Does lactate measurement performed on admission predict clinical outcome on the intensive care unit? A concise systematic review

Value of modified qSOFA, glucose and lactate in predicting prognosis in children with sepsis in the PICU

The purpose was to investigate how well age-adjusted modified quick Sequential Organ Failure Assessment (qSOFA) scores paired with blood glucose and lactate levels predict the outcomes of septicemic children in the pediatric intensive care unit (PICU). One hundred children who were diagnosed with sepsis and septic shock in the PICU of Henan Children's Hospital were eligible, and other 20 patients in the same hospital at different times were selected as a validation set. Respiratory rate (RR), heart rate (HR), capillary refill time (CRT), and Alert, Voice, Pain, Unresponsive (AVPU) scale were included in the age-adjusted modified qSOFA scoring criteria for scoring. The primary outcome was 28-day all-cause mortality. The predictive values were evaluated by the ROC curve. In the sepsis group, 50 patients were male, and 50 patients were female. The 28-day all-cause mortality rate was 52%. Fifty-one patients with age-adjusted modified qSOFA scores >1. The serum lactate level was 2.4 mmol/L, and the blood glucose level was 9.3 mmol/L. The AUCs for the age-adjusted modified qSOFA score, serum lactate and blood glucose levels for the prediction of 28-day all-cause mortality in children with sepsis were 0.719, 0.719 and 0.737, respectively. The cut-off values were one point, 3.8 mmol/L and 10 mmol/L, respectively. The AUC of the age-adjusted modified qSOFA score for the validation set of was 0.925. When the three indices were combined, the AUC was 0.817, the Hosmer-Lemeshow goodness-of-fit test showed χ2 = 2.428 and p = .965. When children with sepsis are admitted to the ICU, we recommend performing rapid scoring and rapid bedside lactate and glucose testing to determine the early prognosis.

Heart/breathing rate ratio (HBR) as a predictor of mortality in critically ill patients

Objectives

The early prediction of death is a challenge for medical staff. We evaluated the ability of the heart/breathing rate ratio (HBR) to predict mortality.

Methods

This was a single-center retrospective observational study of adult patients who had fever with or without respiratory symptoms, who survived at least 2 h after visiting the hospital, and whose lactate levels and vital signs were tested. We evaluated the distribution of mortality at different HBR levels and compared HBR with lactate.

Results

A total of 18,872 fever clinic visits were screened, and 183 patients whose lactate levels were tested were recruited. Patients who had HBR values lower than 4·5 or higher than 5·5 had greater mortality than patients who had HBR values between 4·5 and 5·5 (21·3 % vs. 3·4 %, p = 0·003; 28·9 % vs. 3·4 %, p < 0·001, respectively). In patients whose HBR was <5, the AUROC for HBR for mortality was 0·762 (95 % CI: 0.643-0·880), and that for lactate was 0·701 (95 % CI: 0·564-0·837). In patients whose HBR was ≥5, the AUROC for HBR for mortality was 0·721 (95 % CI: 0·584-0·857), and that for lactate was 0·742 (95 % CI: 0·607-0·848).

Conclusions

HBR is helpful for stratifying mortality risk among critically ill patients in acute care clinics for infectious diseases.

Clinical course and outcomes of cancer patients admitted in medical ICU with sepsis

Background and aims

Sepsis is not only a leading cause of intensive care unit (ICU) admission but also one of the variables which affect outcomes of cancer patients. We aimed to assess the clinical characteristics, clinical course, mortality and risk factors associated with 30-day mortality in medical oncology patients admitted in a multi-disciplinary medical ICU.

Methods

We conducted a retrospective analysis of 435 consecutive cancer patients admitted in medical ICU over a 28 months period. Patients were divided into two groups based on the presence of sepsis at the time of ICU admission. Data regarding baseline patient characteristics, clinical and laboratory data, need for organ support and 30-day mortality were collected. Sepsis patients were further classified as 30-day survivors and non-survivors and risk factors for mortality in these patients were determined.

Results

Overall 30-day mortality was 57.8%. It was significantly higher in sepsis group patients (73.9%) as compared to non-sepsis patients (46.6%) (p < 0.001). Most common reason for ICU admission in non-sepsis group was respiratory distress (51.4%) followed by altered sensorium (28.4%). Presence of metastasis [odds ratio, OR: 3.89 (95% confidence interval, CI: 1.536-9.901)], high lactate [OR: 1.374 (95% CI: 1.024-1.843)] and need of invasive mechanical ventilator (IMV) support [OR: 7.634 (95% CI: 2.519-23.256)] or vasopressor support [OR: 3.268 (95% CI: 1.179-9.090)] were directly associated with 30-day mortality.

