Lactate and glucose metabolism in severe sepsis and cardiogenic shock

Conservative fluid resuscitation protocol does not reduce the incidence of reoperation for bleeding after emergency CABG

Reoperation for bleeding (ROB) after emergency coronary artery bypass grafting (eCABG) has been identified as an independent risk factor for mortality. Consecutively, the influence of fluid intake, fluid output, fluid balance, blood loss, and inotropic demand on ROB were analyzed. This retrospective single-center study included 265 patients undergoing eCABG between 2011 and 2020. From 2018, postoperative hemodynamic management was performed with lower volume administration and higher vasoactive support. The primary outcome measure was the incidence of ROB within 48 h according to altered fluid resuscitation strategy. Consecutively, the influence of fluid intake, fluid output, fluid balance, blood loss, and inotropic demand on ROB were analyzed. Incidence of ROB was independent from the volume resuscitation protocol (P = .3). The ROB group had a higher perioperative risk, which was observed in EuroSCORE II. Fluid intake (P = .021), fluid balance (P = .001), and norepinephrine administration (P = .004) were associated with ROB. Fluid output and blood loss were not associated with ROB (P = .22). Post-test probability was low among all variables. Although fluid management might have an impact on specific postoperative complications, different fluid resuscitation protocols did not alter the incidence of ROB after emergency CABG.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov registration number NCT04533698; date of registration: August 31, 2020 (retrospectively registered due to nature of the study); URL: https://classic.

CLINICALTRIALS

gov/ct2/show/NCT04533698.

The glycemic gap as a prognostic indicator in cardiogenic shock: a retrospective cohort study

BACKGROUND

Stress-induced hyperglycemia (SIH) is associated with poor outcomes in cardiogenic shock (CS), and there have been inconsistent results among patients with or without diabetes mellitus (DM). The glycemic gap (GG) is derived by subtracting A1c-derived average glucose from blood glucose levels; it is a superior indicator of SIH. We aimed to explore the role of GG in the outcomes of patients with CS.

METHODS

Data on patients diagnosed with CS were extracted from the MIMIC-IV v2.0 database to investigate the relationship between GG and 30-day mortality (Number of absolute GG subjects = 359; Number of relative GG subjects = 357). CS patients from the Second Affiliated Hospital of Wenzhou Medical University were enrolled to explore the correlation between GG and lactic acid (Number of absolute GG subjects = 252; Number of relative GG subjects = 251). Multivariate analysis, propensity score-matched (PSM) analysis, inverse probability treatment weighting (IPTW), and Pearson correlation analysis were applied.

RESULTS

Absolute GG was associated with 30-day all-cause mortality in CS patients (HRadjusted: 1.779 95% CI: 1.137-2.783; HRPSM: 1.954 95% CI: 1.186-3.220; HRIPTW: 1.634 95% CI: 1.213-2.202). The higher the absolute GG level, the higher the lactic acid level (βadjusted: 1.448 95% CI: 0.474-2.423). A similar trend existed in relative GG (HRadjusted: 1.562 95% CI: 1.003-2.432; HRPSM: 1.790 95% CI: 1.127-2.845; HRIPTW: 1.740 95% CI: 1.287-2.352; βadjusted:1.294 95% CI: 0.369-2.219). Subgroup analysis showed that the relationship existed irrespective of DM. The area under the curve of GG combined with the Glasgow Coma Scale (GCS) for 30-day all-cause mortality was higher than that of GCS (absolute GG: 0.689 vs. 0.637; relative GG: 0.688 vs. 0.633). GG was positively related to the triglyceride-glucose index. Kaplan-Meier curves revealed that groups of higher GG with DM had the worst outcomes. The outcomes differed among races and GG levels (all P < 0.05).

CONCLUSIONS

Among patients with CS, absolute and relative GGs were associated with increased 30-day all-cause mortality, regardless of DM. The relationship was stable after multivariate Cox regression analysis, PSM, and IPTW analysis. Furthermore, they reflect the severity of CS to some extent. Hyperlactatemia and insulin resistance may underlie the relationship between stress-induced hyperglycemia and poor outcomes in CS patients. They both improve the predictive efficacy of the GCS.

Optimal hemodynamic parameters for risk stratification in acute pulmonary embolism patients

Hemodynamic assessment of patients with pulmonary embolism (PE) remains a fundamental component of early risk stratification that in turn, influences subsequent monitoring and therapeutic strategies. The current body of literature and international evidence-based clinical practice guidelines focus mainly on the use of systolic blood pressure (SBP). The accuracy of this single hemodynamic parameter, however, and its optimal values for the identification of hemodynamic instability have been recently questioned by clinicians. For example, abnormal SBP or shock index may be a late indicator of adverse outcomes, signaling a patient in whom the cascade of hemodynamic compromise is already well underway. The aim of the present article is to review the current evidence supporting the use of SBP and analyze the potential integration of other parameters to assess the hemodynamic stability, impending clinical deterioration, and guide the reperfusion treatment in patients with PE, as well as to suggest potential strategies to further investigate this issue.

Blood glucose and lactate levels as early predictive markers in patients presenting with cardiogenic shock: A retrospective cohort study

Lactate and glucose are widely used biochemical parameters in current predictive risk scores for cardiogenic shock. Data regarding the relationship between lactate and glucose levels in cardiogenic shock are limited. Thus, we aimed to analyze glucose and lactate as early markers for in-hospital mortality in cardiogenic shock. In this retrospective cohort study, 312 patients presenting with cardiogenic shock to a tertiary-care hospital between 2016 and 2018 were included. Apparent cardiogenic shock was defined as hypoperfusion with hemodynamic compromise and biochemical marker increase due to diminished tissue perfusion, corresponding to SCAI shock stages. In-hospital mortality was assessed as the primary endpoint. The median age of the study population was 71 (60-79) years and the etiology of cardiogenic shock was acute myocardial infarction in 45.8%. Overall in-hospital mortality was 67.6%. In the receiver operating curve analysis, the area under the receiver-operating curve (AUC) for prediction of in-hospital mortality was higher for lactate (AUC: 0.757) than for glucose (AUC: 0.652). Both values were significantly associated with outcome (groups created with best cutoff values obtained from the Youden index). Correlation analysis showed a significant non-linear association of both values. In a multivariable stepwise Cox regression analysis, lactate remained an independent predictor for in-hospital mortality, whilst glucose, despite being implicated in energy metabolism, was not independently predictive for mortality. Together, these data suggest that lactate at admission is superior for mortality prediction in patients with apparent cardiogenic shock. Glucose was not independently predictive for mortality.

Mortality Prediction by Kinetic Parameters of Lactate and S-Adenosylhomocysteine in a Cohort of Critically Ill Patients

Tissue hypoxia is associated with the development of organ dysfunction and death in critically ill patients commonly captured using blood lactate. The kinetic parameters of serial lactate evaluations are superior at predicting mortality compared with single values. S-adenosylhomocysteine (SAH), which is also associated with hypoxia, was recently established as a useful predictor of septic organ dysfunction and death. We evaluated the performance of kinetic SAH parameters for mortality prediction compared with lactate parameters in a cohort of critically ill patients. For lactate and SAH, maxima and means as well as the normalized area scores were calculated for two periods: the first 24 h and the total study period of up to five days following ICU admission. Their performance in predicting in-hospital mortality were compared in 99 patients. All evaluated parameters of lactate and SAH were significantly higher in non-survivors compared with survivors. In univariate analysis, the predictive power for mortality of SAH was higher compared with lactate in all forms of application. Multivariable models containing SAH parameters demonstrated higher predictive values for mortality than models based on lactate parameters. The optimal models for mortality prediction incorporated both lactate and SAH parameters. Compared with lactate, SAH displayed stronger predictive power for mortality in static and dynamic application in critically ill patients.

Energy Metabolism: From Physiological Changes to Targets in Sepsis-induced Cardiomyopathy

Sepsis is a systemic inflammatory response syndrome caused by a variety of dysregulated responses to host infection with life-threatening multi-organ dysfunction. Among the injuries or dysfunctions involved in the course of sepsis, cardiac injury and dysfunction often occur and are associated with the pathogenesis of hemodynamic disturbances, also defined as sepsis-induced cardiomyopathy (SIC). The process of myocardial metabolism is tightly regulated and adapts to various cardiac output demands. The heart is a metabolically flexible organ capable of utilizing all classes of energy substrates, including carbohydrates, lipids, amino acids, and ketone bodies to produce ATP. The demand of cardiac cells for energy metabolism changes substantially in septic cardiomyopathy with distinct etiological causes and different times. This review describes changes in cardiomyocyte energy metabolism under normal physiological conditions and some features of myocardial energy metabolism in septic cardiomyopathy, and briefly outlines the role of the mitochondria as a center of energy metabolism in the septic myocardium, revealing that changes in energy metabolism can serve as a potential future therapy for infectious cardiomyopathy.

Lactate infusion elevates cardiac output through increased heart rate and decreased vascular resistance: a randomised, blinded, crossover trial in a healthy porcine model

BACKGROUND

Lactate is traditionally recognized as a by-product of anaerobic metabolism. However, lactate is a preferred oxidative substrate for stressed myocardium. Exogenous lactate infusion increases cardiac output (CO). The exact mechanism underlying this mechanism has yet to be elucidated. The aim of this study was to investigate the cardiovascular mechanisms underlying the acute haemodynamic effects of exogenous lactate infusion in an experimental model of human-sized pigs.

