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.     

Evaluation of a portable lactate analyzer (Lactate Scout) in dogs

BACKGROUND: Measurement of blood lactate concentration has become a common practice in canine medicine. However, the accuracy of portable lactate monitors has not been reported in dogs. OBJECTIVES: The aim of this study was to evaluate the accuracy and precision of a portable analyzer (Lactate-Scout) in measuring canine blood lactate concentration. METHODS: A preliminary study was performed to assess the effects of sample storage time and temperature on plasma lactate concentration. Blood samples obtained from 6 canine patients at our hospital were divided into 8 aliquots and stored at 4 degrees C and 20 degrees C; plasma lactate was measured in duplicate with a spectrophotometric system (Konelab) at 0, 30, 60, 120, and 240 minutes after the blood collection. Values were compared with those obtained immediately after blood collection. Lactate values obtained by the portable method also were compared with those obtained by the reference spectrophotometric analyzer on blood samples collected from 48 additional canine patients. RESULTS: There was no significant effect of storage time (P = .89) or temperature (P = .51) on plasma lactate levels. The correlation between lactate values measured with the Lactate-Scout and the Konelab method was r = .98 (slope = .81, 95% confidence interval = .73-.87; intercept = .20, 95% confidence interval = .13-.31). The level of agreement between the 2 methods was generally good for mean lactate concentrations <5 mmol/L. However, at higher lactate concentrations (5 of 48 samples), the values recorded by the Lactate-Scout analyzer were lower than those measured by the Konelab method. CONCLUSION: The Lactate-Scout analyzer is reliably comparable to a reference method for measuring whole blood lactate concentration in dogs; however, caution should be used when interpreting lactate values of 5 mmol/L and higher.     

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.     

Blood Lactate Concentrations in Anesthetized Dogs with Intracranial Disease

Background: The importance of blood lactate concentrations in dogs with intracranial disease has not been established, despite frequently observed hyperlactatemia in dogs undergoing general anesthesia for advanced imaging, surgery, or both.
Hypothesis: Blood lactate concentrations are elevated in anesthetized dogs with intracranial disease, compared with dogs with intervertebral disc disease (IVDD).
Animals: Eighty-five hospitalized dogs undergoing advanced imaging, surgery, or both for primary neurologic disease; 30 with intracranial disease; 55 with IVDD.
Methods: Retrospective study. Age, breed, neurologic diagnosis, time from anesthesia induction to measurement of blood lactate, blood lactate concentration under anesthesia, and concurrently measured heart rate, mean arterial pressure, PCV, arterial hemoglobin oxygen saturation, and arterial partial pressure of oxygen were included in a multivariable linear regression analysis.
Results: Dogs with meningioma (adjusted mean lactate 2.99 mmol/L, 95% CL 2.21–4.05, P < 0.0001) and hydrocephalus (adjusted mean lactate 1.5 mmol/L, 95% CL 0.99–2.27, P = 0.003) had higher blood lactate concentrations compared with dogs with IVDD (adjusted mean lactate 0.79 mmol/L, 95% CL 0.6–1.04). Only dogs with meningioma had clinically important hyperlactatemia (>2.5 mmol/L).
Conclusions: Prospective studies are warranted to determine the degree and clinical importance of high blood lactate concentrations in dogs with intracranial disease.     

Comparison of canine capillary and jugular venous blood lactate concentrations determined by use of an enzymatic-amperometric bedside system

