Colloid solutions for fluid resuscitation

Modifiable Risk Factors for Delayed Graft Function After Deceased Donor Kidney Transplantation

PURPOSE

Delayed graft function is a major complication after kidney transplantation affecting patients' long-term outcome. The aim of this study was to identify modifiable risk factors for delayed graft function after deceased donor kidney transplantation.

METHODS

This is a single-center retrospective cohort study of a university transplantation center. Univariate and multivariate step-wise logistic regression analysis of patient-specific and procedural risk factors were conducted.

RESULTS

We analyzed 380 deceased donor kidney transplantation patients between October 30, 2008 and December 30, 2017. The incidence of delayed graft function was 15% (58/380). Among the patient-specific risk factors recipient diabetes (2.8 [1.4-5.9] odds ratio [OR] [95% confidence interval [CI]]), American Society of Anesthesiologist score of 4 (2.7 [1.2-6.5] OR [95% CI]), cold ischemic time >13 hours (2.8 [1.5-5.3] OR [95% CI]) and donor age >55 years (1.9 [1.01-3.6] OR [95% CI]) revealed significance. The significant intraoperative, procedural risk factors included the use of colloids (3.9 [1.4-11.3] OR [95% CI]), albumin (3.0 [1.2-7.5] OR [95% CI]), crystalloids >3000 mL (3.1 [1.2-7.5] OR [95% CI]) and mean arterial pressure <80 mm Hg at the time of reperfusion (2.4 [1.2-4.8] OR [95% CI]).

CONCLUSION

Patients undergoing deceased donor kidney transplantation with a mean arterial pressure >80 mm Hg at the time of transplant reperfusion without requiring excessive fluid therapy in terms of colloids, albumin or crystalloids >3000 mL are less likely to develop delayed graft function.

Resuscitation with centhaquin and 6% hydroxyethyl starch 130/0.4 improves survival in a swine model of hemorrhagic shock: a randomized experimental study

PURPOSE

To investigate the effects of the combination of centhaquin and 6% hydroxyethyl starch 130/0.4 (HES 130/0.4) in a swine model of hemorrhagic shock.

METHODS

Twenty Landrace-Large White pigs were instrumented and subjected to hemorrhagic shock. The animals were randomly allocated in two experimental groups, the control (group CO, n = 10) and the centhaquin groups (0.015 mg/kg, n = 10, group CH). Acute hemorrhage was induced by stepwise blood withdrawal (18 mL/min) from the internal jugular vein until MAP decreased to 40-45 mmHg, whereas anesthesia remained constant. All animals received HES 130/0.4 solution in the resuscitation phase until their mean arterial pressure (MAP) reached 90% of the baseline. The animals were observed for 60 min, during which no further resuscitation was attempted.

RESULTS

The total amount of blood and the bleeding time did not differ significantly between group CO and group CH (120 ± 13 vs. 120 ± 14 mL, p = 0.6; 20 ± 2 vs. 20 ± 1 min, p = 0.62, respectively). During the hemorrhagic phase, only a difference in heart rate (97.6 ± 4.4 vs. 128.4 ± 3.6 beats/min, p = 0.038) was observed between the two groups. The time required to reach the target MAP was significantly shorter in the centhaquin group compared to controls (13.7 ± 0.4 vs. 19.6 ± 0.84 min, p = 0.012). During the resuscitation phase, a statistical significant difference was observed in MAP (75.2 ± 1.6 vs. 89.8 ± 2.1 mmHg, p = 0.02) between group CO and group CH. During the observation phase, a statistical significant difference was observed in SVR (1109 ± 32.65 vs. 774.6 ± 21.82 dyn s/cm⁵, p = 0.039) and cardiac output (5.82 ± 0.31 vs. 6.9 ± 0.78 L/min, p = 0.027) between the two groups. Two animals of group CO and seven animals of group CH survived for 24 h (p = 0.008). We observed a marked increase in microvascular capillary permeability in group CO compared to group CH, with the wet/dry weight ratio being significantly higher in group CO compared to group CH (4.8 ± 1.6 vs. 3.08 ± 0.6, p < 0.001).

CONCLUSIONS

The combination of centhaquin 0.015 mg/kg and HES 130/0.4 resulted in shorter time to target MAP, lower wet-to-dry ratio, and better survival rates after resuscitation from hemorrhagic shock.

Effect of lactate versus acetate-based intravenous fluids on acid-base balance in patients undergoing free flap reconstructive surgeries

BACKGROUND AND AIMS

Use of lactated intravenous fluids during long surgeries could cause lactate accumulation and lactic acidosis. Acetate-based solutions could be advantageous as they are devoid of lactate. The primary aim of the study was to assess the effect of use of an acetated solution or Ringer's lactate (RL) as intraoperative fluid on lactate levels in patients without hepatic dysfunction undergoing prolonged surgeries.

