Demystifying Lactate in the Emergency Department

Association of prehospital lactate levels with base excess in various emergencies - a retrospective study

OBJECTIVES

Blood gas analysis, including parameters like lactate and base excess (BE), is crucial in emergency medicine but less commonly utilized prehospital. This study aims to elucidate the relationship between lactate and BE in various emergencies in a prehospital setting and their prognostic implications.

METHODS

We conducted a retrospective analysis of prehospital emergency patients in Graz, Austria, from October 2015 to November 2020. Our primary aim was to assess the association between BE and lactate. This was assessed using Spearman's rank correlation and fitting a multiple linear regression model with lactate as the outcome, BE as the primary covariate of interest and age, sex, and medical emergency type as confounders.

RESULTS

In our analysis population (n=312), lactate and BE levels were inversely correlated (Spearman's ρ, -0.75; p<0.001). From the adjusted multiple linear regression model (n=302), we estimated that a 1 mEq/L increase in BE levels was associated with an average change of -0.35 (95 % CI: -0.39, -0.30; p<0.001) mmol/L in lactate levels. Lactate levels were moderately useful for predicting mortality with notable variations across different emergency types.

CONCLUSIONS

Our study highlights a significant inverse association between lactate levels and BE in the prehospital setting, underscoring their importance in early assessment and prognosis in emergency care. Additionally, the findings from our secondary aims emphasize the value of lactate in diagnosing acid-base disorders and predicting patient outcomes. Recognizing the nuances in lactate physiology is essential for effective prehospital care in various emergency scenarios.

Cardiac Tamponade Due to Intrapericardial Hernia Mimicking ST-Segment Elevation Myocardial Infarction

Intrapericardial hernia is a diaphragmatic hernia that extremely rarely causes cardiac tamponade. We present a case of a cardiac tamponade caused by an intrapericardial hernia in a 78-year-old male patient with a history of coronary artery bypass grafting, mimicking ST-segment elevation myocardial infarction, which was successfully treated by emergent laparotomy.

Association between preoperative lactate level and early complications after surgery for isolated extremity fracture

BACKGROUND

The role of lactate level in selecting the timing of definitive surgery for isolated extremity fracture remains unclear. Therefore, we aimed to elucidate the use of preoperative lactate level for predicting early postoperative complications.

METHODS

This was a single-center retrospective observational study of patients with isolated extremity fracture who underwent orthopedic surgery. Patients who underwent lactate level assessment within 24 h prior to surgery were included. The incidence of early postoperative complications was compared between patients with a preoperative lactate level of ≥ 2 and < 2 mmol/L. Moreover, subgroup analyses were performed based on the time from hospital arrival to surgery and fracture type.

RESULTS

In total, 187 patients were included in the study. The incidence of postoperative complications was significantly higher in patients with a preoperative lactate level of ≥ 2 mmol/L than those with a preoperative lactate level of < 2 mmol/L. This result did not change after adjusting for age and severity. Further, a high preoperative lactate level was associated with a greater incidence of postoperative complications in patients who underwent definitive surgery within 6 h after arrival.

CONCLUSION

A preoperative lactate level of ≥ 2 mmol/L was associated with a greater incidence of early postoperative complications in isolated extremity fractures. Nevertheless, this correlation was only observed among patients who underwent definitive fixation within 6 h after hospital arrival.

The Relationship Between Lactate and Lactate Clearance with In-Hospital Mortality in Unselected Emergency Department Patients

INTRODUCTION

Lactate is a frequently used biomarker in emergency departments (EDs), especially in critically ill patients. The aim of this study is to investigate the relationship between lactate and lactate clearance with in-hospital mortality in unselected ED patients.

METHODS

This study was carried out retrospectively in the ED of a tertiary hospital. Patients aged 18 years and older whose blood lactate level was obtained in the ED were included in the study. Patients whose lactate value did not have sufficient analytical accuracy, whose lactate value was recorded in the system 180 minutes after admission, who were admitted to the ED as cardiac arrest, and whose ED or hospital outcome was unknown were excluded from the study. According to the first measured lactate value, the patients were divided into three groups: < 2.0mmol/L, 2.0-3.9mmol/L, and ≥ 4.0mmol/L. Lactate clearance was calculated and recorded in patients with one-to-four hours between two lactate values.

RESULTS

During the five-year study period, a total of 1,070,406 patients were admitted to the ED, of which 114,438 (10.7%) received blood gas analysis. The median age of 81,449 patients included in the study was 58 years (IQR: 30, min: 18-max: 117) and 54.4% were female. The study found that non-trauma patients with a lactate level between 2.0-3.9mmol/L had a 2.5-times higher mortality risk, while those with a lactate level of ≥ 4.0mmol/L had a 20.8-times higher risk, compared to those with a lactate level < 2.0mmol/L. For trauma patients, the mortality risk was three-times higher for those with lactate levels between 2.0-3.9mmol/L and nine-times higher for those with a lactate level of ≥ 4.0mmol/L, compared to those with a lactate level < 2.0mmol/L. Among patients with a first measured lactate value ≥ 4.0mmol/L and a two-hour lactate clearance < 20%, the mortality rate was 19.7%. In addition, lactate, lactate clearance, and age were independent variables for mortality in this patient group.

CONCLUSION

The lactate value in unselected patients in the ED is a biomarker that can be used to predict the prognosis of the patients. In addition, lactate, lactate clearance, and age are independent predictors of mortality.

Evaluation of Blood Lactate, Heart Rate, Blood Pressure, and Shock Index, and Their Association with Prognosis in Calves

Diseases in young calves received as emergencies are often associated with hypovolemic and/or septic shocks. The objectives of our study were to (1) assess the correlation between clinical hemodynamic parameters and blood L-lactates (LAC), systolic blood pressure (SBP), and the shock index (SI) recorded upon arrival; and (2) to evaluate how these parameters were related to short-term outcomes in calves under 4 months of age presented as emergencies. We conducted a single-observer prospective observational study on calves aged from 1 day to 4 months, presented to the Veterinary Clinic for Ruminants of Liège from December 2020 to May 2022. Forty-five calves were included in the study. The statistical analysis revealed a significant correlation between LAC and heart rate (r = 0.570; p < 0.05) and LAC and SI (r = 0.373; p < 0.05). A high LAC value at admission was significantly associated with a negative outcome (death) (p < 0.05). In calves suffering from obstructive digestive diseases, the SI was related to the outcome and the analysis indicated a cut-off value of 1.13 (Se = 0.77, Spe = 1). In conclusion, in our study, the initial blood L-lactate value was correlated with heart rate, the shock index, and the clinical shock score, and admission hyperlactatemia was associated with a poor prognosis in calves under 4 months of age. In this cohort, the shock index in calves suffering from digestive diseases was linked with mortality.

The synergism of cytosolic acidosis and reduced NAD+/NADH ratio is responsible for lactic acidosis-induced vascular smooth muscle cell impairment in sepsis

BACKGROUND

During sepsis, serve vascular dysfunctions lead to life-threatening multiple organ failure, due to vascular smooth muscle cells (VSMC) impairments, resulting in vasoplegia, hypotension and hypoperfusion. In addition, septic patients have an altered cell metabolism that leads to lactic acidosis. Septic patients suffering from lactic acidosis have a high risk of mortality. In addition, septic survivors are at risk of secondary vascular disease. The underlying mechanisms of whether and how lactic acidosis leads to the changes in VSMCs is not well understood. The aim of this study was to comprehensively investigate the effect of lactic acidosis on VSMCs and additionally compare the effects with those induced by pure acidosis and sodium lactate.

