Utility of bronchial blocker placement in the lateral versus supine position for thoracoscopic surgery: a randomised controlled trial in China.

Background: Bronchial blocker (BB) displacement after supine placement and subsequent patient repositioning remains a significant challenge during video-assisted thoracoscopic surgery (VATS). We aimed to test the hypothesis that placing the BB in the lateral decubitus position after standard supine tracheal intubation would reduce the incidence of malposition compared to conventional supine placement. Methods: In this single-centre, prospective, randomised, single-blind, controlled trial conducted in China, 120 adult patients scheduled for VATS requiring one-lung ventilation were randomly assigned to either the Supine group (BB placed supine before turning lateral) or the Lateral group (BB placed after positioning the patient lateral). The primary outcome was the incidence of BB malposition, defined as the proportion of patients requiring BB repositioning (movement >1.0 cm) during the pre-incision fibreoptic bronchoscopic (FOB) check, assessed in the per-protocol population. The trial was registered with the Chinese Clinical Trial Registry, ChiCTR2400093699. Findings: Between Jan 13 and May 15, 2025, among 118 patients analysed per-protocol, the incidence of BB malposition was 0% (0/59) in the lateral group compared to 42.4% (25/59) in the Supine group (Firth's penalised OR 0.011, 95% CI 0.000-0.086; p < 0.001). The absolute risk reduction was 42.4% (95% CI 28.6-54.1) with a number needed to treat of 2.36 (95% CI 1.85-3.47). Regarding the safety profile, the overall incidence of lower airway injury, as assessed by post-procedural FOB examination, was identical between groups (23.7% in each group, p = 1.000). All injuries were graded as mild or moderate (mucosal oedema or congestion); no severe injuries (haemorrhage or ulceration) were observed in either group. Interpretation: Our preliminary finding show that patients undergoing VATS, placing a bronchial blocker in the definitive lateral decubitus position after standard supine intubation is a highly effective and stable strategy that virtually eliminates malposition caused by patient repositioning. This strategy not only improves the reliability of lung isolation but also offers the potential, in the future, to omit the routine pre-incision bronchoscopic check, further enhancing procedural efficiency. Future multicentre trials involving operators with varying levels of experience are needed to validate the generalisability of these findings. Funding: The Ningbo Medical and Health Brand Discipline.