Use of modified fluid gelatin and hydroxyethyl starch for colloidal volume replacement in major orthopaedic surgery

Incidence and risk factors of postoperative hyperamylasemia and pancreatitis following total knee arthroplasty: a retrospective study

BACKGROUND

Postoperative hyperamylasemia and pancreatitis are recognized complications after abdominal and spinal surgeries. The aim of this study is to investigate the incidence and identify risk factors for postoperative hyperamylasemia and pancreatitis following total knee arthroplasty.

METHODS

170 patients undergoing total knee arthroplasty were retrospectively identified from our database from January 2017 to January 2021. Patients were divided into normal and hyperamylasemia groups based on the presence of serum amylase level within or greater than the normal range. The diagnosis of postoperative pancreatitis was based on the 2012 revised Atlanta Classification of Acute Pancreatitis. Patient demographics, perioperative parameters were investigated with student t test, chi square test and multivariate logistic regression analysis.

RESULTS

43 patients (25.3%) exhibited postoperative hyperamylasemia while eight patients (4.7%) exhibited serum amylase < 5 times the normal upper limit. One patient (0.6%) was designated as having postoperative pancreatitis. More patients with Hypertriglyceridemia (HTG) were noted in hyperamylasemia group (P = 0.009) compared with normal group. Hyperamylasemia group showed higher preoperative serum amylase (74.95 vs. 55.62 IU/L, P < 0.001), higher intra-operative blood loss (IBL) (117.67 vs. 77.01 mL, P = 0.040) and longer surgical duration (132.98 vs. 107.01 min, P = 0.041). Multivariate logistic analysis revealed that HTG (OR = 0.189, P = 0.006), preoperative serum amylase (OR = 1.042, P < 0.001) and IBL (OR = 1.004, P = 0.022) were independent risk factors for postoperative hyperamylasemia.

CONCLUSIONS

A significant percentage of patients developed hyperamylasemia after total knee arthroplasty. Patients with HTG, higher preoperative serum amylase and higher IBL had an increased risk of developing postoperative hyperamylasemia and pancreatitis.

Acute Kidney Injury and Renal Replacement Therapy: A Review and Update for the Perioperative Physician

Post-operative acute kidney injury is a devastating complication with significant morbidity and mortality associated with it. The perioperative anesthesiologist is in a unique position to potentially mitigate the risk of postoperative AKI, however, understanding the pathophysiology, risk factors and preventative strategies is paramount. There are also certain clinical scenarios, where renal replacement therapy may be indicated intraoperatively including severe electrolyte abnormalities, metabolic acidosis and massive volume overload. A multidisciplinary approach including the nephrologist, critical care physician, surgeon and anesthesiologist is necessary to determine the optimal management of these critically ill patients.

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.

Fluid resuscitation-related coagulation impairment in a porcine hemorrhagic shock model

Background

Fast and effective treatment of hemorrhagic shock is one of the most important preclinical trauma care tasks e.g., in combat casualties in avoiding severe end-organ damage or death. In scenarios without immediate availability of blood products, alternate regimens of fluid resuscitation represent the only possibility of maintaining sufficient circulation and regaining adequate end-organ oxygen supply. However, the fluid choice alone may affect the extent of the bleeding by interfering with coagulation pathways. This study investigates the impact of hydroxyethyl starch (HES), gelatine-polysuccinate (GP) and balanced electrolyte solution (BES) as commonly used agents for fluid resuscitation on coagulation using a porcine hemorrhagic shock model.

Methods

Following approval by the State and Institutional Animal Care Committee, life-threatening hemorrhagic shock was induced via arterial blood withdrawal in 24 anesthetized pigs. Isovolumetric fluid resuscitation with either HES, GP or BES (n = 3 × 8) was performed to compensate for the blood loss. Over four hours, hemodynamics, laboratory parameters and rotational thromboelastometry-derived coagulation were analyzed. As secondary endpoint the porcine values were compared to human blood.

Results

All the agents used for fluid resuscitation significantly affected coagulation. We measured a restriction of laboratory parameters, clot development and clot firmness, particularly in HES- and GP-treated animals. Hemoglobin content dropped in all groups but showed a more pronounced decline in colloid-treated pigs. This effect was not maintained over the four-hour monitoring period.

Conclusion

HES, GP, and BEL sufficiently stabilized the macrocirculation, but significantly affected coagulation. These effects were most pronounced after colloid and particularly HES administration. Despite suitability for rapid hemodynamic stabilization, colloids have to be chosen with caution, because their molecular properties may affect coagulation directly and as a consequence of pronounced hemodilution. Our comparison of porcine and human coagulation showed increased coagulation activity in pig blood.