METHODS

Primary human aortic smooth muscle cells (HAoSMCs) were treated for 48 h with lactic acidosis (LA_pH 6.8), hydrochloric acid (HCl_pH 6.8), sodium lactate (Na+-lactate_pH 7.4) and the respective controls (ctrl._pH 7.4; hyperosmolarity control: mannitol_pH 7.4) and comparatively analyzed for changes in (i) transcriptome, (ii) energy metabolism, and (iii) phenotype.

RESULTS

Both types of acidosis led to comparable and sustained intracellular acidification without affecting cell viability. RNA sequencing and detailed transcriptome analysis revealed more significant changes for lactic acidosis than for hydrochloric acidosis, with lactate being almost ineffective, suggesting qualitative and quantitative synergism of acidosis and lactate. Bioinformatic predictions in energy metabolism and phenotype were confirmed experimentally. Lactic acidosis resulted in strong inhibition of glycolysis, glutaminolysis, and altered mitochondrial respiration which reduced cellular ATP content, likely due to increased TXNIP expression and altered NAD+/NADH ratio. Hydrochloric acidosis induced significantly smaller effects without changing the NAD+/NADH ratio, with the ATP content remaining constant. These metabolic changes led to osteo-/chondrogenic/senescent transdifferentiation of VSMCs, with the effect being more pronounced in lactic acidosis than in pure acidosis.

CONCLUSIONS

Overall, lactic acidosis exerted a much stronger effect on energy metabolism than pure acidosis, whereas lactate had almost no effect, reflecting the qualitative and quantitative synergism of acidosis and lactate. As a consequence, lactic acidosis may lead to acute functional impairments of VSMC, sustained perturbations of the transcriptome and cellular dedifferentiation. Moreover, these effects may contribute to the acute and prolonged vascular pathomechanisms in septic patients.

Oncostatin M for characterizing the inflammatory burden and outcome of V-V ECMO in ARDS patients

BACKGROUND

Assessing the outcome of Veno-Venous Extracorporeal Membrane Oxygenation (V-V ECMO) support remains challenging as plasma lactate (pLA), the widely used tool for this purpose, has been shown unreliable. We hypothesized that plasma oncostatin M (pOSM), a sensitive marker of leukocyte activation in infection and inflammation, could address this deficiency.

METHODS

Plasma OSM levels were measured by ELISA in 30 Acute Respiratory Distress Syndrome (ARDS) patients, prior to cannulation (baseline) and decannulation.

RESULTS

Based on the absolute pOSM levels at presentation, patients were separated into two groups, A and B. Patients in group A had low pOSM levels (Mean ± SD; Median, 1.1 ± 3.8; 0 pg/mL), whereas group B had high pOSM levels (1548 ± 1999; 767 pg/mL) [t-test: p < 0.01]. The percentage of pOSM levels at decannulation relative to baseline OSM levels was significantly higher in those who died (116.8 ± 68.0; 85.3%) than those who survived (47.6 ± 25.5; 48.9%) [t-test: p = 0.02; Mann-Whitney U Test: p = 0.01]. Conversely, no significant difference was observed in the percentage of pLA levels between those who died (142.9 ± 179.9; 89.8%) and those who survived (79.3 ± 34.3; 81.8%) [t-test: p = 0.31; Mann-Whitney U Test: p = 0.63].

CONCLUSION

These early findings suggested critical value of absolute and relative pOSM to characterize the inflammatory burden of ARDS patients and the outcome of their V-V ECMO support.

Diagnosis of septic shock by serum measurement of human neutrophil lipocalin by a rapid homogeneous assay

BACKGROUND

Human neutrophil lipocalin (HNL) is a marker of neutrophil activation and has a high efficacy in diagnosing bacterial infections. In this study, we applied the AlphaLISA technique to measure the serum level of HNL, evaluate HNL's efficacy in diagnosing septic shock, and identify any association between HNL level and septic patients' prognosis.

METHODS

We collected 146 serum samples from the Fifth Medical Center of Chinese PLA General Hospital. HNL was measured by AlphaLISA and results were compared with commercial ELISA kits. We studied 78 patients admitted to the ICU with sepsis and data on their clinical and physiological characteristics were recorded. Blood levels of HNL, procalcitonin (PCT), high-sensitivity C-reactive protein (hs-CRP), and lactate were measured. A receiver operating characteristic (ROC) curve was used to evaluate the performance of each marker.

RESULTS

The AlphaLISA assay for serum HNL had a detection range from 1.5 ng/mL to 1000 ng/mL, with a detection limit of 1 ng/mL and a detection time of approximately 25 min. The AlphaLISA assay's results were in high agreement with ELISA results (R2 = 0.9413). HNL levels were analyzed in sepsis patients, and HNL was significantly higher in sepsis patients with shock compared to sepsis patients without shock (median 356.47 ng/mL vs 158.93 ng/mL, P < 0.0001) and in the 28-day non-survivor group compared to the 28-day survivor group (median 331.83 ng/mL vs 175.17 ng/mL, P < 0.0001). ROC curve analysis was performed for the biomarkers. In differentiating the diagnosis of septic shock from sepsis patients, HNL was the most effective marker (AUC = 0.857), followed by PCT (AUC = 0.754) and hs-CRP (AUC = 0.627). In predicting the prognosis of septic patients, lactate had the best effect (AUC = 0.805), followed by HNL (AUC = 0.784), PCT (AUC = 0.721), and hs-CRP (AUC = 0.583).

CONCLUSIONS

As an assessment tool, we found that our AlphaLISA had good consistency with an ELISA and had several other advantages, including requiring a shorter processing time and detecting a wider range of serum HNL concentrations. Monitoring serum HNL levels of patients admitted to the ICU might be useful in distinguishing sepsis patients who have septic shock from other sepsis patients, indicating its value in the prediction of sepsis patient prognosis.

Metformin-Associated Lactic Acidosis in Individuals Without Chronic Kidney Disease on Therapeutic Dose: A Case Report

Metformin-associated lactic acidosis (MALA) is a severe side effect of metformin treatment. We encountered an exceedingly rare case of MALA in a patient taking metformin at recommended doses who had no risk factors except for advanced age. A 77-year-old male with a diagnosis of lactic acidosis was referred to our facility. He was taking 250 mg/day of metformin for diabetes. Although he had no pre-existing chronic kidney disease, he developed acute kidney injury upon admission, leading to the diagnosis of MALA based on the test results and history of metformin use. His lactic acidosis improved without extracorporeal treatment through metformin discontinuation and proper circulatory management. When encountering patients with unexplained lactic acidosis, it is important to consider MALA as part of the differential diagnosis and to confirm the patient's medication history. Specifically, when metformin use is identified, attention should be directed toward the potential for MALA.

Association between prehospital lactate categories with short- and long-term mortality: a prospective, observational multicenter study

BACKGROUND

Lactate is an already recognized biomarker for short-term mortality in emergency medical services (EMS). However, how different levels of lactate are associated with short-, mid- and long-term outcomes should be unveiled.

AIM

To determine how different categories of hyperlactatemia are associated with mortality. We also aim to clinically characterize hyperlactatemia groups.

DESIGN

A multicenter, prospective, observational study performed between January 2019 and February 2022, considering 48 basic life support units and 5 advanced life support units referring to 4 tertiary care hospitals (Spain). Patients were recruited from phone requests for emergency assistance in adults, evacuated to emergency departments. The primary outcome was in-hospital mortality from any cause within the first to the 365-day period following EMS attendance. The main measures were demographical and biochemical variables, prehospital advanced life support techniques used and patient condition categorized in 24 diseases.

METHODS

Univariate and Cox regression analysis.

