Comparison of anion gap and strong ion gap as predictors of unmeasured strong ion concentration in plasma and serum from horses.
Abstract: To compare the accuracy of anion gap (AG) and strong ion gap (SIG) for predicting unmeasured strong ion concentration in plasma and serum from horses. Methods: 6 well-trained Standardbred horses undergoing high-intensity exercise (experimental study) and 78 horses and ponies that underwent i.v. administration of lactic acid or endotoxin, and endurance, submaximal, or high-intensity exercise. Methods: Anion gap was calculated as AG = (Na+ + K+) - (Cl- + HCO3-), and SIG was calculated, using the simplified strong ion model, whereby SIG (mEq/L) = 2.24 x total protein (g/dl)/(1 + 10(6.65-pH)) - AG. The relation between AG or SIG and plasma lactate concentration was evaluated, using linear regression analysis. Results: Linear relations between plasma lactate concentration and AG and SIG were strong for the experimental study (r2 = 0.960 and 0.966, respectively) and the published studies (r2 = 0.914 and 0.925, respectively). The following relations were derived: AG = 1.00 x plasma lactate + 10.5; SIG = 0.99 x plasma lactate + 2.8. An AG > 15 mEq/L indicated an increased unmeasured anion concentration, whereas a SIG < -2 mEq/L indicated an increased unmeasured strong anion concentration. Conclusions: Anion gap and SIG can be used to predict plasma lactate concentration in horses. AG is accurate and clinically useful for estimating unmeasured strong ion concentration in horses with total protein concentrations within or slightly outside reference range, whereas SIG is more accurate in horses with markedly abnormal total protein concentrations and those of various ages and with various concentrations of albumin, globulin, and phosphate.
Publication Date: 1998-07-11 PubMed ID: 9659556
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- Comparative Study
- Journal Article
Summary
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This study analyzed the use of anion gap (AG) and strong ion gap (SIG) as indicators of unmeasured strong ion concentration in horse plasma and serum, finding both measures can accurately predict plasma lactate concentration, with different measures proving more precise under certain conditions.
Objective and Methods
- The research aimed to compare the accuracy of anion gap (AG) and strong ion gap (SIG) when predicting the unmeasured strong ion concentration in plasma and serum from horses. This is significant as these two measures are often used to assess the extent of metabolic disturbances in equine patients.
- The experiments involved six well-trained standardbred horses involved in intense exercise and 78 horses and ponies given intravenous administration of lactic acid or endotoxin, or subjected to endurance or varied intensity exercise.
- AG is calculated from the concentrations of common ions in blood (sodium, potassium, chloride, bicarbonate), while SIG is calculated using a simplified model that takes into account total protein concentration and pH value.
- The relationship between AG or SIG and plasma lactate concentration, a significant biochemical marker noting tissue oxygen deficit, was evaluated using linear regression analysis.
Results
- The study revealed strong linear relations between plasma lactate concentration and both AG and SIG for the experimental study group and the other varied groups. This suggests that both AG and SIG effectively predict lactate levels.
- It was derived that AG equals the amount of plasma lactate plus 10.5, and SIG equals the amount of plasma lactate plus 2.8.
- An AG greater than 15 mEq/L indicated a higher unmeasured anion concentration and a SIG less than -2 mEq/L pointed to a higher unmeasured strong anion concentration. This provides practical threshold values to use in clinical settings.
Conclusion
- Both measures, AG and SIG, can be used to predict plasma lactate concentration in horses, enabling effective monitoring of metabolic disturbances.
- AG is accurate and clinically useful for estimating unmeasured strong ion concentration in horses with total protein concentrations within or slightly outside the reference range. In contrast, SIG was found more accurate in horses with either markedly abnormal total protein concentrations, or varied concentrations of proteins like albumin, globulin, and phosphate.
Cite This Article
APA
Constable PD, Hinchcliff KW, Muir WW.
(1998).
Comparison of anion gap and strong ion gap as predictors of unmeasured strong ion concentration in plasma and serum from horses.
Am J Vet Res, 59(7), 881-887.
