Glucose, lactate, and pyruvate concentrations in dogs with babesiosis

Blood Parasites and Health Status of Hibernating and Non-Hibernating Noctule Bats (Nyctalus noctula)

Co-existence of bats with a wide range of infectious agents relates to their co-evolutionary history and specific physiology. Here, we examined blood samples collected during hibernation and the post-hibernation period to assess the influence of trypanosomes and babesias on the health status of 50 Noctule bats (Nyctalus noctula) using nested PCR. The impact of blood parasites on health was assessed by analysis of haematology and blood chemistry parameters in 21 bats. Prevalence of trypanosomes (Trypanosoma dionisii and T. vespertilionis) and babesia (Babesia vesperuginis) was 44% and 8%, respectively. Analysis of blood parameters indicated impact of babesia on acid–base balance. Blood chemistry parameters showed a significant decrease in total dissolved carbon dioxide and bicarbonate, increased anion gap, and no change in blood pH, suggesting compensated metabolic acidosis. Adverse effects of babesia were only apparent in hibernating bats. Our results suggest differences in the pathogenicity of trypanosomes and babesia in bats. While trypanosomes in general had no significant impact on the health status, we observed alterations in the blood acid–base balance in Babesia-infected bats during hibernation. Despite being infected, Babesia-positive bats survived hibernation without showing any clinical signs.

Multi Platforms Strategies and Metabolomics Approaches for the Investigation of Comprehensive Metabolite Profile in Dogs with Babesia canis Infection

Canine babesiosis is an important tick-borne disease worldwide, caused by parasites of the Babesia genus. Although the disease process primarily affects erythrocytes, it may also have multisystemic consequences. The goal of this study was to explore and characterize the serum metabolome, by identifying potential metabolites and metabolic pathways in dogs naturally infected with Babesia canis using liquid and gas chromatography coupled to mass spectrometry. The study included 12 dogs naturally infected with B. canis and 12 healthy dogs. By combining three different analytical platforms using untargeted and targeted approaches, 295 metabolites were detected. The untargeted ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) metabolomics approach identified 64 metabolites, the targeted UHPLC-MS/MS metabolomics approach identified 205 metabolites, and the GC-MS metabolomics approach identified 26 metabolites. Biological functions of differentially abundant metabolites indicate the involvement of various pathways in canine babesiosis including the following: glutathione metabolism; alanine, aspartate, and glutamate metabolism; glyoxylate and dicarboxylate metabolism; cysteine and methionine metabolism; and phenylalanine, tyrosine, and tryptophan biosynthesis. This study confirmed that host–pathogen interactions could be studied by metabolomics to assess chemical changes in the host, such that the differences in serum metabolome between dogs with B. canis infection and healthy dogs can be detected with liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) methods. Our study provides novel insight into pathophysiological mechanisms of B. canis infection.

Prospective evaluation of plasma lactate parameters for prognosticating dogs with shock

OBJECTIVE

To determine whether admission venous plasma lactate concentration, serially calculated lactate variables, or the Acute Patient Physiologic and Laboratory Evaluation (APPLE_fast ) score could discriminate hospital survivors from non-survivors in dogs presenting to the emergency department with clinical signs of shock.

DESIGN

Prospective case series performed over a 24-month period.

SETTING

Large urban private teaching hospital.

ANIMALS

Seventy-one dogs admitted to the ICU with initial peripheral venous plasma lactate concentration > 2.5 mmol/L and clinical and hemodynamic parameters consistent with shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Heart rate, systolic blood pressure, temperature, initial venous plasma lactate, and APPLE_fast score were recorded at admission. Lactate concentrations were serially recorded at predefined time points and used to calculate lactate variables, including lactime (time lactate > 2.5 mmol/L), lactate clearance ([lactate_initial - lactate_delayed ]/ lactate_initial × 100), and LAC_AREA (area under the lactate concentration versus time curve). Primary outcome was survival to discharge. Overall survival rate was 61%. Admission plasma lactate did not differ between groups (P = 0.28). Lactime was shorter in survivors vs non-survivors (P = 0.03). Lactate clearance at hours (h) 1, 4, 10, and 16 was greater in survivors vs non-survivors (P < 0.05). Final plasma lactate clearance differed between groups (P < 0.05). LAC_AREA at time intervals 1 to 4 hours, 4 to 10 hours, 10 to 16 hours, and 16 to 24 hours was larger in non-survivors vs survivors (P < 0.05). Total LAC_AREA did not differ between groups (P = 0.51). Admission APPLE_fast was not different between survivors and non-survivors (P = 0.16).

CONCLUSIONS

While neither single APPLE_fast nor admission plasma lactate concentration could discriminate between hospital survivors and non-survivors, measures of lactate clearance can prognosticate survival in dogs with shock.

Prognostic markers and their discriminant score in predicting the outcome of Babesia gibsoni infection

BACKGROUND

We aimed to identify prognostic markers and their discriminant score in predicting the lethal outcome of canine Babesia gibsoni.

METHODS

Blood samples were collected from 108 client-owned dogs with clinical signs commensurate with babesiosis to analyze haematological, biochemical, haemostatic, antioxidant profile and thiobarbituric acid reactive substance levels. Samples were screened for Babesia infection (microscopic and molecular techniques). Babesiosis-affected dogs were classified into survivors and non-survivors, and 30 healthy dogs were used in the control group.

RESULTS

Haemoglobin, thrombocytes, catalase, urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase, lactate and reticulocytes were highly correlated to survival. Receiver operating characteristics analysis revealed urea, ALT and lactate as specific prognostic markers for the disease. The formula for calculation of discriminant scores (Di) for lethal outcome of the disease was generated with cut-off score 0.141. The scoring system was 79% sensitive and 83% specific in predicting the lethal outcome of the disease.

