What are the clinical findings of hypochloremia (Chloride level of 113 mEq/L) and metabolic acidosis (CO2 level of 16 mEq/L)?

From the Guidelines

The laboratory findings of a chloride level of 113 mmol/L and a CO2 (bicarbonate) of 16 mmol/L indicate a state of metabolic acidosis, which requires prompt evaluation and management to prevent complications such as increased protein degradation and decreased albumin synthesis 1.

Key Findings

• The patient's bicarbonate level is below the recommended target of 22 mmol/L, which is associated with adverse outcomes in patients with chronic renal failure 1.
• The elevated chloride level and decreased bicarbonate create an increased anion gap, disrupting the body's acid-base balance.
• Immediate management should focus on treating the underlying condition rather than just correcting the electrolyte abnormalities.

Management

• Normalization of the serum bicarbonate concentration can be achieved by oral supplementation with bicarbonate salts, such as sodium bicarbonate, at a dose of 2 to 4 g/d or 25 to 50 mEq/d 1.
• Additional laboratory tests, including potassium, sodium, blood glucose, ketones, and renal function, would be helpful to determine the specific cause and guide targeted treatment.
• If the patient is symptomatic, intravenous fluids with appropriate electrolyte composition may be needed to correct the acid-base disturbance.

Underlying Causes

• The patient should be evaluated for underlying causes of metabolic acidosis, such as renal tubular acidosis, diarrhea, or early diabetic ketoacidosis.
• Correction of acidemia due to metabolic acidosis has been associated with increased serum albumin, decreased protein degradation rates, and increased plasma concentrations of branched chain amino acids 1.

From the Research

Metabolic Acidosis Findings

• Chloride level of 113 and CO2 level of 16 may indicate metabolic acidosis, as characterized by a primary reduction in serum bicarbonate (HCO(3)(-)) concentration and a secondary decrease in the arterial partial pressure of carbon dioxide (PaCO(2)) 2
• The calculation of the serum anion gap, calculated as [Na(+)] - ([HCO(3)(-)] + [Cl(-)]), aids diagnosis by classifying the disorders into categories of normal (hyperchloremic) anion gap or elevated anion gap 2
• Metabolic acidosis can occur as a result of either the accumulation of endogenous acids that consumes bicarbonate (high anion gap metabolic acidosis) or loss of bicarbonate from the gastrointestinal tract or the kidney (hyperchloremic or normal anion gap metabolic acidosis) 3

Treatment and Management

• The appropriate treatment of acute metabolic acidosis, in particular organic form of acidosis such as lactic acidosis, has been very controversial, with some studies suggesting that treatment with sodium bicarbonate failed to reduce the morbidity and mortality despite improvement in acid-base parameters 3
• However, other studies have shown that treatment of metabolic acidosis with sodium bicarbonate can improve kidney and patient survival in patients with chronic kidney disease (CKD) 4
• Dietary alkali treatment of metabolic acidosis in CKD, using base-producing fruits and vegetables or oral bicarbonate, may also preserve glomerular filtration rate (GFR) and reduce urine angiotensinogen 5

Adverse Effects

• Acute metabolic acidosis can have adverse effects such as decreased cardiac output, arterial dilatation with hypotension, altered oxygen delivery, decreased ATP production, predisposition to arrhythmias, and impairment of the immune response 2
• Chronic metabolic acidosis can have adverse effects such as increased muscle degradation and abnormal bone metabolism 2