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.     

The accuracy of the Lactate Pro hand-held analyser to determine blood lactate in healthy dogs

OBJECTIVES: The objective of this study was to determine the accuracy of the Lactate Pro hand-held analyser in measuring blood lactate levels. METHODS: Blood was drawn from 15 healthy dogs into five tubes containing Na-EDTA. Lactate was measured immediately using the Lactate Pro analyser and a laboratory reference method. Further samples were analysed 120, 240, 480 and 1440 minutes later to artificially increase the lactate levels. Lactate was measured in blood samples of 60 healthy dogs using the Lactate Pro analyser to determine the reference interval of lactate concentration in normal dogs. RESULTS: The correlation between the lactate concentration measured with the Lactate Pro analyser and the reference method was high. Lactate levels were lower when measured with the hand-held analyser than with the traditional laboratory determination. The reference interval for blood lactate concentrations in healthy dogs established by the Lactate Pro analyser was from the detection limit (0.8 mmol/l) up to 3.3 mmol/l. CLINICAL SIGNIFICANCE: The Lactate Pro analyser provides quick and reliable measurements of blood lactate in dogs with blood lactate levels up to 10 mmol/l. Because of its small sample size, this analyser will be particularly appropriate for use in small animal intensive care.     

Serial plasma lactate concentrations in 68 puppies aged 4 to 80 days

Objective: To determine a reference range for venous blood lactate concentrations in healthy neonatal dogs. Design: A prospective cohort study. Setting: All work was conducted at the College of Veterinary Medicine, Texas A&M University. Animals: Clinically healthy dogs: 68 puppies and 30 adults. Measurements and main results: A blood sample was collected from each puppy into lithium heparin via jugular venipuncture at 4, 10, 16, 28, 70, and 80 days of age. A single venous sample was collected from each adult dog. Lactate concentration in each sample was measured immediately using an automated analyzer. Two hundred seventy‐seven blood samples were analyzed. Blood lactate concentrations of adult dogs were 1.80±0.84 mmol/L (mean±SD). Mean blood lactate concentrations of puppies were significantly higher at 4, 10, 16, and 28 days of age compared with those of adult dogs. The reference range for lactate concentration for puppies at 4 days of age was 1.07–6.59, and for the puppies from 10 to 28 days of age was 0.80–4.60. Conclusions: Assessment of perfusion can be challenging in neonates due to normal physiologic variation and small size. Measurement of lactate is rapid, minimally invasive, and has potential to be a useful marker of perfusion in neonatal dogs. However, lactate concentrations of neonatal dogs in this study were significantly higher than those of adult dogs. Reference ranges for venous lactate concentrations in adult dogs should not be used for puppies younger than 70 days of age.     

Prospective evaluation of clinically relevant type B hyperlactatemia in dogs with cancer

Background: Cancer is considered a cause of type B hyperlactatemia in dogs. However, studies evaluating cancer as a cause of clinically relevant type B hyperlactatemia (>2.5 mmol/L) are lacking. Cancer cells have a higher lactate production because of increased aerobic glycolysis, known as the “Warburg effect.” The mechanisms through which aerobic glycolysis occurs are not well elucidated, but neoplasia may cause type B hyperlactatemia via this process. Objectives: To determine if malignant tumors of dogs are associated with clinically relevant type B hyperlactatemia (>2.5 mmol/L). Animals: Thirty‐seven client‐owned dogs with malignant tumors: 22 with hematopoietic and 15 with solid tumors. Methods: Histology was used to confirm the diagnosis (cytology was considered adequate for diagnosis of lymphoma). Confounding conditions associated with hyperlactatemia were excluded. Lactate measurements were immediately performed on free‐flow jugular whole blood samples using the LactatePro analyzer. Results: All dogs had lactate concentrations <2.5 mmol/L. Mean blood lactate concentration was 1.09 mmol/L. Mean blood lactate concentrations for solid and hematopoietic tumors were 0.95 and 1.19 mmol/L, respectively. Dogs with lymphoma (n = 18) had a mean blood lactate concentration of 1.15 mmol/L. Conclusions: Malignant tumors were not considered a cause of clinically relevant type B hyperlactatemia. Therefore, cancer‐related type B hyperlactatemia in dogs is uncommon, and hyperlactatemia should prompt careful investigation for causes other than cancer.     

