The association of early combined lactate and glucose levels with subsequent renal and liver dysfunction and hospital mortality in critically ill patients

Dysglycaemia in Ebola virus disease: a retrospective analysis from the 2018 to 2020 outbreak

BACKGROUND

Ebola virus disease (EVD) is associated with multisystem organ failure and high mortality. Severe hypoglycaemia is common, life-threatening, and correctable in critically ill patients, but glucose monitoring may be limited in EVD treatment units.

METHODS

We conducted a retrospective review of patients admitted to EVD treatment units in Butembo and Katwa, Eastern DRC. Glucose measurements were done using a handheld glucometer at the bedside or using the Piccolo xpress Chemistry Analyzer on venous samples.

FINDINGS

384 patients (median age 30 years (interquartile range, IQR, 20-45), 57% female) and 6422 glucose measurements (median 11 per patient, IQR 4-22) were included in the analysis. Severe hypoglycaemia (≤2.2 mmol/L) and hyperglycaemia (>10 mmol/L) were recorded at least once during the ETU admission in 97 (25%) and 225 (59%) patients, respectively. A total of 2004 infusions of glucose-containing intravenous solutions were administered to 302 patients (79%) with a median cumulative dose of 175g (IQR 100-411). The overall case fatality rate was 157/384 (41%) and was 2.2-fold higher (95% CI 1.3-3.8) in patients with severe hypoglycaemia than those without hypoglycaemia (p = 0.0042). In a multivariable Cox proportional hazards model, periods of severe hypoglycaemia (adjusted hazard ratio (aHR) 6.2, 95% CI 3.2-12, p < 0.0001) and moderate hypoglycaemia (aHR 3.0, 95% CI 1.9-4.8, p < 0.0001) were associated with elevated mortality.

INTERPRETATION

Hypoglycaemia is common in EVD, requires repeated correction with intravenous dextrose solutions, and is associated with mortality.

FUNDING

This study was not supported by any specific funding.

Metabolomic and lipidomic landscape of porcine kidney associated with kidney perfusion in heart beating donors and donors after cardiac death

Transplant centers are currently facing a lack of tools to ensure adequate evaluation of the quality of the available organs, as well as a significant shortage of kidney donors. Therefore, efforts are being made to facilitate the effective use of available organs and expand the donor pool, particularly with expanded criteria donors. Fulfilling a need, we aim to present an innovative analytical method based on solid-phase microextraction (SPME) - chemical biopsy. In order to track changes affecting the organ throughout the entire transplant procedure, porcine kidneys were subjected to multiple samplings at various time points. The application of small-diameter SPME probes assured the minimal invasiveness of the procedure. Porcine model kidney autotransplantation was executed for the purpose of simulating two types of donor scenarios: donors with a beating heart (HBD) and donors after cardiac death (DCD). All renal grafts were exposed to continuous normothermic ex vivo perfusion. Following metabolomic and lipidomic profiling using high-performance liquid chromatography coupled to a mass spectrometer, we observed differences in the profiles of HBD and DCD kidneys. The alterations were predominantly related to energy and glucose metabolism, and differences in the levels of essential amino acids, purine nucleosides, lysophosphocholines, phosphoethanolamines, and triacylglycerols were noticed. Our results indicate the potential of implementing chemical biopsy in the evaluation of graft quality and monitoring of renal function during perfusion.

Inflammatory liver diseases and susceptibility to sepsis

Patients with inflammatory liver diseases, particularly alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease (MAFLD), have higher incidence of infections and mortality rate due to sepsis. The current focus in the development of drugs for MAFLD is the resolution of non-alcoholic steatohepatitis and prevention of progression to cirrhosis. In patients with cirrhosis or alcoholic hepatitis, sepsis is a major cause of death. As the metabolic center and a key immune tissue, liver is the guardian, modifier, and target of sepsis. Septic patients with liver dysfunction have the highest mortality rate compared with other organ dysfunctions. In addition to maintaining metabolic homeostasis, the liver produces and secretes hepatokines and acute phase proteins (APPs) essential in tissue protection, immunomodulation, and coagulation. Inflammatory liver diseases cause profound metabolic disorder and impairment of energy metabolism, liver regeneration, and production/secretion of APPs and hepatokines. Herein, the author reviews the roles of (1) disorders in the metabolism of glucose, fatty acids, ketone bodies, and amino acids as well as the clearance of ammonia and lactate in the pathogenesis of inflammatory liver diseases and sepsis; (2) cytokines/chemokines in inflammatory liver diseases and sepsis; (3) APPs and hepatokines in the protection against tissue injury and infections; and (4) major nuclear receptors/signaling pathways underlying the metabolic disorders and tissue injuries as well as the major drug targets for inflammatory liver diseases and sepsis. Approaches that focus on the liver dysfunction and regeneration will not only treat inflammatory liver diseases but also prevent the development of severe infections and sepsis.

