Prevention and treatment of sepsis-induced acute kidney injury: an update

Impact of early heparin therapy on mortality in critically ill patients with sepsis associated acute kidney injury: a retrospective study from the MIMIC-IV database

Background: Inflammatory-coagulation dysfunction plays an increasingly important role in sepsis associated acute kidney injury (SAKI). This study aimed to investigate whether early heparin therapy improves survival in patients with SAKI. Methods: Patients with SAKI were identified from the Medical Information Mart for Intensive Care-IV database. The patients were divided into two groups: those who received heparin subcutaneously within 48 h after intensive care unit (ICU) admission and the control group, who received no heparin. The primary endpoint was ICU mortality, the secondary outcomes were 7-day, 14-day, 28-day, and hospital mortality. Propensity score matching (PSM), marginal structural Cox model (MSCM), and E-value analyses were performed. Results: The study included 5623 individuals with SAKI, 2410 of whom received heparin and 3213 of whom did not. There were significant effects on ICU and 28-day mortality in the overall population with PSM. MSCM further reinforces the efficacy of heparin administration reduces ICU mortality in the general population. Stratification analysis with MSCM showed that heparin administration was associated with decreased ICU mortality at various AKI stages. Heparin use was also associated with reduced 28-day mortality in patients with only female, age >60 years, and AKI stage 3, with HRs of 0.79, 0.77, and 0.60, respectively (p < 0.05). E-value analysis suggests robustness to unmeasured confounding. Conclusion: Early heparin therapy for patients with SAKI decreased ICU mortality. Further analysis demonstrated that heparin therapy was associated with reduced 28-day mortality rate in patients only among female, age > 60 years and AKI stage 3.

Preceding risks and mortality outcomes of different neonatal acute kidney injury in preterm infants

BACKGROUND

The aim of the study was to examine preceding risks and mortality outcomes of oliguric and non-oliguric acute kidney injury (AKI) in very preterm infants.

METHODS

Infants born ≤30 weeks' gestation were included. AKI was diagnosed based on neonatal Kidney Disease: Improving Global Outcomes criteria and was classified as oliguric and non-oliguric according to the urine-output criteria. We used modified Poisson and Cox proportional-hazards models for statistical comparisons.

RESULTS

Of 865 enrolled infants (gestational age 27.2 ± 2.2 weeks and birth weight 983 ± 288 gm), 204 (23.6%) developed AKI. Before AKI, the oliguric AKI group had significantly higher prevalence of small-for-gestational age (p = 0.008), lower 5-min Apgar score (p = 0.009) and acidosis (p = 0.009) on admission, and hypotension (p = 0.008) and sepsis (p = 0.001) during admission than the non-oliguric AKI group. Oliguric (adjusted risk ratio 3.58, 95% CI 2.33-5.51; adjusted hazard ratio 4.93, 95% CI 3.14-7.72) instead of non-oliguric AKI had significantly higher mortality risks than no AKI. Oliguric AKI showed significantly higher mortality risks than non-oliguric AKI, irrespective of serum creatinine and severity of AKI.

CONCLUSIONS

Categorizing AKI as oliguric and non-oliguric was crucial because of the distinct preceding risks and mortality outcomes of these two types of AKI in very preterm neonates.

IMPACT

The differences of the underlying risks and prognosis between oliguric and non-oliguric AKI in very preterm infants remain unclear. We found that oliguric AKI, but not non-oliguric AKI, carries higher mortality risks than infants without AKI. Oliguric AKI possessed higher mortality risks than non-oliguric AKI, irrespective of concomitant serum creatinine elevation and severe AKI. Oliguric AKI is more associated with prenatal small-for-the-gestational age and perinatal and postnatal adverse events, while non-oliguric AKI is associated with nephrotoxins exposures. Our finding highlighted the importance of oliguric AKI and is helpful in developing future protocol in neonatal critical care.

PDHA1 hyperacetylation-mediated lactate overproduction promotes sepsis-induced acute kidney injury via Fis1 lactylation

The increase of lactate is an independent risk factor for patients with sepsis-induced acute kidney injury (SAKI). However, whether elevated lactate directly promotes SAKI and its mechanism remain unclear. Here we revealed that downregulation of the deacetylase Sirtuin 3 (SIRT3) mediated the hyperacetylation and inactivation of pyruvate dehydrogenase E1 component subunit alpha (PDHA1), resulting in lactate overproduction in renal tubular epithelial cells. We then found that the incidence of SAKI and renal replacement therapy (RRT) in septic patients with blood lactate ≥ 4 mmol/L was increased significantly, compared with those in septic patients with blood lactate < 2 mmol/L. Further in vitro and in vivo experiments showed that additional lactate administration could directly promote SAKI. Mechanistically, lactate mediated the lactylation of mitochondrial fission 1 protein (Fis1) lysine 20 (Fis1 K20la). The increase in Fis1 K20la promoted excessive mitochondrial fission and subsequently induced ATP depletion, mitochondrial reactive oxygen species (mtROS) overproduction, and mitochondrial apoptosis. In contrast, PDHA1 activation with sodium dichloroacetate (DCA) or SIRT3 overexpression decreased lactate levels and Fis1 K20la, thereby alleviating SAKI. In conclusion, our results show that PDHA1 hyperacetylation and inactivation enhance lactate overproduction, which mediates Fis1 lactylation and exacerbates SAKI. Reducing lactate levels and Fis1 lactylation attenuate SAKI.

Early Enteral Nutrition and Sepsis-Associated Acute Kidney Injury: A Propensity Score Matched Cohort Study Based on the MIMIC-III Database

PURPOSE

We aimed to analyze the optimal timing of enteral nutrition (EN) in the treatment of sepsis and its effect on sepsis-associated acute kidney injury (SA-AKI.).

