Clinical use of plasma lactate concentration. Part 1: Physiology, pathophysiology, and measurement

Continuous and Non-Invasive Lactate Monitoring Techniques in Critical Care Patients

Lactate, once merely regarded as an indicator of tissue hypoxia and muscular fatigue, has now gained prominence as a pivotal biomarker across various medical disciplines. Recent research has unveiled its critical role as a high-value prognostic marker in critical care medicine. The current practice of lactate detection involves periodic blood sampling. This approach is invasive and confined to measurements at six-hour intervals, leading to resource expenditure, time consumption, and patient discomfort. This review addresses non-invasive sensors that enable continuous monitoring of lactate in critical care patients. After the introduction, it discusses the iontophoresis system, followed by a description of the structural materials that are universally employed to create an interface between the integumentary system and the sensor. Subsequently, each method is detailed according to its physical principle, outlining its advantages, limitations, and pertinent aspects. The study concludes with a discussion and conclusions, aiming at the design of an intelligent sensor (Internet of Medical Things or IoMT) to facilitate continuous lactate monitoring and enhance the clinical decision-making support system in critical care medicine.

Capturing wild animal welfare: a physiological perspective

Affective states, such as emotions, are presumably widespread across the animal kingdom because of the adaptive advantages they are supposed to confer. However, the study of the affective states of animals has thus far been largely restricted to enhancing the welfare of animals managed by humans in non-natural contexts. Given the diversity of wild animals and the variable conditions they can experience, extending studies on animal affective states to the natural conditions that most animals experience will allow us to broaden and deepen our general understanding of animal welfare. Yet, this same diversity makes examining animal welfare in the wild highly challenging. There is therefore a need for unifying theoretical frameworks and methodological approaches that can guide researchers keen to engage in this promising research area. The aim of this article is to help advance this important research area by highlighting the central relationship between physiology and animal welfare and rectify its apparent oversight, as revealed by the current scientific literature on wild animals. Moreover, this article emphasises the advantages of including physiological markers to assess animal welfare in the wild (e.g. objectivity, comparability, condition range, temporality), as well as their concomitant limitations (e.g. only access to peripheral physiological markers with complex relationships with affective states). Best-practice recommendations (e.g. replication and multifactorial approaches) are also provided to allow physiological markers to be used most effectively and appropriately when assessing the welfare of animals in their natural habitat. This review seeks to provide the foundation for a new and distinct research area with a vast theoretical and applied potential: wild animal welfare physiology.

Metabolomic profiling of human bladder tissue extracts

INTRODUCTION

Bladder cancer is a common malignancy affecting the urinary tract and effective biomarkers and for which monitoring therapeutic interventions have yet to be identified.

OBJECTIVES

Major aim of this work was to perform metabolomic profiling of human bladder cancer and adjacent normal tissue and to evaluate cancer biomarkers.

METHODS

This study utilized nuclear magnetic resonance (NMR) and high-resolution nanoparticle-based laser desorption/ionization mass spectrometry (LDI-MS) methods to investigate polar metabolite profiles in tissue samples from 99 bladder cancer patients.

RESULTS

Through NMR spectroscopy, six tissue metabolites were identified and quantified as potential indicators of bladder cancer, while LDI-MS allowed detection of 34 compounds which distinguished cancer tissue samples from adjacent normal tissue. Thirteen characteristic tissue metabolites were also found to differentiate bladder cancer tumor grades and thirteen metabolites were correlated with tumor stages. Receiver-operating characteristics analysis showed high predictive power for all three types of metabolomics data, with area under the curve (AUC) values greater than 0.853.

CONCLUSION

To date, this is the first study in which bladder human normal tissues adjacent to cancerous tissues are analyzed using both NMR and MS method. These findings suggest that the metabolite markers identified in this study may be useful for the detection and monitoring of bladder cancer stages and grades.

Establishment of a reference interval for thiamine concentrations in healthy dogs and evaluation of the prevalence of absolute thiamine deficiency in critically ill dogs with and without sepsis using high-performance liquid chromatography

OBJECTIVE

To determine the normal reference interval (RI) for thiamine concentrations in healthy dogs and investigate the prevalence of thiamine deficiency in critically ill dogs with and without sepsis.

DESIGN

Prospective, observational, multicenter study, conducted between 2019 and 2021.

SETTING

Two veterinary university teaching hospitals.

ANIMALS

A total of 109 dogs were enrolled into 3 groups: 40 healthy dogs, 33 dogs with suspected or confirmed sepsis and evidence of tissue hypoperfusion (Doppler blood pressure ≤90 mm Hg or plasma lactate ≥3 mmol/L), and 36 dogs with other critical illnesses and evidence of tissue hypoperfusion.

INTERVENTIONS

For each dog, CBC, serum biochemistry, plasma lactate concentration, whole-blood thiamine concentration, blood pressure, vital parameters, Acute Patient Physiologic and Laboratory Evaluation (APPLE)fast score, and clinical outcomes were recorded, alongside basic patient parameters and dietary history. Whole-blood thiamine pyrophosphate (TPP) concentrations were measured using high-performance liquid chromatography.

MEASUREMENTS AND MAIN RESULTS

The RI for whole-blood TPP in healthy dogs was 70.9-135.3 μg/L. Median TPP concentrations were significantly lower in septic dogs compared to healthy controls (P = 0.036). No significant difference in median TPP concentrations was found between septic dogs and nonseptic critically ill dogs, or between healthy dogs and nonseptic critically ill dogs. TPP concentrations were below the normal RI in 27.3% of septic dogs, compared to 19.4% of nonseptic critically ill dogs (P = 0.57). No correlations were found between TPP concentrations and lactate concentrations, age, body condition scores, time since last meal, RBC count, serum alanine aminotransferase, APPLEfast scores, or patient outcomes.

CONCLUSIONS

TPP concentrations were significantly lower in septic dogs compared to healthy controls, with an absolute thiamine deficiency found in 27.3% of septic dogs. The established TPP RI allows for further investigation of thiamine deficiency in critically ill dogs.

Ultrasonographic measurement of caudal vena cava to aorta ratio during fluid resuscitation of dogs with spontaneous circulatory shock

OBJECTIVES

To describe the change in the caudal vena cava to aorta ratio (CVC:Ao) ratio during fluid resuscitation of circulatory shock in dogs and compare these results with those of the physical examination and blood lactate.

