Lactate has long been used in human clinical practice as a diagnostic and prognostic aid in critically ill patients1. Lactate can be used in sepsis diagnosis and also aid in monitoring post-surgical morbidity, post-cardiac event morbidity, post-transplant morbidity and in assessing patients recovering from pneumonia.
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Normal lactate levels are the same for both dogs and humans. Elevated lactate levels in clinical situations in both man and dogs indicates underlying pathology that requires further investigation.
Increasingly, lactate testing is being used in the veterinary clinic for prognosis and diagnosis in a number of clinical presentations2. Additionally, the availability of hand held lactate analysers and the demonstration that results from hand held lactate analysers have comparable results to laboratory-based lactate testing methods3 means that rapid, cost effective and near patient results are available as a prognostic and diagnostic tool for the veterinarian.
1. Singer et al 2016 JAMA 315 801-810; Shankar-Hari et al 2016 JAMA 315, 775-787; Vincent et al 2016 Critical Care
2. eg Sharkey & Wellman 2015 and Table 1
3. Di Mauro & Schoeffler 2016; Acinero et al 2007; Karagiannis et al 2013
|Lactate is useful tool in treatment decision making|
Whilst lactate is not diagnostic of any particular disease state, when taken in isolation as a single reading, it is a useful tool in overall treatment decision making pathway and as a guide to morbidity and/or the need to monitor more closely specific patients.
For example, a normal lactate value (approx. 2.0 mmol l-1) in dogs is a far better predictor of survival than a high lactate value is of morbidity or death.
Recent studies have highlighted the use of lactate testing for a number of animal conditions.
Troja et al 2018
Gastric dialtion volvulus
Correlation between lactate concentration and dogs with confirmed GDV
Aona et al 2017
Gastric dilatation volvulus
Increased lacate levels assocaited with GDV and changes in ventricular diameter
McQuown et al 2018
Increased lactate in dogs with confirmed lymphoma compared with controls
Robbins et al 2017
Increased lacate correlates with other parameters of fatigue in working dogs
Keyserling et al 2017
Abnormal thoracic radiographs
In dogs with abonormal thoracic xrays not associated with cardio/pulmonary diagnosis, increased lactae was assocaitged with increased morbidity
|Castagnetti et al 2017||Post partum distress||Increased lacacte levels and inability to normalise lacate within 24 of birth was associated increased morbidity in puppies|
|Groppetti et al 2015||Post partum distress||Still born puppies have elevated amniotic fluid lacate levels compared with live births and lacate could be a predictor of post partum outcomes|
|Fahey et al 2017||Cardiac effusion||Elevated lacate levels above 5 mmol L-1 were assocaited with dogs with cardiac effusion|
|Bush et al 2016||Septic peritonitis||Increased lactate levels were associated with secondary septic peritonitis|
|Cortellini et al 2015||Septic peritonitis||Lactate concentration and lactate clearance were good prognostic indicators in dogs with septic peritonitis|
|Gillespie at al 2017||NA||Normal lacate value is a better predictor of survival than a high lacate value is of death|
|Eichenberger et al 2016||Babesiosis||Increased levels of lactate are associated with increased chance of non-survival in confirmed cases of babesia infection|
|Bruchim et al 2016||Heat shock||Lacate is significantly elevated at 12 hours post presenation in non-surviving with heatstroke|
|Sharma & Holowaychuk 2015||Head trauma||Elevated lactae levels post-head trauma is a risk factor for non-survival|
|Proot et al 2015||Septic arthritis||Synovial fluid lactate concentration is significantly increased in septic arthritis and could help rule out this condition in a quick and cost-effective way|
|Ateca et al 2015||Hypotension||Blood lactate is negatively associated with systolic blood pressure and survival probability and may represent a useful prognosis in hypotensive dogs|
|Hall et al 2014||Trauma||Low lacate levels at admsiion were predictive of survival to discharge|
|Malek et al 2013||Post-cholecystectomy recovery||Elevated lacate post gall bladdre removal are assocaited with poor clinical outcomes|
|Volpato et al 2013||Pyometra||Lacate levels are increased in bitches with pyometra|
Cell-Free DNA, High-Mobility Group Box-1, and Procalcitonin Concentrations in Dogs With Gastric Dilatation-Volvulus Syndrome.
Front Vet Sci. 2018 Apr 9;5:67
Evaluation of the association between strong ion acid-base disturbances and mortality in dogs: a retrospective study.
Vet Med Sci. 2018 Apr 10
Clinical use of plasma lactate concentration. Part 2: Prognostic and diagnostic utility and the clinical management of hyperlactatemia.
J Vet Emerg Crit Care (San Antonio). 2018 28(2):106-121
Validation of a portable monitor for assessment of cerebrospinal fluid lactate in dogs.
Vet Clin Pathol. 2018;47(1):108-114
Time-dependent changes and prognostic value of lactatemia during the first 24 h of life in brachycephalic newborn dogs.
Update: Clinical Use of Plasma Lactate.
Vet Clin North Am Small Anim Pract. 2017; 47(2):325-342
Preliminary investigation of blood concentrations of insulin-like growth factor, insulin, lactate and β-hydroxybutyrate in dogs with lymphoma as compared with matched controls.
Vet Comp Oncol.2018 ;16(2):262-267
Prognostic Markers in Acute Babesia canis Infections.
J Vet Intern Med. 2016;30(1):174-182
Prognostic potential of amniotic fluid analysis at birth on canine neonatal outcomes.