MATERIAL AND METHODS

This was a prospective, randomized, controlled trial involving sixty patients belonging to American Society of Anesthesiologists Physical Status I to II undergoing major head and neck surgeries with free flap reconstruction. Patients were randomly allocated into two equal groups, Group sterofundin (SF) and Group RL. Group SF was started on acetate-based crystalloid solution (sterofundin B Braun®) and Group RL received RL intravenously at the rate of 10 ml/kg/h to maintain systolic blood pressure above 90 mmHg. Blood loss >20% was replaced with packed cells. Arterial blood gas analysis was done 2nd hourly till 8 h. Chi-square test was used to compare categorical variables. Independent sample t-test was used to compare means.

RESULTS

Intraoperative lactate levels were significantly high in RL group at 2, 4, 6, and 8 h. The pH was comparable between groups except at 8 h where RL group had a significantly lower pH than SF group (7.42 ± 0.1 vs. 7.4 ± 0.1). Sodium, potassium, chloride, bicarbonate, and pCO2did not show any significant difference between the groups.

CONCLUSION

Use of acetate-based intravenous solutions reduced levels of lactate in comparison with RL in patients undergoing free flap reconstructive surgeries.

Cochrane: the unfinished symphony of research synthesis

The NHS needs valid information on the safety and effectiveness of healthcare interventions. Cochrane systematic reviews are an important source of this information. Traditionally, Cochrane has attempted to identify and include all relevant trials in systematic reviews on the basis that if all trials are identified and included, there should be no selection bias. However, a predictable consequence of the drive to include all trials is that some studies are included that are not trials (false positives). Including such studies in reviews might increase bias. More effort is needed to authenticate trials to be included in reviews, but this task is bedevilled by the enormous increase in the number of 'trials' conducted each year. We argue that excluding small trials from reviews would release resources for more detailed appraisal of larger trials. Conducting fewer but broader reviews that contain fewer but properly validated trials might better serve patients' interests.

The clinical effectiveness of pre-hospital intravenous fluid replacement in trauma patients without head injury: a systematic review

Traditionally, the management of bleeding trauma patients has included early rapid fluid replacement on scene. However, evidence shows that a delay to definitive treatment (control of bleeding) may be harmful and UK policy advocates minimal delay on scene with intravenous fluids being administered in transit to hospitals. This paper systematically reviews the evidence for administering fluids in pre-hospital trauma patients with no head injury. Randomized controlled trials comparing immediate and delayed fluid replacement were sought using formal search strategies. Study selection, quality assessment and data extraction were performed independently by two reviewers using pre-defined criteria. We found no evidence to suggest that pre-hospital fluid administration is beneficial. There is some evidence that it may be harmful and that patients do comparatively well when fluids are withheld. However, this evidence is not conclusive, particularly for blunt trauma, and is not sufficient to disprove current UK policy, which recommends hypotensive resuscitation.

Beautiful small: Misleading large randomized controlled trials? The example of colloids for volume resuscitation

In anesthesia and intensive care, treatment benefits that were claimed on the basis of small or modest-sized trials have repeatedly failed to be confirmed in large randomized controlled trials. A well-designed small trial in a homogeneous patient population with high event rates could yield conclusive results; however, patient populations in anesthesia and intensive care are typically heterogeneous because of comorbidities. The size of the anticipated effects of therapeutic interventions is generally low in relation to relevant endpoints. For regulatory purposes, trials are required to demonstrate efficacy in clinically important endpoints, and therefore must be large because clinically important study endpoints such as death, sepsis, or pneumonia are dichotomous and infrequently occur. The rarer endpoint events occur in the study population; that is, the lower the signal-to-noise ratio, the larger the trials must be to prevent random events from being overemphasized. In addition to trial design, sample size determination on the basis of event rates, clinically meaningful risk ratio reductions and actual patient numbers studied are among the most important characteristics when interpreting study results. Trial size is a critical determinant of generalizability of study results to larger or general patient populations. Typical characteristics of small single-center studies responsible for their known fragility include low variability of outcome measures for surrogate parameters and selective publication and reporting. For anesthesiology and intensive care medicine, findings in volume resuscitation research on intravenous infusion of colloids exemplify this, since both the safety of albumin infusion and the adverse effects of the artificial colloid hydroxyethyl starch have been confirmed only in large-sized trials.