MATERIALS AND METHODS

Perfusion parameters and blood lactate were recorded at admission. An abdominal point-of-care ultrasound protocol was performed, during which the caudal vena cava to aorta ratio was measured on the spleno-renal view. Measurements were performed within 5 minutes before and after a 10 mL/kg crystalloid fluid bolus. Investigators were not blinded to therapeutic interventions.

RESULTS

Twenty-nine dogs with physical signs of circulatory shock were enrolled. Caudal vena cava to aorta ratios were below reference interval in 28 of 29 dogs. After bolus administration, median caudal vena cava diameter increased by 0.14 cm (0.69 to 0.83 cm) and median aorta diameter increased by 0.03 cm (0.87 to 0.90 cm) and caudal vena cava to aorta ratio returned to within reference range in 65% of dogs (13/29). Bolus administration was associated with an increase in median caudal vena cava to aorta ratio of 0.10 (95% CI:0.05 to 0.16, P=0.0005). Blood lactate did not change significantly. Heart rate and capillary refill time decreased significantly after fluid bolus (heart rate: estimate=-19 bpm, 95% CI:-30 to -8, P=0.002; capillary refill time: estimate=-1.0 s, 95% CI:-1.3 to -0.7, P < 0.0001).

CLINICAL SIGNIFICANCE

In this population of dogs with circulatory shock, the caudal vena cava to aorta ratio significantly increased after a fluid bolus. Future studies that implement blinding of the outcome assessors are warranted to confirm these findings.

Novel Approaches to the Establishment of Local Microenvironment from Resorbable Biomaterials in the Brain In Vitro Models

The development of brain in vitro models requires the application of novel biocompatible materials and biopolymers as scaffolds for controllable and effective cell growth and functioning. The "ideal" brain in vitro model should demonstrate the principal features of brain plasticity like synaptic transmission and remodeling, neurogenesis and angiogenesis, and changes in the metabolism associated with the establishment of new intercellular connections. Therefore, the extracellular scaffolds that are helpful in the establishment and maintenance of local microenvironments supporting brain plasticity mechanisms are of critical importance. In this review, we will focus on some carbohydrate metabolites-lactate, pyruvate, oxaloacetate, malate-that greatly contribute to the regulation of cell-to-cell communications and metabolic plasticity of brain cells and on some resorbable biopolymers that may reproduce the local microenvironment enriched in particular cell metabolites.

Rest reduces venous lactate levels significantly in patients in outpatient clinic

Lactate is produced in the human body during physical activity and elimination takes time with a half-life of approximately 18 min. We, therefore, investigated the potential impact of resting time (RT) duration on lactate concentration in our outpatient venipuncture clinic for all lactate requests during a 4½-year period. All samples drawn for venous lactate analysis during a 4½-year period in our hospital outpatient venipuncture clinics were included in this study. RT was reported electronically at each visit. Results from a total of 831 samples were obtained for further analysis. We found varying lactate concentrations across resting time <15min (median 1.6 mmol/L, IQR[1.2-2.1] mmol/L), between <15 min and >30 min (median 1.4 mmol/L, IQR[1.0-1.9] mmol/L) and for >30 min (median 1.3 mmol/L, IQR[1.0-1.7] mmol/L). There was a significant difference between <15 min versus 15-30 min (p = 0.015), which gives a 17.7% higher lactate from 15-30 min to <15 min. There was a significant 28.3% increase in mean lactate concentration from >30min to <15min (p < 0.0001) when corrected for age. We found that lactate concentration was dependent on RT in the outpatient clinic. The difference was clinically significant. Based on the results of this study, we, therefore, conclude that a 15 min waiting time before venipuncture for lactate sampling in an outpatient clinic is of clinical importance.

A comparison of the Sepsis-2 and Sepsis-3 definitions for assessment of mortality risk in dogs with parvovirus

OBJECTIVE

To evaluate the use of a modified Sepsis-3 (mSepsis-3) definition compared to the currently used modified Sepsis-2 (mSepsis-2) definition to determine whether the mSepsis-2 or mSepsis-3 stratifications were able to identify populations of dogs ultimately more likely to die from canine parvovirus (CPV) infection.

DESIGN

Retrospective, January 2009 to March 2020.

SETTING

A private, small animal, urban, referral emergency and specialty hospital.

ANIMALS

Fifty-nine client-owned dogs hospitalized for treatment of CPV.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Dogs were divided into mSepsis-2 and mSepsis-3 categories based on the highest level of illness severity reached during hospitalization. Greater illness severity based on mSepsis-2 criteria (ie, sepsis, severe sepsis, septic shock) was associated with an increase in average length of stay (P < 0.001), increase in average cost of stay (P < 0.01), and presence of leukopenia (P < 0.05). An increase in illness severity within the mSepsis-2 criteria was not associated with hyperlactatemia (P = 0.29), presence of neutropenia (P = 0.12), or mortality (P = 0.35). Greater illness severity based on mSepsis-3 criteria (ie, infection only, sepsis, septic shock) was associated with an increase in mortality (P < 0.05), increase in average length of stay (P < 0.001), increase in average cost of stay (P < 0.01), presence of leukopenia (P < 0.01), and presence of neutropenia (P < 0.05). The mSepsis-3 criteria were not associated with the presence of hyperlactatemia (P = 0.68). There was no significant difference between survivors and nonsurvivors in the presence of leukopenia (P = 0.19), neutropenia (P = 0.67), or hyperlactatemia (P = 0.58).

CONCLUSIONS

The mSepsis-3 diagnostic criteria appear to better identify dogs with CPV at higher risk for mortality compared to the mSepsis-2 criteria.

