The appropriate role of colloids in managing fluid imbalance: a critical review of recent meta-analytic findings

Cross-Sectional Guidelines for Therapy with Blood Components and Plasma Derivatives: Chapter 5 Human Albumin - Revised

Chapter 5 'Human Albumin' that was suspended on January 10, 2011 has been completed and updated in the present version.

Albumin: physiologic and clinical effects on lung function

Fluid resuscitation is one of the most frequent and necessary practices in clinical medicine and is an integral part of the initial stabilization of critically ill, hypovolemic patients. Longstanding debate and conflicting evidence surround the use of both colloid and crystalloid fluid resuscitation in these patients. The basis of this debate is heavily rooted in the physiological understanding of Starling's forces. In this review, we aim to highlight the ongoing debate of albumin versus crystalloid resuscitation both broadly and as it relates to lung function, and will discuss the current state-of-the-art, starting from an historic perspective and progressing through a review of both physiologic and clinical evidence. Despite the biologic and physiologic plausibility of therapeutic benefit, the current evidence base does not support the routine use of albumin administration to improve patient survival or prevent respiratory dysfunction.

Do colloids in comparison to crystalloids for fluid resuscitation improve mortality?

Permanent neurological impairment or death arising from hospital-acquired hyponatremia in both children and adults is well documented. The choice of intravenous fluids for fluid resuscitation in critically ill patients is a top priority in evidence-based medicine. The question of whether colloids in comparison to crystalloids can improve mortality in such cases remains to be answered. Well powered, randomized clinical trials addressing the comparative efficacy of different types of intravenous fluids is a high priority as is the ethical justification for such trials. The understanding of the pathophysiological process serves important information on clinical practice.

Small-volume resuscitation with hyperoncotic albumin: a systematic review of randomized clinical trials

Background

Small-volume resuscitation can rapidly correct hypovolemia. Hyperoncotic albumin solutions, long in clinical use, are suitable for small-volume resuscitation; however, their clinical benefits remain uncertain.

Methods

Randomized clinical trials comparing hyperoncotic albumin with a control regimen for volume expansion were sought by multiple methods, including computer searches of bibliographic databases, perusal of reference lists, and manual searching. Major findings were qualitatively summarized. In addition, a quantitative meta-analysis was performed on available survival data.

Results

In all, 25 randomized clinical trials with a total of 1,485 patients were included. In surgery, hyperoncotic albumin preserved renal function and reduced intestinal edema compared with control fluids. In trauma and sepsis, cardiac index and oxygenation were higher after administration of hydroxyethyl starch than hyperoncotic albumin. Improved treatment response and renal function, shorter hospital stay and lower costs of care were reported in patients with liver disease receiving hyperoncotic albumin. Edema and morbidity were decreased in high-risk neonates after hyperoncotic albumin administration. Disability was reduced by therapy with hyperoncotic albumin in brain injury. There was no evidence of deleterious effects attributable to hyperoncotic albumin. Survival was unaffected by hyperoncotic albumin (pooled relative risk, 0.95; 95% confidence interval 0.78 to 1.17).

Conclusion

In some clinical indications, randomized trial evidence has suggested certain benefits of hyperoncotic albumin such as reductions in morbidity, renal impairment and edema. However, further clinical trials are needed, particularly in surgery, trauma and sepsis.

Comparison of the effects of gelatin and a modern hydroxyethyl starch solution on renal function and inflammatory response in elderly cardiac surgery patients

BACKGROUND

The effects of hydroxyethylstarch (HES) 130/0.4 6% and gelatin 4% on inflammation, endothelial integrity, and renal function after cardiac surgery were compared.

METHODS

Sixty patients aged >80 yr undergoing cardiac surgery were randomized to receive gelatin (n=30) or HES 130/0.4 (n=30). The colloid was used in the priming of the cardiopulmonary bypass circuit (500 ml) and for volume replacement until the second postoperative day (POD). Serum creatinine, creatinine clearance, IL-6, IL-10, intercellular adhesion molecule-1 (sICAM-1), urinary glutathione transferase-alpha, and neutrophil gelatinase-associated lipocalin (NGAL) were measured perioperatively. Serum creatinine was also reported approximately 60 days after discharge.