Effect of gelatin-polysuccinat on cerebral oxygenation and microcirculation in a porcine haemorrhagic shock model

BACKGROUND

During early treatment of haemorrhagic shock maintenance of cerebral and end-organ oxygen supply by fluid resuscitation is mandatory. Gelatin-polysuccinat (GP) recently regained attention despite a still unclear risk profile and widely unknown effects on cerebral and peripheral microcirculation. This study investigates the effects of GP versus balanced electrolyte solution (BEL) with focus on cerebral regional oxygen saturation and peripheral microcirculation in a porcine haemorrhagic shock model.

METHODS

After Animal Care Committee approval haemorrhagic shock was induced by arterial blood withdrawal in 27 anaesthetized pigs. Consequently, the animals received rapid fluid resuscitation by either GP or BEL to replace the removed amount of blood, or remained untreated (n = 3 × 9). Over two hours cerebral regional oxygen saturation by near-infrared spectroscopy and peripheral buccal microcirculation by combined white-light spectrometry and laser-Doppler flowmetry were recorded. Secondary parameters included extended haemodynamics, spirometry, haematological and blood gas parameters.

RESULTS

Both fluid resuscitation regimes sufficiently stabilized the macro- and microcirculation in haemorrhagic shock with a more pronounced effect following GP infusion. GP administration led to a persisting, critical impairment of cerebral regional oxygen saturation through considerable haemodilution. Survival rates were 100% in both fluid resuscitation groups, but only 33% in the untreated control.

CONCLUSION

Equal amounts of GP and BEL sufficiently stabilize systemic circulation and microcirculatory perfusion. Forced fluid resuscitation by GP should be applied with caution to prevent haemodilution-induced impairment of cerebral oxygen delivery.

Prevention of Acute Renal Failure - Fluid Repletion and Colloids

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

Prevention of acute kidney injury and protection of renal function in the intensive care unit: update 2017 : Expert opinion of the Working Group on Prevention, AKI section, European Society of Intensive Care Medicine

BACKGROUND

Acute kidney injury (AKI) in the intensive care unit is associated with significant mortality and morbidity.

OBJECTIVES

To determine and update previous recommendations for the prevention of AKI, specifically the role of fluids, diuretics, inotropes, vasopressors/vasodilators, hormonal and nutritional interventions, sedatives, statins, remote ischaemic preconditioning and care bundles.

METHOD

A systematic search of the literature was performed for studies published between 1966 and March 2017 using these potential protective strategies in adult patients at risk of AKI. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, exposure to potentially nephrotoxic drugs and radiocontrast. Clinical endpoints included incidence or grade of AKI, the need for renal replacement therapy and mortality. Studies were graded according to the international GRADE system.

RESULTS

We formulated 12 recommendations, 13 suggestions and seven best practice statements. The few strong recommendations with high-level evidence are mostly against the intervention in question (starches, low-dose dopamine, statins in cardiac surgery). Strong recommendations with lower-level evidence include controlled fluid resuscitation with crystalloids, avoiding fluid overload, titration of norepinephrine to a target MAP of 65-70 mmHg (unless chronic hypertension) and not using diuretics or levosimendan for kidney protection solely.

CONCLUSION

The results of recent randomised controlled trials have allowed the formulation of new recommendations and/or increase the strength of previous recommendations. On the other hand, in many domains the available evidence remains insufficient, resulting from the limited quality of the clinical trials and the poor reporting of kidney outcomes.

Prevention of post-traumatic clinical capillary leak syndrome

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

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

Hydroxyeyhyl starch: Controversies revisited

Hydroxyethyl starch (HES) family has been one of the cornerstones in fluid management for over four decades. Recent evidence from clinical studies and meta-analyses has raised few concerns about the safety of these fluids, especially in certain subpopulations of patients. High-quality clinical trials and meta-analyses have emphasized nephrotoxic effects, increased risk of bleeding, and a trend toward higher mortality in these patients after the use of HES solutions. Scientific evidence was derived from international guidelines, aggregated research literature, and opinion-based evidence was obtained from surveys and other activities (e.g., internet postings). On critical analysis of the current data available, it can be summarized that further large scale trials are still indicated before HES can be discarded.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Colloid solutions for fluid resuscitation

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Colloid solutions for fluid resuscitation

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

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.

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.

Prevention of acute kidney injury and protection of renal function in the intensive care unit. Expert opinion of the Working Group for Nephrology, ESICM

BACKGROUND

Acute renal failure on the intensive care unit is associated with significant mortality and morbidity.

