Gelatin and Hydroxyethyl Starch, but Not Albumin, Impair Hemostasis After Cardiac Surgery

Perioperative fluid management for adult cardiac surgery: network meta-analysis pooling on twenty randomised controlled trials

BACKGROUND

The aim of this study was to evaluate colloids and crystalloids used in perioperative fluid therapy for cardiac surgery patients to further investigate the optimal management strategies of different solutions.

METHOD

RCTs about adult surgical patients allocated to receive perioperative fluid therapy for electronic databases, including Ovid MEDLINE, EMBase, and Cochrane Central Register of Controlled Trials, were searched up to February 15, 2023.

RESULTS

None of the results based on network comparisons, including mortality, transfuse PLA, postoperative chest tube output over the first 24 h following surgery, and length of hospital stay, were statistically significant. Due to the small number of included studies, the results, including acute kidney injury, serum creatinine, serum microglobulin, and blood urea nitrogen, are from the direct comparison. For transfusion of RBCs, significant differences were observed in the comparisons of 3% gelatine vs. 6% HES 200/0.5, 4% albumin vs. 5% albumin, 4% gelatine vs. 5% albumin, 5% albumin vs. 6% HES 200/0.5, and 6% HES 130/0.4 vs. 6% HES 200/0.5. In transfusion of FFP, significant differences were observed in comparisons of 3% gelatine vs. 4% gelatine, 3% gelatine vs. 6% HES 200/0.5, 5% albumin vs. 6% HES 200/0.5, 4% gelatine vs. 5% albumin, 4% gelatine vs. 6% HES 200/0.4, and 6% HES 130/0.4 vs. 6% HES 200/0.5. For urinary output at 24 h after surgery, the results are deposited in the main text.

CONCLUSION

This study showed that 3% gelatin and 5% albumin can reduce the transfuse RBC and FFP. In addition, the use of hypertonic saline solution can increase urine output, and 5% albumin and 6% HES can shorten the length of ICU stay. However, none of the perioperative fluids showed an objective advantage in various outcomes, including mortality, transfuse PLA, postoperative chest tube output over the first 24 h following surgery, and length of hospital stay. The reliable and sufficient evidences on the injury of the kidney, including acute kidney injury, serum creatinine, serum microglobulin, and blood urea nitrogen, was still lacking. In general, perioperative fluids had advantages and disadvantages, and there were no evidences to support the recommendation of the optimal perioperative fluid for cardiac surgery.

Intravenous albumin in cardiac and vascular surgery: a systematic review and meta-analysis

BACKGROUND

Intravenous albumin is commonly utilised in cardiovascular surgery for priming of the cardiopulmonary bypass circuit, volume replacement, or both, although the evidence to support this practice is uncertain. The aim was to compare i.v. albumin with synthetic colloids and crystalloids for paediatric and adult patients undergoing cardiovascular surgery for all-cause mortality and other perioperative outcomes.

METHODS

A systematic review and meta-analysis of randomised controlled trials (RCTs) of i.v. albumin compared with synthetic colloids and crystalloids on the primary outcome of all-cause mortality was conducted. Secondary outcomes included renal failure, blood loss, duration of hospital or intensive care unit stay, cardiac index, and blood component use; subgroups were analysed by age, comparator fluid, and intended use (priming, volume, or both). We searched MEDLINE, Embase, and Cochrane Central Register of Controlled Trials (CCRT) from 1946 to November 23, 2022.

RESULTS

Of 42 RCTs, mortality was assessed in 15 trials (2711 cardiac surgery patients) and the risk difference was 0.00, 95% confidence interval (CI) -0.01 to 0.01, I2=0%. Among secondary outcomes, i.v. albumin resulted in smaller fluid balance, mean difference -0.55 L, 95% CI -1.06 to -0.4, I2=90% (nine studies, 1975 patients) and higher albumin concentrations, mean difference 7.77 g L-1, 95% CI 3.73-11.8, I2=95% (six studies, 325 patients).

CONCLUSIONS

Intravenous albumin use was not associated with a difference in morbidity and mortality in patients undergoing cardiovascular surgery, when compared with comparator fluids. The lack of improvement in important outcomes with albumin and its higher cost suggests it should be used restrictively.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO; CRD42020171876.

Effect of albumin usage during cardiopulmonary bypass on postoperative acute kidney injury in cardiac surgery patients: A historical cohort study

Introduction

Acute kidney injury (AKI) after cardiac surgery is a common and serious postoperative complication and is associated with an increased risk of mortality, morbidity, length of hospital stay, and costs. We evaluated the effect of albumin usage on postoperative AKI in patients who underwent on-pump Coronary Artery Bypass Graft Surgery (CABG).

Methods

This non-randomized cohort study was conducted on data from adult patients who underwent elective CABG, from March of 2015 to March of 2019. We assessed two groups of patients including the albumin (who received 50cc albumin 20% in priming solution) and the non-albumin groups. We recorded demographic data, medical history, and preoperative laboratory data. We compared postoperative changes in serum creatinine (Cr), blood urea nitrogen (BUN), and Glomerular Filtration Rate (GFR) up to 72 hours after surgery with preoperative ones. Also, the stage of kidney dysfunction was assessed according to the AKIN classification. The statistical analysis of the data was processed by SPSS 24 program.

Results

Overall, we reviewed 506 patients chart [260 (51.4%) in albumin and 246 (48.6%) in non-albumin group]. In both groups, serum Cr, BUN, and GFR increased in 72 hours postoperatively compared with preoperative levels. This increase was greater in the non-albumin group than in the albumin group. However, the difference was not statistically significant between the two groups (p > 0.05). None of the patients developed renal failure or required dialysis.

Conclusion

We concluded that the use of albumin in prime solution did not have a statistically significant effect on postoperative renal dysfunction after CABG.

Albumin use for fluid resuscitation in cardiac surgical patients: a survey of Canadian perioperative care providers

PURPOSE

To evaluate the perceptions and practices of Canadian cardiovascular anesthesiologists and intensivists towards intravenous albumin as a resuscitation fluid in patients undergoing cardiac surgery.

METHODS

We conducted a cross-sectional survey of cardiac anesthesiologists and intensivists involved in the care of cardiac surgical patients. The 22-item survey included seven open-ended questions and assessed practice patterns and attitudes towards albumin. Descriptive statistics were analyzed using counts and proportions. Qualitative data were analyzed to identify themes describing albumin use patterns in Canada.

RESULTS

A total of 133 respondents from seven provinces participated, with 83 (62%) using albumin perioperatively. The majority of respondents (77%) felt a low fluid balance in cardiac surgical patients was important, and that supplementing crystalloids with albumin was helpful for this objective (67%). There was poor agreement among survey respondents regarding the role of albumin for faster vasopressor weaning or intensive care discharge, and ≥ 90% did not feel albumin reduced mortality, renal injury, or coagulopathy. Nevertheless, cardiac surgical patients were identified as a distinct population where albumin may help to minimize fluid balance. There was an acknowledged paucity of formal evidence supporting possible benefits. Fewer than 10% of respondents could identify institutional or national guidelines for albumin use. A lack of evidence supporting albumin use in cardiac surgical patients, especially those at highest risk of complications, was a frequently identified concern.

CONCLUSIONS

The majority of Canadian anesthesiologists and intensivists (62%) use albumin in cardiac surgical patients. There is clinical equipoise regarding its utility, and an acknowledged need for higher quality evidence to guide practice.

