Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery: Guidelines of the German Society of Anaesthesiology and Intensive Care Medicine in collaboration with the German Association of the Scientific Medical Societies

Haemodynamic monitoring and management are cornerstones of perioperative care. The goal of haemodynamic management is to maintain organ function by ensuring adequate perfusion pressure, blood flow, and oxygen delivery. We here present guidelines on "Intraoperative haemodynamic monitoring and management of adults having non-cardiac surgery" that were prepared by 18 experts on behalf of the German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und lntensivmedizin; DGAI).

The prognostic utility of Lactate/Albumin*Age score in septic patient with normal lactate level

Background

A previous study has shown that the lactate/albumin*age (LAA) score is useful for predicting mortality in patients with sepsis admitted to the ICU. We aimed to evaluate the clinical significance of the LAA score in patients with sepsis who presented to the emergency department (ED).

Methods

This retrospective observational study used data from the Korean Shock Society Registry collected between January 2017 and December 2021. The prognostic performance of the LAA score for predicting the 28-day mortality was evaluated. Lactate and albumin levels were measured immediately after arrival to the ED.

Results

Of the 5346 patients with sepsis, data from 3240 were analyzed. The area under the receiver operating characteristic curve (AUROC) of the LAA score (0.737, 95 % confidence interval (CI) 0.716-0.757), was higher than that of lactate (0.699, 95 % CI 0.677-0.720, p < 0.001), lactate/albumin (LA) ratio (0.730, 95 % CI 0.709-0.751, p = 0.016), and Sequential Organ Failure Assessment (SOFA) score (0.698, 95 % confidence interval 0.676-0.720, p = 0. 004), and Acute Physiology and Chronic Health Evaluation (APACHE) II scores (0.672; 95 % confidence interval 0.649-0.694, p < 0.001). The optimal cut-off value for the LAA score was 119.9. In the Kaplan-Meier analysis according to the optimal cutoff value, the 28-day mortality rates were higher in the high LAA score group (log-rank test, p < 0.001). The LAA score was independently associated with 28-day mortality in the multivariate Cox proportional hazards model (adjusted hazard ratio 2.07, 95 % CI 1.76-2.43, p < 0.001). In the normal (<2 mmol/L) lactate group, the AUROC value for LAA score was higher than LA ratio (normal group 0.674 vs 0.634, p < 0.004). In patients over 65 years old, LAA score (0.731) showed a higher AUROC value than LA ratio (0.725). (p < 0.001).

Conclusion

The LAA score may be used as an independent predictor of mortality in patients with sepsis in the emergency department. Our results show that it performs better than serum lactate alone, LA ratio, and SOFA and APACHE II scores. While this suggests that the LAA could provide clinicians with a useful tool for timely early intervention and care planning in patients with a poor prognosis, further validation in large multicenter prospective studies are necessary to confirm its reliability and practicality as a readily available and objective biomarker.

β-Adrenergic Agonist-Induced Lactic Acidosis: A Case Report

β-Adrenergic agonist medications such as albuterol are the mainstay for treatment of patients with acute asthma exacerbations. Patients who present to the emergency department with severe symptoms are often treated with multiple albuterol doses in sequence to maximize the impact of the medications, relax bronchoconstriction, and relieve their breathlessness. Patients who present with acute dyspnea have numerous potential causes of hyperlactatemia and acidosis including an uncommonly recognized outcome of albuterol administration. This clinical case report outlines a scenario where a patient who was treated for an acute asthma exacerbation had rising lactate levels despite improving clinically. Causes of elevated lactate levels are discussed, particularly related to β-adrenergic agonist use, and considerations for monitoring and withdrawal of albuterol administration are outlined.

The Correlation Between the Lactate/Albumin Ratio and Sequential Organ Failure Assessment (SOFA) Score in Patients With Sepsis and Septic Shock

Background Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection, often resulting in severe outcomes such as septic shock and death. Globally, sepsis ranks among the most common causes of illness and death. The Sequential Organ Failure Assessment (SOFA) score is an established marker used to assess and predict the extent of organ failure in septic patients. The introduction of novel markers, such as the lactate/albumin (L/A) ratio, serves as a prognostic indicator in critical care settings, particularly for patients with sepsis. In this context, a higher L/A ratio upon admission aids in assessing disease severity and improving clinical decision-making to reduce mortality and adverse outcomes, which we aim to correlate through our study. Materials and methods This was an observational cross-sectional analysis conducted on 100 patients aged over 18 years who met the "Sepsis-3" guidelines and were admitted to the medical intensive care unit of Dr. D. Y. Patil Hospital, Pune, Maharashtra, India, between October 2022 and May 2024. Patients with chronic liver disease classified as Child-Pugh class C were excluded, as were those with chronic kidney disease (CKD). Written informed consent was obtained from each participant before the study. Data were collected through physical examination, routine laboratory investigations, and radiological assessments. Statistical analysis was performed using IBM SPSS version 20 (IBM Corp., Armonk, NY). Descriptive statistical analyses were conducted using the SPSS data editor. Statistical significance was considered at a p-value of less than 0.05 for all analyses. Results In the study population, 78 patients survived, while 22 patients died. The L/A ratio and SOFA score were significantly higher in non-survivors compared to survivors, both upon admission and thereafter, with statistical significance (p < 0.05). The correlation between the L/A ratio and the SOFA score was examined upon admission at 24 hours, 48 hours, day 7, and day 28. Pearson correlation analysis revealed statistically significant results (p < 0.05) throughout the entire study period. Conclusion A high L/A ratio, along with the SOFA score at ICU admission, was associated with a grave prognosis and poor outcomes, serving as independent risk factors for ICU admission. Therefore, patients with a high L/A ratio and SOFA score should be identified early and managed aggressively to avoid poor outcomes. Our study demonstrates that combining serum lactate and serum albumin levels into the L/A ratio significantly enhances prognostic accuracy compared to using serum lactate alone.

