Limb remote ischemic preconditioning attenuates biomarkers of acute lung injury and inflammation during thoracoscopic lobectomy: a randomized controlled trial

• Limb RIPC decreases plasma CC16, a key biomarker of lung epithelial injury. • RIPC attenuates systemic Inflammation (IL-6) and oxidative stress (MDA). • A simple, non-invasive intervention for molecular lung protection. • No short-term improvement in oxygenation indices was observed postoperatively. One-Lung Ventilation (OLV), though essential for thoracic surgery, triggers inflammation and oxidative stress that may lead to Acute Lung Injury (ALI). Remote Ischemic Preconditioning (RIPC) is a simple, non-invasive intervention that may activate protective pathways and reduce ischemia-reperfusion injury. This randomized controlled trial assessed whether limb RIPC attenuates OLV-induced lung injury during thoracoscopic lobectomy. Fifty-four patients undergoing thoracoscopic lobectomy with OLV were randomized to the RIPC ( n = 27) or Control (NC, n = 27) group. RIPC consisted of five cycles of 5-min ischemia and 5-min reperfusion using a lower limb tourniquet before OLV. Blood samples were collected at T0 (post-induction), T1 (30-min after OLV), T2 (90-min after OLV), and T3 (30-min after resumption two-lung ventilation). The primary endpoint was plasma CC16. Secondary endpoints included IL-6, MDA, arterial blood gases, Intraoperative Oxygenation Indices (OI, RI, A-aDO 2 , a/A), and hospital stay. Plasma CC16, IL-6, and MDA levels were significantly lower in the RIPC group from T1 to T3 (all p < 0.001). In contrast, oxygenation indices, blood gas parameters, and hospital stay did not differ significantly between groups (all p > 0.05). Limb RIPC effectively reduced systemic markers of lung injury (CC16), inflammation and oxidative stress during OLV but not in short-term improvements in oxygenation or clinical recovery. These findings suggest that RIPC confers molecular protection, with potential functional benefits requiring longer follow-up or evaluation in high-risk populations. Larger multicenter trials are warranted.