Sodium bicarbonate

Background

• 8.4% solution contains 1mmol of HCO₃^-/mL
• ABC approach to underlying cause ↓pH/toxidrome
• mmol of HCO₃^- to correct a NAGMA = 0.3 x weight x -BE

Indications

• Hyperkalaemia
• Toxidromes with Na⁺ channel blockers (e.g. TCADs)
• Salicylate poisoning (to ↑urinary pH)
• NAGMA due to bicarb loss (e.g. RTA) i.e. normal anion gap = hyperchloraemia metab. acidosis

Side effects

• ↑Na⁺ (1mmol of Na⁺ per 1mmol of HCO₃^-)
• Volume overload
• ↓K⁺, ↓Ca⁺⁺
• Worse CSF & intracellular acidosis (↑ CO₂)
• ↑lactate (cellular hypoxia)
• Tissue necrosis if extravasation

Preparation

• Unless in emergency, dilute prior to admin.

To dilute to 1.26% w/v

• Remove 75mL from a 500mL bag of 5% dextrose
• Add 75mL of 8.4% Na⁺ bicarb. to the remaining 425mL
• Mix well
• Regularly check VBG (pH & lactate), U&E (↓K⁺, ↑Na⁺) and Ca⁺⁺