Central venous–arterial CO pressure difference in correlation to dynamic changes of serum lactate level in patients with polytrauma

Background and aim of work
Early diagnosis, rapid intervention, and correction of tissue hypoperfusion are the major aims in the management of polytraumatized patients. The venous-to-arterial carbon dioxide tension difference is a marker of the adequacy of cardiac output to global metabolic demand, and so, its detection is a helpful method to determine patients who stay under resuscitation way. Regarding this, its monitoring could help the physicians to make the decision to give treatment targeting at improving cardiac output.
Patients and methods
This is a prospective single-center observational study done on 40 patients with polytrauma admitted to Assiut University Hospital resuscitation room and followed for the first 12 h of ICU stay. At the start of resuscitation, central venous and arterial blood samples were obtained to estimate the mixed venous-to-arterial carbon dioxide tension difference from the baseline values. All consecutive paired blood samples were collected for each studied patient within the following first hour, after the sixth hour, and after the 12 hour.
Other data collection
Hourly urine output during the early 12 h, kidney function, and hemodynamics of arterial carbon dioxide tension, arterial oxygen tension, central venous carbon dioxide tension, and central venous oxygen tension were assessed. Arterial oxygen saturation and mixed venous oxygen saturation, arterial and central venous lactate, hemoglobin concentration, and ICU stay were examined as well.
Results
The differences between arterial tenson and oxygen tension showed insignificant differences. There were changes in the mixed venous-to-arterial carbon dioxide tension difference over time period. Comparison between basal value and the follow-up results showed insignificant difference as well. There was significant difference between baseline lactate level and its corresponding measure at the 12 hour after resuscitation reflecting to somewhat optimal resuscitation. The hemodynamic changes (increases) over time included mean arterial blood pressure and central venous pressure. There were significant changes during the whole follow-up period in comparison with the baseline values. Urine output showed significant increases over time when compared with the second hour urine volume. There is significant correlation between blood lactate level and the difference between venous and arterial oxygen after 6 h of resuscitation; this was a strong positive correlation. The difference between blood lactate level and the difference between venous and arterial carbon dioxide is statistically significant at the baseline of resuscitation there is a moderate positive correlation.
Conclusion
Central venous–arterial carbon dioxide pressure difference in correlation to dynamic changes of serum lactate could be used as an indicator of tissue perfusion in patients with polytrauma.