OBJECTIVES

To determine recommendations for the prevention of acute kidney injury (AKI), focusing on the role of potential preventative maneuvers including volume expansion, diuretics, use of inotropes, vasopressors/vasodilators, hormonal interventions, nutrition, and extracorporeal techniques.

METHOD

A systematic search of the literature was performed for studies using these potential protective agents in adult patients at risk for acute renal failure/kidney injury between 1966 and 2009. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, and use of potentially nephrotoxic drugs and radiocontrast media. Where possible the following endpoints were extracted: creatinine clearance, glomerular filtration rate, increase in serum creatinine, urine output, and markers of tubular injury. Clinical endpoints included the need for renal replacement therapy, length of stay, and mortality. Studies are graded according to the international Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) group system.

CONCLUSIONS AND RECOMMENDATIONS

Several measures are recommended, though none carries grade 1A. We recommend prompt resuscitation of the circulation with special attention to providing adequate hydration whilst avoiding high-molecular-weight hydroxy-ethyl starch (HES) preparations, maintaining adequate blood pressure using vasopressors in vasodilatory shock. We suggest specific vasodilators [corrected] under strict hemodynamic control, sodium bicarbonate for emergency procedures administering contrast media, and periprocedural hemofiltration in severe chronic renal insufficiency undergoing coronary intervention.

ELECTRONIC SUPPLEMENTARY MATERIAL

The online version of this article (doi:10.1007/s00134-009-1678-y) contains supplementary material, which is available to authorized users.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Role of fibrinogen-, factor VIII- and XIII-mediated clot propagation in gelatin haemodilution

BACKGROUND

Gelatin solution impairs coagulation. The mechanism of coagulopathy is incompletely defined. The purpose of this study was to evaluate the capacity of single coagulation factors to reverse gelatin-promoted whole-blood coagulation disorders in vitro.

METHODS

Venous blood was withdrawn from 12 volunteers in a crossover study. Four percent succinylated gelatin was added to citrated whole-blood samples to make a 40 vol% end-concentration of gelatin. The baseline and 40 vol% samples, and samples with addition of fresh-frozen plasma (FFP), fibrinogen, coagulation factors XIII (FXIII) or VIII, together with the von Willebrand factor (FVIII+vWF), were analysed by thromboelastometry (ROTEM. Coagulation was initiated by tissue thromboplastin (ExTEM with and without cytochalasin to determine the functional component of fibrinogen (FibTEM.

RESULTS

Initiation of coagulation and fibrin formation were delayed at 40 vol% gelatin dilution. At this stage, the median (25th-75th percentiles) maximum clot firmness (MCF) was 76.3 (65.9-80.0) and 32.5 (27.4-45.0)% of the pre-dilution value in ExTEM and FibTEM thromboelastometry, respectively. Coagulation time was corrected by addition of fibrinogen and FFP in ExTEM and FibTEM analysis, whereas FVIII or FXIII had minimal effects. MCF was partly restored only by FFP in ExTEM. In FibTEM analysis, MCF improved more by fibrinogen than by FVIII+VWF, FXIII or FFP.

CONCLUSIONS

Gelatin-induced whole-blood coagulation disorder in vitro is mainly dependent on the initial fibrinogen-fibrin interaction. The proposed mechanism might suggest not to reverse gelatin coagulopathy solely by fibrinogen administration. The administration of FFP, a mixture of different coagulation factors, reversed the gelatin-induced in vitro coagulopathy the best.

Effects of a predominantly hydroxyethyl starch (HES)-based and a predominantly non HES-based fluid therapy on renal function in surgical ICU patients

PURPOSE

To compare the effects of predominantly hydroxyethyl starch (HES 6% 130/0.4)-based with predominantly gelatin 4%-based fluid therapy on renal function in surgical intensive care unit (ICU) patients.

METHODS

Before-after, retrospective, study of surgical ICU patients. All patients admitted from January to June 2005 formed the HES group, with HES 130/0.4 as the standard colloid of choice. All patients admitted from January to June 2006 formed the GEL group, with gelatin 4% as the primary colloid. Acute renal failure (ARF) was defined as new need for renal replacement therapy (RRT) or at least a two-fold increase in baseline creatinine.

RESULTS

There were 1383 patients in the HES group and 1528 in the GEL group; 118 and 87, in each group respectively, had severe sepsis. The incidence of ARF and ICU and hospital mortality rates were similar in the two groups. In a post-hoc multivariable analysis, cumulative doses >33 ml/kg of either HES (OR = 1.85, 95% CI: 1.01-3.41, p < 0.001) or gelatin (OR = 1.99, 95% CI: 1.05-3.79, p = 0.035) were associated with a higher risk of ARF.

