Lactic acidosis occurs commonly and can be a marker of significant physiologic derangements. However what an elevated
lactate level and acidemia connotes and what should be done about it is subject to inconsistent interpretations. This review examines the varied etiologies of
lactic acidosis, the physiologic consequences, and the known effects of its treatment with
sodium bicarbonate.
Lactic acidosis is often assumed to be a marker of hypoperfusion, but it can also result from medications, organ dysfunction, and
sepsis even in the absence of malperfusion. Acidemia causes deleterious effects in almost every organ system, but it can also have positive effects, increasing localized blood flow and
oxygen delivery, as well as providing protection against hypoxic cellular injury. The use of
sodium bicarbonate to correct severe acidemia may be tempting to clinicians, but previous studies have failed to show improved patient outcomes following
bicarbonate administration.
Bicarbonate use is known to decrease vasomotor tone, decrease myocardial contractility, and induce intracellular
acidosis. This suggests that mild to moderate acidemia does not require correction. Most recently, a randomized control trial found a survival benefit in a subgroup of
critically ill patients with serum pH levels <7.2 with concomitant
acute kidney injury. There is no known benefit of correcting serum pH levels ≥ 7.2, and sparse evidence supports
bicarbonate use <7.2. If administered,
bicarbonate is best given as a slow IV infusion in the setting of adequate ventilation and
calcium replacement to mitigate its untoward effects.