INVESTIGATING BLOOD LACTATE CONCENTRATION AS A PROGNOSTIC INDICATOR FOR BIRDS PRESENTING WITH BREVETOXICOSIS: 2020-2021

Large blooms of the dinoflagellate Karenia brevis cause annual harmful algal bloom events, or "red tides" on Florida's Gulf Coast. Each year, the Clinic for the Rehabilitation of Wildlife (CROW) is presented with hundreds of cases of aquatic birds that exhibit neurologic clinical signs due to brevetoxicosis. Double-crested cormorants (Phalacrocorax auratus) are the most common species seen, and typically present with a combination of ataxia, head tremors, knuckling, and/or lagophthalmos. Blood lactate levels are known to increase in mammals for a variety of reasons, including stress, hypoxia, sepsis, and trauma, but there is limited literature on blood lactate values in avian species. The objective of this study was to determine the prognostic value of blood lactate concentration on successful rehabilitation and release of birds presenting with clinical signs consistent with brevetoxicosis. Blood lactate levels were collected on intake, the morning after presentation and initial therapy, and prior to disposition (release or euthanasia) from 194 birds (including 98 cormorants) representing 17 species during the 2020-2021 red tide season. Overall, mean blood lactate at intake, the morning after intake, and predisposition was 2.9, 2.8, and 3.2 mmol/L, respectively, for released birds across all species (2.9, 2.9, and 3.2 mmol/L for released cormorants); 3.4, 3.4, and 6.5 mmol/L for birds that died (4.0, 3.5, and 7.9 mmol/L for cormorants that died); and 3.1, 3.5, and 4.7 mmol/L for birds that were euthanized (3.5, 4.7, and 4.9 mmol/L for cormorants that were euthanized). On average, birds that died or were euthanized had an elevated lactate at all time points as compared to those that were released, but these results were not statistically significant (P = 0.13). These results indicate that blood lactate levels do not appear to be useful as a prognostic indicator for successful release of birds, including double-crested cormorants, affected by brevetoxicosis.

Case report: Severe, refractory hypoglycemia in a 9-year-old Brittany Spaniel with renal nephroblastoma

A 9-year-old female spayed Brittany Spaniel presented for weakness and stumbling, and was diagnosed with severe hypoglycemia. An insulin to glucose ratio was not consistent with insulinoma as a cause for hypoglycemia. Diagnostic imaging (abdominal ultrasound and computed tomography) revealed a large left renal mass and a possible metastatic lesion in the right kidney. Glucagon therapy was initiated, but hypoglycemia was refractory to therapy. A left nephrectomy was performed and hypoglycemia subsequently resolved. Histopathology of the mass was consistent with nephroblastoma and immunohistochemistry for anti-insulin-like Growth Factor-2 (IGF-2) antibody revealed immunoreactivity in over 50% of the neoplastic cells. Chemotherapeutic treatment was initiated with a combined protocol of vincristine and doxorubicin. To the authors' knowledge, this is the first case report documenting the treatment of severe, refractory non-islet cell tumor-induced hypoglycemia in a dog, suspected to be secondary to an IGF-2 secreting nephroblastoma.

Lactic Acidosis in Patients with Solid Cancer

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

Prognostic value of lactate in cats presented in respiratory distress to the emergency room

Studies demonstrating the prognostic utility of plasma lactate concentration and lactate clearance in cats are limited. The objective of this study was to determine the prognostic utility of plasma lactate concentration upon admission and plasma lactate clearance in cats presented to the emergency room with respiratory distress attributed to underlying cardiac or respiratory disease. Additionally, we sought to determine if plasma lactate concentration on admission was significantly associated with the underlying cause of respiratory distress (cardiac vs. respiratory), type of respiratory disease, and vital parameters. Seventy-one cats presented in respiratory distress to the ER at a university teaching hospital were enrolled in this retrospective study. Admission lactate concentration was not associated with survival, duration of hospitalization, vital parameters, or underlying etiology for respiratory distress. In contrast, lactate clearance was significantly associated with survival and length of hospitalization. While a statistically significant association between lactate clearance and length of hospitalization was identified, this finding lacked clinical significance where an increase in lactate concentration by 1% was associated with an increased length of hospitalization by 11.4 min (p = 0.035). Results of this study suggest that lactate clearance may have prognostic utility in this population of cats. Further studies including the larger population of cats with underlying cardiac or respiratory disease are warranted.

Effect of washing units of canine red blood cells on storage lesions

Background

In humans, washing stored blood products before transfusion reduces storage lesions and incidence of transfusion reactions, but the effectiveness of washing canine blood is unknown.

Objectives

The objective was to determine if manually washing units of stored blood would reduce storage lesions without adversely affecting erythrocytes. We hypothesized that washing stored units would reduce concentrations of storage lesions and cause minimal erythrocyte damage.

Animals

Eight healthy research dogs.

Methods

Repeated measure cohort study. Units of whole blood were stored for 28 days and washed 3 times with 0.9% NaCl. Blood samples were collected before and after storage, after each wash, and after being held at a simulated transfusion temperature. Variables measured included CBC variables, blood gas analysis, erythrocyte morphology, mean corpuscular fragility (MCF), and eicosanoid concentrations. A Friedman's test was used to evaluate changes in variables (P < .05 was considered significant).

Results

After the first wash, compared to values after storage, there was a significant decrease in potassium (4.3 mmol/L [4.0‐4.7] to 1.2 mmol/L [1‐1.6]; P < .0001, median [range]), lactate (1.45 mmol/L [1.07‐1.79] to 0.69 mmol/L [0.39‐0.93]; P = .002), and partial pressure carbon dioxide (102 mm Hg [80.2‐119.2] to 33.7 mm Hg [24.5‐44.5]; P < .0001), and increase in MCV (69.3 fL [65.7‐72.3] to 74 fL [69.6‐79.5]; P = .0003), and MCF (0.444 fL [0.279‐0.527] to 0.491 fL [0.43‐0.616]; P = .0006).

Conclusions and Clinical Importance

A single wash of stored whole blood significantly reduces most extracellular storage lesions, and additional washing might cause hemolysis.