CONCLUSIONS

A scoring system developed from the prognosticating markers may aid in predicting the outcome of Babesia gibsoni infection on the day of presentation itself enabling intensive care for those animals with a cut-off score more than 0.141.

Etiology and prognosis for dogs with abnormal blood glucose concentrations evaluated in an emergency room

OBJECTIVE

To determine the prevalence of glucose abnormalities in nondiabetic dogs presenting to a veterinary emergency room (ER) and their association with underlying disease processes, previous glucocorticoid administration, and overall mortality.

DESIGN

Single-center, retrospective study from January 2013 to December 2014.

SETTING

University Teaching Hospital.

ANIMALS

A total of 660 dogs presenting to an ER with a blood glucose concentration measured within 6 hours of presentation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Medical records from dogs with a blood glucose concentration measured within 6 hours of hospital admission were reviewed. Medications administered prior to blood sampling, the presence of shock, final clinical diagnosis, and survival were recorded. Hypoglycemia and hyperglycemia were defined as a blood glucose <4.4 mmol/L (80 mg/dL) and >6.7 mmol/L (120 mg/dL), respectively. Diabetic patients were removed from analysis. Hyperglycemia was found in 40.1% of dogs, whereas hypoglycemia was present in 9.0%. Hyperglycemia was most often associated with gastrointestinal disease, trauma, neoplasia, and respiratory disease. The most common diseases associated with hypoglycemia were sepsis, gastrointestinal disease, and neoplasia. Dogs in shock or with hyperlactatemia had higher blood glucose values than dogs with normal perfusion and plasma lactate concentrations (P = 0.016 and P < 0.0001, respectively). Mortality was higher in dogs with hyperglycemia (33.2%, P = 0.03) or hypoglycemia (44.6%, P = 0.0024) compared to those with normoglycemia (24.9%).

CONCLUSION

Dysglycemia in nondiabetic dogs evaluated in an ER was associated with a higher mortality rate than dogs in the same population with normoglycemia. Hyperglycemia in this population was common and may represent a stress response.

Prognostic indicators in cats with septic peritonitis (2002-2015): 83 cases

OBJECTIVE

To identify physical exam findings, clinicopathological parameters, time to surgery, empirical antimicrobial use, and culture results that could be associated with outcome in cats with septic peritonitis (SP).

DESIGN

Retrospective cohort study of cats from 2002 to 2015.

SETTING

Four university teaching hospitals.

ANIMALS

Eighty-three cats diagnosed with SP by cytology or culture.

INTERVENTIONS

None MEASUREMENTS AND MAIN RESULTS: Fifty-eight cats survived to discharge (69.9%); 1 cat was euthanized in surgery; 20 were euthanized postoperatively; 4 cats suffered cardiac arrest after surgery. The most common etiology of SP was secondary SP due to gastrointestinal perforation (49.4%), followed by primary SP (22.3%). Mean blood glucose concentration was significantly different between survivors and nonsurvivors (P = 0.006). Cats that received appropriate empirical antibiotic therapy were 4.4 times more likely to survive than cats that did not receive appropriate antibiotics (P = 0.018).

CONCLUSIONS

As previously documented, SP secondary to gastrointestinal leakage was the most common etiology. In this population, cats with a higher blood glucose concentration on presentation had a worse prognosis. Cats that received appropriate empirical antimicrobial therapy were more likely to survive.

Utility of admission lactate concentration, lactate variables, and shock index in outcome assessment in dogs diagnosed with shock

OBJECTIVE

To determine whether admission venous plasma lactate concentration, calculated lactate variables, or shock index (SI) could discriminate hospital survivors from nonsurvivors in dogs admitted with shock.

DESIGN

Prospective investigation performed over a 19-month period.

SETTING

Large urban private teaching hospital.

ANIMALS

Twenty-three dogs consecutively admitted to the ICU from January 2008 to July 2009 with initial peripheral venous plasma lactate concentration >2 mmol/L (18.0 mg/dL) and clinical and hemodynamic parameters consistent with shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Heart rate, systolic blood pressure, and venous plasma lactate concentrations were serially recorded at predefined time points and used to calculate SI (SI = heart rate/systolic blood pressure) and lactate variables, including lactime (time lactate > 2.0 mmol/L), lactate clearance ([lactate_initial - lactate_delayed ]/lactate_initial × 100), and LAC_AREA (area under the lactate concentration versus time curve). Primary outcome was survival to discharge. Overall survival rate was 61%. Admission venous plasma lactate concentration did not differ between groups (P = 0.2). Lactime was shorter in survivors versus nonsurvivors (P = 0.02). Lactate clearance at 1, 10, 16, 24, and 36 hours, and final lactate clearance were greater in survivors versus nonsurvivors (P < 0.05). LAC_AREA at time intervals 0-1, 1-4, 4-10, 10-16, 16-24, 24-30, and 30-36 hours was larger in nonsurvivors versus survivors (P < 0.05). Total LAC_AREA did not differ between groups (P = 0.09). Admission SI and time to normalize SI (SI < 0.9) were not different between survivors and nonsurvivors (P > 0.05).

CONCLUSIONS

While admission venous plasma lactate concentration could not discriminate between hospital survivors and nonsurvivors, lactate variables showed clinical utility to predict outcome in dogs with shock. Further studies are needed to determine SI reference ranges and optimal SI cut-off values to improve its prognostic ability in sick dogs.

