Colloid-induced kidney injury: experimental evidence may help to understand mechanisms

The effects of hydroxyethyl starch 130/0.4 on perioperative renal function in patients undergoing cardiac surgery: A randomised controlled trial

Background

Acute kidney injury (AKI) after cardiac surgery increases the risk of morbidity and mortality. Hydroxyethyl starch (HES) is often used during surgery due to its plasma-volume expanding effect, but the impact of HES 130/0.4 on renal function in patients undergoing cardiac surgery remains unclear. The aim of our study is to investigate the impact of HES 130/0.4 on postoperative renal function in patients undergoing cardiac surgery using cardiopulmonary bypass.

Methods

Our study was a randomised, single-center, single-blind study conducted on 60 adult patients who underwent cardiac surgery using cardiopulmonary bypass: 30 patients were intraoperatively administered with HES 130/0.4; the other 30 with Ringer's bicarbonate. The primary endpoints were occurrence of AKI within 30 days of surgery and the disease stages.

Results

The mean dose of 6% HES 130/0.4 was 28 ml/kg. AKI occurred within 30 days of the operation in 8 cases (28.6%) in the HES group and 6 cases (21.4%) in the crystalloid group (no significance: p = 0.5371). Disease stages were as follows: “no AKI”, “stage 1”, “stage 2″ and “stage 3″, accounting for 20 cases (71.5%), 6 cases (21,4%), 2 cases (7.1%), and 0 cases, respectively, in the HES group, and 22 cases (78.6%), 6 cases (21.4%), 0 cases, and 0 cases, respectively, in the crystalloid group (no significance: p = 0.3508).

Conclusion

There was no significant difference in the occurrences or stages of AKI during the 30 days following cardiac surgery with cardiopulmonary bypass between patients administered with HES 130/0.4 or Ringer's bicarbonate.

•

Hydroxyethyl starch 130/0.4 is an effective plasma-volume expander.

•

Hydroxyethyl starch has a potential renal toxicity in cardiac surgery.

•

Acute kidney injury after cardiac surgery increases the risk of mortality.

•

Administration of hydroxyethyl starch 130/0.4 or crystalloid in cardiac surgery.

•

No difference in the occurrences or stages of acute kidney injury between groups.

Fluid Resuscitation Aggravates the Cellular Injury in a Hemorrhagic Shock Model

<b><i>Background:</i></b> Resuscitation is the initial step for hemorrhagic shock. However, there is still controversy as to which fluid achieves the best results clinically and experimentally. <b><i>Aim:</i></b> It was aimed to investigate the effects of 0.9% NaCl (sodium chloride) and 6% HES (hydroxyethyl starch) on the kidney and blood environment. <b><i>Methods:</i></b> Twenty-four male Wistar rats were assigned as control, shock, and resuscitated (colloid: 6% HES and crystalloid: 0.9% NaCl) groups. Besides hemodynamics (mean arterial pressure and shock index) monitoring and kidney function evaluation, hemolysis, oxidative stress, inflammation, and glycocalyx degradation were evaluated in the plasma and kidney. <b><i>Results:</i></b> (1) Macrohemodynamics were successfully restored by both fluids. (2) Although 3 times more crystalloid volume was applied compared to the colloid resuscitation, similar hematocrit levels were found in both resuscitation strategies (32.8 ± 2.3 vs. 33.3 ± 1.0). (3) NaCl resuscitation led to increases in the hemolytic index, catalytic iron, and sialic acid compared to control, while HES administration increased the levels of malondialdehyde, ischemia-modified albumin, and sialic acid. (4) However, both fluid resuscitation strategies could inhibit inflammation and oxidative stress in the kidney and restore kidney function parameters. <b><i>Conclusion:</i></b> Although both NaCl and HES resuscitation showed protection of the kidney function against oxidative stress and inflammation, these fluids initiated the injury process.

Assessment of Hydroxyethyl Starch (6% HES 130/0.4) Kidney Storage in Critically Ill Dogs: A Post-mortem Prospective Study

Objective: Intravenous hydroxyethyl starch (HES) solutions are potentially nephrotoxic due to rapid renal tissue uptake, subsequent osmotic nephrosis, and long-lasting intracellular storage. This study aimed to investigate the severity of intracellular storage of HES in renal tissue samples from critically ill dogs receiving 6% HES 130/0.4.

Materials and Methods: Fresh, post-mortem (<2 h after death) renal tissue samples were analyzed through histology, immunohistochemistry (HES 130/0.4-specific antibodies), and electron microscopy for the severity of renal tubular vacuolization (VAC), intravacuolar HES accumulation (ACC), and ultra-structure impairment. Moreover, we investigated the relationship between VAC or ACC grade and HES dose (mL/kg), duration of HES administration (h), and pre-HES plasma creatinine concentrations.

Results: Histology revealed that 2/20 dogs (10%) had no, 11/20 dogs (55%) had mild, 5/20 dogs (25%) had moderate, and 2/20 dogs (10%) had severe VAC. Immunohistochemistry revealed that 5/20 dogs (25%) had no, 6/20 dogs (30%) had mild, 7/20 dogs (35%) had moderate, and 2/20 dogs (10%) had severe ACC. Both changes were predominantly found in the distal tubular epithelium of mild and moderate cases, and all tubular segments were affected in severe cases. Seven of 20 dogs (35%) had osmotic nephrosis (ON). On electron microscopy, large granules with an electron-dense content were repeatedly detected in individual cells, mainly in the distal tubules. No correlation was found between cumulative HES dose or duration of HES administration and VAC grade, ACC grade, or presence/absence of ON.