Effects of time on differential leucocyte counts and biochemical parameters of ovariohysterectomy, gastrotomy and intestinal resection and anastomosis in Nigerian indigenous dogs

Differential leucocytes counts and some biochemical parameters could be affected over time by surgical procedures leading to kidney failure. Hence this study evaluates the effects of ovariohysterectomy (OVH), gastrotomy (GAT) and intestinal resection and anastomosis (ITR) on differential leucocyte counts and some biochemical parameters in Nigerian dogs. Twelve dogs of both sexes weighing 10.8±0.7 kg were randomly divided into three experimental groups of four each. The dogs were pre-treated with atropine sulphate (0.04 mg/kg), Xylazine (2 mg/kg) and propofol (6 mg/kg) parenterally, for induction and maintenance of anaesthesia. Pentazocine (3 mg/kg) was injected after surgery. Pre and post-surgery blood samples were obtained at 0, 2, 24, 48, 72, 96, 120 and 144 h respectively to determine differentials in leucocyte counts, electrolytes, lactate, blood urea nitrogen (BUN) and serum creatinine. Mathematical formulas were used to calculate plasma creatinine, creatinine clearance, plasma creatinine clearance, creatinine half- life, urine creatinine and urine volume. There were significant increases (p ≤ 0.05) in mean sodium, chloride and bicarbonate concentrations at 2, 24, 48, 72, 96 and 120 h post-surgery in group 1 and 2, while group 3 had significant decreases (p ≤ 0.05) in sodium, chloride and bicarbonate ions. Lactate value decreased significantly (p<0.05) in group 1, and increased in group 2 and 3 respectively.BUN increased significantly (p<0.05) in group 1,2 and 3.However, there were significant increases (p<0.05) in lymphocyte concentrations in group 1 and 3, respectively. Monocytes decreased significantly (p<0.05) after surgery. Conclusion: Xylazine and propofol anaesthetics cause hyperlactatemia which can be detrimental in surgical patients with co-morbidities.

Outcomes and Blood Product Use in 89 Surgically Managed and 79 Medically Managed Cases of Acute Spontaneous Hemoperitoneum in the Dog

Objective: To describe a population of dogs with acute spontaneous hemoperitoneum (ASH) that were treated with either surgical or medical management in the first 12 h after presentation, and to perform a preliminary investigation into whether there were differences in achieving cardiovascular stabilization or patterns of red blood cell (RBC) transfusion between patients treated with early (<12 h) surgery vs.medical management. Design: A retrospective multicenter preliminary study performed on 168 dogs presenting with ASH between January 2015 and May 2019. Patients were excluded if they were euthanized or discharged from hospital within the first 12 h, or if clinical records were incomplete. All patients received appropriate medical stabilization efforts. Statistical analysis was performed comparing patients that underwent early (<12 h) surgery and those that did not. Results: Eighty-nine patients were in the early surgical group and 79 patients in the medical group. A significantly higher proportion of medical cases were euthanized (p < 0.001). A significantly higher proportion of early surgical cases were discharged from hospital (p = 0.005). There was no statistically significant difference between groups in achieving cardiovascular stabilization (OR 1.07 p = 0.82). A higher proportion of patients with body-weight over 20 kg achieved stabilization within 12 h than those with body-weight of 20 kg or less (62.7 vs. 41.4%, p < 0.01). A higher proportion of patients with splenic conditions achieved stabilization than patients with non-splenic conditions (56.5 vs. 28.6%, p = 0.05). The odds of receiving an RBC transfusion were higher in the early surgical group than the medical group [OR 3.81 (p < 0.001)]. Conclusions: This preliminary study did not identify a significant difference in the ability to achieve cardiovascular stabilization in the first 12 h in dogs with ASH that underwent early surgical intervention vs. those managed medically. Patients in the early surgical group were more likely to receive a RBC transfusion than those in the medical group. At this time the decision on whether to pursue medical or early surgical management should be made on a case by case basis.

BLOOD LACTATE CONCENTRATIONS IN EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) FOLLOWING CAPTURE BY A CANINE SEARCH TEAM

Studies to assess wildlife health commonly evaluate clinical pathology changes, immune responses, pathogen presence, and contaminant exposure, but novel modalities are needed to characterize the unique physiologic responses of reptiles. Lactate is an indicator of hypoperfusion and/or anaerobic respiration and can be quickly and easily measured using a point-of-care analyzer. This study evaluated baseline blood lactate concentrations in free-living eastern box turtles (Terrapene carolina carolina, n = 116) using a point of care analyzer and then determined the effect of handling time, physical examination (PE) abnormalities, and quantitative polymerase chain reaction pathogen detection (Terrapene herpesvirus 1, Mycoplasma sp., Terrapene adenovirus) on lactate concentrations. Blood lactate concentrations were higher in turtles with Terrapene herpesvirus 1 (n = 11), quiet mentation, and increased packed cell volume (P < 0.05). Lactate concentrations increased between initial capture and PE, with peak values reaching 129 min after capture. Lactate at PE was positively associated with baseline lactate concentrations. Turtles with Terrapene herpesvirus 1 may have alterations in blood flow, oxygen delivery, or activity patterns, driving increases in baseline lactate. Increased handling time likely leads to more escape behaviors and/or breath holding, causing turtles to undergo anaerobic metabolism and raising lactate concentrations. Overall, lactate measured by a point of care analyzer shows variability caused by capture and health factors in eastern box turtles and may be a useful adjunctive diagnostic test in this species after full methodologic validation.

Physiologic and blood gas effects of xylazine-ketamine versus xylazine-tiletamine-zolazepam immobilization of white-tailed deer before and after oxygen supplementation: a preliminary study

OBJECTIVE

To compare oxygenation and ventilation in white-tailed deer (Odocoileus virginianus) anesthetized with two treatments with and without oxygen supplementation.

STUDY DESIGN

Randomized, blinded, crossover study.

ANIMALS

A total of eight healthy adult white-tailed deer weighing 49-62 kg.

METHODS

Each deer was anesthetized twice intramuscularly: 1) treatment XK, xylazine (2 mg kg^-1) and ketamine (6 mg kg^-1) and 2) treatment XTZ, xylazine (2 mg kg^-1) and tiletamine-zolazepam (4 mg kg^-1). With the deer in sternal position, arterial and venous blood was collected before and at 30 minutes during administration of oxygen at 1 L minute^-1 through a face mask. PaO₂ and heart rate (HR) were compared using two-way repeated measures anova. pH, PaCO₂ and lactate concentration were analyzed using mixed-effects linear models, p < 0.05.