Intravenous Fluid Administration and the Coagulation System

Intravenous fluid administration in veterinary patients can alter coagulation function by several mechanisms. Both crystalloid and colloid fluids cause hemodilution, reducing platelet count and plasma coagulation protein concentrations. Hemodilution is associated with a hypercoagulable effect at low dilutions and a hypocoagulable effect at higher dilutions. Composition of crystalloid fluids likely has a minor effect, primarily dependent on fluid ion composition. Hypertonic crystalloids may also cause hypocoagulability. Colloids, both synthetic and natural, can cause hypocoagulability by several mechanisms beyond the effects of hemodilution. These include impaired platelet function, decreased plasma coagulation factor activity, impaired fibrin formation and crosslinking, and accelerated fibrinolysis. The vast majority of the veterinary literature investigates the hypocoagulable effects of hydroxyethyl starch-containing fluids using in vitro, experimental, and clinical studies. However, results are inconsistent, likely due to the varying doses and physicochemical properties of the specific fluid products across studies. In addition, some evidence exists for hypocoagulable effects of gelatin and albumin solutions. There is also evidence that these colloids increase the risk of clinical bleeding in people. Limitations of the veterinary evidence for the hypocoagulable effects of colloid fluids include a predominance of in vitro studies and in vivo studies using healthy subjects, which exclude the interaction of the effects of illness. Therefore, clinical relevance of these effects, especially for low-molecular-weight hydroxyethyl starch, is unknown. Firm recommendations about the most appropriate fluid to use in clinical scenarios cannot be made, although it is prudent to limit the dose of synthetic colloid in at-risk patients. Clinicians should closely monitor relevant coagulation assays and for evidence of hemorrhage in at-risk patients receiving any type of fluid therapy, especially in large volumes.

Combined Use of Rotational Thromboelastometry (Rotem) and Platelet Impedance Aggregometry (Multiplate Analyzer) in Cyanotic and Acyanotic Infants and Children Undergoing Cardiac Surgery With Cardiopulmonary Bypass: Subgroup Analysis of a Randomized Clinical Trial

OBJECTIVES

Few studies have investigated the Multiplate platelet function analyzer in pediatrics. The authors evaluated Multiplate combined with Rotem in terms of guiding platelet transfusion after pediatric cardiac surgery with cardiopulmonary bypass (CPB). The authors further compared coagulation parameters between cyanotic and acyanotic patients.

DESIGN

Subgroup analysis of a randomized clinical trial.

SETTING

Tertiary hospital.

PARTICIPANTS

Patients weighing between seven and 15 kg.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Rotem and Multiplate tests were performed (1) after anesthesia induction, (2) upon CPB separation, and (3) upon intensive care unit arrival. Among a total of 59 subjects, 9 patients required platelet transfusion. In multivariate linear regression, analysis EXTEM maximum clot firmness upon CPB separation was associated with the volume of transfused platelets (regression coefficient = -0.348 [95% confidence interval -1.006 to -0.028]; p = 0.039). No such association was found for the Multiplate test. Acyanotic and cyanotic heart disease were present in 32 and 27 children, respectively. There were no significant differences between these two groups in terms of platelet count and function. Postoperative blood loss was significantly higher in the cyanotic group compared with the acyanotic arm (p = 0.015; difference [95% confidence interval -2.40 {-4.20 to -0.60}]). There were no differences between groups regarding transfusion of allogeneic blood products.

CONCLUSIONS

This study showed that Rotem, but not Multiplate results, were associated with platelet transfusion in pediatric cardiac surgery with no intake of platelet inhibitors. The usefulness of combining these tests in platelet transfusion decision-making needs to be evaluated in larger populations.

Perioperative fluid management for major elective surgery

BACKGROUND

Adequate fluid balance before, during and after surgery may reduce morbidity. This review examines current concepts surrounding fluid management in major elective surgery.

METHOD

A narrative review was undertaken following a PubMed search for English language reports published before July 2019 using the terms 'surgery', 'fluids', 'fluid therapy', 'colloids', 'crystalloids', 'albumin', 'starch', 'saline', 'gelatin' and 'goal directed therapy'. Additional reports were identified by examining the reference lists of selected articles.

RESULTS

Fluid therapy is a cornerstone of the haemodynamic management of patients undergoing major elective surgery. Both fluid overload and hypovolaemia are deleterious during the perioperative phase. Zero-balance fluid therapy should be aimed for. In high-risk patients, individualized haemodynamic management should be titrated through the use of goal-directed therapy. The optimal type of fluid to be administered during major surgery remains to be determined.

CONCLUSION

Perioperative fluid management is a key challenge during major surgery. Individualized volume optimization by means of goal-directed therapy is warranted during high-risk surgery. In most patients, balanced crystalloids are the first choice of fluids to be used in the operating theatre. Additional research on the optimal type of fluid for use during major surgery is needed.

Blood acid-base, haematological and haemostatic effects of hydroxyethyl starch (130/0.4) compared to succinylated gelatin colloid infusions in normovolaemic dogs

Synthetic colloids are commonly administered to dogs to treat absolute or relative hypovolaemia. Voluven^® (tetrastarch 130/0.4) and Gelofusine^® (succinylated gelatin) are available to veterinarians in South Africa. In humans, use of these products has caused acid–base derangements, changes in haematology and impaired haemostasis. We aimed to investigate these effects in healthy normovolaemic dogs. Eight healthy adult beagle dogs underwent a cross-over study, receiving Voluven^® or Gelofusine^® (10 mL/kg/h for 120 min) once each with a 14-day washout between treatments. Dogs were premedicated with dexmedetomidine (10 µg/kg intramuscularly). Anaesthesia was induced with propofol and the dogs were maintained with isoflurane-in-oxygen. The anaesthetised dogs were connected to a multi-parameter monitor to monitor physiological parameters throughout. Catheters placed in a jugular vein and dorsal metatarsal artery allowed sampling of venous and arterial blood. Blood was collected immediately prior to commencement of colloid infusion, after 60 min infusion and at the end of infusion (120 min) to allow for arterial blood gas analysis, haematology and coagulation testing (activated partial thromboplastin time [aPTT], prothrombin time [PT] and thromboelastography [TEG]). There was no effect, between treatments or over time, on blood pH. The haemoglobin concentration, erythrocyte count and haematocrit decreased significantly over time (all p < 0.01), with no differences between treatments, and remained within normal clinical ranges. There were no differences between treatments or over time for the TEG, aPTT and PT tests of haemostasis. At the dose studied, Voluven^® and Gelofusine^® had comparably negligible effects on blood acid–base balance and coagulation in normovolaemic dogs.

In Vitro Investigation of Hemocompatibility of Hydrothermally Treated Titanium and Titanium Alloy Surfaces

For decades, titanium and its alloys have been established as a biocompatible material for cardiovascular medical devices such as heart valves, stents, vascular grafts, catheters, etc. However, thrombosis is one of the reasons for implant failure, where blood clot forms on the implant surface, thus obstructing the flow of the blood and that leads to some serious complications. Various surface modification techniques such as heparin modification, albumin coating, surface anodization, plasma etching, and hydrothermal treatments have been explored to improve the hemocompatibility of titanium-based materials. However, there are several limitations related to the robustness of the surfaces and long-term efficacy in vivo. In this study, titanium and its alloy Ti-6Al-4V were hydrothermally treated to form nanostructured surfaces with the aim to enhance their hemocompatibility. These modified surfaces were characterized for their wettability, surface morphology, surface chemistry, and crystallinity. The hemocompatibility of these surfaces was characterized by evaluating blood plasma protein adsorption, platelet adhesion and activation, platelet-leukocyte complex formation, and whole blood clotting. The results indicate lower fibrinogen adsorption, cell adhesion, platelet activation, and whole blood clotting on hydrothermally treated surfaces. Thus, these surfaces may be a promising approach to prevent thrombosis for several titanium blood-contacting medical devices.