OBJECTIVE: To evaluate the analytical agreement between blood lactate concentrations determined by use of an enzymatic-amperometric bedside system in capillary blood samples from the pinna and in jugular venous blood samples from dogs. ANIMALS: 53 dogs. PROCEDURES: For each dog, venous and capillary blood samples were obtained from a jugular vein and from the ear pinna (by use of a lancing device), respectively, following a randomized sequence of collection. Lactate concentrations in both types of samples were analyzed by use of an enzymatic-amperometric bedside system intended for lactate detection in capillary blood samples from humans that was previously validated in dogs. The Passing-Bablock regression analysis was used to compare venous and capillary blood lactate concentrations; the level of agreement was calculated by use of the Bland-Altman method. RESULTS: Jugular venous blood samples were collected without difficulty from all 53 dogs. A capillary blood sample was obtained from only 47 dogs. The correlation coefficient between lactate concentrations measured in venous and capillary blood samples was 0.58 (slope, 2.0 [95% confidence interval, 1.5 to 3.0]; intercept, -1.2 [95% confidence interval, -3.1 to 0.4]). The mean difference between methods was 0.72 mmol/L (95% confidence interval, 0.38 to 1.06) with limits of agreement of -1.55 to 2.99 mmol/L. CONCLUSIONS AND CLINICAL RELEVANCE: Because of the lack of agreement between lactate concentrations determined in capillary and jugular venous blood samples, measurement of capillary blood lactate concentration in dogs performed with the technique used in the study does not appear to be a reliable alternative to jugular venous blood measurements.     

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.     

Increased Lactate Concentrations in III and Injured Dogs

Venous blood lactate concentrations were measured on 109 ill dogs and 20 clinically normal dogs. Ill dogs were grouped into survivor and nonsurvivor groups, and categorized based on their primary problem. Ninety-five percent of ill dogs had lactate concentrations higher than clinically normal dogs and published normal values. Seventy-six percent of ill dogs with increased lactate concentrations survived to be discharged. Lactate concentrations were significantly higher in nonsurvivors than in survivors and clinically normal dogs. Lactate concentrations in dogs with major trauma and intoxications, and with cardiopulmonary, gastrointestinal, and neurologic problems were significantly higher than in clinically normal dogs and dogs with other problems. (Vet Emerg & Crit Care, 1998; 8: 117–127)     

Fractionation of canine serum magnesium

BACKGROUND: Serum total magnesium (tMg) consists of 3 fractions: ionized magnesium (iMg), protein-bound magnesium (pbMg), and complexed magnesium (cMg). Serum iMg may be measured by an ion-selective electrode, but determination of pbMg and cMg has not been attempted in dogs. OBJECTIVES: The objectives of this study were to assess the validity of a micropartition system to fractionate serum tMg and to establish reference intervals for pbMg, cMg, and iMg in clinically normal dogs using this method. METHODS: Serum samples from 10 clinically healthy dogs were fractionated using a micropartition system (Centrifree YM-30, Amicon Corp, Lexington, MA, USA). Serum tMg and iMg were measured in whole serum, and tMg was also measured in the ultrafiltrate. Concentration of cMg was obtained by the subtraction of iMg from tMg concentrations of the ultrafiltrate. Protein-bound Mg was calculated by subtracting the tMg concentration of the ultrafiltrate from the tMg concentration of whole serum. RESULTS: Results for pbMg and cMg using the micropartition system showed good reproducibility. Determination of tMg and iMg had acceptable inter- and intra-assay precision. Concentrations of iMg, cMg, and pbMg were 0.50 +/- 0.05 mmol/L, 0.05 +/- 0.04 mmol/L, and 0.24 +/- 0.04 mmol/L, representing 63%, 6%, and 31% of the tMg concentration, respectively. CONCLUSIONS: The micropartition system was a reproducible means to accurately assess cMg and pbMg concentrations in dogs.     

Tei index of myocardial performance applied to the right ventricle in normal dogs

