acid base equilibrium


Summary: The balance between acids and bases in the BODY FLUIDS. The pH (HYDROGEN-ION CONCENTRATION) of the arterial BLOOD provides an index for the total body acid-base balance.

Top Publications

  1. Fenton T, Lyon A, Eliasziw M, Tough S, Hanley D. Phosphate decreases urine calcium and increases calcium balance: a meta-analysis of the osteoporosis acid-ash diet hypothesis. Nutr J. 2009;8:41 pubmed publisher
    ..Dietary advice that dairy products, meats, and grains are detrimental to bone health due to "acidic" phosphate content needs reassessment. There is no evidence that higher phosphate intakes are detrimental to bone health. ..
  2. Katzir Z, Dinour D, Reznik Wolf H, Nissenkorn A, Holtzman E. Familial pure proximal renal tubular acidosis--a clinical and genetic study. Nephrol Dial Transplant. 2008;23:1211-5 pubmed
    ..Objectives. We report a unique family with isolated pRTA. The aim of the project was to define the phenotype and to try to find the gene defect causing the disease...
  3. Chappell D, Hofmann Kiefer K, Jacob M, Conzen P, Rehm M. [Metabolic alkalosis despite hyperlactatemia and hypercapnia. Interpretation and therapy with help of the Stewart concept]. Anaesthesist. 2008;57:139-42 pubmed
    ..The modern Stewart concept provides enhanced information, enabling an exact diagnosis and causal therapy even in complex cases. ..
  4. Bruegger D, Kemming G, Jacob M, Meisner F, Wojtczyk C, Packert K, et al. Causes of metabolic acidosis in canine hemorrhagic shock: role of unmeasured ions. Crit Care. 2007;11:R130 pubmed
    ..Capillary electrophoresis suggested that the hitherto unmeasured anions citrate and acetate, but not sulfate, contributed significantly to the changes in strong ion gap associated with induction of shock. ..
  5. Arnett T. Extracellular pH regulates bone cell function. J Nutr. 2008;138:415S-418S pubmed
    ..Diets or drugs that shift acid-base balance in the alkaline direction may provide useful treatments for bone loss disorders. ..
  6. Frassetto L, Morris R, Sellmeyer D, Sebastian A. Adverse effects of sodium chloride on bone in the aging human population resulting from habitual consumption of typical American diets. J Nutr. 2008;138:419S-422S pubmed
    ..We focus here on the American diet's potential effects on bone through its superphysiologic content of sodium chloride. ..
  7. Venkatesh B, Morgan T. Unmeasured anions: the unknown unknowns. Crit Care. 2008;12:113 pubmed publisher
    ..Both the anion gap and the strong ion gap are used as scanning tools for recognition of these anions. The mechanisms underlying these elevations and their significance require further clarification. ..
  8. Morelli A, Ertmer C, Lange M, Dunser M, Rehberg S, Van Aken H, et al. Effects of short-term simultaneous infusion of dobutamine and terlipressin in patients with septic shock: the DOBUPRESS study. Br J Anaesth. 2008;100:494-503 pubmed publisher
  9. Chawla L, Jagasia D, Abell L, Seneff M, Egan M, Danino N, et al. Anion gap, anion gap corrected for albumin, and base deficit fail to accurately diagnose clinically significant hyperlactatemia in critically ill patients. J Intensive Care Med. 2008;23:122-7 pubmed
    ..Serum lactate should be measured in all critically ill adults in whom hypoperfusion is suspected. ..

More Information


  1. Fenton T, Lyon A, Eliasziw M, Tough S, Hanley D. Meta-analysis of the effect of the acid-ash hypothesis of osteoporosis on calcium balance. J Bone Miner Res. 2009;24:1835-40 pubmed publisher
    ..Changes of urine calcium do not accurately represent calcium balance. Promotion of the "alkaline diet" to prevent calcium loss is not justified. ..
  2. Mardon J, Habauzit V, Trzeciakiewicz A, Davicco M, Lebecque P, Mercier S, et al. Long-term intake of a high-protein diet with or without potassium citrate modulates acid-base metabolism, but not bone status, in male rats. J Nutr. 2008;138:718-24 pubmed
    ..This study suggests that lifelong excess of dietary protein results in low-grade metabolic acidosis without affecting the skeleton, which may be protected by an adequate calcium supply. ..