Metabolic and electrolyte disturbances in acute canine babesiosis.

Arterial blood pH, PCO2, bicarbonate, base excess/deficit, and lactate, as well as serum sodium, potassium, and chloride were measured in clinically normal dogs and in dogs with acute canine babesiosis. Metabolic acidosis developed in dogs with fatal as well as nonfatal Babesia canis infection. In the fatal group, the acidosis was uncompensated; among survivors, base deficit and blood lactate were significantly lower, and pH, PCO2, and bicarbonate values were significantly higher. Serum potassium values were significantly lower, and serum chloride values were significantly higher in dogs with acute babesiosis than in clinically normal dogs. The shock resulting from acute canine babesiosis is best viewed as anemic shock. Treatment should include an alkalizing agent, a blood transfusion, fluid therapy, and a babesicidal drug.     

Alterations in Carbohydrate Metabolism in Canine Lymphoma

Following an overnight fast, blood samples were obtained from 14 dogs with previously untreated lymphoma before and 5, 15, 30, 45, 60, and 90 minutes following an intravenous challenge with 500 mg/kg dextrose. Samples were assayed for glucose, lactate, and insulin concentrations and compared statistically with ten control dogs of similar weight and age undergoing an identical dextrose challenge. Dogs with lymphoma had similar glucose tolerance curves when compared with controls. Lactate concentrations were significantly higher (P less than 0.001) at baseline and all time periods of the glucose tolerance test in dogs with lymphoma when compared with controls. Rise in lactate concentrations over baseline levels in the first 30 minutes of the glucose tolerance test were significantly higher in dogs with lymphoma (P = 0.011). Insulin concentrations were significantly higher (P less than 0.001) at baseline and at the 5-, 45-, 60-, and 90-minute time periods of the glucose tolerance test in dogs with lymphoma. Rise in insulin concentrations over baseline in the first 5 minutes of the glucose tolerance test were also significantly greater in dogs with lymphoma (P = 0.021). These results indicate carbohydrate metabolism is altered in dogs with lymphoma. Many of these alterations parallel those observed in human patients suffering from cancer cachexia making canine lymphoma a potential model for further study of the pathogenesis and therapy of cancer cachexia.     

Glucose, lactate, and pyruvate concentrations in dogs with babesiosis

OBJECTIVE: To document changes in glucose, lactate, and pyruvate concentrations in dogs with severe or complicated babesiosis; assess relationships among glucose, lactate, and pyruvate concentrations in those dogs; and compare clinical and laboratory variables in dogs with and without hypoglycemia and hyperlactatemia. ANIMALS: 20 dogs with naturally developing severe or complicated babesiosis. PROCEDURE: Samples and measurements were obtained before treatment was initiated. Babesiosis was diagnosed by examination of blood smears. Arterial blood pressure measurement, parasite quantification, CBC count, serum biochemical analysis, urinalysis, venous blood gas analysis, and acid-base determination were performed. Glucose, lactate, and pyruvate concentrations were measured in samples of venous blood. RESULTS: We detected a significant negative correlation between glucose and lactate concentrations. Glucose, lactate, and pyruvate concentrations all differed significantly between dogs that died and those that survived. Three of 5 dogs that died had concurrent hypoglycemia, hyperlactatemia, and hyperpyruvatemia. Hypoglycemic dogs differed significantly from normoglycemic dogs with regard to lactate, urea, and bicarbonate concentrations; lactate-to-pyruvate ratio; percentage parasitemia; and PCO2. Dogs with hyperlactatemia differed significantly from normolactatemic dogs with regard to clinical collapse; alanine transaminase activity; concentrations of bilirubin, urea, creatinine, and bicarbonate; percentage parasitemia; and PCO2. CONCLUSIONS AND CLINICAL RELEVANCE: Abnormal carbohydrate metabolism is commonly evident in dogs with severe or complicated babesiosis and is often associated with changes in other clinical and laboratory variables. Significant differences were found between survivors and nonsurvivors. Hypoglycemia should be assessed and aggressively treated in dogs with babesiosis. Lactate concentration can be used as an indicator of disease severity.     