METHODS

In this randomised, blinded crossover study in eight 60-kg-pigs, the pigs received infusions with one molar sodium lactate and a control infusion of tonicity matched hypertonic saline in random order. We measured CO and pulmonary pressures using a pulmonary artery catheter. A pressure-volume admittance catheter in the left ventricle was used to measure contractility, afterload, preload and work-related parameters.

RESULTS

Lactate infusion increased circulating lactate levels by 9.9 mmol/L (95% confidence interval (CI) 9.1 to 11.0) and CO by 2.0 L/min (95% CI 1.2 to 2.7). Afterload decreased as arterial elastance fell by  -1.0 mmHg/ml (95% CI  -2.0 to  -0.1) and systemic vascular resistance decreased by  -548 dynes/s/cm5 (95% CI  -261 to  -835). Mixed venous saturation increased by 11 percentage points (95% CI 6 to 16), whereas ejection fraction increased by 16.0 percentage points (95% CI 1.1 to 32.0) and heart rate by 21 bpm (95% CI 8 to 33). No significant changes in contractility nor preload were observed.

CONCLUSION

Lactate infusion increased cardiac output by increasing heart rate and lowering afterload. No differences were observed in left ventricular contractility or preload. Lactate holds potential as a treatment in situations with lowered CO and should be investigated in future clinical studies.

Prognosis of patients with extreme acidosis on admission to the emergency department: A retrospective cohort study

AIM OF THE STUDY

The development of acidosis in critically ill patients is considered to be a negative prognostic factor, and when extreme, even incompatible with life. We aimed to test the prognosis of patients with a pH lower than 6.9 on emergency department admission.

METHODS

A retrospective cohort study in adult patients admitted to two emergency departments with a pH < 6.9 during the first 12 h of admission. Primary outcome was mortality within 24 h from emergency department admission. We performed a regression analysis of clinical and laboratory data in order to identify factors associated with mortality in this population.

RESULTS

We analyzed data of 206 admissions to the emergency departments between 2008 and 2018 with extreme acidosis. pH Values ranged from 6.898 to 6.35 (mean 6.8 and median 6.83). 60 (29%) of the patients survived the first 24 h. 35 patients (58%) of those also survived to hospital discharge, and of them 80% have returned to their previous functional status. Patient's age, type of acidosis, cardio-pulmonary resuscitation on arrival, and diagnosis on admission were correlated with survival.

CONCLUSIONS

A small but significant portion of patients with extreme acidosis on emergency department admission survive at least to 24 h and until hospital discharge. The clinical decision making should be based on other prognostic factors rather than pH value by itself.

Association between intraoperative hyperglycemia/hyperlactatemia and acute kidney injury following on-pump cardiac surgery: a retrospective cohort study

Background

Despite the long-lasting notion about the substantial contribution of intraoperative un-stabilization of homeostasis factors on the incidence on acute kidney injury (AKI), the possible influence of intraoperative glucose or lactate management, as a modifiable factor, on the development of AKI remains inconclusive.

Objectives

To investigated the relationship between intraoperative hyperglycemia, hyperlactatemia, and postoperative AKI in cardiac surgery.

Methods

A retrospective cohort study was conducted among 4,435 adult patients who underwent on-pump cardiac surgery from July 2019 to March 2022. Intraoperative hyperglycemia and hyperlactatemia were defined as blood glucose levels >10 mmol/L and lactate levels >2 mmol/L, respectively. The primary outcome was the incidence of AKI. All statistical analyses, including t tests, Wilcoxon rank sum tests, chi-square tests, Fisher's exact test, Kolmogorov-Smirnov test, logistic regression models, subgroup analyses, collinearity analysis, and receiver operating characteristic analysis, were performed using the statistical software program R version 4.1.1.

Results

Among the 4,435 patients in the final analysis, a total of 734 (16.55%) patients developed AKI after on-pump cardiac surgery. All studied intraoperative metabolic disorders was associated with increased AKI risk, with most pronounced odds ratio (OR) noted for both hyperglycemia and hyperlactatemia were present intraoperatively [adjusted OR 3.69, 95% confidence intervals (CI) 2.68-5.13, p < 0.001]. Even when hyperglycemia or hyperlactatemia was present alone, the risk of postoperative AKI remained elevated (adjusted OR 1.97, 95% CI 1.50-2.60, p < 0.001).

Conclusion

The presence of intraoperative hyperglycemia and hyperlactatemia may be associated with postoperative acute kidney injury (AKI) in patients undergoing on-pump cardiac surgery. Proper and timely interventions for these metabolic disorders are crucially important in mitigating the risk of AKI.

EARLY DECREASED RESPIRATORY CHAIN CAPACITY IN RESUSCITATED EXPERIMENTAL SEPSIS IS A MAJOR CONTRIBUTOR TO LACTATE PRODUCTION

ABSTRACT

Background : Increased plasma lactate levels in patients with sepsis may be due to insufficient oxygen delivery, but mitochondrial dysfunction or accelerated glycolysis may also contribute. We studied the effect of the latter on muscle metabolism by using microdialysis in a sepsis model with sustained oxygen delivery and decreased energy consumption or mitochondrial blockade. Methods : Pigs were subjected to continuous Escherichia coli infusion (sepsis group, n = 12) or saline infusion (sham group, n = 4) for 3 h. Protocolized interventions were applied to normalize the oxygen delivery and blood pressure. Microdialysis catheters were used to monitor muscle metabolism (naïve). The same catheters were used to block the electron transport chain with cyanide or the Na + /K + -ATPase inhibitor, ouabain locally. Results: All pigs in the sepsis group had positive blood cultures and a Sequential Organ Failure Assessment score increase by at least 2, fulfilling the sepsis criteria. Plasma lactate was higher in the sepsis group than in the sham group ( P < 0.001), whereas muscle glucose was lower in the sepsis group ( P < 0.01). There were no changes in muscle lactate levels over time but lactate to pyruvate ratio (LPR) was elevated in the sepsis versus the sham group ( P < 0.05). Muscle lactate, LPR, and glutamate levels were higher in the sepsis group than in the sham group in the cyanide catheters ( P < 0.001, all comparisons) and did not normalize in the former group. Conclusions: In this experimental study on resuscitated sepsis, we observed increased aerobic metabolism and preserved mitochondrial function. Sepsis and electron transport chain inhibition led to increased LPR, suggesting a decreased mitochondrial reserve capacity in early sepsis.

The Mechanisms of Action of Hyperbaric Oxygen in Restoring Host Homeostasis during Sepsis

The perception of sepsis has shifted over time; however, it remains a leading cause of death worldwide. Sepsis is now recognized as an imbalance in host cellular functions triggered by the invading pathogens, both related to immune cells, endothelial function, glucose and oxygen metabolism, tissue repair and restoration. Many of these key mechanisms in sepsis are also targets of hyperbaric oxygen (HBO2) treatment. HBO2 treatment has been shown to improve survival in clinical studies on patients with necrotizing soft tissue infections as well as experimental sepsis models. High tissue oxygen tension during HBO2 treatment may affect oxidative phosphorylation in mitochondria. Oxygen is converted to energy, and, as a natural byproduct, reactive oxygen species are produced. Reactive oxygen species can act as mediators, and both these and the HBO2-mediated increase in oxygen supply have the potential to influence the cellular processes involved in sepsis. The pathophysiology of sepsis can be explained comprehensively through resistance and tolerance to infection. We argue that HBO2 treatment may protect the host from collateral tissue damage during resistance by reducing neutrophil extracellular traps, inhibiting neutrophil adhesion to vascular endothelium, reducing proinflammatory cytokines, and halting the Warburg effect, while also assisting the host in tolerance to infection by reducing iron-mediated injury and upregulating anti-inflammatory measures. Finally, we show how inflammation and oxygen-sensing pathways are connected on the cellular level in a self-reinforcing and detrimental manner in inflammatory conditions, and with support from a substantial body of studies from the literature, we conclude by demonstrating that HBO2 treatment can intervene to maintain homeostasis.

DEVELOPMENT OF SCORE SYSTEM BASED ON POINT-OF-CARE ULTRASOUND TO PREDICT VASOPRESSOR REQUIREMENT FOR EMERGENCY PATIENTS WITH CARDIOPULMONARY SYMPTOMS

ABSTRACT

Objectives : Patients with cardiopulmonary symptoms admitted to the emergency department (ED) have high mortality and intensive care unit admission rates. We developed a new scoring system comprising concise triage information, point-of-care ultrasound, and lactate levels to predict vasopressor requirements. Methods : This retrospective observational study was conducted at a tertiary academic hospital. Patients with cardiopulmonary symptoms who visited the ED and underwent point-of-care ultrasound between January 2018 and December 2021 were enrolled. The influence of demographic and clinical findings on the requirement for vasopressor support within 24 h of ED admission was investigated. A new scoring system was developed using key components after stepwise multivariable logistic regression analysis. Prediction performance was evaluated using the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results : A total of 2,057 patients were analyzed. A stepwise multivariable logistic regression model showed high predictive performance in the validation cohort (AUC, 0.87). Eight key components were selected: hypotension, chief complaint, and fever at ED admission, and way of ED visit, systolic dysfunction, regional wall motion abnormalities, inferior vena cava status, and serum lactate level. The scoring system was developed based on the β coefficients of each component: accuracy, 0.8079; sensitivity, 0.8057; specificity, 0.8214; PPV, 0.9658; and NPV, 0.4035, with a cutoff value according to the Youden index. Conclusions : A new scoring system was developed to predict vasopressor requirements in adult ED patients with cardiopulmonary symptoms. This system can serve as a decision-support tool to guide efficient assignment of emergency medical resources.

