Acid-Base Disturbances: An Emergency Department Approach

Point and Pearls Excerpt

• The bicarbonate buffer system is the predominant buffer system maintained via actions of the kidneys and lungs: CO₂ + H₂O = H₂CO₃ = HCO₃^- + H^₊
• Ventilatory compensation begins within minutes, but takes up to 24 hours for maximal effect; the renal response occurs over hours to days.
• Lactate accumulates due to tissue hypoxia and aerobic glycolysis. Type A lactic acidosis refers to that characterized by poor perfusion and acute hypoxia; type B lactic acidosis occurs in the absence of overt hypoperfusion or hypoxia.
• Mortality associated with hyperlactatemia occurs more often when buffer systems can no longer compensate and a lactic acidosis ensues.

Most Important References

• Kitabchi AE, Umpierrez GE, Miles JM, et al. Hyperglycemic crises in adult patients with diabetes. Diabetes Care. 2009;32(7):1335-1343. (Clinical practice guideline) 
• Lee S-W, Hong Y-S, Park D-W, et al. Lactic acidosis not hyperlactatemia as a predictor of inhospital mortality in septic emergency patients. Emerg Med J. 2008;25(10):659-665. (Prospective observational; 126 patients) 
• Schwartz WB, Relman AS. A critique of the parameters used in the evaluation of acid-base disorders. Whole-blood buffer base and standard bicarbonate compared with blood pH and plasma bicarbonate concentration. N Engl J Med. 1963;268:1382-1388. (Landmark review) 
• Miller M, Eriksson L, Fleisher L, et al. Perioperative Acid- Base Balance. In: Miller’s Anesthesia, 8th Ed. Philadelphia, PA: Elsevier Saunders. 2015; pages 1811-1829. (Textbook chapter)
• Emmett M, Narins RG. Clinical use of the anion gap. Medicine (Baltimore). 1977;56(1):38-54. (Landmark review)
• Astrup P, Jorgensen K, Andersen OS, et al. The acid-base metabolism. A new approach. Lancet. 1960;1(7133):1035-1039. (Landmark review and original contribution) 
• Stewart PA. Independent and dependent variables of acid-base control. Respir Physiol. 1978;33(1):9-26. (Landmark review and original contribution)