RESULTS

A total of 5072 participants fulfilled inclusion criteria. Group #1 (non-hyperlactatemia) was composed of 2389 subjects (47.1%), Group #2 (mild hyperlactatemia) of 1834 (36.1%), Group #3 (hyperlactatemia) of 333 (6.6%) and, finally, Group #4 (severe hyperlactatemia) of 516 (10.2%). The 1-day mortality was 0.2%, 1.1%, 9% and 22.3% in the four lactate groups, respectively. Long-term mortality (365 days) was 10.2%, 22.7%, 38.7% and 46.7% in the four lactate groups, respectively. Differences between patients' conditions of lactatemia groups were also found.

CONCLUSIONS

Our results demonstrated that prehospital lactate categories were associated with short- and long-term outcomes in a different manner. These results will allow EMS to establish different risk states according to the prehospital lactate categories.

Lactate as a Screening Tool for Critical Illness in a Pediatric Emergency Department

OBJECTIVES

Lactate has in some pediatric emergency departments (PEDs) gained acceptance as a screening tool for critical illness, with cut-off values of 2.0 to 2.5 mmol/L. We aimed to investigate if lactate could predict the need of acute resuscitation in patients in a PED.

PATIENTS AND METHODS

This retrospective observational cohort study included patients aged 0 to 17 years admitted to the PED at Copenhagen University Hospital in Denmark from January 1, 2019 to January 1, 2021. Patients were included if they had lactate measured as part of their routine blood sampling because of acute PED evaluation. Area under the receiver operating characteristic (ROC) curve (AUC) was calculated to assess the ability of lactate to predict the need of acute resuscitation. In patients without need of acute resuscitation, we calculated the lactate upper limit as the 95th percentile, and significant predictors were included in a multiple linear regression model.

RESULTS

A total of 1355 children were included. Fourteen (1%) children with a need of acute resuscitation had a median lactate of 1.7 mmol/L (interquartile range, 1.4-2.3) versus 1.6 mmol/L (interquartile range, 1.3-2.1) in children without need of resuscitation ( P > 0.05). The AUC for lactate to predict acute resuscitation was 0.56 (95% confidence interval, 0.54-0.59). In children without need of acute resuscitation, the 95th percentile of lactate was 3.2 mmol/L, and 392 (29.8%) had lactate greater than 2.0 mmol/L. Increasing age and venous sampling were associated with lower lactate. Lactate was not associated with sex, pediatric early warning score, or duration of hospital admission. The 95th percentile of lactate after inhaled beta-2-agonists was 5.0 mmol/L.

CONCLUSIONS

In children evaluated in a PED, lactate achieved a low AUC, suggesting a poor ability of predicting acute resuscitation. In children without need of acute resuscitation, the 95th percentile for lactate was 3.2 mmol/L, higher than the generally accepted cut-off values. This is important to recognize to avoid concern in otherwise clinically stable children. Our data did not support the use of lactate as a screening tool for early recognition of critical illness in a PED.

A hypoxia- and lactate metabolism-related gene signature to predict prognosis of sepsis: discovery and validation in independent cohorts

BACKGROUND

High throughput gene expression profiling is a valuable tool in providing insight into the molecular mechanism of human diseases. Hypoxia- and lactate metabolism-related genes (HLMRGs) are fundamentally dysregulated in sepsis and have great predictive potential. Therefore, we attempted to build an HLMRG signature to predict the prognosis of patients with sepsis.

METHODS

Three publicly available transcriptomic profiles of peripheral blood mononuclear cells from patients with sepsis (GSE65682, E-MTAB-4421 and E-MTAB-4451, total n = 850) were included in this study. An HLMRG signature was created by employing Cox regression and least absolute shrinkage and selection operator estimation. The CIBERSORT method was used to analyze the abundances of 22 immune cell subtypes based on transcriptomic data. Metascape was used to investigate pathways related to the HLMRG signature.

RESULTS

We developed a prognostic signature based on five HLMRGs (ERO1L, SIAH2, TGFA, TGFBI, and THBS1). This classifier successfully discriminated patients with disparate 28-day mortality in the discovery cohort (GSE65682, n = 479), and consistent results were observed in the validation cohort (E-MTAB-4421 plus E-MTAB-4451, n = 371). Estimation of immune infiltration revealed significant associations between the risk score and a subset of immune cells. Enrichment analysis revealed that pathways related to antimicrobial immune responses, leukocyte activation, and cell adhesion and migration were significantly associated with the HLMRG signature.

CONCLUSIONS

Identification of a prognostic signature suggests the critical role of hypoxia and lactate metabolism in the pathophysiology of sepsis. The HLMRG signature can be used as an efficient tool for the risk stratification of patients with sepsis.

A Review of Bicarbonate Use in Common Clinical Scenarios

BACKGROUND

The use of sodium bicarbonate to treat metabolic acidosis is intuitive, yet data suggest that not all patients benefit from this therapy.

OBJECTIVE

In this narrative review, we describe the physiology behind commonly encountered nontoxicologic causes of metabolic acidosis, highlight potential harm from the indiscriminate administration of sodium bicarbonate in certain scenarios, and provide evidence-based recommendations to assist emergency physicians in the rational use of sodium bicarbonate.

DISCUSSION

Sodium bicarbonate can be administered as a hypertonic push, as a resuscitation fluid, or as an infusion. Lactic acidosis and cardiac arrest are two common scenarios where there is limited benefit to routine use of sodium bicarbonate, although certain circumstances, such as patients with concomitant acute kidney injury and lactic acidosis may benefit from sodium bicarbonate. Patients with cardiac arrest secondary to sodium channel blockade or hyperkalemia also benefit from sodium bicarbonate therapy. Recent data suggest that the use of sodium bicarbonate in diabetic ketoacidosis does not confer improved patient outcomes and may cause harm in pediatric patients. Available evidence suggests that alkalinization of urine in rhabdomyolysis does not improve patient-centered outcomes. Finally, patients with a nongap acidosis benefit from sodium bicarbonate supplementation.

CONCLUSIONS

Empiric use of sodium bicarbonate in patients with nontoxicologic causes of metabolic acidosis is not warranted and likely does not improve patient-centered outcomes, except in select scenarios. Emergency physicians should reserve use of this medication to conditions with clear benefit to patients.

The diagnostic accuracy of an initial point-of-care lactate at the emergency department as a predictor of in-hospital mortality among adult patients with sepsis and septic shock

Background

In patients with sepsis, elevated lactate has been shown to be a strong predictor of in-hospital mortality. However, the optimal cutoff for rapidly stratifying patients presenting to the emergency department at risk for increased in-hospital mortality has not been well defined. This study aimed to establish the optimal point-of-care (POC) lactate cutoff that best predicted in-hospital mortality in adult patients presenting to the emergency department.

Methods

This was a retrospective study. All adult patients who presented to the emergency department at the Aga Khan University Hospital, Nairobi, between 1 January 2018 and 31 August 2020 with suspected sepsis or septic shock and were admitted to the hospital were included in the study. Initial POC lactate results (GEM 3500^® blood gas analyzer) and demographic and outcome data were collected. A receiver operating characteristic (ROC) curve for initial POC lactate values was plotted to determine the area under the curve (AUC). An optimal initial lactate cutoff was then determined using the Youden Index. Kaplan-Meier curves were used to determine the hazard ratio (HR) for the identified lactate cutoff.

Results

A total of 123 patients were included in the study. They had a median age of 61 years [interquartile range (IQR) 41.0-77.0]. Initial lactate independently predicted in-hospital mortality [adjusted odds ratio (OR) 1.41 95% confidence interval (CI 1.06, 1.87) p = 0.018]. Initial lactate was found to have an area under the curve (AUC) of 0.752 (95% CI, 0.643 to 0.86). Additionally, a cutoff of 3.5 mmol/L was found to best predict in-hospital mortality (sensitivity 66.7%, specificity 71.4%, PPV 70%, NPV 68.2%). Mortality was 42.1% (16/38) in patients with an initial lactate of ≥ 3.5 mmol/L and 12.7% (8/63) in patients with an initial lactate of <3.5 mmol/L (HR, 3.388; 95% CI, 1.432-8.018; p < 0.005).