Conclusion: A high percentage of dogs had renal tubular HES storage and one-third of dogs showed HES-induced ON. Short-term HES administration caused VAC and ACC, regardless of the dose or duration of administration. In contrast to previous studies, HES 130/0.4 deposits were mainly located in the renal distal tubule.

Association of Preoperative Prognostic Nutritional Index and Postoperative Acute Kidney Injury in Patients Who Underwent Hepatectomy for Hepatocellular Carcinoma

Various biological indicators are reportedly associated with postoperative acute kidney injury (AKI) in the surgical treatment of hepatocellular carcinoma (HCC). However, only a few studies have evaluated the association between the preoperative prognostic nutritional index (PNI) and postoperative AKI. This study evaluated the association of the preoperative PNI and postoperative AKI in HCC patients. We retrospectively analyzed 817 patients who underwent open hepatectomy between December 2007 and December 2015. Multivariate regression analysis was performed to evaluate the association between the PNI and postoperative AKI. Additionally, we evaluated the association between the PNI and outcomes such as postoperative renal replacement therapy (RRT) and mortality. Cox regression analysis was performed to assess the risk factors for one-year and five-year mortality. In the multivariate analysis, high preoperative PNI was significantly associated with a lower incidence of postoperative AKI (odds ratio (OR): 0.92, 95% confidence interval (CI): 0.85 to 0.99, p = 0.021). Additionally, diabetes mellitus and the use of synthetic colloids were significantly associated with postoperative AKI. PNI was associated with postoperative RRT (OR: 0.76, 95% CI: 0.60 to 0.98, p = 0.032) even after adjusting for other potential confounding variables. In the Cox regression analysis, high PNI was significantly associated with low one-year mortality (Hazard ratio (HR): 0.87, 95% CI: 0.81 to 0.94, p < 0.001), and five-year mortality (HR: 0.93, 95% CI: 0.90–0.97, p < 0.001). High preoperative PNI was significantly associated with a lower incidence of postoperative AKI and low mortality. These results suggest that the preoperative PNI might be a predictor of postoperative AKI and surgical prognosis in HCC patients undergoing open hepatectomy.

Effects of hydroxyethyl starch and gelatin on the risk of acute kidney injury following orthotopic liver transplantation: A multicenter retrospective comparative clinical study

Objectives

This multicenter retrospective study aimed to compare the effects of HES and gelatin (GEL) on the risk of post-OLT AKI.

Method

A total of 1,672 patients undergoing OLT were enrolled from major transplant centers in China between 2005 and 2013. These patients were divided into three groups: GEL, hydroxyethyl starch (HES), and GEL + HES group.

Results

There was no significant difference in the incidence of post-OLT AKI among the GEL, HES, and GEL + HES groups. The GEL + HES group had a lower incidence of stage II post-OLT AKI than the other two groups. Compared with patients receiving GEL, patients receiving HES did not harbor an increased risk of AKI. Our results showed that MELD score (adjusted odds ratio [OR], 1.579; 95% confidence interval [CI], 1.123–2.219; P = 0.009) and preoperative anemia (adjusted OR, 1.533; 95% CI, 1.212–1.939; P < 0.001) were independent risk factors for post-OLT AKI, and normal preoperative Scr level (vs abnormal; adjusted OR, 0.402; 95% CI, 0.222–0.729; P = 0.003) was independent protective factors for post-OLT AKI.

Conclusion

This large-scale multicenter retrospective study found that the intraoperative use of HES did not increase the overall incidence of post-OLT AKI in patients when compared with GEL, and whether to increase the risk of post-OLT AKI needs to be further explored.

Intraoperative Data Enhance the Detection of High-Risk Acute Kidney Injury Patients When Added to a Baseline Prediction Model

BACKGROUND

Aspects of intraoperative management (eg, hypotension) are associated with acute kidney injury (AKI) in noncardiac surgery patients. However, it is unclear if and how the addition of intraoperative data affects a baseline risk prediction model for postoperative AKI.

METHODS

With institutional review board (IRB) approval, an institutional cohort (2005-2015) of inpatient intra-abdominal surgery patients without preoperative AKI was identified. Data from the American College of Surgeons National Surgical Quality Improvement Program (preoperative and procedure data), Anesthesia Information Management System (intraoperative data), and electronic health record (postoperative laboratory data) were linked. The sample was split into derivation/validation (70%/30%) cohorts. AKI was defined as an increase in serum creatinine ≥0.3 mg/dL within 48 hours or >50% within 7 days of surgery. Forward logistic regression fit a baseline model incorporating preoperative variables and surgical procedure. Forward logistic regression fit a second model incorporating the previously selected baseline variables, as well as additional intraoperative variables. Intraoperative variables reflected the following aspects of intraoperative management: anesthetics, beta-blockers, blood pressure, diuretics, fluids, operative time, opioids, and vasopressors. The baseline and intraoperative models were evaluated based on statistical significance and discriminative ability (c-statistic). The risk threshold equalizing sensitivity and specificity in the intraoperative model was identified.