Cellulose/keratin–catechin nanocomposite hydrogel for wound hemostasis

Rapid wound hemostatic was achieved by a composite hydrogel based on human hair keratin–catechin nanoparticles and cellulose.

Effects of Tranexamic Acid Based on its Population Pharmacokinetics in Pediatric Patients Undergoing Distraction Osteogenesis for Craniosynostosis: Rotational Thromboelastometry (ROTEMTM) Analysis

Background: Distraction osteogenesis for craniosynostosis is associated with significant hemorrhage. Additionally, patients usually require several transfusions. Tranexamic acid (TXA) is effective for reducing blood loss and the need for transfusions during surgeries. However, the significance of TXA infusion has not been thoroughly described yet. Methods: Forty-eight children undergoing distraction osteogenesis for craniosynostosis were administered intraoperative TXA infusion (loading dose of 10 mg/kg for 15 min, followed by continuous infusion at 5 mg/kg/h throughout surgery; n = 23) or normal saline (control, n = 25). Rotational thromboelastometry (ROTEM^TM) was conducted to monitor changes in coagulation perioperatively. Results: Blood loss during surgery was significantly lower in the TXA-treated group than it was in the control group (81 vs. 116 mL/kg, P = 0.003). Furthermore, significantly fewer transfusions of red blood cells and fresh frozen plasma were required in the TXA group. In the control group, clotting time during the postoperative period was longer than it was during the preoperative period. Similarly, clot strength was weaker during the postoperative period. D-dimer levels dramatically increased in the control group compared with the TXA group after surgery. The duration of mechanical ventilation and the number of postoperative respiratory-related complications were significantly greater in the control group than they were in the TXA group. Conclusions: TXA infusion based on population pharmacokinetic analysis is effective in reducing blood loss and the need for transfusions during the surgical treatment of craniosynostosis. It can also prevent the increase in D-dimer levels without affecting systemic hemostasis.

Non-oncotic properties of albumin. A multidisciplinary vision about the implications for critically ill patients

INTRODUCTION

Effective resuscitation with human albumin solutions is achieved with less fluid than with crystalloid solutions. However, the role of albumin in today's critical care unit is also linked to its multiple pharmacological effects. Areas covered: The potential clinical benefits of albumin in select populations of critically ill patients like sepsis seem related to immunomodulatory and anti-inflammatory effects, antibiotic transportation and endothelial stabilization. Albumin transports many drugs used in critically ill patients. Such binding to albumin is frequently lessened in critically ill patients with hypoalbuminemia. These changes could result in sub-optimal treatment. Albumin has immunomodulatory capacity by binding several bacterial products. Albumin also influences vascular integrity, contributing to the maintenance of the normal capillary permeability. Moreover, the albumin molecule encompasses several antioxidant properties, thereby significantly reducing re-oxygenation injury, which is especially important in sepsis. In fact, most studies of albumin administration are a combination of a degree of resuscitation with a degree of maintenance or supplementation of albumin. Expert commentary: The potential clinical benefits of the use of albumin in selected critically ill patients such as sepsis seem related to its immunomodulatory and anti-inflammatory effects, antioxidant properties, antibiotic transportation and endothelial stabilization. Additional studies are warranted to further elucidate the underlying physiologic and molecular rationale.

Perioperative fluid management in major hepatic resection: an integrative review

BACKGROUND

Fluid intervention and vasoactive pharmacological support during hepatic resection depend on the preference of the attending clinician, institutional resources, and practice culture. Evidence-based recommendations to guide perioperative fluid management are currently limited. Therefore, we provide a contemporary clinical integrative overview of the fundamental principles underpinning fluid intervention and hemodynamic optimization for adult patients undergoing major hepatic resection.

DATA SOURCES

A literature review was performed of MEDLINE, EMBASE and the Cochrane Central Registry of Controlled Trials using the terms "surgery", "anesthesia", "starch", "hydroxyethyl starch derivatives", "albumin", "gelatin", "liver resection", "hepatic resection", "fluids", "fluid therapy", "crystalloid", "colloid", "saline", "plasma-Lyte", "plasmalyte", "hartmann's", "acetate", and "lactate". Search results for MEDLINE and EMBASE were additionally limited to studies on human populations that included adult age groups and publications in English.

RESULTS

A total of 113 articles were included after appropriate inclusion criteria screening. Perioperative fluid management as it relates to various anesthetic and surgical techniques is discussed.

CONCLUSIONS

Clinicians should have a fundamental understanding of the surgical phases of the resection, hemodynamic goals, and anesthesia challenges in attempts to individualize therapy to the patient's underlying pathophysiological condition. Therefore, an ideal approach for perioperative fluid therapy is always individualized. Planning and designing large-scale clinical trials are imperative to define the optimal type and amount of fluid for patients undergoing major hepatic resection. Further clinical trials evaluating different intraoperative goal-directed strategies are also eagerly awaited.

Haemostasis monitored in stored red blood cells, plasma and platelet concentrates in the proportion of 4 : 4 : 1 diluted with crystalloids and colloids

The aim of this in-vitro study was to evaluate haemostasis analysed with thromboelastometry and blood gas and blood count variables, in stored blood components and the effects after dilution with Ringer[Combining Acute Accent]s acetate, albumin and hydroxyethyl starch (HES). Aliquots from stored red blood cells, plasma and platelet concentrates were mixed in the proportion of 4 : 4 : 1 and analysed with rotational thromboelastometry (ROTEM), blood count [haemoglobin (Hb), haematocrit, platelet count] and blood gas (pH, calcium, sodium, potassium, glucose levels). The blood mix was thereafter diluted 20 and 33% with Ringer's acetate, albumin or HES. The stored blood component mix in a ratio of 4 : 4 : 1 had a low pH (7.11 ± 0.03, mean ± standard deviation), nonmeasurable calcium level, and high concentrations of sodium, potassium and glucose but ROTEM curves within normal range after recalcification. With Ringer's acetate dilution, the ROTEM variables changed almost linearly with increasing dilution volume. When albumin was used in the 33% dilution, the clot firmness of the fibrin clot (FibTEM) was further reduced, and with HES dilution, there was a pronounced impairment. The stored blood mix had a low pH and calcium level, both of which might have a significant influence on the coagulation process but normal ROTEM curves after recalcification. Dilution with Ringer's acetate and albumin resulted in moderate deterioration, while dilution with HES showed severely impaired haemostasis.

Perioperative coagulation assessment of patients undergoing major elective orthopedic surgery

Traditional coagulative parameters are of limited use in identifying perioperative coagulopathy occurring in patients undergoing major elective orthopedic surgery (MEOS). The aim of our study was to evaluate the coagulation changes in patients undergoing MEOS and to facilitate an early detection of perioperative coagulopathy in patients experiencing major intraoperative bleeding. We enrolled 40 consecutive patients (M/F 10/30, age range 34-90 years) who underwent MEOS at the Orthopedic Unit of the Padua University Hospital, Italy, between January 2014 and January 2015. Blood samples were obtained at the following time points: T0-pre: 30 min before surgery; T0-post: 30 min after the end of the procedure; T1: morning of the first postoperative day; T2: 7 ± 2 days after surgery. Patients who experienced an intraoperative blood loss ≥250 mL/h were considered as cases. Routine coagulative parameters, thromboelastometry and thrombin generation (TG) profiles were evaluated. At baseline, a significantly lower platelet count and FIBTEM MCF/AUC were observed in patents with excessive bleeding (p < 0.05 and 0.02/0.01, respectively). At T0-post and T1 intervals, cases showed hypocoagulation characterized by a significantly low platelet count (p = 0.001), prolonged CFT INTEM/EXTEM, reduction of alpha-angle and MaxV INTEM/EXTEM, MCF and AUC INTEM/EXTEM/FIBTEM (p < 0.05 in all comparisons). The only TG parameter standing out between study groups was time to peak at T0-pre. A low platelet count and fibrinogen activity were associated with significant intraoperative bleeding in patients undergoing MEOS. Thromboelastometry performed by ROTEM(®) identifies patients with coagulopathy.