RESULTS

When breathing air, PaO₂ was < 80 mmHg (10.7 kPa) in six and seven deer with XK and XTZ, respectively, and of these, PaO₂ was < 60 mmHg (8.0 kPa) in three and five deer, respectively. With oxygen supplementation, PaO₂ increased to 128 ± 4 and 140 ± 5 mmHg (17.1 ± 0.5 and 18.7 ± 0.7 kPa), mean ± standard error, with XK and XTZ, respectively (p < 0.001). PaO₂ was not significantly different between treatments at either time point. HR decreased during oxygen supplementation in both treatments (p < 0.001). Lactate was significantly lower (p = 0.047) with XTZ than with XK (2.2 ± 0.6 versus 3.5 ± 0.6 mmol L^-1) and decreased (p < 0.001) with oxygen supplementation (4.1 ± 0.6 versus 1.6 ± 0.6 mmol L^-1). PaCO₂ increased in XTZ during oxygen breathing.

CONCLUSIONS AND CLINICAL RELEVANCE

Treatments XK and XTZ resulted in hypoxemia, which responded to oxygen supplementation. Both treatments are suitable for immobilization of white-tailed deer under the study circumstances.

Terms, Definitions, Nomenclature, and Routes of Fluid Administration

Fluid therapy is administered to veterinary patients in order to improve hemodynamics, replace deficits, and maintain hydration. The gradual expansion of medical knowledge and research in this field has led to a proliferation of terms related to fluid products, fluid delivery and body fluid distribution. Consistency in the use of terminology enables precise and effective communication in clinical and research settings. This article provides an alphabetical glossary of important terms and common definitions in the human and veterinary literature. It also summarizes the common routes of fluid administration in small and large animal species.

Clinical and biochemical factors associated with survival in equids attacked by dogs: 28 cases (2008-2016)

Background

Trauma from dog attacks has been associated with mortality rates as high as 23% in some species. However, the prognosis and clinical features of this type of injury have not been described in equids.

Hypotheses/Objectives

To describe survival rate, signalment, clinical features, and biochemical results in equids presented for emergency care after presumed dog attacks. We hypothesized there would be differences between survivors and nonsurvivors.

Animals

A total of 28 equids presented for presumed dog attacks from 3 referral centers.

Methods

A retrospective study was performed using data from 3 hospitals between 2008 and 2016. Survival was defined as survival at 14 days postdischarge. Variables were compared between survivors and nonsurvivors using a t test, Mann‐Whitney U test, or Fisher's exact test as appropriate.

Results

Overall mortality rate was 21%. Ponies and miniature horses represented 16/28 (57%) of the animals in the study. Full‐sized equids had a lower risk of nonsurvival as compared to smaller patients (odds ratio = 0.02; 95% confidence intervals = 0.00‐0.27; P < .005). Animals with lower body temperatures had increased risk for nonsurvival (P = .0004). Increased admission blood lactate concentrations (P = .003) and decreased serum total protein concentrations (P = .006) were associated with nonsurvival.

Conclusions

The mortality rate in equids attacked by dogs was similar to what is reported for other veterinary species. Smaller equids and those with increased admission blood lactate concentration, lower body temperature, and lower total serum protein concentrations were less likely to survive.

Comparison of wavelength selection methods for in-vitro estimation of lactate: a new unconstrained, genetic algorithm-based wavelength selection

Biochemical and medical literature establish lactate as a fundamental biomarker that can shed light on the energy consumption dynamics of the body at cellular and physiological levels. It is therefore, not surprising that it has been linked to many critical conditions ranging from the morbidity and mortality of critically ill patients to the diagnosis and prognosis of acute ischemic stroke, septic shock, lung injuries, insulin resistance in diabetic patients, and cancer. Currently, the gold standard for the measurement of lactate requires blood sampling. The invasive and costly nature of this procedure severely limits its application outside intensive care units. Optical sensors can provide a non-invasive, inexpensive, easy-to-use, continuous alternative to blood sampling. Previous efforts to achieve this have shown significant potential, but have been inconclusive. A measure that has been previously overlooked in this context, is the use of variable selection methods to identify regions of the optical spectrum that are most sensitive to and representative of the concentration of lactate. In this study, several wavelength selection methods are investigated and a new genetic algorithm-based wavelength selection method is proposed. This study shows that the development of more accurate and parsimonious models for optical estimation of lactate is possible. Unlike many existing methods, the proposed method does not impose additional locality constraints on the spectral features and therefore helps provide a much more granular interpretation of wavelength importance.

Prognostic utility of pre- and postoperative plasma l-lactate measurements in hospitalized cows with acute abdominal emergencies

The aim of the present analyses was to compare the prognostic value of pre- and postoperative l-lactate measurements in hospitalized cows requiring surgical intervention for an acute abdominal emergency, such as gastrointestinal ileus or peritonitis. For this purpose, we analyzed data from retro- and prospective case series, consisting of 754 and 98 cows, respectively. Plasma l-lactate concentrations (L-LAC) were determined upon admission to the hospital (both study populations), immediately before initiation of surgical intervention (prospective study population), and 6, 12, 24, 48, and 72 h later (prospective study population). The outcome of cows was evaluated until hospital discharge (both study populations) and 3 mo after discharge by a phone call to the farmer (prospective study population). A negative outcome was defined as death or euthanasia during hospitalization, or if discharged animals had an unsatisfied owner or were culled for medical reasons that were directly related to the initial abdominal emergency. For the retrospective study population, the overall survival rate until hospital discharge was 66%. Cows with a negative outcome (median: 6.81 mmol/L) had significantly higher L-LAC than cows with a positive outcome (3.66 mmol/L) of therapy. At the individual diagnosis level, L-LAC was associated with mortality in cows with a diagnosis of abomasal volvulus, local peritonitis, hemorrhagic bowel syndrome, and jejunal volvulus. Considering the whole study population, the area under the receiver operating characteristic curve was 0.66. For the prospective study population, the proportion of cows with a positive outcome was 65% until hospital discharge and 61% after the 3-mo observation period. At all sampling times, before and during the first 12 h after surgical intervention, cows with a negative outcome had significantly higher L-LAC than cows with a positive outcome. The largest area under the receiver operating characteristic curve for L-LAC was observed at 6 h (0.89). A cut-point of 1.77 mmol/L was identified, which had a sensitivity and specificity for predicting a negative outcome until hospital discharge of 88.9 and 73.4%, respectively. The present analyses confirmed previous findings in calves and show that persistent hyper-l-lactatemia during the early postoperative period is a more reliable indicator for a negative outcome than hyper-l-lactatemia before initiation of surgical intervention.