RESULTS

Of 2691 patients in the derivation cohort, 234 (8.7%) developed AKI. The baseline model had c-statistic 0.77 (95% confidence interval [CI], 0.74-0.80). The additional variables added to the intraoperative model were significantly associated with AKI (P < .0001) and the intraoperative model had c-statistic 0.81 (95% CI, 0.78-0.83). Sensitivity and specificity were equalized at a risk threshold of 9.0% in the intraoperative model. At this threshold, the baseline model had sensitivity and specificity of 71% (95% CI, 65-76) and 69% (95% CI, 67-70), respectively, and the intraoperative model had sensitivity and specificity of 74% (95% CI, 69-80) and 74% (95% CI, 73-76), respectively. The high-risk group had an AKI risk of 18% (95% CI, 15-20) in the baseline model and 22% (95% CI, 19-25) in the intraoperative model.

CONCLUSIONS

Intraoperative data, when added to a baseline risk prediction model for postoperative AKI in intra-abdominal surgery patients, improves the performance of the model.

Hydroxyethyl Starch 6% 130/0.4 in a Balanced Electrolyte Solution and Renal Function After Nephrectomy

BACKGROUND

Although previous studies have reported nephrotoxicity associated with hydroxyethyl starch (HES), the long-term effect of HES on renal function after nephrectomy has rarely been reported. We evaluated the association between intraoperative HES administration and short- and long-term renal function after nephrectomy.

METHODS

We retrospectively reviewed 1106 patients who underwent partial or radical nephrectomy. The patients were divided into 2 groups: patients who received (HES group) or did not receive 6% HES 130/0.4 intraoperatively (non-HES group). The primary outcome was new-onset chronic kidney disease (CKD) stage 3a (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m) or higher or all-cause mortality during 60 months after surgery. Propensity score matching was performed to address baseline differences between the 2 groups. Renal survival determined by stage 3a and stage 5 CKD (eGFR <15 mL/min/1.73 m) or all-cause mortality were compared up to 60 months before and after matching. We compared postoperative acute kidney injury (AKI) and CKD upstaging in the matched cohort as secondary outcomes. Ordinal logistic regression and Cox proportional hazards regression analyses using inverse probability of treatment weighting were performed for postoperative AKI and our primary outcome, respectively. A subgroup analysis of partial nephrectomy was performed.

RESULTS

Thirty percent of patients received HES intraoperatively. Balanced solution and 0.9% normal saline was administered during surgery in both groups. Renal survival was not significantly different between groups after matching (log-rank test P = .377 for our primary outcome, and P = .981 for stage 5 or all-cause mortality, respectively). In the matched cohort (HES group: n = 280, non-HES group: n = 280), the incidence of AKI or CKD upstaging at 1 year was not significantly different (AKI: n = 94, 33.6% in HES group versus n = 90, 32.1% in non-HES group; CKD upstaging: n = 132, 47.1% in HES group versus n = 122, 43.6% in non-HES group; odds ratio [OR], 1.16; 95% confidence interval [CI], 0.83-1.61; P = .396). Intraoperative HES administration was not associated with postoperative renal outcomes (AKI: OR, 0.97; 95% CI, 0.81-1.16; P = .723; CKD stage 3a or higher or all-cause mortality: hazard ratio, 1.01; 95% CI, 0.89-1.14; P = .920). Subgroup analysis yielded similar results.

CONCLUSIONS

Intraoperative 6% HES 130/0.4 administration was not significantly associated with short- and long-term renal function or renal survival up to 5 years in patients undergoing partial or radical nephrectomy. However, wide CI including large harm effect precludes firm conclusion and inadequate assessment of safety cannot be ruled out by our results.

Large volume infusions of hydroxyethyl starch during cardiothoracic surgery may be associated with postoperative kidney injury: propensity-matched analysis

Background

The safety of intraoperative administration of hydroxyethyl starch (HES) has been debated. We hypothesized that intraoperative use of HES is associated with postoperative acute kidney injury (AKI) following cardiopulmonary bypass (CPB).

Materials and methods

Patients who underwent cardiothoracic surgery using CPB between 2007 and 2014 were retrospectively reviewed. The incidence of AKI within 7 days after surgery, defined by the Kidney Disease Improving Global Outcome criteria, was compared for patients who did or did not receive 6% (70/0.5) or 6% (130/0.4) HES for anesthesia management before or after CPB. Multivariable logistic regression and propensity matching analysis were performed to examine whether use of HES is associated with postoperative AKI. Outcomes comparing patients receiving HES ≥ 1000 mL and < 1000 mL were also compared.

Results

Data from 1976 patients were reviewed. All patients received 70/0.5 HES as a part of the priming solution for CPB. The incidence of postoperative AKI was 28.2% in patients who received HES and 26.0% in patients who did not (p = 0.33). In multivariable analysis, there was no correlation between the use of HES and the incidence of AKI (odds ratio 0.87, 95% CI 0.30–2.58, p = 0.81). Propensity matching showed that the incidence of AKI was not significantly different between 481 patients administered with HES and 962 patients (26.6% vs. 26.9%, p = 0.95) who did not receive HES for anesthesia management. However, peak creatinine levels, needed for renal replacement therapy, and in-hospital mortality were higher, and 28-day hospital-free days were lower in patients receiving HES ≥ 1000 mL than those receiving HES < 1000 mL (p < 0.05).

Conclusions

Intraoperative use of HES was not associated with postoperative AKI following CPB. However, administration of large volumes of HES may be associated with kidney-related adverse clinical outcomes.