Effect of perioperative crystalloid or colloid fluid therapy on hemorrhage, coagulation competence, and outcome: A systematic review and stratified meta-analysis

BACKGROUND

A meta-analysis concerning perioperative coagulation competence, hemorrhage, and outcome was conducted including the use of hydroxyethyl starches (HESs), dextran, or albumin versus administration of a crystalloid as control to assess the efficacy and safety of colloids and crystalloids for fluid administration during major elective surgery. Surgery was restricted to cardiovascular and noncardiovascular surgery, and HESs were stratified to HES 130/0.4 and HES 200/0.5.

METHODS

We searched Cochrane Central Register of Controlled Trials, MEDLINE, ISI Web of Science, EMBASE, conference proceedings, reference lists, and databases of ongoing trials.

RESULTS

Thirty one primary clinical randomized controlled trials included 2287 patients undergoing major surgery from January 2000 to August 2015. The perioperative changes in coagulation competence were measured by thromboelastography (TEG) maximum amplitude (MA) in 9 studies administering crystalloids versus HES and in 4 studies administering albumin versus HES. All studies but 1 disclosed increased reduction in TEG-MA following HES administration (P = 0.0001 and 0.0002). The total loss of blood was reported in 17 studies in which crystalloids were compared to HES and 12 studies reported increased blood loss after administration of HES (P < 0.003). When administering albumin versus HES, 6 studies reported reduced hemorrhage associated with albumin administration (P = 0.005). Reoperation was not significantly reduced by the use of crystalloids, but may be more frequent after HESs compared to albumin (P < 0.03). In this analysis, more patients admitted to administration of HESs were exposed to decrease coagulation competence, compared to perioperative crystalloids and albumin administration.

CONCLUSION

This stratified meta-analysis showed that increased blood loss was found in noncardiovascular surgery among patients receiving HES compared with crystalloids, followed by a marked reduction in TEG-MA, and infusion of 3rd-generation HES products did not influence the results significantly.

The Perioperative Use of Albumin

Human serum albumin (HSA) is the predominant product of hepatic protein synthesis and one of the more abundant plasma proteins. HSA is a monomeric multidomain macromolecule, representing the main determinant of plasma oncotic pressure and the main modulator of fluid distribution between body compartments. HSA displays an essential role in maintaining the integrity of the vascular barrier. HSA is the most important antioxidant capacity of human plasma, in addition to its ability to protect the body from the harmful effects of heavy metals such as iron and copper and reduce their ability to produce reactive oxygen radicals. HSA is the main depot for nitric oxide (NO) transport in the blood. HSA represents the main carrier for fatty acids, affects pharmacokinetics of many drugs, and provides the metabolic modification of some drugs and displays pseudo-enzymatic properties. HSA has been widely used successfully for more than 50 years in many settings of perioperative medicine including hypovolemia, shock, burns, surgical blood loss, sepsis, and acute respiratory distress syndrome (ARDS). Recently, the use of HSA has shown a promising neuroprotective effect in patients with subarachnoid hemorrhage. The most recent evidence-based functions and uses of HSA in the perioperative period are reviewed in this chapter.

Comparing the Effects of 5% Albumin and 6% Hydroxyethyl Starch 130/0.4 (Voluven) on Renal Function as Priming Solutions for Cardiopulmonary Bypass: A Randomized Double Blind Clinical Trial

Background:

The ideal strategy to prime the cardiopulmonary bypass (CPB) circuit in adult cardiac surgery is still a matter of debate.

Objectives:

In this retrospective study, we examined Albumin solution and hydroxyethyl starch (HES) for priming the CPB circuit and evaluated the differences in kidney function and bleeding and coagulation status in the two groups of patients.

Patients and Methods:

Sixty consecutive patients undergoing elective coronary artery bypass grafting were studied. Patients were excluded due to emergency surgery, history of cardiac surgery, history of receiving medication with antiplatelet agents except ASA 80 (mg/day) within the previous five days, preoperative coagulation disorder, left ventricular ejection fraction less than 50%, preoperative renal dysfunction (serum creatinine > 1.4 mg/dL), preoperative hepatic dysfunction (serum aspartate/alanine amino transferase > 60 U/l), preoperative electrolyte imbalance, known hypersensitivity to HES and chronic diuretic therapy. The patients were divided randomly into two groups of HES (n = 30) and Albumin (n = 30). Hemodynamic parameters, serum creatinine concentrations and glomerular filtration rate, PT, PTT and INR were measured. Early bleeding was measured according to the first 24-hour drainage from the tube. Hemodynamics and all laboratory measurements were performed after induction of anesthesia and at the morning of the first, second and third postoperative days in the ICU.

Results:

GFR differences were statistically lower in Albumin group in comparison with Group B at 24, 48 and 72 hours postoperation. Platelet count difference and postoperative bleeding were significantly lower in Albumin group.

Conclusions:

Administration of Albumin compared to HES in patients with a normal renal function results in a lower drop of GFR and platelet count, less bleeding and lower rise of serum creatinine.

The effect of tranexamic acid on blood coagulation in total hip replacement arthroplasty: rotational thromboelastographic (ROTEM®) analysis

We evaluated changes in rotational thromboelastometry (ROTEM(®) ) parameters and clinical outcomes in patients undergoing total hip replacement arthroplasty, with concomitant infusions of tranexamic acid and of 6% hydroxyethyl starch 130/0.4. Fifty-five patients were randomly assigned to either the tranexamic acid (n = 29) or the control (n = 26) group. Hydroxyethyl starch was administered in the range of 10-15 ml.kg(-1) during the operation in both groups. In the control group, the clot formation time and maximum clot firmness of APTEM showed significant differences when compared with those of EXTEM at one hour postoperatively, suggestive of fibrinolysis. In the tranexamic acid group, there was no significant difference between each postoperative EXTEM and APTEM parameter. In the tranexamic acid and control group, postoperative blood loss was 308 ml (210-420 [106-745]) and 488 ml (375-620 [170-910], p = 0.002), respectively, and total blood loss was 1168 ml (922-1470 [663-2107]) and 1563 ml (1276-1708 [887-1494], p = 0.003). Haemoglobin concentration was higher in the tranexamic acid group on the second postoperative day (10.5 (9.4-12.1 [7.9-14.0]) vs. 9.6 (8.9-10.5[7.3-16.0]) g.dl(-1) , p = 0.027). In patients undergoing total hip replacement arthroplasty, postoperative fibrinolysis aggravated by hydroxyethyl starch was attenuated by co-administration of 10 mg.kg(-1) tranexamic acid, which may have led to less postoperative blood loss.