RESULTS

The mean(sd) volume of gelatin infused was 4180(440) ml, which was greater than the volume of HES infused 2910(330) ml (P=0.002). The mean(sd) volume of serum creatinine on the first POD was 151(24) micromol litre(-1) in the gelatin group and 126(13) micromol litre(-1) in the HES group (P=0.004). Values for the second POD were 161(0.26) and 133(16) micromol litre(-1), respectively (P=0.004). Creatinine clearance was lower in the gelatin group on the first POD [37(7) vs 46(8) ml min(-1) 1.73 m2 (P=0.004)] and the second POD [32(8) vs 45(10) ml min(-1) 1.73 m2 (P=0.002)]. Kidney function approximately 60 days after discharge did not differ between the groups. IL-6, IL-10, and sICAM-1 were significantly lower in the HES group than in the gelatin group on the first and second PODs. Urinary alpha-GST increased in both groups to a comparable extent. Urinary NGAL concentrations were higher in the gelatin than in the HES patients 5 h after surgery and on the first and second PODs.

CONCLUSIONS

In cardiac surgery patients aged >80 years, volume therapy with HES 130/0.4 6% was associated with less marked changes in kidney function and a less marked endothelial inflammatory response than gelatin 4%.

The phenomenon of "fluid creep" in acute burn resuscitation

Several reports have documented that modern burn patients receive far more resuscitation fluid than predicted by the Parkland formula-a phenomenon termed "fluid creep." This article reviews the incidence, consequences, and possible etiologies of fluid creep in modern practice and uses this information to propose some therapeutic strategies to reduce or eliminate excessive fluid resuscitation in burn care. A literature review was performed of historical references that form the foundation of modern fluid resuscitation, as well as reports of fluid creep and its consequences. The original Parkland formula required a 24-hour volume of 4 ml/kg/%TBSA lactated Ringer's solution followed by an infusion of 0.3-0.5 ml/kg/ %TBSA plasma. Modern iterations of this formula have omitted the colloid bolus. Numerous exceptions to the formula have been noted, most consistently patients with inhalation injuries. In contrast, recent reports document greatly increased fluid requirements in unselected patients, which seems to consist largely of progressive edema formation in unburned areas, increasing after the first 8 hours post-burn. This has been linked to occurrence of the abdominal compartment syndrome and other serious complications. Strategies to reduce fluid creep include the avoidance of early overresuscitation, use of colloid as a routine component of resuscitation or for "rescue," and adherence to protocols for fluid resuscitation. Fluid creep is a significant problem in modern burn care. Review of original investigations of burn shock, coupled with modern reports of fluid creep, suggests several mechanisms by which this problem can be controlled. Prospective trials of these therapies are needed to confirm their effectiveness.

Renal impact of fluid management with colloids: a comparative review

BACKGROUND AND OBJECTIVES

Colloids such as hydroxyethyl starch (HES), gelatin, dextran and albumin are useful for maintaining renal perfusion and function. The comparative renal effects of colloids have not been previously reviewed.

METHODS

Computer searches of the MEDLINE and EMBASE bibliographic databases and the Cochrane Library were conducted using the search terms: colloids; hetastarch; gelatin; dextrans; serum albumin; kidney failure; cardiac surgical procedures; and kidney transplantation. Relevant studies were also sought through hand searching and examination of reference lists. Results of identified studies were qualitatively summarized with account taken for potential confounding factors.

RESULTS

The three artificial colloids HES, gelatin and dextran all exhibited troublesome renal side-effects. Randomized trials have demonstrated adverse renal effects of HES in sepsis and surgery. Undesirable renal effects are common to all available HES solutions regardless of molecular weight, substitution or C2/C6 ratio. While some of its effects may be less severe than those of HES, gelatin also can adversely affect the kidney. A negative renal impact of dextran is well-established, although this colloid is now less extensively used than formerly. As the normal endogenous colloid, albumin exhibits a wide margin of renal safety, although albumin overdose needs to be avoided. Albumin also appears to exert protective effects on the kidney such as inhibition of apoptosis and scavenging of reactive oxygen species.

CONCLUSIONS

Colloids display important differences in their actions on the kidney. These contrasting renal effects should be considered in making fluid management decisions.

Morbidity in hospitalized patients receiving human albumin: a meta-analysis of randomized, controlled trials

OBJECTIVE

To determine the effect of albumin administration on morbidity in acutely ill hospitalized patients.