Exploring the role of antioxidants in sepsis-associated oxidative stress: a comprehensive review

Sepsis is a potentially fatal condition characterized by organ dysfunction caused by an imbalanced immune response to infection. Although an increased inflammatory response significantly contributes to the pathogenesis of sepsis, several molecular mechanisms underlying the progression of sepsis are associated with increased cellular reactive oxygen species (ROS) generation and exhausted antioxidant pathways. This review article provides a comprehensive overview of the involvement of ROS in the pathophysiology of sepsis and the potential application of antioxidants with antimicrobial properties as an adjunct to primary therapies (fluid and antibiotic therapies) against sepsis. This article delves into the advantages and disadvantages associated with the utilization of antioxidants in the therapeutic approach to sepsis, which has been explored in a variety of animal models and clinical trials. While the application of antioxidants has been suggested as a potential therapy to suppress the immune response in cases where an intensified inflammatory reaction occurs, the use of multiple antioxidant agents can be beneficial as they can act additively or synergistically on different pathways, thereby enhancing the antioxidant defense. Furthermore, the utilization of immunoadjuvant therapy, specifically in septic patients displaying immunosuppressive tendencies, represents a promising advancement in sepsis therapy.

Review on Kidney-Liver Crosstalk: Pathophysiology of Their Disorders

Kidney-liver crosstalk plays a crucial role in normal and certain pathological conditions. In pathologic states, both renal-induced liver damage and liver-induced kidney diseases may happen through these kidney-liver interactions. This bidirectional crosstalk takes place through the systemic conditions that mutually influence both the liver and kidneys. Ischemia and reperfusion, cytokine release and pro-inflammatory signaling pathways, metabolic acidosis, oxidative stress, and altered enzyme activity and metabolic pathways establish the base of this interaction between the kidneys and liver. In these concomitant kidney-liver diseases, the survival rates strongly correlate with early intervention and treatment of organ dysfunction. Proper care of a nephrologist and hepatologist and the identification of pathological conditions using biomarkers at early stages are necessary to prevent the complications induced by this complex and potentially vicious cycle. Therefore, understanding the characteristics of this crosstalk is essential for better management. In this review, we discussed the available literature concerning the detrimental effects of kidney failure on liver functions and liver-induced kidney diseases.

High Glucose Levels Promote Switch to Synthetic Vascular Smooth Muscle Cells via Lactate/GPR81

Hyperglycemia, lipotoxicity, and insulin resistance are known to increase the secretion of extracellular matrix from cardiac fibroblasts as well as the activation of paracrine signaling from cardiomyocytes, immune cells, and vascular cells, which release fibroblast-activating mediators. However, their influences on vascular smooth muscle cells (vSMCs) have not been well examined. This study aimed to investigate whether contractile vascular vSMCs could develop a more synthetic phenotype in response to hyperglycemia. The results showed that contractile and synthetic vSMCs consumed high glucose in different ways. Lactate/GPR81 promotes the synthetic phenotype in vSMCs in response to high glucose levels. The stimulation of high glucose was associated with a significant increase in fibroblast-like features: synthetic vSMC marker expression, collagen 1 production, proliferation, and migration. GPR81 expression is higher in blood vessels in diabetic patients and in the high-glucose, high-lipid diet mouse. The results demonstrate that vSMCs assume a more synthetic phenotype when cultured in the presence of high glucose and, consequently, that the high glucose could trigger a vSMC-dependent cardiovascular disease mechanism in diabetes via lactate/GPR81.

The relationship between hyperglycaemia on admission and patient outcome is modified by hyperlactatemia and diabetic status: a retrospective analysis of the eICU collaborative research database

Both blood glucose and lactate are well-known predictors of organ dysfunction and mortality in critically ill patients. Previous research has shown that concurrent adjustment for glucose and lactate modifies the relationship between these variables and patient outcomes, including blunting of the association between blood glucose and patient outcome. We aim to investigate the relationship between ICU admission blood glucose and hospital mortality while accounting for lactate and diabetic status. Across 43,250 ICU admissions, weighted to account for missing data, we assessed the predictive ability of several logistic regression and generalised additive models that included blood glucose, blood lactate and diabetic status. We found that inclusion of blood glucose marginally improved predictive performance in all patients: AUC-ROC 0.665 versus 0.659 (p = 0.005), with a greater degree of improvement seen in non-diabetics: AUC-ROC 0.675 versus 0.663 (p < 0.001). Inspection of the estimated risk profiles revealed the standard U-shaped risk profile for blood glucose was only present in non-diabetic patients after controlling for blood lactate levels. Future research should aim to utilise observational data to estimate whether interventions such as insulin further modify this effect, with the goal of informing future RCTs of interventions targeting glycaemic control in the ICU.

Independent risk factors of acute kidney injury among patients receiving extracorporeal membrane oxygenation

OBJECTIVE

Acute kidney injury (AKI) is one of the most frequent complications in patients treated with extracorporeal membrane oxygenation (ECMO) support. The aim of this study was to investigate the risk factors of AKI in patients undergoing ECMO support.

METHODS

We performed a retrospective cohort study which included 84 patients treated with ECMO support at intensive care unit in the People's Hospital of Guangxi Zhuang Autonomous Region from June 2019 to December 2020. AKI was defined as per the standard definition proposed by the Kidney Disease Improving Global Outcome (KDIGO). Independent risk factors for AKI were evaluated through multivariable logistic regression analysis with stepwise backward approach.

RESULTS

Among the 84 adult patients, 53.6% presented AKI within 48 h after initiation of ECMO support. Three independent risk factors of AKI were identified. The final logistic regression model included: left ventricular ejection fraction (LVEF) before ECMO initiation (OR, 0.80; 95% CI, 0.70-0.90), sequential organ failure assessment (SOFA) score before ECMO initiation (OR, 1.41; 95% CI, 1.16-1.71), and serum lactate at 24 h after ECMO initiation (OR, 1.27; 95% CI, 1.09-1.47). The area under receiver operating characteristics of the model was 0.879.