  3. Kaplan L, Kellum J. Initial pH, base deficit, lactate, anion gap, strong ion difference, and strong ion gap predict outcome from major vascular injury. Crit Care Med. 2004;32:1120-4 pubmed
    ..The strong ion gap is most strongly predictive of mortality following major vascular trauma. ..
  4. Bruegger D, Bauer A, Rehm M, Niklas M, Jacob M, Irlbeck M, et al. Effect of hypertonic saline dextran on acid-base balance in patients undergoing surgery of abdominal aortic aneurysm. Crit Care Med. 2005;33:556-63 pubmed
    ..This suggests dilution of plasma buffers or a decrease in strong ion difference to be the primary cause of metabolic acidosis. ..
  5. Morgan T, Cowley D, Weier S, Venkatesh B. Stability of the strong ion gap versus the anion gap over extremes of PCO2 and pH. Anaesth Intensive Care. 2007;35:370-3 pubmed
    ..01; hypoalbuminaemic blood: 16.5 (0.8) mEq/l versus 11.8 (2.0) mEq/l, P < 0.05). We conclude that, unlike the AG, the SIG is not affected by severe respiratory acidosis and alkalosis, enhancing its utility in acid-base disturbances. ..
  6. Kellum J. Determinants of plasma acid-base balance. Crit Care Clin. 2005;21:329-46 pubmed
    ..All changes in blood pH, in health and in disease, occur through changes in these three variables. This article reviews the physical-chemical approach to acid-base balance and considers clinical implications for these findings. ..
  7. Kellum J. Unknown anions and gaps in medical knowledge. Pediatr Crit Care Med. 2005;6:373-4 pubmed
  8. New S. Intake of fruit and vegetables: implications for bone health. Proc Nutr Soc. 2003;62:889-99 pubmed
  9. Kullmann T, Barta I, Lazar Z, Szili B, Barat E, Valyon M, et al. Exhaled breath condensate pH standardised for CO2 partial pressure. Eur Respir J. 2007;29:496-501 pubmed
    ..Condensate CO2 partial pressure influences pH measurements. Determination of pH at a standard CO2 level provides the most reproducible condensate pH values to date. ..
  10. Moe O, Huang C. Hypercalciuria from acid load: renal mechanisms. J Nephrol. 2006;19 Suppl 9:S53-61 pubmed
    ..At least one component of the acid effect is due to renal leak of calcium. This article summarizes the effect of acid on renal handling of calcium in the proximal tubule, thick ascending limb, and distal convoluted tubule. ..
  11. Ring T, Frische S, Nielsen S. Clinical review: Renal tubular acidosis--a physicochemical approach. Crit Care. 2005;9:573-80 pubmed
    ..Also, recent evidence from physiology that pH may not regulate acid-base transport is in accordance with the concepts presented by Stewart. ..
  12. Forni L, McKinnon W, Lord G, Treacher D, Peron J, Hilton P. Circulating anions usually associated with the Krebs cycle in patients with metabolic acidosis. Crit Care. 2005;9:R591-5 pubmed
    ..These anions are not significantly elevated in patients with normal anion gap acidosis. ..
  13. Boerma E, van der Voort P, Ince C. Sublingual microcirculatory flow is impaired by the vasopressin-analogue terlipressin in a patient with catecholamine-resistant septic shock. Acta Anaesthesiol Scand. 2005;49:1387-90 pubmed
    ..It indicates that much caution should be taken when considering such potent vasoconstrictor when correcting blood pressure during shock...
  14. Constable P, Stämpfli H. Experimental determination of net protein charge and A(tot) and K(a) of nonvolatile buffers in canine plasma. J Vet Intern Med. 2005;19:507-14 pubmed
    ..25 mEq/g of total protein or 0.42 mEq/g of albumin. Application of the experimentally determined values for A(tot), K(a), and net protein charge should improve understanding of the mechanism for complex acid-base disturbances in dogs. ..
  15. Durward A, Tibby S, Skellett S, Austin C, Anderson D, Murdoch I. The strong ion gap predicts mortality in children following cardiopulmonary bypass surgery. Pediatr Crit Care Med. 2005;6:281-5 pubmed
    ..85 [95% confidence interval, 0.74-0.95] vs. 0.71 [95% confidence interval, 0.44-0.98], respectively). An elevated strong ion gap occurs commonly following bypass surgery and appears to be superior to lactate as a mortality predictor. ..