Hemodynamic monitoring in cardiogenic shock

Cardiogenic shock (CS) is a life-threatening condition characterized by acute end-organ hypoperfusion due to inadequate cardiac output that can result in multiorgan failure, which may lead to death. The diminished cardiac output in CS leads to systemic hypoperfusion and maladaptive cycles of ischemia, inflammation, vasoconstriction, and volume overload. Obviously, the optimal management of CS needs to be readjusted in view of the predominant dysfunction, which may be guided by hemodynamic monitoring. Hemodynamic monitoring enables (1) characterization of the type of cardiac dysfunction and the degree of its severity, (2) very early detection of associated vasoplegia, (3) detection and monitoring of organ dysfunction and tissue oxygenation, and (4) guidance of the introduction and optimization of inotropes and vasopressors as well as the timing of mechanical support. It is now well documented that early recognition, classification, and precise phenotyping via early hemodynamic monitoring (e.g., echocardiography, invasive arterial pressure, and the evaluation of organ dysfunction and parameters derived from central venous catheterization) improve patient outcomes. In more severe disease, advanced hemodynamic monitoring with pulmonary artery catheterization and the use of transpulmonary thermodilution devices is useful to facilitate the right timing of the indication, weaning from mechanical cardiac support, and guidance on inotropic treatments, thus helping to reduce mortality. In this review, we detail the different parameters relevant to each monitoring approach and the way they can be used to support optimal management of these patients.

Serum Metabolomic Profiles in Critically Ill Patients with Shock on Admission to the Intensive Care Unit

Inflammatory processes are common in intensive care (ICU) patients and can induce multiple changes in metabolism, leading to increased risks of morbidity and mortality. Metabolomics enables these modifications to be studied and identifies a patient’s metabolic profile. The objective is to precise if the use of metabolomics at ICU admission can help in prognostication. This is a prospective ex-vivo study, realized in a university laboratory and a medico-surgical ICU. Metabolic profiles were analyzed by proton nuclear magnetic resonance. Using multivariable analysis, we compared metabolic profiles of volunteers and ICU patients divided into predefined subgroups: sepsis, septic shock, other shock and ICU controls. We also assessed possible correlations between metabolites and mortality. One hundred and eleven patients were included within 24 h of ICU admission, and 19 healthy volunteers. The ICU mortality rate was 15%. Metabolic profiles were different in ICU patients compared to healthy volunteers (p < 0.001). Among the ICU patients, only the subgroup of patients with septic shock had significant differences compared to the ICU control patients in several metabolites: pyruvate, lactate, carnitine, phenylalanine, urea, creatine, creatinine and myo-inositol. However, there was no correlation between these metabolite profiles and mortality. On the first day of ICU admission, we observed changes in some metabolic products in patients with septic shock, suggesting increased anaerobic glycolysis, proteolysis, lipolysis and gluconeogenesis. These changes were not correlated with prognosis.

Hyperlactatemia is a predictor of mortality in patients undergoing continuous renal replacement therapy for acute kidney injury

BACKGROUND

Hyperlactatemia occurs frequently in critically ill patients, and this pathologic condition leads to worse outcomes in several disease subsets. Herein, we addressed whether hyperlactatemia is associated with the risk of mortality in patients undergoing continuous renal replacement therapy (CRRT) due to acute kidney injury.

METHODS

A total of 1,661 patients who underwent CRRT for severe acute kidney injury were retrospectively reviewed between 2010 and 2020. The patients were categorized according to their serum lactate levels, such as high (≥ 7.6 mmol/l), moderate (2.1-7.5 mmol/l) and low (≤ 2 mmol/l), at the time of CRRT initiation. The hazard ratios (HRs) for the risk of in-hospital mortality were calculated with adjustment of multiple variables. The increase in the area under the receiver operating characteristic curve (AUROC) for the mortality risk was evaluated after adding serum lactate levels to the Sequential Organ Failure Assessment (SOFA) and the Acute Physiology and Chronic Health Evaluation (APACHE) II score-based models.

RESULTS

A total of 802 (48.3%) and 542 (32.6%) patients had moderate and high lactate levels, respectively. The moderate and high lactate groups had a higher risk of mortality than the low lactate group, with HRs of 1.64 (1.22-2.20) and 4.18 (2.99-5.85), respectively. The lactate-enhanced models had higher AUROCs than the models without lactates (0.764 vs. 0.702 for SOFA score; 0.737 vs. 0.678 for APACHE II score).

CONCLUSIONS

Hyperlactatemia is associated with mortality outcomes in patients undergoing CRRT for acute kidney injury. Serum lactate levels may need to be monitored in this patient subset.

Arterial lactate as a risk factor for death in respiratory failure related to coronavirus disease 2019: an observational study

BACKGROUND

Arterial lactate is a recognized biomarker associated with death in critically ill patients. The prognostic role of arterial lactate in acute respiratory failure due to the novel coronavirus disease 2019 (COVID-19) is unclear.

OBJECTIVES

We aimed to investigate the prognostic role of arterial lactate levels at admission in patients with COVID-19-related acute respiratory failure.

DESIGN AND METHODS

Cohorts of consecutive patients admitted to nonintensive care units (ICU) at study centers for COVID-19-related respiratory failure were merged into a collaborative database. The prognostic role of lactate levels at admission was assessed for continuous values and values ⩾2.0 mmol/l, and lactate clearance at 24 h through delta-lactate (ΔLac). The study outcome was 30-day in-hospital death. Cox proportional regression model was used to assess independent predictors of the study outcome.

RESULTS

At admission, 14.6% of patients had lactate levels ⩾2 mmol/l. In-hospital death at 30 days occurred in 57 out of 206 patients; 22.3% and 56.7% with normal or ⩾ 2 mmol/l lactate at admission, respectively. The median lactate level was 1.0 [interquartile range (IQR) 0.8-1.3] mmol/l and 1.3 (IQR 1.0-2.1) mmol/l in survivors and nonsurvivors, respectively (p-value < 0.001). After adjusting for age, relevant comorbidities, acidemia, and the severity of respiratory failure, lactate ⩾2.0 mmol/l was associated with in-hospital death (HR 2.53, 95% CI 1.29-4.95, p-value 0.0066), while Δ Lac ⩾0 was not (HR 1.37, 95% CI 0.42-4.49). These results were confirmed in patients with a pO2/FiO2-ratio (P/F ratio) ⩽300 mmHg.

CONCLUSIONS

In our study, increased arterial lactate at admission was independently associated with in-hospital death at 30 days in non-ICU patients with acute respiratory failure related to COVID-19.

Impact of Lactate on 30-Day All-Cause Mortality in Patients with and without Out-of-Hospital Cardiac Arrest Due to Cardiogenic Shock

In patients with cardiogenic shock (CS) due to myocardial infarction, elevated lactate levels are known to be negative predictors. Studies regarding the prognostic impact in patients with CS complicated by out-of-hospital cardiac arrest (OHCA) are limited. Two hundred and sixty-three consecutive patients with CS were included. The prognostic value of lactate on days 1, 2, 3, 4 and 8 was tested stratified by OHCA and non-OHCA. Statistical analyses included the univariable t-test, Spearman's correlation, C-statistics, Kaplan-Meier analyses, as well as multivariable mixed analysis of variance (ANOVA) and Cox proportional regression analyses. The primary endpoint of all-cause mortality occurred in 49.4% of the non-OHCA group and in 63.4% of the OHCA group. Multivariable regression models showed an association of lactate values with 30-day all-cause mortality in the non-OHCA (p = 0.024) and OHCA groups (p = 0.001). In Kaplan-Meier analyses, patients with lactate levels ≥ 4 mmol/L (log-rank p = 0.001) showed the highest risk for 30-day all-cause mortality in the non-OHCA as well as in the OHCA group. However, in C-statistics lactate on days 1 and 8 had a better discrimination for 30-day all-cause mortality in the OHCA group compared to the non-OHCA group. In conclusion, patients presenting with CS lactate levels showed a good prognostic performance, with and without OHCA. Especially, lactate levels on days 1 and 8 were more accurate in the discrimination for all-cause mortality in CS-patients with OHCA.

Premorbid beta blockade in sepsis is associated with a lower risk of a lactate concentration above the lactate threshold, a retrospective cohort study

Sepsis and septic shock represent a significant worldwide mortality burden. A lactate greater than 4 mmol/L is associated with increased mortality in septic patients. This is the concentration at the "lactate threshold" where serum lactate concentrations rise markedly with increased workload in exercise. Hyperlactatemia in both sepsis and exercise is contributed to by adrenergic agonism which stimulates aerobic glycolysis, increasing lactate production and decreasing lactate clearance. Our hypothesis is that in patients with sepsis, treatment with beta blockers in the community will be associated with a lower probability of initial lactate ≥ 4 mmol/L. This was single centre retrospective cohort study. We used an in-house SQL Database for all admissions to ICU/HDU for the 2017-2020 calendar years. The dataset was filtered for an APACHE III Diagnosis of sepsis. T-tests were used for continuous data, Chi squared and Fisher's exact test were used as appropriate to compare proportions. Logistic regression was used to investigate covariate effects. Of the 160 patient records analysed, 49 were prescribed beta blockers. A greater proportion of patients not prescribed beta blockers in the community had a first lactate ≥ 4 mmol/L (p = 0.049). This was robust to regression analysis. There was no difference in the proportion of patients with lactate ≥ 2 mmol/L (p = 0.52). In our cohort patients previously prescribed beta blockers were less likely to have a lactate of ≥ 4 mmol/mL. This supports the proposed mechanism that treatment with beta blockers increases the lactate threshold in sepsis. Further study is warranted.