CONCLUSION

Severity of underlying disease, cardiac dysfunction before ECMO initiation and the blood lactate level at 24 h after ECMO initiation were independent risk factors of AKI in patients who received ECMO support.

Lactate level and lactate clearance for acute kidney injury prediction among patients admitted with ST-segment elevation myocardial infarction: A retrospective cohort study

Background

Hyperlactatemia is a prognostic marker among patients with ST-segment elevation acute myocardial infarction (STEMI). However, the predictive value of lactate and the dynamic change associated with acute kidney injury (AKI) among patients with STEMI, remain poorly understood. We aimed to compare single lactate values at admission (Lac_adm) and 12 h after admission (Lac_12h) with lactate clearance (LC) 12 h after admission for AKI prediction in patients with STEMI.

Methods

A total of 1,784 patients with STEMI were included. The study endpoint was AKI occurrence during hospitalization. The predictive value of lactate levels measured at admission and 12 h after admission and LC for AKI prediction was determined using multivariate logistic regression analyses and compared with receiver operator characteristic (ROC) curve analysis.

Results

Overall, AKI was observed in 353 (19.8%) patients. In multivariate logistic regression analyses, Lac_adm ≥ 4.3 mmol/L (OR: 1.53; 95% CI: 1.01–2.30), Lac_12h ≥ 2.1 mmol/L (OR: 1.81; 95% CI: 1.36–2.42), and LC ≥ −7.5% (OR: 0.40; 95% CI: 0.30–0.53) were the independent predictive factors for AKI after adjusting for confounders. ROC curve analysis results revealed that Lac_12h (0.639; 95% CI: 0.616–0.661) exhibited a significantly higher area under the curve (AUC) than those of Lac_adm (0.551; 95% CI: 0.527–0.574) and LC (0.593; 95% CI: 0.570–0.616) in the prediction of AKI. LC (_△AUC = 0.037, p < 0.001) and Lac_12h (_△AUC = 0.017, p = 0.029) enhanced the discrimination capacity of Mehran Risk Score (MRS) for AKI among patients undergoing emergency coronary angiography.

Conclusion

Lac_12h is more effective for AKI prediction among patients with STEMI than Lac_adm and LC. Furthermore, Lac_12h and LC enhance the prediction capacity of MRS for AKI among patients after emergency coronary angiography.

The Pyruvate Dehydrogenase Complex Mitigates LPS-Induced Endothelial Barrier Dysfunction by Metabolic Regulation

ABSTRACT

Sepsis is a fatal health issue induced by an aberrant host response to infection, and it correlates with organ damage and a high mortality rate. Endothelial barrier dysfunction and subsequent capillary leakage play major roles in sepsis-induced multiorgan dysfunction. Anaerobic glycolysis is the primary metabolic mode in sepsis and the pyruvate dehydrogenase complex (PDHC) serves as a critical hub in energy regulation. Therefore, it is important to understand the role of PDHC in metabolic regulation during the development of sepsis-induced endothelial barrier dysfunction.In present study, human umbilical vein endothelial cells (HUVECs) and C57 BL/6 mice were treated with lipopolysaccharide (LPS) as models of endotoxemia. LPS increased basal glycolysis, compensatory glycolysis, and lactate secretion, indicating increased glycolysis level in endothelial cells (ECs). Activation of PDHC with dichloroacetate (DCA) reversed LPS-induced glycolysis, allowing PDHC to remain in the active dephosphorylated state, thereby preventing lactic acid production and HUVECs monolayers barrier dysfunction, as assessed by transendothelial electrical resistance and Fluorescein Isothiocyanate-labeled dextran. The in vivo study also showed that the lactate level and vascular permeability were increased in LPS-treated mice, but pretreatment with DCA attenuated these increases. The LPS-treated HUVEC model showed that DCA reversed LPS-induced phosphorylation of pyruvate dehydrogenase E1α Ser293 and Ser300 to restore PDHC activity. Immunoprecipitation results showed that LPS treatment increased the acetylation level of PDH E1α in HUVECs.Our study suggested that activation of PDHC may represent a therapeutic target for treatment of LPS-induced endothelial barrier dysfunction.

Real-Time Monitoring of Blood Parameters in the Intensive Care Unit: State-of-the-Art and Perspectives

The number of patients in intensive care units has increased over the past years. Critically ill patients are treated with a real time support of the instruments that offer monitoring of relevant blood parameters. These parameters include blood gases, lactate, and glucose, as well as pH and temperature. Considering the COVID-19 pandemic, continuous management of dynamic deteriorating parameters in patients is more relevant than ever before. This narrative review aims to summarize the currently available literature regarding real-time monitoring of blood parameters in intensive care. Both, invasive and non-invasive methods are described in detail and discussed in terms of general advantages and disadvantages particularly in context of their use in different medical fields but especially in critical care. The objective is to explicate both, well-known and frequently used as well as relatively unknown devices. Furtehrmore, potential future direction in research and development of realtime sensor systems are discussed. Therefore, the discussion section provides a brief description of current developments in biosensing with special emphasis on their technical implementation. In connection with these developments, the authors focus on different electrochemical approaches to invasive and non-invasive measurements in vivo.