MATERIALS AND METHODS

The MIMIC-III database was employed to identify patients with sepsis who had received EN. With AKI as the primary outcome variable, receiver operating characteristic (ROC) curves were utilized to calculate the optimal cut-off time of early EN (EEN). Propensity score matching (PSM) was employed to control confounding effects. Logistic regressions and propensity score-based inverse probability of treatment weighting were utilized to assess the robustness of our findings. Comparisons within the EEN group were performed.

RESULTS

2364 patients were included in our study. With 53 hours after intensive care units (ICU) admission as the cut-off time of EEN according to the ROC curve, 1212 patients were assigned to the EEN group and the other 1152 to the delayed EN group. The risk of SA-AKI was reduced in the EEN group (odds ratio 0.319, 95% confidence interval 0.245-0.413, p<0.001). The EEN patients received fewer volumes (mL) of intravenous fluid (IVF) during their ICU stay (3750 mL vs. 5513.23 mL, p<0.001). The mediating effect of IVF was significant (p<0.001 for the average causal mediation effect). No significant differences were found within the EEN group (0-48 hours vs. 48-53 hours), except that patients initiating EN within 48 hours spent fewer days in ICU and hospital.

CONCLUSION

EEN is associated with decreased risk of SA-AKI, and this beneficial effect may be proportionally mediated by IVF volume.

Feasibility study using longitudinal bioelectrical impedance analysis to evaluate body water status during fluid resuscitation in a swine sepsis model

Fluid resuscitation is crucial in the initial management of sepsis; however, little is known about the serial changes and overall distribution of fluids administered into the body. To identify the feasibility of longitudinal bioelectrical impedance analysis during fluid treatment, a preclinical porcine model of Escherichia coli-induced sepsis was used. After sepsis induction, pigs were treated with fluid and vasopressors and monitored for up to 12 h after bacterial infusion or until death. Bipolar electrodes for bioelectrical impedance analysis were attached to the left extremities and measurements were performed every 10 min. Among the 12 subjects, 7 pigs expired during the experiment, and the median survival was 9.5 h. As sepsis progressed with an increase in cumulative fluid balance, R₀ [∝ 1/extracellular water (ECW)] decreased, while R_i [∝ 1/intracellular water (ICW)] and ratio of extracellular water to total body water (ECW/TBW) increased. The phase angle constantly decreased throughout the monitoring period, and all non-survivors died when the phase angle decreased by more than 10%. Among the variables, ΔR₀ and Δphase angle showed moderate negative correlations, and ΔECW/TBW showed a moderate positive correlation with the hourly fluid balance. Compared to survivors, a greater increase in ΔECW/TBW and a decrease in phase angle were observed in non-survivors over time, with an increase in cumulative fluid balance. Differences in ΔECW/TBW and phase angle emerged at 240 min when the difference in cumulative fluid balance between the two groups (survivors vs non-survivors) exceeded 1000 mL. In conclusion, continuous measurements of bioelectrical impedance analysis in a porcine sepsis model are feasible and may reflect changes in the body water profile during fluid resuscitation.

Sepsis and Acute Kidney Injury: A Review Focusing on the Bidirectional Interplay

Although sepsis and acute kidney injury (AKI) have a bidirectional interplay, the pathophysiological mechanisms between AKI and sepsis are not clarified and worthy of a comprehensive and updated review. The primary pathophysiology of sepsis-associated AKI (SA-AKI) includes inflammatory cascade, macrovascular and microvascular dysfunction, cell cycle arrest, and apoptosis. The pathophysiology of sepsis following AKI contains fluid overload, hyperinflammatory state, immunosuppression, and infection associated with kidney replacement therapy and catheter cannulation. The preventive strategies for SA-AKI are non-specific, mainly focusing on infection control and preventing further kidney insults. On the other hand, the preventive strategies for sepsis following AKI might focus on decreasing some metabolites, cytokines, or molecules harmful to our immunity, supplementing vitamin D3 for its immunomodulation effect, and avoiding fluid overload and unnecessary catheter cannulation. To date, several limitations persistently prohibit the understanding of the bidirectional pathophysiologies. Conducting studies, such as the Kidney Precision Medicine Project, to investigate human kidney tissue and establishing parameters or scores better to determine the occurrence timing of sepsis and AKI and the definition of SA-AKI might be the prospects to unveil the mystery and improve the prognoses of AKI patients.

Blockade of mIL‐6R alleviated lipopolysaccharide‐induced systemic inflammatory response syndrome by suppressing NF‐κB‐mediated Ccl2 expression and inflammasome activation

Systemic inflammatory response syndrome (SIRS) is characterized by dysregulated cytokine release, immune responses and is associated with organ dysfunction. IL‐6R blockade indicates promising therapeutic effects in cytokine release storm but still remains unknown in SIRS. To address the issue, we generated the human il‐6r knock‐in mice and a defined epitope murine anti‐human membrane‐bound IL‐6R (mIL‐6R) mAb named h‐mIL‐6R mAb. We found that the h‐mIL‐6R and the commercial IL‐6R mAb Tocilizumab significantly improved the survival rate, reduced the levels of TNF‐α, IL‐6, IL‐1β, IFN‐γ, transaminases and blood urea nitrogen of LPS‐induced SIRS mice. Besides, the h‐mIL‐6R mAb could also dramatically reduce the levels of inflammatory cytokines in LPS‐treated THP‐1 cells in vitro. RNA‐seq analysis indicated that the h‐mIL‐6R mAb could regulate LPS‐induced activation of NF‐κB/Ccl2 and NOD‐like receptor signaling pathways. Furthermore, we found that the h‐mIL‐6R mAb could forwardly inhibit Ccl2 expression and NLRP3‐mediated pyroptosis by suppressing NF‐κB in combination with the NF‐κB inhibitor. Collectively, mIL‐6R mAbs suppressed NF‐κB/Ccl2 signaling and inflammasome activation. IL‐6R mAbs are potential alternative therapeutics for suppressing excessive cytokine release, over‐activated inflammatory responses and alleviating organ injuries in SIRS.

