RESUMO
BACKGROUND: Controversy exists regarding the utility of continuous monitoring of mixed venous oxygen saturation (STvo2) during cardiac surgery. During a multicenter, prospective, observational study in the Department of Veterans Affairs (Cooperative Study #5), frequency of use of standard pulmonary artery catheterization (PAC) and STvo2-PAC was recorded. Here the authors relate these data to clinical outcomes. METHODS: Logistic and Cox regression models evaluating the association of PAC type with mortality, one or more postoperative complications, cardiac complications, time to extubation, and intensive care unit length of stay were constructed. The number of thermodilution cardiac outputs and arterial blood gas analyses performed in the first 24 h postoperatively were compared. RESULTS: Data from 3,265 patients undergoing myocardial revascularization (81.7%) or valve replacement-repair (18.3%) were considered. STvo2-PAC was used in 49% and PAC in 51% of patients. In the 14 hospitals, STvo2-PAC was used in all patients in four, in some patients in four, and never in six. No association of STvo2-PAC use with outcome were observed aside from unexplained hospital level effects. A small but statistically significant reduction in the number of arterial blood gas analyses (8 +/- 3 vs. 10 +/- 4, P < 0.0001, STvo2-PAC vs. PAC, respectively) and thermodilution cardiac outputs (14 +/- 8 vs. 15 +/- 9, P < 0.0001, STvo2-PAC vs. PAC, respectively) was observed with use of STvo2-PAC. CONCLUSIONS: Despite higher cost, STvo2-PAC was commonly used in this cohort. Our analysis failed to detect associations with improved outcomes aside from a small reduction in resource utilization. The precise role of STvo2-PAC remains uncertain.