CONCLUSIONS

The incidence of ARF was similar in patients who received predominantly HES (6% 130/.04) fluid therapy and in those who received predominantly gelatin 4%. Moderate cumulative doses of modern HES or gelatin solutions may be associated with a higher risk of ARF.

Colloid solutions for fluid resuscitation

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Intensive insulin therapy and pentastarch resuscitation in severe sepsis

BACKGROUND

The role of intensive insulin therapy in patients with severe sepsis is uncertain. Fluid resuscitation improves survival among patients with septic shock, but evidence is lacking to support the choice of either crystalloids or colloids.

METHODS

In a multicenter, two-by-two factorial trial, we randomly assigned patients with severe sepsis to receive either intensive insulin therapy to maintain euglycemia or conventional insulin therapy and either 10% pentastarch, a low-molecular-weight hydroxyethyl starch (HES 200/0.5), or modified Ringer's lactate for fluid resuscitation. The rate of death at 28 days and the mean score for organ failure were coprimary end points.

RESULTS

The trial was stopped early for safety reasons. Among 537 patients who could be evaluated, the mean morning blood glucose level was lower in the intensive-therapy group (112 mg per deciliter [6.2 mmol per liter]) than in the conventional-therapy group (151 mg per deciliter [8.4 mmol per liter], P<0.001). However, at 28 days, there was no significant difference between the two groups in the rate of death or the mean score for organ failure. The rate of severe hypoglycemia (glucose level, < or = 40 mg per deciliter [2.2 mmol per liter]) was higher in the intensive-therapy group than in the conventional-therapy group (17.0% vs. 4.1%, P<0.001), as was the rate of serious adverse events (10.9% vs. 5.2%, P=0.01). HES therapy was associated with higher rates of acute renal failure and renal-replacement therapy than was Ringer's lactate.

CONCLUSIONS

The use of intensive insulin therapy placed critically ill patients with sepsis at increased risk for serious adverse events related to hypoglycemia. As used in this study, HES was harmful, and its toxicity increased with accumulating doses. (ClinicalTrials.gov number, NCT00135473.)

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

We investigated the effect of postoperative administration of colloids on hemostasis in 45 patients after cardiac surgery. Patients were randomized to receive 15 mL kg(-1) of either 4% albumin, 4% succinylated gelatin, or 6% hydroxyethyl starch (molecular weight of 200 kDa/degree of substitution 0.5) as a short-term infusion. There was a comparable decrease in maximum clot firmness of thromboelastometry tracings in gelatin and hydroxyethyl starch groups immediately after completion of the infusion, whereas these values remained unchanged in the albumin group. The impairment in clot strength persisted up to 2 h, although the values partly recovered. Postoperative bleeding correlated inversely with the clot strength in pooled data of the artificial colloids. Fibrin formation (clot formation time, alpha-angle) and fibrinogen-dependent clot strength (maximum clot firmness and shear elastic modulus) were more disturbed in the hydroxyethyl starch group than in the gelatin group. We conclude that after cardiopulmonary bypass surgery, both gelatin and hydroxyethyl starch impair clot strength and fibrin buildup, which may predispose patients to increased blood loss. The greatest impairment in hemostasis was seen after hydroxyethyl starch administration, whereas albumin appeared to have the least effect on hemostatic variables.

Artificial colloids impair haemostasis. An in vitro study using thromboelastometry coagulation analysis

BACKGROUND

Hydroxyethyl starch (HES) solutions impair haemostatic mechanisms. The impact of the degree of substitution (DS) of a HES solution on thromboelastometry tracings is unclear. Therefore we tested the hypothesis of whether the DS has an effect on the haemostatic defect caused by HES, and assessed whole blood coagulation by thromboelastometry coagulation analysis (ROTEM, Pentapharm Co., Munich, Germany) in serial in vitro haemodilutions of colloids.

METHODS

Whole blood was withdrawn from 12 volunteers in a crossover study. Six per cent low-molecular weight HES with a high (HES MW 120 kDa/degree of substitution 0.7) and low (HES MW 130 kDa/0.4) degree of substitution, 4% succinylated gelatin (GEL) or 4% albumin (ALB) was added to citrated venous whole blood samples to make 20, 40, 60 vol.% end-concentrations of each of the solutions. Samples were analyzed by ROTEM.

RESULTS

There was a comparable decrease in maximum clot firmness (MCF) and shear elastic modulus [G = 5000 x MCF/(100-MCF)] by HES 120/0.7 and HES 130/0.4 at 20 and 40 vol.% dilutions. At 60 vol.% dilution HES 120/0.7 decreased less alpha-angle and MCF than HES 130/0.4 (P < 0.05). With moderate dilutions all colloids shortened coagulation time (CT). At 20, 40 and 60 vol.% dilutions MCF and G were more decreased in both HES groups than in the ALB and GEL groups (P < 0.05). Furthermore, at 40 and 60 vol.% dilutions G deteriorated more in the GEL than in the ALB group (P < 0.05).