Prognostic Factors of Patients with Stercoral Perforation of the Colon

Background/Aims

The incidence of stercoral perforation of the colon (SPC) is expected to rise, given the increased life expectancy and the aging population. On the other hand, the prognostic factors of mortality after surgery for SPC remain unclear. This study examined the prognostic factors of patients with SPC after surgery.

Methods

The medical records of 145 patients who underwent surgery for colonic perforation between April 2010 and May 2019 were reviewed retrospectively. In 145 patients, 22 patients who underwent SPC surgery were categorized into the following two groups according to in-hospital survival after surgery: alive (group A, n=15) and dead (group B, n=7).

Results

In all enrolled patients, the mean age was 75.7±9.0 years, with a female predominance (female patients, n=19, 86.4%). Sixteen patients (72.7%) had chronic constipation with medications, and five patients (22.7%) were bedridden. The rate of preoperative bedridden status was significantly higher in group B than group A (6.7% vs. 57.1%; p=0.021). Univariate analysis revealed immobility, a sequential organ failure assessment (SOFA) score, and lactate levels of more than 2.0 mmol/L to be factors associated with increased mortality rates in the postoperative period. Multivariate analysis revealed abnormal lactate levels to be the only factor related to mortality (hazard ratio 16.50, 95% CI 1.48-183.07, p=0.022).

Conclusions

Preoperative abnormal serum lactate levels may be a risk factor for mortality after surgery in patients with stercoral perforation. Further research will be needed to identify the postoperative prognostic SPC factors.

Nutritional Management of the Critically Ill Neonate: A Position Paper of the ESPGHAN Committee on Nutrition

OBJECTIVES

The nutritional management of critically ill term neonates and preterm infants varies widely, and controversies exist in regard to when to initiate nutrition, mode of feeding, energy requirements, and composition of enteral and parenteral feeds. Recommendations for nutritional support in critical illness are needed.

METHODS

The ESPGHAN Committee on Nutrition (ESPGHAN-CoN) conducted a systematic literature search on nutritional support in critically ill neonates, including studies on basic metabolism. The Medline database and the Cochrane Library were used in the search for relevant publications. The quality of evidence was reviewed and discussed before voting on recommendations, and a consensus of 90% or more was required for the final approval. Important research gaps were also identified.

RESULTS

This position paper provides clinical recommendations on nutritional support during different phases of critical illness in preterm and term neonates based on available literature and expert opinion.

CONCLUSION

Basic research along with adequately powered trials are urgently needed to resolve key uncertainties on metabolism and nutrient requirements in this heterogeneous patient population.

Energetic dysfunction in sepsis: a narrative review

Background

Growing evidence associates organ dysfunction(s) with impaired metabolism in sepsis. Recent research has increased our understanding of the role of substrate utilization and mitochondrial dysfunction in the pathophysiology of sepsis-related organ dysfunction. The purpose of this review is to present this evidence as a coherent whole and to highlight future research directions.

Main text

Sepsis is characterized by systemic and organ-specific changes in metabolism. Alterations of oxygen consumption, increased levels of circulating substrates, impaired glucose and lipid oxidation, and mitochondrial dysfunction are all associated with organ dysfunction and poor outcomes in both animal models and patients. The pathophysiological relevance of bioenergetics and metabolism in the specific examples of sepsis-related immunodeficiency, cerebral dysfunction, cardiomyopathy, acute kidney injury and diaphragmatic failure is also described.

Conclusions

Recent understandings in substrate utilization and mitochondrial dysfunction may pave the way for new diagnostic and therapeutic approaches. These findings could help physicians to identify distinct subgroups of sepsis and to develop personalized treatment strategies. Implications for their use as bioenergetic targets to identify metabolism- and mitochondria-targeted treatments need to be evaluated in future studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00893-7.

The Prognostic Usefulness of the Lactate/Albumin Ratio for Predicting Clinical Outcomes in Out-of-Hospital Cardiac Arrest: a Prospective, Multicenter Observational Study (koCARC) Study

BACKGROUND AND PURPOSE

We aimed to evaluate the lactate/albumin ratio (LAR) to identify its significance as a prognostic marker for favorable neurologic outcome and survival in patients with return of spontaneous circulation after out-of-hospital cardiac arrest (OHCA). Based on the LAR and multiple parameters, we developed new nomograms and externally validated the tools.

METHODS

We conducted an observational study using a prospective, multicenter registry of out-of-cardiac arrest resuscitation provided by the Korean Cardiac Arrest Research Consortium registry from October 2015 to June 2017.

RESULTS

A total of 524 patients were included in this study. An increased LAR was significantly associated with decreased favorable neurologic outcomes (odds ratio [OR] 0.787; 95% confidence interval [CI], 0.630-0.983; P = 0.035) and survival at discharge (OR 0.744; 95% CI, 0.638-0.867; P < 0.001). The areas under the curve (AUCs) for predicting neurologic outcome and survival to discharge using the LAR were 0.824 (P < 0.001) and 0.781 (P < 0.001), respectively. An LAR value of more than the optimal cutoff values of 2.82 and 3.62 could significantly improve prediction of decreased favorable neurologic outcome and survival to discharge, respectively. We constructed nomograms based on the multivariate logistic model. The model for predicting favorable neurologic outcomes and survival discharge had AUCs of 0.927 (P < 0.001) and 0.872 (P < 0.001), respectively.

