Interpolating arterial blood gas results is a tricky business and it confuses many nurses, myself included.
In an attempt to try to simplify the whole process I have produced a short video to help you get your head around it all.

Remember, I have greatly simplified the whole thing in an attempt to at least get a footing in the process. If the video does clarify things a little, you might like to follow up with some further reading on the topic.

Please let me know if this presentation was of any use to you or, alternatively,  if it confused you even further.

46 Responses to “how to read an arterial blood gas.”

  1. Thank you so much!
    Just started my NICU training and this has helped a lot!

  2. whoever done this. thank you very much it was a great help! thank you!

  3. Thank goodness someone can talk my language and make it so easy to understand. Just starting in new area of Emergency and need to go over old concepts in a basic way again, thanks so much!!

    • how to read and prepare AB gases.Thank you so much for this! I’m a third year bscmlt student who has been struggling with ABGs since year one, and your video helped me more than any textbook ever did. I finally get it!! Thank you!!!

  4. THANK YOU! I’m a fourth year in a pulmonary clinical setting with many COPD patients. I was having a very hard time wrapping my mind around ABG’s but you completely cleared it all up. Muchly appreciated!
    PS this is my first time visiting your site and I have now added it to my bookmarks. I look forward to many more wonderfully informative posts.


  5. FANTASTIC!! You made this so much easier to understand than my professor. I appreciate it!

  6. Thank you soooo much.

    So much better and clearer than listening 2 hours of lectures.

  7. many thanks for your presentation…i can read ABG now! so happy :)

  8. This was a pretty easy and simple presentation to follow. I am a student in Respiratory Therapy so I already have a good understanding of ABG’s and how they are to be read, I would recommend this presentation to someone just learning how to interpret ABG’s. The only suggestion I have is explain in a little more detail how an ABG may be either acute, partially compensated, or fully compensated. For example: it is acute if the pH is abnormal but only one of the other parameters can be abnormal; if the pH is in the normal range the ABG is either fully compensated or normal; if both parameters CO2 and HCO3- are abnormal the ABG must be either partially compensated or fully compensated it cannot be acute; for an ABG to partially compensated the pH is abnormal along with CO2 and HCO3- moving in opposite directions ( CO2 acidic and HCO3- alkalinic); and for an ABG to be fully compensated the pH must be in the normal range along with CO2 and HCO3- moving in the same direction ( CO2 acidic and HCO3- acidic). Again nice presentation.

  9. This presentatio was really good Thanxs Cheers

  10. Thanks! Awesome presentation. Clarified things for me.

  11. Oh my goodness…that was such an excellent presentation. It took a while before I got the BeeGee joke in the beginning….hahaha. I wish there were more examples… at least 5 more. I just started learning ABG’s and I am scared. I am having trouble understanding the compensation part of it….but the way you explained it really made the light bulb go off in my head. Thank you so much Ian. I totally appreciate it.

  12. Interesting feed back from various groups, as well as an interesting take on the lessons. However, in response to the doctor who blogged, I’m a student Respiratory Therapist who has never heard of the term delta, what is that?

  13. Bring on the explanation of the delta gap!!! :-)

  14. I was confused on this from my Professor’s lecture… This helped me understand how to differentiate between metabolic and respiratory and why…


  15. Thank you so much for this! I’m a third year nursing student who has been struggling with ABGs since year one, and your video helped me more than any textbook ever did. I finally get it!! Thank you!!!

  16. This was great. I always get confused with the partial and complete compensation but now I understand it. Thanks. It was a great presentation and well explained and easy to understand! :D

  17. It’s so much helpful…but if u add the causes for each its gonna be perfect
    thanx alooooooooooot ^^

  18. Thank you so much. I had a lecture on this today and was really confused. You made it a lot easier to understand.

    thank yo so much!!!!!!!!!

  19. Kvaka B: In Australia, we don’t have RTs. Instead we have more of a team approach by medical and nursing staff and our physios.

