Effect of balanced crystalloids versus saline on urinary biomarkers of acute kidney injury in critically ill adults

Heterogeneity in the definition of major adverse kidney events: a scoping review

Acute kidney injury (AKI) is associated with persistent renal dysfunction, the receipt of dialysis, dialysis dependence, and mortality. Accordingly, the concept of major adverse kidney events (MAKE) has been adopted as an endpoint for assessing the impact of AKI. However, applied criteria or observation periods for operationalizing MAKE appear to vary across studies. To evaluate this heterogeneity for MAKE evaluation, we performed a systematic scoping review of studies that employed MAKE as an AKI endpoint. Four major academic databases were searched, and we identified 122 studies with increasing numbers over time. We found marked heterogeneity in applied criteria and observation periods for MAKE across these studies, with some even lacking a description of criteria. Moreover, 13 different observation periods were employed, with 30 days and 90 days as the most common. Persistent renal dysfunction was evaluated by estimated glomerular filtration rate (34%) or serum creatinine concentration (48%); however, 37 different definitions for this component were employed in terms of parameters, cut-off criteria, and assessment periods. The definition for the dialysis component also showed significant heterogeneity regarding assessment periods and duration of dialysis requirement (chronic vs temporary). Finally, MAKE rates could vary by 7% [interquartile range: 1.7-16.7%] with different observation periods or by 36.4% with different dialysis component definitions. Our findings revealed marked heterogeneity in MAKE definitions, particularly regarding component assessment and observation periods. Dedicated discussion is needed to establish uniform and acceptable standards to operationalize MAKE in terms of selection and applied criteria of components, observation period, and reporting criteria for future trials on AKI and related conditions.

Comparison of the efficacy of 0.9% normal saline with balanced crystalloid (Plasmalyte) in maintaining the metabolic profile in head injury patients undergoing evacuation of acute subdural haematoma - A randomised controlled trial

Background and Aims

The choice of intravenous fluids is important in patients with traumatic brain injury (TBI), where large volumes may be required for resuscitation. Our study aimed to compare 0.9% normal saline (NS) with balanced crystalloid (Plasmalyte) in TBI patients in terms of metabolic and coagulation profile, brain relaxation score (BRS) and renal functions using serum urea, creatinine and urinary tissue inhibitor of metalloproteinases-2* insulin-like growth factor binding protein-7, [TIMP-2]*[IGFBP7], value to assess the risk of acute kidney injury.

Methods

This randomised controlled trial on 90 TBI patients undergoing emergency craniotomy and subdural haematoma evacuation was conducted in a tertiary care institute. The patients were randomised to receive either NS (Group NS) or Plasmalyte (Group P) as the intraoperative maintenance fluid. The primary outcome measures included the potential of hydrogen (pH), base excess (BE) and chloride values from an arterial blood gas. The secondary outcomes were the coagulation profile, BRS and urinary [TIMP-2]*[IGFBP7]. The two groups' metabolic profile differences were analysed using two-way repeated analysis of variance. BRS was analysed using the Mann-Whitney U test. A P value < 0.05 was considered to be statistically significant.

Results

The pH and chloride values were significantly higher, and the BE values were significantly lower in Group P compared to Group NS (P < 0.001). Brain relaxation and coagulation profiles were comparable between the two groups. Serum creatinine (P = 0.002) and urinary [TIMP-2]*[IGFBP7] (P = 0.042) were significantly higher in the NS group.

Conclusion

Plasmalyte maintains a more favourable metabolic profile than NS in TBI patients without affecting brain relaxation adversely.

New Insights into the Fluid Management in Patients with Septic Shock

The importance of fluid resuscitation therapy during the early stages of sepsis management is a well-established principle. Current Surviving Sepsis Campaign (SSC) guidelines recommend the early administration of intravenous crystalloid fluids for sepsis-related hypotension or hyperlactatemia due to tissue hypoperfusion, within the first 3 h of resuscitation and suggest using balanced solutions (BSs) instead of normal saline (NS) for the management of patients with sepsis or septic shock. Studies comparing BS versus NS administration in septic patients have demonstrated that BSs are associated with better outcomes including decreased mortality. After initial resuscitation, fluid administration has to be judicious in order to avoid fluid overload, which has been associated with increased mortality, prolonged mechanical ventilation, and worsening of acute kidney injury. The "one size fits all" approach may be "convenient" but it should be avoided. Personalized fluid management, based on patient-specific hemodynamic indices, provides the foundations for better patient outcomes in the future. Although there is a consensus on the need for adequate fluid therapy in sepsis, the type, the amount of administered fluids, and the ideal fluid resuscitation strategy remain elusive. Well-designed large randomized controlled trials are certainly needed to compare fluid choices specifically in the septic patient, as there is currently limited evidence of low quality. This review aims to summarize the physiologic principles and current scientific evidence regarding fluid management in patients with sepsis, as well as to provide a comprehensive overview of the latest data on the optimal fluid administration strategy in sepsis.

Comparison and evaluation of two different crystalloids - Normal saline and plasmalyte in patients of traumatic brain injury undergoing craniotomy

BACKGROUND AND AIMS

Fluid therapy is one of the most important components of the management of patients with traumatic brain injury (TBI). The present study was planned to compare plasmalyte and normal saline (NS) in patients who underwent craniotomies for TBI in terms of their effects on acid-base equilibrium, renal functions, and coagulation profile.

METHODS

Fifty patients of age 18-45 years of either sex, who underwent emergency craniotomy for TBI, were included in the study. The patients were randomized into two groups. Group P (n = 25) received isotonic balanced crystalloid (plasmalyte) and Group N (n = 25) received NS intraoperatively and postoperatively till 24 h after surgery.

