Urinary alkalinization

Background

• Bicarb raises urinary pH which converts weak acids to their ionized form ("ion trap")

Indications

• Salicylate overdose
  • Recommended for salicylate levels >30 mg/dl
• Phenobarbital overdose (multidose activated charcoal is superior)
• Controversial:
  • Rhabdomyolysis

Contraindications

1. Pt unable to tolerate volume/sodium load
2. Hypokalemia
3. Renal insufficiency

Procedure

1. Give NaHCO3 1-2 mEq/kg IV bolus OR 3-4 mEq/kg IV infusion over 1hr
2. Monitor urinary pH q15-30min until pH is 7.5-8.5
3. Sustain alkalinization by either intermittent bolus or continuous bicarbonate infusion
4. Monitor serum pH (do not allow to rise above 7.5-7.55)
5. Monitor potassium (correct hypokalemia so that alkalinization can continue)

Complications

1. Volume overload
2. pH shifts
3. Hypokalemia