  16. Macdonald H, New S, Fraser W, Campbell M, Reid D. Low dietary potassium intakes and high dietary estimates of net endogenous acid production are associated with low bone mineral density in premenopausal women and increased markers of bone resorption in postmenopausal women. Am J Clin Nutr. 2005;81:923-33 pubmed
    ..Algorithms based on dietary intakes of key nutrients can be used to approximate net endogenous acid production (NEAP) and to explore the association between dietary acidity and bone health...
  17. Murray D, Olhsson V, Fraser J. Defining acidosis in postoperative cardiac patients using Stewart's method of strong ion difference. Pediatr Crit Care Med. 2004;5:240-5 pubmed
    ..Base deficit correlates poorly with true tissue acidosis, and corrected anion gap offers the most accurate bedside alternative to Stewart's method of tissue acid calculation. ..
  18. Corey H. Bench-to-bedside review: Fundamental principles of acid-base physiology. Crit Care. 2005;9:184-92 pubmed
    ..In order to shed light on this controversy, we review the derivation and application of new models of acid-base balance. ..
  19. Osther P, Engel K, Kildeberg P. Renal response to acute acid loading--an organ physiological approach. Scand J Urol Nephrol. 2004;38:62-8 pubmed
  20. Apsner R, Buchmayer H, Gruber D, Sunder Plassmann G. Citrate for long-term hemodialysis: prospective study of 1,009 consecutive high-flux treatments in 59 patients. Am J Kidney Dis. 2005;45:557-64 pubmed
    ..Measured ionized calcium levels should be interpreted with care if central venous catheters are used for vascular access because they could be biased by recirculation. ..
  21. Paroutis P, Touret N, Grinstein S. The pH of the secretory pathway: measurement, determinants, and regulation. Physiology (Bethesda). 2004;19:207-15 pubmed
    ..The methods used for measurement of pH in the secretory pathway, its determinants, and its regulation are the subjects of this review. ..
  22. Evans D, Piermarini P, Choe K. The multifunctional fish gill: dominant site of gas exchange, osmoregulation, acid-base regulation, and excretion of nitrogenous waste. Physiol Rev. 2005;85:97-177 pubmed
    ..Nevertheless, substantial questions about the evolution of these mechanisms and control remain. ..
  23. Wooten E. Science review: quantitative acid-base physiology using the Stewart model. Crit Care. 2004;8:448-52 pubmed
  24. Demigne C, Sabboh H, Remesy C, Meneton P. Protective effects of high dietary potassium: nutritional and metabolic aspects. J Nutr. 2004;134:2903-6 pubmed
    ..The need to ensure a 2.5- to 3.5-g daily K+ supply from fruits and vegetables represents a strong rationale for the "5-10 servings per day" recommendations...
  25. Wall S, Kim Y, Stanley L, Glapion D, Everett L, Green E, et al. NaCl restriction upregulates renal Slc26a4 through subcellular redistribution: role in Cl- conservation. Hypertension. 2004;44:982-7 pubmed
    ..We conclude that Slc26a4 is upregulated with NaCl restriction and is critical in the maintenance of acid-base balance and in the renal conservation of Cl- and water during NaCl restriction. ..
  26. Bruegger D, Jacob M, Scheingraber S, Conzen P, Becker B, Finsterer U, et al. Changes in acid-base balance following bolus infusion of 20% albumin solution in humans. Intensive Care Med. 2005;31:1123-7 pubmed
    ..Alternatively, the acidifying effect of the 20% albumin solution may stem from the titratable acid content of the solution. ..
  27. Morgan T, Venkatesh B, Hall J. Crystalloid strong ion difference determines metabolic acid-base change during acute normovolaemic haemodilution. Intensive Care Med. 2004;30:1432-7 pubmed
    ..The SID of a crystalloid balanced for normovolaemic haemodilution is 24 mEq/l. These principles are applicable in designing fluids for volume resuscitation, acute normovolaemic haemodilution and cardio-pulmonary bypass. ..