Metabolic complications of psychotropic medications in psychiatric disorders: Emerging role of de novo lipogenesis and therapeutic consideration

Although significant advances have been made in understanding the patho-physiology of psychiatric disorders (PDs), therapeutic advances have not been very convincing. While psychotropic medications can reduce classical symptoms in patients with PDs, their long-term use has been reported to induce or exaggerate various pre-existing metabolic abnormalities including diabetes, obesity and non-alcoholic fatty liver disease (NAFLD). The mechanism(s) underlying these metabolic abnormalities is not clear; however, lipid/fatty acid accumulation due to enhanced de novo lipogenesis (DNL) has been shown to reduce membrane fluidity, increase oxidative stress and inflammation leading to the development of the aforementioned metabolic abnormalities. Intriguingly, emerging evidence suggest that DNL dysregulation and fatty acid accumulation could be the major mechanisms associated with the development of obesity, diabetes and NAFLD after long-term treatment with psychotropic medications in patients with PDs. In support of this, several adjunctive drugs comprising of anti-oxidants and anti-inflammatory agents, that are used in treating PDs in combination with psychotropic medications, have been shown to reduce insulin resistance and development of NAFLD. In conclusion, the above evidence suggests that DNL could be a potential pathological factor associated with various metabolic abnormalities, and a new avenue for translational research and therapeutic drug designing in PDs.

From Bronchodilation to Lactic Acidosis: A Case Report on Salbutamol's Adverse Effect

Asthma is one of the most prevalent chronic respiratory diseases, characterized by bronchial hyper-responsiveness and intermittent airflow obstruction. Short-acting β2 agonists (SABA) remain the cornerstone of acute asthma management due to its properties in smooth muscle relaxation and bronchodilatation. Rarely, these drugs might be associated with adverse effects, including the development of metabolic and hydro-electrolytic imbalances. We report a case of lactic acidosis secondary to β2 agonists in a young female patient admitted with severe acute asthma. After initial management and significant improvement of the respiratory distress with nebulized and subcutaneous salbutamol, the patient developed high anion gap metabolic acidosis due to hyperlactacidemia and hypokalemia. Alternative causes of lactic acidosis were discarded, such as severe hypoxemia, systemic hypoperfusion, sepsis, and organ dysfunction, and SABA-related lactic acidosis was suspected. This treatment was halted, and tachypnea, metabolic acidosis, and lactate levels rapidly resolved. The remainder of the hospital stay was uneventful, and the patient was discharged after a period of five days. Although rare, the development of unexplained lactic acidosis in a SABA-treated patient should alert the treating physician to this β2 agonist side-effect.

Lactate-to-albumin ratio: A promising predictor of 28-day all-cause mortality in critically Ill patients with acute ischemic stroke

INTRODUCTION

Numerous diseases have been found to be associated with the lactate-to-albumin ratio (LAR), as confirmed by existing research. This study aims to investigate the relationship between LAR within 24 hours of admission and a 28-day mortality rate in patients manifesting ischemic stroke.

METHODS

This retrospective cohort study utilized data from the Medical Information Mart for Intensive Care IV (MIMIC-IV, version 2.1) database. We included adult patients with acute ischemic stroke (AIS) who were admitted to the intensive care unit. The primary outcome entailed evaluating the ability of LAR to predict death at 28-day of hospital admission in patients with AIS.

RESULTS

A total of 502 patients with ischemic stroke were enrolled in the study, of which 185 (36.9 %) died within 28 days after hospital admission. We identified a linear association between LAR and mortality risk. Compared with the reference group (first LAR tertile), the 28-day mortality was increased in the highest tertile; the fully adjusted HR value was 1.21 (1.08 to 1.40). the Area Under the Curve (AUC) value for LAR was 58.26 % (95 % CI: 53.05 % - 63.46 %), which was higher than that for arterial blood lactate (AUC = 56.88 %) and serum albumin (AUC = 55.29 %) alone. It was not inferior even when compared to SOFA (AUC = 56.28 %). The final subgroup analysis exhibited no significant interaction of LAR with each subgroup (P for interaction: 0.079 - 0.848).

CONCLUSION

In our study, LAR emerged as a promising predictor of all-cause mortality in acute ischemic stroke patients within 28 days of admission.

A case of pediatric Perthes' disease with unexplained hyperlactatemia at the time of initial surgery and anesthetic management with remimazolam for the subsequent surgery

BACKGROUND

The causes of perioperative hyperlactatemia vary, but they are generally associated with hypoperfusion. Here, we report the case of a pediatric patient who developed unexplained hyperlactatemia during anesthesia with propofol and sevoflurane, which recurred during a second surgery under anesthesia with remimazolam.

CASE PRESENTATION

An 8-year-old boy with Perthes disease and no remarkable past or family history was scheduled for an osteotomy. Anesthesia was induced with propofol and rocuronium and then maintained with sevoflurane and remifentanil. The patient developed lactic acidosis without hemodynamic instability during anesthesia, with a normal lactate/pyruvate ratio after surgery, suggesting a lack of hypoperfusion. We used remimazolam instead of propofol during the second surgery 6 months later, considering the possibility of drug-induced lactic acidosis, including malignant hyperthermia and propofol infusion syndrome, where the unexplained hyperlactatemia recurred.

CONCLUSIONS

Distinguishing the causes of hyperlactatemia, particularly in the absence of other symptoms, is challenging. The lactate/pyruvate ratio during episodes of hyperlactatemia can provide insights into the underlying pathology.