Conclusion

Critically ill cancer patients admitted with sepsis had high mortality. Presence of metastasis, high lactate and need of IMV or vasopressor support was associated with worse prognosis in cancer patients admitted with sepsis in ICU.

Emerging concepts in the care of patients with cirrhosis and septic shock

Septic shock impacts approximately 6% of hospitalized patients with cirrhosis and is associated with high rates of morbidity and mortality. Although a number of landmark clinical trials have paved the way for incremental improvements in the diagnosis and management of septic shock in the general population, patients with cirrhosis have largely been excluded from these studies and critical knowledge gaps continue to impact the care of these individuals. In this review, we discuss nuances in the care of patients with cirrhosis and septic shock using a pathophysiology-based approach. We illustrate that septic shock may be challenging to diagnose in this population in the context of factors such as chronic hypotension, impaired lactate metabolism, and concomitant hepatic encephalopathy. Furthermore, we demonstrate that the application of routine interventions such as intravenous fluids, vasopressors, antibiotics, and steroids should be carefully considered among those with decompensated cirrhosis in light of hemodynamic, metabolic, hormonal, and immunologic disturbances. We propose that future research should include and characterize patients with cirrhosis in a systematic manner, and clinical practice guidelines may need to be refined accordingly.

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

BACKGROUND

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

OBJECTIVES

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

DESIGN AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Risk Factors for Mortality in Sepsis Patients without Lactate Levels Increasing Early

Objectives

Our purpose was to investigate the influencing factors for mortality in sepsis patients without lactate levels increasing in the early stage.

Methods

We conducted a retrospective observational study involving 830 adult sepsis patients admitted to ICU. We calculated time-weighted lactate (LacTW), a dynamic value that incorporates both the magnitude of change and the time interval of such change, to represent lactate levels in the first 24 hours. ROC curve was used to find the cutoff of LacTW for predicting mortality, and the influencing factors for lactate levels and mortality in the low lactate group were further studied. The primary outcome was hospital mortality.

Results

Among 830 patients, LacTW > 1.975 mmo/L was found to be the cutoff threshold for predicting mortality (AUC = 0.646, P < 0.001). The following indexes related to organ dysfunction influenced LacTW: acute physiology and chronic health evaluation II (APACHE II) score (P < 0.001), activated partial thromboplastin time (APTT) (P = 0.002), total bilirubin (P = 0.012), creatinine (P = 0.037), with hypotension (P < 0.001), chronic kidney disease (P = 0.013), and required continuous renal replacement therapy (CRRT) (P < 0.001). Of the 394 patients in the low lactate group, age (P = 0.002), malignancy (P < 0.001), lactate dehydrogenase (P = 0.006), required treatment such as mechanical ventilation (P < 0.001), CRRT (P < 0.001), vasoactive drugs (P < 0.001), and glucocorticoid (P < 0.001), and failure to reach the target fluid resuscitation of 30 ml/kg within 6 hours (P = 0.003) were independently associated with hospital mortality.

Conclusions

Due to the lower incidence of early organ dysfunction, lactate levels are not increased or delayed in some septic shock patients in the early stage, thus affecting the alertness of clinicians and the timeliness and adequacy of fluid resuscitation, and finally affects the prognosis.

New Strategies to Optimize Hemodynamics for Sepsis-Associated Encephalopathy

Background: Sepsis-associated encephalopathy (SAE) is associated with high morbidity and mortality. Hemodynamic dysfunction plays a significant role in the incidence and mortality of SAE. Therefore, this study aimed to explore the relationship between hemodynamic indicators and SAE. Methods: 9033 patients with sepsis 3.0 were selected in a prospective study cohort. The LASSO regression model was used to select characteristic variables and remove the collinearity between them. In addition, a generalized additive model was used to find the optimal hemodynamic index value for patients with SAE. Multivariate logistic regression models, propensity matching scores, inverse probability weighting, and doubly robust estimation confirmed the reliability of the study results (i.e., the optimal hemodynamic indicators targeting patients with SAE). Results: A mean arterial pressure ≥ 65 mmHg, systolic blood pressure ≥ 90 mmHg, and lactate levels ≤ 3.5 mmol/L decrease the incidence of SAE, whereas a mean arterial pressure ≥ 59 mmHg and lactate levels ≤ 4.5 mmol/L decrease the 28-day mortality in patients with SAE. Conclusions: The hemodynamic indices of patients with SAE should be maintained at certain levels to reduce the incidence and mortality in patients with SAE, such that the mean arterial pressure is ≥65 mmHg, lactate levels are ≤3.5 mmol/L, and systolic blood pressure is ≥90 mmHg. These hemodynamic indicators should be targeted in patients with SAE.