Pharmacobezoar Formation From HPMC-AS-Containing Spray-Dried Formulations in Nonclinical Safety Studies in Rats

Changing the physical state from crystalline to amorphous is an elegant method to increase the bioavailability of poorly soluble new chemical entity (NCE) drug candidates. Subsequently, we report findings from repeat-dose toxicity studies of an NCE formulated as a spray-dried amorphous solid dispersion (SD-ASD) based on hydroxypropyl methylcellulose acetate succinate (HPMC-AS) in rats. At necropsy, agglomerates of SD-ASD were found in the stomach and small intestine, which in reference to literature were termed pharmacobezoars. We interpreted the pH-dependent insolubility of HPMC-AS in the acidic gastric environment to be a precondition for pharmacobezoar formation. Gastric pharmacobezoars were not associated with clinical signs or alterations of clinical pathology parameters. Pharmacobezoar-correlated histopathological findings were limited to the stomach and consisted of atrophy, erosion, ulcer, and inflammation, predominantly of the nonglandular mucosa. Pharmacobezoars in the small intestines induced obstructive ileus with overt clinical signs which required unscheduled euthanasia, prominent alterations of clinical pathology parameters indicative of hypotonic dehydration, degenerative and inflammatory processes in the gastrointestinal tract, and secondary renal findings. The incidence of pharmacobezoars increased with dose and duration of dosing. Besides the relevance of pharmacobezoars to animal welfare, they limit the non-observed adverse effect level in nonclinical testing programs and conclusively their informative value.

Estimating Enhanced Endogenous Glucose Production in Intensive Care Unit Patients with Severe Insulin Resistance

BACKGROUND

Critically ill ICU patients frequently experience acute insulin resistance and increased endogenous glucose production, manifesting as stress-induced hyperglycemia and hyperinsulinemia. STAR (Stochastic TARgeted) is a glycemic control protocol, which directly manages inter- and intra- patient variability using model-based insulin sensitivity (SI). The model behind STAR assumes a population constant for endogenous glucose production (EGP), which is not otherwise identifiable.

OBJECTIVE

This study analyses the effect of estimating EGP for ICU patients with very low SI (severe insulin resistance) and its impact on identified, model-based insulin sensitivity identification, modeling accuracy, and model-based glycemic clinical control.

METHODS

Using clinical data from 717 STAR patients in 3 independent cohorts (Hungary, New Zealand, and Malaysia), insulin sensitivity, time of insulin resistance, and EGP values are analyzed. A method is presented to estimate EGP in the presence of non-physiologically low SI. Performance is assessed via model accuracy.

RESULTS

Results show 22%-62% of patients experience 1+ episodes of severe insulin resistance, representing 0.87%-9.00% of hours. Episodes primarily occur in the first 24 h, matching clinical expectations. The Malaysian cohort is most affected. In this subset of hours, constant model-based EGP values can bias identified SI and increase blood glucose (BG) fitting error. Using the EGP estimation method presented in these constrained hours significantly reduced BG fitting errors.

CONCLUSIONS

Patients early in ICU stay may have significantly increased EGP. Increasing modeled EGP in model-based glycemic control can improve control accuracy in these hours. The results provide new insight into the frequency and level of significantly increased EGP in critical illness.

[Record-Breaking Acidosis]

Record-Breaking Acidosis Abstract. To maintain a stable cellular metabolism, tight regulation of blood pH within a normal range (pH 7,35-7,45) is essential. Even small aberrations can have detrimental effects, and pH values <6,8 or pH >7,8 are considered - based on current medical and physiological knowledge - incompatible with life [9-19].

Sepsis: a failing starvation response

Sepsis is involved in ~ 20% of annual global deaths. Despite decades of research, the current management of sepsis remains supportive rather than curative. Clinical trials in sepsis have mainly been focused on targeting the inflammatory pathway, but without success. Recent data indicate that metabolic dysregulation takes place in sepsis, and targeting metabolic pathways might hold much promise for the management of sepsis. Sepsis yields a strong starvation response, including the release of high-energy metabolites such as lactate and free fatty acids. However, the activity of two major transcription factors, GR and PPARα, is downregulated in hepatocytes, leading to the accumulation and toxicity of metabolites that, moreover, fail to be transformed into useful molecules such as glucose and ketones. We review the literature and suggest mechanisms and potential therapeutic targets that might prevent or revert the fatal metabolic dysregulation in sepsis.

Hyperlactataemia and acid-base disturbances in normotensive patients with acute heart failure

AIMS

Acute heart failure (AHF) may be associated with low-tissue perfusion and/or hypoxaemia leading to increased lactate levels and acid-base perturbations. Few data are available on the clinical significance of elevated lactate levels and primary acid-base disorders in the setting of AHF.

METHODS AND RESULTS

Arterial blood gas was obtained at admission in 4012 normotensive (systolic blood pressure ≥ 90 mmHg) patients with AHF. The association between lactate levels and acid-base status and in-hospital mortality was determined using multivariable logistic regression. Hyperlactataemia (>2 mmol/L) was present in 38.0% of patients and was strongly associated with markers of sympathetic activation, such as hyperglycaemia. Hyperlactataemia was present in 31.0%, 43.7%, and 42.0% of patients with normal pH, acidosis, and alkalosis, respectively. In-hospital mortality occurred in 16.4% and 11.1% of patients with and without hyperlactataemia [adjusted odds ratio (OR) 1.49; 95% confidence interval (CI) 1.22-1.82, P < 0.0001]. Compared with normal pH, the OR for in-hospital mortality was 2.48 (95% CI 1.95-3.16, P < 0.0001) in patients with acidosis and 1.77 (95% CI 1.32-2.26, P < 0.0001) in patients with alkalosis. The risk for in-hospital mortality was high with acidosis (18.1%) or alkalosis (10.4%) even with normal lactate. The most common primary acid-base disturbances included metabolic acidosis, respiratory acidosis, and metabolic alkalosis with respiratory acidosis having the highest risk for in-hospital mortality.

CONCLUSION

Hyperlactataemia was common in patients without hypotension and was associated with increased risk for in-hospital mortality. Hyperlactataemia is not associated with any specific acid-base disorder. Acute heart failure patients also present with diverse acid-base disorders portending increased in-hospital mortality.

Comparison of point-of-care NOVA CCX blood gas analyzer to laboratory analyzer in a population of healthy adult cats

OBJECTIVE

To compare the level of agreement of measurement of analytes (sodium, chloride, potassium, urea nitrogen [UN], creatinine, glucose) in a population of healthy adult cats between the point-of-care (POC) analyzer and laboratory analyzer. To establish reference intervals for the POC analyzer in healthy adult cats.

DESIGN

Prospective observational study.

SETTING

University teaching hospital.

ANIMALS

Fifty-five cats were screened. Seven cats were excluded due to aggression that prohibited phlebotomy, and 1 cat was excluded due to prolonged restraint; 47 cats were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In this patient population, reference intervals for the POC analyzer were calculated: sodium 145-157 mmol/L; chloride 116-124 mmol/L; potassium 3.4-5.5 mmol/L; UN 5.71-13.9 mmol/L (16-39 mg/dl); creatinine 74.3-189.2 mmol/L (0.84-2.14 mg/dl); and glucose 4-11.8 mmol/L (72-213 mg/dl). Comparison between the POC analyzer and laboratory analyzer using the Bland-Altman method was performed. The bias for each analyte is as follows: sodium 1.55 mmol/L; chloride 0.99 mmol/L; potassium 0.21 mmol/L; UN -0.25 mmol/L (-0.7 mg/dl); creatinine 9.73 mmol/L (0.11 mg/dl); and glucose 0.5 mmol/L (9.79 mg/dl).

CONCLUSIONS

Reference intervals for each analyte were similar to other chemistry analyzers. There was no significant difference between the POC and laboratory analyzers in analysis of UN, with a statistically significant difference observed with sodium, potassium, chloride, creatinine, and glucose. However, the values are likely not sufficiently different to alter initial clinical decisions regarding patient care.

Does severe hyperlactatemia during cardiopulmonary bypass predict a worse outcome?

INTRODUCTION

The aim of the current study was to evaluate the impact of increased blood lactate levels during cardiopulmonary bypass (CPB) on immediate results in patients who underwent open heart surgery.

MATERIALS AND METHODS

We performed a retrospective single-center study on 1290 patients. Adult cardiac surgical patients who underwent valve surgery, coronary artery bypass graft, combined procedure, adult congenital anomalies and aortic surgery were enrolled. Patients with associated comorbidities such as liver dysfunction, hemodynamic instability before surgery were excluded. Arterial blood lactate concentration was measured immediately after weaning from CPB and evaluated together with clinical data and outcomes including in hospital mortality. Patients were classified into 3 groups according to their peak arterial lactate level: group I [normal lactatemia, lactate ˂ 2 mmol/l (n = 749)], group II [mild hyperlactatemia, lactate 2-5 mmol/l (n = 489)], group III [severe hyperlactatemia, lactate ˃ 5 mmol/l (n = 52)].