A clinical and pathological description of 320 cases of naturally acquired Babesia rossi infection in dogs

Babesia rossi causes the most severe clinical disease in dogs of all the babesia parasites. We included 320 naturally-infected dogs that presented for care at the Onderstepoort Veterinary Academic Hospital between 2006 and 2016. All dogs had mono-infections confirmed by multiplex PCR. The data allowed more accurate clinical classification of the disease and identified parameters that were associated with disease severity and death. Odds ratios for dying were significant (P < 0.05) for increased band neutrophil count, collapse at presentation; presence of cerebral signs; hypoglycaemia; hyperlactatemia; high urea, high creatinine; hyperbilirubinaemia; hypercortisolaemia; and hypothyroxinaemia. Joint component analysis confirmed that the variables with significant odds ratios grouped together with death. Yet, multivariate logistic regression was unable to identify a group of significant independent predictors of death. Receiver Operator Characteristic curves indicated that low total thyroid hormone, high bilirubin, high serum urea and high cortisol concentrations were the variables with the highest sensitivity and specificity for death. These data provide both the clinician and researcher with a set of easily-measured laboratory and clinical assessments to classify cases into those that are uncomplicated and those that are complicated. The disease is complex and multisystemic and probably involves mechanisms more proximal in the pathogenesis than those that have been evaluated.

Canine babesiosis among working dogs of organised kennels in India: A comprehensive haematological, biochemical, clinicopathological and molecular epidemiological multiregional study

•

First holistic study on canine babesiosis among working dogs from India.

•

B. gibsoni babesiosis is posing a diagnostic & therapeutic challenge in this country.

•

Atypical babesiosis (MODS, DIC) are being maidenly documented from this country.

•

Simple PCR assay results were statistically found to be significantly false negative.

•

Nested PCR assay to be relied upon as screening and for epidemiological studies.

Canine babesiosis is a serious disease among tick-borne haemoprotozoan diseases, globally. The present study was envisaged for carrying out thorough investigation of the disease among working dogs of organised kennels situated in different agro-climatic zones of India as comprehensive understanding of the disease from this country was pertinently lacking. During the study period of three years (2012–2014), 330 dogs suspected for babesiosis were examined for clinicopathology by their physical examination, haematological and biochemical parameters estimation, while the detection of apicomplexan parasites was confirmed by using various diagnostic techniques i.e. by conventional microscopy, by two different Babesia specific 18S rRNA based PCR protocols (conventional/simple PCR and nested PCR assays) followed by sequencing of obtained PCR amplicons for Babsesia spp. identification. Out of 330 clinical cases screened 5.15% (17/330), 9.09% (30/330) and 15.45% (51/330) were found to be positive in microscopic examination, simple- and nested- PCR assay, respectively. Comparative statistical analyses of these diagnostic assay results revealed that significant difference exists among the three diagnostic methodologies and thus it is recommended that the nested PCR technique be relied upon as a screening molecular assay and also for epidemiological studies of the disease in this country. Phylogenetic analysis based on 18S rRNA depicted the monophyletic nature and clonal expansion among all the B. gibsoni, under study. Sequencing results of PCR amplicons revealed that B. gibsoni has predominantly established itself over B. vogeli as former was incriminated in 47 cases while latter was confirmed in only four animals. Based on the clinical severity, these 51 affected animals were classified into three main groups’ of 17 animals each viz., apparently healthy-, simple or uncomplicated babesiosis- and atypical or complicated babesiosis- group. Haematological and biochemical profiling of these dogs confirmed the characteristics findings of infection by both the Babesia spp. It was observed that the infection by small form of Babesia (B. gibsoni) is posing a significant therapeutic challenge and chemosterilization by commonly prescribed anti-protozoal drugs was not achieved as clinical relapses were often observed. The clinical signs, sequence based confirmation and severity of the infection suggested that there is a positive selection of B. gibsoni (smaller form) over B. vogeli (larger form) in this country and raises serious concerns as prognosis in former is considered to be poor compared to latter. Thus, these findings have opened new paradigms for planning of pragmatic control strategies against this emerging canine health problem.

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.

Pathophysiology and aetiology of hypoglycaemic crises

Hypoglycaemia is a common, life-threatening complication that occurs as a component of a wide variety of disease processes. Despite its frequent occurrence, information concerning the aetiology, characteristics and outcomes of hypoglycaemic crises in veterinary medicine is limited. This review summarises the current understanding of the pathophysiology of hypoglycaemia, the body's counter-regulatory response, underlying aetiologies, diagnosis and treatment. Disease mechanisms are discussed and published evidence in veterinary literature regarding prognostic indicators, prevalence, diagnosis and treatment is examined for hypoglycaemia-related disease processes including insulinoma, glucose-lowering toxins and medications.

A flow cytometric assessment of the lymphocyte immunophenotypes in dogs naturally infected with Babesia rossi

Immunity to Babesia infection requires both innate and acquired responses, including cell mediated- and humoral responses. The aims of this study were to investigate the variation in selected peripheral blood lymphocyte phenotypes in dogs with virulent babesiosis at presentation and over time after treatment, and to determine whether these were correlated with the severity of clinical signs. Forty-four dogs naturally infected with B. rossi were studied and 5 healthy dogs were included as controls. Blood samples were collected from the jugular vein at admission, prior to any treatment, and at 24h and 48-72h. Leukocytes were incubated with canine specific, fluorochrome conjugated anti-CD3, anti-CD4, anti-CD8, and anti-B cell markers. Babesia-infected dogs were divided into complicated or uncomplicated groups on clinical grounds and in-house laboratory assays. The percentage CD3⁺ lymphocytes in the complicated group was lower compared to the controls (P=0.014) and uncomplicated group (P=0.007). The percentage CD4⁺ T lymphocytes in the complicated group was lower compared to the controls (P=0.027) and uncomplicated group (P=0.014). Both the complicated as well as the uncomplicated groups expressed a lower percentage CD8⁺ T lymphocytes compared to the control group (P<0.001 and P=0.005, respectively). The percentage B lymphocytes was higher in the complicated group at 48-72h. These findings could indicate the presence of a functional immune suppression secondary to increased apoptosis or redistribution of effector lymphocytes and/or a combination of other immune modulatory mechanisms induced by B. rossi infection.