Central venous pressure and acute kidney injury in critically ill patients with multiple comorbidities: a large retrospective cohort study

Background

Given the traditional acceptance of higher central venous pressure (CVP) levels, clinicians ignore the incidence of acute kidney injury (AKI). The objective of this study was to assess whether elevated CVP is associated with increased AKI in critically ill patients with multiple comorbidities.

Methods

This was a retrospective observational cohort study using data collected from the Medical Information Mart for Intensive Care (MIMIC)-III open-source clinical database (version 1.4). Critically ill adult patients with CVP and serum creatinine measurement records were included. Linear and multivariable logistic regression were performed to determine the association between elevated CVP and AKI.

Results

A total of 11,135 patients were enrolled in our study. Critically ill patients in higher quartiles of mean CVP presented greater KDIGO AKI severity stages at 2 and 7 days. Linear regression showed that the CVP quartile was positively correlated with the incidence of AKI within 2 (R² = 0.991, P = 0.004) and 7 days (R² = 0.990, P = 0.005). Furthermore, patients in the highest quartile of mean CVP exhibited an increased risk of AKI at 7 days than those in the lowest quartile of mean CVP with an odds ratio of 2.80 (95% confidence interval: 2.32–3.37) after adjusting for demographics, treatments and comorbidities. The adjusted odds of AKI were 1.10 (95% confidence interval: 1.08–1.12) per 1 mmHg increase in mean CVP.

Conclusions

Elevated CVP is associated with an increased risk of AKI in critically ill patients with multiple comorbidities. The optimal CVP should be personalized and maintained at a low level to avoid AKI in critical care settings.

Cathelicidin protects mice from Rhabdomyolysis-induced Acute Kidney Injury

Background: Cathelicidins are ancient and well-conserved antimicrobial peptides (AMPs) with intriguing immunomodulatory properties in both infectious and non-infectious inflammatory diseases. In addition to direct antimicrobial activity, cathelicidins also participate in several signaling pathways inducing both pro-inflammatory and anti-inflammatory effects. Acute kidney injury (AKI) is common in critically ill patients and is associated with high mortality and morbidity. Rhabdomyolysis is a major trigger of AKI. Objectives: Here, we investigated the role of cathelicidins in non-infectious Acute kidney Injury (AKI). Method: Using an experimental model of rhabdomyolysis, we induced AKI in wild-type and cathelicidin-related AMP knockout (CRAMP^-/-) mice. Results: We previously demonstrated that CRAMP^-/- mice, as opposed wild-type mice, are protected from AKI during sepsis induced by cecal ligation and puncture. Conversely, in the current study, we show that CRAMP^-/- mice are more susceptible to the rhabdomyolysis model of AKI. A more in-depth investigation of wild-type and CRAMP^-/- mice revealed important differences in the levels of several inflammatory mediators. Conclusion: Cathelicidins can induce a varied and even opposing repertoire of immune-inflammatory responses depending on the subjacent disease and the cellular context.

SHP2 inhibitor PHPS1 ameliorates acute kidney injury by Erk1/2-STAT3 signaling in a combined murine hemorrhage followed by septic challenge model

BACKGROUND

Hypovolemic shock and septic challenge are two major causes of acute kidney injury (AKI) in the clinic setting. Src homology 2 domain-containing phosphatase 2 (SHP2) is one of the major protein phosphatase tyrosine phosphatase (PTPs), which play a significant role in maintaining immunological homeostasis by regulating many facets of immune cell signaling. In this study, we explored whether SHP2 signaling contributed to development of AKI sequential hemorrhage (Hem) and cecal ligation and puncture (CLP) and whether inactivation of SHP2 through administration of its selective inhibitor, phenylhydrazonopyrazolone sulfonate 1 (PHPS1), attenuated this injury.

METHODS

Male C57BL/6 mice were subjected to Hem (a "priming" insult) followed by CLP or sham-Hem plus sham-CLP (S/S) as controls. Samples of blood and kidney were harvested at 24 h post CLP. The expression of neutrophil gelatinase-associated lipocalin (NGAL), high mobility group box 1 (HMGB1), caspase3 as well as SHP2:phospho-SHP2, extracellular-regulated kinase (Erk1/2): phospho-Erk1/2, and signal transducer and activator of transcription 3 (STAT3):phospho-STAT3 protein in kidney tissues were detected by Western blotting. The levels of creatinine (Cre) and blood urea nitrogen (BUN) in serum were measured according to the manufacturer's instructions. Blood inflammatory cytokine/chemokine levels were detected by ELISA.

RESULTS

We found that indices of kidney injury, including levels of BUN, Cre and NGAL as well as histopathologic changes, were significantly increased after Hem/CLP in comparison with that in the S/S group. Furthermore, Hem/CLP resulted in elevated serum levels of inflammatory cytokines/chemokines, and induced increased levels of HMGB1, SHP2:phospho-SHP2, Erk1/2:phospho-Erk1/2, and STAT3:phospho-STAT3 protein expression in the kidney. Treatment with PHPS1 markedly attenuated these Hem/CLP-induced changes.

CONCLUSIONS

In conclusion, our data indicate that SHP2 inhibition attenuates AKI induced by our double-hit/sequential insult model of Hem/CLP and that this protective action may be attributable to its ability to mitigate activation of the Erk1/2 and STAT3 signaling pathway. We believe this is a potentially important finding with clinical implications warranting further investigation.