Does the choice of intraoperative fluid modify abdominal aneurysm repair outcomes?: A cohort analysis

Intraoperatively administered hydroxyethyl starch could be a risk indicator for postoperative acute kidney injury (AKI) in vascular surgical patients.In a single-center retrospective cohort analysis, we assessed the impact of hydroxyethyl starch and other risk indicators on AKI and mortality in 1095 patients undergoing elective open abdominal aneurysm repair (AAA-OR) or endovascular aortic repair (EVAR). We established logistic regression models to determine the effect of various risk indicators, including hydroxyethyl starch, on AKI, as well as Cox proportional hazard models to assess the effect on mortality.The use of intravenous hydroxyethyl starch was not associated with an increased risk of AKI or mortality. Patients undergoing EVAR were less likely to develop AKI (4% vs 18%). Multivariate risk indicators associated for AKI included suprarenal or pararenal aortic cross-clamp [odds ratio (OR), 4.44; 95% confidence interval (95% CI), 2.538-7.784; P < .001] and procedure length (OR, 1.005; 95% CI, 1.003-1.007; P < .001), and favored EVAR (OR, 0.351; 95% CI, 0.118-0.654; P < .01). Main multivariate risk indicators associated with mortality included patients needing an urgent procedure [hazard ratio (HR), 2.294; 95% CI, 1.541-3.413; P < .001], those with suprarenal or pararenal aortic cross-clamp (HR, 1.756; 95% CI, 1.247-2.472; P < .01), and patients undergoing EVAR (HR, 1.654; 95% CI, 1.292-2.118; P < .001).We found neither a benefit nor a negative effect of hydroxyethyl starch on the risk of AKI or mortality. Instead, other variables and comorbidities were found to be relevant for the development of postoperative AKI and survival. Nevertheless, clinicians should be aware of the high risk of postoperative AKI, particularly among those undergoing AAA-OR procedures.

Hydroxyethyl starches in equine medicine

OBJECTIVE

To review and discuss the use of hydroxyethyl starches (HES) in equine veterinary medicine, and to provide recommendations for its use.

DATA SOURCES

Veterinary and human peer-reviewed medical literature including scientific reviews, meta-analyses, and original research articles.

HUMAN DATA SYNTHESIS

Increasing evidences on adverse effects after HES use and decreasing support for beneficial effects with regards to volume expansion and colloid osmotic pressure (COP) support in critically ill subjects have led to a recent guideline to limit the use of HES in critically ill people.

EQUINE VETERINARY DATA SYNTHESIS

The rationale for HES use in horses is mainly extrapolated from human medicine, and very limited studies in horses are available. There is limited evidence suggesting a superiority of volume expansion effects of HES over crystalloids. The potential for HES to increase and maintain COP is well supported, but there is no evidence that maintaining or increasing plasma COP influences outcome, tissue edema formation, or rates of complications that potentially relate to edema formation. HES induce dose-dependent changes in coagulopathic parameters, but there is no evidence that HES causes clinical coagulopathies. Insufficient data are available on other adverse effects such as acute kidney injury, or mortality in horses. The use of HES should be restricted in septic patients, but may still have some use in cases of hemorrhagic shock resuscitation, hypoalbuminemia, or perioperative fluid replacement.

CONCLUSION

The evidence supporting the use of HES in horses is weak due to lack of species-specific investigations. Acknowledging species differences, the use of HES should be judicious, yet with some recognition of its benefits in particular cases. More research is necessary to improve knowledge on use of HES in horses and to establish better future recommendations.

Understanding the Harms of HES: A Review of the Evidence to Date

Intravenous (IV) fluid resuscitation is one of the most common interventions in intensive care medicine. Despite clear guidelines, the choice of IV fluid is largely dependent on physician preference instead of high-quality evidence of efficacy and safety. This is particularly the case for synthetic colloids, such as hydroxyethyl starch (HES). The use of HES in critical care has been associated with increased rates of acute kidney injury (AKI), renal replacement therapy and mortality. In light of this, current guidelines and scientific and regulatory bodies do not recommend the use of HES for fluid therapy in critical illness and caution against its use in many other settings. Despite this, HES products are still debated and used. Awareness of the indications, contraindications, doses, benefits and adverse effects for IV fluids, as well as recommendations from scientific and regulatory bodies, is essential to guarantee patients' safety. Poor awareness of optimal IV fluid therapy has recently been revealed in some countries including Turkey. Therefore, we provide a review of fluids used for resuscitation, discuss safety data and adverse effects of HES, such as increased AKI and mortality, and discuss recent updates from scientific and regulatory bodies in order to raise awareness of fluid therapy. We conclude that given the lack of a clear benefit of HES in any clinical setting and the availability of safer alternatives, such as crystalloids and albumin, HES should be avoided.

Effects of hydroxyethyl starch 130/0.4 on the kidney tissue of rats with ureteral obstruction

Objective

This study was conducted since the effects of colloid solutions on the renal system remain controversial and need to be adequately studied in animals. We aimed to evaluate the effects of hydroxyethyl starch (Voluven) on the kidney tissue of rats with late renal failure due to ureteral obstruction.