Discussion

An initial POC lactate of ≥ 3.5 mmol/L best predicted in-hospital mortality in patients presenting with suspected sepsis and septic shock to the emergency department. A review of the sepsis and septic shock protocols will help in the early identification and management of these patients to reduce their in-hospital mortality.

Comparison between Capillary and Serum Lactate Levels in Predicting Short-Term Mortality of Septic Patients at the Emergency Department

Sepsis is a time-dependent and life-threating condition related to macro- and micro-circulatory impairment leading to anaerobic metabolism and lactate increase. We assessed the prognostic accuracy of capillary lactates (CLs) vs. serum ones (SLs) on 48-h and 7-day mortality in patients with suspected sepsis. This observational, prospective, single-centre study was conducted between October 2021 and May 2022. Inclusion criteria were: (i) suspect of infection; (ii) qSOFA ≥ 2; (iii) age ≥ 18 years; (iv) signed informed consent. CLs were assessed with LactateProTM2^®. 203 patients were included: 19 (9.3%) died within 48 h from admission to the Emergency Department, while 28 (13.8%) within 7 days. Patients deceased within 48 h (vs. survived) had higher CLs (19.3 vs. 5 mmol/L, p < 0.001) and SLs (6.5 vs. 1.1 mmol/L, p = 0.001). The best CLs predictive cut-off for 48-h mortality was 16.8 mmol/L (72.22% sensitivity, 94.02% specificity). Patients within 7 days had higher CLs (11.5 vs. 5 mmol/L, p = 0.020) than SLs (2.75 vs. 1.1 mmol/L, p < 0.001). The multivariate analysis confirmed CLs and SLs as independent predictors of 48-h and 7-day mortality. CLs can be a reliable tool for their inexpensiveness, rapidity and reliability in identifying septic patients at high risk of short-term mortality.

Remote preconditioning combined with nebulized budesonide alleviate lipopolysaccharide induced acute lung injury via regulating HO-1 and NF-κB in rats

BACKGROUND

Acute lung injury (ALI) may result in severe systemic inflammation and is life-threatening. Remote inflammatory preconditioning (RIPC) has been confirmed to have an endogenous protective effect against ALI. Budesonide (BS) is a potent corticosteroid typically administered through nebulization that reduces inflammation in the lungs. We speculate that the combined use of RIPC and nebulized BS has a stronger protective effect on ALI.

METHODS

48 Sprague-Dawley male rats were used for the experiments. Animals were divided evenly and randomly into three groups, control (NS injection), LPS (LPS injection), and RIPC (LPS injection with RIPC). Each group was then divided into two subgroups with inhalation of nebulized normal saline (NS) or BS. Prior to injection of LPS, RIPC was performed by tying and untying the right hind limb for three cycles of five minutes each. Following LPS injection, animals in each subgroup were placed in a same cage for nebulized inhalation. Animals were sacrificed 6 hours after LPS injection. Histological evaluation of ALI and lung wet-to-dry weight ratio were measured. Serum lactate acid, inflammatory cytokines, oxidative stress indicators were detected. The expression of HO-1, NF-κB p65 and p-p65 was measured by western blotting.

RESULTS

RIPC combined with nebulized BS significantly attenuated the LPS-induced ALI in rats. Reduction of MDA, increasing of SOD activity were found significantly improved by the joint strategy. TNF- and IL-1β rise brought on by LPS was reduced, but IL-10 production dramatically enhanced when compared to the LPS group. The expression of HO-1 was significantly increased by RIPC combined with nebulized BS while the expression of NF-κB p65 and p-p65 was decreased when compared with the LPS group.

CONCLUSION

RIPC combined with nebulized budesonide is protective for ALI induced by LPS in rats.

Does lactate enhance the prognostic accuracy of the quick Sequential Organ Failure Assessment for adult patients with sepsis? A systematic review

OBJECTIVES

To investigate whether adding lactate to the quick Sequential (sepsis-related) Organ Failure Assessment (qSOFA) improves the prediction of mortality in adult hospital patients, compared with qSOFA alone.

DESIGN

Systematic review in accordance with Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies guidelines.

DATA SOURCES

Embase, Medline, PubMed, SCOPUS, Web of Science, CINAHL and Open Grey databases were searched in November 2020.

ELIGIBILITY CRITERIA

Original research studies published after 2016 comparing qSOFA in combination with lactate (LqSOFA) with qSOFA alone in adult patients with sepsis in hospital. The language was restricted to English.

DATA EXTRACTION AND SYNTHESIS

Title and abstract screening, full-text screening, data extraction and quality assessment (using Quality Assessment of Diagnostic Accuracy Studies-2) were conducted independently by two reviewers. Extracted data were collected into tables and diagnostic test accuracy was compared between the two tests.

RESULTS

We identified 1621 studies, of which 11 met our inclusion criteria. Overall, there was a low risk of bias across all studies. The area under the receiver operating characteristic (AUROC) curve for qSOFA was improved by the addition of lactate in 9 of the 10 studies reporting it. Sensitivity was increased in three of seven studies that reported it. Specificity was increased in four of seven studies that reported it. Of the six studies set exclusively within the emergency department, five published AUROCs, all of which reported an increase following the addition of lactate. Sensitivity and specificity results varied throughout the included studies. Due to insufficient data and heterogeneity of studies, a meta-analysis was not performed.

CONCLUSIONS

LqSOFA is an effective tool for identifying mortality risk both in adult inpatients with sepsis and those in the emergency department. LqSOFA increases AUROC over qSOFA alone, particularly within the emergency department. However, further original research is required to provide a stronger base of evidence in lactate measurement timing, as well as prospective trials to strengthen evidence and reduce bias.

PROSPERO REGISTRATION NUMBER

CRD42020207648.

Analysis of the Predictive Effect of Lactic Acid Combined with Cardiac Troponin T and 5-Hydroxytryptophan on the Severity of Sepsis in ICU Patients and Its Correlation with Prognosis

In order to explore the effective markers of presepsis in the prediction of clinical disease and disease severity, the predictive effect of lactic acid (Lac) combined with cardiac troponin T (cTnT) and 5-hydroxytryptophan (5-HT) on the severity of sepsis in intensive care unit (ICU) patients and its correlation with prognosis is investigated. A total of 85 sepsis patients admitted to the ICU of our hospital from January 2020 to June 2021 are selected to establish the ICU sepsis group, and 72 health examination patients who received physical examination in our hospital during the same period are included in the healthy control group. The experimental results demonstrate that combined detection mode of serum Lac, cTnT, and 5-HT indicators has a high predictive value for the condition of patients with ICU sepsis and those indicators are closely correlated with the prognosis of patients. It suggests that the follow-up clinical monitoring of serum Lac, cTnT, and 5-HT indicators for patients with ICU sepsis can evaluate their condition and improve and optimize the clinical diagnosis and treatment plan effectively.

Prevalence and clinical significance of point of care elevated lactate at emergency admission in older patients: a prospective study

OBJECTIVE

Patients who are over 65 years old represent up to 24% of emergency department (ED) admissions. They are at increased risk of under-triage due to impaired physiological responses. The primary objective of this study was to assess the prevalence of elevated lactate by point of care testing (POCT) in this population. The secondary objective was to assess the additional value of lactate level in predicting an early poor outcome, as compared to and combined with common clinical scores and triage scales.

METHODS

This monocentric prospective study recruited ED patients who were over 65 years old between July 19th 2019 and June 17th 2020. Patients consulting for seizures or needing immediate assessment were excluded. POCT lactates were considered elevated if ≥ 2.5 mmol/L. A poor outcome was defined based on certain complications or therapeutic decisions.

