An ICU patient in septic shock shows the following electrolyte panel results: a serum Na+ of 150 mmol/L, a total CO2 of 18 mmol/L, lactate of 4 mmol/L, and a serum Cl– level of 110 mmol/L

The patient is hypotensive and the RT is unable to obtain an ABG for analysis. What conclu-sion(s) can be drawn regarding this patient's acid-base status?
1. The anion gap is decreased.
2. Metabolic acidosis is present.
3. Anion gap is increased.
4. Lactic acidosis is present.
a. 1, 2, and 4 only
b. 1 only
c. 2 and 4 only
d. 2, 3, and 4 only

ANS: D
The anion gap is calculated by subtracting the sum of CO2 and Cl– from the Na+ (150 – [110 + 18]). In this case the anion gap is elevated (22 mmol/L) and is consistent with a metabolic acido-sis. Normal anion gap is 8-14 mmol/L. The increased lactate values reveal the presence of lactic acidosis due to anaerobic metabolism as a cause of the metabolic acidosis in this patient. Normal lactate range is 0.7 to 2.1 mmol/L.