Materials and methods

Rats were divided into four groups: Group C, control; Group HES, hydroxyethyl starch solution (HES) 130/0.4 (Voluven^®); Group UUO, unilateral ureteral obstruction (UUO); and Group UUO-HES, UUO-HES 130/0.4 (Voluven^®). In the groups with ureteral obstruction, the distal part of the right ureter was accessed and sutured through a lower abdominal incision under ketamine anesthesia. Any signs of late-stage renal failure were evaluated after three weeks. Rats in the HES group and the renal failure-HES group were administered with HES 130/0.4 as a single intravenous dose of 20 mL/kg. After a follow-up of 24 hours, intra-abdominal blood sample was collected, and the rats were sacrificed. Biochemical and histopathological parameters were then evaluated.

Results

Ureteral obstruction significantly increased urea and creatinine levels. In addition, when the UUO-HES and HES groups were compared, the administration of HES increased urea and creatinine levels in the UUO-HES group. Nitric oxide enzyme activity and malondialdehyde levels have significantly increased in the UUO groups. In addition, HES significantly increased nitric oxide activity and malondialdehyde levels in the UUO-HES group, in comparison with the HES group. The activity of caspases 3 and 8 was significantly increased in the UUO groups. In addition, HES significantly increased the activity of caspases 3 and 8 in the UUO-HES group, in comparison with the HES group. Light microscopy revealed significant changes in the UUO groups, especially in the obstructed kidneys.

Conclusion

If indicated, HES should be used with caution in cases of UUO, but not in the cases of bilateral ureteral obstruction. Other aspects of these findings, including the clinical significance and practical applications, merit further experimental and clinical investigation.

Relationship between perioperative thyroid function and acute kidney injury after thyroidectomy

Thyroid dysfunction may alter kidney function via direct renal effects and systemic haemodynamic effects, but information on the effect of thyroid function on postoperative acute kidney injury (AKI) following thyroidectomy remains scarce. We reviewed the medical records of 486 patients who underwent thyroidectomy between January 2010 and December 2014. Thyroid function was evaluated based on the free thyroxine or thyroid stimulating hormone levels. The presence of postoperative AKI was determined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. AKI developed in 24 (4.9%) patients after thyroidectomy. There was no association between preoperative thyroid function and postoperative AKI. Patients with postoperative hypothyroidism showed a higher incidence of AKI than patients with normal thyroid function or hyperthyroidism (19.4%, 6.7%, and 0%, respectively; P = 0.044). Multivariable logistic regression analysis showed that male sex (OR, 4.45; 95% CI, 1.80-11.82; P = 0.002), preoperative use of beta-blockers (OR, 4.81; 95% CI, 1.24-16.50; P = 0.016), low preoperative serum albumin levels (OR, 0.29; 95% CI, 0.11-0.76; P = 0.011), and colloid administration (OR, 5.18; 95% CI, 1.42-18.15; P = 0.011) were associated with postoperative AKI. Our results showed that postoperative hypothyroidism might increase the incidence of AKI after thyroidectomy.

Balanced 10% hydroxyethyl starch compared with balanced 6% hydroxyethyl starch and balanced crystalloid using a goal-directed hemodynamic algorithm in pancreatic surgery: A randomized clinical trial

BACKGROUND

While hydroxyethyl starch (HES) solutions are not recommended any longer in critically ill patients, data on efficacy and safety during surgery are still limited.

METHODS

In a randomized controlled trial 63 patients were assigned to receive 10% HES (130/0.42), 6% HES (130/0.42), or crystalloid within a goal-directed hemodynamic algorithm during pancreatic surgery. The primary endpoints were intraoperative volume of HES and time until fully on oral diet.

RESULTS

The trial was terminated early upon recommendation of an independent data monitoring committee due to futility for efficacy at a planned interim analysis. The intraoperative volume of HES was not different between 10% and 6% HES group (2000 [1500; 2250] vs 2250 [1750; 3000] mL, P=.059). However, considering an inhomogeneity of patient's body weight between HES groups, there was a significant difference in intraoperative volume of HES between 10% and 6% group after adjusting for patient's body weight (24.0 [21.6; 28.3] vs 33.3 [28.2; 46.2] mL kg BW, P = .002). Patients in the HES groups required less additional fluid after dose limit than those in the crystalloid group, resulting in lower intraoperative net balances. The time until fully on oral diet was not different between all study groups. Applying KDIGO oliguria criterion, patients receiving 10% HES had more AKI compared to patients receiving crystalloids (86.7 vs 45.0%, P = .010), whereas those receiving 6% HES and crystalloids did not differ (58.8 vs 45.0%, P = .253). Further explorative analyses using a gray-zone approach indicated that patients receiving 6% HES below 18.8 mL kg will not experience AKI with near certainty.

CONCLUSIONS

After adjusting for patient's body weight, patients receiving 6% HES required more volume of HES than patients receiving 10% HES. The relation of 140% represents very well the volume effect of a hyperoncotic 10% HES solution. Nonetheless, both HES solutions were similarly effective in reducing intraoperative fluid administration compared with crystalloid, but this did not result into differences in gastrointestinal outcomes. Patients receiving 10% HES showed an increased rate of AKI, whereas those receiving 6% HES and crystalloid did not differ. However, 6% HES should not be applied beyond 18 mL kg during surgery.

