Emergency department lactate is associated with mortality in older adults admitted with and without infections

Association between lactate determined at emergency department arrival and the probability of inhospital mortality and intensive care admission in elderly patients

BACKGROUND AND IMPORTANCE

Elderly patients often have atypical clinical presentations. Lactate measurement on arrival at the Emergency Department (ED) could be useful to identify elderly patients with a bad prognosis.

OBJECTIVE

The study aimed to investigate the relationship between serum lactate determined at ED arrival and the probability of inhospital mortality and intensive care (ICU) admission in elderly patients.

DESIGN

Retrospective multipurpose registry. Secondary analysis of the EDEN cohort (Elderly Department and Elder Needs).

SETTINGS AND PARTICIPANTS

All patients ≥65 years attending 52 Spanish EDs during 2 week and in whom serum lactate was determined at ED arrival.

OUTCOME MEASURES AND ANALYSIS

The relationship between serum lactate values and the risk of inhospital all-cause death and transfer from the ED to the ICU was assessed by unadjusted and adjusted logistic regression assuming linearity and restricted cubic spline models assuming nonlinearity.

RESULTS

The cohort included 25 557 patients. The 3024 patients in whom lactate was measured were analyzed. The median age was 81 years (74-87), 1506 (27.2%) were women, 591 (19.5%) had serious comorbidities, 475 (15.7%) severe dependency, and 648 (21.4%) dementia. Death occurred during hospitalization in 217 patients (7.2%) and 53 patients (1.75%) were admitted to the ICU. Serum lactate values were nonlinear related to inhospital mortality and ICU admission. Serum lactate >3.1 mmol/L [odds ratio (OR): 1.60, 95% confidence interval (CI): 1.02-2.50] for inhospital mortality and 3.2 mmol/L (OR: 2.83, 95% CI: 1.03-6.79) for ICU admission were associated with significantly increased ORs in the adjusted models.

CONCLUSION

Serum lactate measured at ED arrival has a significant and exponential relationship with inhospital mortality and ICU admission in elderly patients.

Prehospital lactate analysis in suspected sepsis improves detection of patients with increased mortality risk: an observational study

BACKGROUND

Rapid, adequate treatment is crucial to reduce mortality in sepsis. Risk stratification scores used at emergency departments (ED) are limited in detecting all septic patients with increased mortality risk. We assessed whether the addition of prehospital lactate analysis to clinical risk stratification tools improves detection of patients with increased risk for rapid deterioration and death in sepsis.

METHODS

A10-month observational study with consecutive, prospective prehospital inclusion of adult patients with suspected sepsis. Prehospital lactate was used as a continuous variable and in intervals. Analyses of patient subgroups with high and lower priorities according to Rapid Emergency Triage and Treatment System (RETTS) and National Early Warning Score 2 (NEWS2) were performed. Primary outcome was 30-day mortality, secondary outcomes were sepsis at the ED and in-hospital mortality.

RESULTS

In all, 714 patients were included with a 30-day mortality of 10%. Among the 322 cases (45%) fulfilling Sepsis-3 criteria, the 30-day mortality was 14%. Prehospital lactate was higher among non-survivors (2.6 vs 2.0 mmol/L, p < 0.001). Mortality at different lactate intervals were: 6.7%, at 0-2 mmol/l; 10.0% at > 2-3 mmol/l; 19.2% at > 3-4 mmol/l; and 17.0% at levels > 4 mmol/l. The highest RETTS priority (red) group had higher lactate levels than the lower (non-red) priority group (2.5 vs 1.9 mmol/L, p < 0.001). In the non-red group, prehospital lactate was higher among non-survivors (2.4 vs 1.8 mmol/L, p = 0.002). In the multivariable regression analysis, prehospital lactate > 3 mmol/l was a predictor of 30-day mortality (OR 2.20, p = 0.009) This association was even stronger in the lower priority RETTS non-red group (OR 3.02, p = 0.009). Adding prehospital lactate > 3 mmol/l increased identification of non-survivors from 48 to 68% in the RETTS red group and from 77 to 85% for the NEWS2 ≥ 7 group.

CONCLUSION

The addition of a prehospital lactate level > 3 mmol/l improved early recognition of individuals with increased mortality risk in a cohort with suspected sepsis admitted to the ED. This was particularly evident in patients whose risk stratification scores did not indicate severe illness. We suggest that the addition of prehospital lactate analysis could improve recognition of subjects with suspected sepsis and increased mortality risk.

Utilizing point-of-care lactate testing for rapid prediction of clinical outcomes in patients with acute gastrointestinal bleeding in the emergency department

Objectives

We aimed to rapidly predict the prognosis of patients who present to the emergency department (ED) with acute gastrointestinal bleeding (AGIB) using point-of-care (POC) lactate testing.

Methods

This single-center retrospective observational study included 327 patients (survival group, 287; non-survival group, 40) who presented to the ED with AGIB between March 2021 and February 2022. We compared POC-measured lactate levels with laboratory-measured lactate levels using Pearson's correlation. Multivariate logistic regression analysis was used to identify early predictors of in-hospital mortality and correlated clinical outcomes. Receiver operating characteristic (ROC) curves were used to determine the optimal cutoff for POC-measured lactate levels for predicting in-hospital mortality, and the ROC curves for POC-measured lactate levels and AIMS65 scores were compared using the DeLong test.

Results

POC-measured lactate levels strongly correlated with laboratory-measured lactate levels (R2 = 0.82). Patients in the non-survival group had higher POC-measured lactate levels than did those in the survival group (2.6 mmol/L vs. 1.4 mmol/L, p < 0.001). POC-measured lactate level, age, systolic blood pressure, heart rate, and malignancy were identified as early predictors of in-hospital mortality (adjusted odds ratio [aOR] for POC-measured lactate levels: 1.15; 95 % confidence interval [CI] 1.02-1.30). The optimal POC-measured lactate level cutoff was 3.2 mmol/L. Areas under the ROC curves for POC-measured lactate level and the AIMS65 score were 0.70 and 0.73, respectively, showing statistical compatibility. Higher POC-measured lactate levels correlated with ICU admission, blood transfusion, and mechanical ventilation (aOR: 1.16, 95 % CI 1.05-1.27; 1.16, 1.04-1.30; and 1.31, 1.13-1.53, respectively]. Further, the hyperlactatemia subgroup (POC-measured lactate level ≥3.2 mmol/L) exhibited a lower survival probability in the Kaplan-Meier survival analysis (p < 0.01).

Conclusions

Our study shows that rapidly obtainable POC-measured lactate levels are valuable for predicting critical outcomes in AGIB patients and should be considered an early prognostic indicator for in-hospital mortality in the ED.

Relationship between lactate and thiamine-responsive disorders in hospitalised infants and children in Lao PDR: secondary analysis of a prospective cohort study

BACKGROUND

Lactate is a by-product of thiamine-deficient cellular metabolism, and hyperlactataemia can indicate severe illness. However, little is known about the clinical significance of hyperlactataemia in thiamine deficiency disorders.

AIM

To describe the relationship between whole-blood lactate level and thiamine-responsive disorders (TRDs) in children with signs/symptoms of thiamine deficiency in a high-risk region.

METHODS

This is a secondary analysis of data from the Lao Thiamine study, a prospective cohort study which enrolled hospitalised infants and children (aged 21 days to <18 months) who had at least one sign or symptom suggestive of thiamine deficiency in Lao PDR. Therapeutic thiamine was administered, and clinical evaluations were completed at several time-points over the next 72 h. Three paediatricians reviewed individual case reports to evaluate clinical response to thiamine and assigned TRD status. Data from 402 children were analysed by logistic regression and predictive modelling to examine the relationship between hyperlactataemia and TRDs.

RESULTS

Baseline hyperlactataemia (lactate >4.0 mmol/L) was associated with an increased odds of clinical improvement after thiamine administration [OR (95% CI) 2.32 (1.28-4.45), p = 0.007]. Baseline hyperlactataemia was a significant predictor of thiamine deficiency (thiamine diphosphate <40 nmol/L) [area under the receiver operating curve (95% CI) 0.76 (0.67-0.84), p < 0.001], and increased odds of mortality [OR (95% CI) 3.51 (1.38-8.94), p = 0.009].

CONCLUSIONS

In children with signs/symptoms of thiamine deficiency, hyperlactataemia is associated with a favourable clinical response to thiamine, biochemical thiamine deficiency, and increased odds of mortality. Lactate may be useful in identifying children who might benefit from therapeutic thiamine.

Severe hyperlactatemia in the emergency department: clinical characteristics, etiology and mortality

BACKGROUND

Severe hyperlactatemia (lactate level ≥ 10 mmol/L) is associated with high mortality rates in critically ill patients. However, there is limited data on emergency department (ED) patients. We aimed to investigate the clinical characteristics, etiology and outcomes of patients with severe hyperlactatemia in the ED setting.

METHODS

A retrospective cohort study was conducted at a tertiary care hospital in Thailand. We included adult patients with a venous lactate sample taken in the ED within one hour. We excluded patients after out-of-hospital cardiac arrest, transferred to/from another hospital or those with missing clinical data. Mortality rates were evaluated among patients with increasing degrees of lactate elevation and among patients with severe hyperlactatemia, stratified by causative etiology.

RESULTS

We analyzed venous lactate levels in 40,047 patients, with 26,680 included in the analysis. Among these, 1.7% had severe hyperlactatemia (lactate ≥ 10 mmol/L), 10.5% moderate (4-9.99 mmol/L), 28.8% mild (2-3.99 mmol/L), and 59.0% normal levels (< 2 mmol/L). Severe hyperlactatemia was associated with high mortality rates of 29%, 37%, and 38% at 7, 28, and 60 days respectively, significant ICU admissions and mechanical ventilation rates. Patients with severe hyperlactatemia were stratified into high (> 50% mortality), moderate (21-50%), and low (< 20%) 28-day mortality risk groups. High-risk conditions included non-septic shock, traumatic injuries/burns, and neurological issues, with mortality rates of 51.1%, 61.8%, and 57.1%, respectively. In the moderate risk group, namely infection without shock showed a high prevalence, with a mortality rate of 36%. In the low-risk group, seizures and fainting were associated with lower mortality, exhibiting mortality rates of 0%.

CONCLUSIONS

Severe hyperlactatemia is associated with higher rates of ICU admission and mortality compared to other degrees of lactate elevation in a general ED population. However, mortality rates can vary considerably, depending on the underlying etiology associated with different primary diagnoses.

The Respiratory Adjusted Shock Index at Admission Is a Valuable Predictor of In-Hospital Outcomes for Elderly Emergency Patients with Medical Diseases at a Japanese Community General Hospital

Background: The respiratory adjusted shock index (RASI) is a risk score whose usefulness in patients with sepsis and trauma has previously been reported. However, its relevance in elderly emergency patients with medical diseases is yet to be clarified. This study assessed the usefulness of the RASI, which can be evaluated without requiring special equipment, to provide objective and rapid emergency responses. Methods: In this retrospective study, we recruited patients with medical diseases, aged 65 years or older, who were transported to the emergency room from Tokushima Prefectural Kaifu Hospital and underwent arterial blood gas testing from 1 January 2022 to 31 December 2023. We investigated the association of the RASI with other indices, including the lactate level, National Early Warning Score 2 (NEWS2), Shock Index (SI), Sequential Organ Failure Assessment (SOFA) score, quick SOFA (qSOFA) score, and systemic inflammatory response syndrome (SIRS). Results: In this study, we included 260 patients (mean age, 86 years), of whom 234 were admitted to the hospital; 27 and 49 patients died within 7 and 30 days of admission, respectively. The RASI was positively correlated with the lactate level, NEWS2, SI, and increase in the SOFA score (p < 0.001). The RASI was higher in patients with a SIRS or qSOFA score ≥ 2 than in those without (p < 0.001). It predicted death within 7 and 30 days of admission with an area under the curve (AUC) of 0.80 (95% confidence interval [CI]: 0.73-0.87), sensitivity of 96.3%, and specificity of 53.6% when the cutoff value was set to 1.58 and with an AUC of 0.73 (95% CI: 0.66-0.81), sensitivity of 69.4%, and specificity of 70.6% when the cutoff value was set to 1.83, respectively. Conclusions: The RASI is a simple indicator that can be used for predicting in-hospital outcomes in elderly emergency patients with medical diseases. Larger prospective studies based on this study are needed.

Serum lactate and the mortality of critically ill patients in the emergency department: A retrospective study

Serum lactate levels have been widely studied as a prognostic marker in critically ill patients, particularly those in the intensive care unit. However, it remains unknown whether the serum lactate levels affect the mortality rate of critically ill patients admitted to hospital. To investigate this hypothesis, the vital signs and blood gas analysis data of 1,393 critically ill patients who visited the Emergency Department of Affiliated Kunshan Hospital of Jiangsu University (Kunshan, China) between January and December 2021 were collected. Patients were divided into two groups, 30-day survival group and a 30-day death group, and logistic regression analysis was used to investigate the association between vital signs, laboratory results and mortality rates of critically ill patients. A total of 1,393 critically ill patients was enrolled in the present study, with a male-to-female ratio of 1.17:1.00, a mean age of 67.72±19.29 years and a mortality rate of 11.6%. The multivariate logistic regression analysis revealed that increased serum lactate levels were an independent risk factor for mortality rate of critically ill patients [Odds ratio (OR)=1.50, 95% confidence interval (95% CI): 1.40-1.62]. The critical cut-off value for the serum lactate levels was identified as 2.35 mmol/l. In addition, OR values of age, heart rate, systolic blood pressure, transcutaneous oxygen saturation (SpO₂) and hemoglobin were 1.02, 1.01, 0.99, 0.96 and 0.99, respectively (95% CI: 1.01-1.04, 1.00-1.02, 0.98-0.99, 0.94-0.98 and 0.98-1.00, respectively). The logistic regression model was found to be of value in terms of identifying the mortality rate of patients and the area under the receiver operating characteristic curve was 0.894 (95% CI: 0.863-0.925; P<0.001). In conclusion, the present study showed that high serum lactate levels in critically ill patients upon admission to hospital are associated with higher 30-day mortality rate.

Role of serum lactate as prognostic marker of mortality among emergency department patients with multiple conditions: A systematic review

Objective

In the Emergency Department, the physician's purpose is to rapidly and accurately diagnose the severity of a patient's condition so that proper treatment can be administered. Therefore, this study pays close attention to the association and prognostic value of blood lactate on different disease outcomes by systematically reviewing recently published studies.

Methods

The search strategy was developed based on searches in the year 2022 for potential publications including original articles, case reports, and reviews using the following web databases google scholar, PubMed, and Science Direct. A total of 25 studies were identified and reviewed extensively to evaluate the link between mortality and serum lactate levels.

Results

This literature review presents the strong association of elevated serum lactate levels with the in-hospital mortality rate among emergency department patients.

Conclusion

These findings suggest that even a moderately raised lactate level in serum can predict the severe outcome in emergency department patients suffering from different conditions. Therefore, early (at the time of administration of hospital) and periodic serum lactate value determination through different techniques and scores is of need and should become part of routine analyses in emergency department to predict and choose therapies that could benefit critically ill patients.