CONCLUSION

In vitro the impact of the degree of substitution of HES solution on thromboelastometry coagulation analysis was modest. Haemodilution with gelatin and albumin induced fewer coagulation abnormalities than HES. In addition, the haemodilution with gelatin impaired coagulation more than albumin solution.

A randomized, controlled study of fluid management in infants and toddlers during surgery: hydroxyethyl starch 6% (HES 70/0.5) vs lactated Ringer's solution

BACKGROUND

Volume replacement with hydroxyethyl starch (HES), a synthetic colloid, is widely accepted in adults, but only few data exist regarding its use in children. The aim of this study was to assess the effect of a low molecular weight HES solution (HES 70/0.5) compared with lactated Ringer's solution (LR) on haemoglobin levels as an indirect measure of plasma expansion in infants and toddlers, and its perioperative safety.

METHODS

Sixty-four patients, aged 1-38 months, were allocated randomly to receive 20 ml x kg-1 body weight of either HES 70/0.5 or LR during the first hour of urological surgery lasting >2 h. Thereafter, only LR was infused to maintain haemodynamic stability. Intraoperative blood loss and administered fluid volumes were analysed. Haemoglobin levels were determined perioperatively and intraoperatively at completion of volume loading. Changes in body weight and the incidence of postoperative oedema were assessed 24 and 48 h after surgery. For the safety analysis, patients were monitored for 72 h.

RESULTS

Intraoperative haemoglobin levels decreased significantly more with HES 70/0.5 (30 +/- 10 g.l-1) compared with LR (21 +/- 12 g.l-1) (P < 0.01). The overall administered fluid volumes during surgery did not differ between groups. The postoperative changes in body weight and incidence of postoperative oedema did not differ between groups. No anaphylactoid reactions, pruritus or adverse effects were observed during the study period.

CONCLUSIONS

A larger decrease in haemoglobin levels in infants and toddlers after HES 70/0.5 (20 ml.kg-1) compared with LR indicates a more effective plasma expansion. HES might be considered as a volume expander in the paediatric population.

Salt of the earth or a drop in the ocean? A pathophysiological approach to fluid resuscitation

The evolved endocrine response after injury leads to sodium, chloride, and water retention at a time when large volumes of sodium containing fluids are given to maintain the circulation and preserve tissue oxygenation. Sodium, chloride, and water are also retained because of increased systemic vascular permeability to plasma proteins, especially albumin, which sequesters fluid in the interstitial space and causes oedema. Excessive fluid and electrolyte retention and interstitial oedema are associated with the systemic inflammatory response syndrome and multiple organ dysfunction, and failure. This review attempts an overview of these processes and addresses the question, "Can manipulation of fluid resuscitation influence the inflammatory response to injury and organ function". Results of randomised controlled prospective clinical studies suggest that limiting the sodium and chloride input and optimal use of synthetic colloids, which are well retained in the vascular space, can reduce the inflammatory response to injury and improve organ function.

Fluid therapy in sepsis with capillary leakage

Sepsis is associated with a profound intravascular fluid deficit due to vasodilatation, venous pooling and capillary leakage. Fluid therapy is aimed at restoration of intravascular volume status, haemodynamic stability and organ perfusion. Circulatory stability following fluid resuscitation is usually achieved in the septic patient at the expense of tissue oedema formation that may significantly influence vital organ function. The type of fluid therapy, crystalloid or colloid, in sepsis with capillary leakage remains an area of intensive and controversial discussion. The current understanding of the physiology of increased microvascular permeability in health and sepsis is incomplete. Furthermore, there is a lack of appropriate clinical study end-points for fluid resuscitation. This review considers critically the clinical and experimental data analysing the assessment of capillary leakage in sepsis and investigating the effects of different fluid types on increased microvascular permeability in sepsis.

Colloid solutions for fluid resuscitation

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

REVIEWER'S CONCLUSIONS

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

[Effects of plasma substitutes on hemostasis]

OBJECTIVE

Data synthesis on haemostasis effects of cristalloids and colloids and clinical implications for their use for plasma volume replacement.

DATA SOURCES

Data were searched in the Medline database from 1954 to 2000 using the following key-words: cristalloids, colloids, albumin, gelatin, dextran, hydroxyethyl starch, haemostasis, von Willebrand disease, haemodilution.