Retrospective Study: 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.     

Serum cortisol and thyroxine concentrations as predictors of death in critically ill puppies with parvoviral diarrhea

OBJECTIVE: To evaluate the role of adrenal and thyroid hormones in the prediction of death in a population of critically ill puppies with parvoviral diarrhea by measuring serial daily serum concentrations of cortisol and thyroxine. DESIGN: Prospective case-control study. ANIMALS: 57 critically ill puppies with parvoviral diarrhea admitted to the hospital and 17 clinically normal control puppies. PROCEDURES: Basal serum cortisol and thyroxine concentrations were measured for each dog with parvoviral diarrhea at admission (prior to treatment) and daily until death, euthanasia, or discharge. RESULTS: Median time between admission and death was 48 hours (ie, on day 3). Median serum cortisol concentration on day 1 (admission) in all dogs with parvoviral diarrhea (248 nmol/L) was significantly higher than in control dogs (77 nmol/L). No significant difference was found in the day 1 median serum cortisol concentration of 11 dogs that died (302 nmol/L) and 46 dogs that survived (238 nmol/L). A significantly higher median serum cortisol concentration was, however, found in nonsurvivor group dogs, compared with survivor group dogs, on days 2 and 3. Median serum thyroxine concentration on day 1 in dogs with parvoviral diarrhea was significantly lower than in control dogs (8.12 nmol/L vs 35 nmol/L, respectively). Median serum thyroxine concentration of nonsurvivor group dogs (4.4 nmol/L) was significantly lower than that of survivor group dogs (9.2 nmol/L) at admission and became even lower on days 2 and 3. CONCLUSIONS AND CLINICAL RELEVANCE: High serum cortisol and low serum thyroxine concentrations at 24 and 48 hours after admission were associated with death in dogs with parvoviral diarrhea.     

Susceptibility to onion-induced hemolysis in dogs with hereditary high erythrocyte reduced glutathione and potassium concentrations.

The hemolytic effect of onion consumption in dogs with hereditary high erythrocyte reduced glutathione and potassium concentrations (designated HK dogs) was compared with that in clinically normal dogs. Twelve hours after oral administration of boiled onions (200 g/dog), hemoglobin concentration decreased to 84.4% of the initial value in HK dogs; it decreased only to 90.5% in clinically normal dogs. At 24 hours, methemoglobin concentration was significantly (P less than 0.05) higher in HK dogs than in clinically normal dogs. The concentration of erythrocyte oxidized glutathione increased about fivefold at 10 hours in HK dogs, whereas it did not change during the experimental period in clinically normal dogs. In addition, at 12 hours, the proportion of erythrocytes containing Heinz bodies increased to 24.4% in HK dogs, but increased only to 1.2% in clinically normal dogs. Thus, results indicated that HK dogs were more susceptible to the oxidant action of onions than were clinically normal dogs.     

Lactate as a diagnostic test for septic peritoneal effusions in dogs and cats

Lactate concentration in peritoneal fluid was evaluated and compared to blood lactate concentration in dogs and cats with septic and nonseptic abdominal effusions. All dogs with septic effusions had a peritoneal fluid lactate concentration >2.5 mmol/L and a peritoneal fluid lactate concentration higher than blood lactate, resulting in a negative blood to fluid lactate difference. In dogs, the diagnostic accuracy of the peritoneal fluid lactate concentration and the blood to fluid lactate difference in differentiating septic peritoneal effusion was 95% and 90%, respectively. Peritoneal fluid lactate concentration and blood to fluid lactate difference were not accurate tests for detecting septic peritoneal effusions in cats.     

