Oxygen reserve index guided fraction of inspired oxygen titration to reduce hyperoxemia during laparoscopic gastrectomy: A randomized controlled trial

Background: The usefulness of the oxygen reserve index (ORi) in reducing hyperoxemia remains unclear. We designed this study to investigate whether fraction of inspired oxygen (FiO₂) adjustment under a combination of ORi and peripheral oxygen saturation (SpO₂) guidance can reduce intraoperative hyperoxemia compared to SpO₂alone. Methods: In this prospective, double-blind, randomized controlled study, we allocated patients scheduled for laparoscopic gastrectomy to the SpO₂group (FiO₂adjusted to target SpO₂≥ 98%) or the ORi-SpO₂group (FiO₂adjusted to target 0 < 0 ORi <.3 and SpO₂≥ 98%). The ORi, SpO₂, FiO₂, arterial partial pressure of oxygen (PaO₂), and incidence of severe hyperoxemia (PaO_{2 ≥}200 mm Hg) were recorded before and 1, 2, and 3 hours after surgical incision. Data from 32 and 30 subjects in the SpO₂and ORi-SpO₂groups, respectively, were analyzed. Results: PaO₂was higher in the SpO₂group (250.31 ± 57.39 mm Hg) than in the ORi-SpO₂group (170.07 ± 49.39 mm Hg) 1 hour after incision (P <.001). PaO₂was consistently higher in the SpO₂group than in the ORi-SpO₂group, over time (P =.045). The incidence of severe hyperoxemia was higher in the SpO₂group (84.4%) than in the ORi-SpO₂group (16.7%, P <.001) 1 hour after incision. Higher FiO₂was administered to the SpO₂group [52.5 (50-60)] than the ORi-SpO₂group [40 (35-50), P <.001] 1 hour after incision. SpO₂was not different between the 2 groups. Conclusion: The combination of ORi and SpO₂guided FiO₂adjustment reduced hyperoxemia compared to SpO₂alone during laparoscopic gastrectomy.