DATA EXTRACTION

Publications from 1954 to 1990 were selected depending on the quality of their methodology. Most of articles published after 1990 and all types including case report were accepted.

DATA SYNTHESIS

Cristalloids induces a moderate hypercoagulable state with 10 to 30% haemodilution. Hypocoagulation is observed above 50% haemodilution. Albumin does not impair hemostasis except with a 50% or more haemodilution where hypocoagulation is observed. Dextran dramatically impairs haemostasis and fibrinolysis. With increasing dose, a progressive decrease of all von Willebrand multimers, mostly the largest, is observed. Till 50% haemodilution, gelatin has a moderate impact on hemostasis, but platelet aggregation is moderately modified. However this moderate impairment of haemostasis may potentiate the haemostatic effect of other colloids when used in association with gelatin. More than 30% haemodilution with hydroxyethyl starch (HES) has a serious effect in vitro on platelet function and fibrinoformation. In most studies in human, less than 20 ml.kg-1 plasma volume replacement has no clinical impact, but in some evaluations postoperative bleeding is more important with HES, particularly HES 450, in comparison to other colloids. With HES 450 and HES 200 highly substituted (0.6 of degree of substitution) intravascular cumulation of large molecules leads to type I von Willebrand syndrome when doses overtake 80 ml.kg-1. Dextran and HES are prohibited in patients with impaired haemostasis due to congenital disease (haemophilia and von Willebrand disease) or acquired defect (thrombocytopenia). Caution is required in patients with renal failure or receiving antithrombotic or non-steroidal anti-inflammatory agents. Patients without a haemorrhagic diathesis must not received more than 1.5 g.kg-1.j-1 of dextran and restrictive conditions of use must be respected with HES.

CONCLUSION

Except isotonic cristalloids, all colloids induce haemostastic changes particularly for haemodilution over 30%. Effects are more pronounced with HES and dextran.

Hydroxyethylstarch as a Risk Factor for Acute Renal Failure

Hypovolaemia is extremely common among surgical and intensive care patients. The best strategy for volume replacement therapy has been the focus of debate for several years. The lack of acceptance of hydroxyethylstarch (HES) for volume replacement therapy is most likely due to reports of abnormal coagulation and to recently published studies indicating negative effects of HES on renal function. All HES solutions are not created equal - they widely differ with regard to their physicochemical characteristics (concentration, mean molecular weight (Mw), degree of substitution [DS], C2/C6-substitution ratio). These differences have important consequences for adverse effects such as alterations in the coagulation process and on kidney function. Conflicting results about the effects of different HES solutions on renal function may also be due to varying clinical protocols, selection of patients, and different criteria for volume replacement. Theoretical and documented hazards are associated with each kind of volume replacement therapy. There appears to be no reason to banish modern HES preparations with a low or medium Mw (e.g. 70, 130 or 200 kD) and a low DS (0.4 or 0.5) in patients without pre-existing kidney dysfunction. In patients with known renal dysfunction (e.g. plasma creatinine level >3 mg/dl), all HES preparations should be used cautiously and other volume replacement regimens (e.g. gelatins) should be considered since no convincing data are yet available for the latest generation of HES (Mw 130; DS 0.4).

Effects of colloidal resuscitation fluids on the neutrophil respiratory burst

BACKGROUND

Experimental studies have revealed that gelatin and HES produce increased neutrophil respiratory burst activity. It was investigated whether 3-percent gelatin (MW 35,000) and three types of 6-percent HES (MW 70,000; degree of substitution, 0.5; 200,000/0.5; 450,000/0.7) preparations can influence superoxide anion production during respiratory burst under clinical conditions.

STUDY DESIGN AND METHODS

Blood samples were obtained from 40 patients before and 1 hour after the infusion, before anesthesia and surgical treatment. After stimulation with bacteria (Escherichia coli), the respiratory burst was measured by oxidation of nonfluorescent dihydrorhodamine 123 to the fluorescent rhodamine 123 by the use of flow cytometry.

RESULTS

Respiratory burst activity decreased significantly (p = 0.004) from the baseline (60.0 +/- 6.5%) to 1 hour after the administration of the low-molecular-weight HES preparation (55.0 +/- 6.8%). No significant differences in respiratory burst activity could be found after the administration of gelatin or medium-molecular-weight or high- molecular-weight HES solution.

CONCLUSION

The investigated administration of gelatin and medium- and high-molecular-weight HES preparations did not influence respiratory burst activity under clinical conditions. However, the neutrophil respiratory burst was impaired after the administration of low-molecular-weight HES. Neutrophil respiratory burst activity may vary according to the type of colloidal plasma substitutes administered.