Evaluation of the Lactate Plus monitor for plasma lactate concentration measurement in dogs

OBJECTIVE

To compare the Lactate Plus handheld monitor to a reference blood gas analyzer for determining plasma lactate concentrations in canine whole blood.

DESIGN

Prospective observational study.

SETTING

University teaching hospital.

ANIMALS

Ninety-four dogs hospitalized or admitted through the emergency service provided 125 blood samples. Only dogs that required a venous or arterial blood gas evaluation as a part of their diagnostic assessment or ongoing management were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Canine whole blood samples were assayed for plasma lactate concentration with a reference blood gas analyzer and the Lactate Plus monitor. Correlation and Bland-Altman analyses were used to compare results between the 2 methods. A subset of blood samples was repeatedly analyzed with the Lactate Plus to assess monitor precision. Plasma lactate measurements from the Lactate Plus monitor showed excellent correlation with those from the reference analyzer (ρ = 0.98, P < 0.0001). Bland-Altman analysis revealed a small bias (0.1296). Agreement between the 2 methods was less consistent for lactate concentrations >5 mmol/L. The coefficient of variation ranged from 0-26.2% (median, 3.7%) and was <15% for 50/53 samples.

CONCLUSIONS

The Lactate Plus provides a fast and affordable method to measure plasma lactate concentration in dogs. Results showed excellent agreement with the reference analyzer and precision of the instrument was acceptable.

Update: Clinical Use of Plasma Lactate

Lactate is an essential, versatile metabolic fuel in cellular bioenergetics. In human emergency and critical care, lactate is used as a biomarker and therapeutic endpoint and evidence is growing in veterinary medicine supporting its clinical utility. Lactate production is a protective response providing ongoing cellular energy during tissue hypoperfusion or hypoxia and mitigating acidosis. Hence, hyperlactatemia is closely associated with disease severity but it is an epiphenomenon as the body attempts to protect itself. This article reviews lactate biochemistry, kinetics, pathophysiology, some practical aspects of measuring lactate, as well as its use in diagnosis, prognosis, and monitoring.

Reliability of clinical monitoring for the diagnosis of babesiosis in dogs in Nigeria

Babesiosis accounts for a high percentage of hospital cases in canines in Africa, with about 40% mortality in the cases presented. In Nigeria, records show an estimated 30% annual morbidity when diagnosis is largely based on clinical and laboratory findings. This study monitored clinical indices associated with canine babesiosis. One hundred and three babesiosis-suspected dogs were selected on the basis of clinical signs of anorexia, fever, presence of ticks, and enlarged lymph nodes or spleen when clinical parameters were recorded at the time of presentation. Parasite detection was done using thin blood smears; that is, the presence of Babesia merozoites was compared between capillary and cephalic blood. Blood was also assayed for hematology and blood chemistry using automated blood analyzers. The babesiosis-infected dogs’ outcome was monitored. Data obtained were analyzed using chi-square test, analysis of variance, and Pearson’s correlation. Results based on thin blood smears showed that 61.1% of the dogs were positive for Babesia species. Breed disposition, sex, and age did not significantly influence the incidence of Babesia canis, while mean rectal temperatures did not differ significantly between the cases (P>0.05). Heart rate and pulse rates of Babesia-positive dogs were significantly (P<0.05) higher than those that were negative. The packed cell volume between the cases was not significantly different, with the values in the positive and negative case obtained being 26.4% ±11.26% and 31.6%±11.9%, respectively, with a range of 6% to 50% and 10% to 47% observed, respectively. Normal leukogram was also observed in 62% of the Babesia-positive cases while 22.2% and 15.8% had leukocytosis and leukopenia, respectively. Most of the positive cases whose results were based on thin blood smear were treated with 5% oxytetracycline for 5 days and fully recovered. Pearson’s correlation was used to give relationship in the observed data. This study concluded that clinical indices are not reliable markers in the diagnosis of canine babesiosis.

Hyperlactatemia and serial lactate measurements in sick cats

OBJECTIVES

To document the incidence of hyperlactatemia in sick cats hospitalized for emergency care and to evaluate the prognostic utility of serial lactate measurements in cats with hyperlactatemia.

DESIGN

Prospective observational study over a 10-month period (July 2010-May 2011).

SETTING

Private veterinary referral center with 24-hour hospital care.

ANIMALS

One hundred and twenty-three privately owned cats admitted to a private referral center.

INTERVENTIONS

Blood was collected by direct venipuncture from the jugular or medial saphenous vein at the time of hospital admission and at 6 and 24 hours following admission.

MEASUREMENTS AND MAIN RESULTS

The median plasma lactate concentration for all cats at admission (T0) was 1.89 mmol/L (17.0 mg/dL) (range: 0.3-12.48). Twenty-three percent (28/123) of cats admitted were hyperlactatemic (ie, >2.87 mmol/L; >25.86 mg/dL) upon admission. Lactate concentration at presentation and serial lactate measurements were not found to be related with survival to discharge or correlated with duration of hospitalization. The overall survival rate of all cats in this study was 81%.

