Effects of lowering inspiratory oxygen fraction during microvascular decompression on postoperative gas exchange: A pre-post study

• Published in: PloS one Vol. 13; no. 11; p. e0206371
• Main Authors: Park, Jungchan, Min, Jeong Jin, Kim, So Jin, Ahn, Jin Hee, Kim, Keoungah, Lee, Jong-Hwan, Park, Kwan, Chung, Ik Soo
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.11.2018; Public Library of Science (PLoS)
• Subjects: Anesthesia; Anesthesiology; Biology and Life Sciences; Clinical trials; Decompression; Electronic health records; Gas exchange; Gastrointestinal surgery; Infections; Medical records; Medicine; Medicine and Health Sciences; Microvasculature; Nausea; Oxygen; Pain; Patients; Physical Sciences; Research and Analysis Methods; Respiration; Review boards; Surgery; Ventilators; Vomiting
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0206371

Despite many previous studies, the optimal oxygen fraction during general anesthesia remains controversial. This study aimed to evaluate the effects of lowering intraoperative fraction of inspired oxygen on postoperative gas exchange in patients undergoing microvascular decompression (MVD). We conducted a pre-post study to compare postoperative gas exchange with different intraoperative oxygen fractions. From April 2010 to June 2017, 1456 consecutive patients who underwent MVD were enrolled. Starting in January 2014, routine oxygen fraction was lowered from 1.0 to 0.3 during anesthetic induction/awakening and from 0.5 to 0.3 during anesthetic maintenance. Postoperative gas exchange, presented as the minimum value of PaO2/FIO2 ratio within 48 hours, were compared along with adverse events. Among 1456 patients, 623 (42.8%) patients were stratified into group H (high FIO2) and 833 (57.2%) patients into group L (low FIO2). Intraoperative positive end-expiratory pressure was used in 126 (15.1%) patients in group H and 90 (14.4%) patients in group L (p = 0.77).The minimum value of PaO2/ FIO2 ratio within 48 hours after surgery was significantly greater in the group L (226.13 vs. 323.12; p < 0.001) without increasing any adverse events. In patients undergoing MVD, lowering routine FIO2 and avoiding 100% O2 improved postoperative gas exchange.