Disorders of the Acid-Base Status
Essentially all pediatric disorders, if severe enough, can lead to acid-base disturbances directly, as a result of therapy, or both.
Acid-base disorders need to be anticipated in all critically ill patients. Proactive monitoring of the acid-base status will allow the early recognition of derangements and the prevention of what could become a life-threatening state.
Acidosis is the most common acid-base derangement in the intensive care unit (ICU), with metabolic acidosis potentially indicating a more severe course and worse outcome.
A pH of <7.2 merely indicates a primary acidosis- inducing disorder. Further assessment of the type of acidosis and the presence of a mixed acid-base disorder requires measurement of pCO2, serum bicarbonate, albumin, and calculation of the anion gap.
The most commonly encountered causes of metabolic acidoses in the ICU are renal insufficiency, sepsis, and DKA, while acute respiratory distress syndrome (ARDS) and severe status asthmaticus are the usual suspects in respiratory acidoses.
Alkalosis, on the other hand, is less common in the ICU. Fluid status derangements and, especially, gastric fluid depletion are the usual underlying causes of metabolic alkaloses, whereas rapid respiration secondary to lung diseases, excessive mechanical ventilation, pain, or central nervous system processes are the common causes of respiratory alkaloses.
In the ICU, identification of acid-base derangements is followed by timely stabilization of the patient irrespective of the underlying cause. Depending on the severity of the derangement and the patient’s response to the stabilizing interventions, the underlying cause might also need to be aggressively sought and emergently reversed.
Identification of the underlying cause(s) of the acid-base disorder at hand may be the final step in the management of these patients, but plays an important role both in the prevention of worsening of the derangement and other complications as well as in the determination of the patient’s overall prognosis.
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- 3.Adrogue HJ, Tobin MJ (1997) Respiratory failure. Blackwell's basics of medicine. Cambridge, MA: Blackwell Science, xii, 560 pGoogle Scholar
- 10.Arieff AI, DeFronzo RA (1985) Fluid, electrolyte, and acid-base disorders. New York: Churchill Livingstone, 2 vols. (xxi 1246, 44 p)Google Scholar
- 11.Bageant R (1975) Variations in arterial blood gas measurements due to sampling techniques. Respiratory Care 20:565Google Scholar
- 17.Cohen JJ, Kassirer JP (1982) Acid-base, 1st ed. Boston: Little, Brown, xxii, 510 pGoogle Scholar
- 19.Cusi K, Consoli A (1994) Alcoholic ketoacidosis and lactic acidosis. Diabetes Rev 2:195–208.Google Scholar
- 38.Hood VL, Tannen RL (1994) Maintenance of acid base homeostasis during ketoacidosis and lactic acidosis: implications for therapy. Diabetes Rev 2:177–94Google Scholar
- 41.Kamel K, Gowrishankar M, Cheema-Dhadli S, et al. (1996) How is acid-base balance maintained in patients with renal tubular acidosis. J Am Soc Nephrol 7:1350Google Scholar
- 43.Kokko J P, Tannen RL (1996) Fluids and electrolytes, 3rd ed. Philadelphia: Saunders, xii, 899 pGoogle Scholar
- 53.Massry SG, Glassock RJ (2001) Massry & Glassock's textbook of nephrology, 4th ed. Philadelphia: Lippincott Williams & Wilkins, xl, 2072 pGoogle Scholar
- 54.Maxwell MH, Kleeman CR, Narins RG (1987) Clinical disorders of fluid and electrolyte metabolism, 4th ed. New York: McGraw-Hill, xiii, 1268 pGoogle Scholar
- 68.Rose BD (2001) Clinical physiology of acid-base and electrolyte disorders, 5th ed. New York: McGraw-Hill, x, 992 pGoogle Scholar
- 69.Schrier RW (2007) Diseases of the kidney and urinary tract, 8th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & WilkinsGoogle Scholar
- 70.Shapiro et al. (1994) Clinical application of blood gases, 5th ed. St. Louis: Mosby-Year Book, p. 128Google Scholar
- 73.Van Yperselle de S, Brasseur L, DeConick JD (1966) The “carbon dioxide response curve” for chronic hypercapnia in man. N Engl J Med 275(3):117–22Google Scholar
- 74.West JB (2005) Respiratory physiology: the essentials, 7th ed. Philadelphia: Lippincott Williams & Wilkins, ix, 186Google Scholar
- 78.Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. The Acute Respiratory Distress Syndrome Network (2000) N Engl J Med 342(18):1301–8Google Scholar