HCO₃⁻ Deficit Estimator
Calculate the bicarbonate dose required to raise serum bicarbonate toward a desired target using total body water distribution.
Common targets: 22–24 mEq/L (adjust for chronic conditions).
Adults: 0.4–0.6 (use 0.5). Children: 0.6.
Calculated bicarbonate deficit
420 mEq
How to Use This Calculator
Assess metabolic acidosis
Confirm acidemia, evaluate anion gap, and treat underlying cause before administering bicarbonate.
Enter patient-specific values
Use actual body weight. Target bicarbonate typically 22–24 mEq/L; adjust systemically for chronic disorders.
Replace cautiously
Administer half the calculated deficit initially, recheck blood gases, and avoid overcorrection leading to alkalosis or sodium load.
Formula
Deficit (mEq) = Distribution factor × Weight (kg) × (Target HCO₃⁻ − Current HCO₃⁻)
Distribution factor approximates total body water (Adults ~0.5, Children ~0.6, Elderly ~0.4).
Full Description
Bicarbonate therapy can buffer severe metabolic acidosis when pH is critically low or acidosis is due to bicarbonate loss (e.g., renal tubular acidosis, diarrhoea). The deficit calculation estimates the mEq of bicarbonate needed to raise serum levels toward a target. Because rapid correction risks alkalosis, sodium overload, or paradoxical CNS acidosis, clinicians typically replace only part of the deficit and reassess. Always treat the primary cause of acidosis in parallel.
Frequently Asked Questions
When should bicarbonate be given?
Consider when pH < 7.1 with severe symptoms, or in non-anion-gap metabolic acidosis due to bicarbonate loss. Avoid in lactic acidosis unless guided by specialists.
How much deficit should be corrected initially?
Common practice is to replace half the calculated deficit and reassess. Overcorrection can cause metabolic alkalosis and sodium load.
Does distribution factor vary?
Yes. Use 0.6 for children and lean adults, 0.5 for average adults, and 0.4 for elderly or fluid-overloaded patients to avoid overdosing.
What solution should be used?
Intravenous sodium bicarbonate (typically 8.4% or 4.2%) is used. Oral bicarbonate is an alternative for chronic therapy. Follow institutional protocols.