Electrolyte studies. 2. Potassium, chloride, and acid-base.

Hypokalemia plus elevated carbon dioxide (CO2) content usually indicates renal or gastrointestinal potassium (K+) loss. Hypokalemia plus decreased CO2 content usually means intestinal K+ loss. Hyperkalemia is common in metabolic acidosis and oliguric renal failure. With hemolysis or thrombocytosis, serum K+ concentration may be elevated while plasma concentration is normal. A CO2 value less than 18 mmole/liter suggests metabolic acidosis; a value greater than 30 mmole/liter suggests metabolic alkalosis.