Right ventricular (RV) dysfunction is a cause of exercise intolerance, hypotension, syncope, and heart failure in dogs with cardiac and respiratory disorders. The study objective was to determine Doppler-derived reference values that reflect global RV function in healthy dogs. We measured systolic time intervals and an RV index of myocardial performance (IMP) in 45 healthy dogs between 8 months and 8 years of age. Pulsed-wave Doppler recordings of mitral, tricuspid, aortic, and pulmonic were acquired. Pre-ejection period (PEP), ejection time (ET), PEP/ET, and IMP were determined for both ventricles by separate cardiac cycles. Compared to the mean left ventricular (LV) IMP (0.410; 95% confidence intervals [CI] 0.378-0.442), mean RV IMP (0.250; 95% CI 0.222-0.278) was significantly smaller, and mean ET for the RV (187 millisecond [ms]; 95% CI 182-192) was significantly longer than the LV (173 ms; 95% CI 168-179). A clinically relevant correlation was not found among RV IMP and body weight, heart rate, RV ET, RV PEP, or RV PEP/ET. Calculation of LV IMP with 2 separate sample volumes yielded smaller values than from a single sample volume, with a difference in means of 0.040. We conclude that the RV IMP is relatively independent of body weight and heart rate within the ranges studied and is consistently lower than values derived from the LV in healthy dogs. This study provides additional reference values for RV function in dogs and may be useful for identification of RV dysfunction in dogs.     

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.     

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.     

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.     

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.     

Evaluation of cerebrospinal fluid lactate and plasma lactate concentrations in anesthetized dogs with and without intracranial disease

The objectives of this study were to establish a reference interval for canine cerebrospinal fluid lactate (CSFL) and to compare CSFL and plasma lactate (PL) concentrations in anesthetized dogs with and without intracranial disease. Using a prospective study, canine blood and cerebrospinal fluid were collected for lactate analysis in 11 dogs with intracranial disease after undergoing magnetic resonance imaging (MRI) (Group ID-MRI), in 10 healthy dogs post-MRI (Group H-MRI), and in 39 healthy dogs after induction of anesthesia (Group H-Sx). Dogs were anesthetized for the procedures using different anesthetic protocols. Neurological scores (NS) and sedation scores (SS) were assessed pre-anesthesia in ID-MRI dogs. The CSFL reference interval [90% confidence interval (CI) for lower and upper limits] was 1.1 (1.0 to 1.2) to 2.0 (2.0 to 2.1) mmol/L. Mean ± SD CSFL concentrations were: ID-MRI, 2.1 ± 0.8; H-MRI, 1.6 ± 0.4; and H-Sx, 1.6 ± 0.2 mmol/L. There was a tendency for higher CSFL in dogs in the ID-MRI group than in those in the H-MRI or H-Sx groups (P = 0.12). There was agreement between CSFL and PL in ID-MRI dogs (P = 0.007), but not in dogs in H-MRI (P = 0.5) or H-Sx (P = 0.2). Of the ID-MRI dogs, those with worse NS had higher CSFL (r² = 0.44). The correlation between CSFL and PL in dogs with intracranial disease and between worse NS and higher CSFL warrants further investigation into the use of CSFL and PL for diagnostic and prognostic purposes.     

Effect of sampling site, repeated sampling, pH, and PCO2 on plasma lactate concentration in healthy dogs

OBJECTIVE: To characterize the variation in plasma lactate concentration among samples from commonly used blood sampling sites in conscious, healthy dogs. ANIMALS: 60 healthy dogs. PROCEDURE: Cross-sectional study using a replicated Latin square design. Each dog was assigned to 1 of 6 groups (n = 10) representing all possible orders for 3 sites (cephalic vein, jugular vein, and femoral artery) used to obtain blood. Samples were analyzed immediately, by use of direct amperometry for pH, PO2, Pco2, glucose, and lactate concentration. RESULTS: Significant differences in plasma lactate concentrations were detected among blood samples from the cephalic vein (highest), femoral artery, and jugular vein (lowest). Mean plasma lactate concentration in the first sample obtained, irrespective of sampling site, was lower than in subsequent samples. Covariation was identified among plasma lactate concentration, pH, and PCO2, but correlation coefficients were low. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma lactate concentrations differed among blood samples from various sites. A reference range for plasma lactate concentration was 0.3 to 2.5 mmol/L. Differences in plasma lactate concentrations among samples from various sites and with repeated sampling, in healthy dogs, are small. Use of the reference range may facilitate the clinical use of plasma lactate concentration in dogs.     

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.     

Evaluation of the usefulness of the portable device Lactate Pro for measurement of lactate concentrations in equine whole blood.