Effects of treatment with polysulfated glycosaminoglycan on serum cartilage oligomeric matrix protein and C-reactive protein concentrations, serum matrix metalloproteinase-2 and -9 activities, and lameness in dogs with osteoarthritis

OBJECTIVE: To investigate the effects of polysulfated glycosaminoglycan (PSGAG) treatment on serum cartilage oligomeric matrix protein (COMP) concentration, matrix metal-loproteinase-2 (MMP-2) and -9 (MMP-9) activities, C-reactive protein (CRP) concentration, and lameness scores in dogs with osteoarthritis. ANIMALS: 16 dogs with osteoarthritis and 5 clinically normal dogs. PROCEDURES: Dogs with osteoarthritis had a history of chronic lameness, and osteophytes were observed on radiographic evaluation of the affected joint. Polysulfated glycosaminoglycan was administered IM twice a week for a total of 8 treatments to all dogs with osteoarthritis and to clinically normal control dogs. RESULTS: Lameness scores after PSGAG treatment in osteoarthritic dogs improved in 12 of the 16 dogs. Serum COMP concentrations in osteoarthritic dogs were significantly higher than in control dogs before treatment. Lameness scores in osteoarthritic dogs decreased significantly after treatment, compared with before treatment. Lameness scores of 9 dogs with hind limb lameness improved significantly after treatment; these dogs had corresponding decreases in serum COMP concentrations. After treatment, serum COMP concentrations and lameness scores of 7 dogs with forelimb lameness remained high and were significantly higher than those of dogs with hind limb lameness. Serum MMP-9 activities of dogs with forelimb lameness were significantly higher than in dogs with hind limb lameness after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: IM administration of PSGAG inhibited COMP degradation in dogs with osteoarthritis. Results indicate that decreases in serum COMP concentrations might be related to improvement in lameness after PSGAG treatment.     

Blood lactate levels in 31 female dogs with pyometra

Background

Canine pyometra is a life-threatening disease common in countries where spaying of dogs is not routinely performed. The disease is associated with endotoxemia, sepsis, systemic inflammatory response syndrome (SIRS) and a 3–4% mortality rate. Blood lactate analysis is clinically valuable in predicting prognosis and survival, evaluating tissue perfusion and treatment response in human and veterinary critical care settings. The aims of the present study were to investigate 1) the blood lactate levels of female dogs with pyometra by a hand-held analyser and 2) if these levels are related with the clinical status or other biochemical or hematological disorders.

Methods

In total 31 female dogs with pyometra admitted for surgical ovariohysterectomy and 16 healthy female control dogs were included in the present study. A complete physical examination including SIRS-status determination was performed. Blood samples for lactate concentrations, hematological and biochemical parameters, acid-base and blood gas analysis and other laboratory parameters were collected and subsequently analysed. The diagnosis pyometra was verified with histopathological examination of the uterus and ovaries. Increased hospitalisation length and presence of SIRS were used as indicators of outcome.

Results

In the pyometra group the median blood lactate level was 1,6 mmol l^-1 (range <0.8–2.7 mmol l^-1). In the control group the median lactate level was 1,2 mmol l^-1 (range <0.8–2.1 mmol l^-1). Of the 31 bitches 19 (61%) fulfilled 2 or more criteria for SIRS at inclusion, 10 bitches (32%) fulfilled 3 of the SIRS criteria whereas none accomplished more than 3 criteria. Lactate levels did not differ significantly between the pyometra and control group, or between the SIRS positive and SIRS negative dogs with pyometra. Increased lactate concentration (>2.5 mmol l^-1) was demonstrated in one female dog with pyometra (3%), and was not associated with longer hospitalisation or presence of SIRS. Lactate measurement was not indicative of peritonitis. None of the bitches died during or within two months of the hospital stay. The measurements of temperature, heart rate, respiratory rate, percentage bandforms of neutrophilic granulocytes, α₂-globulins, creatinin, pvCO₂, TCO₂ and base excess showed significant differences between the SIRS positive and the SIRS negative pyometra cases.

Conclusion

Increased blood lactate concentrations were demonstrated in 3% (1/31), and SIRS was present in 61% (19/31) of the female dogs with pyometra. Preoperative lactate levels were not related with presence of SIRS or prolonged hospitalisation. Lactate measurement was not indicative of peritonitis. The value of a single and repeated lactate analysis in more severely affected cases remains to be determined.     

