Ventilation to Correct Abnormal ABGs: Key Questions

After initiation of ventilation, ABGs are used to assess the effectiveness of the current settings. When approaching ventilation changes to fix an ABG, a clinician has to ask themselves six separate questions:

1. What issues can I fix with ventilation?
2. Which ventilation setting affects which ABG value?
3. What are the problems with the blood gas, if any?
4. What settings could I change to fix the problem?
5. Which change(s) would be most correct for my patient?
6. How much should I change my settings by?

Questions 1 and 2 will help you when you are starting out, but once you master these concepts, you will no longer need to ask them every time. But Questions 3, 4, 5 and 6 are always asked for each mechanically ventilated patient.

Over the next several pages, we will walk through each question in detail, with reference to an example patient, to look at how to put all your knowledge together and ventilate a patient effectively.