Chapter 22, Problem 30RQ

One of the debates in fluid therapy for diabetic ketoacidosis (DKA) is whether to administer bicarbonate (bicarb). Although it is generally accepted that bicarb should be given if the patient’s blood pH is <7.1 (life-threatening), most authorities do not give bicarb otherwise. One reason for not administering bicarb relates to the oxygen-binding capacity of hemoglobin. In DKA, patients have low levels of 2,3-BPG [p. 573]. When acidosis is corrected rapidly, 2,3-BPG is much slower to recover and may take 24 or more hours to return to normal.

Draw and label a graph of the normal oxygen-dissociation curve [p. 573]. Briefly explain and draw lines on the same graph to show:

1. (a) what happens to oxygen release during DKA as a result of acidosis and low 2,3-BPG levels.
2. (b) what happens to oxygen release when the metabolic acidosis is rapidly corrected with bicarbonate.