The supplementation of L-carnitine in septic shock patients: Systematic review and meta-analysis

BACKGROUND

Sepsis and septic shock are severe and difficult-to-treat conditions with high lethality. There is interest in identifying new adjunct therapies that are effective in reducing mortality. In this context, L-carnitine has been investigated in trials as a potentially beneficial drug. Therefore, the aim of this systematic review was to assess the clinical evidence to support the use of L-carnitine in septic shock patients to reduce the risk of mortality. The objective of this review was to evaluate the effect of L-carnitine compared to placebo or Usual Care (UC) on the mortality rate in hospitalized adult septic shock patients.

METHODS

The authors exclusively included randomized clinical trials that compared the use of L-carnitine versus placebo in adult (> 18 years old) septic shock patients. The outcome was a mortality rate of 28 days. This systematic review and meta-analysis were performed following the PRISMA guidelines and registered in PROSPERO with the ID CRD42020180499.

RESULTS

Following the initial search, 4007 citations were identified, with 2701 remaining after duplicate removal. Eight citations were selected for body text reading, and two were selected for inclusion. The studies enrolled 275 patients, with 186 in the carnitine arm and 89 in the placebo arm. The effect of L-carnitine uses in septic shock patients showed a difference risk of -0.03 (95% Confidence Interval: -0.15-0.10, I² = 77%, p = 0.69) compared to placebo/in mortality rate with low quality of evidence.

CONCLUSIONS

There is low-quality evidence that the use of L-carnitine has no significant effect on reducing 28-day mortality in septic shock patients.

Predictive Value of Point-of-care Lactate Measurement in Patients Meeting Level II and III Trauma Team Activation Criteria that Present to the Emergency Department: A Prospective Study

Background

The aim of this study was to investigate the utility of early point-of-care (POC) lactate levels to help predict injury severity and ultimate emergency department (ED) disposition for trauma patients meeting Level II and III activation criteria.

Methods

This was a blinded, prospective cohort study including a convenience sample of patients meeting our triage criteria for Level II or III team activation with stable vital signs. Bedside lactate samples were collected during the secondary survey. Clinical care/disposition was at the discretion of physicians who remained blinded to the bedside lactate result. An elevated lactate was defined as >2.0 mmol/L.

Results

Ninety-six patients were in the study group; mean age was 41 ± 17 years, 26% were female, 57% were Hispanic, and 60% admitted. We found no difference in initial mean POC lactate levels (mmol/L) for admitted versus discharged groups and Injury Severity Score (ISS) ≥9 versus ISS <9 groups (3.71 [95% confidence interval (CI): 3.1-4.4] vs. 3.85 [95% CI: 2.8-4.9]; P = 0.99 and 3.54 [95% CI: 2.7-4.4] vs. 3.89 [95% CI: 3.1-4.6]; P = 0.60, respectively). Performance characteristics of early elevated lactate levels were poor both to predict need for hospital admission (sensitivity = 77% [65%-87%]; specificity = 26% [13%-43%]; negative predictive value [NPV] = 43% [27%-61%]; and positive predictive value [PPV] = 62% [56%-67%]) and to identify patients with ISS scores ≥9 (sensitivity = 76% [59%-89%]; specificity = 24% [14%-37%]; NPV = 65% [47%-80%]; and PPV = 36% [30%-41%]).

Conclusions

For Level II/III, we found that early bedside lactate levels were not predictive of ISS ≥9 or the need for admission.

Level of Evidence

III (diagnostic test).

Measurement of a Novel Biomarker, Secretory Phospholipase A2 Group IIA as a Marker of Sepsis: A Pilot Study

Introduction:

Early identification of sepsis is critical as early treatment improves outcomes. We sought to identify threshold values of secretory phospholipase A2 (sPLA2)-IIA that predict sepsis and bacterial infection compared to nonseptic controls in an emergency department (ED) population.

Materials and Methods:

This is a prospective cohort of consenting adult patients who met two or more systemic inflammatory response syndrome (SIRS) criteria with clinical diagnosis of infectious source likely (septic patients). Controls were nonseptic consenting adults undergoing blood draw for other ED indications. Both groups had blood drawn, blind-coded, and sent to an outside laboratory for quantitative analysis of sPLA2-IIA levels. The study investigators reviewed patients’ inpatient medical record for laboratory, imaging, and microbiology results, as well as clinical course.

