Does central venous oxygen saturation-directed fluid therapy affect postoperative morbidity after colorectal surgery? A randomized assessor-blinded controlled trial.

BACKGROUND: The optimal amount and method for monitoring intravenous fluid in surgical patients is unresolved. Central venous oxygen saturation (Scvo2) has been used to guide therapy and predict outcome in high-risk and intensive-care patients. The aim of this prospective, randomized trial was to compare the rate of postoperative complications in patients receiving fluid therapy guided by Scvo2 and those treated with a traditional effluent fluid scheme. METHODS: Patients undergoing open colorectal and lower intestinal surgery (n = 241) were randomized to the Scvo2 group or the control group. The Scvo2 group received perioperatively crystalloid infusion 100 ml/h. When Scvo2 was less than 75%, a bolus of 3 ml/kg hydroxyethyl starch was given. The bolus was repeated if Scvo2 increased by 1 percentage point or more. The control group was maintained with crystalloid 800 ml/h and given extra fluid if there were clinical signs of hypovolemia. The participating surgeon, unaware of the group allocation, registered complications within day 30. RESULTS: Until 8:00 am on the first postoperative day, the Scvo2 group had received 3,869 ± 992 ml (mean ± SD) intravenous fluid compared with 6,491 ± 1,649 ml in the control group. Increase in weight was 0.8 ± 1.8 kg and 2.5 ± 1.6 kg in the two groups, respectively. The postoperative complication rate was 42% in both groups. CONCLUSION: Clinical outcomes among patients receiving Scvo2-guided perioperative fluid therapy were similar to those for patients treated with a traditional fluid regimen. Limitations in study design prevent full interpretation of these findings, and further large trials of this treatment algorithm are still required.