Raw and salt-processed Achyranthes bidentata attenuate LPS-induced acute kidney injury by inhibiting ROS and apoptosis via an estrogen-like pathway

BACKGROUND

Traditional Chinese medicine suggests that Radix Achyranthis Bidentatae nourishes and protects the kidneys, the effect of which is enhanced following a salt treatment. Raw and salt-processed Achyranthes bidentata are produced via different processing techniques from the same crude Achyranthes root. The anti-inflammatory and immunomodulatory properties of this plant have been verified earlier. However, there is a scarcity of experimental evidence for the renal-protective effects.

AIM

The purpose of present study is to compare the protective effects of raw and salt-processed Achyranthes on lipopolysaccharide (LPS) - induced acute kidney injury in mice and chemically characterize their extracts.

METHOD

The monomer components of raw and salt-processed Achyranthes extracts were analyzed using high performance liquid chromatography (HPLC). The aggregation and distribution of 2-Deoxy-D-glucose (2-DG) near infrared fluorescence probe in mice was examined with a small animal imaging systems. The pathological and morphological changes of kidneys were observed by H&E staining, and the serum urea nitrogen (BUN) and serum creatinine (Scr) levels were used to evaluate the renal function. The levels of cytokines in serum were detected by cytometric bead array. Flow cytometry assay was performed to assess the apoptosis and reactive oxygen species (ROS) in the kidney cells, and cell surface marker expression including CD45⁺, F4/80⁺, and Ly-6G⁺. The estrogenic activities of the raw and salt-processed Achyranthes were observed by uterine weight gain test in sexually immature mice. Western blot was used to detect the protein expression levels in the kidney.

RESULTS

Chemical analysis showed that the salt-processed Achyranthes contained more ginsenoside Ro and chikusetsusaponin Ⅳa than the raw Achyranthes, but there was no difference in the contents of β-ecdysterone, 25R-inokosterone, and 25S-inokosterone.in vivo near-infrared fluorescence imaging showed a significant reduced inflammation in the AKI mice. Histological studies showed that the raw and salt-processed Achyranthes markedly decreased the inflammatory infiltration, swelling and vacuolar degeneration in renal tissues and the Scr and BUN. Importantly, the raw and salt-processed Achyranthes extracts demonstrated different degrees of inhibition on the LPS-induced AKI, with salt-processed Achyranthes showing better inhibition. Results of flow cytometry showed a significant inhibition of IFN-γ, TNF-α, and IL-2, and promoted IL-10, along with reduced macrophages (CD45 + F4/80+), neutrophils (CD45+ Ly-6G+) and phagocytes. Furthermore, the extracts reduced the accumulation of ROS and apoptosis in the kidney, and also regulated the expression of apoptosis marker proteins TLR4, Bcl-2, Bax, cleaved caspase 3 and cleaved caspase 9 levels. Notably, they increased ERα, ERβ, and GPR30 in the renal tissues of AKI mice and LPS non-treated mice. In the subsequent experiments, it was found that the raw and salt-processed Achyranthes extracts increased the uterine coefficient in sexually immature mice, improved the LPS-induced decrease in NRK52e cell viability, and reduced the apoptosis, which could be antagonized by ICI182, 780 (estrogen receptor-unspecific antagonist, Faslodex).

CONCLUSIONS

The renal-protective effect of raw and salt-processed Achyranthes was exhibited through antiapoptotic and antioxidant mechanisms via an estrogen-like pathway, along with a modulation of the inflammatory response by regulating immune cells. Ginsenoside Ro and Chikusetsu saponin IVa were found to be the key factors to enhance the protective effect of salt-processed Achyranthes.

Pharmacokinetics and Pharmacodynamics of Anti-infective Agents during Continuous Veno-venous Hemofiltration in Critically Ill Patients: Lessons Learned from an Ancillary Study of the IVOIRE Trial

Background

Hemofiltration rate, changes in blood and ultrafiltration flow, and discrepancies between the prescribed and administered doses strongly influence pharmacokinetics (PK) and pharmacodynamics (PD) of antimicrobial agents during continuous veno-venous hemofiltration (CVVH) in critically ill patients.

Methods

Ancillary data were from the prospective multicenter IVOIRE (hIgh VOlume in Intensive caRE) study. High volume (HV, 70 mL/kg/h) was at random compared with standard volume (SV, 35 mL/kg/h) CVVH in septic shock patients with acute kidney injury (AKI). PK/PD parameters for all antimicrobial agents used in each patient were studied during five days.

Results

Antimicrobial treatment met efficacy targets for both percentage of time above the minimal inhibitory concentration and inhibitory quotient. A significant correlation was observed between the ultrafiltration flow and total systemic clearance (Spearman test: P < 0.005) and between CVVH clearance and drug elimination half-life (Spearman test: P < 0.005). All agents were easily filtered. Mean sieving coefficient ranged from 38.7% to 96.7%. Mean elimination half-life of all agents was significantly shorter during HV-CVVH (from 1.29 to 28.54 h) than during SV-CVVH (from 1.51 to 33.85 h) (P < 0.05).

Conclusions

This study confirms that CVVH influences the PK/PD behavior of most antimicrobial agents. Antimicrobial elimination was directly correlated with convection rate. Current antimicrobial dose recommendations will expose patients to underdosing and increase the risk for treatment failure and development of resistance. Dose recommendations are proposed for some major antibiotic and antifungal treatments in patients receiving at least 25 mL/kg/h CVVH.

