Arterial blood gas analysis was part of everyday intensive care practice for much of the second half of the last century, yet in 2001 considerable differences of opinion and entrenched viewpoints still characterize the evaluation of acid-base disturbances. There are of course relatively non-controversial areas. All agree that in healthy people living near sea-level, the arterial pH will be close to 7.4, and the arterial pCO2 (paCO2) will be close to 40 mmHg. Most define acidemia as arterial pH < 7.35, and alkalemia as pH > 7.45, and agree that in isolated respiratory acidosis, paCO2 exceeds 45 mmHg, and in isolated respiratory alkalosis, paCO2 is less than 35 mmHg. It is also widely understood that metabolic (non-respiratory) acid-base abnormalities are those which manifest on blood gas analysis as a disturbed pH / paCO2 relationship (Fig. 1).


Base Excess Metabolic Alkalosis Base Deficit Buffer Base Unmeasured Anion 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Schlichtig R, Grogono AW, Severinghaus JW (1998) Current status of acid-base quantitation in physiology and medicine. Anesthesiol Clin North Am 16: 211–233.CrossRefGoogle Scholar
  2. 2.
    Schwartz WB, Relman AS (1963) A critique of the parameters used in the evaluation of acid-base disorders. N Engl J Med 268: 1382–1388PubMedCrossRefGoogle Scholar
  3. 3.
    Narins RB, Emmett M (1980) Simple and mixed acid-base disorders: a practical approach. Medicine (Baltimore) 59: 161–187Google Scholar
  4. 4.
    Severinghaus JW (1993) Siggaard-Andersen and the “Great Trans-Atlantic Acid-Base Debate”. Scand J Clin Lab Invest 53 [Suppl] 214: 99–104CrossRefGoogle Scholar
  5. 5.
    Stewart PA (1983) Modern quantitative acid-base chemistry. Can J Physiol Pharmacol 61: 1444–1461PubMedCrossRefGoogle Scholar
  6. 6.
    Siggaard-Andersen O, Fogh-Andersen N (1995) Base excess or buffer base (strong ion difference) as measure of a non-respiratory acid-base disturbance. Acta Anesthesiol Scand 39[Suppl]: 107, 123-128Google Scholar
  7. 7.
    Rossing TH, Maffeo N, Fencl V (1986) Acid-base effects of altering plasma protein concentration in human blood in vitro. J Appl Physiol: 2260–2265Google Scholar
  8. 8.
    Singer RB, Hastings AB (1948) An improved clinical method for the estimation of disturbances of the acid-base balance of human blood. Medicine (Baltimore) 27: 223–242CrossRefGoogle Scholar
  9. 9.
    Figge J, Mydosh T, Fencl V (1992) Serum proteins and acid-base equilibria: a follow-up. J Lab Clin Med 120: 713–719PubMedGoogle Scholar
  10. 10.
    Severinghaus JW (1986) AHA! In: Astrup P, Severinghaus JW (eds.) The history of blood gases, acids and bases. Munksgaard, Copenhagen, pp 264–276Google Scholar
  11. 11.
    Jorgensen K, Astrup P (1957) Standard bicarbonate, its clinical significance, and a new method for its determination. Scand J Clin Lab Invest 9: 122PubMedCrossRefGoogle Scholar
  12. 12.
    Siggaard-Andersen O, Fogh-Andersen N (1995) Base excess or buffer base (strong ion diffe-rence) as measure of a non-respiratory acid-base disturbance. Acta Anesthiesol Scand 39[Suppl]: 107, 123-128Google Scholar
  13. 13.
    Siggaard-Andersen O, Engel K (1960) A micro method for determination of pH, carbon dioxide tension, base excess and standard bicarbonate in capillary blood. Scand J Clin Lab Invest 12: 172–176CrossRefGoogle Scholar
  14. 14.
    Astrup P, Jorgensen K, Siggaard-Andersen O, et al (1960) Acid-base metabolism: new approach. Lancet 1: 1035–1039PubMedCrossRefGoogle Scholar
  15. 15.
    Siggaard-Andersen O (1977) The Van Slyke equation. Scand J Clin Lab Invest 37[Suppl 146]: 15–20CrossRefGoogle Scholar
  16. 16.
    Morgan TJ, Clark C, Endre ZH (2000) The accuracy of base excess — an in vitro evaluation of the Van Slyke equation. Crit Care Med 28: 2932–2936.PubMedCrossRefGoogle Scholar
  17. 17.
    Schlichtig R, Grogono AW, Severinghaus JW (1988) Human PaCO2 and standard base excess compensation for acid-base imbalance. Crit Care Med 26: 1173–1179CrossRefGoogle Scholar
  18. 18.