    If you are an RN that has anything to do with ventilators – ie in ED or ICU – you need to be able to interpret ABGs in order to appropriately manipulate your vent settings. The ability to interpret CXRs goes hand-in-hand with this (again, something which is traditionally thought of as something that only doctors do).

    If you are a nurse working in a medical ward, outpatients, jail, or in a nursing home, then ABG analysis isn’t too relevant – but always good to know about, though. Hope that helps.

  20. I’m confused, why would a nurse need to know blood gases? Is this common outside of USA? This is a very deep subject which most MDs cannot comprehend. At least in USA, blood gases are usually a subject that Respiratory Therapists {Respiratory Practitioners] and MDs, especially those working in critical care units have to know.

    Blood gases are often misinterpreted especially from the metabolic side, don’t even want to talk about mixed and triple disorders.

    All the best.

  21. Thanks Ian for the great video. I work on a respiratory ward, and I think this will become popular viewing, especially for the grads.

  22. Thanks Ian, a great presentation that was easy to understand

  23. really it was a very good chance for me to get this web site as the ABG was a problem for me thank you all about this grat subjedt

  24. Great Job, thanks!

  25. Thanks Ian.
    This is a great presentation, easy to understand and follow, keep up the good work

  26. I loved the presentation, but I would have liked to guess what the results of the ABG results were but the answers where already there. I enjoyed your pace it is very intersting and keeps my attention through out the whole presentation. I look forward to listening and watching more of your presentations.


  27. Thank you for taking the time to explain ABG’s. This has been an enormous help.

  28. Great explantion of basic concepts and interpretation. Thanks

  29. The presentation was great! I’m a first year nursing student, and this cleared a lot about ABGs and compensation. Thank you very much!

  30. That was great, as a 3rd year nursing student the ABG’s are a constant source of confusion and sometimes angst. Well paced and easy to understand.
    Thanks Ian

  31. Far better than going to uni where they let you just guess everything!

  32. thank you ian, the explanation is clear and has helped me to understand better…..thanx again

  33. Thanks for the reference to the Orlando guide – I found it and thought it was very helpful. The link in prn pengiun’s comment is broken (at least for me) – here’s a hopefully unbroken link. Great educational site in general. As is this blog. Thanks!

  34. I was having trouble understanding the “compensation” element of reading ABGs, but your clear explanation has helped me understand this…finally! Thanks for not making this any more difficult than it has to be.

  35. I liked that tool for ABG interpretation; I did like the pace as well as the doggy in the background.

    My only advice would be a little more substance within the HCO3- and H2CO3+ discussion. More specifically explain the reversible chemical reactions that contribute to the give and take of H+. I liked how you used the vacuum metaphor, but more expansion on the chemistry would help to reason through the differences between respiratory vs metabolic compensation.

    Thanks for the great presentation!

  36. Great pace and presentation.
    OK, being entirely new to this, I’m not sure if this is a stupid question, but do the lungs ever compensate for kidneys excreting too much bicarbonate? What does this look like in comparison with your last example?

  37. now I understand

  38. Crystal clear, especially the last part on compensation. Thanks

  39. Thanks Ian. Very helpful

  40. Thnx for the review. This will be very helpful to the newbies. Keep on keeping on, Ian.

  41. Good video Ian. Am pretty ok with ABG’s except with the partial compsenation. Was good to go over it again.

  42. I didn’t learn anything new, but this is a subject that I constantly get confused on when it comes down to that critical patient that you need to have results. Thanks for the well-organized refresher.

  43. Great presentation, which explains the interpretation of ABG results quite well. It took me a while to get my head around ABGs, but I guess it just requires practice.

    I would really recommend the 2004 Orlando guide that is referenced at the end of the presentation – when I was learning ABG interpretaion, I found this to be the easiest to follow article around. It can be found at: folder/Inter of Arterial Blood Gas.pdf (and yeah, there are spaces in the URL)

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