Emergency Department Care
The initial therapeutic goal for patients with severe acidemia is to raise the systemic pH above 7.1-7.2, a level at which dysrhythmias become less likely and cardiac contractility and responsiveness to catecholamines will be restored.
Metabolic acidosis can be reversed by treating the underlying condition or by replacing the bicarbonate. The decision to give bicarbonate should be based upon the pathophysiology of the specific acidosis, the clinical state of the patient, and the degree of acidosis. [15]
Treating the underlying conditions in high AG states usually is sufficient to reverse the acidosis. Treatment with bicarbonate is unnecessary, except in extreme cases of acidosis when the pH is less than 7.1-7.2. For all cases of diabetic ketoacidosis (DKA), the role of bicarbonate is controversial, regardless of the pH or bicarbonate level.
In hyperchloremic acidosis, the central problem is with the reabsorption or regeneration of bicarbonate. In these conditions, therapy with bicarbonate makes physiologic sense and is prudent in patients with severe acidosis.
Caution with bicarbonate therapy is indicated because of its potential complications, including the following:
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Volume overload
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Hypokalemia
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CNS acidosis
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Hypercapnia
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Tissue hypoxia via leftward shift of hemoglobin-oxygen dissociation curve
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Alkali stimulation of organic acidosis (lactate)
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Overshoot alkalosis
A British study, by Misra et al, indicated that emergency hospital admissions for DKA increased during the coronavirus disease 2019 (COVID-19) pandemic. The investigators looked at the periods from March 1 to June 30, 2020 (first wave of the pandemic); July 1 to Oct 31, 2020 (post–first wave period); and Nov 1, 2020, to Feb 28, 2021 (second wave of the pandemic), comparing them to equivalent periods between March, 2017, and February, 2020. They found that emergency admissions for DKA rose 6%, 6%, and 7%, respectively. However, the changes in emergency DKA admissions varied according to the type of diabetes considered. During the first wave, for example, such admissions in persons with preexisting type 1 diabetes actually fell by 19%, while in those with preexisting type 2 diabetes and patients with newly diagnosed diabetes, the admissions increased by 41% and 57%, respectively. [16]
Consultations
Metabolic acidosis secondary to ingestions (eg, salicylate, methanol, ethylene glycol) often requires dialysis therapy, and a nephrologist should be consulted early in the case management. Toxicologic consultation should also be considered in such cases. Dialysis is the preferred treatment for patients with significant metabolic acidosis in the setting of renal failure.
A retrospective, cross-sectional study by Nogi et al indicated that intermittent hemodialysis can effectively lead to hemodynamic and respiratory stabilization in patients with septic shock complicated by metabolic acidosis. Following the procedure, mean arterial pressure in the study’s patients was found to have increased, minute ventilatory volume to have decreased, norepinephrine requirement to have decreased, bicarbonate level to have increased, and pH to have increased. [17]
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Approach for evaluating metabolic acidosis.