    Scheingraber S, Rehm M, Sehmisch C, et al (1999) Rapid saline infusion produces hyperchloremic acidosis in patients undergoing gynecologic surgery. Anesthesiology 90: 1265–1270PubMedCrossRefGoogle Scholar
  19. 19.
    McFarlane C, Lee A (1994) A comparison of Plasmalyte 148 and 0.9% saline for intra-operative fluid replacement. Anaesthesia 49: 779–781PubMedCrossRefGoogle Scholar
  20. 20.
    Prough DS, Bidani A (1999) Hyperchloremic metabolic acidosis is a predictable consequence of intraoperative infusion of 0.9% saline. Anesthesiology 90: 1247–1249PubMedCrossRefGoogle Scholar
  21. 21.
    Worthley LIG 1997 Acid-base balance and disorders In Oh TE ed. Intensive care manual. Butterworth-Heinemann Oxford pp 689–699Google Scholar
  22. 22.
    Iberti TJ, Leibowitz AB, Papadakos PJ, et al (1991) Low sensitivity of the anion gap as a screen to detect hyperlactemia in critically ill patients. Crit Care Med 19: 130–131CrossRefGoogle Scholar
  23. 23.
    Salem MM, Mujais SK (1992) Gaps in the anion gap. Arch Intern Med 152: 1625–1629PubMedCrossRefGoogle Scholar
  24. 24.
    Fencl V, Jabor A, Kazda A, et al (2000) Diagnosis of metabolic acid-base disturbances in critically ill patients. Am J Respir Crit Care Med 162: 2246–2251PubMedGoogle Scholar
  25. 25.
    Kellum JA, Kramer DJ, Pinsky MR (1995) Strong ion gap: a methodology for exploring unexplained anions. J Crit Care 10: 51–55PubMedCrossRefGoogle Scholar
  26. 26.
    Gilfix BM, Bique M, Magder S (1993) A physical chemical approach to the analysis of acid-base balance in the clinical setting. J Crit Care 8: 187–197PubMedCrossRefGoogle Scholar
  27. 27.
    Balasubramanyan N, Havens PL, Hoffman GM (1999) Unmeasured anions identified by the Fencl-Stewart method predict mortality better than base excess, anion gap, and lactate in patients in the pediatric intensive care unit. Crit Care Med 27: 1577–1581PubMedCrossRefGoogle Scholar
  28. 28.
    Davis JW, Shackford SR, Holbrook TL (1991) Base deficit as a sensitive indicator of compensated shock and tissue oxygen utilization. Surg Gynecol Obstet 173: 473–476PubMedGoogle Scholar
  29. 29.
    Davis JW (1994) The relationship of base deficit to lactate in porcine hemorrhagic shock and resuscitation. J Trauma 36: 168–172PubMedCrossRefGoogle Scholar
  30. 30.
    Dunham CM, Siegel JH, Weireter L, et al (1991) Oxygen debt and metabolic acidemia as quantitative predictors of mortality and the severity of the ischemic insult in hemorrhagic shock. Crit Care Med 19: 231–243PubMedCrossRefGoogle Scholar
  31. 31.
    Davis JW, Shackford SR, Mackersie RC, et al (1988) Base deficit as a guide to volume resuscitation. J Trauma 28: 1464–1467PubMedCrossRefGoogle Scholar
  32. 32.
    Davis JW, Mackersie RC, Holbrook TL, et al (1991) Base deficit as an indicator of significant abdominal injury. Ann Emerg Med 20: 842–844PubMedCrossRefGoogle Scholar
  33. 33.
    Kaups KL, Davis JW, Dominic WJ (1998) Base deficit as an indicator of resuscitation needs in patients with burn injuries. J Burn Care Rehabil 19: 346–348PubMedCrossRefGoogle Scholar
  34. 34.
    Siegel JH, Rivkind AI, Dalai S, et al (1990) Early physiologic predictors of injury severity and death in blunt multiple trauma. Arch Surg 125: 498–508PubMedCrossRefGoogle Scholar
  35. 35.
    Smith I, Kumar P, Molloy S, et al (2001) Base excess and lactate as prognostic indicators for patients admitted to intensive care. Intensive Care Med 27: 74–83PubMedCrossRefGoogle Scholar
  36. 36.
    Davis JW, Kaups KL, Parks SN (1998) Base deficit is superior to pH in evaluating clearance of acidosis after traumatic shock. J Trauma 44: 114–118PubMedCrossRefGoogle Scholar
  37. 37.
    Davis JW, Parks SN, Kaups KL, et al (1996) Admission base deficit predicts transfusion requirements and risk of complications. J Trauma 41: 769–774PubMedCrossRefGoogle Scholar
  38. 38.
    Davis JW, Kaups KL (1998) Base deficit in the elderly: a marker of severe injury and death. J Trauma 45: 873–877PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Italia 2002

Authors and Affiliations

  • T. J. Morgan
    • 1
  1. 1.Intensive Care FacilityRoyal Brisbane HospitalBrisbaneAustralia

Personalised recommendations