CONCLUSIONS

This study demonstrated that the incidence of hyperlactatemia in sick cats being admitted for hospitalization in a private referral center was 23%, and that lactate concentration on admission and serial lactate measurements over time were not prognostic in this group of hospitalized cats. Future studies are needed to evaluate the prognostic utility of lactate and serial lactate measurements in specific disease states and in a larger population of critically ill cats.

Point of Care Measurement of Lactate

Lactate is generated as a consequence of anaerobic glycolysis by all tissues of the body. Increased l-lactate, the isoform produced by most mammals, reflects increased anaerobic metabolism secondary to tissue hypoperfusion or tissue hypoxia in most clinical situations, and is called type A lactic acidosis. The utility of lactate measurement and serial lactate monitoring in veterinary patients has been demonstrated in multiple studies. Blood lactate concentration is significantly elevated in many disease processes including septic peritonitis, immune-mediated hemolytic anemia, Babesiosis, trauma, gastric dilation and volvulus, and intracranial disease. Lactate clearance can be used to assess response to fluid therapy, cardiovascular therapeutics, and blood product transfusion in patients affected by type A lactic acidosis. Lactate concentration in peritoneal, pericardial, and synovial fluid can also be used as a diagnostic tool. Point of care analyzers such as the Lactate Pro, Lactate Scout, Accutrend, iSTAT, and Lactate Plus have been shown to be accurate lactate measurement instruments in small animal patients.

Prognostic Markers in Acute Babesia canis Infections

Background

Canine babesiosis, caused by Babesia canis, is a prevalent and clinically relevant disease in Europe. Severe acute babesiosis is characterized by a high mortality but prognosis is not always correlated with clinical signs nor with the level of parasitemia.

Objective

This study evaluated prognostic markers associated with poor outcomes in acute Babesia canis infections.

Animals and Methods

We compared the results of routine laboratory profiles, hand‐held lactate and glucose analyzer, and the acute phase response in 2 groups of naturally infected dogs (7 survivors and 8 nonsurvivors). Samples were collected at the time of first admission and before any treatment. Subsequently, the course of prognostic markers was followed in 3 dogs experimentally inoculated with B. canis.

Results

Nonsurvivors showed significantly higher concentrations of lactate, triglycerides and phosphate and lower hematocrit, leukocyte counts, total serum protein concentrations, and thrombocyte counts when compared to survivors. All nonsurvivors (8/8) had hyperlactatemia, whereas most survivors (6/7) had values within the reference range. All survivors had leucocyte counts within the reference range, unlike the nonsurvivors, which showed leukopenia. During the course of acute babesiosis, the variables serum lactate, triglyceride, and phosphate concentrations, and thrombocyte count only exceeded a prognostic threshold during acute crisis.

Conclusions and clinical importance

Poor outcome in acute B. canis infection is indicated by changes in the laboratory profile. Intensive care should be considered for dogs presenting with moderate anemia, severe thrombocytopenia, mild to moderate leukopenia, hyperlactatemia, moderately increased serum phosphate, and triglyceride concentrations, and moderately decreased total serum protein concentrations.

Plasma lactate concentration as a prognostic biomarker in dogs with gastric dilation and volvulus

Initial and serial plasma lactate concentrations can be used to guide decision making in individual dogs with GDV but care is necessary in phrasing conversations with owners. Published data suggests that survival is more likely and the chance of complications less in dogs with an initial plasma lactate of <4 mmol/L. An initial lactate >6 mmol/L makes gastric necrosis and greater expense more likely. However, because of the overlap between groups and the good overall survival rates, exploratory laparotomy should always be recommended irrespective of the plasma lactate concentration. Falls in plasma lactate of greater than ~40% after fluid resuscitation are likely to indicate better survival. If the initial plasma lactate concentration is moderately to severely increased (5->10 mmol/L) and a sustained increase in plasma lactate occurs after fluid resuscitation, the cause should be aggressively pursued. Many dogs with persistent hyperlactatemia over 24-48 hours do not survive.

Plasma lactate concentrations in septic peritonitis: A retrospective study of 83 dogs (2007-2012)

OBJECTIVE

To determine if absolute plasma lactate concentration or lactate clearance in dogs with septic peritonitis is associated with morbidity or mortality.

DESIGN

Retrospective cohort study from 2007 to 2012.

SETTING

University teaching hospital.

ANIMALS

Eighty-three dogs with septic peritonitis were included. Patients had at least 1 plasma lactate measurement during the course of the hospitalization.

RESULTS

Sixty-four percent of the patients survived to discharge, 22% were euthanized, and 14% died during hospitalization. Plasma lactate concentration >2.5 mmol/L on admission (29% of the patients) was associated with mortality (P = 0.001). Median admission plasma lactate concentration (n = 81) was significantly different between nonsurvivors (2.5 mmol/L, range 0.5-8.4) and survivors (1.4 mmol/L, range 0.5-9.7; P = 0.007). Admission plasma lactate concentration >4 mmol/L yielded a sensitivity of 36% and a specificity of 92% for nonsurvival. The inability to normalize plasma lactate concentration within 6 hours of admission (n = 10/24) yielded a sensitivity of 76% and specificity of 100% for nonsurvival. Postoperative hyperlactatemia (plasma lactate concentration >2 mmol/L; n = 18/76) had a sensitivity of 46% and specificity of 88% for nonsurvival. Persistent postoperative hyperlactatemia (n = 11/18) had a sensitivity of 92% and a specificity of 100% for nonsurvival. Lactate clearance less than 21% at 6 hours (n = 20) had a sensitivity of 54% and specificity of 91% for nonsurvival. Lactate clearance less than 42% at 12 hours (n = 18) had a sensitivity of 82% and a specificity of 100% for nonsurvival.