DATA SOURCE

Computer searches of MEDLINE, EMBASE, and the Cochrane Library; hand searches of journals and Index Medicus; inquiries with investigators and fluid product suppliers; and examination of reference lists. No language or time period restrictions were adopted.

STUDY SELECTION

Randomized, controlled trials comparing the administration of albumin with that of crystalloid, no albumin, or lower-dose albumin.

DATA EXTRACTION

Two investigators independently extracted data. The primary endpoint for the meta-analysis was morbidity, defined as the incidence of complications, including death. Trial quality was evaluated by blinding, allocation concealment, presence of morbidity as a study endpoint, and individual patient crossover.

DATA SYNTHESIS

Seventy-one trials were included in the categories of surgery or trauma, burns, hypoalbuminemia, high-risk neonates, ascites, and other indications. The 3,782 randomized patients in the included trials experienced a total of 3,287 complications, including 515 deaths and 2,772 cardiovascular, gastrointestinal, hepatic, infectious, renal, respiratory, and other complications. Albumin significantly reduced overall morbidity, with a risk ratio of 0.92 (confidence interval [CI], 0.86-0.98). Control group albumin dose significantly affected the incidence of complications (p = .002). In 32 trials with no albumin administered to the control group, the risk ratio was 0.77 (CI, 0.67-0.88) compared with 0.89 (CI, 0.80-1.00) in 20 trials with control patients receiving low-dose albumin and 1.07 (CI, 0.96-1.20) in 19 trials with moderate-dose control group albumin.

CONCLUSIONS

Albumin reduces morbidity in acutely ill hospitalized patients. Concomitant administration of albumin in the control group can obscure the effects of albumin on clinical outcome in randomized trials.

Fluid resuscitation with colloids of different molecular weight in septic shock

OBJECTIVE

The aim of this study was to investigate the short-term effect of fluid resuscitation with 4% modified fluid gelatine (GEL) versus 6% hydroxyethyl starch (HES) on haemodynamics and oxygenation in patients with septic shock and acute lung injury (ALI).

DESIGN

Prospective randomised clinical trial.

SETTING

Twenty-bed intensive care unit in a university hospital.

PATIENTS

Thirty hypovolemic patients (intrathoracic blood volume index, ITBVI <850 ml/m(2)) in septic shock with ALI were randomised into HES (mean molecular weight: 200,000 Dalton, degree of substitution 0.6) and GEL (mean molecular weight: 30,000 Dalton) groups (15 patients each).

INTERVENTIONS

For fluid resuscitation 250 ml/15 min boluses (max. 1,000 ml) were given until the end point of ITBVI >900 ml/m(2) was reached. Repeated haemodynamic measurements were done at baseline (t(b)), at the end point (t(ep)) then at 30 min and 60 min after the end point was reached (t(30), t(60)). Cardiac output, stroke volume, extravascular lung water (EVLW), and oxygen delivery was determined at each assessment point. For statistical analysis two-way ANOVA was used.

MEASUREMENTS AND RESULTS

ITBVI, cardiac index, and oxygen delivery index increased significantly at t(ep) and remained elevated for t(30) and t(60), but there was no significant difference between the two groups. The increase in the ITBVI by 100 ml of infusion was similar in both groups (HES: 26+/-19 ml/m(2) vs GEL: 30+/-19 ml/m(2)). EVLW, remained unchanged, and there was no significant difference between the groups (HES, t(b): 8+/-6, t(60): 8+/-6; GEL, t(b): 8+/-3, t(60): 8+/-3 ml/kg). The PaO(2)/FiO(2) did not change significantly over time or between groups (HES, t(b): 207+/-114, t(60): 189+/-78; GEL, t(b): 182+/-85, t(60): 182+/-85 mmHg).

CONCLUSION

The results of this study indicate that both HES and GEL infusions caused similar short-term change in ITBVI in septic shock, without increasing EVLW or worsening oxygenation.