Clinicopathological abnormalities associated with increased animal triage trauma score in cats presenting for vehicular trauma: 75 cases (1998-2009)

OBJECTIVE

To document the clinical and clinicopathological changes in cats presenting with vehicular trauma (VT) and to determine whether the calculated animal trauma triage (ATT) score was associated with any clinicopathological abnormalities.

DESIGN

Retrospective descriptive study conducted between 1998 and 2009.

SETTING

University veterinary teaching hospital.

ANIMALS

Seventy-five client-owned cats that presented for VT to an urban veterinary hospital.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Pertinent history, physical examination findings, results of biochemical testing, and outcome were extracted from medical records. ATT score was calculated based on physical examination. Patients were classified as having either a low (<5) ATT (n = 30) or a high (≥5) ATT (n = 45) score. Male cats were overrepresented (60.0%), and a majority of cats had outdoor access (65.3%). Low PCV (P = 0.024), low total plasma protein concentration (P = 0.032), low venous blood pH (P = 0.047), high plasma lactate concentration (P = 0.047), low plasma bicarbonate concentration (P = 0.047), low base excess (P = 0.047), and high plasma glucose concentration (P = 0.047) were associated with higher ATT scores. In addition, low noninvasive blood pressure measurements (P = 0.008) were associated with higher ATT scores.

CONCLUSIONS

There was a significant association between lower PCV, lower total plasma protein concentration, lower venous blood pH, higher plasma lactate concentration, lower plasma bicarbonate concentration, lower base excess, higher whole blood glucose concentration, and lower noninvasive blood pressure and higher ATT scores at presentation in feline patients suffering from VT. Prospective evaluation of these values may prove useful in furthering understanding of the pathophysiology of trauma in cats.

Retrospective evaluation of the influence of azotemia on plasma lactate concentrations in hypotensive dogs and cats (2008-2018): 337 cases

OBJECTIVE

To evaluate the relationship between azotemia and plasma lactate concentration in hypotensive dogs and cats presented to an emergency department.

DESIGN

Retrospective case-control study.

SETTING

University veterinary teaching hospital.

ANIMALS

The electronic medical record database was searched for dogs and cats presented to the emergency department that had severe azotemia (creatinine ≥ 443.1 μmol/L [5 mg/dL]), hypotension (systolic blood pressure ≤ 90 mm Hg), and a plasma lactate measurement within 2 h of each another. Non-azotemic, normotensive dogs and cats; non-azotemic, hypotensive dogs and cats; and azotemic, normotensive dogs and cats that presented to the emergency department were used as control populations.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Severely azotemic, hypotensive dogs (n = 10) and cats (n = 63) had a lower plasma lactate than non-azotemic, hypotensive dogs and cats (P = 0.031 and P < 0.001, respectively). Median plasma lactate concentrations in hypotensive dogs (1.75 mmol/L) and cats (1.90 mmol/L) with severe azotemia were within reference intervals.

CONCLUSIONS

Hypotensive dogs and cats with severe azotemia have decreased plasma lactate concentrations as compared to hypotensive, non-azotemic dogs and cats. The median plasma lactate in azotemic, hypotensive dogs and cats was within reference intervals. This may be due to either decreased cellular production of lactate or increased excretion of lactate. Further research is needed to determine which of these mechanisms is responsible and the clinical significance of plasma lactate concentrations in azotemic, hypotensive dogs and cats.

Near Infrared Spectrometric Investigations on the behaviour of Lactate

In patients with life-threatening illnesses, the metabolic production and disposal of lactate are impaired, which leads to a build-up of blood lactate. In critical care units, the changes in lactate levels are measured through intermittent, invasive, blood sampling and in vitro assay. Continuous monitoring is lacking, yet such monitoring could allow early assessment of severity and prognosis to guide therapy. Currently, there is no routine means to measure lactate levels continuously, particularly non-invasively. The motivation of this study was to understand the interaction of lactate with light in the Near Infra Red (NIR) region of the electromagnetic spectrum. This was to create an opportunity to explore the possibility of a non-invasive sensing technology to monitor lactate continuously.In vitro studies were performed using solution samples with varying concentration levels of sodium lactate in isotonic Phosphate Buffer Solution (PBS) at constant pH (7.4). These samples were prepared using stoichiometric solution compositions and spectra for each sample were taken using a state-of-the-art spectrometer in the NIR region. The spectra were then analysed qualitatively by 2D correlation analysis, which identified the regions of interest. Further analysis of these regions using linear regression at four randomly selected wavelengths showed bathochromic shifts, which, moreover, showed systematic variation correlating with lactate concentration.

Cytokine and Chemokine Profiling in Cats With Sepsis and Septic Shock

Background: Sepsis is a life-threatening condition associated with an exacerbated production of both pro- and anti-inflammatory cytokines that can promote a hyperactive response to infection or induce immunoparalysis. Data regarding the immune response to sepsis in cats are scarce. Establishing the profiles of cytokines and chemokines in feline sepsis to characterize the nature of the immune responses to sepsis might enable individualized treatments to be developed and targeted.

Objective: To evaluate the cytokine and chemokine network in cats with sepsis and septic shock, and to investigate the associations of these analytes with disease severity and outcome.

Methods: Blood samples prospectively collected at presentation of cats with sepsis and septic shock to two veterinary teaching hospitals were analyzed. Forty healthy cats were included as controls. A 19-plex feline cytokine/chemokine magnetic bead assay system was used to measure analytes in citrated plasma samples. Cytokine concentrations were compared between groups using the Kruskal-Wallis test with Dunn's post-hoc correction for multiple comparisons. Cytokine concentrations were compared between survivors and non-survivors with the Mann-Whitney U test. Odds ratios were calculated using logistic regression. A multivariable logistic regression model for prediction of septic shock was constructed.