CONCLUSION

The prognostic performance of the LAR was superior to a single measurement of lactate for predicting favorable neurologic outcomes and survival to discharge after OHCA. The newly developed nomograms can provide rapid prediction of probability of clinical outcomes.

Admission Serum Bicarbonate Predicts Adverse Clinical Outcomes in Hospitalized Cirrhotic Patients

A low serum bicarbonate (SB) level is predictive of adverse outcomes in kidney injury, infection, and aging. Because the liver plays an important role in acid-base homeostasis and lactic acid metabolism, we speculated that such a relationship would exist for patients with cirrhosis. To assess the prognostic value of admission SB on adverse hospital outcomes, clinical characteristics were extracted and analyzed from a large electronic health record system. Patients were categorized based on admission SB (mEq/L) into 7 groups based on the reference range (22-25) into mildly (18-21), moderately (14-17), and severely (<14) decreased groups and mildly (26-29), moderately (30-33), and severely (>30) increased groups, and the relationship of SB category with the frequency of complications (acute kidney injury/hepatorenal syndrome, portosystemic encephalopathy, gastrointestinal bleeding, ascites, and spontaneous bacterial peritonitis) and hospital metrics (length of stay [LOS], admission to an intensive care unit [ICU], and mortality) was assessed. A total of 2,693 patients were analyzed. Mean SB was 22.9 ± 4.5 mEq/L. SB was within the normal range (22-25 mEq/L) in 1,072 (39.8%) patients, and 955 patients (36%) had a low SB. As the SB category decreased, the incidence of complications progressively increased (p < 0.001). Increased MELD-Na score and low serum albumin also correlated with frequency of complications (p < 0.001). As the SB category decreased, LOS, ICU admission, and mortality progressively increased (p < 0.001). On multivariate analysis, the association of decreased SB with higher odds of complications, LOS, ICU admission, and mortality persisted. Conclusion. Low admission SB in patients with cirrhosis is associated with cirrhotic complications, longer LOS, increased ICU admissions, and increased hospital mortality.

Early lactate and glucose kinetics following return to spontaneous circulation after out-of-hospital cardiac arrest

Objective

Lactate has been shown to be preferentially metabolized in comparison to glucose after physiological stress, such as strenuous exercise. Derangements of lactate and glucose are common after out-of-hospital cardiac arrest (OHCA). Therefore, we hypothesized that lactate decreases faster than glucose after return-to-spontaneous-circulation (ROSC) after OHCA.

Results

We included 155 OHCA patients in our analysis. Within the first 8 h of presentation to the emergency department, 843 lactates and 1019 glucoses were available, respectively. Lactate decreased to 50% of its initial value within 1.5 h (95% CI [0.2–3.6 h]), while glucose halved within 5.6 h (95% CI [5.4–5.7 h]). Also, in the first 8 h after presentation lactate decreases more than glucose in relation to their initial values (lactate 72.6% vs glucose 52.1%). In patients with marked hyperlactatemia after OHCA, lactate decreased expediently while glucose recovered more slowly, whereas arterial pH recovered at a similar rapid rate as lactate. Hospital non-survivors (N = 82) had a slower recovery of lactate (P = 0.002) than survivors (N = 82). The preferential clearance of lactate underscores its role as a prime energy substrate, when available, during recovery from extreme stress.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05604-w.

Renal gluconeogenesis: an underestimated role of the kidney in systemic glucose metabolism

Glucose levels are tightly regulated at all times. Gluconeogenesis is the metabolic pathway dedicated to glucose synthesis from non-hexose precursors. Gluconeogenesis is critical for glucose homoeostasis, particularly during fasting or stress conditions. The renal contribution to systemic gluconeogenesis is increasingly recognized. During the post-absorptive phase, the kidney accounts for ∼40% of endogenous gluconeogenesis, occurring mainly in the kidney proximal tubule. The main substrate for renal gluconeogenesis is lactate and the process is regulated by insulin and cellular glucose levels, but also by acidosis and stress hormones. The kidney thus plays an important role in the maintenance of glucose and lactate homoeostasis during stress conditions. The impact of acute and chronic kidney disease and proximal tubular injury on gluconeogenesis is not well studied. Recent evidence shows that in both experimental and clinical acute kidney injury, impaired renal gluconeogenesis could significantly participate in systemic metabolic disturbance and thus alter the prognosis. This review summarizes the biochemistry of gluconeogenesis, the current knowledge of kidney gluconeogenesis, its modifications in kidney disease and the clinical relevance of this fundamental biological process in human biology.

Altered proximal tubular cell glucose metabolism during acute kidney injury is associated with mortality

Acute kidney injury (AKI) is strongly associated with mortality, independently of its cause. The kidney contributes to up to 40% of systemic glucose production by gluconeogenesis during fasting and under stress conditions. Whether kidney gluconeogenesis is impaired during AKI and how this might influence systemic metabolism remain unknown. Here we show that glucose production and lactate clearance are impaired during human and experimental AKI by using renal arteriovenous catheterization in patients, lactate tolerance testing in mice and glucose isotope labelling in rats. Single-cell transcriptomics reveal that gluconeogenesis is impaired in proximal tubule cells during AKI. In a retrospective cohort of critically ill patients, we demonstrate that altered glucose metabolism during AKI is a major determinant of systemic glucose and lactate levels and is strongly associated with mortality. Thiamine supplementation increases lactate clearance without modifying renal function in mice with AKI, enhances glucose production by renal tubular cells ex vivo and is associated with reduced mortality and improvement of the metabolic pattern in a retrospective cohort of critically ill patients with AKI. This study highlights an unappreciated systemic role of renal glucose and lactate metabolism under stress conditions, delineates general mechanisms of AKI-associated mortality and introduces a potential intervention targeting metabolism for a highly prevalent clinical condition with limited therapeutic options.