Assessing the Methodology for Calculating Platelet Contribution to Clot Strength (Platelet Component) in Thromboelastometry and Thrombelastography

The viscoelastic properties of blood clot have been studied most commonly using thrombelastography (TEG) and thromboelastometry (ROTEM). ROTEM-based bleeding treatment algorithms recommend administering platelets to patients with low EXTEM clot strength (e.g., clot amplitude at 10 minutes [A10] <40 mm) once clot strength of the ROTEM® fibrin-based test (FIBTEM) is corrected. Algorithms based on TEG typically use a low value of maximum amplitude (e.g., <50 mm) as a trigger for administering platelets. However, this parameter reflects the contributions of various blood components to the clot, including platelets and fibrin/fibrinogen. The platelet component of clot strength may provide a more sensitive indication of platelet deficiency than clot amplitude from a whole blood TEG or ROTEM® assay. The platelet component of the formed clot is derived from the results of TEG/ROTEM® tests performed with and without platelet inhibition. In this article, we review the basis for why this calculation should be based on clot elasticity (e.g., the E parameter with TEG and the CE parameter with ROTEM®) as opposed to clot amplitude (e.g., the A parameter with TEG or ROTEM®). This is because clot elasticity, unlike clot amplitude, reflects the force with which the blood clot resists rotation within the device, and the relationship between clot amplitude (variable X) and clot elasticity (variable Y) is nonlinear. A specific increment of X (ΔX) will be associated with different increments of Y (ΔY), depending on the initial value of X. When calculated correctly, using clot elasticity data, the platelet component of the clot can provide a valuable insight into platelet deficiency in emergency bleeding.

Shock Management for Cardio-surgical ICU Patients - The Golden Hours

Postoperative shock following cardiac surgery is a serious condition with a high morbidity and mortality. There are four types of shock: cardiogenic, hypovolemic, obstructive and distributive and these can occur alone or in combination. Early identification of the underlying diseases and understanding of the mechanisms at play are key for successful management of shock. Prompt resuscitation measures are necessary to reverse the shock state and avoid permanent organ dysfunction or death. In this review, the authors focus on the management during the first 6 hours of shock (the 'golden hours'). They discuss how to optimise preload, vascular tone, contractility, heart rate and oxygen delivery. The review incorporates the findings of recent trials on early goal-directed therapy and includes practical recommendations in areas in which the evidence is scare or controversial. While the review focuses on cardio-surgical patients, the suggested treatment algorithms might be usefully expanded to other critically ill patients with shock arising from other causes.

Effects of different colloid infusions on ROTEM and Multiplate during elective brain tumour neurosurgery

Background

The European Medicines Agency does not recommend the use of hydroxyethyl starch-based volume replacement solutions in critically ill patients due to an increased risk of renal failure. However, this recommendation is questionable for its perioperative use. Several recent randomised controlled studies do not indicate a risk for renal failure—not even after high-risk surgery. Human albumin is used in our neurointensive care unit as a part of the “Lund concept” of brain injury resuscitation, and albumin has been introduced in elective neurosurgery instead of starch. The aim of our prospective unblinded observational cohort study was to compare the degree of dilutive coagulopathy after albumin and starch intra-operative fluid therapy.

Methods

Thirty-nine patients undergoing elective brain tumour surgery with craniotomy received either 130/0.42 hydroxyethyl starch or 5 % albumin infusions. The first 18 patients received starch, whereas the rest received albumin. Rotational thromboelastometry with ROTEM and platelet aggregometry with Multiplate were performed before surgery, after the first and second consecutive colloid infusions (250/500 ml albumin or 500/1000 ml starch) and at the end of surgery.

Results

Both intra- and inter-group comparisons showed more deranged ROTEM parameters after the higher doses of starch. Multiplate detected changes only in the albumin group after 500-ml infusion. Blood los did not differ between groups, nor did haemoglobin preoperatively or at end of surgery. Lower volumes of albumin were required to maintain stable intra-operative haemodynamic parameters; 250/500 ml albumin corresponded to 500/1000 ml starch.

Conclusions

Hydroxyethyl starch affected coagulation at lower volumes, with a more prominent effect on clot structure at the end of surgery, corroborating previous research. Only albumin decreased platelet aggregation, and 5 % albumin had a more potential volume effect than 130/0.42 hydroxyethyl starch.

The Effects of Haemodilution with Albumin on Coagulation in Vitro as Assessed by Rotational Thromboelastometry

We investigated the in vitro viscoelastic changes of progressive haemodilution with 4% albumin compared with normal saline (NS) using rotational thromboelastometry (ROTEM®, Pentapharm Co., Munich, Germany). Whole blood samples obtained from 20 healthy volunteers were diluted in vitro with 4% albumin or NS by 10%, 20% and 40%. Fibrinogen concentration and ROTEM® (EXTEM [screening test for the extrinsic haemostasis system], FIBTEM [EXTEM-based assay for the fibrin part of the clot]) variables including coagulation time, clot formation time (CFT), α-angle, maximum clot firmness and lysis index were measured in the undiluted sample and at each degree of haemodilution. There was no significant difference in fibrinogen concentration at equivalent haemodilutions with normal saline and 4% albumin solutions. Forty percent haemodilution with albumin significantly prolonged coagulation time (EXTEM P=0.007, FIBTEM P=0.0001) and significantly decreased lysis index (FIBTEM P=0.009) compared with NS. A significant decrease in maximum clot firmness from undiluted measurements ( P=0.05) was observed at lower haemodilutions with albumin (20% with EXTEM, 10% with FIBTEM) compared with NS (40% with EXTEM and FIBTEM). The adverse effects of large degrees of haemodilution with 4% albumin solution are in excess of what can be explained by haemodilution alone. This study suggests that large degrees of haemodilution with albumin impair fibrinogen activity to a greater extent than equivalent degrees of haemodilution with NS.

Massive transfusion and massive transfusion protocol

Haemorrhage remains a major cause of potentially preventable deaths. Rapid transfusion of large volumes of blood products is required in patients with haemorrhagic shock which may lead to a unique set of complications. Recently, protocol based management of these patients using massive transfusion protocol have shown improved outcomes. This section discusses in detail both management and complications of massive blood transfusion.

The impact of hydroxyethyl starches in cardiac surgery: a meta-analysis

Introduction

Recent studies in septic patients showed that adverse effects of hydroxyethyl starches (HESs) possibly outweigh their benefits in severely impaired physiological haemostasis. It remains unclear whether this also applies to patient populations that are less vulnerable. In this meta-analysis, we evaluated the impact of various HES generations on safety and efficacy endpoints in patients undergoing cardiac surgery.

Methods

We searched the PubMed, Embase and Cochrane Central Register of Controlled Trials databases for randomised controlled trials (RCTs) in the English or German language comparing the use of HES to any other colloid or crystalloid during open heart surgery.

Results

Blood loss and transfusion requirements were higher for older starches with mean molecular weights more than 200 kDa compared to other volume substitutes. In contrast, this effect was not observed with latest-generation tetrastarches (130/0.4), which performed even better when compared to albumin (blood loss of tetrastarch versus albumin: standardised mean difference (SMD), −0.34; 95% CI, −0.63, −0.05; P = 0.02; versus gelatin: SMD, −0.06; 95% CI, −0.20, 0.08; P = 0.39; versus crystalloids: SMD, −0.05; 95% CI, −0.20, 0.10; P = 0.54). Similar results were found for transfusion needs. Lengths of stay in the intensive care unit or hospital were significantly shorter with tetrastarches compared to gelatin (intensive care unit: SMD, −0.10; 95% CI, −0.15, −0.05; P = 0.0002) and crystalloids (hospital: SMD, −0.52; 95% CI, −0.90, −0.14; P = 0.007).

Conclusions

In this meta-analysis of RCTs, we could not identify safety issues with tetrastarches compared with other colloid or crystalloid solutions in terms of blood loss, transfusion requirements or hospital length of stay in patients undergoing cardiac surgery. The safety data on coagulation with older starches raise some issues that need to be addressed in future trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0656-0) contains supplementary material, which is available to authorized users.

Stroke volume-directed administration of hydroxyethyl starch (HES 130/0.4) and Ringer’s acetate in prone position during neurosurgery: a randomized controlled trial

PURPOSE

General anesthesia in the prone position is associated with hypotension. We studied stroke volume (SV)-directed administration of hydroxyethyl starch (HES 130 kDa/0.4) and Ringer’s acetate (RAC) in neurosurgical patients operated on in a prone position to determine the volumes required for stable hemodynamics and possible coagulatory effects.

