Central venous-arterial pCO.sub.2 difference as a tool in resuscitation of septic patients

• Published in: Intensive care medicine 2013-06, Vol.39 (6), p.1034
• Main Authors: van Beest, Paul A, Lont, Mariska C, Holman, Nicole D, Loef, Bert, Kuiper, Michaël A, Boerma, E. Christiaan
• Format: Article
• Language: English
• Subjects: Septic shock
• ISSN: 0342-4642
• DOI: 10.1007/s00134-013-2888-x

To investigate the interchangeability of mixed and central venous-arterial carbon dioxide differences and the relation between the central difference (pCO.sub.2 gap) and cardiac index (CI). We also investigated the value of the pCO.sub.2 gap in outcome prediction. We performed a post hoc analysis of a well-defined population of 53 patients with severe sepsis or septic shock. Mixed and central venous pCO.sub.2 were determined earlier at a 6 h interval (T = 0 to T = 4) during the first 24 h after intensive care unit (ICU) admittance. The population was divided into two groups based on pCO.sub.2 gap (cut off value 0.8 kPa). The mixed pCO.sub.2 difference underestimated the central pCO.sub.2 difference by a mean bias of 0.03± 0.32 kPa (95 % limits of agreement: -0.62-0.58 kPa). We observed a weak relation between pCO.sub.2 gap and CI. The in hospital mortality rate was 21 % (6/29) for the low gap group and 29 % (7/24) for the high gap group; the odds ratio was 1.6 (95 % CI 0.5-5.5), p = 0.53. At T = 4 the odds ratio was 5.3 (95 % CI 0.9-30.7); p = 0.08. From a practical perspective, the clinical utility of central venous pCO.sub.2 values is of potential interest in determining the venous-arterial pCO.sub.2 difference. The likelihood of a bad outcome seems to be enhanced when a high pCO.sub.2 gap persists after 24 h of therapy.