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.

Expression of polyamines and its association with GnRH-I in the hypothalamus during aging in rodent model

GnRH-I and GnIH are the key neuropeptides that regulate the hypothalamic-pituitary-gonadal axis in mammals during aging. Polyamines are important aliphatic amines that are expressed in the brain and show variation with aging. The present study demonstrates evidence of variation in the level of expression of polyamines, GnRH-I and GnIH in the hypothalamus of female mice during aging. The study also suggests regulatory effects of polyamines over expression of the hypothalamic GnRH-I. The study shows a significant positive correlation between polyamines, its associated factors and GnRH-I along with significant negative correlation between polyamines, its associated factors and GnIH. This is the first study to report the effect of polyamines along with lactate or TNF-α or both on GnRH-I expression in GT1-7 cell line. TNF-α and lactate significantly decreased hypothalamic GnRH-I mRNA expression in GT1-7 cells when treated for 24 h. Polyamines (putrescine and agmatine) in contrast, significantly increased GnRH-I mRNA expression in GT1-7 cells when treated for 24 h. Also, polyamines increased GnRH-I mRNA expression when treated in presence of TNF-α or lactate thereby suggesting its neuro-protective role. This study also found 3809 differentially expressed genes through RNA-seq done between the hypothalamic GT1-7 cells treated with putrescine only versus TNF-α and putrescine. The present study suggests for the first time that putrescine treatment to TNFα-primed GT1-7 cells upregulates GnRH-I expression via regulation of several pathways such as calcium ion pathway, estrogen signaling, clock genes as well as regulating other metabolic process like neuronal differentiation and neurulation.

[Prognostic power of soluble urokinase plasminogen activator receptor (suPAR) for short-term mortality in patients seen in Emergency Departments due to infections]

OBJECTIVE

To analyse and compare 30-day mortality prognostic power of several biomarkers (C-reactive protein, procalcitonin, lactate and suPAR) in patients seen in emergency departments (ED) due to infections. Secondly, if these could improve the accuracy of systemic inflammatory response syndrome (SIRS) and quick Sepsis-related Organ Failure Assessment (qSOFA).

METHODS

A prospective, observational and analytical study was carried out on patients who were treated in an ED of one of the eight participating hospitals. An assessment was made of 32 independent variables that could influence mortality at 30 days. They covered epidemiological, comorbidity, functional, clinical and analytical factors.

RESULTS

The study included 347 consecutive patients, 54 (15.6%) of whom died within 30 days of visiting the ED. SUPAR has got the best biomarker area under the curve (AUC)-ROC to predict mortality at 30 days of 0.836 (95% CI: 0.765-0.907; P <.001) with a cut-off > 10 ng/mL who had a sensitivity of 70% and a specificity of 86%. The score qSOFA ≥ 2 had AUC-ROC of 0.707 (95% CI: 0.621-0.793; P < .001) with sensitivity of 53% and a specificity of 89%. The mixed model (suPAR > 10 ng/mL plus qSOFA ≥ 2) has improved the AUC-ROC to 0.853 [95% CI: 0.790-0.916; P < .001] with the best prognostic performance: sensitivity of 39% and a specificity of 97% with a negative predictive value of 90%.

CONCLUSIONS

suPAR showed better performance for 30-day mortality prognostic power from several biomarkers in the patients seen in ED due to infections. Score qSOFA has better performance that SRIS and the mixed model (qSOFA ≥ 2 plus suPAR > 10 ng/mL) increased the ability of qSOFA.

Serum Lactate for Predicting Cardiac Arrest in the Emergency Department

Objectives: Early recognition and prevention of in-hospital cardiac arrest (IHCA) play an increasingly important role in the Chain of Survival. However, clinical tools for predicting IHCA in the emergency department (ED) are scanty. We sought to evaluate the role of serum lactate in predicting ED-based IHCA. Methods: Data were retrieved from 733,398 ED visits over a 7-year period in a tertiary medical centre. We selected one ED visit per person and excluded out-of-hospital cardiac arrest, children, or those without lactate measurements. Patient demographics, computerised triage information, and serum lactate levels were extracted. The initial serum lactate levels were grouped into normal (≤2 mmol/L), moderately elevated (2 < lactate ≤ 4), and highly elevated (>4 mmol/L) categories. The primary outcome was ED-based IHCA. Results: A total of 17,392 adult patients were included. Of them, 342 (2%) developed IHCA. About 50% of the lactate levels were normal, 30% were moderately elevated, and 20% were highly elevated. In multivariable analysis, the group with highly elevated lactate had an 18-fold increased risk of IHCA (adjusted odds ratio [OR], 18.0; 95% confidence interval [CI], 11.5-28.2), compared with the normal lactate group. In subgroup analysis, the poor lactate-clearance group (<2.5%/h) was associated with a 7.5-fold higher risk of IHCA (adjusted OR, 7.5; 95%CI, 3.7-15.1) compared with the normal clearance group. Conclusions: Elevated lactate levels and poor lactate clearance were strongly associated with a higher risk of ED-based IHCA. Clinicians may consider a more liberal sampling of lactate in patients at higher risk of IHCA with follow-up of abnormal levels.

A portable blood lactate sensor with a non-immobilized enzyme for early sepsis diagnosis

Early determination of blood lactate levels may accelerate the detection of sepsis, one of the most time-sensitive illnesses.

Molecular dynamics of estrogen-related receptors and their regulatory proteins: roles in transcriptional control for endocrine and metabolic signaling

Estrogen-related receptor (ERR) is a member of the nuclear receptor (NR) superfamily and has three subtypes α, β, and γ. Despite their strong homology with estrogen receptor (ER) α, ERRs cannot accommodate endogenous hormones. However, they are able to regulate gene expression without ligand binding. ERRα and ERRγ orchestrate the expression of genes involved in bioenergetic pathways, while ERRβ controls placental development and stem cell maintenance. Evidence from recent studies, including clinical research, has also demonstrated close associations of ERRs with the pathophysiology of hormone-related cancers and metabolic disorders including type 2 diabetes mellitus. This review summarizes the basic knowledge and recent advances in ERRs and their associated proteins, focusing on the subcellular dynamics involved in transcriptional regulation. Fluorescent protein labeling enabled monitoring of ERRs in living cells and revealed previously unrecognized characteristics. Using this technique, we demonstrated a role of ERRβ in controlling estrogen signaling by regulating the subnuclear dynamics of ligand-activated ERα. Visualization of ERRs and related proteins and subsequent analyses also revealed a function of ERRγ in promoting liver lactate metabolism in association with LRPGC1, a recently identified lactic acid-responsive protein. These findings suggest that ERRs activate unique transregulation mechanisms in response to extracellular stimuli such as hormones and metabolic signals, implying an adaptive system behind the cellular homeostatic regulation by orphan NRs. Control of subcellular ERR dynamics will contribute toward the development of therapeutic approaches to treat various diseases including hormone-related cancers and metabolic disorders associated with abnormal ERR signaling pathways.

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

BACKGROUND AND AIMS

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

APPROACH AND RESULTS

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

CONCLUSIONS

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

What Is the Utility of Measuring Lactate Levels in Patients with Sepsis and Septic Shock?

