The Prince William Question

Lets do this number by numbers. This is an algorithm that will allow you to map out any acid-base question.

1. Primary disorder: pH is up (<7.4), pCO12 is down (< 40) and HCO3 is up (>24)The H-H variables are moving in discordant direction so this is an respiratory disorder, the pH is elevated so this is a respiratory alkalosis.

If you are really on the ball you will note that this breaks one of the fundamental guidelines of acid-base in that compensation is not in the same direction as the primary disorder (pCO2 and HCO3 almost always move in the same direction). This only happens when there are two primary disorders.

2. Is there a second primary acid-base disorder affecting compensation?Yes. In Respiratory alkalosis, for every 10 the pCO2 falls the bicarb falls 2 acutely and 4 chronically, so the target HCO3 is 22 for acute respiratory alkalosis and 20 for chronic respiratory alkalosis, well the bicarb did not drop at all, in fact it went up, so there is an additional primary metabolic alkalosis.

3. What is the anion Gap?148-(98+28)=22.So we did not talk about this, but the presence of an anion gap means there is an metabolic acidosis buried deep in the ABG.

4. Calculate the bicarb beforeBicarb before = HCO3 + (Anion gap -12)Bicarb before = 28 (22-12) = 38So without the anion gap the bicarb would be 38, revealing a pretty severe metabolic alkalosis, that is mostly hidden or covered up by the anion gap metabolic acidosis. The severity of the metabolic alkalosis by looking at the electrolytes without the anion gap. 

Put it all together and you have: A respiratory alkalosis, likely from the respiratory stimulant effect of feverA metabolic alkalosis from vomiting and/or some antacids he may have taken to soothe his stomach. An anion gap metabolic acidosis from the sepsis.