Relationship between lactate-to-albumin ratio and 28-day mortality in patients with exacerbation of chronic obstructive pulmonary disease admitted to the Intensive Care Unit

AIM

To explore the predictive value of lactate-to-albumin ratio (LAR) on 28-day mortality in patients with exacerbation of chronic obstructive pulmonary disease (AECOPD) admitted to the Intensive Care Unit (ICU).

METHODS

According to ICD-9 and ICD-10 diagnosis codes, patients diagnosed with AECOPD in the Medical Information Mart for Intensive Care IV (v.2.2) database were selected. The primary endpoint was 28-day mortality after ICU admission. We used receiver operating characteristic (ROC) curve, Kaplan-Meier (K-M) survival curve, logistic regression analyses and subgroup analysis to assess predictive power of LAR.

RESULTS

606 patients were included in this study. The 28-day mortality was 29.7%. The area under the ROC curves (AUC) for LAR were 0.641 [95% confidence interval (CI) 0.592-0.689], which was comparable with OASIS (AUC: 0.662; 95% CI 0.616-0.709; p = 0.471) and SOFA (AUC: 0.660; 95% CI 0.612-0.708; p = 0.500). The cutoff value of LAR was 0.645 by ROC curve. The high-LAR group showed a bad prognosis in K-M analysis (p < 0.001). Multivariate logistic regression shown that LAR was significantly associated with a poor outcome (odds ratio: 1.77; 95% CI 1.16-2.71; p = 0.008). Subgroup analysis showed no significant interaction of LAR with each subgroup (p for interaction: 0.175-0.775).

CONCLUSION

LAR is a rational and easily accessible marker, which is remarkably associated with 28-day mortality in ICU patients with AECOPD.

The usefulness of lactate/albumin ratio, C-reactive protein/albumin ratio, procalcitonin/albumin ratio, SOFA, and qSOFA in predicting the prognosis of patients with sepsis who presented to EDs

PURPOSE

Early identification of sepsis with a poor prognosis in the emergency department (ED) is crucial for prompt management and improved outcomes. This study aimed to examine the predictive value of sequential organ failure assessment (SOFA), quick SOFA (qSOFA), lactate to albumin ratio (LAR), C-reactive protein to albumin ratio (CAR), and procalcitonin to albumin ratio (PAR), obtained in the ED, as predictors for 28-day mortality in patients with sepsis and septic shock.

MATERIALS AND METHODS

We included 3499 patients (aged ≥19 years) from multicenter registry of the Korean Shock Society between October 2015 and December 2019. The SOFA score, qSOFA score, and lactate level at the time of registry enrollment were used. Albumin, C-reactive protein, and procalcitonin levels were obtained from the initial laboratory results measured upon ED arrival. We evaluated the predictive accuracy for 28-day mortality using the area under the receiver operating characteristic (AUROC) curve. A multivariable logistic regression analysis of the independent predictors of 28-day mortality was performed. The SOFA score, LAR, CAR, and PAR were converted to categorical variables using Youden's index and analyzed. Adjusting for confounding factors such as age, sex, comorbidities, and infection focus, adjusted odds ratios (aOR) were calculated.

RESULTS

Of the 3499 patients, 2707 (77.4%) were survivors, whereas 792 (22.6%) were non-survivors. The median age of the patients was 70 (25th-75th percentiles, 61-78), and 2042 (58.4%) were male. LAR for predicting 28-day mortality had the highest AUROC, followed by the SOFA score (0.715; 95% confidence interval (CI): 0.69-0.74 and 0.669; 95% CI: 0.65-0.69, respectively). The multivariable logistic regression analysis revealed that the aOR of LAR >1.52 was 3.75 (95% CI: 3.16-4.45), and the aOR, of SOFA score at enrollment >7.5 was 2.67 (95% CI: 2.25-3.17).

CONCLUSION

The results of this study showed that LAR is a relatively strong predictor of sepsis prognosis in the ED setting, indicating its potential as a straightforward and practical prognostic factor. This finding may assist healthcare providers in the ED by providing them with tools to risk-stratify patients and predict their mortality.

Norepinephrine versus epinephrine for hemodynamic support in post-cardiac arrest shock: A systematic review

PURPOSE

The preferred vasopressor in post-cardiac arrest shock has not been established with robust clinical outcomes data. Our goal was to perform a systematic review and meta-analysis comparing rates of in-hospital mortality, refractory shock, and hemodynamic parameters in post-cardiac arrest patients who received either norepinephrine or epinephrine as primary vasopressor support.

METHODS

We conducted a search of PubMed, Cochrane Library, and CINAHL from 2000 to 2022. Included studies were prospective, retrospective, or published abstracts comparing norepinephrine and epinephrine in adults with post-cardiac arrest shock or with cardiogenic shock and extractable post-cardiac arrest data. The primary outcome of interest was in-hospital mortality. Other outcomes included incidence of arrhythmias or refractory shock.

RESULTS

The database search returned 2646 studies. Two studies involving 853 participants were included in the systematic review. The proposed meta-analysis was deferred due to low yield. Crude incidence of in-hospital mortality was numerically higher in the epinephrine group compared with norepinephrine in both studies, but only statistically significant in one. Risk of bias was moderate to severe for in-hospital mortality. Additional outcomes were reported differently between studies, minimizing direct comparison.

CONCLUSION

The vasopressor with the best mortality and hemodynamic outcomes in post-cardiac arrest shock remains unclear. Randomized studies are crucial to remedy this.