RESULTS

When comparing outcomes across the 3 groups, severe hyperlactatemia was correlated with worse outcomes including higher in-hospital mortality, low output cardiac syndrome, postoperative renal insufficiency, myocardial infarction, red blood cell transfusion (RBC) transfusion, prolonged mechanical ventilation and longer intensive care unit (ICU) stay hours.

CONCLUSION

Blood lactate level above 5 mmol/l and more during CPB is associated with higher in-hospital mortality rate and postoperative complications. More attention must be given to correct the common abnormalities conditions inherent of CPB in order to conduct adequate tissue perfusion and reduce the risk of hyperlactatemia.

Exploring the Obesity Paradox in A Murine Model of Sepsis: Improved Survival Despite Increased Organ Injury in Obese Mice

ABSTRACT

Despite the known deleterious effects of obesity, clinical data indicate that overweight or obese patients experience higher rates of sepsis survival compared to normal and underweight patients; a phenomenon called the obesity paradox. Results from preclinical sepsis studies have not been able to replicate these findings. The objective of this study was to test the existence of the obesity paradox in a murine model of cecal slurry (CS)-induced sepsis with insulin-resistant diet-induced obese mice. Male C57BL/6 mice were provided high-fat (HFD) or low-fat (LFD) diets for 20 weeks. HFD-fed mice experienced higher rates of survival compared to LFD-fed mice after septic challenge induced by CS injection (66% vs. 25%, P = 0.01, survival assessed for 14 days). Despite the survival advantage, HFD-fed mice had higher rates of positive bacterial cultures and increased markers of kidney injury. Circulating levels of IL-6, IL-1β, TNFα, and IL-23 were equivalent 24 h after CS-injection; however, IL-17A was uniquely increased in HFD-fed mice. While LFD-fed mice maintained euglycemia, HFD-fed mice were hyperglycemic 6 and 12 h after CS-injection. Stable isotope resolved metabolomics analysis of liver tissue showed diverging pathways of glucose utilization during sepsis, with LFD-fed mice significantly upregulating glycolytic activity and HFD-fed mice decreasing glucose entry into the TCA cycle. This murine study corroborates clinical data that obesity confers a survival benefit in sepsis, albeit at the expense of more significant organ injury. The mechanisms promoting survival in the obese remain unknown; however, this model appears to be well-poised to begin answering this question. Differences in glucose utilization are a novel target to investigate this paradox.

Minimally invasive extracorporeal circulation in end-stage coronary artery disease patients undergoing myocardial revascularization

Background

Patients with coronary artery disease and concomitant heart failure (left ventricular ejection fraction < 35%) requiring myocardial revascularization are at risk of poor long-term prognosis and higher mortality. The benefits of minimally invasive extracorporeal circulation (MiECC), particularly in end-stage coronary artery disease patients undergoing myocardial revascularization, have not been completely described.

Materials and methods

In this single-centre control study, 60 end-stage coronary artery disease patients undergoing isolated coronary artery bypass grafting (CABG) were included. Patients were divided into two groups of 30 patients each undergoing CABG using MiECC or conventional extracorporeal circulation (cECC).

Results

In the MiECC group, oxygen delivery index (DO_2i) was 305 mL/min/m² in relation to indexed oxygen extraction ratio (O₂ER_i) 21.5%, whereas in the cECC group DO_2i was 288 mL/min/m² in relation to O₂ER_i 25.6% (p = 0.037). Lactate levels > 3 mmol/L were reported in 7 MiECC patients vs 20 cECC patients (p = 0.038), with blood glucose peak. Mean nadir hemoglobin values during cardiopulmonary bypass (CPB) were 9.7 g/dL in the MiECC group vs 7.8 g/dL in the cECC group (p = 0.044). Cardiac index during CPB was 2.4 L/min/m² in both groups. Red blood cell units administered were 8 vs 21 units in the MiECC vs cECC group (p = 0.022). A glycemic peak was recorded in 7 patients of the MiECC group and in 20 patients of the cECC group (p = 0.037).

Conclusion

In end-stage coronary artery disease, the MiECC technique was associated with a higher DO_2i compared to cECC. MiECC patients showed a significant reduction in red blood cell unit administration and peak intraoperative lactate levels, which correlated with better postoperative outcome.

UPLC-Q-TOF/MS-Based Plasma and Urine Metabolomics Contribute to the Diagnosis of Sepsis

In this study, we aimed to identify potential metabolic biomarkers that can improve the diagnostic accuracy of sepsis. Sixty-six patients including 30 septic and 36 nonsepsis patients from an intensive care unit were recruited. The global plasma and urine metabolomic profiles were determined by ultraperformance liquid chromatography coupled with a quadrupole time-of-flight mass spectrometry-based methodology. The risk factors, including both traditional physiological indicators and metabolic biomarkers, were investigated by binary logistic regression analysis and used to build a least absolute shrinkage and selection operator (Lasso) regression model to evaluate the ability of diagnosis. Fifty-five metabolites in plasma and 11 metabolites in urine were identified through orthogonal projections to latent structures discriminant analysis (OPLS-DA). Among them, ten (PE (20:4(5Z, 8Z, 11Z, 14Z)/P-18:0), harderoporphyrinogen, chloropanaxydiol, (Z)-2-octenal, N¹,N⁸-diacetylspermidine, 1-nitroheptane, venoterpine, α-CEHC, LysoPE (20:0/0:0), corticrocin) metabolites were identified as risk factors. The Lasso regression model incorporating these ten metabolic biomarkers and five traditional physiological indicators displayed better differentiation than the traditional model, represented by the elevated area under receiver operating characteristic curve (AUROC) from 96.80 to 100.0%. Furthermore, patients with septic shock presented a significantly lower level of PE-Cer (d16:1(4E)/19:0). This study suggests that metabolomic profiling could be an effective tool for sepsis diagnosis.

Clinical significance of lactate clearance in patients with cardiogenic shock: results from the RESCUE registry

Background

Limited data are available on the clinical significance of lactate clearance (LC) in patients with cardiogenic shock (CS). This study investigated the prognostic role of LC in CS patients.

Methods

We analyzed data from 628 patients in the RESCUE registry, a multicenter, observational cohort enrolled between January 2014 and December 2018. Univariable logistic regression analysis was performed to determine the prognostic implications of 24 h LC, and then patients were divided into two groups according to the cut-off value of 24 h LC (high lactate clearance [HLC] group vs. low lactate clearance [LLC] group). The primary outcome was in-hospital mortality. We also assessed all-cause mortality at 12 month follow-up and compared the prognostic performance of 24 h LC according to initial serum lactate level.

Results

In the univariable logistic regression analysis, 24 h LC was associated with in-hospital mortality (odds ratio 0.989, 95% confidence interval [CI] 0.985–0.993, p < 0.001), and the cut-off value for the LC of the study population was 64%. The HLC group (initial 24 h LC ≥ 64%, n = 333) had a significantly lower incidence of in-hospital death than the LLC group (n = 295) (25.5% in the HLC group vs. 42.7% in the LLC group, p < 0.001). During 12 months of follow-up, the cumulative incidence of all-cause death was significantly lower in the HLC group than in the LLC group (33.0% vs. 48.8%; hazard ratio 0.55; 95% CI 0.42–0.70; p < 0.001). In subgroup analysis, 24 h LC predicted in-hospital mortality better in patients with initial serum lactate > 5 mmol/L than in those with serum lactate ≤ 5 mmol/L (c-statistics of initial serum lactate > 5 mmol/L = 0.782 vs. c-statistics of initial serum lactate ≤ 5 mmol/L = 0.660, p = 0.011).

Conclusions

Higher LC during the early phase of CS was associated with reduced risk of in-hospital and 12 month all-cause mortalities. Patients with LC ≥ 64% during the 24 h after CS onset could expect a favorable prognosis, especially those with an initial serum lactate > 5 mmol/L.

Trial registration: RESCUE (REtrospective and prospective observational Study to investigate Clinical oUtcomes and Efficacy of left ventricular assist device for Korean patients with cardiogenic shock), NCT02985008, Registered December 5, 2016—retrospectively and prospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT02985008

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-021-00571-7.

Combination of Model for End-Stage Liver Disease and Lactate Predicts Death in Patients Treated With Salvage Transjugular Intrahepatic Portosystemic Shunt for Refractory Variceal Bleeding

BACKGROUND AND AIMS

Data about the prognosis of salvage transjugular intrahepatic portosystemic shunt (TIPS) using covered stents for refractory variceal bleeding caused by portal hypertension are scarce. We aimed to assess survival and to identify predictors of mortality in these patients.