Metabolic Parameters Influence Brain Infarction and Outcome after Resection of Brain Metastases

Perioperative infarction in brain tumor surgery occurs in about 30-80% of cases and is strongly associated with poor patient outcomes and longer hospital stays. Risk factors contributing to postoperative brain infarction should be assessed. We retrospectively included all patients who underwent surgery for brain metastases between January 2015 and December 2017. Hemodynamic parameters were analyzed and then correlated to postoperative infarct volume and overall survival. Of 249 patients who underwent biopsy or resection of brain metastases during that time, we included 234 consecutive patients in this study. In total, 172/249 patients showed ischemic changes in postoperative magnet resonance imaging (MRI) (73%). Independent risk factors for postoperative brain infarction were perioperative blood loss (rho 0.189, p = 0.00587), blood glucose concentration (rho 0.206, p = 0.00358), blood lactate concentration (rho 0.176; p = 0.0136) and cumulative time of reduced PaCO₂ (rho -0.142; p = 0.0445). Predictors for reduced overall survival were blood lactate (p = 0.007) and blood glucose levels (p = 0.032). Other hemodynamic parameters influenced neither infarct volume, nor overall survival. Intraoperative elevated lactate and glucose levels are independently associated with postoperative brain infarction in surgery of brain metastases. Furthermore, they might predict reduced overall survival after surgery. Blood loss during surgery also leads to more cerebral ischemic changes. Close perioperative monitoring of metabolism might reduce those complications.

Initially elevated arterial lactate as an independent predictor of poor outcomes in severe acute pancreatitis

BACKGROUND

The present study aimed to investigate the relationships between arterial lactate levels and outcomes in severe acute pancreatitis.

METHODS

The study retrospectively analyzed the medical data of 329 patients with severe acute pancreatitis from January 2014 to February 2019. We compared baseline characteristics, laboratory data, severity scores, types of persistent organ failure, and primary and secondary outcomes of patients with and without elevated arterial lactate levels at admission. A multivariate logistic regression analysis model and receiver operating characteristic curve were adopted to evaluate the value of arterial lactate ≥4 mmol/L for identifying high-risk patients. Trends in arterial lactate levels were compared between patients in the survivor and nonsurvivor groups over a period of 7 days.

RESULTS

Compared to normal arterial lactate levels, patients with elevated arterial lactate levels show significantly higher incidences of multiple persistent organ failure (3% vs 30%, P < 0.01), death (2% vs 11%, P < 0.01), septic shock (4% vs 24%, P < 0.01), pancreatic infection (12% vs 37%, P < 0.01), abdominal compartment syndrome (3% vs 20%, P < 0.01), pancreatic necrosis (41% vs 63%, P < 0.01), and a need for ventilator support (26% vs 54%, P < 0.01). For predicting mortality, arterial lactate levels ≥4 mmol/L had a high hazard ratio (10, 95% CI; 3.7-27; P < 0.01) and the highest area under the curve (0.78).

CONCLUSIONS

Our results indicate that initially elevated arterial lactate is independently associated with poor outcomes and death in patients with severe acute pancreatitis and may serve as an early high-risk stratification indicator.

Advances in Medical Nutrition Therapy: Parenteral Nutrition

Parenteral nutrition has evolved tremendously, with parenteral formulas now safer and more accessible than ever. "All-in-one" admixtures are now available, which simplify parenteral nutrition usage and decrease line infection rates alongside other methods of infectious control. Recently published data on the benefits of parenteral nutrition versus enteral nutrition together with the widespread use of indirect calorimetry solve many safety issues that have emerged over the years. All these advances, alongside a better understanding of glycemic control and lipid and protein formulation improvements, make parenteral nutrition a safe alternative to enteral nutrition.

Clinical examination findings as predictors of acute kidney injury in critically ill patients

BACKGROUND

Acute Kidney Injury (AKI) in critically ill patients is associated with a markedly increased morbidity and mortality. The aim of this study was to establish the predictive value of clinical examination for AKI in critically ill patients.

METHODS

This was a sub-study of the SICS-I, a prospective observational cohort study of critically ill patients acutely admitted to the Intensive Care Unit (ICU). Clinical examination was performed within 24 hours of ICU admission. The occurrence of AKI was determined at day two and three after admission according to the KDIGO definition including serum creatinine and urine output. Multivariable regression modeling was used to assess the value of clinical examination for predicting AKI, adjusted for age, comorbidities and the use of vasopressors.

RESULTS

A total of 1003 of 1075 SICS-I patients (93%) were included in this sub-study. 414 of 1003 patients (41%) fulfilled the criteria for AKI. Increased heart rate (OR 1.12 per 10 beats per minute increase, 98.5% CI 1.04-1.22), subjectively cold extremities (OR 1.52, 98.5% CI 1.07-2.16) and a prolonged capillary refill time on the sternum (OR 1.89, 98.5% CI 1.01-3.55) were associated with AKI. This multivariable analysis yielded an area under the receiver-operating curve (AUROC) of 0.70 (98.5% CI 0.66-0.74). The model performed better when lactate was included (AUROC of 0.72, 95%CI 0.69-0.75), P = .04.