The microcirculation in perioperative medicine: a narrative review

The microcirculation describes the network of the smallest vessels in our cardiovascular system. On a microcirculatory level, oxygen delivery is determined by the flow of oxygen-carrying red blood cells in a given single capillary (capillary red blood cell flow) and the density of the capillary network in a given tissue volume (capillary vessel density). Handheld vital videomicroscopy enables visualisation of the capillary bed on the surface of organs and tissues but currently is only used for research. Measurements are generally possible on all organ surfaces but are most often performed in the sublingual area. In patients presenting for elective surgery, the sublingual microcirculation is usually intact and functional. Induction of general anaesthesia slightly decreases capillary red blood cell flow and increases capillary vessel density. During elective, even major, noncardiac surgery, the sublingual microcirculation is preserved and remains functional, presumably because elective noncardiac surgery is scheduled trauma and haemodynamic alterations are immediately treated by anaesthesiologists, usually restoring the macrocirculation before the microcirculation is substantially impaired. Additionally, surgery is regional trauma and thus likely causes regional, rather than systemic, impairment of the microcirculation. Whether or not the sublingual microcirculation is impaired after noncardiac surgery remains a subject of ongoing research. Similarly, it remains unclear if cardiac surgery, especially with cardiopulmonary bypass, impairs the sublingual microcirculation. The effects of therapeutic interventions specifically targeting the microcirculation remain to be elucidated and tested. Future research should focus on further improving microcirculation monitoring methods and investigating how regional microcirculation monitoring can inform clinical decision-making and treatment.

The Significance of Microenvironmental and Circulating Lactate in Breast Cancer

Lactate represents the main product of pyruvate reduction catalyzed by the lactic dehydrogenase family of enzymes. Cancer cells utilize great quantities of glucose, shifting toward a glycolytic metabolism. With the contribution of tumor stromal cells and under hypoxic conditions, this leads toward the acidification of the extracellular matrix. The ability to shift between different metabolic pathways is a characteristic of breast cancer cells and is associated with an aggressive phenotype. Furthermore, the preliminary scientific evidence concerning the levels of circulating lactate in breast cancer points toward a correlation between hyperlactacidemia and poor prognosis, even though no clear linkage has been demonstrated. Overall, lactate may represent a promising metabolic target that needs to be investigated in breast cancer.

The Warburg effect in patients with brain tumors: a comprehensive analysis of clinical significance

PURPOSE

The Warburg Effect, referring to an elevation in serum lactate level attributable to increased tumor metabolism, is present in patients with brain tumors. This study comprehensively analyzes the Warburg effect in patients undergoing brain tumor resection.

METHODS

We retrospectively analyzed the baseline intraoperative serum lactate levels of 2,053 patients who underwent craniotomies, including 415 with cerebral aneurysms and 1,638 with brain tumors. The brain tumor group was divided into subgroups based on the tumor pathology (extra-axial and intra-axial tumor) and the WHO tumor grade (high-grade and low-grade).

RESULTS

Serum lactate level was significantly higher in the tumor group than in the aneurysm group (1.98 ± 0.97 vs. 1.09 ± 0.57 mmol/L, p < 0.001). The hyperlactatemia incidence (serum lactate level > 2.2 mmol/L) was higher in the tumor group (33.5 vs. 3.1%, p < 0.001). Severe hyperlactatemia (serum lactate level > 4.4 mmol/L) was found in 34 patients (2.1%) of only the tumor group. In patients with intra-axial tumors, serum lactate level was greater in high- than low-grade tumors (2.10 ± 1.05 vs. 1.88 ± 0.92 mmol/L, p = 0.006). Factors predictive of hyperlactatemia included supratentorial tumor location (odds ratio[95%CI] 2.926[2.127-4.025], p < 0.001) and a long tumor diameter (1.071[1.007-1.139], p = 0.028). In high-grade intra-axial brain tumor patients, there was a significant difference in overall survival between patients with hyperlactatemia than those without (p = 0.048).

CONCLUSION

Our results show that brain tumor patients exhibit the Warburg effect and serum lactate may be a useful diagnostic and prognostic biomarker in patients with high-grade intra-axial brain tumors.

The lactate to albumin ratio linked to all-cause mortality in critically ill patients with septic myocardial injury

Background

The lactate to albumin ratio (LAR) has emerged as a promising prognostic marker in critically ill patients. Despite its potential utility, the prognostic value of LAR in septic myocardial injury (SMI) remains uncertain.

Methods

This study aims to investigate the prognostic significance of LAR in SMI through a retrospective cohort analysis of data from the Medical Information Mart for Intensive Care III (MIMIC-III) (v1.4) database. The study included intensive care unit (ICU)-admitted patients (age ≥18 years) diagnosed with SMI. The primary endpoint was in-hospital mortality.

Results

A total of 704 patients were included in the study, of which 59.10% were male. Hospital mortality and ICU mortality rates were recorded at 29.97% and 22.87%, respectively. After adjusting for confounding factors, multivariate Cox proportional risk analysis demonstrated that LAR was independently associated with an increased risk of both hospital mortality (HR, 1.39 [95% CI: 1.24-1.56] P < 0.001) and ICU mortality (HR, 1.46 [95% CI: 1.29-1.65] P < 0.001). Furthermore, the generalized additive model (GAM) and restricted cubic spline (RCS) model indicated a linear relationship between LAR and mortality rates in the ICU and hospital.

Conclusions

The LAR may serve as a potential prognostic biomarker in critically ill patients with SMI. High LAR levels are associated with a higher risk of in-hospital mortality and can help identify individuals with high mortality rates. Overall, the findings emphasize the importance of using LAR as a tool for risk stratification and management of critically ill patients with SMI.