RESULTS

In total, 602 patients were included; 163 (27.1%) had elevated lactate and 44 (7.3%) had a poor outcome. There was no association between poor outcome and lactate level. Modified Early Warning Score (MEWS) was significantly associated with poor outcome, alongside National Early Warning Score (NEWS). Logistic regression also associated lactate level combined with MEWS and poor outcome.

CONCLUSION

The prevalence of elevated lactate was 27.1%. Lactate level alone or combined with different triage scales or clinical scores such as MEWS, NEWS and qSOFA was not associated with prediction of a poor outcome. MEWS alone performed best in predicting poor outcome. The usefulness of POCT lactate measurement at triage is questionable in the population of 65 and above.

Development of a Nomogram Model to Predict in-Hospital Survival in Patients with Multiple Trauma

Background

Herein, we purposed to establish a nomogram model capable of assessing the probability of in-hospital survival in patients with multiple trauma.

Methods

Our retrospective study is associated with 286 multiple trauma patients with 21 variables from 2017 to 2021 in The Second Affiliated Hospital, Hengyang Medical School, University of South China. We performed the univariate and multivariate logistic regression analyses for investigating the risk factors of multiple trauma. Further, we constructed a novel nomogram model, and this nomogram was evaluated by a calibration plot. Based on the multivariate analysis or the nomogram prediction model, we calculated the risk score of each patient for multiple trauma. Moreover, we compared the survival probability between the high-risk score and low-risk score groups. Finally, we assessed the discrimination of the risk score by using the C-index and the time-dependent receiver operating characteristics (ROC) curve.

Results

Multivariate regression analysis revealed that the age and ISS scores were the independent risk factors, while the GCS score had protective effects on in-hospital survival. The high C-index and area under the curve (AUC) of the ROC curve confirmed reasonable discrimination for the multivariate analysis and the nomogram prediction model. Further, the calibration plot indicated reasonable accuracy of the nomogram predicting 30-day and 60-day survival probabilities.

Conclusion

The nomogram model established here has good predictive efficacy for in-hospital survival of patients with multiple injuries.

Sepsis triggered oxidative stress-inflammatory axis: the pathobiology of reprogramming in the normal sleep-wake cycle

In individuals with sepsis-related neurodegenerative illness, sleep and circadian rhythm disturbance are common. The alteration in genomic expression linked with the immune-directed oxidative stress-inflammatory axis is thought to cause these individuals' abnormal sleep. On the other hand, sleep is linked to normal brain activity through common neurotransmitter systems and regulatory mechanisms. Ailments (ranging from cognitive to metabolic abnormalities) are seldom related to aberrant sleep that is made worse by sleep disturbance, which throws off the body's sleep-wake cycle. PubMed/Springer link /Public library of science/ScienceDirect/ Mendeley/Medline and Google Scholar were used to find possibly relevant studies. For the literature search, many keywords were considered, both individually and in combination. 'Sepsis,' 'Epidemiology of sepsis,' 'Sepsis-related hyper inflammation,' 'Relationship of sepsis-associated clock gene expression and relationship of inflammation with the reprogramming of genetic alterations' were some of the key terms utilized in the literature search. Our main objective is to understand better how traumatic infections during sepsis affect CNS processes, particularly sleep, by investigating the pathobiology of circadian reprogramming associated with immune-directed oxidative stress-inflammatory pathway responsive gene expression and sleep-wake behaviour in this study.

A Novel Strategy for Predicting 72-h Mortality After Admission in Patients With Polytrauma: A Study on the Development and Validation of a Web-Based Calculator

Background

Early and accessible screening of patients with polytrauma at a high risk of hospital death is essential. The purpose of this research was to seek an accurate and convenient solution to predict deaths occurring within 72 h after admission of these patients.

Methods

A secondary analysis was conducted on 3,075 patients with polytrauma from the Dryad database. We imputed missing values in eligible individuals with the k-nearest neighbor algorithm and then randomly stratified them into the training group (n = 2,461) and the validation group (n = 614) based on a proportion of 8:2. The restricted cubic spline, univariate, backward stepwise, and multivariate logistic regression methods were employed to determine the suitable predictors. Calibration and receiver operating characteristic (ROC) curves were applied to assess the calibration and discrimination of the obtained model. The decision curve analysis was then chosen as the measure to examine the clinical usage.

Results

Age, the Glasgow Coma Scale score, the Injury Severity Score, base excess, and the initial lactate level were inferred as independent prognostic factors related to mortality. These factors were then integrated and applied to construct a model. The performance of calibration plots, ROC curves, and decision curve analysis indicated that the model had satisfactory predictive power for 72-h mortality after admission of patients with polytrauma. Moreover, we developed a nomogram for visualization and a web-based calculator for convenient application (https://songandwen.shinyapps.io/DynNomapp/).

Conclusions

A convenient web-based calculator was constructed to robustly estimate the risk of death in patients with polytrauma within 72 h after admission, which may aid in further rationalization of clinical decision-making and accurate individual treatment.

A 2-year retrospective analysis of the prognostic value of MqSOFA compared to lactate, NEWS and qSOFA in patients with sepsis

Purpose

Sepsis is a life-threating organ dysfunction caused by a dysregulated host response to infection. Being a time-dependent condition, the present study aims to compare a recently established score, i.e., modified quick SOFA (MqSOFA), with other existing tools commonly applied to predict in-hospital mortality.

Methods

All cases of sepsis and septic shock consecutively observed at St. Anna University Hospital of Ferrara, Italy, from January 2017 to December 2018 were included in this study. Each patient was evaluated with MqSOFA, lactate assay, NEWS and qSOFA. Accurate statistical and logistic regression analyses were applied to our database.

Results

A total of 1001 consecutive patients with sepsis/septic shock were retrieved. Among them, 444 were excluded for incomplete details about vital parameters; thus, 556 patients were eligible for the study. Data analysis showed that MqSOFA, NEWS and lactate assay provided a better predictive ability than qSOFA in terms of in-hospital mortality (p < 0.001). Aetiology-based stratification in 5 subgroups demonstrated the superiority of NEWS vs. other tools in predicting fatal outcomes (p = 0.030 respiratory, p = 0.036 urinary, p = 0.044 abdominal, p = 0.047 miscellaneous and p = 0.041 for indeterminate causes). After Bonferroni’s correction, MqSOFA was superior to qSOFA over respiratory (p < 0.001) and urinary (p < 0.001) aetiologies. Age was an independent factor for negative outcomes (p < 0.001).

Conclusions

MqSOFA, NEWS and lactate assay better predicted in-hospital mortality compared to qSOFA. Since sepsis needs a time-dependent assessment, an easier and non-invasive score, i.e., MqSOFA, could be used to establish patients’ outcome in the emergency setting.

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.

Blood lactate concentrations during rest and exercise in people with Multiple Sclerosis: A systematic review and meta-analysis

BACKGROUND

Multiple Sclerosis (MS) is a chronic disorder which irreversibly damages axons within brain matter. Blood lactate concentration could be a biomarker of MS onset and progression, but no systematic review has yet sought to confirm or dispute the elevation and biomarker potential of blood lactate in people with MS (PwMS) or to consolidate understanding of lactate production during exercise in PwMS.

OBJECTIVE

To perform a systematic review and meta-analysis on blood lactate in PwMS during rest and exertion compared to Healthy Controls (HC) and following chronic exercise intervention.