Vet J. 2015 ;206(3):423-5
Hospitalized dogs recovery from naturally occurring heatstroke; does serum heat shock protein 72 can provide prognostic biomarker?
Cell Stress Chaperones. 2016;21(1):123-130
Use of Lactate in Small Animal Clinical Practice.
Clin Lab Med. 2015;35(3):567-77
Retrospective evaluation of prognostic indicators in dogs with head trauma: 72 cases (January-March 2011)
J Vet Emerg Crit Care (San Antonio). 2015;25(5):631-639
Analysis of lactate concentrations in canine synovial fluid.
Vet Comp Orthop Traumatol. 2015;28(5):301-5
Survival analysis of critically ill dogs with hypotension with or without hyperlactatemia: 67 cases (2006-2011)
J Am Vet Med Assoc. 2015;1;246(1):100-4
Plasma lactate concentrations in septic peritonitis: A retrospective study of 83 dogs (2007-2012)
J Vet Emerg Crit Care (San Antonio). 2015;25(3):388-395
Multicenter prospective evaluation of dogs with trauma.
J Am Vet Med Assoc. 2014; 244(3):300-8
Clinical findings and prognostic factors for dogs undergoing cholecystectomy for gall bladder mucocele.
Vet Surg. 2013;42(4):418-426
Lactate in bitches with pyometra.
Reprod Domest Anim. 2012;47 Suppl 6:335-336
Comparison of two portable lactate meters in dogs.
J Am Anim Hosp Assoc. 2013;49(1):8-15
Lactate accumulation in muscle cells and blood is a normal consequence of exercise in horses. At low exercise intensity, the aerobic metabolism of glycogen, glucose and fat provides energy in the form of ATP to fuel muscle activity. As exercise intensity increases, oxygen levels can no longer meet the ATP requirement and rather than pyruvate being used in the citric acid cycle in the mitochondria, it is metabolised to lactate to fuel muscle energy requirements. Because lactate cannot be used as an energy source in muscle, lactate is sequestered into the blood for transport to the liver where it is used as an energy source or converted to pyruvate. Blood lactate levels during exercise are therefore an indicator of anaerobic metabolism and provide an indicator of muscle exertion. It is the onset of the “switch” from aerobic to anaerobic metabolism and the ability to maintain steady state lactate levels at any given exercise intensity that is of interest in conditioning athletes, be they human or equine.
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Resting lactate levels in horses are equivalent to those in humans (1.5-2 mmol/L). After exercise horse lactate levels can exceed 20 mmol/L whereas in humans, post exercise levels rarely rise above 10mmol/L
In order to determine optimum training regimes and fitness gains, set exercise tests (SETs) or step tests are used. Typically, a SET consists of a baseline lactate reading (t = 0) and several lactate measurements over 10 – 40 minutes of either steady state exercise (eg treadmill running at a specific velocity) or increasing exercise intensity (eg treadmill running with increased velocity at set time points) followed by a recovery period. The same SET is then performed after a period of training and the plots of the lactate levels are compared. (See figure 1)
Resting blood lactate concentration in the horse is approximately 1–1.5 mmol/L. At low speeds this value does not change greatly from the resting value. At moderate speeds lactate begins to accumulate in the blood with accumulation accelerating when exercise/speed increases above the level at which blood lactate is about 4 mmol/L. This threshold workload at which blood lactate is maintained at 4 mmol/L is often referred to as the anaerobic threshold, or the speed at onset of accumulation of blood lactate (OBLA) and also as VLa4. VLa4 is therefore the work velocity/intensity which results in a blood lactate of approximately 4 mmol/L. This value is derived from inspection of graphs of exercise speed (on the X axis) plotted against blood lactate concentration (on the Y axis) (See figure 1). At speeds greater than VLa4, lactate accumulates rapidly in the blood. The general relationship between velocity and blood lactate is therefore usually described as exponential. However, if sufficient steps are used in the exercise test, the relationship is described by two straight lines, with an obvious velocity at which the blood lactate begins to accumulate in blood.
After a race or intense training, blood lactate concentrations are usually greater than 20 mmol/L. It is normal for the blood and muscle lactate concentration to then gradually decrease over a 1–2 h period after a race or fast work. Acidosis of muscle and blood is a normal result of fast work, and this acidosis is rapidly reversed by the horse’s own metabolism.
Many studies of horses trained on both treadmills and on racetracks consistently demonstrate that training results in lower blood lactate concentrations at the same work speed. The speed at which blood lactate begins to accumulate rapidly, VLa4, also increases ie the horse is able to work at a higher speed/intensity without accumulating lactate. Repeated tests of the blood lactate relationship with velocity are suitable as a means of measuring increasing stamina with training. VLa4 measurements every 2–3 weeks also enable measurement of changes in fitness through the training program.
EKF has described how to take capillary sample in humans, and the same basic principles apply except that lancets should be larger (21G, 7mm) and the fur will need to be shaved at the sample site. As described by Kobayashi (2007), the capillary puncture site should be the central region of the left neck. Shave an area approximately 1cm2 and disinfect with 50% ethanol in water to wash off dirt before exercise. Post exercise, remove sweat using distilled water and puncture the shaved site with a 21G 7mm long lancet. Wipe away the initial drop of blood and use the second drop to take the lactate sample.
|Blood lactate levels provide an indicator of muscle exertion|
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