Elevations in blood lactate concentrations have been studied in sepsis and other disease states for decades and are well known to be associated with increased mortality. Many studies have also demonstrated the prognostic accuracy of serial lactate levels, and some have suggested that lactate clearance may be a useful therapeutic target for resuscitation. Lactate measurements have therefore gained an increasingly prominent role in sepsis definitions, screening protocols, management guidelines, and quality measures over the past two decades. The heavy emphasis on lactate monitoring, however, has also generated controversy and concerns. Lactate is not specific to infection and its frequent use for sepsis screening and diagnosis may therefore trigger unnecessary broad-spectrum antibiotic use in some patients. Because hyperlactatemia does not always reflect fluid-responsive hypoperfusion, titrating resuscitation to lactate clearance can also lead to unnecessary fluid and volume overload. More broadly, there is a lack of high-quality evidence demonstrating that initial and serial lactate monitoring leads to better patient-centered outcomes. Indeed, a recent randomized controlled trial comparing resuscitation strategies based on lactate clearance versus normalizing capillary refill time showed no benefit and potential harm with lactate-guided therapy. In this article, we review the basic pathobiology of lactate metabolism and delineate why the traditional paradigm that hyperlactatemia reflects tissue hypoxia is overly simplistic and incomplete. We then review the evidence behind the diagnostic, prognostic, and therapeutic uses of lactate monitoring and place this in the context of evolving sepsis diagnosis and management guidelines.

Prognostic utility of lactate concentrations and kinetics to predict adverse events associated with acute drug overdose

OBJECTIVE

Clinical research on drug intoxication is necessary for appropriate action in emergency departments (EDs). However, currently, there are no evident biomarkers for predicting adverse events (AEs) in patients with drug intoxication. We aimed to evaluate the prognostic value of serum lactate concentrations and lactate kinetics for AEs such as cardiogenic or respiratory failure in patients admitted to the ED with acute drug overdose.

METHODS

We conducted a single-center retrospective study by reviewing the prospective suicide registry of patients visiting the ED. The primary outcome was composite AEs at any point during the ED visit or hospital stay.

RESULTS

A total of 566 patients with acute drug overdose were enrolled in this study. Of these, 62 patients had AEs, whereas 363 patients did not, yielding an AE rate of 14.6%. The median 0 h lactate concentrations in the AE and non-AE groups were 2.7 [2.1-5.1] mmol/L and 2.1 [1.4-2.9] mmol/L, respectively (p < 0.001). The median 6 h lactate concentrations in the AE and non-AE groups were 2.0 [1.5-3.9] mmol/L and 1.3 [0.9-2.2] mmol/L, respectively (p < 0.001). The area under the curve of lactate at 0 h for predicting AEs was 0.705 (95% CI: 0.659-0.748). The optimal lactate cutoff point was 4.2 mmol/L (37.1% sensitivity, 92.8% specificity). Multivariable analysis using a stepwise backward method showed that the 0 h lactate concentration was associated with AEs in acute drug intoxication after adjusting for confounders (adjusted OR of 0 h lactate, 1.47; 95% CI, 1.23-1.77). However, the 6 h lactate concentrations, lactate clearance, and delta lactate levels did not predict the outcomes.

CONCLUSION

Lactate concentrations and kinetics in patients admitted to the ED with an acute drug overdose exhibited limited prognostic utility in predicting AEs and should be interpreted with caution when considered for clinical decision-making.

Evaluation of the Prognostic Value of Lactate and Acid-Base Status in Patients Presenting to the Emergency Department

Background

Lactate levels predict mortality in a wide range of patients presenting to the Emergency Department (ED); however, the effect of co-existing acidosis is unknown. Here, we investigated the effect of acidosis on in-hospital mortality for patients with hyperlactataemia.

Methodology

This is a retrospective cohort study of adults cared for in the resuscitation area of one ED who received a metabolic panel on arrival. The primary outcome was in-hospital mortality for patients with normal lactate (0.0-2.0 mmol/L), intermediate lactate (2.1-4.0 mmol/L), or high lactate (>4.0 mmol/L), with and without acidosis. Odds ratios (ORs) were calculated to assess the differences in mortality rates between groups stratified by lactate and acid-base status.

Results

A total of 4,107 metabolic panels were collected and 3,238 were assessed. In total, 510 (15.8%) and 784 (24.2%) patients had a normal lactate and acidosis/no acidosis; 587 (18.1%) and 842 (26.0%) had intermediate lactate and acidosis/no acidosis; and 388 (12.0%) and 127 (3.9%) had high lactate and acidosis/no acidosis, respectively. The overall mortality was 5%. Mortality was 4.3%/0.6% in the normal lactate, 5.6%/2.6% in the intermediate lactate, and 19.3%/3.9% in the high lactate groups, with and without acidosis, respectively. Combining base excess <-6 and lactate >4 mmol/L had a sensitivity of 39%, specificity of 96%, positive predictive value of 32%, and negative predictive value of 98% for in-hospital mortality (OR: 14.0; 95% confidence interval: 9.77-20.11).

Conclusions

In an undifferentiated cohort of ED patients presenting to the resuscitation area lactaemia associated with acidosis is a more accurate predictor of in-hospital mortality than hyperlactataemia.

Value of biomarkers in predicting mortality in older medical emergency department patients: a Dutch prospective study

OBJECTIVE

Older emergency department (ED) patients are at high risk of mortality, and it is important to predict which patients are at highest risk. Biomarkers such as lactate, high-sensitivity cardiac troponin T (hs-cTnT), N-terminal pro-B-type natriuretic peptide (NT-proBNP), D-dimer and procalcitonin may be able to identify those at risk. We aimed to assess the discriminatory value of these biomarkers for 30-day mortality and other adverse outcomes.

DESIGN

Prospective cohort study. On arrival of patients, five biomarkers were measured. Area under the curves (AUCs) and interval likelihood ratios (LRs) were calculated to investigate the discriminatory value of the biomarkers.

SETTING

ED in the Netherlands.

PARTICIPANTS

Older (≥65 years) medical ED patients, referred for internal medicine or gastroenterology.

PRIMARY AND SECONDARY OUTCOME MEASURES

30-day mortality was the primary outcome measure, while other adverse outcomes (intensive care unit/medium care unit admission, prolonged length of hospital stay, loss of independent living and unplanned readmission) were the composite secondary outcome measure.

RESULTS

The median age of the 450 included patients was 79 years (IQR 73-85). In total, 51 (11.3%) patients died within 30 days. The AUCs of all biomarkers for prediction of mortality were sufficient to good, with the highest AUC of 0.73 for hs-cTnT and NT-proBNP. Only for the highest lactate values, the LR was high enough (29.0) to be applicable for clinical decision making, but this applied to a minority of patients. The AUC for the composite secondary outcome (intensive and medium care admission, length of hospital stay >7 days, loss of independent living and unplanned readmission within 30 days) was lower, ranging between 0.58 and 0.67.

CONCLUSIONS

Although all five biomarkers predict 30-day mortality in older medical ED patients, their individual discriminatory value was not high enough to contribute to clinical decision making.

TRIAL REGISTRATION NUMBER

NCT02946398; Results.

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.

The role of the serum lactate level at the first admission to the emergency department in predicting mortality

INTRODUCTION

Lactate is an easily measurable laboratory parameter that is considered a potentially useful prognostic marker for determining risk in emergency department patients. The aim of this study was to investigate the role of serum lactate in the patients who were admitted to the emergency department at the time of admission.

METHODS

Patients who were admitted to the emergency department for various reasons between June 2017 and January 2018 were included in the study. Demographic data, laboratory findings, mortality and hospitalization rates of the patients were analyzed. The primary endpoint was determined as the role of serum lactate in predicting mortality, and the secondary endpoint in predicting hospitalization.