APPROACH AND RESULTS

One hundred sixty-four patients with cirrhosis from five centers treated with salvage TIPS between 2007 and 2017 were retrospectively divided into a derivation cohort (83 patients) and a validation cohort (81 patients). Comparisons were performed using the Mann-Whitney and Fischer's exact test. Six-week overall survival (OS) was correlated with variables on the day of the TIPS using Kaplan-Meier curves with log-rank test and univariate/multivariate analyses using the Cox model. Eighty-three patients were included in the derivation cohort (male, 78%; age, 55 years, alcohol-associated cirrhosis, 88%; Model for End-Stage Liver Disease [MELD], 19 [15-27]; arterial lactate, 3.7 mmol/L [2.0-8.3]). Six-week OS rate was 58%. At multivariate analysis, the MELD score (OR, 1.064; 95% CI, 1.005-1.126; P = 0.028) and arterial lactate (OR, 1.063; 95% CI, 1.013-1.114; P = 0.032) were associated with 6-week OS. Six-week OS rates were 100% in patients with arterial lactate ≤2.5 mmol/L and MELD score ≤ 15 and 5% in patients with lactate ≥12 mmol/L and/or MELD score ≥ 30. The 81 patients of the validation cohort had similar MELD and arterial lactate level but lower creatinine level (94 vs 106 µmol/L, P = 0.008); 6-week OS was 67%. Six-week OS rates were 86% in patients with arterial lactate ≤2.5 mmol/L and MELD score ≤ 15 and 10% for patients with lactate ≥12 mmol/L and/or MELD score ≥ 30. In the overall cohort, rebleeding rate was 15.8% at 6 weeks, and the acute-on-chronic liver failure grade (OR, 1.699; 95% CI, 1.056-1.663; P = 0.040) was independently associated with rebleeding.

CONCLUSIONS

After salvage TIPS, 6-week mortality remains high and can be predicted by MELD score and lactate. Survival rate at 6 weeks was >85% in patients with arterial lactate ≤2.5 mmol/L and MELD score ≤ 15, while mortality was >90% for lactate ≥12 mmol/L and/or MELD score ≥ 30.

Lactate and Myocadiac Energy Metabolism

The myocardium is capable of utilizing different energy substrates, which is referred to as “metabolic flexibility.” This process assures ATP production from fatty acids, glucose, lactate, amino acids, and ketones, in the face of varying metabolic contexts. In the normal physiological state, the oxidation of fatty acids contributes to approximately 60% of energy required, and the oxidation of other substrates provides the rest. The accumulation of lactate in ischemic and hypoxic tissues has traditionally be considered as a by-product, and of little utility. However, recent evidence suggests that lactate may represent an important fuel for the myocardium during exercise or myocadiac stress. This new paradigm drives increasing interest in understanding its role in cardiac metabolism under both physiological and pathological conditions. In recent years, blood lactate has been regarded as a signal of stress in cardiac disease, linking to prognosis in patients with myocardial ischemia or heart failure. In this review, we discuss the importance of lactate as an energy source and its relevance to the progression and management of heart diseases.

Arterial Lactate in Cardiogenic Shock: Prognostic Value of Clearance Versus Single Values

OBJECTIVES

This study sought to compare single lactate values at admission (L1) and after 8 h (L2) with lactate clearance (LC) for mortality prediction in cardiogenic shock (CS).

BACKGROUND

Early estimation of prognosis in CS complicating acute myocardial infarction is crucial for tailored treatment selection. Arterial lactate is the most widely used point-of-care parameter in CS. In septic shock, lactate reduction over time-LC-has been extensively investigated. However, in CS, only limited data exist, and the prognostic value of LC is unknown.

METHODS

This study is a subanalysis of the IABP-SHOCK II (Intraaortic Balloon Pump in Cardiogenic Shock II) trial and the corresponding registry. Lactate levels were prospectively collected. All-cause mortality at 30 days was assessed as primary endpoint.

RESULTS

For 671 of 783 (85.7%) patients, L1 and L2 values were available. The area under the receiver-operating characteristic curve (L1: 0.69; L2: 0.76; LC: 0.59) showed no difference between L1 and LC (p = 0.20). In contrast, L2 was a significantly better predictive parameter than L1 or LC (p < 0.001 for both). In multivariable stepwise Cox regression analysis, L2 ≥3.1 mmol/l (best cutoff value by Youden index) and LC <-3.45%/h remained independently predictive for time to death (p < 0.001 for both), with L2 showing the highest chi-square test score (42.1) and hazard ratio (2.89; 95% confidence interval: 2.10 to 3.97).

CONCLUSIONS

Arterial lactate after 8 h is superior in mortality prediction in comparison with baseline lactate and LC. A cutoff value of 3.1 mmol/l for lactate after 8 h showed the best discrimination for assessing early prognosis in CS and may serve as new treatment goal. (Intraaortic Balloon Pump in Cardiogenic Shock II [IABP-SHOCK II]; NCT00491036).

Could Exogenous Insulin Ameliorate the Metabolic Dysfunction Induced by Glucocorticoids and COVID-19?

The finding that high-dose dexamethasone improves survival in those requiring critical care due to COVID-19 will mean much greater usage of glucocorticoids in the subsequent waves of coronavirus infection. Furthermore, the consistent finding of adverse outcomes from COVID-19 in individuals with obesity, hypertension and diabetes has focussed attention on the metabolic dysfunction that may arise with critical illness. The SARS coronavirus itself may promote relative insulin deficiency, ketogenesis and hyperglycaemia in susceptible individuals. In conjunction with prolonged critical care, these components will promote a catabolic state. Insulin infusion is the mainstay of therapy for treatment of hyperglycaemia in acute illness but what is the effect of insulin on the admixture of glucocorticoids and COVID-19? This article reviews the evidence for the effect of insulin on clinical outcomes and intermediary metabolism in critical illness.

Magnitude of gluconeogenesis and endogenous glucose production: are they predictable in clinical settings?

INTRODUCTION

Regulation of endogenous glucose production (EGP) is essential for glucose homeostasis. It includes gluconeogenesis (GNG) from non-carbohydrate substrates and hepatic glycogenolysis. Both these pathways are dysregulated in acute stress, but the magnitude of this deregulation cannot be assessed in clinical practice. The study aims at identifying clinically available variables predictive of EGP and GNG magnitude by modeling routinely available data.

METHODS

This exploratory study is based on the data from the Supplemental Parenteral Nutrition study 2 (SPN2), which measured EGP and GNG at days 4 and 10 in 23 critically ill patients. The correlation between EGP and GNG and 83 potential clinical indicators were explored, using single-stage and multivariate analysis.

RESULTS

On single-stage analysis, the strongest correlations were noradrenaline dose at day 4 with GNG (R = 0.71; P = 0.0004) and Nutrition risk screening score (NRS) with EGP (R = 0.42; P = 0.05). At day 10, VO₂ (R = 0.59, P = 0.04) was correlated with GNG and VCO₂ with EGP (R = 0.85, P = 0.00003). Cumulated insulin dose between days 5 and 9 was correlated to EGP at day 10 (R = 0.55, P = 0.03). Our multivariate model could predict EGP at day 4 (VCO₂, glucose and energy intake) with an error coefficient (e.c.) between 7.8% and 23.4% (minimal and maximal error), and GNG at day 10 (age, mean and basal blood glucose), with an e.c. of 18.5% and 29.9%. GNG at day 4 and EGP at day 10 could not be predicted with an e.c. < 40%.

CONCLUSION

This preliminary exploratory study shows that GNG and EGP have different predictors on days 4 and 10; EGP is more correlated with the metabolic level, while GNG is dependent on external factors. Nevertheless, a bundle of variables could be identified to empirically assess the magnitude of both values. Our results suggest that a robust model might be built, but requires a prospective study including a larger number of patients.

Influence of endocrine disease on l-lactate concentrations in blood of ponies

Background

Blood l‐lactate concentrations are higher in people with developing or established diabetes mellitus and insulin resistance.

Objectives

To investigate whether blood l‐lactate concentrations are positively correlated with measures of insulin dysregulation (ID) or increased autumnal ACTH concentrations in ponies.

Animals

Systemically healthy client‐owned ponies (n = 101).

Methods

Prospective case‐control study. Blood samples were obtained from 101 clinically healthy ponies. Breed, weight, height, and subjective and objective measures of body condition were recorded. Blood l‐lactate, glucose, triglyceride, total adiponectin, and ACTH concentrations were measured and an oral sugar test (OST) was carried out. Correlations between blood l‐lactate and variables of endocrine health were determined.

Results

Using a seasonal cutoff point of ACTH concentrations ≥47 pg/mL, 55 ponies had increased autumnal ACTH concentrations and 45 did not. Using a basal insulin concentration of >50 μiU/mL, 42 ponies were diagnosed with ID and 58 were not. Using a 60 minutes after OST cutoff point of >45 μiU/mL, 57 ponies had ID and 37 did not. Blood l‐lactate concentrations were significantly lower in obese (average body condition score ≥ 7/9) compared to nonobese ponies (0.6 mmol/L; range, 0.0‐1.9 mmol/L vs 0.8 mmol/L; range, 0.3‐2.7 mmol/L; P = .01). No other significant correlations were detected. No differences were detected between ponies with and without increased autumnal ACTH concentrations (0.7 mmol/L; range, 0.0‐2.7 mmol/L vs 0.7 mmol/L; range, 0.3‐1.8 mmol/L; P = .84) and with and without ID (0.7 mmol/L; range, 0.3‐2.7 mmol/L vs 0.8 mmol/L; range, 0.0‐1.6 mmol/L; P = .63).

Conclusions and Clinical Importance

Results do not support an effect of endocrine status on l‐lactate concentrations in blood of ponies.