METHODS

A systematic search of six electronic databases (PubMed, CINAHL, Science Direct, Cochrane Library, SPORTDiscus and PEDro) was performed on 10th April 2020. Mean, standard deviation and sample size for lactate measures at rest and during exercise were pooled to determine overall effect size using a random effects model.  The 20-point Appraisal tool for Cross-Sectional Studies was utilised to assess study quality and inherent risk of bias. To qualify for inclusion, studies had to include human adults (>18 years) with a confirmed clinical diagnosis of MS, be published in English, have undergone peer review, report absolute blood lactate values for data extraction, and if involving testing during/after exercise, to do so during bilateral exercise methods.

RESULTS

18 studies were qualitatively analysed and 15 studies quantitatively analysed. Outcome data was available for 1986 participants (n_MS = 1129). A total of 7 papers tested blood lactate during rest (Lactate_REST), 7 papers tested during sub-maximal intensity exercise (Lactate_SUB-MAX), and 8 papers tested during maximal intensity exercise (Lactate_MAX). Meta analyses showed elevated Lactate_REST and reduced Lactate_MAX in PwMS compared to HC, higher Lactate_MAX in lower EDSS-scoring PwMS compared to higher EDSS-scoring PwMS, and that Lactate_SUB-MAX decreases and Lactate_MAX increases in PwMS following a chronic exercise intervention. Qualitative analysis reported Lactate_REST to be reduced in PwMS following a chronic exercise intervention.

CONCLUSIONS

Lactate_REST is elevated in PwMS compared to HC. Lactate_MAX is lower in PwMS compared to HC and lower still in higher compared to lower EDSS-scoring groups of PwMS. Chronic exercise interventions have the potential to reduce Lacatate_SUB-MAX for a given power output and increase Lactate_MAX in PwMS compared to baseline values. Lactate_REST may be reduced in PwMS following a chronic exercise intervention but more research is required for confirmation. The results of this review were limited by small sample sizes and number of studies available for each testing condition, limited data available for potentially confounding/correlating factors (eg. VO₂ and power output) as well as heterogeneity of methodology adopted across studies, often due to lactate testing being a secondary outcome measure. PLS: Lactate levels in the blood are different during rest and at intense exercise levels in people with Multiple Sclerosis (MS) compared to healthy counterparts, with people with MS showing a smaller jump in lactate during intense exercise from a higher resting level. After exercising for at least 3 months, blood lactate levels during exercise may become more similar to the levels seen in people without Multiple Sclerosis, but more research is required to give a clearer picture of this. We can hopefully use blood lactate in future to measure the progression of MS in an individual as well as the effectiveness of their exercise programme.

Remote Inflammatory Preconditioning Alleviates Lipopolysaccharide-Induced Acute Lung Injury via Inhibition of Intrinsic Apoptosis in Rats

Background

Acute lung injury (ALI) always leads to severe inflammation. As inflammation and oxidative stress are the common pathological basis of endotoxin-induced inflammatory injury and ischemic reperfusion injury (IRI), we speculate that remote ischemic preconditioning (RIPC) can be protective for ALI when used as remote inflammatory preconditioning (RInPC).

Method

A total of 21 Sprague-Dawley rats were used for the animal experiments. Eighteen rats were equally and randomly divided into the control (NS injection), LPS (LPS injection), and RInPC groups. The RInPC was performed prior to the LPS injection via tourniquet blockage of blood flow to the right hind limb and adopted three cycles of 5 min tying followed by 5 min untying. Animals were sacrificed 24 hours later. There were 2 rats in the LPS group and 1 in the RInPC group who died before the end of the experiment. Supplementary experiments in the LPS and RInPC groups were conducted to ensure that 6 animals in each group reached the end of the experiment.

Results

In the present study, we demonstrated that the RInPC significantly attenuated the LPS-induced ALI in rats. Apoptotic cells were reduced significantly by the RInPC, with the simultaneous improvement of apoptosis-related proteins. Reduction of MPO and MDA and increasing of SOD activity were found significantly improved by the RInPC. Increasing of TNF-α, IL-1β, and IL-6 induced by the LPS was inhibited, while IL-10 was significantly increased by RInPC, compared to the LPS group.

Conclusion

RInPC could inhibit inflammation and attenuate oxidative stress, thereby reducing intrinsic apoptosis and providing lung protection in the LPS-induced ALI in rats.

Remote Inflammatory Preconditioning Alleviates Lipopolysaccharide-Induced Acute Lung Injury via Inhibition of Intrinsic Apoptosis in Rats

BACKGROUND

Acute lung injury (ALI) always leads to severe inflammation. As inflammation and oxidative stress are the common pathological basis of endotoxin-induced inflammatory injury and ischemic reperfusion injury (IRI), we speculate that remote ischemic preconditioning (RIPC) can be protective for ALI when used as remote inflammatory preconditioning (RInPC).

METHOD

A total of 21 Sprague-Dawley rats were used for the animal experiments. Eighteen rats were equally and randomly divided into the control (NS injection), LPS (LPS injection), and RInPC groups. The RInPC was performed prior to the LPS injection via tourniquet blockage of blood flow to the right hind limb and adopted three cycles of 5 min tying followed by 5 min untying. Animals were sacrificed 24 hours later. There were 2 rats in the LPS group and 1 in the RInPC group who died before the end of the experiment. Supplementary experiments in the LPS and RInPC groups were conducted to ensure that 6 animals in each group reached the end of the experiment.

RESULTS

In the present study, we demonstrated that the RInPC significantly attenuated the LPS-induced ALI in rats. Apoptotic cells were reduced significantly by the RInPC, with the simultaneous improvement of apoptosis-related proteins. Reduction of MPO and MDA and increasing of SOD activity were found significantly improved by the RInPC. Increasing of TNF-α, IL-1β, and IL-6 induced by the LPS was inhibited, while IL-10 was significantly increased by RInPC, compared to the LPS group.

CONCLUSION

RInPC could inhibit inflammation and attenuate oxidative stress, thereby reducing intrinsic apoptosis and providing lung protection in the LPS-induced ALI in rats.

„C-Probleme“ des nichttraumatologischen Schockraummanagements

Im Rahmen des nichttraumatologischen Schockraummanagements zur Versorgung kritisch kranker Patienten werden akute Störungen der Vitalfunktionen rasch detektiert und behandelt. Beim „primary survey“ (Erstversorgung) dient das etablierte ABCDE-Schema der strukturierten Untersuchung aller relevanten Vitalparameter. Akute Störungen werden hierbei unmittelbar detektiert und therapiert. „C-Probleme“ stellen den größten Anteil der ABCDE-Störungen bei nichttraumatologischen Schockraumpatienten dar und zeichnen sich durch eine hämodynamische Instabilität infolge hypovolämischer, obstruktiver, distributiver oder kardiogener Schockformen aus. Abhängig von den lokalen Versorgungsstrukturen umfasst die nichttraumatologische Schockraumversorgung hierbei auch die Stabilisierung von Patienten mit akutem Koronarsyndrom oder nach prähospitaler Reanimation (Cardiac Arrest Center).

Effect of Dietary Supplementation With Mixed Organic Acids on Immune Function, Antioxidative Characteristics, Digestive Enzymes Activity, and Intestinal Health in Broiler Chickens

The purpose of this study was to explore the effect of dietary supplementation with mixed organic acids on intestinal health, enzyme activity, and antioxidative characteristics in broilers. A total of 192 1-day-old chicks were evenly allocated to three experimental groups with eight replicates, a basal diet with 0 (Control), 3,000 mg/kg (LMOA), 6,000 mg/kg (HMOA) mixed organic acid. The tissue and serum samples were gathered on 21 and 42 d of the experiment. An increased (P < 0.05) concentration of IgA, D-lactate (D-LA), and interleukin-10 (IL-10) in the serum of broilers diets with HMOA was observed. The levels of total antioxidant capacity (T-AOC) and catalase activity (CAT) in serum were enhanced (P < 0.05) with dietary and mixed organic acid, respectively, and increased (P < 0.05) content of superoxide dismutase (SOD) and CAT in the duodenum of broilers diets with LMOA was noticed. Also, LMOA decreased (P < 0.05) the pH value of the duodenum and enhanced (P < 0.05) the amylase activity of the pancreas, the tight junction protein (mainly Claudin-1, Claudin-2, and ZO-1) in the duodenum of broilers fed with mixed organic acid were promoted (P < 0.05), and the LMOA group performed better in the small intestine. In cecum microbiota, LMOA and HMOA modulated the structure of microbiota and mainly reduced the relative abundance of Escherichia coli. In brief, dietary supplemented mixed organic acid improved the health status of broilers by promoting the immune function, enhancing the antioxidative characteristics and tight junction proteins expression as well as cecum microbiota. However, LMOA groups may be a better fit considering the comprehensive effects of experiments and economic costs.

