Q: Please elaborate on why bicarbonate is not used unless the ph is 7.2 or less. Many nurses, particularly cardiovascular nurses, have difficulty understanding this when the patient’s blood pressure is low and the patient is acidotic with large negative base excesses. Please explain the physiological basis for the decision and clarify why “it doesn’t work” or “it is not beneficial.”
A: Myra F. Ellis, RN, MSN, CCRN-CSC, replies:
Bicarbonate therapy is sometimes prescribed to treat acute metabolic acidosis, an acid-base disorder that is characterized by a primary decrease in the concentration of bicarbonate ions (HCO3−), a compensatory decrease in the partial pressure of carbon dioxide (PaCO2), and a decrease in serum pH.1 Acidosis is considered severe when the pH is less than 7.20. Assuming an appropriate ventilatory response, this blood pH would be associated with a serum HCO3− concentration of less...