RESULTS

Of the 1382 patients, 47.4% (n = 655) were female and 52.6% (n = 727) were male. The mean age of the patients was 60.99 ± 20.04 (18-100) years. In 59.6% (n = 824) of the patients, the most common hypertension (36%) was an additional disease. Mortality was found in 43 (3.1%) patients. It was observed that 20.5% (n = 284) of the patients were hospitalized. The ages of patients with hospitalization and mortality were found to be statistically significant higher than those without hospitalization and without mortality (p = 0.001; p < 0.01). There was no statistically significant difference between the serum lactate measurements of the patients according to hospitalization (p > 0.05). The serum lactate levels of the patients with mortality were found to be statistically significant higher than those without mortality (p = 0.001; p < 0.01). The cut off point for serum lactate level in predicting mortality was found to be ≥3.6 mmol/L. The mortality rate was found to be statistically significant higher in patients with serum lactate level 3,6 mmol/L and above (p = 0,001; p < 0,01).

CONCLUSION

In conclusion, we believe in the light of the findings of our study that the serum lactate level is effective and reliable in the prediction of mortality in patients who present to emergency department for any reason. However, prospective studies with broader patient groups are required in this subject.

Relative Hyperlactatemia in the Emergency Department

Objective: The clinical interpretation of lactate ≤ 2.00 mmol/L in emergency department (ED) patients is not well-characterized. This study aims to determine the optimal cutoff value for lactate within the reference range that predicts in-hospital mortality among ED patients. Methods: This was a retrospective study of adult patients presenting to a tertiary ED with an initial serum lactate level of <2.00 mmol/L. The primary outcome was in-hospital mortality. Youden's index was utilized to determine the optimal threshold that predicts mortality. Patients above the threshold were labeled as having relative hyperlactatemia. Results: During the study period, 1,638 patients were included. The mean age was 66.9 ± 18.6 years, 47.1% of the population were female, and the most prevalent comorbidity was hypertension (56.7%). The mean lactate level at presentation was 1.5 ± 0.3 mmol/L. In-hospital mortality was 3.8% in the overall population, and 16.2% were admitted to the ICU. A lactate level of 1.33 mmol/L was found to be the optimal cutoff that best discriminates between survivors and non-survivors. Relative hyperlactatemia was an independent predictor of in-hospital mortality (OR 1.78 C1.18-4.03; p = 0.02). Finally, relative hyperlactatemia was associated with increased mortality in patients without hypertension (4.7 vs. 1.1%; p = 0.008), as well as patients without diabetes or COPD. Conclusion: The optimal cutoff of initial serum lactate that discriminates between survivors and non-survivors in the ED is 1.33 mmol/L. Relative hyperlactatemia is associated with increased mortality in emergency department patients, and this interaction seems to be more important in healthy patients.

Novel metabolic system for lactic acid via LRPGC1/ERRγ signaling pathway

Lactic acid (LA) is a byproduct of glycolysis resulting from intense exercise or a metabolic defect in aerobic processes. LA metabolism is essential to prevent lactic acidosis, but the mechanism through which LA regulates its own metabolism is largely unknown. Here, we identified a LA-responsive protein, named LRPGC1, which has a distinct role from PGC1α, a key metabolic regulator, and report that LRPGC1 particularly mediates LA response to activate liver LA metabolism. Following LA stimulation, LRPGC1, but not PGC1α, translocates from the cytoplasm to the nucleus through deactivation of nuclear export signals, interacts with the nuclear receptor ERRγ, and upregulates TFAM, which ensures mitochondrial biogenesis. Knockout of PGC1 gene in HepG2 hepatocarcinoma cells decreased the LA consumption and TFAM expression, which were rescued by LRPGC1 expression, but not by PGC1α. These LRPGC1-induced effects were mediated by ERRγ, concomitantly with mitochondrial activation. The response element for LRPGC1/ERRγ signaling pathway was identified in TFAM promoter. Notably, the survival rate of a mouse model of lactic acidosis was reduced by the liver-targeted silencing of Lrpgc1, while it was significantly ameliorated by the pharmacological activation of ERRγ. These findings demonstrate LA-responsive transactivation via LRPGC1 that highlight an intrinsic molecular mechanism for LA homeostasis.

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.

Benefits of N-acetylcysteine on liver functions in living donor hepatectomy

Background and Aims:

The proportion of patients undergoing living donor liver transplantation is high especially in countries without or with limited cadaver organ sharing programs. The aim of this study was to evaluate the post-hepatectomy effect of using N-Acetylcysteine (NAC) infusion in living donors undergoing donor hepatectomy.

Methods:

In a prospective randomised non-blinded study, 50 healthy donors were enrolled; following hepatectomy patients were randomised into 2 groups: Group NC receiving NAC 150 mg/kg diluted in 100 ml glucose 5% over 40 minutes, followed by NAC 12.5 mg/kg in 500 ml glucose 5% over 4 hours. This was followed by NAC 6.25 mg/kg for 2 post-operative days, Group C (Control group) received ringer acetate infusion at same rate for 2 days. The primary outcome was serum lactate levels. Secondary outcomes were liver function tests, serum creatinine and urine output on intensive care unit (ICU) admission (0 hr.), after 24 hours and 48 hours, length of ICU stay.

Results:

Our study revealed significant reduction in serum lactate in Group NC at 0, 24 and 48 hours compared to C group (P = 0.017, 0.002, 0.014). INR values showed significant reduction after 48 hours in Group NC compared to Group C (P = 0.049). Total Bilirubin, ALT, and Creatinine, urine output and ICU stay showed no statistical difference between the 2 groups.

Conclusion:

The NAC protocol is a safe, cost-effective tool for improvement of post hepatectomy liver function and early stabilisation of the metabolic profile.

Contemporary Management of Acute Decompensated Heart Failure and Cardiogenic Shock

Cardiogenic shock (CS) is a life-threatening condition characterized by end-organ hypoperfusion and hypoxia primarily due to cardiac dysfunction and low cardiac output. Unfortunately, the mortality and morbidity associated with CS have remained high despite notable advances in heart failure management. Treatment should be carefully guided by hemodynamics assessment. Although inotropes, vasopressors, mechanical circulatory support, and catheter intervention for critical valve lesion are not always recommended, they are helpful in selected patients. Early diagnosis, accurate hemodynamic assessment, and prompt therapeutic intervention are crucial in the management of acute decompensated heart failure with CS.

The utility of point of care serum lactate in predicting serious adverse outcomes among critically ill adult patients at urban emergency departments of tertiary hospitals in Tanzania

Background

Elevated serum lactate levels have been shown in numerous studies to be associated with serious adverse events, including mortality. Point of care lactate level is increasingly available in resource-limited emergency department (ED) settings. However, little is known about the predictive ability of for serious adverse events.

Aim of the study

We aimed to describe the utility of serum lactate level as a predictor of 24-h serious adverse events among adult patients presenting at the Emergency Medicine Department (EMD) of Muhimbili National Hospital (MNH) and MUHAS Academic Medical Center (MAMC).

Methods

This was a prospective observational study involving adult patients presenting to the EMD-MNH and MAMC from 1 September 2018 and 31 October 2018. Eligible patients with at least one lactate level test drawn while in the ED were examined in terms of their demographics, relevant clinical characteristics, and any serious adverse event (SAE) within 24 h of arrival. The sensitivity and specificity of lactate level to predict outcomes of interest were determined using the best cut-off point constructed from AUROC to see how well lactate level could discriminate which patients would have adverse events in the next 24 h. Categorical and continuous variables were compared with the chi-square test and two-sample t test, respectively.