Results:

sPLA2-IIA levels were significantly lower in control patients as compared to septic patients (median = 0 ng/ml [interquartile range (IQR): 0–6.5] versus median = 123 ng/ml [IQR 44–507.75]; P < 0.0001). SPLA2-IIA levels were higher in patients with confirmed source (n = 28 patients, median = 186 ng/ml, 95% confidence interval = 115.1–516.8) as compared to those with no source identified or a viral source (n = 17, median = 68 ng/ml, 95% confidence interval = 38.1–122.7; P = 0.04). Using a cutoff value of 25 ng/ml, sPLA2-IIA had a sensitivity of 86.7% (confidence interval 72.5–94.5) and a specificity of 91.1% (confidence interval 77.9–97.1) in detecting sepsis.

Conclusions:

sPLA2-IIA shows potential as a biomarker distinguishing sepsis from other disease entities. Further study is warranted to identify predictive value of trends in sPLA-IIA during disease course in septic patients.

Independent early predictors of mortality in polytrauma patients: a prospective, observational, longitudinal study

OBJECTIVES:

Trauma is an important public health issue and associated with substantial socioeconomic impacts and major adverse clinical outcomes. No single study has previously investigated the predictors of mortality across all stages of care (pre-hospital, emergency room, surgical center and intensive care unit) in a general trauma population. This study was designed to identify early predictors of mortality in severely injured polytrauma patients across all stages of care to provide a better understanding of the physiologic changes and mechanisms by which to improve care in this population.

METHODS:

A longitudinal, prospective, observational study was conducted between 2010 and 2013 in São Paulo, Brazil. Patients submitted to high-energy trauma were included. Exclusion criteria were as follows: injury severity score <16, <18 years old or insufficient data. Clinical and laboratory data were collected at four time points: pre-hospital, emergency room, and 3 and 24 hours after hospital admission. The primary outcome assessed was mortality within 30 days. Data were analyzed using tests of association as appropriate, nonparametric analysis of variance and generalized estimating equation analysis (p<0.05). ClinicalTrials.gov: NCT01669577.

RESULTS:

Two hundred patients were included. Independent early predictors of mortality were as follows: arterial hemoglobin oxygen saturation (p<0.001), diastolic blood pressure (p<0.001), lactate level (p<0.001), Glasgow Coma Scale score (p<0.001), infused crystalloid volume (p<0.015) and presence of traumatic brain injury (p<0.001).

CONCLUSION:

Our results suggest that arterial hemoglobin oxygen saturation, diastolic blood pressure, lactate level, Glasgow Coma Scale, infused crystalloid volume and presence of traumatic brain injury are independent early mortality predictors.

Clinical significance of dynamic monitoring of blood lactic acid, oxygenation index and C-reactive protein levels in patients with severe pneumonia

The aim of the present study was to analyze the clinical significance of the dynamic monitoring of blood lactic acid levels, the oxygenation index and C-reactive protein (CRP) levels in patients with severe pneumonia. The clinical data of 34 cases with severe pneumonia were collected. According to the clinical outcome, the patients were divided into a survival group (n=26) and a fatality group (n=8). Various factors, including the blood lactic acid level, oxygenation index, CRP level and acute physiology and chronic health evaluation II (APACHE II) score, were retrospectively analyzed in order to investigate whether these values had clinical significance for the prognosis of the patients. No statistically significant differences with regard to age, gender, initial concentrations of blood lactic acid and CRP, and APACHE II scores were observed between the two groups at admission to the Intensive Care Unit. However, the blood lactic acid levels were found to decrease to a normal level within 12-24 h after treatment in the survival group, while the levels were maintained at a higher concentration in the fatality group, even at 72 h after treatment (P<0.05). Furthermore, the oxygenation index in the survival group was significantly higher when compared with that in the fatality group. The oxygenation index was maintained at a normal level in the survival group, while the oxygenation index levels were below normal and continued to decline in the fatality group. A positive correlation was observed between the blood lactic acid level and the APACHE II scores (r=0.656, P<0.05). Therefore, the present study demonstrated that dynamic monitoring of blood lactic acid, oxygenation index and CRP levels in patients with severe pneumonia can be used to evaluate the therapeutic efficiency, in addition to serving as a prognosis indicator, for patients with severe pneumonia.

