Association between anesthetic fresh gas flow and postoperative inflammatory response in laparoscopic sleeve gastrectomy: A retrospective cohort study

Perioperative inflammation is associated with adverse postoperative outcomes, and anesthetic management may modulate this response. However, the influence of fresh gas flow strategies during volatile anesthesia on perioperative inflammatory responses has not been adequately characterized. Evidence in obese surgical patients remains particularly limited despite the chronic low-grade inflammatory state and exaggerated responses to surgical stress associated with obesity. In this retrospective cohort study, 155 obese adult patients undergoing laparoscopic sleeve gastrectomy under sevoflurane anesthesia were evaluated. Patients received either low-flow (1 L/min, n = 76) or standard-flow (4 L/min, n = 79) anesthesia. Perioperative changes (Δ = postoperative - preoperative) in red cell distribution width (RDW), C-reactive protein (CRP), and neutrophil-to-lymphocyte ratio (NLR) were assessed using preoperative and 24-hour postoperative values. Between-group changes in these 3 designated primary outcomes were compared, and multivariable linear regression analyses were performed as adjusted supportive analyses. Intraoperative hemodynamic and oxygenation parameters and postoperative hospital length of stay were evaluated as exploratory secondary outcomes. ΔRDW and ΔCRP were greater in the standard-flow group than in the low-flow group (both P < .001) and remained statistically significant after Bonferroni correction (α = 0.0167), whereas no statistically significant between-group difference was observed for ΔNLR (P = .902). After adjustment for the measured covariates and calendar period, standard-flow anesthesia remained associated with greater ΔRDW and ΔCRP. No statistically detectable between-group differences were observed in the longitudinal hemodynamic and oxygenation outcomes or postoperative hospital length of stay. Low-flow sevoflurane anesthesia was associated with smaller postoperative increases in RDW and CRP compared with standard-flow anesthesia in obese patients undergoing laparoscopic sleeve gastrectomy. These findings suggest an association between fresh gas flow strategy and selected postoperative inflammatory marker changes during bariatric surgery.