Results

We screened 2057 (20.9%) out of 9828 patients who presented during study period, and enrolled 387 (18.8%). The overall median age was 54 years (interquartile range 40–68 years) and 206 (53.2%) were male. Using local triaging system, a total of 322 (83.2%) was triaged as an emergency category. The mean lactate level was 3.2 ± 3.6 mmol/L, 65 (16.8%) patients developed at least one SAE, with 42 (11%) who required ICU/HDU, 37 (10%) needed ventilator support, 10 (3%) required inotropes, and 9 (2%) developed cardiac arrest. The overall 24-h mortality was 28 (7%). The AUC of serum lactate level for overall 24-h mortality was 0.801 (95%CI, 0.7–0.9, P ≤ 0.001). At the optimal cutoff value (3.8 mmol/L), lactate level had a sensitivity and specificity for 24-h mortality of 64% and 85%, respectively. Mortality of the high-lactate level group (³3.8 mmol/L) was significantly higher than that of the low-lactate level group (< 3.8 mmol/L), 23.8% vs. 2.9%, respectively (95%CI 3.8–17.2, p < 0.001), with the relative risk of mortality in the high-lactate level group being 8.1 times higher compared to the low-lactate level group.

Conclusion

The utility of lactate level in predicting mortality was similar to that seen in high-resource settings. A serum lactate level of ³3.8 mmol/L predicted 24-h serious adverse events in unselected patients seen in the high-acuity area of our ED. Incorporating serum lactate level in ED in lower- and middle-income countries (LMICs) can help identify patients at risk of developing serious adverse events.

High incidence of multiresistant bacterial isolates from bloodstream infections in trauma emergency department and intensive care unit in Serbia

We investigated the incidence of bloodstream infections (BSIs) in trauma emergency department (ED) and intensive care unit (ICU), to assess ED- and ICU-related predictors of BSI and to describe the most common bacteria causing BSI and their antimicrobial resistance markers. A prospective study was conducted in two trauma ICUs of the ED of Clinical Center of Serbia. Overall, 62 BSIs were diagnosed in 406 patients, of which 13 were catheter-related BSI (3.0/1,000 CVC-days) and 30 BSIs of unknown origin, while 15% were attributed to ED CVC exposure. Lactate ≥2 mmol/L and SOFA score were independent ED-related predictors of BSI, while CVC in place for >7 days and mechanical ventilation >7 days were significant ICU-related predictors. The most common bacteria recovered were Acinetobacter spp., Klebsiella spp., and Pseudomonas aeruginosa. All Staphylococcus aureus and coagulase-negative staphylococci isolates were methicillin-resistant, whereas 66% of Enterococcus spp. were vancomycin-resistant. All isolates of Enterobacteriaceae were resistant to third-generation cephalosporins, whereas 87.5% of P. aeruginosa and 95.8% of Acinetobacter spp. isolates were resistant to carbapenems. ED BSI contributes substantially to overall ICU incidence of BSI. Lactate level and SOFA score can help to identify patients with higher risk of developing BSI. Better overall and CVC-specific control measures in patients with trauma are needed.

Serum Lactate as an Independent Predictor of In-Hospital Mortality in Intensive Care Patients

PURPOSE

The aim of this study was to check if serum lactate was independently associated with mortality among critically ill patients.

MATERIALS AND METHODS

This was a single-center, retrospective cohort study. All adult patients (>18 years of age) who had at least 1 measurement of lactate within 24 hours of admission to intensive care unit (ICU) between January 2002 and December 2017 were included in the analysis. Patients were stratified into 3 groups: those with a serum lactate of <2 mmol/L (normal level), 2 to 4 mmol/L (intermediate level), and >4 mmol/L (high level). The primary outcome was in-hospital mortality. Secondary outcomes included ICU and hospital lengths of stay and mechanical ventilation duration. To determine the association between lactate level and hospital mortality, bivariate and multivariate logistic regression analyses were performed.

RESULTS

Of the 16,447 patients admitted to the ICU, 8167 (49.65%) had normal levels, 4648 (28.26%) had an intermediate, and 3632 (22.09%) had high lactate levels. Hospital mortality was the highest in high lactate level, followed by the intermediate and the normal level group (47.4% vs 26.5% vs 19.6%; P < .0001). Intermediate and high lactate levels were independent predictors of hospital mortality (odds ratio [OR], 1.32; 95% confidence interval [CI]: 1.20-1.46, and 1.94; 95% CI, 1.75-2.16, respectively) as well as ICU mortality (OR, 1.47; 95% CI, 1.30-1.66 and 2.56; 95% CI, 2.27-2.88, respectively).

CONCLUSIONS

Intensive care unit serum lactate is associated with increased ICU and hospital mortality, independent of comorbidities, organ dysfunction, or hemodynamic status.

Refractory Lactic Acidosis and an Approach to its Management - A Case Report

Background

Lactic acidosis (LA) is a complication of diseases commonly seen in intensive care patients which carries an increased risk of mortality. It is classified by its pathophysiology; Type A results from tissue hypo-perfusion and hypoxia, and Type B results from abnormal metabolic activity in the absence of hypoxia. Reports of the co-occurrence of both types have been rarely reported in the literature relating to intensive care patients. This case report describes the challenging management of a patient diagnosed with both Type A and Type B LA.

Case presentation

A 55-year-old female with newly diagnosed diffuse large B-cell lymphoma (DLBCL) developed hospital-acquired pneumonia, respiratory failure, shock and intra-abdominal septicaemia from a bowel perforation. Blood gases revealed a mixed picture lactic acidosis. Correction of septic shock, respiratory failure and surgical repair caused initial improvement to the lactic acidosis, but this gradually worsened in the intensive care unit. Only upon starting chemotherapy and renal replacement therapy was full resolution of the lactic acidosis achieved. The patient was discharged but succumbed to her DLBCL several months later.

Conclusion

Type A and Type B LA can co-occur, making management difficult. A systematic approach can help diagnose any underlying pathology and aid in early management.

[Comparison of different strategies for short-term death prediction in the infected older patient]

OBJECTIVE

The aim of this study was to determine the utility of a post hoc lactate added to SIRS and qSOFA score to predict 30-day mortality in older non-severely dependent patients attended for infection in the Emergency Department (ED).

METHODS

We performed an analytical, observational, prospective cohort study including patients of 75 years of age or older, without severe functional dependence, attended for an infectious disease in 69 Spanish ED for 2-day three seasonal periods. Demographic, clinical and analytical data were collected. The primary outcome was 30-day mortality after the index event.The antimicrobial susceptibility data and extended-spectrum beta-lactamase (ESBL) production in isolates recovered from intra-abdominal (IAI) (n=1,429) and urinary tract (UTI) (n=937) infections during the 2016- 2017 SMART study in 10 Spanish hospitals were analysed.

RESULTS

We included 739 patients with a mean age of 84.9 (SD 6.0) years; 375 (50.7%) were women. Ninety-one (12.3%) died within 30 days. The AUC was 0.637 (IC 95% 0.587-0.688; p<0.001) for SIRS ≥ 2 and 0.698 (IC 95% 0.635-0.761; p<0.001) for qSOFA ≥ 2. Comparing receiver operating characteristic (ROC) there was a better accuracy of qSOFA vs SIRS (p=0.041). Both scales improve the prognosis accuracy with lactate inclusion. The AUC was 0.705 (IC95% 0.652-0.758; p<0.001) for SIRS plus lactate and 0.755 (IC95% 0.696-0.814; p<0.001) for qSOFA plus lactate, showing a trend to statistical significance for the second strategy (p=0.0727). Charlson index not added prognosis accuracy to SIRS (p=0.2269) or qSOFA (p=0.2573).

CONCLUSIONS

Lactate added to SIRS and qSOFA score improve the accuracy of SIRS and qSOFA to predict short-term mortality in older non-severely dependent patients attended for infection. There is not effect in adding Charlson index.

Lactate and NEWS-L are fair predictors of mortality in critically ill geriatric emergency department patients

INTRODUCTION

In this study, we aimed to investigate the prognostic power of the first lactate level measured in the emergency department (ED), National Early Warning Score (NEWS), and NEWS-lactate (NEWS-L) on ED admission in critically ill geriatric patients.