Novel relationships between oxidative stress and angiogenesis-related factors in sepsis: New biomarkers and therapies

Sepsis is a systemic uncontrolled inflammatory response in the presence of an infection. It remains a major cause of morbidity and mortality in hospitalized patients. According to its severity, sepsis can progress to three different states: severe sepsis, septic shock, and multiple organ dysfunction syndrome, related to organ dysfunction and/or tissue hypoperfusion. Different processes underlie its pathophysiology; among them are oxidative stress, endothelial and mitochondrial dysfunction, and angiogenesis-related factors. However, no studies have integrated these elements in sepsis. The main difficulty in sepsis is its diagnosis. Currently, the potential of inflammatory biomarkers in septic patients remains weak. In this context, the research into new biomarkers is essential to aid with sepsis diagnosis and prognostication. Furthermore, even though the current management of severe forms of sepsis has been effective, morbimortality remains elevated. Therefore, it is essential to explore alternative approaches to therapy development. The aim of this review is to present an update of evidence supporting the role of oxidative stress and angiogenesis-related factors in the pathophysiology of the different forms of sepsis. It proposes a novel convergence between both elements in their role in the disease, and it will cover their utility as new diagnostic tools, predictors of outcome, and as novel therapeutic targets.

Point of care blood gases with electrolytes and lactates in adult emergencies

Point-of-care testing (POCT) is one of the formidable concept introduce in the field of critical care settings to deliver decentralized, patient-centric health care to the patients. Rapid provision of blood measurements, particularly blood gases and electrolytes, may translate into improved clinical outcomes. Studies shows that POCT carries advantages of providing reduced therapeutic turnaround time (TTAT), shorter door-to-clinical-decision time, rapid data availability, reduced preanalytic and postanalytic testing errors, self-contained user-friendly instruments, small sample volume requirements, and frequent serial whole-blood testing. However, still there is a noticeable debate that exists among the laboratorians, clinicians, and administrators over concerns regarding analyzer inaccuracy, imprecision and performance (interfering substances), poorly trained non-laboratorians, high cost of tests, operator-dependent quality of testing, and difficulty in integrating test results with hospital information system (HIS). On search of literature using Medline/Pubmed and Embase using the key phrases "ppoint-of-care test," "central laboratory testing," "electrolytes," "blood gas analysis," "lactate," "emergency department," "intensive care unit," we found that POCT of blood gases and selected electrolytes may not entirely replace centralized laboratory testing but may transfigure the clinical practice paradigm of emergency and critical care physicians. We infer that further comprehensive, meaningful and rigorous evaluations are required to determine outcomes which are more quantifiable, closely related to testing events and are associated with effective cost benefits.

Predictive value of lactate in unselected critically ill patients: an analysis using fractional polynomials

BACKGROUND AND OBJECTIVES

Hyperlactatemia has long been associated with poor clinical outcome in varieties of intensive care unit (ICU) patients. However, the impact of temporal changes in lactate has not been well established and there are some shortcomings in model building in previous studies. The present study aims to investigate the association of initial lactate and normalization time with hazard by using fractional polynomial Cox proportional hazard model.

METHODS

A large clinical database named Multiparameter Intelligent Monitoring in Intensive Care II (MIMIC-II) was employed for analysis. Demographics, comorbidities, laboratory findings were extracted and were compared between survivors and non-survivors by using univariable analysis. Cox proportional hazard model was built by purposeful selection of covariate with initial lactate (L0) and normalization time (T) remaining in the model. Best fit model was selected by using deviance difference test and comparisons between fractional polynomial regression models of different degrees were performed by using closed test procedure.

MAIN RESULTS

A total of 6,291 ICU patients were identified to be eligible for the present study, including 1,675 non-survivors and 4,616 survivors (mortality rate: 26.6%). Patients with lactate normalization had significantly reduced hazard rate as compared to those without normalization (log-rank test: P<0.05). The best powers of L0 in the model were -2 and -1 with the deviance of 19,944.51, and the best powers of T were 0.5 and 3 with the deviance of 7,965.63. The adjusted hazard ratio for the terms L0(-2) and L0(-1) were 1.13 (95% CI: 1.09-1.18) and 0.43 (95% CI: 0.34-0.54); and the adjusted hazard ratio for the terms T(0.5) and T(3) were 7.42 (95% CI: 2.85-19.36) and 3.06×10(-6) (95% CI: 3.01×10(-11)-0.31).

