Effect of Intraoperative Goal-Directed Fluid Management on Tissue Oxygen Tension in Obese Patients: a Randomized Controlled Trial

BACKGROUND: Perioperative subcutaneous tissue oxygen tension (PsqO(2)) is substantially reduced in obese surgical patients. Goal-directed fluid therapy optimizes cardiac performance and thus tissue perfusion and oxygen delivery. We therefore tested the hypothesis that intra- and postoperative PsqO(2) is significantly reduced in obese patients undergoing standard fluid management compared to goal-directed fluid administration. METHODS: We randomly assigned 60 obese patients (BMI ≥ 30 kg/m(2)) undergoing laparoscopic bariatric surgery to receive either esophageal Doppler-guided goal-directed fluid management or conventional fluid treatment. Our primary outcome parameter was intra- and postoperative PsqO(2) measured with a polarographic electrode in the subcutaneous tissue of the upper arm. A random effects linear regression model was used to analyze the effect of intervention. RESULTS: Overall, mean (± SD) PsqO(2) was significantly higher in obese patients receiving goal-directed therapy compared to conventional fluid therapy (65.8 ± 28.0 mmHg vs. 53.7 ± 21.7, respectively; repeated measures design adjusted difference: 13.0 mmHg [95% CI 2.3 to 23.7; p = 0.017]). No effect was seen intraoperatively (69.6 ± 27.9 mmHg vs. 61.4 ± 28.8, difference: 9.7 mmHg [95% CI -3.8 to 23.2; p = 0.160]); however, goal-directed fluid management improved PsqO(2) in the early postoperative phase (63.1 ± 27.9 mmHg vs. 48.4 ± 12.5, difference: 14.5 mmHg [95% CI 4.1 to 24.9; p = 0.006]). Intraoperative fluid requirements did not differ between the two groups. CONCLUSIONS: Goal-directed fluid therapy improved subcutaneous tissue oxygenation in obese patients. This effect was more pronounced in the early postoperative period. CLINICAL TRIAL NUMBER AND REGISTRY: The study was registered at ClinicalTrials.gov (NCT 01052519).