hypovolaemia, burns or hypoalbuminaemia.

DATA COLLECTION AND ANALYSIS

We collected data on the participants, albumin solution used, mortality at the end of follow up, and quality of allocation concealment. Analysis was stratified according to patient type.

MAIN RESULTS

We found 38 trials meeting the inclusion criteria and reporting death as an outcome. There were 1,958 deaths among 10,842 trial participants.For hypovolaemia, the relative risk of death following albumin administration was 1.02 (95% confidence interval (CI) 0.92 to 1.13). This estimate was heavily influenced by the results of the SAFE trial, which contributed 75.2% of the information (based on the weights in the meta-analysis). For burns, the relative risk was 2.93 (95% CI 1.28 to 6.72) and for hypoalbuminaemia the relative risk was 1.26 (95% CI 0.84 to 1.88). There was no substantial heterogeneity between the trials in the various categories (Chi(2) = 26.66, df = 31, P = 0.69). The pooled relative risk of death with albumin administration was 1.05 (95% CI 0.95 to 1.16).

AUTHORS' CONCLUSIONS

For patients with hypovolaemia, there is no evidence that albumin reduces mortality when compared with cheaper alternatives such as saline. There is no evidence that albumin reduces mortality in critically ill patients with burns and hypoalbuminaemia. The possibility that there may be highly selected populations of critically ill patients in which albumin may be indicated remains open to question. However, in view of the absence of evidence of a mortality benefit from albumin and the increased cost of albumin compared to alternatives such as saline, it would seem reasonable that albumin should only be used within the context of well concealed and adequately powered randomised controlled trials.

Biomarkers for the early detection of acute kidney injury

PURPOSE OF REVIEW

Acute kidney injury (AKI) is a common and serious condition, the diagnosis of which depends on serum creatinine, which is a delayed and unreliable indicator of AKI. Fortunately, understanding the early stress response of the kidney to acute injuries has revealed a number of potential biomarkers. The current status of the most promising of these novel AKI biomarkers, including neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver-type fatty acid binding protein (L-FABP), and interleukin (IL)-18, is reviewed.

RECENT FINDINGS

In particular, NGAL is emerging as an excellent biomarker in the urine and plasma, for the early prediction of AKI, for monitoring clinical trials in AKI, and for the prognosis of AKI in several common clinical scenarios. However, biomarker combinations may be required to improve our ability to predict AKI and its outcomes in a context-specific manner.

SUMMARY

It is vital that additional large future studies demonstrate the association between biomarkers and hard clinical outcomes independent of serum creatinine concentrations and that randomization to a treatment for AKI based on high biomarker levels results in an improvement in clinical outcomes.

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.

Colloids versus crystalloids for fluid resuscitation in critically ill patients

BACKGROUND

Colloid solutions are widely used in fluid resuscitation of critically ill patients. There are several choices of colloid and there is ongoing debate about the relative effectiveness of colloids compared to crystalloid fluids.

OBJECTIVES

To assess the effects of colloids compared to crystalloids for fluid resuscitation in critically ill patients.

SEARCH STRATEGY

We searched the Cochrane Injuries Group Specialised Register, CENTRAL (The Cochrane Library 2008, Issue 3), MEDLINE, EMBASE, ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Conference Proceedings Citation Index-Science (CPCI-S), and The Controlled Trials metaRegister (www.controlled-trials.com). Reference lists of relevant studies and review articles were searched for further trials. The searches were last updated in September 2008.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of colloids compared to crystalloids, in patients requiring volume replacement. We excluded cross-over trials and trials in pregnant women and neonates.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and rated quality of allocation concealment. We analysed trials with a 'double-intervention', such as those comparing colloid in hypertonic crystalloid to isotonic crystalloid, separately. We stratified the analysis according to colloid type and quality of allocation concealment.

MAIN RESULTS

We identified 65 eligible trials; 56 of these presented mortality data.Colloids compared to crystalloidsAlbumin or plasma protein fraction - 23 trials reported data on mortality, including a total of 7754 patients. The pooled relative risk (RR) from these trials was 1.01 (95% confidence interval (95% CI) 0.92 to 1.10). When we excluded the trial with poor quality allocation concealment, pooled RR was 1.00 (95% CI 0.91 to 1.09). Hydroxyethyl starch - 17 trials compared hydroxyethyl starch with crystalloids, n = 1172 patients. The pooled RR was 1.18 (95% CI 0.96 to 1.44). Modified gelatin - 11 trials compared modified gelatin with crystalloid, n = 506 patients. The pooled RR was 0.91 (95% CI 0.49 to 1.72). (When the trials by Boldt et al were removed from the three preceding analyses, the results were unchanged.) Dextran - nine trials compared dextran with a crystalloid, n = 834 patients. The pooled RR was 1.24 (95% CI 0.94 to 1.65).Colloids in hypertonic crystalloid compared to isotonic crystalloidEight trials compared dextran in hypertonic crystalloid with isotonic crystalloid, including 1283 randomised participants. Pooled RR was 0.88 (95% CI 0.74 to 1.05).

AUTHORS' CONCLUSIONS

There is no evidence from RCTs that resuscitation with colloids reduces the risk of death, compared to resuscitation with crystalloids, in patients with trauma, burns or following surgery. As colloids are not associated with an improvement in survival, and as they are more expensive than crystalloids, it is hard to see how their continued use in these patients can be justified outside the context of RCTs.

Anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death.