CONCLUSIONS

Admission plasma lactate concentration and lactate clearance were good prognostic indicators in dogs with septic peritonitis.

A pilot comparison of limited versus large fluid volume resuscitation in canine spontaneous hemoperitoneum

Treatment for hemorrhagic shock secondary to a spontaneous hemoperitoneum includes restoration of IV volume and surgical control of hemorrhage. This study was designed to determine if limited fluid volume resuscitation (LFVR) with hypertonic saline (HS) and hyperoncotic fluids (hydroxyethylstarch [HES]) results in more rapid cardiovascular stabilization in dogs with spontaneous hemoperitoneum versus conventional resuscitation (CR) with large volume resuscitation. Eighteen client-owned dogs presenting in hemorrhagic shock with a spontaneous hemoperitoneum were enrolled. Dogs were randomized to be fluid resuscitated with up to 90 mL/kg of an isotonic crystalloid (CR group) or up to 8 mL/kg of 7.2% Na chloride (i.e., HS) combined with up to 10 mL/kg of 6% HES. Measurements of vital signs, lactate, packed cell volume (PCV), total solids (TS), and blood pressure were made at standard time points. The primary end point was time to stabilization of hemodynamic parameters (measured in min). Dogs in the LFVR group achieved hemodynamic stabilization significantly faster (20 min; range, 10-25 min) than those in the CR group (35 min; range, 15-50 min; P = .027). Future studies are warranted to further investigate potential benefits associated with LFVR in dogs with spontaneous hemoperitoneum.

Comparison of Two Portable Lactate Meters in Dogs

The objective of this study was to compare two portable lactate analyzers for testing canine patients in a clinical setting with a previously accepted methodology for measuring plasma lactate. Between Jan 1, 2005 and Jun 1, 2006, all samples were analyzed using two different portable analyzers (devices A and B), and 86 of those samples were also analyzed by a reference laboratory (REF). The concordance correlation coefficient (CCC) for device A and the REF was 0.949 (95% confidence interval [95% CI], 0.923–0.966). For device B and REF, the CCC was 0.990 (95% CI, 0.985–0.993). Only 8 of 85 samples (9.4%) exceeded a relative difference of 20% for device B (note that 1 of the 86 samples was not included because the lactate level fell below the detectable limit of device B), but 48 of 85 samples (56.5%) exceeded a relative difference of 20% for device A. Both portable lactate analyzers appeared to be effective in detecting clinically significant elevations in plasma lactate compared with the REF but device B had better agreement. A positive correlation among all three analyzers existed; however, the analyzers do not yield directly interchangeable results.

The association of blood lactate concentration with outcome in dogs with idiopathic immune-mediated hemolytic anemia: 173 cases (2003-2006)

OBJECTIVE

To determine the association of blood lactate with outcome and response to transfusion therapy in dogs with idiopathic immune-mediated hemolytic anemia (IMHA).

DESIGN

Retrospective study.

SETTING

Urban veterinary small animal emergency hospital.

ANIMALS

One hundred and seventy-three client-owned dogs with IMHA.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Serial blood lactate concentration, therapeutic interventions, and outcome were recorded. Nonsurvivors were defined as those that died or were euthanized. One hundred and thirty-three dogs (77%) survived, 35 (20%) were euthanized, and 5 (3%) died. One hundred forty-five dogs (84%; 145/173) had a lactate concentration above the laboratory reference interval [0.46-2.31 mmol/L] on presentation. Blood lactate at presentation was higher in the nonsurvivors (median 4.8 mmol/L; 0.5-13.6) compared with survivors (median 2.9 mmol/L; 0.3-13.2) (P<0.01). All dogs presenting with hyperlactatemia that normalized (<2.0 mmol/L) within 6 hours of admission survived, whereas, 71% of dogs that had a persistent hyperlactatemia at 6 hours survived (P=0.034). Lactate was positively correlated with age, BUN, and alkaline phosphatase, and inversely correlated with PCV. Receiver operating curve analysis for lactate concentration at admission as a test for outcome had an area under the curve of 0.69 with an optimal lactate cutoff concentration of 4.4 mmol/L correctly predicting outcome 73% of the time (sensitivity 60%, specificity 77%).

CONCLUSIONS

Lactate concentration at presentation was significantly higher in nonsurvivors than survivors. Lactate was significantly correlated with previously reported outcome variables but lactate concentration at admission, as a predictor for outcome was less than optimal. However, serial lactate concentration measurements may be more predictive as patients with persistent hyperlactatemia 6 hours after admission were less likely to survive. Prospective studies evaluating serial lactate concentration while controlling for other variables may provide further insight into lactate measurement as a prognostic indicator in animals with IMHA.

Clinical management of canine babesiosis

OBJECTIVE

To review and summarize current information regarding epidemiology, pathogenesis, and pathophysiology leading to the various clinical syndromes associated with canine babesiosis. Diagnosis, treatment, preventative strategies, and zoonotic implications are discussed.

ETIOLOGY

Babesiosis is caused by hemoprotozoa of the genus Babesia. Numerous species of Babesia exist worldwide. An increased incidence of babesiosis is described, especially in North America. The babesial organism spends the majority of its life cycle within the erythrocyte of the definitive host, resulting in hemolysis, with or without systemic complications.

DIAGNOSIS

Definitive diagnosis depends on direct visualization of the organism on blood smear or polymerase chain reaction. A positive serologic antibody test indicates exposure with or without active infection.

THERAPY

Antiprotozoal drugs, antimicrobials, and supportive care are the mainstays of babesiosis therapy.