Fish oils protects against cecal ligation and puncture‑induced septic acute kidney injury via the regulation of inflammation, oxidative stress and apoptosis

Septic acute kidney injury (AKI) is usually caused by sepsis. ω3 fatty acid has been reported to suppress sepsis-induced organ dysfunction to a certain degree. The present study aimed to investigate the effects of ω3 fatty acid in septic renal injury. Sprague Dawley rats were used to establish a cecal ligation and puncture (CLP) model in order to mimic the development of septic injury. The rats were treated with dexamethasone and fish oils (FOs) for 4 days prior to CLP. Alterations in the morphology of the tissues, the renal function and the induction of inflammation, oxidative stress and apoptosis were evaluated. The effects of FOs on nuclear factor-κB (NF-κB), JAK2/STAT3 and p38-MAPK were determined. The rats of the CLP model group exhibited low survival rates and increased expression of serum creatine, blood urea nitrogen, neutrophil gelatinase-associated lipocalin, kidney injury molecule-1 and of proinflammatory cytokines. In addition, the levels of the markers of oxidative injury and apoptosis were increased. The induction of renal injury was notably reversed by administration of dexamethasone and FOs. The expression levels of the protein markers involved in inflammation and apoptosis were measured and the results indicated that FOs inhibited JAK/STAT3 and p-38MAPK signaling, while they concomitantly increased the expression of NF-κB. The present study highlighted that FOs improve CLP-induced mortality and renal injury by inhibiting inflammation, oxidative stress and apoptosis.

Mechanisms and treatment of organ failure in sepsis

Sepsis is a dysregulated immune response to an infection that leads to organ dysfunction. Knowledge of the pathophysiology of organ failure in sepsis is crucial for optimizing the management and treatment of patients and for the development of potential new therapies. In clinical practice, six major organ systems - the cardiovascular (including the microcirculation), respiratory, renal, neurological, haematological and hepatic systems - can be assessed and monitored, whereas others, such as the gut, are less accessible. Over the past 2 decades, considerable amounts of new data have helped improve our understanding of sepsis pathophysiology, including the regulation of inflammatory pathways and the role played by immune suppression during sepsis. The effects of impaired cellular function, including mitochondrial dysfunction and altered cell death mechanisms, on the development of organ dysfunction are also being unravelled. Insights have been gained into interactions between key organs (such as the kidneys and the gut) and organ-organ crosstalk during sepsis. The important role of the microcirculation in sepsis is increasingly apparent, and new techniques have been developed that make it possible to visualize the microcirculation at the bedside, although these techniques are only research tools at present.

A simple risk score for prediction of sepsis associated-acute kidney injury in critically ill patients

BACKGROUND

Sepsis is common and frequently fatal condition in critically ill patients and is a major cause of acute kidney injury (AKI). In this retrospective study, we sought to develop a comprehensive risk score model of sepsis associated-AKI (SA-AKI).

METHODS

A total of 2617 patients were randomly assigned to a development (1554 patients) and a validation group (777 patients). The risk score model for SA-AKI was developed with multivariate regression analysis in development group and the model was further evaluated on validation group.

RESULTS

We identified 16 independent predictors of SA-AKI in development group (age ≥ 60 years, hypertension/coronary heart disease, diabetes, chronic kidney disease, heart failure, chronic obstructive pulmonary disease, acute severe pancreatitis, hypotension, hypoproteinemia, lactic acidosis, the length of stay in intensive care unit(ICU), 60 g/L<hemoglobin < 90 g/L, hemoglobin ≤ 60 g/L, and ≥ 2 failed organs. This model had excellent performance characteristics in validation cohort(c statistic 0.857, 95% CI 0.839-0.874).

CONCLUSION

The novel risk score model for SA-AKI in ICU can identify patients at high risk to develop AKI. Application of this model could help clinicians to stratify patients for primary prevention, surveillance and early therapeutic intervention to improve care and prognosis of sepsis patients in ICU.

Retrospective analysis of the association between intraoperative magnesium sulfate infusion and postoperative acute kidney injury after major laparoscopic abdominal surgery

Magnesium sulfate can be used as a co-adjuvant drug during the perioperative period and has multiple benefits. Recent evidence suggested that perioperative magnesium sulfate infusion may lower the risk of postoperative acute kidney injury (AKI). We investigated the association between intraoperative magnesium sulfate infusion and incidence of AKI after major laparoscopic abdominal surgery. We retrospectively analyzed the medical records of adult patients 20 years or older who underwent elective major laparoscopic abdominal surgery (>2 hours) between 2010 and 2016. We investigated the association between intraoperative magnesium sulfate infusion and the incidence of postoperative AKI until postoperative day (POD) 3 using a multivariable logistic regression analysis. We included 3,828 patients in this analysis; 357 patients (9.3%) received an intraoperative magnesium sulfate infusion and 186 patients (4.9%) developed postoperative AKI by POD 3. A multivariable logistic regression analysis showed that magnesium infusion was associated with a significant decrease (63%) in postoperative AKI (odds ratio, 0.37; 95% confidence interval, 0.14–0.94; P = 0.037). Our study suggested that intraoperative magnesium sulfate infusion is associated with a reduced risk of postoperative AKI until POD 3 for patients who underwent laparoscopic major abdominal surgery. Well-designed, prospective studies should be conducted to further substantiate these findings.

Acute kidney injury in postoperative shock: is hyperoncotic albumin administration an unrecognized resuscitation risk factor?

BACKGROUND

The use of hyperoncotic albumin (HA) for shock resuscitation is controversial given concerns about its cost, effectiveness, and potential for nephrotoxicity. We evaluated the association between early exposure to hyperoncotic albumin (within the first 48 h of onset of shock) and acute organ dysfunction in post-surgical patients with shock.

METHODS

This retrospective, cohort study included 11,512 perioperative patients with shock from 2009 to 2012. Shock was defined as requirement for vasopressors to maintain adequate mean arterial pressure and/or elevated lactate (> 2.2 mmol/L). Subsets of 3600 were selected after propensity score and exact matching on demographics, comorbidities, and treatment variables (> 30). There was a preponderance of cardiac surgery patients. Proportional odds logistic regression, multivariable logistic regression or Cox proportional hazard regression models measured association between hyperoncotic albumin and acute kidney injury (AKI), hepatic injury, ICU days, and mortality.