Type B Lactic Acidosis in a Patient with Mantle Cell Lymphoma

Type B lactic acidosis is an uncommon medical emergency in which acid production overwhelms hepatic clearance. This specific etiology of lactic acidosis occurs without organ hypoperfusion and has been most commonly described in patients with hematologic malignancies but also in patients with solid tumors. The mechanism by which cancer cells switch their glucose metabolism toward increasingly anaerobic glycolytic phenotypes has been described as the "Warburg effect." Without treating the underlying malignancy, the prognosis for patients diagnosed with malignancy-related type B lactic acidosis is extremely poor. Here, we present a case of a 66-year-old male who was diagnosed with type B lactic acidosis secondary to mantle cell lymphoma. Bicarbonate drip was started to correct the lactic acidosis. The patient was also immediately treated with rituximab chemotherapy combined with rasburicase to avoid the hyperuricemia associated with tumor lysis syndrome. He responded to the early treatment and was discharged with normal renal function. Type B lactic acidosis secondary to hematologic malignancy is important to recognize. In order to successfully treat this syndrome, early diagnosis and simultaneous treatment of the imbalance of lactic acid levels and the underlying malignancy are necessary.

The Association Between Hypophosphatemia and Lactic Acidosis After Cardiac Surgery With Cardiopulmonary Bypass: A Retrospective Cohort Study

OBJECTIVES

The clinical significance of hypophosphatemia in cardiac surgery has not been investigated extensively. The aim of this study was to evaluate the association of postoperative hypophosphatemia and lactic acidosis in cardiac surgery patients at the time of intensive care unit (ICU) admission.

DESIGN

A retrospective cohort study.

SETTING

At a single academic center.

PARTICIPANTS

Patients who underwent nontransplant cardiac surgery with cardiopulmonary bypass between August 2009 and December 2020.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Serum phosphate and lactate levels were measured upon ICU admission in patients undergoing nontransplant cardiac surgery with cardiopulmonary bypass. There were 681 patients in the low-phosphate (<2.5 mg/dL) group and 2,579 patients in the normal phosphate group (2.5-4.5 mg/dL). A higher proportion of patients in the low phosphate group (26%; 179 of 681; 95% CI: 23-30) had severe lactic acidosis compared to patients in the normal phosphate group (16%; 417 of 2,579; 95% CI: 15-18). In an unadjusted logistic regression model, patients in the low phosphate group had 1.9-times the odds of having severe lactic acidosis (serum lactate ≥4.0 mmol/L) when compared to patients in the normal phosphate group (95% CI: 1.5-2.3), and still 1.4-times the odds (95% CI: 1.1-1.7) after adjusting for several possible confounders.

CONCLUSIONS

Hypophosphatemia is associated with lactic acidosis in the immediate postoperative period in cardiac surgery patients. Future studies will need to investigate it as a potential treatment target for lactic acidosis.

Enalapril increases the urinary excretion of metformin in rats by inducing multidrug and toxin excretion protein 1 in the kidney

Two-thirds of patients with type 2 diabetes mellitus have hypertension, and thus the combination of two or more drugs to treat these diseases is common. It has been shown that the combination of metformin and enalapril has beneficial effects, but few studies have evaluated the interactions between these two drugs. This study investigated the effects of enalapril on the pharmacokinetics and urinary excretion of metformin in rats, with a focus on transporter-mediated drug interactions. Rats were dosed orally with metformin alone (100 mg/kg) or in combination with enalapril (4 mg/kg). The concentration of metformin was measured by high performance liquid chromatography and the level of organic cation transporters (rOCTs) and multidrug and toxin excretion protein 1 (rMATE1), which mediate the uptake and efflux of metformin, respectively, were evaluated by immunoblotting. After single and 7-day dosing, the plasma concentration of metformin in the co-administration group was significantly lower than that in the metformin-only group, and the CL/F and urinary excretion were increased in the co-administration group. Enalapril did not affect the K_p of metformin but reduced renal slice-uptake of metformin. The expression of rMATE1 was increased, whereas rOCT2 expression was decreased in rat kidney. Importantly, long-term co-administration of metformin and enalapril markedly decreased the level of lactic acid and uric acid in the blood. Enalapril increases the urinary excretion of metformin through the up-regulation of rMATE1. This reveals a new mechanism of drug interactions and provides a basis for drug dosage adjustment when these drugs are co-administered.

Lactate Production can Function to Increase Human Epithelial Cell Iron Concentration

Introduction

Under conditions of limited iron availability, plants and microbes have evolved mechanisms to acquire iron. For example, metal deficiency stimulates reprogramming of carbon metabolism, increasing activity of enzymes involved in the Krebs cycle and the glycolytic pathway. Resultant carboxylates/hydroxycarboxylates then function as ligands to complex iron and facilitate solubilization and uptake, reversing the metal deficiency. Similarly, human intestinal epithelial cells may produce lactate, a hydroxycarboxylate, during absolute and functional iron deficiency to import metal to reverse limited availability.

Methods

Here we investigate (1) if lactate can increase cell metal import of epithelial cells in vitro, (2) if lactate dehydrogenase (LDH) activity in and lactate production by epithelial cells correspond to metal availability, and (3) if blood concentrations of LDH in a human cohort correlate with indices of iron homeostasis.

Results

Results show that exposures of human epithelial cells, Caco-2, to both sodium lactate and ferric ammonium citrate (FAC) increase metal import relative to FAC alone. Similarly, fumaric, isocitric, malic, and succinic acid coincubation with FAC increase iron import relative to FAC alone. Increased iron import following exposures to sodium lactate and FAC elevated both ferritin and metal associated with mitochondria. LDH did not change after exposure to deferoxamine but decreased with 24 h exposure to FAC. Lactate levels revealed decreased levels with FAC incubation. Review of the National Health and Nutrition Examination Survey demonstrated significant negative relationships between LDH concentrations and serum iron in human cohorts.

Conclusions

Therefore, we conclude that iron import in human epithelial cells can involve lactate, LDH activity can reflect the availability of this metal, and blood LDH concentrations can correlate with indices of iron homeostasis.

