ObjectiveTo evaluate the relationship between the mixed venous (S&OV0456;o2), hepatic, and femoral venous oxygen saturations before and during sympathomimetic drug infusions.DesignCase series.SettingTertiary care center.PatientsTwenty-four ICU patients: postoperative open-heart surgery patients (n = 12), patients with septic shock (n = 8), and patients with acute respiratory failure (n = 4).InterventionsIn postoperative open-heart surgery patients and patients with respiratory failure, cardiac output was increased by at least 25% following therapy with either dobutamine or dopamine. Patients with septic shock were treated with either dopamine or norepinephrine to correct hypotension.Measurements and Main ResultsVasoactive drug infusions increased cardiac index and oxygen delivery by 34% and oxygen consumption by 8%. S&OV0456;o2increased (62.6 ± 6.7% vs. 69.5 ± 6.0%,p< .001). Although cardiac index was the most important determinant of S&OV0456;o2, the correlation between cardiac index and S&OV0456;o2was weak (r2= .32). The hepatic and femoral venous saturations also increased (49.0 ± 12.1% vs. 59.4 ± 9.8%,p< .01, and 51.9 ± 16.6% vs. 63.4 ± 9.8%,p< .001, respectively) in response to vasoactive treatment. The mean gradient between S&OV0456;o2and hepatic venous saturation was 11.9 ± 8.7% and was independent of the clinical condition and baseline S&OV0456;o2. The hepatic venous oxygen saturation increased in parallel with S&OV0456;o2regardless of the initial S&OV0456;o2value.ConclusionsThe individual values of S&OV0456;o2have no predictive value concerning regional oxygen transport. The parallel increase in S&OV0456;o2and hepatic venous oxygen saturation suggests that the vasoactive treatment did not compromise splanchnic oxygenation.