Blood Gases Level 1 Tutorial: Blood Gases
Please wait.. Please wait...
Tutorial: Blood Gases
Learn an organized approach to arterial blood gas analysis, incorporating serum and urine electrolyte values into your more advanced levels of analysis.
How to level up?
Develop your skills by completing our Practice Cases!
Tutorial: Blood Gases Metabolic or Respiratory
Times Practiced
Cases Completed
1h 24m
Total Time spent
1m 24s
Average Time
Metabolic or Respiratory
Please see lesson #1 (Acidosis or Alkalosis) for the podcast on this lesson.

After you determine if the pH is acidosis or alkalosis, your next job is to determine what is driving the disturbance. In other words, is it a respiratory process driven by an abnormal CO2 or is it a metabolic process, driven by an abnormal bicarb?

Step 1 is to determine the state of acidosis vs. alkalosis.
Step 2 is to determine what is driving the process.

If acidosis is present, then:
  • high pCO2 could be causing it  ... or ...
  • low bicarb could be causing it

If alkalosis is present, then:
  • a low pCO2 could be causing it ... or ...
  • a high bicarb could be causing it

In a simple world (and it never is), only one process would occur at one time. Most of the time, there is another process also occuring that tries to reverse or balance out the process. This occurs because the body does not like to be acidotic or alkalotic. It likes to be neutral.

When the human body is trying to reverse the primary acid-base problem, we refer to this secondary process as a compensatory process, which we will discuss in the next lesson.

Sometimes, there are processes that are driving the acid-base balance in the same direction. For example, it is possible to have both a respiratory acidosis and a metabolic acidosis at the same time. Or it is possible to have a respiratory alkalosis and metabolic alkalosis both at the same time. These are not compensatory because they do not reverse the problem; they amplify it.