Effects of different plasma substitutes on blood coagulation: a comparative review

OBJECTIVE

To compare the effects of different colloid plasma substitutes on blood coagulation and postoperative blood loss.

DATA SOURCES

Relevant studies were obtained from the medical literature.

STUDY SELECTION

Articles were selected that provided data on the effects of colloids on hemostasis and postoperative blood loss in humans. Studies comparing different colloids were looked for using MEDLINE and by searching through the references of studies as they were collected.

DATA SYNTHESIS

Articles were reviewed and relevant data were extracted and partly presented in comparative tables.

CONCLUSIONS

Dextran, gelatin, and hydroxyethyl starch (HES) all can induce a specific decrease of von Willebrand factor and factor VIII:c. Blood coagulation is most impaired by dextran and high molecular weight HES, both associated with increased postoperative blood loss. The effects of HES on blood coagulation have been shown to depend on its molecular weight and rate of elimination. Detrimental effects have been shown for high molecular weight HES. Medium molecular weight (MMW)-HES with a high degree of substitution (HES 200/0.62) and MMW-HES with high C2/C6 hydroxyethylation ratio (HES 200/0.5/13) are slowly degradable and have been shown to impair blood coagulation after repeated administration. Rapidly degradable HES 200/0.5/6 and gelatin-based plasma expanders appear not to impair hemostasis. However, based on the reviewed literature, all artificial colloids could potentially induce increased bleeding tendency after infusion of very large volumes and especially when given to patients with even mild forms of von Willebrand disease. In those circumstances, crystalloid solutions or alternatives such as plasma or albumin, although associated with other serious complications, could be considered.

Microparticle-containing oncotic solutions augment in-vitro clot disruption by ultrasound

Echocardiographic contrast agents enhance blood clot disruption by ultrasound. It has been suggested that the microbubbles add nuclei for the enhancement of cavitation by ultrasound. However, microbubbles are rapidly destroyed by the ultrasound energy. We assessed whether non-gas filled colloidal solutions (hyperoncotic medium molecular hydroxyethyl starch and degraded gelatin polypeptides) will facilitate clot disruption by ultrasound. In two separate experiments human blood clots, 200-400 mg in weight, were weighed and then immersed for 15 seconds in 10 ml normal saline solution containing 0%, 0.1%, 1%, 2%, and 5% of hyperoncotic medium molecular hydroxyethyl starch or 0%, 0.035%, 0.175%, 0.35%, and 0.7% degraded gelatin polypeptides. Clots were randomized to 10 seconds 20 kHz ultrasound or immersion without ultrasound. After treatment, the clots were reweighed, and the percent difference in weight was calculated. Non-gas filled microparticle-containing solutions such as hyperoncotic medium molecular hydroxyethyl starch and degraded gelatin polypeptides significantly augmented blood clot disruption by ultrasound. The effect is dependent on the colloidal solution concentration with maximal effect achieved with 1% hyperoncotic medium molecular hydroxyethyl starch and 0.35% degraded gelatin polypeptides.

Randomized trial of hydroxyethyl starch versus gelatine for trauma resuscitation

BACKGROUND

Previous studies have demonstrated the rapid increase in systemic capillary permeability after blunt trauma and its association with poor outcome. There are theoretical advantages in resuscitation with colloid fluids, which are well retained in the vascular compartment during times of capillary leak. The aim of this study was to compare the effects of posttrauma resuscitation with hydroxyethyl starch (HES) (molecular mass, 250 kDa) or gelatine (molecular mass, 30 kDa), the hypothesis being that HES would reduce capillary leak.

METHODS

Forty-five patients suffering blunt trauma were randomized on admission to receive either gelatine (Gelofusine) (n = 21) or HES (Pentaspan) (n = 24) for the first 24 hours, after which the choice of fluid was at the discretion of the clinician. The mean Injury Severity Score for the HES and gelatine groups were 20.0 (range, 9-41) and 18.1 (range, 9-32), respectively (p = 0.43). Capillary permeability was assessed by urine albumin excretion rate for the first 24 hours. For 5 days the daily mean P(O2)/F(IO2) ratio, serum C-reactive protein, hemoglobin, white cell and platelet counts, prothrombin, and activated partial thromboplastin time were recorded.

