Skip to main content
  • Poster presentation
  • Open access
  • Published:

Large venous-arterial PCO2 is associated with poor outcomes in surgical patients


This study evaluated whether a large venous-arterial CO2 gap (PCO2 gap) during the preoperative period is associated with poor surgical outcome.


A prospective observational study that included high-risk surgical patients who were 18 years of age or older. Palliative surgery, Child B and Child C cirrhosis, and class IV heart condition patients or ejection fraction <30% were excluded. The patients were divided into two groups: wide [P(v-a)CO2] versus narrow [P(v-a)CO2]. In order to determine the best value to discriminate hospital mortality, the receiver operating characteristic curve was used for the [P(v-a)CO2] values collected during the preoperative period, and the most accurate value was chosen as a cut-off to define the groups.


The study included 66 patients. The preoperative [P(v-a)CO2] value that best discriminated hospital mortality was 5.0 mmHg, area = 0.73. Preoperative patients with [P(v-a)CO2] of more than 5.0 mmHg presented a higher hospital mortality (36.4% vs. 4.5%, P = 0.004), higher prevalence of circulatory shock (56.8% vs. 22.7%, P = 0.01) and acute renal failure in the postoperative period (27.3% vs. 4.5%, P = 0.02), and longer length of hospital stays (20.0 (14.0 to 30.0) vs. 13.5 (9.0 to 25.0) days, P = 0.01). The groups did not present any differences regarding demographic and physiological data.


The PCO2 gap values of more than 5.0 mmHg in the preoperative period were associated with worse postoperative outcome.

Author information

Authors and Affiliations


Rights and permissions

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article

Silva, J., Oliveira, A., Maia, V. et al. Large venous-arterial PCO2 is associated with poor outcomes in surgical patients. Crit Care 15 (Suppl 2), P62 (2011).

Download citation

  • Published:

  • DOI: