Asked 1 Nov 2019
Does the measurement of venoarterial delta PCO2 give an indicator of the prognostic outcome?
Initial Q: Outcome of venoarterial delta PCO2 measurement in critically ill patients
2 answers
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- Answered 2 Nov 2019 Conflict of interest declaration: None Delta PCO2 appears to be difference in CO2 tension between venous and arterial blood [1]. It appears to be little studied, as referenced by few results in PubMed [2]. We have found some references… “A large Venous-Arterial PCO2 Is Associated with Poor Outcomes in Surgical Patients” was published in 2011 [3] and concludes: “The PCO2 gap values more than 5.0 mmHg preoperatively were associated with worse postoperatively outcome.” A more recent (2016) paper “Use of venous-to-arterial carbon dioxide tension difference to guide resuscitation therapy in septic shock” [4], reporting: “Because high blood lactate levels is not a discriminatory factor in determining the source of that stress, an increased ΔPCO2 (> 6 mmHg) could be used to identify patients who still remain inadequately resuscitated. Monitoring the ΔPCO2 from the beginning of the reanimation of septic shock patients might be a valuable means to evaluate the adequacy of cardiac output in tissue perfusion and, thus, guiding the therapy.” Finally, a 2016 blog article “pCO2 gap” [5] appears useful. The overview being: “pCO2 gap is a surrogate for cardiac output pCO2 gap = PcvCO2 – PaCO2 pCO2 gap >6 mmHg suggests a persistent shock state that may be amenable to fluid resuscitation +/- intrope support a 'ScvO2-cvaCO2gap-guided protocol' has been proposed by Vallet et al (2013) to guide the management of septic shock” The Vallet paper [6], as with all the papers above, is available as full-text via the links below References 1) https://www.ncbi.nlm.nih.gov/pubmed/9361343 2) https://www.ncbi.nlm.nih.gov/pubmed/?term=%22Venoarterial+CO2+gradient%22+OR+%22Delta+PCO2%22+OR+%22Veno+arterial+CO2+gradient%22 3) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3189458/ 4) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4733455/ 5) https://litfl.com/pco2-gap/ 6) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3732761/
- Answered 3 Nov 2019 Conflict of interest declaration: None Via Twitter we got some more input (see https://twitter.com/jopo899/status/1190780237602283521) this linked to a new document: "Prognostic significance of central venous-to-arterial carbon dioxide difference during the first 24 hours of septic shock in patients with and without impaired cardiac function" https://bjanaesthesia.org/article/S0007-0912(17)33289-0/fulltext And that then led to this document "Interpretation of venous-to-arterial carbon dioxide difference in the resuscitation of septic shock patients" http://jtd.amegroups.com/article/view/27528/html