OBJECTIVES

To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death.

SEARCH STRATEGY

We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. This version of the review includes a sensitivity analysis excluding trials authored by Prof. Joachim Boldt.

MAIN RESULTS

This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008).

AUTHORS' CONCLUSIONS

Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

Platelet-rich-plasmapheresis for minimising peri-operative allogeneic blood transfusion

BACKGROUND

Concerns regarding the safety of transfused blood have generated considerable enthusiasm for the use of technologies intended to reduce the use of allogeneic blood (blood from an unrelated donor). Platelet-rich plasmapheresis (PRP) offers an alternative approach to blood conservation.

OBJECTIVES

To examine the evidence for the efficacy of PRP in reducing peri-operative allogeneic red blood cell (RBC) transfusion, and the evidence for any effect on clinical outcomes such as mortality and re-operation rates.

SEARCH STRATEGY

We identified studies by searching MEDLINE (1950 to 2009), EMBASE (1980 to 2009), The Cochrane Library (Issue 1, 2009), the Internet (to March 2009) and the reference lists of published articles, reports, and reviews.

SELECTION CRITERIA

Controlled parallel group trials in which adult patients, scheduled for non-urgent surgery, were randomised to PRP, or to a control group which did not receive the intervention.

DATA COLLECTION AND ANALYSIS

Primary outcomes measured were: the number of patients exposed to allogeneic RBC transfusion, and the amount of RBC transfused. Other outcomes measured were: the number of patients exposed to allogeneic platelet transfusions, fresh frozen plasma, and cryoprecipitate, blood loss, re-operation for bleeding, post-operative complications (thrombosis), mortality, and length of hospital stay. Treatment effects were pooled using a random-effects model. Trial quality was assessed using criteria proposed by Schulz et al (Schulz 1995).

MAIN RESULTS

Twenty-two trials of PRP were identified that reported data for the number of patients exposed to allogeneic RBC transfusion. These trials evaluated a total of 1589 patients. The relative risk (RR) of exposure to allogeneic blood transfusion in those patients randomised to PRP was 0.73 (95%CI 0.59 to 0.90), equating to a relative risk reduction (RRR) of 27% and a risk difference (RD) of 19% (95%CI 10% to 29%). However, significant heterogeneity of treatment effect was observed (p < 0.00001; I² = 79%). When the four trials by Boldt are excluded, the RR is 0.76 (95% CI 0.62 to 0.93). On average, PRP did not significantly reduce the total volume of RBC transfused (weighted mean difference [WMD] -0.69, 95%CI -1.93 to 0.56 units). Trials provided inadequate data regarding the impact of PRP on morbidity, mortality, and hospital length of stay. Trials were generally small and of poor methodological quality.

AUTHORS' CONCLUSIONS

Although the results suggest that PRP is effective in reducing allogeneic RBC transfusion in adult patients undergoing elective surgery, there was considerable heterogeneity of treatment effects and the trials were of poor methodological quality. The available studies provided inadequate data for firm conclusions to be drawn regarding the impact of PRP on clinically important endpoints.

A systematic review of third-generation hydroxyethyl starch (HES 130/0.4) in resuscitation: safety not adequately addressed

BACKGROUND

Hydroxyethyl starches (HES) are widely used for intravascular volume therapy in surgical, emergency, and intensive care patients. There are safety concerns with regard to coagulopathy, renal failure, pruritus, tissue storage, and mortality. Third-generation HES 130/0.4 is considered to have an improved risk profile. A common rationale for the use of HES is the belief that 3 to 4 times more crystalloid than colloid volume is needed to achieve similar hemodynamic end points. Our goal was to assess whether published studies on HES 130/0.4 resuscitation are sufficiently well designed to draw conclusions about the safety of this compound. In addition, we wanted to assess crystalloid-to-colloid fluid ratios in studies with goal-directed fluid regimen.

METHODS

Systematic review of randomized controlled trials in which HES 130/0.4 is used for resuscitation.

RESULTS

We identified 56 randomized controlled trials (RCTs) with HES 130/0.4 in. acute hypovolemia, mainly from the elective surgical setting (n = 45). Surgical studies were small-sized (median 25 patients in the HES groups, range 10 to 90) and of short duration (median 12 hours, range 0.5 to 144 hours). The median cumulative HES dose was 2465 mL (range 328 to 6229 mL), corresponding to 35 mL/kg in a 70-kg patient, the daily dose limit being 50 mL/kg. End points mostly addressed variable surrogate outcomes. Sixty percent of control fluids were other HES solutions, gelatins, or dextran, which have a similar risk profile. Without exception, these studies were not designed for clinically important safety outcomes, primarily because they were too small, used mostly inadequate control fluids, and had inappropriately short observation periods. Therefore, and also because of heterogeneity of patient groups and outcome definitions, results from these studies cannot be pooled. These studies do not allow any conclusion about the safety of HES 130/0.4. There is a common belief that 3 to 4 times more crystalloid than colloid volume is necessary to achieve similar hemodynamic effects. We found a considerably lower ratio in surgical studies (mean 1.8, SD 0.1).

CONCLUSIONS

In summary, the extent of fluid load reduction that can be achieved by HES 130/0.4 is overestimated. Use of older HES solutions may be associated with serious side effects, and clinicians should be aware that there is no convincing evidence that third-generation HES 130/0.4 is safe in surgical, emergency, or intensive care patients despite publication of numerous clinical studies.