Lactic Acidosis in Patients with Solid Cancer

Significance: Cancer-associated tissue-specific lactic acidosis stimulates and mediates tumor invasion and metastasis and is druggable. Rarely, malignancy causes systemic lactic acidosis, the role of which is poorly understood. Recent Advances: The understanding of the role of lactate has shifted dramatically since its discovery. Long recognized as only a waste product, lactate has become known as an alternative metabolism substrate and a secreted nutrient that is exchanged between the tumor and the microenvironment. Tissue-specific lactic acidosis is targeted to improve the host body's anticancer defense and serves as a tool that allows the targeting of anticancer compounds. Systemic lactic acidosis is associated with poor survival. In patients with solid cancer, systemic lactic acidosis is associated with an extremely poor prognosis, as revealed by the analysis of 57 published cases in this study. Although it is considered a pathology worth treating, targeting systemic lactic acidosis in patients with solid cancer is usually inefficient. Critical Issues: Research gaps include simple questions, such as the unknown nuclear pH of the cancer cells and its effects on chemotherapy outcomes, pH sensitivity of glycosylation in cancer cells, in vivo mechanisms of response to acidosis in the absence of lactate, and overinterpretation of in vitro results that were obtained by using cells that were not preadapted to acidic environments. Future Directions: Numerous metabolism-targeting anticancer compounds induce lactatemia, lactic acidosis, or other types of acidosis. Their potential to induce acidic environments is largely overlooked, although the acidosis might contribute to a substantial portion of the observed clinical effects. Antioxid. Redox Signal. 37, 1130-1152.

Lactic Acidosis Related to Pharmacotherapy and Human Diseases

Lactic acidosis represents one of the most common conditions that can compromise the health of intensive care unit (ICU) patients, increasing the mortality of patients with high levels of Lactate who do not receive a proper treatment within the first 6 h of hospitalization. There are two enantiomers of lactic acid: L-lactic acid (when the concentration increases, it can lead to a state of severe acidemia risking cardiovascular collapse, causing an increase in mortality in ICU patients) and D lactic acid (produced in the human organism by microbiota and its production increases during some pathological status). Generally, increased levels of serum lactic acid could be due to numerous factors, including hypoxia (caused for example by septic/cardiogenic/hypovolemic or obstructive shock), specific pathologies (e.g., liver disease), use of some drugs (e.g., metformin), presence of toxins, and trauma. Since the underlying cause could be fatal for the ICU patient, it is important to understand the root of this clinical status with a view to correct it and prevent the risk of a poor clinical outcome. Prevention and early treatment are the keys to control the negative clinical consequences. The aim of this review is to revise the scientific literature for further confirmation about the importance of early identification of acidotic statuses and to underline how an early diagnosis can prevent the worst clinical outcome, especially for ICU patients who are more fragile compared to the general population.

Association of lactate to albumin ratio and bicarbonate with short-term mortality risk in patients with acute myocardial infarction

BACKGROUND

Previous studies have indicated that the ratio of lactate/albumin (L/A) has predictive value for the prognosis of critically ill patients with heart failure. Some studies have also indicated that a low serum bicarbonate concentration is inversely related to the mortality risk of patients with cardiogenic shock. However, the value of bicarbonate and the L/A ratio for predicting the mortality risk of patients with acute myocardial infarction (AMI) is still unclear. We therefore conducted a retrospective study to research this problem.

METHODS

The subjects of this study were patients with AMI, and the data source was the Medical Information Mart for Intensive Care III database. The primary endpoint was 30-day all-cause mortality after admission. The Receiver operating characteristic (ROC) curve was used to compare the predictive value of L/A ratio, lactate and albumin for end-point events. The effects of different L/A ratio levels and different bicarbonate concentrations on 7-day and 30-day all-cause mortality were compared using Kaplan-Meier (K-M) curves. Hazard ratios for different L/A ratio and different bicarbonate concentrations were investigated using COX proportional hazards models.

RESULTS

The Area Under Curve (AUC) of L/A ratio, lactate, and albumin were 0.736, 0.718, and 0.620, respectively. (1) L/A ratio: The patients were divided into three groups according to their L/A ratio: tertile T1 (L/A ratio ≤ 0.47), tertile T2 (L/A ratio ≤ 0.97), and tertile T3 (L/A ratio > 0.97). The T2 and T3 groups had higher 30-day all-cause mortality risks than the T1 group. The restricted cubic spline (RCS) model indicated that there was a nonlinear relationship between L/A ratio and 30-day mortality (P < 0.05). (2) Bicarbonate concentration: The patients were also divided into three groups based on their bicarbonate concentration: G1 (22-27 mmol/L), G2 (< 22 mmol/L), and G3 (> 27 mmol/L). The G2 and G3 groups had higher 30-day all-cause mortality risks than the G1 group. The RCS model indicated that there was a nonlinear relationship between bicarbonate concentration and 30-day mortality (P < 0.05). The RCS model indicated that there was a nonlinear relationship between hemoglobin level and 30-day all-cause mortality (P < 0.05).

CONCLUSION

L/A ratio and bicarbonate concentration and hemoglobin level have predictive value for predicting 30-day mortality in patients with acute myocardial infarction.

Risk Factors and Consequences of Late-Onset Hyperlactatemia After Cardiac Surgery With Cardiopulmonary Bypass: A Single-Center Retrospective Study

OBJECTIVE

Mechanisms and consequences of late-onset hyperlactatemia after cardiac surgery remain unclear. The aim of this study was to identify risk factors and outcomes of late hyperlactatemia, defined as a lactate value ≥3 mmol/L developing in the intensive care unit (ICU) after not being elevated on admission after cardiac surgery with cardiopulmonary bypass.

DESIGN

A retrospective analysis of prospectively collected data.

SETTING

A single-center University Hospital.

