[End-tidal CO2 as a predictive index of regional perfusion and its relation to aortic flow. A clinical study during...

Using a new haemodynamic monitoring system, we prospectively measured the end-tidal carbon dioxide (ETCO2) and the aortic blood flow (ABF) in 7 patients undergoing major vascular surgery to evaluate the usefulness of ETCO2 as a predictive indicator of regional blood flow. Previous studies demonstrated a high correlation between ETCO2 and Cardiac Output during CPR (r = 0.79), this allows us to conclude that ETCO2, under conditions of constant ventilation, reflects the circulatory status. We investigated the relationship between ETCO2 and ABF, and our observations confirmed that the two parameters undergo highly significant variations (p < 0.001), but low correlation was found (r = 0.15), so the increase in ETCO2 after aortic declamping depended on re-perfusion of ischaemic regions. The ETCO2 concentration increased immediately in 6 patients after declamping (p < 0.05). In 1 patient, the increase wasn't significant, but he underwent a new operation because of malfunction of the prosthesis. Our findings suggest that ETCO2 monitoring may provide clinically useful information about regional perfusion that can be used to guide therapy.