Hyperlactatemia associated with diabetic ketoacidosis in pediatric intensive care unit

BACKGROUND

Children with diabetic ketoacidosis often have elevated lactate. In this study, we investigated the clinical variables associated with hyperlactatemia in children with diabetic ketoacidosis.

METHODS

We designed a single-center retrospective descriptive study of children with diabetic ketoacidosis in a pediatric intensive care unit.

RESULTS

Of the 107 patients with diabetic ketoacidosis included in the analysis, 61 developed hyperlactatemia. Multivariate logistic regression analysis showed that heart rate (p = 0.003),diastolic blood pressure (p = 0.001) and stage of severity (p = 0.042) were independently associated with the development of hyperlactatemia in diabetic ketoacidosis. We found that lactate level was not significantly associated with length of hospital stay (p = 0.115) or the length of time to diabetic ketoacidosis resolution (p = 0.143).

CONCLUSIONS

Children with diabetic ketoacidosis presenting with severer stage, elevated heart rate and higher diastolic blood pressure may be prone to hyperlactatemia. Hyperlactatemia was not associated with length of time to DKA resolution and length of hospital stay.

A BERIBERI UNHEALTHY LATTE: ENCEPHALOPATHY AND SHOCK FROM SEVERE NUTRITIONAL DEFICIENCY

BACKGROUND

Thiamine deficiency is an uncommon cause of severe illness in the United States that can lead to significant morbidity because of high-output cardiac failure, peripheral neuropathy, and permanent neurologic impairment. We report the case of a middle-aged woman with extreme malnutrition caused by complications of Roux-en-Y gastric bypass (RYGB) surgery who presented with signs and symptoms of severe thiamine deficiency and septic shock.

CASE REPORT

A 43-year-old woman who had undergone RYGB surgery and who had multiple complications presented to the emergency department with agitation, confusion, and lethargy. The physical examination revealed an obtunded woman appearing much older than her reported age with significant peripheral edema. She was hypoxemic, hypotensive, and febrile. The initial laboratory analysis revealed a serum lactate level above the measurable limit, a normal thyroid-stimulating hormone, and elevated levels of troponin and brain natriuretic peptide. A transthoracic echocardiogram showed high-output heart failure. The patient's family later revealed that for the past year her diet had consisted almost exclusively of frozen blended lattes. High doses of thiamine and folate were started. Her shock, hyperlactatemia, and respiratory failure resolved by hospital day 3 and her encephalopathy resolved soon thereafter. Why Should an Emergency Physician be Aware of This?: Thiamine deficiency is a rare but reversible cause of shock, heart failure, and encephalopathy. Identifying patients who are at risk for severe nutritional deficiencies may aid in more rapid treatment with relatively benign medications with little downside, in this case high-dose vitamin B₁, and ultimately improve patient-oriented outcomes such as mortality, morbidity, and hospital length of stay.

Effect of tourniquet time on whole blood point-of-care lactate concentration: A healthy human volunteer study

OBJECTIVE

Lactate is frequently utilised in clinical practice. Some have concerns that tourniquet application for venous blood collection may falsely elevate venous lactate. The objective of the present study was to determine the effect of tourniquet time on varying venous lactate concentrations.

METHODS

This is a healthy volunteer study, in which subjects were their own controls. A cannula was inserted into each arm, with a tourniquet remaining on one. Subjects were allocated to one of three groups; rest (no activity), exercise (maximal exertion to elevate lactate concentrations) with immediate tourniquet application or exercise with delayed (5-min post-exercise) tourniquet application. In all blood was drawn simultaneously from both cannulas at 0, 2.5, 5, 10 and 15-min post-tourniquet application and analysed for lactate on a point-of-care device. The primary outcome was a clinically significant difference (>1 mmol/L) in tourniquet versus non-tourniquet arm lactate concentration.

RESULTS

There were 10 subjects per group; the exercise groups achieved a mean maximum lactate concentration of 10.4 mmol/L (standard deviation [SD] 3.6) (exercise with immediate tourniquet application group) and 8.9 mmol/L (SD 2.5) (exercise with delayed tourniquet application group). There was no clinically significant increase in lactate concentration in the tourniquet compared to non-tourniquet arm in all groups, across all tourniquet application times, and over a range of lactate concentrations. In the rest group after 15-min of tourniquet application the mean lactate concentration of the tourniquet versus non-tourniquet arm was 0.91 mmol/L (SD 0.55) versus 0.89 mmol/L (SD 0.46) (P = 0.99), respectively.

CONCLUSION

In the present study tourniquet application for blood collection did not significantly increase lactate concentration. Hence, clinically a raised venous lactate concentration should not be attributed to prolonged tourniquet application.

Hypernatremia and moderate-to-severe hyponatremia are independent predictors of mortality in septic patients at emergency department presentation: A sub-group analysis of the need-speed trial

STUDY OBJECTIVE

Early risk stratification of septic patients presenting to the emergency department (ED) is challenging. The aim of the study was to evaluate the prognostic role of plasmatic sodium level (_PNa⁺) derangements at ED presentation in septic patients.

METHODS

According to _PNa⁺ at ED presentation patients were divided in eunatremic (136-145 mEq/L), hypernatremic (>145 mEq/L) and hyponatremic (<136 mEq/L). Hyponatremic patients were subsequently divided in mild (130-135 mEq/L), moderate (125-129 mEq/L) and severe (<125 mEq/L). 7 and 30-day mortality was evaluated according to _PNa⁺ derangements and the degree of hyponatremia. The same analysis was then performed only in respiratory tract infection-related (RTI-r) sepsis patients.

RESULTS

879 septic patients were included in this analysis, 40.3% had hyponatremia, 5.7% hypernatremia. Hypernatremia showed higher mortality rates at both endpoints compared to eunatremia and hyponatremia (p<0.0001 for both). Eunatremia and mild hyponatremia were compared vs. moderate-to-severe hyponatremia showing a significant difference in terms of 7 and 30-day survival (p = 0.004 and p = 0.007, respectively). The Cox proportional model identified as independent predictors of 7 and 30-day mortality moderate-to-severe hyponatremia (HR 4.89[2.38-10.03] and 1.79[1.07-3.01], respectively) and hypernatremia (HR 3.52[1.58-7.82] and 2.14[1.17-3.92], respectively). The same analysis was performed in patients with respiratory tract infection-related sepsis (n = 549), with similar results.

CONCLUSION

Both hypernatremia and moderate-to-severe hyponatremia at ED presentation independently predict mortality in septic patients, allowing early risk stratification and suggesting more aggressive therapeutic strategies.