Safety of human albumin—serious adverse events reported worldwide in 1998–2000 † †Declaration of interest. This investigation was supported by an unrestricted grant from the Plasma Protein Therapeutics Association. The sponsor played no role in the analysis and interpretation of data or the preparation and submission of the manuscript. Hygeia Associates is an independent organization specializing in the statistical analysis of biomedical research data and is in no way affiliated with the sponsor, either directly or indirectly. None of the co-investigators in this study has any conflict of interest to declare

BACKGROUND

Previous pharmacovigilance studies have indicated a low rate of adverse events in patients receiving human albumin. However, the incidence of adverse events is likely to have been underestimated because of under-reporting. A more accurate estimate may be possible during a period such as 1998-2000, when awareness regarding albumin safety was heightened by publication of a meta-analysis.

METHODS

All serious adverse event reports received, and total doses of albumin distributed worldwide from the beginning of 1998 to the end of 2000 by 10 major suppliers of therapeutic human albumin were compiled.

RESULTS

Distributed albumin doses totalled 1.62 x 10(7). The total numbers of non-fatal and fatal serious adverse events reported were 198 and 13, respectively. The incidence of all reported serious non-fatal and fatal adverse events was 5.28 per 10(6) doses (CI 1.60-17.4 per 10(6) doses). For non-fatal serious adverse events only, the observed incidence was 4.65 per 10(6) doses (CI 1.34-16.2 per 10(6) doses). No patient death was classified as probably related to albumin administration. The observed incidence of fatal serious adverse events possibly related to albumin was 0.185 per 10(6) doses (CI 0.0597-0.574 per 10(6) doses). The observed incidence of all non-fatal and fatal serious adverse events was significantly higher during the 1998-2000 period as compared with 1990-1997 (incidence rate ratio 4.98; CI 3.94-6.29), probably chiefly as a result of reduced under-reporting.

CONCLUSIONS

Although the observed incidence of adverse events is likely to be an underestimate, nevertheless both non-fatal and fatal serious adverse events in albumin recipients appear to be rare. These results add further support to the excellent safety record of human albumin.

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.

Crystalloids and colloids in trauma resuscitation: a brief overview of the current debate

BACKGROUND

Controversy regarding crystalloids or colloids for resuscitation has existed for over five decades, and large numbers of clinical trials have failed to resolve the controversy. In fact, the limitations of these studies have intensified the debate. This overview aims to revisit the debate of fluid resuscitation in trauma patients by critically appraising the meta-analyses on the subject.

METHODS

This study was a critical analysis of six meta-analyses found by MEDLINE search.

RESULTS

Overall, the choice of fluid may have a small or no effect on mortality. In trauma, the use of colloids is associated with a trend toward increased mortality.

CONCLUSION

There is an urgent need for well-designed clinical trials. Because of many limitations, meta-analysis should be interpreted with caution, possibly as hypothesis generating. However, even considering all weaknesses and nuances of interpretation, the meta-analyses reviewed suggest that trauma patients should continue to be resuscitated with crystalloids.

Albumin use in neurosurgical critical care

STUDY OBJECTIVE

To examine the use of albumin in patients receiving neurosurgical intensive care.

DESIGN

Survey and chart review of albumin use in neurosurgical intensive care units.

SETTING

University of Kentucky Chandler Medical Center and American Brain Injury Consortium (ABIC).

SUBJECTS

Thirty-eight patients who underwent neurosurgery at the University of Kentucky Chandler Medical Center; members of the ABIC.

INTERVENTIONS

Chart review with attention to administration of albumin; mailed survey to 200 ABIC members.

MEASUREMENTS AND MAIN RESULTS

Patients admitted to the neurosurgical intensive care unit at the University of Kentucky Chandler Medical Center over a 6-month interval were evaluated. Albumin, either 5% or 25%, was prescribed for approximately 25% of patients. The indications for use were vasospasm and maintenance of cerebral perfusion pressure. The response rate for the ABIC survey was 39%. Respondents stated that normal saline and albumin were both primary fluid choices for the treatment of vasospasm. Twenty-two percent reported a reduction in albumin prescribing following a formal warning statement issued by the Food and Drug Administration regarding the use of albumin in critically ill patients.

CONCLUSIONS

Chart review revealed the primary indications for albumin in the neurosurgical intensive care unit, and our survey data demonstrated the lack of consensus among neurosurgeons regarding their fluid of choice for neurosurgery indications. Prospective, randomized investigations comparing colloids to crystalloids in patients receiving neurosurgical intensive care are required to help define the role of albumin in neurosurgery patients.