METHODS

Thirty elective neurosurgical patients received either HES (n = 15) or RAC (n = 15). Before positioning, SV measured by arterial pressure waveform analysis was maximized by fluid boluses until SV did not increase more than 10 %. SV was maintained by repeated administration of fluid. RAC 3 ml/kg/h was infused in both groups. Thromboelastometry assessed coagulation. Mann–Whitney U test, Wilcoxon signed-rank test, ANOVA on ranks, and a linear mixed model were applied.

RESULTS

Comparable hemodynamics were achieved with the mean cumulative (SD) boluses of HES or RAC 240 (51) or 267 (62) ml (P = 0.207) before positioning, 340 (124) or 453 (160) ml (P = 0.039) 30 min after positioning, and 440 (229) or 653 (368) ml at the end of surgery (P = 0.067). The mean dose of basal RAC infusion was 813 (235) and 868 (354) ml (P = 0.620) in the HES and RAC group, respectively. Formation and maximum strength of the fibrin clot were decreased in the HES group. Intraoperative blood loss was comparable between groups (P = 0.861).

CONCLUSION

The amount of RAC needed in the prone position was 25 % greater. The cumulative dose of 440 ml HES induced a slight disturbance in fibrin formation and clot strength. We suggest cautious administration of HES during neurosurgery.

The use of balanced HES 130/0.42 during complex cardiac surgery; effect on blood coagulation and fluid balance: a randomized controlled trial

Introduction:

Colloids and crystalloid are used during cardiac surgery for priming of the cardiopulmonary bypass (CPB) circuit. Colloids may decrease postoperative fluid balance because of their high oncotic pressure and low risk of fluid extravasation. On the other hand, colloids have been shown to impair blood coagulation.

Materials and methods:

In a prospective, randomized, double-blinded study, 50 patients scheduled for coronary artery bypass grafting or a valve procedure were planned to be randomized to receive either balanced 6% HES130/0.42 or Ringer-acetate solution for CPB priming. Randomization was stopped prematurely after 35 randomized patients (19 in the HES and 16 in the Ringer groups) because of the published report where HES130/0.42 was associated with impaired renal function. Effects on haemostasis and fluid balance were investigated.

Results:

The rotational thromboelastometry (ROTEM®) parameters and chest tube drainage on the first postoperative morning (1POM) were comparable between the groups (p>0.05). However, patients in the HES group needed more blood and blood product transfusions. The total volume administered into the CPB circuit was lower in the HES than in the Ringer (RIN) group, 2905±1049 mL versus 3973±1207 mL (p=0.011), but there was no statistically significant difference in total fluid balance on the 1POM (5086±1660 mL in the HES group versus 5850±1514 mL in the RIN group, respectively).

Conclusions:

After complex cardiac surgery, the use of balanced 6% HES130/0.42 solution for CPB circuit priming did not impair haemostasis measured by ROTEM®, but it increased the need for transfusions. Fluid balance after CPB was less positive in the HES group, but, on the 1POM, it was comparable between the groups.

Albumin—Beyond Fluid Replacement in Cardiopulmonary Bypass Surgery

Maintaining vascular barrier competence, preventing interstitial edema, and keeping microcirculation intact is crucial to achieve an optimal outcome in cardiopulmonary bypass surgery (CPB). Blood contact with roller pumps and foreign surfaces during CPB induces shear stress and a pressure drop across the pump boot that leads to transient systemic activation of the inflammatory and hemostatic systems. Moreover, patients after CPB often need volume resuscitation using the smallest possible amount of colloid solution because of fluid overload. For this purpose, human-derived albumin may be preferred over synthetic colloids because CPB priming with albumin preserves oncotic pressure, prevents platelet adhesion, and likely induces less consumption of coagulation factors. In patients with increased bleeding or renal failure, albumin is a safe alternative because of its minimal side effects. Large, randomized clinical trials comparing the benefit of albumin versus other fluids are warranted in the future to define albumin’s distinct role in select high-risk surgical populations.

Impact of different types of resuscitation fluids on coagulation and continuous venovenous hemofiltration hemocompatibility in a porcine model

Intensive therapy demanding diseases (organ failure or sepsis) are assumed to be the etiology behind a decreased biocompatibility of extracorporeal systems for renal replacement therapy (RRT). There are also potential interactions between different components of the overall therapy. Volume substitutes are known to influence hemorheology and coagulation. To define a potential net effect of volume substitutes on the hemocompatibility of an RRT, we chose an animal model without interfering pathophysiologies. According to the problem of early filter failure and coagulation disorders in critically ill patients, we focused on the hypothesized interaction between RRT and different volume substitutes with respect to blood cell counts, coagulation parameters and required heparin dose. Forty-eight pigs were assigned to four groups of fluid therapy with either normal saline (NaCl), 6%HES130kD/0.4 (HES130), 6%HES200kD/0.5 (HES200) or 4%gelatin (GEL). Six pigs of each fluid group underwent continuous venovenous hemofiltration (CVVH), the remaining six served as the control group. Anticoagulation was performed with continuous heparin infusion. CVVH was run in a recirculation-mode for 4.5 h to force hemocompatibility reactions, thereafter in a standard-mode for 2 h. During the CVVH-treatment GEL reduced platelet counts and fibrinogen concentration and additionally lowered ATIII levels. Heparin requirements did not differ between different volume substitutes or CVVH and control groups. Severe pathophysiologies are not the only reason for a reduced hemocompatibility of CVVH treatment. Interaction of a particular volume substitute with CVVH should be considered when interpreting study results and evolving new strategies.

Stroke volume-directed administration of hydroxyethyl starch or Ringer's acetate in sitting position during craniotomy

BACKGROUND

To determine the volumes required for stable haemodynamics and possible effects on the coagulation, we studied stroke volume (SV)-directed administration of hydroxyethyl starch (HES 130 kDa/0.4) and Ringer's acetate (RAC) in neurosurgical patients operated on in a sitting position.

METHODS

Thirty craniotomy patients were randomised to receive either HES or RAC. Before positioning, SV, measured by arterial pressure waveform analysis, was maximised by boluses of fluid until SV did not increase more than 10%. SV was maintained by repeated administration of fluid. RAC 3 ml/kg/h was infused in both groups during surgery.

RESULTS

Comparable haemodynamics were achieved with the mean [standard deviation (SD)] cumulative doses of HES or RAC 271 (47) or 264 (50) ml (P = 0.699) before the sitting position. Mean (SD) doses of HES or RAC at 30 min after the positioning were 343 (94) or 450 (156) ml (P = 0.036), and at the end of surgery 464 (284) or 707 (425) ml, respectively (P = 0.087). The intraoperative fluid balance was more positive in the RAC than in the HES group [P = 0.044, 95% confidence interval (CI) -978 to -14]. Cardiac and stroke volume indexes [CI and stroke volume index (SVI)] increased in the HES group (P < 0.05) but not in the RAC group [non significant (N.S.)]. Neither coagulation profile nor blood loss differed between the groups.

CONCLUSION

Fluid filling with HES boluses resulted in a positive response in CI and SVI during the sitting position. The 34% smaller volume of HES than crystalloid and less positive fluid balance in the HES group might be important in craniotomy patients with decreased brain compliance.