The effect of midodrine on lactate clearance in patients with septic shock: a pilot study

Background: The effect of midodrine on lactate clearance has not been assessed in critically ill patients yet. Objective: The goal of this study was to assess the effect of adjunctive midodrine therapy on lactate clearance in patients with septic shock. Materials & methods: Patients with septic shock were assigned to receive either adjunctive midodrine 10 mg three-times a day for 5 days (midodrine group = 15 patients) or not (control group = 13 patients). Results: The lactate clearance was significantly faster in the midodrine group than the control group (p = 0.049) with a large effect size (ηp2 = 0.141). Conclusion: When midodrine was added to intravenous vasopressors, it significantly accelerated lactate clearance in patients with septic shock. Trial registration number: IRCT20100228003449N25 (Clinicaltrials.gov).

Correlation between L-Lactate Concentrations in Beef Cattle, Obtained Using a Hand-Held Lactate Analyzer and a Lactate Assay Colorimetric Kit

Simple Summary

Lactate is a metabolite used in animal research as an indicator of muscle fatigue; therefore, it has been used as an indicator of cattle response to long distance transportation. The aim of this study was to assess the relationship of L-lactate concentrations measured using a Lactate Scout+ hand-held analyzer and a traditional lactate assay colorimetric kit. Blood samples were collected from 96 steers prior to loading and after 36 h of transportation, and prior to reloading and after an additional 4 h of road transportation, and on d 1, 2, 3, 5, 14, and 28 after transport. The Lactate Scout+ hand-held analyzer strip was dipped in blood at the time of sampling, while blood samples were collected into sodium fluoride tubes for use in the colorimetric analysis. Correlations were calculated to assess the strength of the relationship between the L-lactate concentrations measured between methods. The strength of the correlation and the level of statistical significance varied over the observed time points, while the correlation for the pooled data was weak. Based on the low strength of the correlation, the Lactate Scout+ analyzer is not a suitable alternative to a colorimetric assay for measuring L-lactate in transported cattle.

Abstract

Lactate is a product of anaerobic glycolysis, used in animal research as an indicator of muscle fatigue. Therefore, it has been used as an indicator of cattle response to long distance transportation. The aim of this study was to assess the relationship of L-lactate concentrations measured using a Lactate Scout+ analyzer and a traditional lactate assay colorimetric kit. Blood samples were collected by venipuncture from 96 steers (Black or Red Angus × Hereford/Simmental and Black or Red Angus × Charolais; 247 ± 38.2 kg BW) prior to loading (LO1) and after 36 h of transport, and prior to reloading and after an additional 4 h of road transportation, and on d 1, 2, 3, 5, 14, and 28 after transport. The Lactate Scout+ analyzer strip was dipped in blood at the time of sampling, while blood samples were collected into sodium fluoride tubes for use in the colorimetric analysis. Pearson correlations were calculated to assess the strength of the relationship between the experimental methods for the quantification of L-lactate concentrations. The magnitude and direction of the correlation, and the level of statistical significance varied over the observed time points, ranging from r = −0.03 (p = 0.75; LO1) to r = 0.75 (p < 0.0001; d 3). The correlation for the pooled data was weak but statistically significant (r = 0.33, p < 0.0001). Based on the low magnitude of the correlation due to variability across sampling time points in this study, the Lactate Scout+ analyzer is not a suitable alternative to a lab-based assay (considered the gold standard) for measuring L-lactate in transported cattle.

Stepwise lactate kinetics in critically ill patients: prognostic, influencing factors, and clinical phenotype

Background

To investigate the optimal target e of lactate kinetics at different time during the resuscitation, the factors that influence whether the kinetics achieve the goals, and the clinical implications of different clinical phenotypes.

Methods

Patients with hyperlactatemia between May 1, 2013 and December 31, 2018 were retrospectively analyzed. Demographic data, basic organ function, hemodynamic parameters at ICU admission (T0) and at 6 h, 12 h, 24 h, 48 h, and 72 h, arterial blood lactate and blood glucose levels, cumulative clinical treatment conditions at different time points and final patient outcomes were collected.

Results

A total of 3298 patients were enrolled, and the mortality rate was 12.2%. The cutoff values of lactate kinetics for prognosis at 6 h, 12 h, 24 h, 48 h, and 72 h were 21%, 40%, 57%, 66%, and 72%. The APACHE II score, SOFA score, heart rate (HR), and blood glucose were risk factors that correlated with whether the lactate kinetics attained the target goal. Based on the pattens of the lactate kinetics, eight clinical phenotypes were proposed. The odds ratios of death for clinical phenotypes VIII, IV, and II were 4.39, 4.2, and 5.27-fold of those of clinical phenotype I, respectively.

Conclusion

Stepwise recovery of lactate kinetics is an important resuscitation target for patients with hyperlactatemia. The APACHE II score, SOFA score, HR, and blood glucose were independent risk factors that influenced achievement of lactate kinetic targets. The cinical phenotypes of stepwise lactate kinetics are closely related to the prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-021-01293-x.

The anabolic role of the Warburg, Cori-cycle and Crabtree effects in health and disease

In evolution, genes survived that could code for metabolic pathways, promoting long term survival during famines or fasting when suffering from trauma, disease or during physiological growth. This requires utilization of substrates, already present in some form in the body. Carbohydrate stores are limited and to survive long, their utilization is restricted to survival pathways, by inhibiting glucose oxidation and glycogen synthesis. This leads to insulin resistance and spares muscle protein, because being the main supplier of carbon for new glucose production. In these survival pathways, part of the glucose is degraded in glycolysis in peripheral (muscle) tissues to pyruvate and lactate (Warburg effect), which are partly reutilized for glucose formation in liver and kidney, completing the Cori-cycle. Another part of the glucose taken up by muscle contributes, together with muscle derived amino acids, to the production of substrates consisting of a complete amino acid mix but extra non-essential amino acids like glutamine, alanine, glycine and proline. These support cell proliferation, matrix deposition and redox regulation in tissues, specifically active in host response and during growth. In these tissues, also glucose is taken up delivering glycolytic intermediates, that branch off and act as building blocks and produce reducing equivalents. Lactate is also produced and released in the circulation, adding to the lactate released by muscle in the Cori-cycle and completing secondary glucose cycles. Increased fluxes through these cycles lead to modest hyperglycemia and hyperlactatemia in states of healthy growth and disease and are often misinterpreted as induced by hypoxia.

Evaluating the Possibility of Translating Technological Advances in Non-Invasive Continuous Lactate Monitoring into Critical Care

Lactate is widely measured in critically ill patients as a robust indicator of patient deterioration and response to treatment. Plasma concentrations represent a balance between lactate production and clearance. Analysis has typically been performed with the aim of detecting tissue hypoxia. However, there is a diverse range of processes unrelated to increased anaerobic metabolism that result in the accumulation of lactate, complicating clinical interpretation. Further, lactate levels can change rapidly over short spaces of time, and even subtle changes can reflect a profound change in the patient's condition. Hence, there is a significant need for frequent lactate monitoring in critical care. Lactate monitoring is commonplace in sports performance monitoring, given the elevation of lactate during anaerobic exercise. The desire to continuously monitor lactate in athletes has led to the development of various technological approaches for non-invasive, continuous lactate measurements. This review aims firstly to reflect on the potential benefits of non-invasive continuous monitoring technology within the critical care setting. Secondly, we review the current devices used to measure lactate non-invasively outside of this setting and consider the challenges that must be overcome to allow for the translation of this technology into intensive care medicine. This review will be of interest to those developing continuous monitoring sensors, opening up a new field of research.

Etiology of lactic acidosis in malaria

Lactic acidosis and hyperlactatemia are common metabolic disturbances in patients with severe malaria. Lactic acidosis causes physiological adverse effects, which can aggravate the outcome of malaria. Despite its clear association with mortality in malaria patients, the etiology of lactic acidosis is not completely understood. In this review, the possible contributors to lactic acidosis and hyperlactatemia in patients with malaria are discussed. Both increased lactate production and impaired lactate clearance may play a role in the pathogenesis of lactic acidosis. The increased lactate production is caused by several factors, including the metabolism of intraerythrocytic Plasmodium parasites, aerobic glycolysis by activated immune cells, and an increase in anaerobic glycolysis in hypoxic cells and tissues as a consequence of parasite sequestration and anemia. Impaired hepatic and renal lactate clearance, caused by underlying liver and kidney disease, might further aggravate hyperlactatemia. Multiple factors thus participate in the etiology of lactic acidosis in malaria, and further investigations are required to fully understand their relative contributions and the consequences of this major metabolic disturbance.