Arterial lactate concentration, hospital survival, sepsis and SIRS in critically ill neonatal foals

REASONS FOR PERFORMING STUDY: Blood lactate concentration has been shown to be a useful clinical indicator in human patients, but has not been formally investigated in critically ill foals. OBJECTIVE: To investigate the association of blood lactate with hospital survival, markers of cardiovascular status, metabolic acid base status, sepsis and systemic inflammatory response syndrome (SIRS). METHODS: A database containing clinical, haematological, plasma biochemical and hospital outcome data on neonatal foals referred to an intensive care unit in 2000-2001 was analysed. Seventy-two foals for which arterial lactate was measured at admission were included in the study. RESULTS: Sixty-one foals had an admission lactate concentration > 2.5 mmol/l. Admission lactate was statistically associated with hospital survival, mean arterial pressure, blood creatinine concentration, bacteraemia, anion gap, lactate concentration at 18-36 h after admission and evidence of SIRS, but not with packed cell volume or heart rate. Lactate at 18-36 h was also associated with survival and evidence of SIRS. Anion gap, base excess, base excess due to unidentified anions (BEua), simplified strong ion gap or bicarbonate correctly classified foals for presence of hyperlactaemia (> 5 mmol/l) in < or = 80% of animals. CONCLUSIONS: Admission blood lactate gives important prognostic information. Lactate should be measured rather than assumed from the anion gap, base excess, BEua, simplified strong ion gap or bicarbonate. POTENTIAL RELEVANCE: Blood lactate concentrations at admission are clinically relevant in neonatal foals and warrant further investigation. This should include the clinical value of measuring changes in lactate in response to treatment.     

Nitric Oxide Response in Critically III Dogs

Alterations in nitric oxide (NO)production may play a role in critical illness. Total serum nitrate/nitrite concentrations [SNN (uM/L)], the stable metabolites of NO, have been used as an indirect measure of NO in people, with increased concentrations reported in cases of critical illness. The relationship of nitric oxide (NO) to criticalillness in dgos is unknown. We tested the hypothesis that critically ill intensive care unit (ICU) canine illness in dogs is unknown. We tested the hypothesis that critically ill intesive care unit (ICU) canine patients would have increased SNN as compared to healthy dogs and non-critically ill dogs. An organ failure index score (OFI) was assigned to dogs admitted to the ICU to evaluate trends between disease severtiy and SNN. Critically ill dogs had significantly (p < 0.05) higher SNN (median 10.53) as compared to non-critically ill dogs (median 2.3) and healthy dogs (median 1.92). Critically ill dogs with the most severe disease (as based on OFI) had higher SNN concentrations. Survival of critically ill dogs with SNN of > 15 upon ICU admission (12% survival) was significantly less than survival of critically ill dogs with SNN ≤ 15 (91%) survival).l (Vet. Emerg. & Crit. Care, 9: 195–202, 1999)     

Exacerbation of Hyperlactatemia by Infusion of Lactated Ringer''s Solution in Dogs With Lymphoma

Blood lactate concentrations and acid-base status of six dogs with lymphoma were compared statistically with those from six healthy control dogs before, during, and after a 6-hour infusion of lactated Ringer's solution (LRS). Blood lactate concentrations in dogs with lymphoma were significantly (P less than 0.05) higher immediately before, and at the 1-, 2-, 4-, and 6-hour time periods after infusion when compared with controls. Blood lactate concentrations increased significantly (P = 0.016) after the first hour of infusion in dogs with lymphoma but did not increase in the control dogs. The increase in blood lactate concentrations over baseline values after 1 hour of LRS infusion was significantly (P = 0.008) greater in dogs with lymphoma when compared with controls. Blood lactate concentrations returned to baseline levels after 2 hours of infusion in dogs with lymphoma, suggesting that dogs with lymphoma have a transient inability to handle increased lactate loads when compared with controls. However, the potential to augment lactate use, clearance, or both is present and does occur over time. Blood gas values were not significantly altered within the lymphoma or control dog groups after 6 hours of LRS infusion. Blood bicarbonate concentrations in dogs with lymphoma were significantly decreased before and after LRS infusion when compared with controls.     