METHODS

This retrospective observational study was conducted in the ED of a university hospital. Consecutive patients ≥65 years of age admitted to our ED between July 1, 2017, and December 31, 2017, and transferred to the intensive care unit after the ED follow-up period were included in the study. The predictive performances of lactate, NEWS, and NEWS-L in terms of in-hospital mortality were compared.

RESULTS

A total of 455 patients were included in the statistical analyses. The in-hospital mortality rate was 22.9%. The mean lactate, NEWS, and NEWS-L of non-survivors was significantly higher than those of survivors (2.9 ± 2.2 vs. 1.9 ± 1.5 mmol/L, 8.9 ± 4.1 vs. 6.1 ± 3.7, and 11.8 ± 5.0 vs. 8.1 ± 4.4, respectively, for all p < 0.001). The AUCs of the lactate, NEWS, and NEWS-L were respectively 0.654 (95% CI 0.594-0.713), 0.686 (95% CI 0.628-0.744), and 0.714 (95% CI 0.658-0.770) in predicting in-hospital mortality.

CONCLUSIONS

According to the results of this study, we conclude that ED admission lactate level and NEWS are low-accuracy predictors of in-hospital mortality in critically ill geriatric patients. Although the combination of lactate level with physiological parameters increases the predictive performances of both parameters, NEWS-L is still not a powerful predictor to make definitive clinical decisions for critically ill geriatric ED patients.

Usefulness of serum lactate as a predictor of successful discontinuation of continuous atropine infusion in patients with severe acute organophosphate poisoning

Objective

In severe organophosphate (OP) poisoning, administration of atropine via continuous intravenous infusion is typically considered. To date, there have been no studies on predicting successful atropine discontinuation through plasma cholinesterase (PChE) and serum lactate levels, which are monitored during critical care in severe acute OP poisoning. Therefore, we retrospectively evaluated the usefulness of serum lactate and PChE as predictors of successful discontinuation of atropine infusion.

Methods

This retrospective observational study was performed on consecutive adult patients treated for severe acute OP poisoning between March 2011 and December 2016. We sequentially evaluated serum lactate and PChE levels on emergency department arrival and before a discontinuation trial of atropine infusion. Discontinuation of atropine intravenous infusion was attempted in patients after clearance of respiratory secretions and cessation of bronchoconstriction. Discontinuation of atropine infusion attempts were divided into successful and failed trials.

Results

A total of 95 trials were conducted in 62 patients. Serum lactate levels before trials were significantly different between patients with successful and failed trials. The area under the curve for prediction of successful atropine discontinuation using serum lactate levels before trial discontinuation were 0.742 (95% confidence interval, 0.638 to 0.846). PChE level was not significantly different between two groups.

Conclusion

Serum lactate levels before the discontinuation trial of atropine infusion served to predict successful discontinuation in severe acute OP poisoning.

Prognostic Utility of Initial Lactate in Patients With Acute Drug Overdose: A Validation Cohort

STUDY OBJECTIVE

Previous studies have suggested that the initial emergency department (ED) lactate concentration may be an important prognostic indicator for inhospital mortality from acute drug poisoning. We conduct this cohort study to formally validate the prognostic utility of the initial lactate concentration in a larger, distinct patient population with acute drug overdose.

METHODS

This observational, prospective, cohort study was conducted during 5 years at 2 urban teaching hospitals. Consecutive adult ED patients with acute drug overdose had serum lactate levels tested as part of clinical care. The primary outcome was inpatient fatality. Receiver operating characteristics were plotted to determine optimal cut points, test characteristics, area under the curve, odds ratios, and 95% confidence intervals (CIs).

RESULTS

Of 3,739 patients screened, 1,406 were analyzed (56% women; mean age 43.1 years) and 24 died (1.7%). The difference in mean initial lactate concentration was 5.9 mmol/L (95% CI 3.4 to 8.1 mmol/L) higher in patients who died compared with survivors. The area under the curve for prediction of fatality was 0.85 (95% CI 0.73 to 0.95). The optimal lactate cut point for fatality was greater than or equal to 5.0 (odds ratio 34.2; 95% CI 13.7 to 84.2; 94.7% specificity). Drug classes for which lactate had the highest utility were salicylates, sympathomimetics, acetaminophen, and opioids (all area under the curve ≥0.97); lowest utility was for diuretics and angiotensin-converting enzyme inhibitors.

CONCLUSION

Initial lactate concentration is a useful biomarker for early clinical decisionmaking in ED patients with acute drug overdose. Studies of lactate-tailored management for these patient populations are warranted.

The Utility of Point-of-Care Testing at Emergency Department Triage by Nurses in Simulated Scenarios

We developed and tested simulated patient scenarios to assess how normal or abnormal point-of-care (POC) test results at triage change prioritization decisions. This was a cross-sectional study where our team developed simulated scenarios and presented them to triage nurses from 3 academic medical centers. Twenty-four scenarios were constructed on the basis of 12 clinical indications from a protocol previously developed by our team. In each scenario, nurses were presented with 2 patients with the same Emergency Severity Index Version 4 (ESI v.4; Agency for Healthcare Research and Quality, Rockville, MD) triage level (Level 2 or Level 3). One of the patients met the inclusion criteria for POC testing under the protocol (cases), whereas the other patient did not (controls). Nurses were asked which of the 2 patients to prioritize first in 3 separate rounds: first without any POC test results, once with abnormal POC test results for case patients, and once with normal POC test results for case patients. Prioritization decisions that changed on the basis of abnormal POC results were defined as "up-triage" and prioritization decisions that changed on the basis of normal results were defined as "down-triage." A total of 39 nurses completed 468 scenarios. In scenarios without any POC test results, 42.3% of case patients were prioritized first. When POC test results were abnormal, 71.6% of cases were prioritized first. When POC test results were normal, 32.7% of case patients were prioritized first. An abnormal POC test resulted in up-triage in 32.5% of the scenarios. When POC test results were normal, there was down-triage in 18.6% of the scenarios. Up- and down-triage rates varied considerably by scenario and clinical indication. Point-of-care testing at emergency department triage results in reasonably high rates of up- and down-triage in simulated scenarios; however, POC tests for specific indications appear to be more useful than others.

Repeat lactate level predicts mortality better than rate of clearance

BACKGROUND

Lactate clearance has been developed into a marker of resuscitation in trauma, but no study has compared the predictive power of the various clearance calculations. Our objective was to determine which method of calculating lactate clearance best predicted 24-hour and in-hospital mortality after injury.

STUDY DESIGN

Retrospective chart review of patients admitted to a Level-1 trauma center directly from the scene of injury from 2010 to 2013 who survived >15min, had an elevated lactate at admission (≥3mmol/L), followed by another measurement within 24h of admission. Lactate clearance was calculated using five models: actual value of the repeat level, absolute clearance, relative clearance, absolute rate, and relative rate. Models were compared using the areas under the respective receiver operating curves (AUCs), with an endpoint of death at 24h and in-hospital mortality.

RESULTS

3910 patients had an elevated admission lactate concentration on admission (mean=5.6±3.0mmol/L) followed by a second measurement (2.7±1.8mmol/L). Repeat absolute measurement best predicted 24-hour (AUC=0.85, 95% CI: 0.84-0.86) and in-hospital death (AUC=0.77; 95% CI, 0.76-0.78). Relative clearance was the best model of lactate clearance (AUC=0.77, 95% CI: 0.75-0.78 and AUC=0.705, 95% CI: 0.69-72, respectively) (p<0.0001 for each). A sensitivity analysis using a range of initial lactate measures yielded similar results.

CONCLUSIONS

The absolute value of the repeat lactate measurement had the greatest ability to predict mortality in injured patients undergoing resuscitation.

