3 years ago

Agreement between venous and arterial blood gas analysis of acid-base status in critical care and ward patients: a retrospective cohort study

Fran Priestap, Claudio M. Martin



To determine whether the use of venous blood gases can be a suitable alternative to arterial sampling to evaluate acid-base status.


The database of the clinical laboratory in a large academic hospital was searched for records of venous blood gas analysis and an arterial sample taken within ten minutes from the same patient. Bland-Altman analyses of pH, pCO2, and lactate were performed for samples obtained from patients separately from within and outside the intensive care unit (ICU).


In 2,296 paired arterial-venous samples from 351 ICU patients, the bias was 0.044, −6.2 mmHg, and −0.07 mEq·L−1 for pH, pCO2, and lactate, respectively. The range of agreement centred on this bias (upper minus lower level of agreement) was 0.134, 16.7 mmHg, and 1.35 mEq·L−1 for pH, pCO2, and lactate, respectively. Intraclass correlation coefficients (ICCs) were 0.79, 0.76, and 0.99 for pH, pCO2, and lactate, respectively, indicating excellent agreement. Multiple samples obtained from the same patient had a median standard deviation of 0.02, 2.77 mmHg, and 0.18 mEq·L−1 for pH, pCO2, and lactate, respectively. Similar agreement was observed in samples from patients outside the ICU, although the ICC was only 0.53 for pCO2.


Venous gases are suitable for initial evaluation of acid-base status in critically ill patients. Based on clinical evaluation, an arterial sample may then be considered for confirmation, and thereafter, venous blood gases could be sufficient for monitoring response to treatment.

Publisher URL: https://link.springer.com/article/10.1007/s12630-017-0951-8

DOI: 10.1007/s12630-017-0951-8

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.