Anesthesia for bone replacement surgery

Advances in clinical medicine, improved understanding of pathophysiology, and the extensive application of medical technology have projected hitherto high risk and poor outcome surgical procedures into the category of routine and relatively good outcome surgeries. Bone replacement surgery is one amongst these and is wrought with a multitude of perioperative complexities. An understanding of these goes a long way in assisting in the final outcome for the patient. Here we present a review of the literature covering various issues involved during the different stages of the perioperative period.

Comparative effectiveness of medical interventions in adults versus children

OBJECTIVE

To estimate the comparative effectiveness of medical interventions in adults versus children.

STUDY DESIGN

We identified from the Cochrane Database of Systematic Reviews (Issue 1, 2007) meta-analyses with data on at least 1 adult and 1 pediatric randomized trial with binary primary efficacy outcome. For each meta-analysis, we calculated the summary odds ratio of the adult trials and the pediatric trials, respectively; the relative odds ratio (ROR) of the adult versus pediatric odds ratios per meta-analysis; and the summary ROR across all meta-analyses. ROR <1 means that the experimental intervention is more unfavorable in children than adults.

RESULTS

Across 128 eligible meta-analyses (1051 adult and 343 pediatric trials), the summary ROR did not show a statistically significant difference between adults and children (0.96; 95% confidence intervals, 0.86 to 1.08). However, in all meta-analyses except for 1, the individual ROR's 95% confidence intervals could not exclude a relative difference in efficacy over 20%. In two-thirds, the relative difference in observed point estimates exceeded 50%. Nine statistically significant discrepancies were identified; 4 of them were also clinically important.

CONCLUSIONS

Treatment effects are on average similar in adults and children, but available evidence leaves large uncertainty about their relative efficacy. Clinically important discrepancies may occur.

Ischemic heart disease

Because of changing demographics, increasing numbers of patients with IHD are presenting for noncardiac surgery, and the risks of perioperative morbidity and mortality are significant. The Lee Cardiac Risk Index is applicable in defining perioperative cardiac risk: however, ACC/AHA guidelines may not be applicable comprehensively. The role of biomarkers in risk stratification still needs to be defined. Structured management protocols that help assess, diagnose, and treat patients with IHD preoperatively are likely to help decrease postoperative morbidity and mortality, but clearly are not applicable to all patients. Augmented hemodynamic control with beta-blockers or alpha-2 agonists and modulating inflammation by statins can play an important role in improving outcomes in many patients with IHD; preoperative coronary revascularization may be of limited value. Intraoperative anesthetic management that minimizes hemodynamic perturbations is important; however, the choice of a particular technique typically is not critical. Of critical importance is the postoperative management of the patient. Postoperative myocardial injury should be identified, evaluated, and managed aggressively. Secondary stresses such as sepsis, extubation, and anemia, which can increase demand on the heart, should be treated or minimized. Clearly, optimal care of the patient with IHD entails closely coordinated assessment and management throughout the preoperative, intraoperative, and postoperative phases, if one is to optimize short- and long-term outcomes.

Fluid resuscitation in neonatal and pediatric hypovolemic shock: a Dutch Pediatric Society evidence-based clinical practice guideline

OBJECTIVE

To develop a clinical practice guideline that provides recommendations for the fluid, i.e. colloid or crystalloid, used for resuscitation in critically ill neonates and children up to the age of 18 years with hypovolemia.

METHODS

The guideline was developed through a comprehensive search and analysis of the pediatric literature. Recommendations were formulated by a national multidisciplinary committee involving all stakeholders in neonatal and pediatric intensive care and were based on research evidence from the literature and, in areas where the evidence was insufficient or lacking, on consensus after discussions in the committee.

RESULTS

Because of the lack of evidence in neonates and children, trials conducted in adults were considered. We found several recent meta-analyses that show excess mortality in albumin-treated groups, compared with crystalloid-treated groups, and one recent large randomized controlled trial that found evidence of no mortality difference. We found no evidence that synthetic colloids are superior to crystalloid solutions.

CONCLUSIONS

Given the state of the evidence and taking all other considerations into account, the guideline-developing group and the multidisciplinary committee recommend that in neonates and children with hypovolemia the first-choice fluid for resuscitation should be isotonic saline.

The effects of commonly used resuscitation fluids on whole blood coagulation

OBJECTIVES

Evidence on the effect of crystalloid and colloid resuscitation fluids on coagulation is confusing, with contradictory results from previous studies. This study was performed to test the effect on whole blood coagulation of a range of resuscitation fluids in vitro using a single method at a single dilution.

METHODS

Seven resuscitation fluids were tested in vitro at a dilution of 40%. Whole blood coagulation was measured using a Sonoclot analyser.

