Continuous central venous oxygen saturation assisted intraoperative hemodynamic management during major abdominal surgery: a randomized, controlled trial

BACKGROUND: Major abdominal surgery is associated with significant risk of morbidity and mortality in the perioperative period. Optimising intraoperative fluid administration may result in improved outcomes. Our aim was to compare the effects of central venous pressure (CVP), and central venous oxygen saturation (ScvO(2))-assisted fluid therapy on postoperative complications in patients undergoing high risk surgery. METHODS: Patients undergoing elective major abdominal surgery were randomised into control and ScvO(2) groups. The target level of mean arterial pressure (MAP) was ≥ 60 mmHg in both groups. In cases of MAP < 60 mmHg patients received either a fluid or vasopressor bolus according to the CVP < 8 mmHg in the control group. In the ScvO(2) group, in addition to the MAP, an ScvO(2) of <75 % or a >3 % decrease indicated need for intervention, regardless of the actual MAP. Data are presented as mean ± standard deviation or median (interquartile range). RESULTS: We observed a lower number of patients with complications in the ScvO(2) group compared to the control group, however it did not reach statistical significance (ScvO(2) group: 10 vs. control group: 19; p = 0.07). Patients in the ScvO(2) group (n = 38) received more colloids compared to the control group (n = 41) [279(161) vs. 107(250) ml/h; p < 0.001]. Both groups received similar amounts of crystalloid (1126 ± 471 vs. 1049 ± 431 ml/h; p = 0.46) and norepinephrine [37(107) vs. 18(73) mcg/h; p = 0.84]. Despite similar blood loss in both groups, the ScvO(2) group received more blood transfusions (63 % vs. 37 %; p = 0.018). More patients in the control group had a postoperative PaO(2)/FiO(2) < 200 mmHg (23 vs. 10, p < 0.01). Twenty eight day survival was significantly higher in the ScvO(2) group (37/38 vs. 33/41 p = 0.018). CONCLUSION: ScvO(2)-assisted intraoperative haemodynamic support provided some benefits, including significantly better postoperative oxygenation and 28 day survival rate, compared to CVP-assisted therapy without a significant effect on postoperative complications during major abdominal surgery. TRIAL REGISTRATION: ClinicalTrials.gov NCT02337010.