PROGNOSIS

Prognosis depends on the severity of disease, which in turn depends on both organism and host factors. Clinical syndromes associated with a poorer prognosis include red biliary syndrome, acute renal failure, acute respiratory distress syndrome, neurologic dysfunction, acute pancreatitis, cardiac dysfunction, and hypoglycemia.

A prospective, randomized comparison of Oxyglobin (HB-200) and packed red blood cell transfusion for canine babesiosis

OBJECTIVE

To establish the efficacy of Oxyglobin (HB-200) in canine babesiosis and compare it to standard therapy, packed red blood cell transfusion (pRBCT) with respect to improvements in specific parameters of blood gas, acid-base, blood pressure, and subjective evaluations.

DESIGN

Prospective, randomized, clinical trial.

SETTING

Onderstepoort Veterinary Academic Hospital.

ANIMALS

Twelve dogs (8-25 kg) naturally infected with Babesia rossi and a hematocrit of 0.1-0.2 L/L (10-20%).

INTERVENTIONS

Treatment groups were randomized to receive either 20 mL/kg of Oxyglobin or pRBCT over 4 hours via a central venous catheter. Transfusions were followed by lactated Ringer's solution infusion. Rectal temperature, femoral arterial and mixed venous blood sampling, oscillometric blood pressure, and subjective assessment of patient status (habitus), and appetite were performed at time points 0, 1, 4, 8, 24, 48, and 72 hours.

MAIN RESULTS

Dogs presented with a hypoalbuminemic alkalosis; hyperchloremic, dilutional acidosis; normotensive tachycardia; pyrexia; depression; and anorexia. Both treatments produced similar results, with the exception of significant differences in pH (4 h); PCO(2) (4 h); hemoglobin (8 h, 24 h); mean arterial pressure (48 h); albumin (4 h, 8 h); habitus (8 h, 48 h); and appetite (24 h). Arterial O(2) content was higher for pRBCT than Oxyglobin at 72 hours, but central venous PO(2) did not differ between groups or over time and was consistently subnormal.

CONCLUSIONS

Oxyglobin provides similar overall improvements to pRBCT in dogs with anemia from babesiosis, with respect to blood gas, acid-base and blood pressure, although patients receiving packed cells tended to have more rapid normalization of habitus and appetite.

Serial blood lactate concentrations in systemically ill dogs

BACKGROUND

Lactate concentration often is quantified in systemically ill dogs and interpreted based on human data. To our knowledge, there are no published clinical studies evaluating serial lactate concentrations as a prognostic indicator in ill dogs.

OBJECTIVES

Our objective was to perform a prospective study, using multivariate analysis, to determine whether serial lactate concentrations were associated with outcome in ill dogs requiring intravenous fluids.

METHODS

Eighty sick dogs had lactate concentrations evaluated, using an analyzer that measures lactate in the plasma fraction of heparinized whole blood, at 0 hours and 6 hours after initiation of treatment. Severity of illness and outcome (survivor, nonsurvivor) were determined by reviewing the patient's record 2 weeks after admission. Lactate concentrations, age, body weight, gender, and severity of illness were evaluated using multivariate analysis to determine their effects on outcome.

RESULTS

Dogs with lactate concentrations greater than the reference interval at 6 hours were 16 times (95% confidence interval = 2.32-112.71 times, P <.01) more likely not to survive compared to dogs with lactate concentrations within the reference interval. Lactate concentrations above the reference interval at 0 hours were not significantly related to outcome. However, hyperlactatemia that did not improve by > or = 50% within 6 hours was significantly associated with mortality (P = .024).

CONCLUSION

Dogs with a lactate concentration higher than the reference interval at 6 hours were more likely not to survive. These results indicate an association between lactate concentration and outcome and emphasize the importance of serial lactate concentrations in evaluating prognosis.

Evaluation of the Accutrend for lactate measurement in dogs

BACKGROUND

Lactate concentrations are increasingly quantified in dogs using point-of-care instruments, but often without canine-specific method evaluation and instrument-specific reference intervals.

OBJECTIVES

The objectives of this study were to 1) determine the precision of the Accutrend (Roche Diagnostics) for lactate determination in dogs, 2) determine the accuracy of the Accutrend using the Rapidlab 865 (Bayer Diagnostics) as the reference method, and 3) establish and compare reference intervals for lactate concentration in clinically healthy dogs for both instruments.

METHODS

Precision was evaluated using low and high control materials, and variable (1 drop) and fixed (25 microL) sample volumes. Accuracy was determined by comparing lactate concentrations obtained with the Accutrend with those from the Rapidlab 865 in 273 heparinized canine jugular venous blood samples from 100 clinically healthy dogs and 107 systemically ill dogs (173 samples). Lactate reference intervals were established for both analyzers using data from the 100 clinically healthy dogs.

RESULTS

The precision of the Accutrend was good (coefficients of variation, < or = 5.3%) for 25-microL samples but not when a drop was used. Lactate concentrations obtained on the Accutrend correlated poorly with those from the Rapidlab 865 (r = 0.864, mean bias = 0.66 mmol/L, 95% confidence interval [CI] = 0.57-0.76 with 95% limits of agreement = -0.87 (lower limit, 95% CI = -1.03 to -0.71) and 2.20 (upper limit, 95% CI = 2.04 to 2.36). The reference interval for canine lactate concentration on the Accutrend was 1.2-3.1 mmol/L compared with 0.46-2.31 mmol/L on the Rapidlab.

CONCLUSION

Although precision was good with fixed sample volumes, blood lactate concentrations obtained on the Accutrend were significantly different than those on the Rapidlab 865, with systematic and random errors resulting in a positive bias. Further evaluation of the Accutrend is required before its use in dogs can be recommended.