Assessment of hemostatic changes after crystalloid and colloid fluid preloading in trauma patients using standard coagulation parameters and thromboelastography

Background:

The choice of an ideal fluid administered post trauma and its subsequent influence on coagulation still poses a clinical dilemma. Hence, this study was designed to assess the influence of in vivo hemodilution with various fluid preparations (4% gelatin, 6% hydoxyethyl starch (HES), Ringer's lactate, 0.9% normal saline) on coagulation using standard coagulation parameters and real-time thromboelastography (TEG) in patients undergoing elective surgery post trauma.

Methods:

In a randomized, double-blind study, 100 patients of either sex and age, belonging to ASA Grades I and II, scheduled for elective surgeries were allocated into four groups of 25 each according to the type of fluid infused. Group G (4% gelatin), Group N (0.9% normal saline), Group R (Ringer's lactate), and Group H (6% HES) received preloading with 1 L of fluid according to the group. The coagulation status of the patients was assessed during perioperative period (before surgery, after fluid preloading, and at the end of the surgery) using both conventional coagulation analysis and TEG.

Statistical Analysis:

Analysis of variance (ANOVA), post hoc and Pearson Chi-square test were used.

Results:

In all the patients preloaded with gelatin, there was a significant increase in prothrombin time index (PTI; 14.88±0.90 vs. 13.78±3.01, P<0.001) and international normalized ratio (INR; 1.12±0.09 vs. 1.09±0.19, P<0.05) compared to the baseline value. An increase was observed in these parameters in the postoperative period also. In the HES group, there was statistically significant increase in PT time (15.70±1.51 vs. 13.74±0.75, P=0.01) and INR (1.20±0.15 vs. 1.03±0.17, P<0.001) as compared to the baseline. In the intergroup comparisons, the patients preloaded with HES had a significant increase in INR (1.20±0.15 vs. 1.12±0.09, P=0.04) and reaction time (R time; 6.84±2.55 min vs. 4.79±1.77 min, P=0.02) as compared to the gelatin group. The fall in coagulation time (k time; 2.16±0.98 vs. 3.94±2.6, P=0.02), rise in maximum amplitude (MA; 61.94±14.08 vs. 50.11±14.10, P=0.04), and rise in A20 (56.17±14.66 vs. 43.11±14.24, P=0.05) were more in patients preloaded with RL as compared to the HES group. 100% patients in the gelatin group, 84.2% patients in the NS group, 94.4% patients in the RL group, and 66.7% patients in the HES group had hypocoagulable (R time > 14 min) state in the postoperative period.

Conclusion:

Crystalloids are optimal volume expanders in trauma, with RL having beneficial effects on coagulation system (decrease in k time and increase in MA and A20). Among the colloids, HES 6% (130/0.4) affects coagulation parameters (increase in PTI, INR, R time, k time) more than gelatin. Trial registration (protocol number-IEC/NP-189/2011).

Effect of rapid fluid resuscitation using crystalloids or colloids on hemostasis in piglets

BACKGROUND AND OBJECTIVES

Impairment of blood coagulation is one of the main side effects of volume replacement, particularly if artificial colloids such as hydroxyethyl starch (HES) and gelatine preparations are used. This animal study aimed to evaluate the effect of a single fast intravenous crystalloid or colloid fluid bolus on blood coagulation as measured by rotation thromboelastometry (ROTEM).

METHODS

Thirty-two anesthetized piglets were infused with a rapid 20 ml·kg(-1) fluid bolus of either normal saline (NS), 4% gelatine, 5% albumin or 6% HES 130/0.4 (n = 8 per group) over a period of 2 min. Hemostasis was assessed by ROTEM before and 1 min after fluid administration. Within-group differences were analyzed by Wilcoxon test, and additionally overall Kruskal-Wallis test followed by posthoc Mann-Whitney U-test were applied to detect differences between groups.

RESULTS

All fluids caused a significant weakening of clot strength within groups. HES and gelatine showed a significantly stronger impairment of clot growth and maximum clot firmness as compared with albumin and normal saline. Impairment of fibrin polymerization was more pronounced following HES as compared with all other fluids.

CONCLUSION

After moderate but very fast volume loading, HES and gelatine impair blood coagulation to a larger extent as compared with albumin or normal saline, while no significant differences were observed between both artificial colloids.

Colloids in the intensive care unit

PURPOSE

The most recent published evidence on the use of colloids versus crystalloids in critical care is reviewed, with a focus on population-dependent differences in safety and efficacy.

SUMMARY

Colloids offer a number of theoretical advantages over crystalloids for fluid resuscitation, but some colloids (e.g., hydroxyethyl starch solutions, dextrans) can have serious adverse effects, and albumin products entail higher costs. The results of the influential Saline Versus Albumin Fluid Evaluation (SAFE) trial and a subsequent SAFE subgroup analysis indicated that colloid therapy should not be used in patients with traumatic brain injury and other forms of trauma due to an increased mortality risk relative to crystalloid therapy. With regard to patients with severe sepsis, two meta-analyses published in 2011, which collectively evaluated 82 trials involving nearly 10,000 patients, indicated comparable outcomes with the use of either crystalloids or albumins. For patients requiring extracorporeal cardiopulmonary bypass (CPB) during heart surgery, the available evidence supports the use of a colloid, particularly albumin, for CPB circuit priming and postoperative volume expansion. In select patients with burn injury, the published evidence supports the use of supplemental colloids if adequate urine output cannot be maintained with a crystalloid-only rescue strategy.

CONCLUSION

The results of the SAFE trial and a subgroup analysis of SAFE data suggest that colloids should be avoided in patients with trauma and traumatic brain injury. There are minimal differences in outcome between crystalloids and hypo-oncotic or iso-oncotic albumin for fluid resuscitation in severe sepsis; in select populations, such as patients undergoing cardiac surgery, the use of iso-oncotic albumin may confer a survival advantage and should be considered a first-line alternative.

The effect of fibrinogen concentrate and factor XIII on thromboelastometry in 33% diluted blood with albumin, gelatine, hydroxyethyl starch or saline in vitro

BACKGROUND

Fluid replacement results in dilutional coagulopathy. We investigated the potential role of fibrinogen, factor XIII and a combination of both to reverse dilutional coagulopathy, assessed by thromboelastometry (ROTEM(®)).

MATERIAL AND METHODS

Blood samples from healthy volunteers were analysed undiluted and after 33% dilution in vitro with albumin, gelatine, 130/0.4 hydroxyethyl starch or saline. Diluted samples were incubated with fibrinogen (3 g/70 kg bodyweight equivalent), factor XIII (10,000 IU/70 kg bodyweight equivalent), or a combination of both. Measurements were performed using an extrinsic activated assay (EXTEM(®)) and a functional fibrin polymerisation test (FIBTEM(®)).

RESULTS

Compared with baseline, EXTEM clotting time increased with hydroxyethyl starch, exceeding the upper limit of the reference value. Albumin prolonged clotting time within normal limits. Gelatine did not change clotting time, and saline reduced clotting time. Clot formation time increased in colloids only. Maximum clot firmness of both EXTEM and FIBTEM decreased with all fluids, but was less pronounced in saline. Incubation with fibrinogen had no effect on EXTEM maximum clot firmness but improved FIBTEM maximum clot firmness in saline (P <0.001) and albumin (P <0.05), but not gelatine and hydroxyethyl starch). Factor XIII had no effect on any EXTEM and FIBTEM maximum clot firmness results. Fibrinogen and factor XIII combined did not improve EXTEM maximum clot firmness. Fibrinogen and factor XIII did not change FIBTEM maximum clot firmness in hydroxyethyl starch but improved FIBTEM maximum clot firmness in albumin (P <0.001), gelatine (P <0.01) and saline (P <0.001).

