Blood Gas Flashcards
A horse presents to you in respiratory distress. You perform blood gas analysis and get the following results: PaCO2- 60 mmHg, PaO2- 75 mmHg, pH 7.255, Base excess= -1.8. How would you describe this horse’s status?
The correct answer is hypoventilation, respiratory acidosis. Hypoventilation is defined by the PaCO2. Normal is about 40 (35-45). This horse has an elevated PaCO2 indicating he is under-ventilating and not blowing off sufficient CO2. This increase in CO2 causes a respiratory acidosis because CO2 is an acid that interacts with carbonic anhydrase to form carbonic acid. This is why the horse’s pH is low (normal pH is about 7.4). The relatively normal base excess indicates there is minimal metabolic component to this horse’s acidosis.