Quantification of 13C pyruvate and 13C lactate in dog blood by reversed-phase liquid chromatography–electrospray ionization mass spectrometry after derivatization with 3-nitrophenylhydrazine

Injection of hyperpolarized (13)C-labelled pyruvate ((13)C pyruvate) is under evaluation as an agent for medical metabolic imaging by measuring formation of (13)C lactate using magnetic resonance spectroscopy of the (13)C nuclei. A quantitative method for analysis of these (13)C-labelled substances in dog blood was needed as part of the development of this agent and we here describe a liquid chromatography-mass spectrometry method for that purpose. Immediately after blood collection, the blood proteins were precipitated using methanol added internal standard ([U-(13)C]pyruvate and [U-(13)C]lactate). Prior to analysis, the compounds were derivatized using 3-nitrophenylhydrazine. Following separation on a Supelco Discovery HS C18 column, (13)C pyruvate and (13)C lactate were detected using negative electrospray ionization mass spectrometry. Calibration standards (4.5-4500 microM (13)C pyruvate and 9-9000 microM (13)C lactate) and added internal standard were used to make the calibration curves, which were fitted to a non-linear equation y=a+bx+cx(2) and weighted with a weighting factor of 1/y(2). The analytical lower limit of quantification of (13)C pyruvate and (13)C lactate was 4.5 and 9 microM, respectively. The total precision of the method was below 9.2% for (13)C pyruvate and below 5.8% for (13)C lactate. The accuracy of the method showed a relative error less than 2.4% for (13)C pyruvate and less than 6.3% for (13)C lactate. The recoveries were in the range 93-115% for (13)C pyruvate and 70-111% for (13)C lactate. Both substances were stable in protein-free supernatant when stored for up to 3 weeks in a -20 degrees C freezer, during three freeze/thaw cycles, and when stored in an autosampler for at least 30 h.

Capillary and venous Babesia canis rossi parasitaemias and their association with outcome of infection and circulatory compromise

This observational study of 100 dogs naturally infected with Babesia canis rossi determined whether severity of parasitaemia was associated with outcome of infection and documented the relative distribution of parasitised red blood cells (pRBC) in capillary and venous circulation. The association between increased parasitaemias and outcome with a clinically compromised circulation was also investigated. Outcome was defined as either hospitalisation with death, or hospitalisation with eventual recovery or treatment as an outpatient. Dogs were enrolled if large babesias were found on stained thin capillary blood smears made from an ear prick. Thin venous smears were prepared from jugular or cephalic blood. Parasitaemias were manually counted and expressed as the percent pRBC. Ten dogs died, 50 recovered after hospitalisation and 40 were treated as outpatients. Venous sampling site did not affect venous parasitaemia (P=0.6). Both capillary and venous parasitaemias of dogs that died were significantly higher than those of dogs that recovered after hospitalisation (P=0.002) and dogs that were treated as outpatients (P<0.0001). When assessing the whole group, capillary parasitaemia (median 0.61%, range <0.05-71.6%, interquartile range (IQR) 0.22-3.75%) was significantly higher than venous parasitaemia (median 0.14%, range 0-30.6%, IQR 0.046-0.52%) with P<0.0001. The 21 dogs with a clinically compromised circulation were more likely to die (P<0.0001) and had significantly higher capillary (median 5.98%, range 0.09-71.6%, IQR 2.44-19.41%) and venous (median 2.81%, range <0.05-30.6%, IQR 0.17-9.03%) parasitaemias than the 79 dogs with a clinically normal circulation (capillary median parasitaemia 0.38%, range <0.05-12.87%, IQR 0.16-1.42%; venous median parasitaemia 0.096%, range 0-6.13%, IQR <0.05-0.33%; P<0.0001). This study shows that high parasitaemia is significantly associated with death in B c rossi infected dogs. The previous clinical suspicion that capillary parasitaemias are usually higher than venous parasitaemias is confirmed. Thus capillary samples are the most appropriate diagnostic samples. Prior observations that a clinically compromised circulation is associated with death are confirmed. Despite the highly significant association between compromised circulation and higher parasitaemia, it is thought unlikely that parasite burden is the sole trigger for circulatory collapse.

The South African form of severe and complicated canine babesiosis: clinical advances 1994-2004

Babesia (canis) rossi infection is common in dogs in South Africa, and frequently causes severe, life-threatening disease. Acidemia, persistent hyperlactatemia, hemoconcentration, elevated creatinine, cerebral babesiosis, pulmonary edema and pancreatitis are all associated with mortality rates above 30%, compared with overall mortality of 12% in admitted cases. Although half the admitted cases are severely anemic, hemoconcentration is associated with far higher mortality. Cerebral babesiosis is uncommon, but carries a poor prognosis. The pathological mechanism has been suggested to be endothelial cell damage and necrosis, followed by segmental microvascular necrosis with perivascular edema and hemorrhage. Renal involvement in babesiosis resembles the functional renal failure of sepsis. Hypotension is common, and other cardiovascular disturbances have been documented. Cerebellar ataxia, rhabdomyolysis and pancreatitis are recently identified complications. While the previous categorization into "severe" (life-threatening anemia) and "complicated" (complications not directly attributable to anemia) disease has proved useful, the distinction is artificial and probably unnecessary. An updated approach to classification is suggested, aimed at grouping animals by severity and prognosis, and using simple measures, such as clinical collapse and abnormal breathing, as much as possible. Although inflammatory mechanisms are undoubtedly important in the pathophysiology of babesiosis, there can be little doubt that tissue hypoxia plays a major role in the disease process.