RESULTS

Hyperoncotic albumin-exposed patients showed greater risk of acute kidney injury compared to controls (OR 1.10, 95% CI 1.04, 1.17. P = 0.002), after adjusting for imbalanced co-variables. Within matched patients, 20.3%, 2.9%, and 4.4% of HA patients experienced KDIGO stages 1-3 AKI, versus 19.6%, 2.5%, and 3.0% of controls. There was no difference in hepatic injury (OR 1.16; 98.3% CI 0.85, 1.58); ICU days, (HR 1.05; 98.3% CI 1.00, 1.11); or mortality, (OR 0.88; 98.3% CI 0.64, 1.20).

CONCLUSIONS

Early exposure to hyperoncotic albumin in postoperative shock appeared to be associated with acute kidney injury. There did not appear to be any association with hepatic injury, mortality, or ICU days. The clinical and economic implications of this finding warrant further investigation.

Renal failure in critically ill patients, beware of applying (central venous) pressure on the kidney

The central venous pressure (CVP) is traditionally used as a surrogate of intravascular volume. CVP measurements therefore are often applied at the bedside to guide fluid administration in postoperative and critically ill patients. Pursuing high CVP levels has recently been challenged. A high CVP might impede venous return to the heart and disturb microcirculatory blood flow which may cause tissue congestion and organ failure. By imposing an increased "afterload" on the kidney, an elevated CVP will particularly harm kidney hemodynamics and promote acute kidney injury (AKI) even in the absence of volume overload. Maintaining the lowest possible CVP should become routine to prevent and treat AKI, especially when associated with septic shock, cardiac surgery, mechanical ventilation, and intra-abdominal hypertension.

Prolonged intermittent renal replacement therapy in children

Wide ranges of age and weight in pediatric patients makes renal replacement therapy (RRT) in acute kidney injury (AKI) challenging, particularly in the pediatric intensive care unit (PICU), wherein children are often hemodynamically unstable. Standard hemodialysis (HD) is difficult in this group of children and continuous veno-venous hemofiltration/dialysis (CVVH/D) has been the accepted modality in the developed world. Unfortunately, due to cost constraints, CVVH/D is often not available and peritoneal dialysis (PD) remains the common mode of RRT in resource-poor facilities. Acute PD has its drawbacks, and intermittent HD (IHD) done slowly over a prolonged period has been explored as an alternative. Various modes of slow sustained IHD have been described in the literature with the recently introduced term prolonged intermittent RRT (PIRRT) serving as an umbrella terminology for all of these modes. PIRRT has been widely accepted in adults with studies showing it to be as effective as CVVH/D but with an added advantage of being more cost-effective. Pediatric data, though scanty, has been promising. In this current review, we elaborate on the practical aspects of undertaking PIRRT in children as well as summarize its current status.

Understanding fluid homoeostasis in infants and children: part 2

Part two of this article focuses on the care and management of infants and children who are seriously ill and who have lost so much fluid that they have entered a state of shock. The pathophysiology of shock is reviewed and the types and stages of shock are considered. The challenges of identifying shock are explored and the management of fluid resuscitation with colloids rather than crystalloids is analysed. An overview of the complex management of a young person in shock is provided using a case history format. The article offers the opportunity to extend readers' knowledge of some of the special tests that may be required to support the diagnosis of shock and provides an overview of the expected results.

Dexmedetomidine restores septic renal function via promoting inflammation resolution in a rat sepsis model

BACKGROUND

Acute kidney injury occurred after sepsis, resulting in high mortality. This research aims to elucidate the mechanistic effect of DEX on the renal inflammation resolution during sepsis in rats.

METHODS

The rats were randomly divided into a sham group and the other three cecal ligation and puncture (CLP) model groups, based on different treatments: placebo, DEX and 2-adrenergic receptor (AR) inhibitor atipamezole (AT) treatment (DEX + AT) groups. The survival of septic rats within 24 h was recorded. Tissue pathology, plasma IL-1β, IL-6, TNF-α, lipoxygenase-5 and lipoxin A4 were evaluated. Western blotting and immunostaining was used to determine expression of TLR4, IκB, IKK, NF-κB p65 and pp65 in kidney tissue. Then qPCR was used to analyze the mRNA expression of renal α_2A-AR, α_2B-AR and α_2C-AR.

RESULTS

Rat mortality and kidney inflammation were significantly increased in septic rats. Specifically, IL-1β, IL-6 and TNF-α plasma levels, NF-κB activity, and TLR4 expression in rat kidney tissues were increased after CLP. In the DEX treatment group, mortality was reduced, histology changes were minor, and lipoxygenase-5, and lipoxin A4 expression were increased. The expression of IL-1β, IL-6 and TNF-α, NF-κB activity and TLR4 expression in rat kidney tissues were also decreased. These results indicated that DEX treatment alleviates acute kidney injury induced by CLP. However, the effects of DEX were apparently suppressed by atipamezole in the DEX + AT group.

CONCLUSION

The current study demonstrated the protective effect of DEX on CLP-induced kidney injury, which may be effective by attenuating NF-κB pathway activation with lipoxin A4.

Proenkephalin, Neutrophil Gelatinase-Associated Lipocalin, and Estimated Glomerular Filtration Rates in Patients With Sepsis

Background

Proenkephalin (PENK) has been suggested as a novel biomarker for kidney function. We investigated the diagnostic and prognostic utility of plasma PENK in comparison with neutrophil gelatinase-associated lipocalin (NGAL) and estimated glomerular filtration rates (eGFR) in septic patients.

Methods

A total of 167 septic patients were enrolled: 99 with sepsis, 37 with septic shock, and 31 with suspected sepsis. PENK and NGAL concentrations were measured and GFR was estimated by using the isotope dilution mass spectrometry traceable-Modification of Diet in Renal Disease (MDRD) Study and three Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations: CKD-EPI_Cr, CDK-EPI_CysC, and CKD-EPI_Cr-CysC. The PENK, NGAL, and eGFR results were compared according to sepsis severity, presence or absence of acute kidney injury (AKI), and clinical outcomes.