RESULTS

Capillary permeability was lower in HES-treated patients during the first 24 hours. Log mean (95% confidence interval) albumin excretion rate for gelatine and HES groups at 6 hours were 117.5 (84.9) and 46.8 (24.3) microg/min (p = 0.011), at 12 hours were 54.9 (30.0) and 17.2 (7.6) microg/min (p = 0.001), and at 24 hours were 50.5 (23.4) and 23.6 (16.3) microg/min (p = 0.030), respectively. The mean (95% confidence interval) P(O2)/F(IO2) ratio for the HES and gelatine groups 48 hours after admission were 324 (44) and 267 (43) mm Hg, respectively (p = 0.03). The mean (95% confidence interval) serum C-reactive protein in the HES and gelatine groups 24 hours after admission were 72.4 (19.2) and 105.7 (30.1) mg/L, respectively (p = 0.03). There were no significant differences in any of the hematologic parameters during the first 48 hours.

CONCLUSION

The results suggest that compared with gelatine, resuscitation with HES reduces posttrauma capillary leak.

Activity of blood coagulation and fibrinolysis during and after hydroxyethyl starch (HES) colloidal volume replacement

OBJECTIVES

To examine the effect of medium molecular weight hydroxyethyl starch on protein C levels and the changes in the activation state of blood platelets, coagulation and fibrinolyis during and after 5 day of its infusion.

DESIGN AND METHODS

Fifty male patients (mean age: 47 years, range 45-50 years) who required prostatectomy for benign prostatic hyperplasia were divided into two equal groups. One group was given 15 mL/kg body weight (mean volume 1000 mL +/- 100 mL) of 6% hydroxyethyl starch (HES) 200/0.5, the other received an equal volume of 5% human albumin during the operation. Blood samples were collected immediately before infusion (baseline values) and at 20, 40, 60, 90, 240, and 480 min after the infusion started then daily for the next 5 days postoperatively. Hematocrit, factor VIII:C, thrombin-antithrombin III complex; the anticoagulant protein C levels; the fibrinolytic parameters tissue type plasminogen activator (t-PA), and the fibrinolytic product D-Dimer and the platelet aggregation activity were measured.

RESULTS

The data obtained did not detect any significant differences between HES and human albumin in the plasma levels of thrombin-antithrombin III complex, protein C, tissue-type plasminogen activator and the fibrin split products D-Dimer. Factor VIII:C and platelet aggregation were significantly lower in the hydroxyethyl starch group in comparison with albumin. Baseline values were attained postoperatively for factor VIII:C and platelet aggregation by the first and fifth days, respectively.

CONCLUSION

The lowering effect of medium molecular weight hydroxyethyl starch on factor VIII:C would not be attributed to increased proteolytic activity of protein C on this coagulation cofactor because there is a nonsignificant change in protein C levels.

No beneficial effects of isocolloidoosmotic synthetic colloid addition to St. Thomas Hospital cardioplegic solution in ischemia-reperfusion injury in isolated perfused rat hearts

1. Cardioplegic solutions provide the opportunity to operate on a nonbeating heart and to protect the heart against ischemic injury during cardiac surgery. The components of these solutions are constantly being modified in an effort to find the optimal solution. We studied the effects of colloidal volume replacers such as dextran, HES and gelatin as an isocolloidoosmotic addition to St. Thomas Hospital cardioplegic solution in ischemia-reperfusion injury of isolated rat hearts. 2. In the control group, after a stabilization period of 20 min, the hearts were arrested with St. Thomas Hospital cardioplegic solution for 3 min, then subjected to 30 min of global ischemia. Hearts then were reperfused for 10 min. In the experimental groups, the protocol was the same, but either HES 200/0.5 (50 g/L), modified fluid gelatin (30 g/l) or dextran 70 (25 g/L) were added to the St. Thomas Hospital solution. 3. All hearts were compared for their preischemic and postischemic contractility, heart rate, contractility rate product, coronary flow, lactate dehydrogenase, creatine phosphokinase enzyme leakage and wet/dry weight ratio. 4. All groups had similar contractility (for control, HES, gelatin and dextran groups the values at minute 10 of reperfusion were 59+/-9, 56+/-11%, 61+/-14%, 49+/-14% of initial values [P>0.05, respectively]) and enzyme leakage (lactate dehydrogenase 4.1+/-1.0, 8.1+/-1.5, 5.8+/-1.4, 3.7+/-1.2 [P>0.05] and for creatine phosphokinase 3.9+/-2.5, 6.4+/-3.7, 5.5+/-1.3, 5.5+/-0.8, P>0.05] IU xmin(-1) x g dry tissue(-1) in the reperfusion period, respectively) results as compared with the control group. 5. The addition of isocolloidoosmotic colloids to the cardioplegic solution did not appear to enhance the effectiveness of the crystalloid St. Thomas Hospital cardioplegic solution. If a colloid is to be chosen as a plasma replacer or an additive to priming solution in the preoperative period, or during open-heart surgery, it should be modified fluid gelatin-for no sign of cardiodepression was determined with the use of this agent.