RESULTS

The pH was lower in Group N (P < 0.05) at different time points after surgery. Similarly, more patients in Group N had pH <7.3 (P < 0.05); while the rest of the metabolic parameters were comparable in the two groups. Blood urea and serum creatinine were higher in Group N. Coagulation profile was comparable in the two groups.

CONCLUSION

Acid-base, electrolyte balance, and renal profile were better in patients receiving plasmalyte as compared to NS. Hence, it can be a wiser choice for fluid management in patients of TBI undergoing craniotomy.

High dietary salt intake increases urinary NGAL excretion and creatinine clearance in healthy young adults

In rodents and older patients with elevated blood pressure (BP), high dietary sodium increases excretion of biomarkers of kidney injury, but it is unclear whether this effect occurs in healthy young adults. The purpose of this study was to determine whether short-term high dietary salt increases urinary excretion of the kidney injury biomarkers neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in healthy young adults. Twenty participants participated in a double-blind, placebo-controlled, randomized crossover study. For 10 days each, participants were asked to consume salt (3,900 mg sodium) or placebo capsules. We measured BP during each visit, obtained 24-h urine samples for measurements of electrolytes, NGAL, and KIM-1, and assessed creatinine clearance. Compared with placebo, salt loading increased daily urinary sodium excretion (placebo: 130.3 ± 62.4 mmol/24 h vs. salt: 287.2 ± 72.0 mmol/24 h, P < 0.01). There was no difference in mean arterial BP (placebo: 77 ± 7 mmHg vs. salt: 77 ± 6 mmHg, P = 0.83) between conditions. However, salt loading increased the urinary NGAL excretion rate (placebo: 59.8 ± 44.4 ng/min vs. salt: 80.8 ± 49.5 ng/min, P < 0.01) and increased creatinine clearance (placebo: 110.5 ± 32.9 mL/min vs. salt: 145.0 ± 24.9 mL/min, P < 0.01). Urinary KIM-1 excretion was not different between conditions. In conclusion, in healthy young adults 10 days of dietary salt loading increased creatinine clearance and increased urinary excretion of the kidney injury biomarker marker NGAL but not KIM-1.NEW & NOTEWORTHY In healthy young adults, 10 days of dietary salt loading increased creatinine clearance and increased urinary excretion of the kidney injury biomarker marker neutrophil gelatinase-associated lipocalin despite no change in resting blood pressure.

[Intravenous fluid therapy and acute kidney injury - What's new?]

Optimization of intravascular volume is crucial for patients who are at risk or undergo Acute Kidney Injury. In sepsis or after acute fluid loss extensive fluid expansion is mostly needed. However, in cardiorenal syndroms fluid overload can even lead to AKI itself and reduction of intravascular volume is needed. Thus, an individualized fluid guidance in terms of a "fluid management stewartship" for the right patient, the right drug, the right route and the right dose 1 has to be applied.

Effect of 0.9% NaCl compared to plasma-lyte on biomarkers of kidney injury, sodium excretion and tubular transport proteins in patients undergoing primary uncemented hip replacement - a randomized trial

Background

Isotonic saline (IS) is widely used to secure perioperative cardiovascular stability. However, the high amount of chloride in IS can induce hyperchloremic acidosis. Therefore, IS is suspected to increase the risk of acute kidney injury (AKI). Biomarkers may have potential as indicators.

Methods

In a double-blinded, placebo-controlled study, 38 patients undergoing primary uncemented hip replacement were randomized to IS or PlasmaLyte (PL). Infusion was given during surgery as 15 ml/kg the first hour and 5 ml/kg the following two hours. Urinary samples were collected upon admission and the day after surgery. As surgery was initiated, urine was collected over the course of 4 h. Hereafter, another urine collection proceeded until the morning. Urine was analyzed for markers of AKI neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1). Arterious and venous blood samples for measurements of pH and plasma electrolytes including chloride (p-Cl) were collected as surgery was initiated, at the end of surgery and the following morning.

Results

IS induced an increase in p-Cl (111 ± 2 mmol/L after IS and 108 ± 3 after PL, p = 0.004) and a decrease in pH (7.39 ± 0.02 after IS and 7.43 ± 0.03 after PL, p = 0.001). Urinary NGAL excretion increased in both groups (ΔNGAL: 5.5 [4.1; 11.7] μg/mmol creatinine p = 0.004 after IS vs. 5.5 [2.1;9.4] μg/mmol creatinine after PL, p < 0.001). No difference was found between the groups (p = 0.839). Similarly, urinary KIM-1 excretion increased in both groups (ΔKIM-1: IS 115.8 [74.1; 156.2] ng/mmol creatinine, p < 0.001 vs. PL 152.4 [120.1; 307.9] ng/mmol creatinine, p < 0.001). No difference between the groups (p = 0.064).

FE_Na increased (1.08 ± 0.52% after IS and 1.66 ± 1.15% after PL, p = 0.032). ENaC excretion was different within groups (p = 0.019).

Conclusion

A significantly higher plasma chloride and a lower pH was present in the group receiving isotonic saline. However, u-NGAL and u-KIM-1 increased significantly in both groups after surgery despite absence of changes in creatinine. These results indicate that surgery induced subclinical kidney injury. Also, the IS group had a delayed sodium excretion as compared to the PL group which may indicate that IS affects renal sodium excretion differently from PL.

Trial registration

ClinicalTrials.gov Identifier: NCT02528448, 19/08/2015