Blood lactate measurements are commonly used in exercising horses to determine the onset of lactate accumulation and in colic patients to assess clinical status and to indicate prognosis. To study the usability of a portable blood lactate meter based on dry chemistry (Lactate Pro), the data from this instrument were compared to data from a laboratory-used lactate meter based on wet chemistry (ABL 605 blood gas analyzer [ABL]). Heparinized blood samples were obtained from horses participating in a jumping experiment (n = 9), from horses cantering at maximal speed on a racetrack (n = 7), and from patients admitted to the Department of Equine Sciences at Utrecht University for severe colic (n = 13). Seventeen of these samples were tested in duplicate on both instruments to determine the repeatability of the measurements. Blood lactate concentrations measured with the Lactate Pro ranged from 0.8-17.6 mmol/liter and with the ABL from 1.0-18.6 mmol/liter. The correlation between lactate concentrations obtained using the Lactate Pro and values from the ABL was 0.90, and the relationship was represented by the following formula: y = 0.90 . x + 0.36, indicating a linear relationship between values produced by the ABL and Lactate Pro. The repeatability for the Lactate Pro was high (0.997), which is comparable to the ABL (0.999).     

Breed‐associated variability in serum biochemical analytes in four large‐breed dogs

Background: Genetic background can influence the expected values of hematologic and serum biochemical analytes in domestic animal species. Objective: The purpose of this study was to determine if there are breed‐related differences in serum biochemical variables in healthy purebred dogs of 4 breeds and to develop appropriate reference intervals. Methods: Alaskan Malamutes (n=59), Siberian Huskies (n=78), Golden Retrievers (n=90), and English Setters (n=77) were included in the study. The dogs had a median age of 42 months (range 10–112 months) and each breed included a mix of intact and neutered dogs of both sexes. Serum biochemical profiles (Olympus AU400e) were performed along with physical examinations, CBCs, and urinalyses to ensure dogs were clinically healthy. Differences in the values of biochemical analytes were assessed nonparametrically and reference intervals for all breeds combined were calculated as the central 95% percentile. Results: Significant differences were observed between breeds for all serum biochemical analytes except alkaline phosphatase, glucose, and chloride. The analyte ranges had a large degree of overlap between the different breeds. Conclusions: Although many statistically significant breed‐related differences in serum biochemical values were observed, the differences were small and unlikely to have clinical relevance or impact medical decision making.     

Effect of background serum lithium concentrations on the accuracy of lithium dilution cardiac output determination in dogs

OBJECTIVES: To assess the effect of increasing serum lithium concentrations on lithium dilution cardiac output (LiDCO) determination and to determine the ability to predict the serum lithium concentration from the cumulative lithium chloride dosage. ANIMALS: 10 dogs (7 males, 3 females). PROCEDURE: Cardiac output (CO) was determined in anesthetized dogs by measuring LiDCO and thermodilution cardiac output (TDCO). The effect of the serum lithium concentration on LiDCO was assessed by observing the agreement between TDCO and LiDCO at various serum lithium concentrations. Also, cumulative lithium chloride dosage was compared with the corresponding serum lithium concentrations. RESULTS: 44 paired observations were used. The linear regression analysis for the effect of the serum lithium concentration on the agreement between TDCO and LiDCO revealed a slope of -1.530 (95% confidence interval [CI], -2.388 to -0.671) and a y-intercept of 0.011 (r2 = 0.235). The linear regression analysis for the effect of the cumulative lithium chloride dosage on the serum lithium concentration revealed a slope of 2.291 (95% CI, 2.153 to 2.429) and a y-intercept of 0.008 (r2 = 0.969). CONCLUSIONS AND CLINICAL RELEVANCE: The LiDCO measurement increased slightly as the serum lithium concentration increased. This error was not clinically relevant and was minimal at a serum lithium concentration of 0.1 mmol/L and modest at a concentration of 0.4 mmol/L. The serum lithium concentration can be reliably predicted from the cumulative lithium dosage if lithium chloride is administered often within a short period.     

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.