RESULTS

A crystalloid/colloid split of effect on coagulation in vitro was not seen. The time to clot formation with Gelofusine, dextran and hydroxyethyl starch was a greatly increased, whereas saline and Haemaccel had little effect, or were slightly procoagulant.

CONCLUSIONS

Some resuscitation fluids have a profound effect on coagulation. The confusion in the literature may result from the effect on coagulation being both fluid and dilution dependent, with no simple crystalloid/colloid split.

Appraisal of the evidence for the clinical use of FFP and plasma fractions

Randomised, controlled trials of good quality are a recognised means to robustly assess the efficacy of interventions in clinical practice. A systematic identification and appraisal of all randomised trials involving fresh frozen plasma (FFP) indicates that most clinical indications for FFP, as currently recommended by practice guidelines, are not supported by evidence from randomised trials. This chapter will largely consider the implications of some of the findings from this systematic review. Many published trials on the use of FFP have enrolled small numbers of patients, and provided inadequate information on the ability of the trial to detect meaningful differences in outcomes between the two patient groups. Other concerns about the design of the trials include the dose of FFP used, and the potential for bias; no studies had taken adequate account of the extent to which adverse effects might negate the clinical benefits of treatment with FFP. In addition, there is little evidence for the effectiveness of the prophylactic use of FFP. There is a pressing need to consider how best to develop new trials to determine the effectiveness of FFP. How this can be achieved can be illustrated by reference to studies of albumin in critical care. A recent, large and well-designed randomised trial (Saline versus Albumin Fluid Evaluation study; SAFE) in critical care found no evidence of an increase in mortality with the use of albumin compared to saline, which had been hypothesised in an earlier systematic review. How the study findings will actually now influence the clinical use of albumin remains to be seen. Although the SAFE trial showed no increase in mortality with albumin compared with saline, it is difficult to justify its use in critical care given its considerably greater cost.

A review of emergency equipment carried and procedures performed by UK front line paramedics on paediatric patients

OBJECTIVES

In 1997 a review of paramedic practice upon adult patients in the UK found many inconsistencies and deficiencies in basic care. A follow up review in 2002 identified widespread improvement in provision of equipment and skills to provide basic and advanced life support.Paediatric care was not assessed in either review. The authors conducted this study to identify current standards of care in paediatric paramedic practice and areas of potential improvement.

METHOD

A questionnaire designed to determine what equipment and skills were available to paramedics for the management of common or serious paediatric emergencies was sent to chief executives of the 32 NHS Ambulance Trusts in England and Wales.

RESULTS

The trend of expanding and standardising practice among adult patients has not extended to paediatric practice despite national guidelines from the Joint Royal Colleges Ambulance Liaison Committee (JRCALC). Furthermore there are some serious failings in the provision of care and skills. Many Trusts have not adopted JRCALC guidelines for the management of life threatening paediatric emergencies such as asthma, meningitis, and fluid replacement in hypovolaemia.

CONCLUSIONS

Ambulance Trusts not meeting standards set out in the JRCALC guidelines must address their areas of deficiency. Failure to do so endangers children's lives and leaves Trusts open to criticism.

Albumin and hydroxyethyl starch 130 kDa/0.4 improve filter clearance and haemocompatibility in haemo- and plasmafiltration—an in vitro study

BACKGROUND

Apart from their standard applications, haemofiltration (HF) and plasmafiltration (PF) may provide helpful therapy for sepsis, multiple organ- and acute liver-failure. Some colloids cause either decreases or increases in blood cell agglomeration. We hypothesized that solutions which reduce cell aggregability may lead to both improved filter clearance and better haemocompatibility due to decreasing rates of clogged hollow fibres.

METHODS

Heparinized porcine blood (5 IU/ml) was used in an in vitro circuit. The filter types tested were from GAMBRO: HF66D (effective membrane surface: 0.6 m2) and PF1000N (effective membrane surface: 0.15 m2). Albumin (ALB), hydroxyethyl starch (HES) 200/0.5, HES 130/0.4, gelatin (GEL) or normal saline (0.9%) were added to the blood (n = 6/group). Recirculation systems were run for 2 h. Spontaneous haemolysis and filter resistance >420 mmHg were selected as indications of maximal flow rates. Sieving coefficients were determined for 17 parameters at the lowest and highest blood flows and filtration rate.

RESULTS

Based on the filter types used, supplementation of ALB and HES130/0.4 led to an improved filter clearance without increasing the number of clogged capillary membranes or causing impaired haemocompatibility. Sieving coefficients for most solutes were independent of volume substitute and flow rate. Haemocompatibility and filter clearance deteriorated after addition of HES200 or GEL to the blood.

