The clinical trade-off of intraluminal versus extraluminal bronchial blockers in children: a retrospective analysis of respiratory mechanics and airway trauma during lung isolation preparation

Introduction Optimal bronchial blocker (BB) placement for pediatric lung isolation presents a clinical dilemma. Intraluminal placement restricts the narrow endotracheal tube (ETT) lumen, whereas extraluminal placement risks upper airway trauma. Methods This retrospective study compared adjusted respiratory mechanics and perioperative safety between intraluminal (Group I) and extraluminal (Group E) BB placement strategies in children. Primary outcomes included respiratory mechanics [peak airway pressure [Ppeak], airway resistance [Raw], and dynamic and static driving pressures [ΔPdyn, ΔPstat]] recorded during the lung isolation preparation phase prior to active one-lung ventilation (OLV). Bootstrapped multivariable linear regression was utilized to adjust for anatomical confounders, notably ETT size. Postoperative airway complications were assessed via video laryngoscopy. Results A total of 68 children under 3 years of age were included in the final analysis, with 16 in Group I and 52 in Group E. The baseline characteristics were significant differences between the two groups ( p < 0.05). After adjustment, Group I exhibited significantly worse respiratory mechanics, with profound elevations in Ppeak ( p = 0.007), Raw (p < 0.001), ΔPdyn ( p = 0.004), and ΔPstat ( p = 0.014). The elevated ΔPstat strongly suggests occult auto-PEEP driven by severe expiratory flow limitation during this preparation phase. While neither group experienced intractable hypoxemia, procedure-related upper airway mucosal injuries exclusively occurred in Group E ( n = 3). Discussion In conclusion, a critical clinical trade-off is evident in pediatric lung isolation. While intraluminal bronchial blocker placement protects glottic structures from direct trauma, it profoundly increases airway resistance and the risk of auto-PEEP during the lung isolation preparation phase. Conversely, extraluminal placement significantly optimizes respiratory mechanics; however, our study unexpectedly revealed a distinct risk of adjacent upper airway mucosal injury exclusively with this technique. This novel finding underscores the necessity for anesthesiologists to strictly individualize the choice of bronchial blocker placement, carefully balancing the imperative for optimal respiratory mechanics against the potential for airway trauma based on patient airway anatomy and pulmonary compliance.