PARTICIPANTS

Patients who underwent elective cardiac surgery with cardiopulmonary bypass in 2019 and who had normal lactatemia at ICU admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patients were divided in 2 groups according to their lactatemia on postoperative day 1 (14.0 ± 3.0 hours after ICU admission): normal lactatemia (control group) and late hyperlactatemia (HL group). Risk factors for late hyperlactatemia were identified using a multivariate analysis, and postoperative outcomes were compared using a composite criterion of severe outcomes. Of the 432 included patients, 37 (8.5%) presented with late hyperlactatemia. Risk factors independently associated with hyperlactatemia were afternoon surgery (odds ratio [OR] 4.24, 95% CI 2.00-9.35), a bleeding >300 mL within the 6 hours after surgery (H6) (OR 3.77, 95% CI 1.71-8.30), and H6 fluid loading >250 mL (OR 2.64, 95% CI 1.22-5.55). Patients with hyperlactatemia presented more frequently with major postoperative complications, including acute kidney injury, and received more frequent red-cell transfusion.

CONCLUSION

The strongest risk factors associated with late-onset hyperlactatemia in the authors' population were afternoon surgery and H6 bleeding >300 mL. Poor postoperative outcomes were more frequent in patients with late hyperlactatemia, even in the absence of early hyperlactatemia or severe obvious condition.

Comparison of lactate/albumin ratio to lactate and lactate clearance for predicting outcomes in patients with septic shock admitted to intensive care unit: an observational study

The aim of this study was to evaluate the prognostic value of the Lactate to Albumin (L/A) ratio compared to that of lactate and lactate clearance in predicting outcomes in patients with septic shock. This was a multi-center observational study of adult patients with septic shock, who admitted to intensive care units (ICUs) at Shohada and Imam Reza Hospitals, Tabriz, Iran, between Sept 2018 and Jan 2021. The area under the curve (AUC) of receiver operating characteristic (ROC) curve and multivariate logistic regression analyses were used to explore associations of the L/A ratio, lactate and lactate clearance on the primary (mortality) and secondary outcomes [ICU length of stay (LOS), duration of mechanical ventilation (MV), need of renal replacement therapy (RRT) and duration of using vasopressors] at baseline, 6 h and 24 h of septic shock recognition. Best performing predictive value for mortality were related to lactate clearance at 24 h, L/A ratio at 6 h and lactate levels at 24 h with (AUC 0.963, 95% CI 0.918-0.987, P < 0.001), (AUC 0.917, 95% CI 0.861-0.956, P < 0.001), and (AUC 0.904, 95% CI 0.845-0.946, P < 0.001), respectively. Generally, the lactate clearance at 24 h had better prognostic performance for mortality and duration of using vasopressor. However, the L/A ratio had better prognostic performance than serum lactate and lactate clearance for RRT, ICU LOS and MV duration.

Severe lactic acidosis and persistent diastolic hypotension following standard dose of intermittent nebulized salbutamol in a child: a case report

Background

Salbutamol is a selective β2-receptor agonist widely used to treat asthma in both emergency and outpatient settings. However, it has been associated with a broad spectrum of side effects. Lactic acidosis and diastolic hypotension are rarely reported together following intermittent salbutamol nebulization in children, even less so at standard therapeutic doses.

Case presentation

We present the case of a 12-year-old Italian boy, 34 kg body weight, who experienced a serious drug reaction during a moderate asthma exacerbation with associated dehydration (blood urea nitrogen/creatinine 0.25), following intermittent inhaled (0.2 mg at 3-hour intervals—overall 1.4 mg in 24 hours before arrival) and nebulized treatment (3.25 mg at 20-minute intervals in 60 minutes, overall 11.25 mg in our emergency department). The patient developed hyperglycemia (peak concentration 222 mg/dL), hypokalemia (lowest concentration 2.6 mEq/L), electrocardiogram alterations (corrected QT interval 467 ms), long-lasting arterial hypotension despite fluid boluses (lowest value 87/33 mmHg), and elevated blood lactate levels (peak concentration 8.1 mmol/L), following the third nebulized dose. Infections, liver dysfunction, and toxicity following other medications were ruled out. The aforementioned alterations improved within 24 hours after discontinuation of salbutamol.

Conclusions

We reinforce the message that even the use of intermittent nebulized salbutamol for acute moderate asthma can lead to severe transient complications in children. Then, healthcare providers should pay attention not only in emergency settings, to achieve prompt recognition and proper management of this adverse reaction. Careful reassessment could prevent similar reactions.

The prognostic value of the lactate/albumin ratio for predicting mortality in septic patients presenting to the emergency department: a prospective study

OBJECTIVES

Lactate/albumin (L/A) ratio is a biomarker in sepsis that has been shown to outperform lactate. This prospective study aims to validate the superior prognostic value of the L/A ratio to lactate in sepsis and septic shock.

METHODS

Prospective cohort conducted from September 2018 till February 2021 on adult patients presenting to the Emergency Department (ED) at a tertiary care centre with sepsis or septic shock. The primary outcome was the prognostic value of the L/A ratio compared to lactate with regards to mortality.

RESULTS

A total of 939 septic patients were included throughout the study period. A total of 236 patients developed septic shock. The AUC value of the L/A ratio in septic patients was 0.65 (95% CI 0.61-0.70) and was higher than that of lactate alone 0.60 (95% CI 0.55-0.64) with a p < .0001. The optimal L/A ratio cut-off threshold that separated survivors from non-survivors was found to be 0.115 for all septic patients. The AUC of the L/A ratio was significantly higher for patients with a lactate ≥2 mmol/L: 0.69 (95% CI 0.64-0.74) versus 0.60 (95% CI 0.54-0.66) with a p < .0001 as well as for patients with an albumin level less than 30 g/L (AUC = 0.69 95% CI= 0.62-0.75 vs AUC= 0.66 95% CI= 0.59-0.73, p = .04). Among septic shock patients there was no statically significant difference in the AUC value of the L/A ratio compared to lactate (0.53 95% CI 0.45-0.61 vs 0.50 95% CI 0.43-0.58 respectively with a p-value = .11).