Quantitative Assessment of Blood Lactate in Shock: Measure of Hypoxia or Beneficial Energy Source

Blood lactate concentration predicts mortality in critically ill patients and is clinically used in the diagnosis, grading of severity, and monitoring response to therapy of septic shock. This paper summarizes available quantitative data to provide the first comprehensive description and critique of the accepted concepts of the physiology of lactate in health and shock, with particular emphasis on the controversy of whether lactate release is simply a manifestation of tissue hypoxia versus a purposeful transfer ("shuttle") of lactate between tissues. Basic issues discussed include (1) effect of nonproductive lactate-pyruvate exchange that artifactually enhances flux measurements obtained with labeled lactate, (2) heterogeneous tissue oxygen partial pressure (Krogh model) and potential for unrecognized hypoxia that exists in all tissues, and (3) pathophysiology that distinguishes septic from other forms of shock. Our analysis suggests that due to exchange artifacts, the turnover rate of lactate and the lactate clearance are only about 60% of the values of 1.05 mmol/min/70 kg and 1.5 L/min/70 kg, respectively, determined from the standard tracer kinetics. Lactate turnover reflects lactate release primarily from muscle, gut, adipose, and erythrocytes and uptake by the liver and kidney, primarily for the purpose of energy production (TCA cycle) while the remainder is used for gluconeogenesis (Cori cycle). The well-studied physiology of exercise-induced hyperlactatemia demonstrates massive release from the contracting muscle accompanied by an increased lactate clearance that may occur in recovering nonexercising muscle as well as the liver. The very limited data on lactate kinetics in shock patients suggests that hyperlactatemia reflects both decreased clearance and increased production, possibly primarily in the gut. Our analysis of available data in health and shock suggests that the conventional concept of tissue hypoxia can account for most blood lactate findings and there is no need to implicate a purposeful production of lactate for export to other organs.

The effect of hyperlactatemia timing on the outcomes after cardiac surgery

Background

Several studies linked postoperative hyperlactatemia to worse outcomes in adult patients undergoing cardiac surgery. However, data on the effect of timing of hyperlactatemia on outcomes are scarce. We sought to determine the prevalence of early hyperlactatemia (EHL) and its impact on clinical outcomes compared to late hyperlactatemia (LHL) in patients undergoing ACS procedures.

Results

We included 305 consecutive adult patients who underwent cardiac surgery procedures between July 2017 and Nov 2019 at a single institution. Lactate level was measured in the first 10 h after surgery and EHL was defined as lactate level > 3 mmol/L in the first hour after surgery. Logistic regression analysis was performed to determine predictors of EHL. Seventeen percent (n = 52) had EH while 83% (n = 253) did not. Patients with EHL had significantly longer cardiopulmonary bypass (P = 0.001) and cross-clamp (P = 0.001) times due to increased surgical complexity in this group. Early hyperlactatemia was associated with increased post-operative extracorporeal membrane oxygenation (ECMO) support (0% vs 5.7%, P < 0.001), longer intensive care unit stay (P = 0.004), and increased hospital mortality (0% vs. 3.8%, P = 0.009). Cardiopulmonary bypass time (OR 1.001; 95% CI 1.011–1.012, P = 0.02) and glucose level (OR 1.2; 95% CI 1.1–1.3, P = 0.003) were independently associated with increased rate of EHL. In contrast, diabetes mellitus (OR 0.26; 95% CI 0.12–0.55, P < 0.001) significantly attenuated the rate of EHL.

Conclusions

Early hyperlactatemia after cardiac surgery was associated with increased morbidity and mortality. Late hyperlactatemia was very common and had a self-limiting and benign course.

Identification of cardiovascular and molecular prognostic factors for the medium-term and long-term outcomes of sepsis (ICROS): protocol for a prospective monocentric cohort study

INTRODUCTION

Sepsis is one of the most prevalent life-threatening conditions in the intensive care unit. Patients suffer from impaired organ function, reduced physical functional capacity and decreased quality of life even after surviving sepsis. The identification of prognostic factors for the medium-term and long-term outcomes of this condition is necessary to develop personalised theragnostic approaches. Sepsis can cause cardiac impairment. The impact of this septic cardiomyopathy on patient's long-term outcome remains unclear. This study aims to evaluate cardiovascular risk factors, particularly the occurrence of septic cardiomyopathy, regarding their suitability as prognostic factors for the short-term and long-term outcomes of septic patients. Additionally, the study seeks to validate preclinical pathophysiological findings of septic cardiomyopathy in the clinical setting.

METHODS AND ANALYSIS

In this prospective monocentric cohort study, patients will be clinically assessed during the acute and postacute phase of sepsis and two follow-ups after 6 and 12 months. To determine the effect of septic cardiomyopathy and concomitant cellular and molecular changes on patient mortality and morbidity, a comprehensive cardiovascular and molecular deep phenotyping of patients will be performed. This includes an echocardiographic and electrocardiographic assessment, and the evaluation of heart rate variability, body composition, mitochondrial oxygen metabolism, macrocirculation and microcirculation, and endothelial barrier function. These analyses are complemented by routine immunological, haematological and biochemical laboratory tests and analyses of the serum metabolome and lipidome, microbiome and epigenetic modifications of immune cells. The reversibility of patients' organ dysfunction, their quality of life and physical functional capacity will be investigated in the follow-ups. Patients with cardiomyopathy without infection and healthy subjects will serve as control groups.

ETHICS AND DISSEMINATION

Approval was obtained from the Ethics Committee of the Friedrich Schiller University Jena (5276-09/17). The results will be published in peer-reviewed journals and presented at appropriate conferences.

TRIAL REGISTRATION NUMBERS

DRKS00013347; NCT03620409.

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.

Early lactate area scores and serial blood lactate levels as prognostic markers for patients with septic shock: a systematic review

Septic shock is the main cause of morbidity and mortality in patients and second leading cause of mortality among subjects in noncoronary intensive care units. Based on the literature, elevated serum lactate levels are associated with poor outcomes in patients with septic shock, which may occur due to various reasons, such as tissue hypoxia and anaerobic metabolism. This systematic review was conducted to collect data on the lactate area and area under the curve (AUC) of serial lactate levels for the determination of the predictive values of these factors to diagnose septic shock. For this purpose, the articles published up to 2019 were searched in four databases, including Google Scholar, PubMed, Scopus, and Medline. This study was carried out based on the seven stages recommended in the Cochrane Handbook. All articles were searched using several keywords, including 'Lactate Area Score' and 'Serial Lactate Levels' in combination with 'Septic Shock'. There were a total of 14 studies mainly focused on the assessment of the lactate area and serial lactate levels in patients with septic shock. The inclusion criteria were a clear explanation of the predictive role of repeated lactate measurements in patients with septic shock, sample size larger than 50, examination on human samples, and publication in English. All case-control, prospective, and retrospective studies on human subjects assessing the predictive value of repeated lactate measurements in the diagnosis of patients with septic shock at high risk of mortality were entered in the present review. The lactate area is a new concept introduced as the sum of the AUC of serial lactate levels. This factor can determine the severity and duration of hyperlactatemia. Based on the obtained results, there was an association between the lactate area score and 28-day mortality of patients with septic shock; therefore, early lactate area score can be considered a prognostic marker for the prediction of mortality rate in these patients. There are few studies on the evaluation of the lactate area score and no more information about the prognostic ability of the lactate area score. This was the main limitation of the present study. Moreover, the lactate area is introduced as the sum of the AUC of serial lactate levels and cannot reflect the trend of serial lactate. The trend may be supported by lactate clearance but not lactate area.

Associations between oxygen delivery and cardiac index with hyperlactatemia during cardiopulmonary bypass

Objective

Metabolism management plays an essential role during cardiopulmonary bypass (CPB). There are different metabolic management devices integrated to heart-lung machines; the most commonly used and accepted metabolic target is indexed oxygen delivery (DO_2i) (280 mL/min/m²) and cardiac index (CI) (2.4 L/min/m²), which can be managed independently or according to other metabolic parameters. Our objective was to compare lactate production during CPB procedures using different metabolic management: DO_2i in relation to indexed oxygen extraction ratio (O₂ER_i) and CI in relation to mixed venous oxygen saturation (SvO₂).

Methods

Data on 500 CPB procedures were retrospectively collected in a specialized regional tertiary cardiac surgery center in Italy between September and 2012 and November 2019. In group A, the DO_2i with 280 mL/min/m² target in relation to O₂ER_i 25% was used; in group B, CI with 2.4 L/min/m² target in relation to SvO₂ 75% was used. During CPB, serial arterial blood gas analyses with blood lactate and glucose determinations were obtained. Hyperlactatemia (HL) was defined as a peak arterial blood lactate concentration >3 mmol/L. The postoperative outcome of patients with or without HL was compared.

Results

Eight pre- and intraoperative factors were found to be significantly associated with peak blood lactate level during CPB at univariate analysis. HL (>3 mmol/L) was detected in 15 (6%) patients of group A and in 42 (16.8%) patients of group B (P = .022); hyperglycemia (>160 mg/dL) was found in 23 (9.2%) patients of group A and in 53 (21.2%) patients of group B (P = .038). Patients with HL during CPB had a significant increase in serum creatinine value, higher rate of prolonged mechanical ventilation time and intensive care unit stay. A cutoff of DO_2i <270 mL/min/m² in relation to O₂ER_i >35% in group A and a cutoff of CI <2.4 L/min/m² in relation to SvO₂ <65% in group B were found to have a positive predictive value of 80% and 75% for HL, respectively. A cutoff of DO_2i >290 mL/min/m² in relation to O₂ER_i 24% in group A and a cutoff of CI >2.4 L/min/m² in relation to SvO₂ >75% in group B were found to have a negative predictive value of 78% and 62% for HL, respectively.

Conclusions

This retrospective observational analysis showed that management of DO_2i in relation to O₂ER_i was 16% more specific in terms of negative predictive value for HL during CPB compared with the use of CI in relation to SvO₂. Group A reported a significant reduction in the incidence of intraoperative lactate peak, correlated with postoperative reduction of serum creatinine value, mechanical ventilation time, and intensive care unit stay, compared with group B.