Sodium Bicarbonate: Types, Uses, Routes, by Nurses note

 Sodium Bicarbonate 

Types of Sodium Bicarbonate

• Isotonic sodium bicarbonate 1.26%
• Hypertonic sodium bicarbonate 8.4%

Main Uses

• Correction of metabolic acidosis. 
• Alkalinisation of urine,  e.g.  for salicylate overdose, treatment of rhabdomyolysis. 
• Alkalinisation of blood, e.g. for treatment of tricyclic antidepressant overdose. 

Routes of Administration

• IV. 

Nurses Notes

• Isotonic (1.26%) sodium bicarbonate may be used to correct acidosis associated with renal failure or to induce a forced alkaline diuresis. 
• The hypertonic (8.4%) solution (1mEq HCO3/mL) is rarely required in intensive care practice to raise blood pH in severe metabolic acidosis. 
• Bicarbonate therapy is inappropriate when tissue hypoperfusion or necrosis is present. 
• Administration may be indicated as either specific therapy (e.g.  alkaline diuresis for salicylate overdose ) or if the patient is dyspnoeic in the absence of tissue hypoperfusion (e.g.  Renal Failure)
• Bicarbonate cannot cross the cell membrane without dissociation so the increase in PaCO2 may result in intracellular acidosis and depression of myocardial cell function. 
• A decrease in plasma ionised calcium as a result of alkalinisation may also cause a decrease in myocardial contractility. Significantly worse hemodynamic effects have been reported with bicarbonate compared to equimolar saline in patients with severe heart failure. 
• Convincing human data that bicarbonate improves myocardial contractility or increases responsiveness to circulating catecholamines in severe acidosis are lacking. Acidosis secondary to myocardial depression is related to intracellular changes that are not accurately reflected bt arterial blood chemistry. 
• Excessive administration may cause hyperosmolality, hypernatraemia, hypokalaemia, and sodium overload.
• Bicarbonate may decrease tissue oxygen availability by a left shift of the oxyhaemoglobin dissociation curve.
• Sodium bicarbonate does have a place in the management of acid retention or alkali loss, e.g. chronic renal failure, renal tubular acidosis, fistuae, diarrhoea. Fluid and potassium deficit should be corrected first.