Serum total thyroxine, total triiodothyronine, free thyroxine, and thyrotropin concentrations in dogs with nonthyroidal disease

OBJECTIVE: To determine whether nonthyroidal disease of various causes and severity is associated with abnormalities in baseline serum concentrations of total thyroxine (T4), triiodothyronine (T3), free T4, or thyrotropin (thyroid-stimulating hormone [TSH]) in dogs believed to be euthyroid. DESIGN: Case-control study. ANIMALS: 223 dogs with confirmed nonthyroidal diseases and presumptive normal thyroid function, and 150 clinically normal dogs. PROCEDURE: Serum total T4, total T3, free T4, and TSH concentrations were measured in dogs with confirmed nonthyroidal disease. Reference ranges for hormone concentrations were established on the basis of results from 150 clinically normal dogs. RESULTS: In dogs with nonthyroidal disease, median serum concentrations of total T4, total T3, and free T4 were significantly lower than those in clinically normal dogs. Median serum TSH concentration in sick dogs was significantly greater than that of clinically normal dogs. When stratified by severity of disease (ie, mild, moderate, and severe), dogs with severe disease had low serum concentrations of total T4, total T3, or free T4 more commonly than did dogs with mild disease. In contrast, serum TSH concentrations were more likely to remain within the reference range regardless of severity of disease. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that serum total T4, free T4, and total T3 concentrations may be low (ie, in the hypothyroid range) in dogs with moderate to severe nonthyroidal disease. Serum TSH concentrations are more likely to remain within the reference range in sick dogs.     

Evaluation of a hand-held lactate analyzer in dogs

A hand-held lactate test device and a blood gas auto analyzer were compared. The objective of the study was to evaluate the performance of the hand-held device in dogs in a clinical setting. Blood lactate levels were evaluated on 30 samples from healthy client-owned dogs and 48 samples from client-owned dogs with various diseases. A blood sample was collected from each healthy dog by either jugular or cephalic venipuncture and from each sick dog from the jugular, cephalic, or saphenous vein, or from an arterial catheter if applicable. One and a half milliliters of the blood sample was immediately transferred to a heparinized vacutainer tube. Enough blood was then drawn from the heparinized tube to allow split sample simultaneous analysis with both machines. Samples from the sick dogs represented a wide range of clinically relevant lactate values. Good agreement between lactate values from both devices was obtained in both sick and healthy dogs. Lactate values in the healthy group (< 2.9 mmol/L with the hand-held device, < 2.6 mmol/L with the blood gas analyzer) were similar to those previously reported (< 2.5 mmol/L). The results of this study support the use of the hand-held device in dogs in a clinical setting.     

Evaluation of matrix metalloproteinase concentrations in precorneal tear film from dogs with Pseudomonas aeruginosa-associated keratitis

OBJECTIVE: To evaluate the changes in concentrations of matrix metalloproteinase (MMP)-2 and MMP-9 in the precorneal tear film of dogs with Pseudomonas aeruginosa-associated keratitis during corneal healing and stromal remodeling. ANIMALS: 10 dogs with unilateral P aeruginosa-associated keratitis and 10 clinically normal dogs. PROCEDURES: Precorneal tear film samples were collected from both eyes of 10 dogs with unilateral P aeruginosa-associated keratitis on the day of admission to the hospital and then at various time points until complete healing of the cornea was achieved. Precorneal tear film samples were also collected from both eyes of 10 clinically normal adult dogs (control group). Concentrations of MMP-2 and MMP-9 in precorneal tear film samples from each group were determined via gelatin zymography for comparison. RESULTS: The proteolytic processes in the ulcerated eyes decreased as corneal healing progressed. On the day of admission, concentrations of latent and active forms of MMP-2 and MMP-9 in ulcerated eyes were significantly higher than values in the contralateral unaffected eyes in dogs with P aeruginosa-associated keratitis; concentrations of latent MMP-2 and MMP-9 were also greater than control group values. Concentrations of latent and active forms of MMP-2 and MMP-9 in the healed eyes of dogs with P aeruginosa-associated keratitis were significantly lower than concentrations in the ulcerated eyes on the day of admission. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that reduction of precorneal tear film concentrations of MMPs by use of proteinase inhibitors may be effective in the treatment of dogs with P aeruginosa-associated keratitis.