  28. Dondorp A, Chau T, Phu N, Mai N, Loc P, Chuong L, et al. Unidentified acids of strong prognostic significance in severe malaria. Crit Care Med. 2004;32:1683-8 pubmed
    ..In severe malaria, unidentified anions other than lactate are the most important contributors to metabolic acidosis, a major cause of death. The strong anion gap is a powerful prognostic indicator in patients with severe malaria. ..
  29. Kellum J, Song M, Li J. Science review: extracellular acidosis and the immune response: clinical and physiologic implications. Crit Care. 2004;8:331-6 pubmed
    ..Finally, we discuss potential clinical implications. ..
  30. Dinh C, Ng R, Grandinetti A, Joffe A, Chow D. Correcting the anion gap for hypoalbuminaemia does not improve detection of hyperlactataemia. Emerg Med J. 2006;23:627-9 pubmed
    ..The cAG provides no additional advantage over the anion gap in the detection of hyperlactataemia. ..
  31. Morgan T. The meaning of acid-base abnormalities in the intensive care unit: part III -- effects of fluid administration. Crit Care. 2005;9:204-11 pubmed
    ..Thus, Stewart's approach not only explains fluid induced acid-base phenomena but also provides a framework for the design of fluids for specific acid-base effects. ..
  32. Constable P, Gelfert C, Furll M, Staufenbiel R, Stämpfli H. Application of strong ion difference theory to urine and the relationship between urine pH and net acid excretion in cattle. Am J Vet Res. 2009;70:915-25 pubmed publisher
    ..Urine pH provided an accurate assessment of NAE in cattle when pH was > 6.3. ..
  33. Oudemans van Straaten H, Fiaccadori E, Baldwin I. Anticoagulation for renal replacement therapy: different methods to improve safety. Contrib Nephrol. 2010;165:251-62 pubmed publisher
    ..If so, the use of citrate may improve patient and kidney survival. Further studies are needed to confirm and explain this benefit. ..
  34. Sumpelmann R, Witt L, Brütt M, Osterkorn D, Koppert W, Osthaus W. Changes in acid-base, electrolyte and hemoglobin concentrations during infusion of hydroxyethyl starch 130/0.42/6 : 1 in normal saline or in balanced electrolyte solution in children. Paediatr Anaesth. 2010;20:100-4 pubmed publisher
    ..01). No serious adverse drug reactions were observed. Infusion related iatrogenic acid-base and electrolyte alterations can be minimized by using hydroxyethyl starch in a balanced electrolyte solution instead of normal saline. ..
  35. Amrein K, Katschnig C, Sipurzynski S, Stojakovic T, Lanzer G, Stach E, et al. Apheresis affects bone and mineral metabolism. Bone. 2010;46:789-95 pubmed publisher
    ..Regular donations of blood components compromised BMD at the lumbar spine. If confirmed, strategies to prevent long-term effects on bone need to be formulated. ..
  36. Aktas D, Cook P. A lysine-tyrosine pair carries out acid-base chemistry in the metal ion-dependent pyridine dinucleotide-linked beta-hydroxyacid oxidative decarboxylases. Biochemistry. 2009;48:3565-77 pubmed publisher
    ..Differences exist in the mechanism for generating the neutral form of lysine so that it can act as a base. ..
  37. Tagliazucchi M, Calvo E, Szleifer I. Redox and acid-base coupling in ultrathin polyelectrolyte films. Langmuir. 2008;24:2869-77 pubmed publisher
    ..For example, the film thickness shows a maximum with electrolyte ionic strength, whose origin is attributed to the balance between electrostatic amino-amino repulsions and amino-sulfonate attractions. ..
  38. Lindinger M, Heigenhauser G. Last word on point:counterpoint: lactate is/is not the only physicochemical contributor to the acidosis of exercise. J Appl Physiol (1985). 2008;105:369 pubmed publisher
  39. González Félix M, Castillo Yañez F, Ocaño Higuera V, Perez Velazquez M, Cota Moreno V, Lozano Taylor J. Effect of dietary protein source and time on alkaline proteolytic activity of Nile tilapia (Oreochromis niloticus). Fish Physiol Biochem. 2010;36:779-785 pubmed publisher
  40. Liamis G, Milionis H, Elisaf M. Pharmacologically-induced metabolic acidosis: a review. Drug Saf. 2010;33:371-91 pubmed publisher
    ..In all cases of drug-related metabolic acidosis, discontinuation of the culprit medications and avoidance of readministration is advised. ..
