Two-Lung Ventilation Attenuates Systemic Inflammatory and Oxidative Stress Responses During Thoracic Surgery: A Randomized Clinical Trial

Objectives: To evaluate whether two-lung ventilation (TLV) attenuates perioperative inflammatory and oxidative responses compared with one-lung ventilation (OLV). Design: This was a randomized, open-label clinical trial Setting: Thoracic Surgery Department of a general hospital in Southern Brazil.Participants: Forty adults (18 years) undergoing thoracic surgery between July and November 2023 were enrolled.Exclusion criteria included pregnancy, preoperative mechanical ventilation, American Society of Anesthesiologists class IV status, inability to place a double-lumen tube, and prior lung resection.Interventions: Patients were randomized to receive OLV or TLV during surgery.Measurements & Main Results: Bronchoalveolar lavage (BAL) from the operated and non-operated lungs and plasma samples were collected pre-and postoperatively.Cytokines (IL-6, IL-1, IL-8, IL-4, IL-10, TNF-) and oxidative stress markers (TBARS, protein carbonyls, DCFH) were quantified.Group-by-time effects were analyzed using generalized mixed-effects models adjusted for age, sex, and surgical duration.BAL cytokine levels, including the primary outcome IL-6 (p= p=0.57), did not differ between groups.However, TLV was associated with reduced postoperative IL-1 (p=0.04) and oxidative damage (p=0.02) in the operated lung.Systemically, TLV markedly attenuated inflammatory and oxidative responses, with lower circulating cytokines and oxidative stress markers and significant group-by-time interactions for multiple mediators.Conclusions: Although TLV did not modify local IL-6 concentrations, it consistently dampened systemic inflammatory and oxidative activation induced by thoracic surgery, supporting its potential as a protective perioperative ventilatory strategy.