Effect of tetrastarch (hydroxyethyl starch 130/0.4) on plasma creatinine concentration in cats: a retrospective analysis (2010-2015)

Objectives The objective was to determine survival and changes in creatinine concentrations after administration of 6% tetrastarch (hydroxyethyl starch [HES] 130/0.4) vs crystalloids in critically ill cats. Methods The medical records were reviewed for cats admitted to the intensive care unit with at least two plasma creatinine measurements and initial concentrations not exceeding the upper reference interval. Cats were excluded if they had received HES prior to admission or if they had received fluid therapy for <24 h between initial and subsequent measurements. Changes in creatinine concentrations were evaluated as the percentage change from initial values to the maximum subsequent measurements. Cats receiving only crystalloids were assigned to the crystalloid group; cats receiving only HES or HES and crystalloids were assigned to the HES group. Results Ninety-three cats were included in the study (62 in the crystalloid group, 31 in the HES group). The total median cumulative HES dose was 94 ml/kg (range 26-422 ml/kg) and 24 ml/kg/day (range 16-42 ml/kg/day). No difference was detected between the groups for age, sex, body weight or mortality. The HES group had a significantly longer length of hospitalisation ( P = 0.012), lower albumin concentrations ( P <0.001), higher Acute Patient Physiologic and Laboratory Evaluation scores ( P = 0.037) and higher incidence of systemic inflammatory response syndrome ( P = 0.009) and sepsis ( P = 0.013). There was no significant difference in initial, maximum or maximum change in creatinine concentrations between the groups. Moreover, there was no significant difference in maximum change in creatinine concentrations in the subgroups of cats with systemic inflammatory response syndrome or sepsis. Conclusions and relevance In this population of cats, the administration of HES did not result in a significantly greater increase in creatinine from values measured on admission or higher mortality compared with administration of crystalloids. Further prospective studies are needed to assess both safety and efficacy of HES in cats before recommendations can be made.

Rapid exacerbation of renal function after administration of hydroxyethyl starch in a dog

Hydroxyethyl starches (HES) are commonly used synthetic colloidal solution in veterinary medicine. Despite of possible adverse effect to kidney injury in human, there is no report about nephrotoxic effects of HES in dogs. HES was administered to a Golden retriever (4-year-old, intact male) with ascites in order to increase plasma osmolality. Initially, the dog was mild azotemic, however, kidney function was rapidly deteriorated after several days of HES administration. Finally, histopathological examination revealed remarkable osmotic nephrosis. In the case reported herein, acute kidney injury was remarkably developed after HES administration. Clinical and histopathologic findings of acute kidney injury support nephrotoxic effects of HES to a dog.

Is Brain-Dead Donor Fluid Therapy With Colloids Associated With Better Kidney Grafts?

OBJECTIVES

Fluid therapy is required to maintain perfusion to donor organs. Recent reviews on the choices of fluids have emphasized the safety of using crystalloids, as opposed to fluid therapy with colloids, which has been reported to be either unequivocally or potentially harmful in a number of studies on various patient populations. We aimed to analyze whether the type of fluid administered to donors is connected with kidney transplant outcomes.

MATERIALS AND METHODS

A total of 100 consecutive brain-dead multiorgan donors and their respective 181 kidney recipients were studied retrospectively. Data concerning donor fluid therapy, the characteristics of the donors and the recipients, and outcomes after kidney transplant were extracted from organ retrieval and patient records. Cases with early graft function were compared with cases with delayed graft function.

RESULTS

Donors had received both crystalloids and colloids in most cases (84%). Fluid therapy with crystalloids alone was more common among the 40 recipients with delayed (30%) than in the 103 recipients with early graft function (11%) (P = .005). Donor age, time on renal replacement therapy before transplant, and donor fluid therapy with crystalloids alone were independent risk factors for delayed graft function in multivariate analysis.

CONCLUSIONS

Our results suggest that donor fluid therapy including colloids could be beneficial instead of harmful compared with treatment with crystalloids alone. This finding needs to be evaluated in prospective studies.

Effect of Hydroxyethyl Starch on Acute Kidney Injury After Living Donor Hepatectomy

BACKGROUND

Concerns about the adverse effects of hydroxyethyl starch (HES) on renal function have been raised in recent studies involving critically ill patients. We aimed to evaluate the effect of HES on acute kidney injury (AKI) after living donor right hepatectomy.

METHODS

We performed a 1:3 propensity score matching analysis of the medical records of 1641 living donors who underwent a donor right hepatectomy. They were divided into the control group (n = 60), who received only crystalloids, and the colloid group (n = 1,581), who received HES 130/0.4 and crystalloids. Postoperative AKI was determined by AKI Network (AKIN) and Risk, Injury, Failure, Loss, End-stage (RIFLE) criteria.

RESULTS

A 1:3 propensity score matching was performed in 206 donors, 54 donors in the control group and 152 donors in the colloid group. For the matched colloid group, the median amount of 7.65 mL/kg (interquartile range, 6.64-9.20) of colloid and 58.19 mL/kg (interquartile range, 45.63-71.51) of crystalloid were given. The median amount of administered crystalloid in the control group was 56.48 mL/kg (interquartile range, 47.94-76.12) after propensity score matching. The incidences of AKI were not different between the control and colloid groups (P = .460 by AKIN criteria; P = .999 by RIFLE criteria).

CONCLUSION

Intraoperative administration of HES may not be associated with AKI after living donor hepatectomy. This result can provide useful information on perioperative fluid management in living liver donors.