CONCLUSIONS

Initial lactate on ICU admission is associated with death hazard and the relationship follows a fractional polynomial pattern with the power of -2 and -1. Delayed normalization of lactate is predictive of high risk of death when it is measured within 150 hours after ICU admission.

Biomarkers for sepsis: a review with special attention to India

Sepsis is a serious infection and still a common cause of morbidity and mortality in resource-limited settings such as India. Even when microbiologic diagnostics are available, bacteremia is only identified in a proportion of patients who present with sepsis and bloodstream infections. Biomarkers have been used in a variety of disease processes and can help aid in diagnosing bacterial infections. There have been numerous biomarkers investigated to aid with diagnosis and prognostication in sepsis with the majority suffering from lack of sensitivity or specificity. Procalcitonin has been heralded as the biomarker that holds the most promise for bloodstream infections. Data are emerging in India, and in this review, we focus on the current data of biomarkers in sepsis with particular attention to how biomarkers could be used to augment diagnosis and treatment in India.

Serum metabolomics identifies citrulline as a predictor of adverse outcomes in an equine model of gut-derived sepsis

Acute laminitis is an inflammatory disease of the equine foot that often occurs secondarily to sepsis or systemic inflammation associated with gastrointestinal disease. It has been suggested that laminitis is similar to multiple organ dysfunction syndrome in humans, although in horses the weight-bearing laminar epithelium of the foot appears to be the tissue most sensitive to insult and the first "organ" to fail. Metabolomics performed on serum samples collected before (Con) and after (Lmn) experimental induction of gastrointestinal-associated sepsis in six horses detected 1,177 metabolites of both mammalian and bacterial origin in equine serum. Network and correlation analyses suggested a dysregulation of fatty acid metabolism in the Lmn group, as well as an accumulation of organic acids such as lactate. Furthermore, concentrations of the amino acid citrulline were decreased in Lmn samples from all study animals, suggesting that citrulline might be useful as a biomarker to identify critically ill animals that are at risk of developing laminitis. We therefore established normal ranges of plasma citrulline concentrations in a separate group of horses (n = 36) and tested the ability of citrulline to predict adverse outcomes (laminitis or death) in critically ill horses (n = 23). Plasma citrulline was significantly lower in critically ill horses that went on to experience adverse outcomes (n = 6). Further study is required to accurately determine a diagnostic cutoff, but the present data are suggestive of the predictive value of citrulline as a biomarker for laminar failure in equine sepsis.

Untargeted LC-MS metabolomics of bronchoalveolar lavage fluid differentiates acute respiratory distress syndrome from health

Acute respiratory distress syndrome (ARDS) remains a significant hazard to human health and is clinically challenging because there are no prognostic biomarkers and no effective pharmacotherapy. The lung compartment metabolome may detail the status of the local environment that could be useful in ARDS biomarker discovery and the identification of drug target opportunities. However, neither the utility of bronchoalveolar lavage fluid (BALF) as a biofluid for metabolomics nor the optimal analytical platform for metabolite identification is established. To address this, we undertook a study to compare metabolites in BALF samples from patients with ARDS and healthy controls using a newly developed liquid chromatography (LC)-mass spectroscopy (MS) platform for untargeted metabolomics. Following initial testing of three different high-performance liquid chromatography (HPLC) columns, we determined that reversed phase (RP)-LC and hydrophilic interaction chromatography (HILIC) were the most informative chromatographic methods because they yielded the most and highest quality data. Following confirmation of metabolite identification, statistical analysis resulted in 37 differentiating metabolites in the BALF of ARDS compared with health across both analytical platforms. Pathway analysis revealed networks associated with amino acid metabolism, glycolysis and gluconeogenesis, fatty acid biosynthesis, phospholipids, and purine metabolism in the ARDS BALF. The complementary analytical platforms of RPLC and HILIC-LC generated informative, insightful metabolomics data of the ARDS lung environment.

Blood lactate concentration after exposure to conducted energy weapons (including TASER® devices): is it clinically relevant?

In previous studies, blood lactate concentration (BLac) consistently increased in anesthetized animals and in human subjects after exposures to TASER(®) conducted energy weapons (CEWs). Some have suggested the increased BLac would have detrimental consequences. In the current review, the following are evaluated: (a) the nature of muscle contractions due to CEWs, (b) general aspects of increased BLac, (c) previous studies of conventional neuromuscular electrical stimulation and CEW exposures, and (d) BLac in disease states. On the basis of these analyses, one can conclude that BLac, per se (independent of acidemia), would not be clinically relevant immediately after short-duration CEW applications, due to the short time course of any increase.