CONCLUSION

Clinical examination findings were able to predict AKI with moderate accuracy in a large cohort of critically ill patients. Findings of clinical examination on ICU admission may trigger further efforts to help predict developing AKI.

The Impact of Serum Glucose on the Predictive Value of Serum Lactate for Hospital Mortality in Critically Ill Surgical Patients

Background

Lactate has been widely used as a risk indicator of outcomes in critically ill patients due to its ready measurement and good predictive ability. However, the interconnections between lactate metabolism and glucose metabolism have not been sufficiently explored, yet. In this study, we aimed to investigate whether glucose levels could influence the predictive ability of lactate and design a more comprehensive strategy to assess the in-hospital mortality of critically ill patients.

Methods

We analyzed the clinical data of 293 critically ill patients. The primary outcome was in-hospital mortality. The logistic regression analysis and the area under the receiver operating characteristic curve (AUROC) were applied to evaluate the predictive ability of lactate in association with glucose.

Results

The lactate level showed significant association with in-hospital mortality, and its predictive ability was also comparable to other prognostic scores such as the SOFA score and APACHE II score. We further divided 293 patients into three groups based on glucose levels: low-glucose group (<7 mmol/L), medium-glucose group (7-9 mmol/L), and high-glucose group (>9 mmol/L). The lactate level was associated with in-hospital mortality in the low- and high- glucose groups, but not in the medium-glucose group, whereas the SOFA score and APACHE II score were associated with in-hospital mortality in all three glucose groups. The AUROC of lactate in the medium-glucose group was also the lowest among the three glucose groups, indicating a decrease in its predictive ability.

Conclusions

Our findings demonstrated that the predictive ability of lactate to assess in-hospital mortality could be influenced by glucose levels. In the medium glucose level (i.e., 7-9 mmol/L), lactate was inadequate to predict in-hospital mortality and the SOFA score; the APACHE II score should be utilized as a complementation in order to obtain a more accurate prediction.

Updates in Glycemic Management in the Hospital

PURPOSE OF REVIEW

To provide an update of glycemic management during metabolic stress related to surgery or critical illness.

RECENT FINDINGS

There is a clear association between severe hyperglycemia, hypoglycemia, and high glycemic variability and poor outcomes of postoperative or critically ill patients. However, the impressive beneficial effects of tight glycemic management (TGM) by intensive insulin therapy reported in one study were never reproduced. Hence, the recommendation of TGM is now replaced by more liberal blood glucose (BG) targets (< 180 mg/dL or 10 mM). Recent data support the concept of targeting individualized blood glucose (BG) values according to the presence of diabetes mellitus/chronic hyperglycemia, the presence of brain injury, and the time from injury. A more liberal glycemic management goal is currently advised during metabolic stress and could be switched to individualized glycemic management once validated by prospective trials.

Lactate and number of organ failures predict intensive care unit mortality in patients with acute-on-chronic liver failure

BACKGROUND AND AIMS

Patients with acute-on-chronic liver failure (ACLF) have high mortality rates. Most prognostic scores were not developed for the intensive care unit (ICU) setting. We aimed to improve risk stratification for patients with ACLF in the ICU.

METHODS

A training set with 240 patients with cirrhosis and organ failures (Chronic Liver Failure Sequential Organ Failure Assessment score [CLIF-SOFA]) from Curry Cabral Hospital (Portugal) and University of Alberta Hospital (Canada) in 2010-2016 was used to derive a prognostic model for ICU mortality. A validation set with 237 patients with cirrhosis and organ failures from Vancouver General Hospital (Canada) in 2000-2011 was used to evaluate its performance.

RESULTS

Amongst patients in the training set, ICU and hospital mortality rates were 39.2% and 54.6% respectively. Median lactate (4.4 vs 2.5 mmol/L) and number of organ failures (3 vs 2) on admission to ICU were associated with higher likelihood of ICU mortality (P < 0.001 for both). The lactate and organ failures predictive model (LacOF) was derived to predict ICU mortality: -2.420 + 0.072 × lactate + 0.569 × number of organ failures (area under-the-curve [AUC], 0.76). In the validation set, the LacOF model discriminative ability (AUC, 0.85) outperformed the CLIF-SOFA (AUC, 0.79), Chronic Liver Failure Consortium Acute-on-Chronic Liver Failure (AUC, 0.73), Model for End-stage Liver Disease score (AUC, 0.78) and Acute Physiology and Chronic Health Evaluation II scores (AUC, 0.74; P < 0.05 for all). The LacOF model calibration was good up to the 25% likelihood of ICU mortality.

CONCLUSIONS

In patients with ACLF, lactate and number of organ failures on admission to ICU are useful to predict ICU mortality. This early prognostic evaluation may help to better stratify the risk of ICU mortality and thus optimize organ support strategies.

Change in alkaline phosphatase activity associated with intensive care unit and hospital length of stay in patients with septic acute kidney injury on continuous renal replacement therapy

Background

Evidence suggests that alkaline phosphatase attenuates inflammatory response in sepsis by lipopolysaccharide detoxification and adenosine triphosphate dephosphorylation. We sought to determine changes in alkaline phosphatase (AP) activity during septic acute kidney injury (AKI) and clinical parameters associated with AP activity.