CONCLUSIONS

Under standardized in vitro conditions, we found that colloids which reduce cell aggregability cause improved HF- and PF-performance. This phenomenon may provide new options for higher clearances and may lead to new concepts in low dose anticoagulation.

3.5% urea-linked gelatin is as effective as 6% HES 200/0.5 for volume management in cardiac surgery patients

PURPOSE

To compare the efficacy of volume expansion with 3.5% gelatin and 6% hydroxyethyl starch 200/0.5 in patients undergoing cardiac surgery. The second objective was to compare the two colloids in terms of blood losses and allogeneic blood transfusion exposure rate.

METHODS

In this open-label controlled study, patients were randomly allocated to receive either 3.5% urea-linked gelatin (GEL group: n = 55) or 6% hydroxyethyl starch 200/0.5/5.1 (HES group: n = 55) for per- (including priming of the bypass machine) and postoperative volume management with a maximum dosage of 30 +/- 3 mL.kg(-1).day(-1). Volume replacement was guided according to routine per- and postoperative care based on cardiac index, mixed venous oxygen saturation, and diuresis. If additional colloid was required, 4.5% albumin had to be given. The study period comprised per- and postoperative investigations up to 18 hr after surgery.

RESULTS

All hemodynamic variables were comparable in both groups. Total study drug was 25.8 +/- 4.8 mL.kg(-1) in the GEL group and 24.5 +/- 6.0 mL.kg(-1) in the HES group. There was no difference in the number of patients receiving albumin solution or in the amount of albumin administered. Total blood loss was higher in the HES than in the GEL group (11.0 +/- 7.8 mL.kg(-1) vs 8.7 +/- 4.0 mL.kg(-1); P < 0.05) resulting in a higher need for allogeneic blood transfusion (HES: nine patients received 12 units, GEL two patients received 3 units; P = 0.026).

CONCLUSION

In the conditions of the present study, HES was not associated with a better plasma expansion effect than GEL. HES could result in a higher need for allogeneic blood transfusion.

Perioperative fluid volume optimization following proximal femoral fracture

BACKGROUND

Proximal Femoral Fracture (PFF) or 'hip fracture' is a frequent injury, and adverse outcomes are common. Several factors suggest the importance of developing techniques to optimize intravascular fluid volume. These may include protocols that enhance the efficacy of clinicians' assessments, invasive techniques such as oesophageal Doppler or central venous pressure monitoring, or advanced non-invasive techniques such as plethysmographic pulse volume determination.

OBJECTIVES

To determine the optimal method of fluid volume optimization for adult patients undergoing surgical repair of PFF. Comparisons of fluid types, of blood transfusion strategies or of pharmacological interventions are not considered in this review.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library, issue 4, 2003), MEDLINE (1985 to 2003), EMBASE (1985 to 2003), and bibliographies of retrieved articles. Relevant journals and conference proceedings were handsearched.

SELECTION CRITERIA

Randomized controlled studies comparing a fluid optimization intervention with normal practice or with another fluid optimization intervention, in patients following PFF undergoing surgery of any type under anaesthesia of any type.

DATA COLLECTION AND ANALYSIS

Searches and exclusion of clearly irrelevant articles were performed by one reviewer. Two reviewers examined independently the remaining studies, extracting study quality and results data. A wide range of short- and long-term outcome data were sought. Studies were excluded if they did not meet selection criteria or if results were likely to be biased. Due to inconsistent data reporting, combination of data was not generally possible.

MAIN RESULTS

Searches identified four trials, of which two studies, randomizing a total of 130 patients, were of adequate quality and addressed the review question. Both studies were of invasive advanced haemodynamic monitoring, either oesophageal Doppler ultrasonography or central venous pressure monitoring, during the intraoperative period only. In both, invasive monitoring led to significant increases in fluid volumes infused and reductions in length of hospital stay. The pooled Peto odds ratio for in-hospital fatality was 1.44 (95% confidence interval 0.45-4.62). Neither study followed patients beyond hospital discharge or assessed functional outcomes. No serious complications were directly attributable to the interventions. There were no studies of protocol-guided fluid optimization or of advanced non-invasive techniques.

REVIEWER'S CONCLUSIONS

Invasive methods of fluid optimization during surgery may shorten hospital stay, but their effects on other important, patient-centred, longer-term outcomes are uncertain. Adverse effects on fatality cannot be excluded. Other fluid optimization techniques have not been evaluated. The lack of randomized studies of adequate quality addressing this important question is disappointing. More research is needed.