Results: The study enrolled 35 septic cats. Many cytokines were undetectable in both sick and healthy control cats and were excluded from subsequent analyses. Comparisons of cytokine concentrations among healthy controls, cats with sepsis (n = 12) and cats with septic shock (n = 23) revealed that sick cats (sepsis or septic shock) had significantly higher plasma concentrations of IL-6, IL-8, KC-like, and RANTES compared to healthy controls. The combination of MCP-1, Flt-3L, and IL-12 was predictive of septic shock. None of the cytokines analyzed was predictive of outcome in this study population.

Conclusion: Plasma concentrations of IL-6, IL-8, KC-like, and RANTES are increased in cats with sepsis and may play important roles in pathogenesis. Multivariable modeling suggested that analysis of cytokines might aid differentiation of septic shock from sepsis. None of the cytokines analyzed was predictive of outcome. Measurement of these cytokines might enable future studies to better diagnose and characterize feline sepsis and septic shock.

Evaluation of the relationship between lactacidemia and postoperative complications after surgery for peritoneal carcinomatosis

Background

Cytoreductive surgery was developed as a treatment for peritoneal carcinomatosis. However, this surgery is associated with important complications. The present study aimed to assess the relationship between lactacidemia and the rate of associated complications during the immediate postoperative period in the intensive care unit (ICU) in patients undergoing cytoreductive surgery.

Methods

This was a retrospective observational study. A total of 57 patients underwent cytoreductive surgery. All patients were admitted to the ICU immediately after the surgery. Data on lactic acid levels at the time of admission and discharge from the ICU were collected. Postsurgical complications that occurred during the ICU stay were recorded according to failure-to-rescue analysis and their severity stratified according to the Clavien-Dindo classification.

Results

The lactic acid levels at admission to the ICU were significantly higher in patients who developed complications, with an almost tripled unadjusted relative risk (2.9, 95% CI: 1.6, 5.3), than in those who did not develop complications for the lactacidemia threshold established in the cumulative sum curve graphs. After adjustment for confounding effects, the relative risk became even higher (3.1, 95% CI: 1.8, 3.6). Lactic acid levels were still significantly higher in this group at the time of discharge from the ICU.

Conclusions

Serum lactate level is a risk factor for postoperative complications in patients undergoing cytoreductive surgery for peritoneal carcinomatosis. This study suggests that the risk of developing severe complications almost triples with a lactic acid level of 2.5 mmol/L or higher at the time of admission in the ICU.

Recognition, Treatment, and Monitoring of Canine Hypovolemic Shock in First Opinion Practice in the United Kingdom

The aim of this study was to gain a greater understanding of the detection, treatment, and monitoring of hypovolemic shock (HVS) in dogs by general practitioners in the United Kingdom (UK). An online survey was devised and distributed by email to first opinion practices in the UK. All veterinarians working in first opinion practice treating small animals were eligible to complete the survey. Most respondents (n = 164, 93%) were confident with HVS diagnosis. Isotonic crystalloid fluids were the most common fluid type for first-line treatment and administered as a 10-30 mL/kg bolus over 10-30 minutes by 57% respondents. Initial intravenous isotonic crystalloid fluid rates for HVS management ranged from maintenance fluid requirements to 90 mL/kg/hr for an undefined time period. A synthetic colloid was the most popular second-line fluid choice, typically considered after a total administered volume of 60-90 mL/kg of isotonic crystalloid fluids. Only 72 respondents (40.7%) were able to measure blood lactate in-house, which was used routinely by 36 respondents (20.3%) for initial treatment decision making. Respondents treating HVS most frequently were more likely to use lactate for initial decision making (P = .008). This study highlighted variabilities in the initial approach, fluid management strategies and monitoring instituted by UK general practitioners when faced with canine patients in HVS. This suggests that there is a discrepancy in what is determined to be the most optimal diagnostic and treatment plan for canine HVS patients.

Acid-Base, Electrolyte and Lactate Abnormalities as Well as Gastric Necrosis and Survival in Dogs With Gastric Dilation-Volvulus Syndrome. A Retrospective Study in 75 Dogs

Gastric dilation-volvulus (GDV) syndrome in dogs is associated with complex metabolic, acid-base, and electrolyte abnormalities. The aim of this study was to evaluate previously analyzed factors (lactate and BE) in combination with other acid-base parameters (pH, pCO₂, bicarbonate, base excess [BE], anion gap [AG], and strong ion difference) and electrolyte concentrations and to evaluate their association with the incidence of gastric necrosis and outcome in dogs with GDV. A retrospective study in 75 dogs with gastric dilation-volvulus syndrome, University veterinary teaching hospital. Medical records were reviewed including signalment, history, initial plasma lactate, acid-base parameters, and electrolyte concentrations, surgical findings and outcome. The overall mortality was 18.7%. In dogs with gastric necrosis, higher initial plasma lactate (median 5.84 vs. 3.36 mmol/L) and AG (20.7 vs. 16.55 mmol/L) and lower pH (7.29 vs. 7.36), bicarbonate (18.7 vs. 22.9 mmol/L), and BE concentration (-8.1 vs. -1.85 mmol/L) were found compared to dogs without gastric necrosis. Anorganic phosphorus was the only electrolyte investigated for which a significant difference was noted between dogs with and without gastric necrosis (1.93 vs. 1.39 mmol/L). The initial plasma lactate concentration (3.36 mmol/L vs. 9.68 mmol/L) and AG (16.8 vs. 20.95 mmol/L) were lower in survivors than nonsurvivors. Survivors had higher pH (7.35 vs. 7.27), bicarbonate concentrations (22.9 vs. 17.35 mmol/L), and BE (-1.9 vs. -9.55 mmol/L) compared to nonsurvivors. Anorganic phosphorus was ultimately the only electrolyte with a significant difference between survivors and nonsurvivors (1.4 vs. 1.84 mmol/L). A multivariate logistic regression model of combination lactate, pH, bicarbonate, BE, AG, and anorganic phosphorus identified pH ≤7.331 and bicarbonate as factors independently associated with gastric necrosis. Similarly, pH ˃7.331, bicarbonate and anorganic phosphorus were independently associated with outcome. Higher initial plasma lactate, AG and anorganic phosphorus levels, and lower pH, BE and bicarbonate concentrations were found in GDV dogs with gastric necrosis. Similarly, initially higher plasma lactate, AG and anorganic phosphorus concentrations, and lower pH, BE and bicarbonate were found in GDV dogs who required euthanasia or who died after surgery. Of these parameters, pH and bicarbonate were strongly and independently associated with gastric necrosis, and pH, bicarbonate and phosphorus were independently associated with outcome.