  41. Kraut J, Madias N. Metabolic acidosis: pathophysiology, diagnosis and management. Nat Rev Nephrol. 2010;6:274-85 pubmed publisher
    ..By contrast, the administration of base for the treatment of chronic metabolic acidosis is associated with improved cellular function and few complications. ..
  42. Cross K, Randell K, Herr S. A 19-month-old boy with recurrent respiratory distress. Pediatr Emerg Care. 2010;26:134-8 pubmed publisher
    ..He was discharged to routine care at home. His parents brought him back the next day for persistent respiratory distress despite routine home albuterol. A check of electrolytes showed a low bicarbonate level. ..
  43. Lacruz R, Nanci A, Kurtz I, Wright J, Paine M. Regulation of pH During Amelogenesis. Calcif Tissue Int. 2010;86:91-103 pubmed publisher
  44. Vormann J, Remer T. Dietary, metabolic, physiologic, and disease-related aspects of acid-base balance: foreword to the contributions of the second International Acid-Base Symposium. J Nutr. 2008;138:413S-414S pubmed
    ..The Second International Acid-Base Symposium, Nutrition-Health-Disease, provided deeper insight and updates in the scientific basis of the relation among diet, acid-base homeostasis, physiology, and pathophysiological consequences. ..
  45. Preisig P. The acid-activated signaling pathway: starting with Pyk2 and ending with increased NHE3 activity. Kidney Int. 2007;72:1324-9 pubmed
  46. Kraut J, Madias N. Serum anion gap: its uses and limitations in clinical medicine. Clin J Am Soc Nephrol. 2007;2:162-74 pubmed
    ..Despite these caveats, calculation of the serum anion gap remains an inexpensive and effective tool that aids detection of various acid-base disorders, hematologic malignancies, and intoxications. ..
  47. Gelfert C, Loeffler L, Fromer S, Engel M, Manner K, Staufenbiel R. Comparison of the impact of different anionic salts on the acid-base status and calcium metabolism in non-lactating, non-pregnant dairy cows. Vet J. 2010;185:305-9 pubmed publisher
    ..The effect of other chloride salts did not differ from calcium sulfate. There was no indication that chloride salts in general have a greater impact than sulfate salts on the ABS. ..
  48. Perry S, Vulesevic B, Grosell M, Bayaa M. Evidence that SLC26 anion transporters mediate branchial chloride uptake in adult zebrafish (Danio rerio). Am J Physiol Regul Integr Comp Physiol. 2009;297:R988-97 pubmed publisher
  49. Kiwull Schöne H, Kiwull P, Manz F, Kalhoff H. Food composition and acid-base balance: alimentary alkali depletion and acid load in herbivores. J Nutr. 2008;138:431S-434S pubmed
    ..We conclude that exhausted renal base-saving function by dietary alkali depletion is a prerequisite for growing susceptibility to NH4Cl-induced chronic metabolic acidosis in the herbivore rabbit. ..
  50. Rastegar A. Use of the DeltaAG/DeltaHCO3- ratio in the diagnosis of mixed acid-base disorders. J Am Soc Nephrol. 2007;18:2429-31 pubmed
    ..The ratio should therefore be used cautiously in making a diagnosis of mixed acid-base disorders. ..
  51. Handy J, Soni N. Physiological effects of hyperchloraemia and acidosis. Br J Anaesth. 2008;101:141-50 pubmed publisher
    ..It is intended to provide an assessment of the importance of hyperchloraemic acidosis and thereby the likely benefits of balanced solutions. ..
  52. Kortmann W, van Agtmael M, van Diessen J, Kanen B, Jakobs C, Nanayakkara P. 5-Oxoproline as a cause of high anion gap metabolic acidosis: an uncommon cause with common risk factors. Neth J Med. 2008;66:354-7 pubmed
    ..We present three cases of high anion gap metabolic acidosis due to 5-oxoproline seen within a period of six months. ..
  53. Shaw A. Bicarbonate and chloride equilibrium and acid-base balance in the neonate. Neonatal Netw. 2008;27:261-6 pubmed