CONCLUSIONS

The L/A ratio is a better predictor of in-patient mortality than lactate in sepsis patients. This superiority was not found in the septic shock subgroup. Our results encourage the use of the ratio early in the ED as a superior prognostic tool in sepsis patients.Key messagesWe aimed to assess the prognostic usefulness of the Lactate/Albumin ratio compared to lactate alone in septic and septic shock patients.The L/A ratio proved to be a better predictor of in-patient mortality than lactate alone in sepsis patients. This pattern also applies across various subgroups in our study (malignancy, diabetics, age above 65, lactate level less than 2 mmol/L, albumin less than 30 g/L). Our results favour the use of the L/A ratio over lactate alone in patients with sepsis and the previously mentioned subgroups.Our results do not favour the use of the ratio instead of lactate in septic shock patients as there was no statistically significant difference between the AUCs of the ratio and lactate alone.

Albuterol, Acidosis, and Aneurysms

A patient with a complicated medical history on admission for dyspnea was administered nebulizer therapy but after 72 hours developed asymptomatic acute kidney injury and anion-gap metabolic acidosis.

Salbutamol-induced lactic acidosis in status asthmaticus survivor

Background

Salbutamol-induced lactic acidosis is a rare presentation that could manifest in specific clinical context as acute asthmatic attack treatment. An increase of glycolysis pathway leading to pyruvate escalation is the mechanism of hyperlactatemia in β2-adrenergic agonist drug.

Case presentation

A 40-year-old man who had poor-controlled asthma, presented with progressive dyspnea with coryza symptom for 6 days. He was intubated and admitted into medical intensive care unit due to deteriorated respiratory symptom. Severe asthmatic attack was diagnosed and approximate 1.5 canisters of salbutamol inhaler was administrated within 24 h of admission. Initial severe acidosis consisted of acute respiratory acidosis from ventilation-perfusion mismatch and acute metabolic acidosis resulting from bronchospasm and hypoxia-related lactic acidosis, respectively. The lactate level was normalized in 6 h after hypoxemia and ventilation correction. Given the lactate level re-elevated into a peak of 4.6 mmol/L without signs of tissue hypoxia nor other possible etiologies, the salbutamol toxicity was suspected and the inhaler was discontinued that contributed to rapid lactate clearance. The patient was safely discharged on the 6th day of admission.

Conclusion

The re-elevation of serum lactate in status asthmaticus patient who had been administrated with the vast amount of β2-adrenergic agonist should be considered for salbutamol-induced lactic acidosis and promptly discontinued especially when there were no common potentials.

Lactate/Albumin Ratio as a Predictor of In-Hospital Mortality in Septic Patients Presenting to the Emergency Department

Background: The aim of this study is to evaluate the prognostic value of the Lactate to Albumin (L/A) ratio compared to that of lactate only in predicting morbidity and mortality in sepsis patients.

Methods: This was a single-center retrospective cohort study. All adult patients above the age of 18 with a diagnosis of sepsis who presented between January 1, 2014 and June 30, 2019 were included. The primary outcome was in-hospital mortality.

Results: A total of 1,381 patients were included, 44% were female. Overall in-hospital mortality was 58.4% with the mortalities of sepsis and septic shock being 45.8 and 67%, respectively. 55.5% of patients were admitted to the intensive care unit. The area under the curve value for lactate was 0.61 (95% CI 0.57–0.65, p < 0.001) and for the L/A ratio was 0.67 (95% CI 0.63–0.70, p < 0.001). The cutoff generated was 1.22 (sensitivity 59%, specificity 62%) for the L/A ratio in all septic patients and 1.47 (sensitivity 60%, specificity 67%) in patients with septic shock. The L/A ratio was a predictor of in-hospital mortality (OR 1.53, CI 1.32–1.78, p < 0.001).

Conclusion: The L/A ratio has better prognostic performance than initial serum lactate for in-hospital mortality in adult septic patients.

Selective ß2-Adrenoceptor Agonists and Relevant Hyperlactatemia: Systematic Review and Meta-Analysis

Selective ß₂-agonists have been imputed as potential cause of l-hyperlactatemia since the 1970s. To document the prevalence of hyperlactatemia associated with selective ß₂-agonists and to investigate the predisposing factors, we searched for published articles until April 2019 pertaining to the interplay of administration of selective ß₂-agonists and circulating l-lactic acid in the Excerpta Medica, Web of Science, and the U.S. National Library of Medicine databases. Out of the 1834 initially retrieved records, 56 articles were included: 42 papers reporting individual cases, 2 observational studies, and 12 clinical trials. Forty-seven individual patients receiving a selective ß₂-agonist were found to have l-lactatemia ≥5.0 mmol/L, which decreased by ≥3.0 mmol/L or to ≤2.5 mmol/L after discontinuing (N = 24), reducing (N = 17) or without modifying the dosage of the selective ß₂-agonist (N = 6). Clinical trials found that l-lactic acid significantly increased in healthy volunteers administered a ß₂-agonist. l-lactatemia ≥5.0 mmol/L was observed in 103 (24%) out of 426 patients with asthma or preterm labor managed with a selective ß₂-agonist and was more common in patients with asthma (30%) than in premature labor (5.9%). A significant relationship was also noted between l-lactate level and intravenous albuterol dose or its circulating level. In conclusion, relevant l-hyperlactatemia is common on high dose treatment with a selective ß₂-agonist.