Retrospective evaluation of the effects of administration of tetrastarch (hydroxyethyl starch 130/0.4) on plasma creatinine concentration in dogs (2010-2013): 201 dogs

OBJECTIVE

To determine changes in creatinine concentrations following the administration of 6% tetrastarch (hydroxyethyl starch [HES] 130/0.4) compared to crystalloids (CRYSs) in critically ill dogs.

DESIGN

Retrospective case series (2010-2013).

SETTING

University teaching hospital.

ANIMALS

Two hundred and one dogs admitted to the intensive care unit with initial plasma creatinine concentrations not exceeding laboratory reference intervals (52-117 μmol/L [0.6-1.3 mg/dL]) and receiving either CRYSs alone (CRYS group, n = 115) or HES with or without CRYSs (HES group, n = 86) for at least 24 hours.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Creatinine concentrations at admission to the intensive care unit (T0), and 2-13 days (T1) and 2-12 weeks (T2) after initiation of fluid therapy were analyzed. Creatinine concentrations were analyzed as absolute values and as the maximum percentage change from T0 to T1 (T1max%) and from T0 to T2 (T2max%), respectively. Creatinine concentrations were available for 192 dogs during T1 and 37 dogs during T2. The median cumulative dose of HES was 86 mL/kg (range, 12-336 mL/kg). No difference was detected between the groups for age, gender, body weight, and length of hospitalization. Outcome was significantly different between the HES (66% survived) and the CRYS (87% survived) groups (P = 0.014). No significant difference was detected between groups for creatinine concentrations at T0, T1, T2, T1max%, or T2max%. No significant difference was detected between the groups for T1max% creatinine in dogs subclassified as having systemic inflammatory response syndrome or sepsis.

CONCLUSIONS

HES administration in this canine population did not result in increased creatinine concentrations compared to administration of CRYSs. Further studies are needed to establish the safety of HES in critically ill dogs.

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

OBJECTIVES

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

DATA SOURCES

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

HUMAN DATA SYNTHESIS

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

VETERINARY DATA SYNTHESIS

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

CONCLUSIONS

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

Acute Kidney Injury in Cardiac Surgery and Cardiac Intensive Care

Acute kidney injury (AKI) is a serious postoperative complication following cardiac surgery. Despite the incidence of AKI requiring temporary renal replacement therapy being low, it is nonetheless associated with high morbidity and mortality. Therefore, preventing AKI associated with cardiac surgery can dramatically improve outcomes in these patients. The pathogenesis of AKI is multifactorial and many attempts to prevent or treat renal injury have been met with limited success. In this article, we will discuss the incidence and risk factors for cardiac surgery associated AKI, including the pathophysiology, potential biomarkers of injury, and treatment modalities.

Effect of hydroxyethyl starch on postoperative kidney function in patients having noncardiac surgery

BACKGROUND

Whether intraoperative use of hydroxyethyl starch impairs kidney function remains unknown. The authors thus tested the primary hypothesis that Hextend promotes renal injury in surgical patients. Secondarily, the authors evaluated the dose-outcome relationship, in-hospital and 90-day mortality, and whether the relationship between colloid use and acute kidney injury (AKI) depends on baseline risk for AKI.

METHODS

The authors evaluated the data of 44,176 adults without preexisting kidney failure who had inpatient noncardiac surgery from 2005 to 2012. Patients given a combination of colloid and crystalloid were propensity matched on morphometric, and baseline characteristics to patients given only crystalloid. The primary analysis was a proportional odds logistic regression with AKI as an ordinal outcome based on the Acute Kidney Injury Network classification.

RESULTS

The authors matched 14,680 patients receiving colloids with 14,680 patients receiving noncolloids for a total of 29,360 patients. After controlling for potential confounding variables, the odds of developing a more serious level of AKI with Hextend was 21% (6 to 38%) greater than with crystalloid only (P = 0.001). AKI risk increased as a function of colloid volume (P < 0.001). In contrast, the relationship between colloid use and AKI did not differ on baseline AKI risk (P = 0.84). There was no association between colloid use and risk of in-hospital (P = 0.81) or 90-day (P = 0.02) mortality.

CONCLUSION

Dose-dependent renal toxicity associated with Hextend in patients having noncardiac surgery is consistent with randomized trials in critical care patients.

Colloids in sepsis: evenly distributed molecules surrounded by uneven questions

Colloids are frequently used for fluid expansion in the intensive care unit, although its use on several clinical scenarios remains unproven of any relevant clinical benefit. The purpose of this article was to carry out a narrative review regarding the safety and efficacy of colloids in patients with sepsis and septic shock, with emphasis on the most commonly used colloids, albumin and starches. Colloids are effective fluid expanders and are able to restore the hemodynamic profile with less total volume than crystalloids. These properties appear to be preserved even in patients with sepsis with increased capillary permeability. However, some colloids are associated with renal impairment and coagulation abnormalities. Starch use was associated with increased mortality in two large clinical trials. Also, starches probably have significant renal adverse effects and may be related to more need for renal replacement therapy in severe sepsis. Albumin is the only colloid that has been shown safe in patients with sepsis and that may be associated with improved outcomes on specific subpopulations. No trial so far found any robust clinical end point favoring colloid use in patients with sepsis. Because there is no proven benefit of the use of most colloids in patients with sepsis, its use should not be encouraged outside clinical trials. Albumin is the only colloid solution that has proven to be safe, and its use may be considered on hypoalbuminemic patients with sepsis. Nevertheless, there are no robust data to recommend routine albumin administration in sepsis. Starch use should be avoided in patients with sepsis because of the recent findings of a multicenter randomized study until further evidence is available.