DISCUSSION

ROTEM parameters in dilutional coagulopathy in vitro cannot be improved with factor XIII alone in any tested diluent. The combination of fibrinogen and factor XIII is highly effective in raising FIBTEM maximum clot firmness after dilution with albumin, gelatine and saline back to normal values, but is ineffective in 130/0.4 hydroxyethyl starch.

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.

Evaluation of hemostatic changes using n thromboelastography after crystalloid or colloid fluid administration during major orthopedic surgery

The effects of Ringer lactate, 6% hydroxyethyl starch (130/0.4) or 4% succinylated gelatin solutions on perioperative coagulability were measured by thromboelastography (TEG). Seventy-five patients (ASA I-III) who were to undergo major orthopedic procedures performed under epidural anesthesia were included in the study. Patients were randomly divided into three groups of 25 each for the administration of maintenance fluids: group RL (Ringer lactate), group HES (6% hydroxyethyl starch 130/0.4), and group JEL (4% gelofusine solution). Blood samples were obtained during the perioperative period before epidural anesthesia (t1, baseline), at the end of the surgery (t2), and 24 h after the operation (t3). TEG data, reaction time (R), coagulation time (K), angle value (α), and maximum amplitude (MA) were recorded. TEG parameters changed from normal values in all patients. In group RL, R and K times decreased compared to perioperative values while the α angle and MA increased (P < 0.05). In group HES, R and K times increased, however, the α angle and MA decreased (P < 0.05). In group JEL, R time increased (P < 0.05), but K time, α angle and MA did not change significantly. In the present study, RL, 6% HES (130/0.4) and 4% JEL solutions caused changes in the coagulation system of all patients as measured by TEG, but these changes remained within normal limits.

Thromboelastometry during intraoperative transfusion of fresh frozen plasma in pediatric neurosurgery

Normal blood coagulation is essential in pediatric neurosurgery because of the risk of abundant bleeding, and therefore it is important to avoid transfusion of fluids that might interfere negatively with the coagulation process. There is a lack of transfusion guidelines in massive bleeding with pediatric neurosurgical patients, and early use of blood compounds is partly controversial. We describe two pediatric patients for whom fresh frozen plasma (FFP) infusion was started at the early phase of brain tumor surgery to prevent intraoperative coagulopathy and hypovolemia. In addition to the traditional laboratory testing, modified thromboelastometry analyses were used to detect possible disturbances in coagulation. Early transfusion of FFP and red blood cells preserved the whole blood coagulation capacity. Even with continuous FFP infusion, fibrin clot firmness was near to critical value at the end of surgery despite increased preoperative values. By using FFP instead of large amounts of crystalloids and colloids when major blood loss is expected, blood coagulation is probably less likely to be impaired. Our results indicate, however, that the capacity of FFP to correct fibrinogen deficit is limited.

Benefits and Risks of Using Gelatin Solution as a Plasma Expander for Perioperative and Critically Ill Patients: A Meta-Analysis

This meta-analysis aimed to evaluate the benefits and risks of gelatin solutions compared to other intravenous fluids for patients in perioperative and critical care settings. Of the 66 studies identified from MEDLINE and EMBASE databases, 30 randomised controlled trials involving 2709 patients met the inclusion criteria and were subject to meta-analysis. The risk of mortality (odds ratio 1.03, 95% confidence interval 0.80 to 1.32) and amount of blood loss (weighted-mean-difference 7.56 ml, 95% confidence interval 18.75 to 33.87) were not significantly different between patients who were treated with gelatin solutions and other types of intravenous fluids. When compared to starches, gelatin solutions were associated with a lower risk of acute renal failure (odds ratio 0.43, 95% confidence interval 0.20 to 0.92; P=0.03). When gelatin solutions were compared to isotonic albumin, patients who were treated with gelatin solutions required a small, but significantly greater amount of blood transfusion (weighted-mean-difference 180 ml, 95% confidence interval 8.1 to 353.6; P=0.04). These findings suggest that using gelatin solutions is associated with a lower risk of acute renal failure compared to older starches. Using gelatin as a plasma expander appears to have no significant advantages over crystalloids or isotonic albumin on mortality and may have a slightly higher risk of requiring allogeneic blood transfusion in perioperative and critically ill patients. An adequately powered randomised controlled trial with economic analysis is needed before gelatin solution can be recommended as a routine plasma expander for patients undergoing major surgery or who are critically ill.

Influence of hydroxyethyl starch (HES) 130/0.4 on hemostasis as measured by viscoelastic device analysis: a systematic review

PURPOSE

Hydroxyethyl starch solutions (HES) are plasma volume expanders which affect hemostasis. Newer HES 130/0.4 is said to be safer. Reevaluation of published evidence is necessary after the recent retraction of studies.

METHODS

Systematic review of studies assessing HES 130/0.4 effects on hemostasis by thrombelastography (TEG, ROTEM) or Sonoclot (SCR) in comparison with crystalloid or albumin control fluids was performed. Only studies which provided statistical comparisons between study fluids were analyzed. Studies were divided into in vitro or in vivo hemodilution studies. We assessed study quality, HES effects which differed significantly from controls, values outside normal range, degree of hemodilution, and cumulative HES dose.

RESULTS

Seventeen in vitro and seven in vivo hemodilution studies were analyzed. Four studies reported quality control measures. Nineteen studies (all 15 ROTEM studies, 3 of 5 in vitro TEG, and 1 of 2 SCR studies) showed a significant hypocoagulatory effect of HES 130/0.4 on clot formation, while clotting time was not uniformly affected. Three in vivo TEG studies with low HES doses or cancer patients found mixed or nonsignificant results. In studies which provided normal ranges (n = 9), more values were outside normal ranges in the HES than in the control groups (87/122 vs. 58/122, p < 0.001). Dose effects were apparent in the in vitro studies, which investigated higher dilutions up to 80%. In vivo studies were fewer and did not investigate doses >40 ml/kg.

CONCLUSIONS

HES 130/0.4 administration results in a weaker and smaller clot. Until results from well-designed clinical trials are available, safer fluids should be chosen for patients with impaired coagulation.

Hydroxyethyl starches and dextran during hip replacement surgery: effects on blood volume and coagulation

BACKGROUND

Colloid fluids influence the coagulation system by diluting the plasma and, potentially, by exerting other effects that are unique for each fluid product. We hypothesised that changes in the coagulation measured at the end of surgery would be mainly governed by differences in half-life between the colloid fluids.

METHODS

Eighty-four patients were randomised to receive one of four colloids: HES 130/0.42/6:1 (Venofundin(®)), 130/0.4/9:1 (Voluven(®)), 200/0.5/5:1 (Haes-steril(®)) and 6% dextran 70 (Macrodex(®)). Blood samples were taken just before and after a preoperative 500 ml bolus, and also after subsequent elective hip replacement surgery. Volume expansion was estimated from the blood dilution and coagulation assessed by ROTEM, activated partial thromboplastin time, prothrombin international normalised ratio (PT-INR), D-dimer and thrombin-antithrombin complex (TAT).

RESULTS

The blood volume expansion amounted to approximately 600 ml for all four colloids directly after infusion. Voluven(®) and Haes-steril(®) prolonged the aPT time and Venofundin(®) increased TAT. Although all colloids increased PT-INR and D-dimer, the ROTEM analyses showed that they consistently shortened the clotting time and weakened the clot strength. These effects were mainly unchanged after surgery, during which the haemorrhage averaged 500-600 ml. Macrodex(®) produced a stronger volume support at the end of the surgery (91% of infused volume; P<0.001) than the three starch solutions (42-60%).

CONCLUSIONS

All tested colloid fluids induced a mild hypercoagulable state with faster clotting, but with weaker clot strength. The additive influence of surgery was relatively small, and postoperative changes in coagulation were mainly due to differences in the half-life of each colloid.