Methods

In this retrospective study, we investigated baseline (when initiating CRRT) and follow-up AP activity on day 3, and associated outcomes in patients who underwent continuous renal replacement therapy (CRRT) due to septic AKI.

Results

We analyzed the baseline AP activity of 155 patients and day 3 AP activity in 123 patients. Baseline AP activity was not associated with renal or inflammatory biomarkers, or outcomes. It did not significantly differ between the 75 survivors and 80 non-survivors (p = 0.155). AP activity was higher on day 3 than at baseline (105 U/L [interquartile range, 79–156] vs 90 U/L [interquartile range, 59–133]). In particular, liver and bone isoforms increased significantly (p < 0.05), but intestine isoforms did not reach statistical significance (p = 0.367). In addition, day 3 AP activity showed a weak correlation with length of ICU stay (r = 0.213, p = 0.018) and length of hospital stay (r = 0.216, p = 0.017), but not with survival (r = − 0.035, p = 0.698).

Conclusion

Endogenous AP activity significantly increased in patients with septic AKI. However, neither baseline nor follow-up AP activity was associated with survival.

Cystathionine-γ-lyase expression is associated with mitochondrial respiration during sepsis-induced acute kidney injury in swine with atherosclerosis

Background

Sepsis is associated with disturbed glucose metabolism and reduced mitochondrial activity and biogenesis, ultimately leading to multiple organ dysfunction, e.g., acute kidney injury (AKI). Cystathionine-γ-lyase (CSE), the major cardiovascular source of endogenous H₂S release, is implicated in the regulation of glucose metabolism and mitochondrial activity through a PGC1α-dependent mechanism, and critical for kidney function. Atherosclerosis is associated with mitochondrial dysfunction and reduced CSE expression. Thus, the aim of this post hoc study was to test the hypothesis whether there is an interplay between CSE expression and kidney dysfunction, mitochondrial activity, and oxidative/nitrosative stress in porcine septic AKI with underlying coronary artery disease.

Methods

This study is a post hoc analysis of material from anesthetized and instrumented swine with a high fat diet-induced hypercholesterolemia and atherosclerosis undergoing faecal peritonitis-induced septic shock or sham procedure and intensive care (comprising fluid resuscitation and continuous i.v. noradrenaline (NoA) infusion) for 24 h. Glucose metabolism was quantified from blood ¹³C₆-glucose and expiratory ¹³CO₂/¹²CO₂ isotope enrichment during ¹³C₆-glucose infusion. Mitochondrial activity was determined by high-resolution respirometry. CSE and PGC1α expression, as well as nitrotyrosine formation and albumin extravasation, were quantified by immunohistochemistry of formalin-fixed kidney paraffin sections.

Results

Sepsis was associated with lactic acidosis (p = 0.004) and AKI (50% fall of creatinine clearance (CrCl), p = 0.019). While both whole-body glucose production (p = 0.004) and oxidation (p = 0.006) were increased, kidney tissue mitochondrial respiration was reduced (p = 0.028), coinciding with decreased CSE (p = 0.003) and PGC1α (p = 0.003) expression. Albumin extravasation (p = 0.011) and nitrotyrosine formation (p = 0.008) were increased in septic kidneys.

Conclusions

Sepsis-induced AKI is associated with disturbed mitochondrial respiration and biogenesis, which may be aggravated by oxidative and nitrosative stress. Our results confirm previous data in murine septic shock and porcine hemorrhage and resuscitation on the crucial role of CSE for barrier integrity and kidney function.

Electronic supplementary material

The online version of this article (10.1186/s40635-018-0208-z) contains supplementary material, which is available to authorized users.

Addition of lactic acid levels improves the accuracy of quick sequential organ failure assessment in predicting mortality in surgical patients with complicated intra-abdominal infections: a retrospective study

Background

The quick sequential organ failure assessment (qSOFA) alone has a poor sensitivity for predicting mortality in patients with complicated intra-abdominal infections, and plasma lactate levels have been shown to have a strong association with mortality in critically ill patients. Therefore, this study aimed to compare the performance of qSOFA with a score derived from a combination of qSOFA and serum lactate levels for predicting mortality in surgical patients with complicated intra-abdominal infections.

Methods

This retrospective study was performed at a university hospital. The medical records of 457 patients who presented to the emergency department (ED) between January 2008 and December 2016 and required emergency gastrointestinal surgery for a complicated intra-abdominal infection were reviewed retrospectively. qSOFA criteria, sequential organ failure assessment (SOFA) scores, and plasma lactate levels during their ED stay were collected. We performed area under receiver operating characteristic (AUROC) curve and sensitivity analysis to compare the performance of qSOFA alone with that of a score derived from the use of a combination of the qSOFA and lactate levels for predicting patient mortality.

Results

Fifty patients (10.9%) died during hospitalization. The combined qSOFA and lactate level score was superior to qSOFA alone (AUROC = 0.754 vs. 0.717, p = 0.039, respectively) and comparable to the full SOFA score (AUROC = 0.754 vs. 0.795, p = 0.127, respectively) in predicting mortality. Sensitivity and specificity of qSOFA alone were 46 and 86%, respectively, and those of the combined score were 72 and 73%, respectively (p < 0.001).

Conclusion

A score derived from the qSOFA and serum lactate levels had better predictive performance with higher sensitivity than the qSOFA alone in predicting mortality in patients with complicated intra-abdominal infections and had a comparable predictive performance to that of the full SOFA score.