Results

The PENK, NGAL, and eGFR results were significantly associated with sepsis severity and differed significantly between patients with and without AKI only in the sepsis group (all P<0.05). PENK was superior to NGAL in predicting AKI (P=0.022) and renal replacement therapy (RRT) (P=0.0085). Regardless of the variable GFR category by the different eGFR equations, PENK showed constant and significant associations with all eGFR equations. Unlike NGAL, PENK was not influenced by inflammation and predicted the 30-day mortality.

Conclusions

PENK is a highly sensitive and objective biomarker of AKI and RRT and is useful for prognosis prediction in septic patients. With its diagnostic robustness and predictive power for survival, PENK constitutes a promising biomarker in critical care settings including sepsis.

Sepsis and Septic Shock Strategies

Three therapeutic principles most substantially improve organ dysfunction and survival in sepsis: early, appropriate antimicrobial therapy; restoration of adequate cellular perfusion; timely source control. The new definitions of sepsis and septic shock reflect the inadequate sensitivity, specify, and lack of prognostication of systemic inflammatory response syndrome criteria. Sequential (sepsis-related) organ failure assessment more effectively prognosticates in sepsis and critical illness. Inadequate cellular perfusion accelerates injury and reestablishing perfusion limits injury. Multiple organ systems are affected by sepsis and septic shock and an evidence-based multipronged approach to systems-based therapy in critical illness results in improve outcomes.

Epidemiology of acute kidney injury and chronic kidney disease in the intensive care unit

OBJECTIVE

To describe the epidemiology of acute kidney injury, its relationship to chronic kidney disease, and the factors associated with its incidence.

METHODS

A cohort study and follow-up were conducted in an intensive care unit in Montevideo, Uruguay. We included patients admitted between November 2014 and October 2015 who were older than 15 years of age and who had at least two measurements of serum creatinine. We excluded patients who were hospitalized for less than 48 hours, patients who died at the time of hospitalization, and patients with chronic renal disease who were on hemodialysis or peritoneal dialysis. There were no interventions. Acute kidney injury was defined according to the criteria set forth in Acute Kidney Injury Disease: Improving Global Outcomes, and chronic kidney disease was defined according to the Chronic Kidney Disease Work Group.

RESULTS

We included 401 patients, 56.6% male, median age of 68 years (interquartile range (IQR) 51-79 years). The diagnosis at admission was severe sepsis 36.3%, neurocritical 16.3%, polytrauma 15.2%, and other 32.2%. The incidence of acute kidney injury was 50.1%, and 14.1% of the patients suffered from chronic kidney disease. The incidence of acute septic kidney injury was 75.3%. Mortality in patients with or without acute kidney injury was 41.8% and 14%, respectively (p < 0.001). In the multivariate analysis, the most significant variables for acute kidney injury were chronic kidney disease (odds ratio (OR) 5.39, 95%CI 2.04 - 14.29, p = 0.001), shock (OR 3.94, 95%CI 1.72 - 9.07, p = 0.001), and severe sepsis (OR 7.79, 95%CI 2.02 - 29.97, p = 0.003).

CONCLUSION

The incidence of acute kidney injury is high mainly in septic patients. Chronic kidney disease was independently associated with the development of acute kidney injury.

[Acute kidney injury : A clinical syndrome]

Acute kidney injury (AKI) is a clinical syndrome occurring in the context of multiple and diverse disease entities. Although the term AKI implies renal damage as well as functional impairment or a combination of both, diagnosis is solely based on the functional parameters serum creatinine and urine output. Independent of the underlying disease and even assuming full recovery of renal function, AKI is associated with increased morbidity and mortality not only during the acute situation, but also long term. Awareness of the individual risk profile of each patient and the variety of causes and clinical manifestations of AKI is pivotal for prophylaxis, diagnosis, and therapy. The complexity of the clinical syndrome in the context of sepsis, solid organ transplantation, malignancy, and autoimmune diseases requires differentiated diagnostic and therapeutic approaches and interdisciplinary care.

Factors associated with increased pancreatic enzymes in septic patients: a prospective study

Background

The perfusion of splanchnic organs is deeply altered in patients with septic shock. The aim of the study is to identify the predictive factors of septic shock-induced increase of serum lipase and amylase and to assess and evaluate its prognostic impact.

Methods

We conducted a prospective observational study. All adult patients admitted with septic shock were eligible for our study. Serum lipase and amylase were measured on admission. Patients with and those without increased pancreatic enzymes were compared. Predictive factors of pancreatic insult identified by the univariate analysis were integrated in a stepwise multivariate analysis. Odds ratios (OR) with the 95% confidence interval (CI) were calculated accordingly. Second, the sensitivity and the specificity of amylase and lipase to predict intensive care unit (ICU) mortality were identified through the Receiver Operator Curve.

Results

Fifty patients were included. Median [quartiles] age was 68.5 [58–81] years. The APACHE II score was 26 [20–31]. Twenty-three patients (46%) had increased serum amylase and/or serum lipase. Diabetes mellitus (OR = 16; 95% CI [1.7–153.5]; p = 0.016), increased blood urea nitrogen (OR = 1.12; 95% CI [1.02–1.20], p = 0.016), and decreased C-reactive protein (OR = 0.97; 95% CI [0.96–0.99]; p = 0.027) were identified as independent factors predicting increased pancreatic enzymes. Twenty patients (40%) died in the ICU. Neither serum amylase level nor serum lipase level was significantly different between survivors and non-survivors (respectively 49 [27.7–106] versus 85.1 [20.1–165] UI/L; p = 0.7 and 165 [88–316] versus 120 [65.5–592] UI/L; p = 0.952).

Conclusion

Increase of pancreatic enzymes is common in patients with septic shock. Diabetes and impaired renal function are predictive of increased pancreatic enzymes. Such finding does not carry any negative prognostic value.