Prognostic relevance of pre- and postoperative plasma l-lactate measurements in calves with acute abdominal emergencies

In both human and veterinary medicine, l-lactate is a well-established prognostic biomarker of disease severity and mortality and has also attracted increasing attention in bovine medicine due to the availability and validation of cheap and portable l-lactate analyzers. The aim of the present study was to evaluate the prognostic accuracy of plasma L-lactate measurements in calves with acute abdominal emergencies before and during the initial therapeutic period after surgical intervention. A prospective observational study was carried out involving 83 hospitalized calves up to an age of 7 mo, which required surgical intervention for reasons of an acute abdominal emergency such as gastrointestinal ileus or peritonitis. Plasma l-lactate (L-LAC) concentrations were determined immediately before initiation of surgery and 6, 12, 24, 48, and 72 h later. The outcome of calves was evaluated 3 mo after discharge by a phone call to the farmer, and a positive outcome was defined if the calf was still alive and the owner was satisfied with the animal's postsurgical progress. A total of 29% of calves were discharged from the hospital and the proportion of calves with a positive outcome after the 3-mo period was 24%. At all sampling times during the first 48 h after initiation of surgical intervention, calves with a negative outcome had significantly higher L-LAC than calves with a positive outcome. A binary logistic regression analysis indicated that the odds for a negative outcome during the 3-mo observation period increased by a factor of 1.23 [95% confidence interval (CI): 1.04-1.44] for every mmol/L increase of L-LAC before initiation of surgical intervention, but by a factor of 5.29 (95% CI: 1.69-16.6) and 5.92 (95% CI: 1.29-27.3) at 12 and 24 h, respectively. The largest area under the receiver operating characteristic curve for L-LAC was observed at 12 h (0.91; 95% CI: 0.83-0.99), and a cut-point of 2.75 mmol/L was identified that had a sensitivity and specificity for predicting a negative outcome of 68 and 100%, respectively. In conclusion, persistent hyper-l-lactatemia during the early postoperative period is a more reliable indicator for a negative outcome in calves with acute surgical abdominal emergencies than hyper-l-lactatemia before initiation of surgical intervention. Postoperative measurements of L-LAC are therefore a clinically useful tool to identify patients with an increased risk for a negative outcome at an early stage after surgical intervention was carried out.

Prognostic value of preoperative plasma l-lactate concentrations in calves with acute abdominal emergencies

Acute abdominal emergencies in calves due to abomasal disorders, gastrointestinal ileus, or peritonitis are characterized by a rapid disease progression and usually require immediate surgical intervention. Those conditions are associated with a guarded prognosis, and the aim of the present study was to assess the prognostic relevance of preoperatively measured plasma l-lactate concentrations (l-LAC) in a large study population of calves with a broad spectrum of acute abdominal emergencies. For the purpose of this study, the medical records of 587 calves admitted to a veterinary teaching hospital over a 10-yr period were analyzed retrospectively. Plasma l-LAC was measured as part of a routinely performed biochemistry panel before initiation of surgical intervention. Hyper-l-lactatemia (plasma l-LAC >2.2 mmol/L) was evident in 75% of calves, and the overall survival rate until hospital discharge was 31%. Calves with a negative outcome were younger (median: 3.4 vs. 6 wk) and had higher plasma l-LAC (median: 4.96 vs. 3.09 mmol/L) than calves with a positive outcome. At the individual diagnosis level, l-LAC was associated with mortality in calves with a diagnosis of mesenteric torsion, right-sided dilated abomasum, small intestinal volvulus, or paralytic ileus, but not in calves suffering from peritonitis, malformations, abomasal volvulus, bloat, or small intestinal intussusceptions. Considering the whole study population, the area under the receiver operating characteristic (ROC) curve for plasma l-LAC was 0.66 [95% confidence interval (CI): 0.61-0.70]. A classification tree analysis indicated that l-LAC >8.84 mmol/L and age categories of <3 wk and <1 wk were independent predictors of mortality. The area under the ROC curve of this model was 0.75 (95% CI: 0.71-0.79) and the resulting sensitivity and specificity for the prediction of nonsurvival at the optimal probability cut-point of 0.62 were 67.7 and 76.6%, respectively. In conclusion, hyper-l-lactatemia is common in calves suffering from acute abdominal emergencies. Markedly increased plasma l-LAC is associated with an increased mortality risk, but it is not possible to reliably predict the outcome of affected calves based on a single, preoperative measurement. However, a clinically important finding of this study was that the ability to predict a negative outcome is improved when the age of the calf is considered in addition to plasma l-LAC.

Clinical use of plasma lactate concentration. Part 2: Prognostic and diagnostic utility and the clinical management of hyperlactatemia

OBJECTIVE

To review the current literature pertaining to the use of lactate as a prognostic indicator and therapeutic guide, the utility of measuring lactate concentrations in body fluids other than blood or plasma, and the clinical management of hyperlactatemia in dogs, cats, and horses.

DATA SOURCES

Articles were retrieved without date restrictions primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection.

HUMAN AND VETERINARY DATA SYNTHESIS

Increased plasma lactate concentrations are associated with increased morbidity and mortality. In populations with high mortality, hyperlactatemia is moderately predictive in identifying nonsurvivors. Importantly, eulactatemia predicts survival better than hyperlactatemia predicts death. Consecutive lactate measurements and calculated relative measures appear to outperform single measurements. The use of lactate as a therapeutic guide has shown promising results in people but is relatively uninvestigated in veterinary species. Increased lactate concentrations in body fluids other than blood should raise the index of suspicion for septic or malignant processes. Management of hyperlactatemia should target the underlying cause.

CONCLUSION

Lactate is a valuable triage and risk stratification tool that can be used to separate patients into higher and lower risk categories. The utility of lactate concentration as a therapeutic target and the measurement of lactate in body fluids shows promise but requires further research.