Fluid administration and the kidney

PURPOSE OF REVIEW

Intravenous fluids are widely administered in the ICU with the intention of preventing or ameliorating acute kidney injury (AKI). This review focuses on recent studies examining fluid administration and renal function in critical illness to critically examine conventional justifications for fluid administration.

RECENT FINDINGS

Early, targeted, resuscitation of inadequate cardiac output in shock may have a beneficial effect on organ function and patient outcome. However, experimental evidence suggests the relationship between fluid administration and an increase in renal oxygen delivery is weak, whereas any beneficial effects from fluid administration can be short lived. Conversely, evidence associating fluid overload and adverse outcomes is strengthening, whereas more restrictive fluid administration does not seem to predispose to clinically significant AKI in many situations. Furthermore, concerns persist that some colloid or high chloride concentration solutions may directly impair renal function independent of volume overload.

SUMMARY

Adequate volume resuscitation remains a cornerstone to the emergent treatment of critical illness. However, continued fluid administration and positive fluid balances have not been shown to improve renal outcomes and may worsen overall prognosis in AKI. Concerns about renal dysfunction should not deter clinicians from adopting more restrictive approaches to fluid administration.

Are renal adverse effects of hydroxyethyl starches merely a consequence of their incorrect use?

BACKGROUND

Clinical studies such as VISEP-study, which show a negative outcome after the administration of hydroxyethyl starch (HES), are often criticized for an "incorrect" use of HES. It is argued that HES used in these studies differed from usual practice and that recommendations for maximal dosage, duration, and creatinine values were ignored, not enough "free water" was provided and more modern HES solutions should have been used. These comments imply that renal adverse events in clinical studies are the consequence of an inappropriate use of HES. We therefore searched for evidence whether these suggested measures are beneficial.

METHODS

Narrative review; post hoc statistical analysis of epidemiologic data from a representative nationwide survey.

RESULTS

It is evident from published clinical studies that the renal risk of HES increases with cumulative dose and rising serum creatinine values, but no safe upper dose limit or creatinine threshold is known. Suggested safety measures were not able to prevent HES-induced renal failure in clinical studies. Published clinical trials with modern HES solutions are not suited to prove its assumed increased safety because of small sample sizes, low cumulative doses, short observation periods, and inadequate control fluids. Use of HES in a clinical study with negative outcomes conformed to clinical practice, indicating the generalizability of study results.

CONCLUSION

There is no evidence for the assumption that HES-associated renal impairment may be avoided by accompanying measures. Because HES use does not improve clinical outcome, the question arises whether it should be used at all in patients at risk.

The efficacy and safety of colloid resuscitation in the critically ill

Despite evidence from clinical studies and meta-analyses that resuscitation with colloids or crystalloids is equally effective in critically ill patients, and despite reports from high-quality clinical trials and meta-analyses regarding nephrotoxic effects, increased risk of bleeding, and a trend toward higher mortality in these patients after the use of hydroxyethyl starch (HES) solutions, colloids remain popular and the use of HES solutions is increasing worldwide. We investigated the major rationales for colloid use, namely that colloids are more effective plasma expanders than crystalloids, that synthetic colloids are as safe as albumin, that HES solutions have the best risk/benefit profile among the synthetic colloids, and that the third-generation HES 130/0.4 has fewer adverse effects than older starches. Evidence from clinical studies shows that comparable resuscitation is achieved with considerably less crystalloid volumes than frequently suggested, namely, <2-fold the volume of colloids. Albumin is safe in intensive care unit patients except in patients with closed head injury. All synthetic colloids, namely, dextran, gelatin, and HES have dose-related side effects, which are coagulopathy, renal failure, and tissue storage. In patients with severe sepsis, higher doses of HES may be associated with excess mortality. The assumption that third-generation HES 130/0.4 has fewer adverse effects is yet unproven. Clinical trials on HES 130/0.4 have notable shortcomings. Mostly, they were not performed in intensive care unit or emergency department patients, had short observation periods of 24 to 48 hours, used cumulative doses below 1 daily dose limit (50 mL/kg), and used unsuitable control fluids such as other HES solutions or gelatins. In conclusion, the preferred use of colloidal solutions for resuscitation of patients with acute hypovolemia is based on rationales that are not supported by clinical evidence. Synthetic colloids are not superior in critically ill adults and children but must be considered harmful depending on the cumulative dose administered. Safe threshold doses need to be determined in studies in high-risk patients and observation periods of 90 days. Such studies on HES 130/0.4 are still lacking despite its widespread and increasing use. Because there are safer and equally effective alternatives in the form of crystalloids, use of synthetic colloids should be avoided except in the context of clinical studies.

Year in review 2009: Critical Care--shock

The research papers on shock that have been published in Critical Care throughout 2009 are related to four major subjects: first, alterations of heart function and, second, the role of the sympathetic central nervous system during sepsis; third, the impact of hemodynamic support using vasopressin or its synthetic analog terlipressin, and different types of fluid resuscitation; as well as, fourth, experimental studies on the treatment of acute respiratory distress syndrome. The present review summarizes the key results of these studies together with a brief discussion in the context of the relevant scientific and clinical background published both in this and other journals.