Publication
Researcher Affiliations
- Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana 61801, USA.
MeSH Terms
- Acid-Base Equilibrium
- Animals
- Bicarbonates / blood
- Chlorides / blood
- Electrolytes / blood
- Endotoxins / toxicity
- Horses / blood
- Lactates / blood
- Lactic Acid / pharmacology
- Physical Conditioning, Animal
- Physical Endurance
- Potassium / blood
- Regression Analysis
- Reproducibility of Results
- Sodium / blood
Citations
This article has been cited 13 times.- Bassis S, Fischer S, Köhler H, Reinhold P. Acid-base variables in acute and chronic form of nontuberculous mycobacterial infection in growing goats experimentally inoculated with Mycobacterium avium subsp. hominissuis or Mycobacterium avium subsp. paratuberculosis. PLoS One 2020;15(12):e0243892.
- Gomez DE, Buczinski S, Darby S, Palmisano M, Beatty SSK, Mackay RJ. Agreement of 2 electrolyte analyzers for identifying electrolyte and acid-base disorders in sick horses. J Vet Intern Med 2020 Nov;34(6):2758-2766.
- Zager E, Fletcher DJ, Goggs R. Evaluation of the association between strong ion acid-base disturbances and mortality in dogs: a retrospective study. Vet Med Sci 2018 Apr 10;4(3):206-17.
- Muir W. Effect of Intravenously Administered Crystalloid Solutions on Acid-Base Balance in Domestic Animals. J Vet Intern Med 2017 Sep;31(5):1371-1381.
- Thongprayoon C, Cheungpasitporn W, Cheng Z, Qian Q. Chloride alterations in hospitalized patients: Prevalence and outcome significance. PLoS One 2017;12(3):e0174430.
- Gomez DE, Biermann NM, Sanchez LC. Physicochemical Approach to Determine the Mechanism for Acid-Base Disorders in 793 Hospitalized Foals. J Vet Intern Med 2015 Sep-Oct;29(5):1395-402.
- Trefz FM, Constable PD, Lorenz I. Quantitative physicochemical analysis of acid-base balance and clinical utility of anion gap and strong ion gap in 806 neonatal calves with diarrhea. J Vet Intern Med 2015 Mar-Apr;29(2):678-87.
- Ostermann C, Linde S, Siegling-Vlitakis C, Reinhold P. Evaluation of pulmonary dysfunctions and acid-base imbalances induced by Chlamydia psittaci in a bovine model of respiratory infection. Multidiscip Respir Med 2014;9(1):10.
- Gomez DE, Lofstedt J, Stämpfli HR, Wichtel M, Muirhead T, McClure JT. Contribution of unmeasured anions to acid-base disorders and its association with altered demeanor in 264 calves with neonatal diarrhea. J Vet Intern Med 2013 Nov-Dec;27(6):1604-12.
- Corey HE. Bench-to-bedside review: Fundamental principles of acid-base physiology. Crit Care 2005 Apr;9(2):184-92.
- Wooten EW. Science review: quantitative acid-base physiology using the Stewart model. Crit Care 2004 Dec;8(6):448-52.
- Wilkins PA, Wong D, Slovis NM, Collins N, Barr BS, MacKenzie C, De Solis CN, Castagnetti C, Mariella J, Burns T, Perkins G, Delvescovo B, Sanchez LC, Kemper AM, Magdesian KG, Bedenice D, Taylor SD, Gold J, Dunkel B, Pranzo G, Constable PD. The Systemic Inflammatory Response Syndrome and Predictors of Infection and Mortality in 1068 Critically Ill Newborn Foals. J Vet Intern Med 2025 Mar-Apr;39(2):e70004.
- Titotto AC, Santos MM, Ramos GV, Adão MDS, Benvenuto GV, De Lacerda LCC, Lisbôa JAN, Lacerda-Neto JC. Effect of Lactate Minimum Speed-Guided Training on the Fluid, Electrolyte and Acid-Base Status of Horses. Animals (Basel) 2023 Oct 21;13(20).
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