The future of critical care: renal support in 2027

Since its inception four decades ago, both the clinical and technologic aspects of continuous renal replacement therapy (CRRT) have evolved substantially. Devices now specifically designed for critically ill patients with acute kidney injury are widely available and the clinical challenges associated with treating this complex patient population continue to be addressed. However, several important questions remain unanswered, leaving doubts in the minds of many clinicians about therapy prescription/delivery and patient management. Specifically, questions surrounding therapy dosing, timing of initiation and termination, fluid management, anticoagulation, drug dosing, and data analytics may lead to inconsistent delivery of CRRT and even reluctance to prescribe it. In this review, we discuss current limitations of CRRT and potential solutions over the next decade from both a patient management and a technology perspective. We also address the issue of sustainability for CRRT and related therapies beyond 2027 and raise several points for consideration.

Chemical and microbiological stability, anticoagulant efficacy and toxicity of 35 and 90 mM trisodium citrate solutions stored in plastic syringes

Background

Trisodium citrate is an interesting alternative to heparin for the prevention of circuit clotting during extracorporeal procedures, but some protocols require non-commercially available citrate concentrations. Little published information is available about the stability of diluted citrate solutions.

Objectives

To evaluate the long-term stability, efficacy and toxicity of 35 mM and 90 mM trisodium citrate solutions prepared by diluting a commercially available sterile solution, stored in plastic syringes and used as an anticoagulant during citrate bag changes in the coupled plasma filtration adsorption (CPFA) technique in the COMPACT-2 clinical trial.

Methods

The chemical stability of trisodium citrate solutions was evaluated by high-performance liquid chromatography after 7, 14, 21 and 28 days of storage. Sterility tests were performed both immediately after preparation and after 28 days of storage.

Results

After 28 days of storage, the concentration of trisodium citrate had not changed in comparison with day 1, and both solutions passed the sterility test. A preliminary test indicated that a 35 mM solution is insufficient to ensure an effective anticoagulant action on an extracorporeal circuit, but the 90 mM solution was successfully used for 7 CPFA treatments in 2 patients, without clinical signs of toxicity.

Conclusions

Both the 35 mM and 90 mM solutions are chemically and microbiologically stable for 28 days when stored at room temperature in 50 mL syringes protected by light. The 90 mM solution is an effective and safe regional anticoagulant in the CPFA protocol.

Trial registration number

NCT01639664.

Pancreatic injury in patients with septic shock: A literature review

Sepsis and septic shock are life threatening condition associated with high mortality rate in critically-ill patients. This high mortality is mainly related to the inadequacy between oxygen delivery and cellular demand leading to the onset of multiorgan dysfunction. Whether this multiorgan failure affect the pancreas is not fully investigated. In fact, pancreatic injury may occur because of ischemia, overwhelming inflammatory response, oxidative stress, cellular apoptosis and/or metabolic derangement. Increased serum amylase and/or lipase levels are common in patients with septic shock. However, imaging test rarely reveal significant pancreatic damage. Whether pancreatic dysfunction does affect the prognosis of patients with septic shock or not is still a matter of debate. In fact, only few studies with limited sample size assessed the clinical relevance of the pancreatic injury in this group of patients. In this review, we aimed to describe the epidemiology and the physiopathology of pancreatic injury in septic shock patients, to clarify whether it requires specific management and to assess its prognostic value. Our main finding is that pancreatic injury does not significantly affect the outcome in septic shock patients. Hence, increased serum pancreatic enzymes without clinical features of acute pancreatitis do not require further imaging investigations and specific therapeutic intervention.

Knockout of interleukin-17A protects against sepsis-associated acute kidney injury

Background

Sepsis-associated acute kidney injury (SA-AKI) is an independent risk factor for death in patients with sepsis, but treatment for it is limited. To improve the diagnosis and treatment of SA-AKI, we must first understand its pathogenesis. Recently, interleukin (IL)-17A has been shown to be associated with the pathogenesis of acute kidney injury and sepsis, but its role in SA-AKI remains unclear.

Methods

SA-AKI was induced in male C57BL/6 and IL-17A^−/− mice using cecal ligation and puncture (CLP) operations for 24 h.

Results

At 7 days, only seven mice survived in the wild-type septic group, but nine survived in the IL-17A^−/− septic group, corresponding to survival rates of 25 % and 45 %, respectively. At 24 h after CLP operations, both wild-type and IL-17A^−/− septic mice developed kidney injury. The IL-17A^−/− septic mice exhibited decreased serum creatinine and blood urea nitrogen levels and an improved acute tubular necrosis score. The IL-17A^−/− septic mice exhibited decreased IL-6, interferon-γ, tumor necrosis factor-α, CXCL1, CXCL2, and CXCL5 expression in kidney tissue, but increased IL-10 expression. In addition, renal neutrophil infiltration was attenuated significantly in the IL-17A^−/− septic group. Moreover, IL-17A^−/− septic mice showed significantly decreased apoptosis of tubular epithelial cells, including decreased TUNEL-positive tubular cell number and cleaved caspase-3 level, compared with the wild-type CLP group. Their Bax/Bcl-2 expression ratio was also increased.

Conclusions

Our study demonstrates that IL-17A knockout could protect against SA-AKI. We show that IL-17A plays a pathogenic role in SA-AKI by increasing the levels of proinflammatory cytokines and chemokines, and by inducing neutrophil infiltration and apoptosis of tubular epithelial cells. Accordingly, IL-17A may be a novel target in SA-AKI.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-016-0157-1) contains supplementary material, which is available to authorized users.

High-resolution mass spectrometry for exploring metabolic signatures of sepsis-induced acute kidney injury

Sepsis is a commonly encountered scenario in an intensive care unit (ICU), and the kidney is one of the organs frequently affected.