Lactate oxidation facilitates growth of Mycobacterium tuberculosis in human macrophages

Mycobacterium tuberculosis (Mtb) uses alveolar macrophages as primary host cells during infection. In response to an infection, macrophages switch from pyruvate oxidation to reduction of pyruvate into lactate. Lactate might present an additional carbon substrate for Mtb. Here, we demonstrate that Mtb can utilize L-lactate as sole carbon source for in vitro growth. Lactate conversion is strictly dependent on one of two potential L-lactate dehydrogenases. A knock-out mutant lacking lldD2 (Rv1872c) was unable to utilize L-lactate. In contrast, the lldD1 (Rv0694) knock-out strain was not affected in growth on lactate and retained full enzymatic activity. On the basis of labelling experiments using [U-¹³C₃]-L-lactate as a tracer the efficient uptake of lactate by Mtb and its conversion into pyruvate could be demonstrated. Moreover, carbon flux from lactate into the TCA cycle, and through gluconeogenesis was observed. Gluconeogenesis during lactate consumption depended on the phosphoenolpyruvate carboxykinase, a key enzyme for intracellular survival, showing that lactate utilization requires essential metabolic pathways. We observed that the ΔlldD2 mutant was impaired in replication in human macrophages, indicating a critical role for lactate oxidation during intracellular growth.

Serum lactate is an independent predictor of hospital mortality in critically ill patients in the emergency department: a retrospective study

Background

Elevated lactate has been found to be associated with a higher mortality in a diverse patient population. The aim of the study is to investigate if initial serum lactate level is independently associated with hospital mortality for critically ill patients presenting to the Emergency Department.

Methods

Single-center, retrospective study at a tertiary care hospital looking at patients who presented to the Emergency Department (ED) between 2014 and 2016. A total of 450 patients were included in the study. Patients were stratified to lactate levels: <2 mmol/L, 2-4 mmol/L and >4 mmol/L. The primary outcome was in-hospital mortality. Secondary outcomes included 72-h hospital mortality, ED and hospital lengths of stay.

Results

The mean age was 64.87 ± 18.08 years in the <2 mmol/L group, 68.51 ± 18.01 years in the 2-4 mmol/L group, and 67.46 ± 17.67 years in the >4 mmol/L group. All 3 groups were comparable in terms of age, gender and comorbidities except for diabetes, with the 2-4 mmol/L and >4 mmol/L groups having a higher proportion of diabetic patients. The mean lactate level was 1.42 ± 0.38 (<2 mmol/L), 2.72 ± 0.55 (2-4 mmol/L) and 7.18 ± 3.42 (>4 mmol/L). In-hospital mortality was found to be 4 (2.7%), 18(12%) and 61(40.7%) patients in the low, intermediate and high lactate groups respectively. ED and hospital length of stay were longer for the >4 mmol/L group as compared to the other groups. While adjusting for all variables, patients with intermediate and high lactate had 7.13 (CI 95% 2.22–22.87 p = 0.001) and 29.48 (CI 95% 9.75–89.07 p = <0.001) greater odds of in-hospital mortality respectively.

Discussion

Our results showed that for all patients presenting to the ED, a rising lactate value is associated with a higher mortality. This pattern was similar regardless of patients’ age, presence of infection or blood pressure at presentation.

Conclusion

Higher lactate values are associated with higher hospital mortalities and longer ED and hospital lengths of stays. Initial ED lactate is a useful test to risk-stratify critically ill patients presenting to the ED.

Resuscitation in hip fractures: a systematic review

To evaluate the evidence for the resuscitation of patients with hip fracture in the preoperative or perioperative phase of their treatment and its impact on mortality.

DESIGN

We searched MEDLINE, EMBASE, CENTRAL and PROSPERO databases using a systematic search strategy for randomised trials and observational studies investigating the fluid resuscitation of any patient with hip fracture. No language limits were applied to the search, which was complemented by manually screening the reference lists of appropriate studies.

OUTCOME MEASURES

Mortality at 1 week, 30 days and 1 year following surgery.

RESULTS

Two hundred and ninety-eight citations were identified, and 12 full manuscripts were reviewed; no studies satisfied the inclusion criteria. The background literature showed that the mortality for these patients at 30 days is approximately 8.5% and that bone cement implantation syndrome is insufficient to explain this. The literature was explored to define the need for an interventional investigation into the preoperative resuscitation of patients with hip fracture.

CONCLUSIONS

Patients with hip fracture show similar physiological disturbance to major trauma patients. Nineteen per cent of patients presenting with hip fracture are hypoperfused and 50% show preoperative anaemia suggesting that under resuscitation is a common problem that has not been investigated. A properly conducted interventional trial could improve the outcome of these vulnerable patients.

Serum Lactate Predicts Adverse Outcomes in Emergency Department Patients With and Without Infection

INTRODUCTION

Lactate levels are increasingly used to risk stratify emergency department (ED) patients with and without infection. Whether a serum lactate provides similar prognostic value across diseases is not fully elucidated. This study assesses the prognostic value of serum lactate in ED patients with and without infection to both report and compare relative predictive value across etiologies.

METHODS

We conducted a prospective, observational study of ED patients displaying abnormal vital signs (AVS) (heart rate ≥130 bpm, respiratory rate ≥24 bpm, shock index ≥1, and/or systolic blood pressure <90 mmHg). The primary outcome, deterioration, was a composite of acute renal failure, non-elective intubation, vasopressor administration or in-hospital mortality.

RESULTS

Of the 1,152 patients with AVS who were screened, 488 patients met the current study criteria: 34% deteriorated and 12.5% died. The deterioration rate was 88/342 (26%, 95% CI: 21 - 30%) for lactate < 2.5 mmol/L, 47/90 (52%, 42 - 63%) for lactate 2.5 - 4.0 mmol/L, and 33/46 (72%, 59 - 85%) for lactate >4.0mmol/L. Trended stratified lactate levels were associated with deterioration for both infected (p<0.01) and non-infected (p<0.01) patients. In the logistic regression models, lactate > 4mmol/L was an independent predictor of deterioration for patients with infection (OR 4.8, 95% CI: 1.7 - 14.1) and without infection (OR 4.4, 1.7 - 11.5).

CONCLUSION

Lactate levels can risk stratify patients with AVS who have increased risk of adverse outcomes regardless of infection status.

Role of suPAR and Lactic Acid in Diagnosing Sepsis and Predicting Mortality in Elderly Patients

This study investigated the diagnostic value of soluble urokinase plasminogen activator receptor (suPAR) and serum lactate in elderly patients with sepsis and evaluated their capacity to predict mortality and their correlation to Sequential Organ Failure Assessment (SOFA) score. The study included 80 participants, divided into two groups: 40 cases (mean age, 68.9 ± 5.9) admitted to the intensive care unit and 40 healthy controls (mean age, 67.1 ± 6.2). Elderly patients with sepsis had significantly higher levels of serum suPAR and lactic acid compared to healthy controls. Receiver operating characteristic (ROC) curve analysis showed that suPAR (cutoff value, ≥4.37 ng/ml) has higher area under the curve (AUC) than lactic acid (cutoff value, ≥1.95 mmol/l) for diagnosing sepsis. Serum lactate has superior prognostic value compared to suPAR with AUC of 0.82 (cutoff value, 2.2 mmol/l) and 0.72 (cutoff value, 6.3 ng/ml), respectively. The diagnostic power of combined usage of suPAR and lactate serum concentrations showed AUC of 0.988 (95% confidence interval 0.934 to 1.0). The combination of both biomarkers either together or with SOFA score may serve as a useful guide to patients who need more intensive resuscitation.