Clinical Utility of Delta Lactate for Predicting Early In-Hospital Mortality in Adult Patients: A Prospective, Multicentric, Cohort Study

One of the challenges in the emergency department (ED) is the early identification of patients with a higher risk of clinical deterioration. The objective is to evaluate the prognostic capacity of ΔLA (correlation between prehospital lactate (pLA) and hospital lactate (hLA)) with respect to in-hospital two day mortality. We conducted a pragmatic, multicentric, prospective and blinded-endpoint study in adults who consecutively attended and were transported in advanced life support with high priority from the scene to the ED. The corresponding area under the receiver operating characteristics curve (AUROC) was obtained for each of the outcomes. In total, 1341 cases met the inclusion criteria. The median age was 71 years (interquartile range: 54–83 years), with 38.9% (521 cases) females. The total 2 day mortality included 106 patients (7.9%). The prognostic precision for the 2 day mortality of pLA and hLA was good, with an AUROC of 0.800 (95% CI: 0.74–0.85; p < 0.001) and 0.819 (95% CI: 0.76–0.86; p < 0.001), respectively. Of all patients, 31.5% (422 cases) had an ΔLA with a decrease of <10%, of which a total of 66 patients (15.6%) died. A lactate clearance ≥ 10% is associated with a lower risk of death in the ED, and this value could potentially be used as a guide to determine if a severely injured patient is improving in response to the established treatment.

Pulmonary pyruvate metabolism as an index of inflammation and injury in a rat model of acute respiratory distress syndrome

Increased pulmonary lactate production is correlated with severity of lung injury and outcome in acute respiratory distress syndrome (ARDS) patients. This study was conducted to investigate the relative contributions of inflammation and hypoxia to the lung's metabolic shift to glycolysis in an experimental animal model of ARDS using hyperpolarized (HP) ¹³ C MRI. Fifty-three intubated and mechanically ventilated male rats were imaged using HP ¹³ C MRI before, and 1, 2.5 and 4 hours after saline (sham) or hydrochloric acid (HCl; 0.5 ml/kg) instillation in the trachea, followed by protective and nonprotective mechanical ventilation (HCl-PEEP and HCl-ZEEP) or the start of moderate or severe hypoxia (Hyp90 and Hyp75 groups). Pulmonary and cardiac HP lactate-to-pyruvate ratios were compared among groups for different time points. Postmortem histology and immunofluorescence were used to assess lung injury severity and quantify the expression of innate inflammatory markers and local tissue hypoxia. HP pulmonary lactate-to-pyruvate ratio progressively increased in rats with lung injury and moderate hypoxia (HCl-ZEEP), with no significant change in pulmonary lactate-to-pyruvate ratio in noninjured but moderately hypoxic rats (Hyp90). Pulmonary lactate-to-pyruvate ratio was elevated in otherwise healthy lung tissue only in severe systemic hypoxia (Hyp75 group). ex vivo histological and immunopathological assessment further confirmed the link between elevated glycolysis and the recruitment into and presence of activated neutrophils in injured lungs. HP lactate-to-pyruvate ratio is elevated in injured lungs predominantly as a result of increased glycolysis in activated inflammatory cells, but can also increase due to severe inflammation-induced hypoxia.

Updates in Sepsis Resuscitation

Sepsis care has evolved significantly since the initial early goal-directed therapy (EGDT) trials. Early fluid resuscitation, source control, and antibiotic therapy remain cornerstones of care but overall understanding is more nuanced, particularly regarding fluid selection, vasopressors, and inotropic support. Timely nutrition therapy and ventilatory support tend to receive less attention but also are important. Recent research has explored immunomodulation, β-blockade, and vitamin supplementation. A renewed emphasis on early, aggressive resuscitation reaffirms the importance of emergency medicine providers knowledgeable and skilled in sepsis management.

Age-adjusted and Expanded Lactate Thresholds as Predictors of All-Cause Mortality in the Emergency Department

INTRODUCTION

While numerous studies have found emergency department (ED) lactate levels to be associated with increased in-hospital mortality, little information is available on the role age plays in this association. This study investigates whether age is a necessary variable to consider when using lactate levels as a marker of prognosis and a guide for management decisions in the ED.

METHODS

This was a retrospective cohort study in an urban, tertiary-care teaching hospital. A total of 13,506 lactate levels were obtained over a 4.5-year period. All adult patients who had a lactate level obtained by the treating provider in the ED were screened for inclusion. The main outcome measure was in-hospital mortality using age-adjusted cohorts and expanded lactate thresholds with secondary outcomes comparing mortality based on the primary clinical impression.

RESULTS

Of the 8796 patients in this analysis, there were 474 (5.4%) deaths. Mortality rates increased with both increasing lactate levels and increasing age. For all ages, mortality rates increased from 2.8% in the less than 2.0 millimoles per liter (mmol/L) lactate level, to 5.6% in the 2.0-2.9 mmol/L lactate level, to 8.0% in the 3.0-3.9 mmol/L lactate level, to 13.9% in the 4.0-4.9 mmol/L lactate level, to 13.7% in the 5.0-5.9 mmol/L lactate level, and to 39.1% in the 6.0 mmol/L or greater lactate level (p <0.0001). Survivors, regardless of age, had a mean lactate level <2.0 whereas non-survivors had mean lactate levels of 6.5, 4.5, and 3.7 mmol/L for age cohorts 18-39, 40-64, and ≥ 65 years, respectively.

CONCLUSION

Our findings suggest that although lactate levels can be used as a prognostic tool to risk stratify ED patients, the traditional lactate level thresholds may need to be adjusted to account for varying risk based on age and clinical impressions.

[Lactate in emergency medicine]

The basis of all metabolic processes in the human body is the production and metabolism of carriers of energy. Lactate is the end-product of anaerobic glycolysis. Lactate can serve as a substrate for gluconeogenesis and as an oxidation substrate. Hyperlactatemia can be detected as the result of a multitude of acute events (e.g. shock, sepsis, cardiac arrest, trauma, seizure, ischemia, diabetic ketoacidosis, thiamine deficiency, liver failure and intoxication). Hyperlactatemia can be associated with increased mortality, therefore in emergency medicine the search for the cause of hyperlactatemia is just as important as an effective causal treatment. Repetitive measurements of lactate are components of several treatment algorithms as observation of the dynamic development of blood lactate concentrations can help to make a better assessment of the acute medical condition of the patient and to evaluate the effectiveness of the measures undertaken.

Prognostic Significance of Arterial Lactate Levels at Weaning from Postcardiotomy Venoarterial Extracorporeal Membrane Oxygenation

BACKGROUND

The outcome after weaning from postcardiotomy venoarterial extracorporeal membrane oxygenation (VA-ECMO) is poor. In this study, we investigated the prognostic impact of arterial lactate levels at the time of weaning from postcardiotomy VA.

METHODS

This analysis included 338 patients from the multicenter PC-ECMO registry with available data on arterial lactate levels at weaning from VA-ECMO.

RESULTS

Arterial lactate levels at weaning from VA-ECMO (adjusted OR 1.426, 95%CI 1.157-1.758) was an independent predictor of hospital mortality, and its best cutoff values was 1.6 mmol/L (<1.6 mmol/L, 26.2% vs. ≥ 1.6 mmol/L, 45.0%; adjusted OR 2.489, 95%CI 1.374-4.505). When 261 patients with arterial lactate at VA-ECMO weaning ≤2.0 mmol/L were analyzed, a cutoff of arterial lactate of 1.4 mmol/L for prediction of hospital mortality was identified (<1.4 mmol/L, 24.2% vs. ≥1.4 mmol/L, 38.5%, p = 0.014). Among 87 propensity score-matched pairs, hospital mortality was significantly higher in patients with arterial lactate ≥1.4 mmol/L (39.1% vs. 23.0%, p = 0.029) compared to those with lower arterial lactate.

CONCLUSIONS

Increased arterial lactate levels at the time of weaning from postcardiotomy VA-ECMO increases significantly the risk of hospital mortality. Arterial lactate may be useful in guiding optimal timing of VA-ECMO weaning.