Tailored single-lung ventilation approaches and postoperative pulmonary outcomes in thoracic surgery

Abstract

Traditional lung-protective ventilation [low tidal volume (VT) with fixed positive end-expiratory pressure (PEEP)] reduces intraoperative lung injury but exhibits limited efficacy in preventing postoperative pulmonary complications (PPCs) following thoracic surgery requiring one-lung ventilation (OLV). This review systematically examines the multifactorial mechanisms of OLV-associated lung injury, encompassing hypoxemia [device malposition, atelectasis, ventilation/perfusion (V/Q) mismatch, impaired hypoxic pulmonary vasoconstriction (HPV)], oxidative stress, ischemia-reperfusion injury (IRI) (glycocalyx degradation, mechanical stress, inflammation), and ventilator-induced trauma (volutrauma, biotrauma). To address these limitations, we propose an open-lung protective ventilation strategy integrating alveolar recruitment maneuvers (RMs) with individualized PEEP (iPEEP) titration based on optimal respiratory compliance. Furthermore, we innovatively introduce oxygen reserve index (ORI)-guided titration of fraction of inspired oxygen (FiO₂), enabling dynamic determination of the minimum effective FiO₂ to mitigate hyperoxia-related toxicity. This synergistic "RM-iPEEP-FiO₂ triad" facilitates personalized intraoperative respiratory management by stabilizing alveoli, optimizing V/Q matching, and minimizing oxidative stress, thereby significantly reducing PPCs risk compared to conventional fixed-parameter approaches. Current limitations include insufficient multicenter validation, technical dependency on advanced monitoring/ventilators, and lack of subgroup analyses for high-risk populations. Future research should prioritize multicenter randomized controlled trials to establish universal thresholds for tailored parameters. Integration of artificial intelligence (AI) for real-time respiratory mechanics analysis and multimodal imaging is essential to refine precision thresholds. Ultimately, this strategy aims to establish an evidence-based, precision perioperative ventilation framework that optimizes clinical outcomes in thoracic surgical patients by overcoming the constraints of standardized ventilation protocols.

Keywords: One-lung ventilation (OLV); lung injury; mechanical ventilation; postoperative pulmonary complications (PPCs); tailored lung protective ventilation strategies.

Figure 1

Factors contributing to hypoxemia during OLV. (I) Ventilator malposition causing hypoventilation. (II) Collapse of non-ventilated lung and partial atelectasis in ventilated lung. (III) V/Q mismatch due to redistribution of ventilation and perfusion caused by body position and other factors. (IV) HPV regulated by various factors. HPV, hypoxic pulmonary vasoconstriction; OLV, one-lung ventilation; RV, right ventricle; V/Q, ventilation/perfusion.

Figure 2

IRI in pulmonary vascular endothelial cells. ① Reperfusion increases fluid shear stress to directly damage endothelial cells, leading to glycocalyx shedding. ② Reperfusion induces ROS storm generation in endothelial cells and leukocytes, causing glycocalyx shedding. ③ Reperfusion activates Ca²⁺ channels in endothelial cells, increases Ca²⁺ influx, and triggers cytokine storm, resulting in glycocalyx shedding. Reperfusion activates the NF-κB signaling pathway, enhances TNF-α transcription, and consequently leads to glycocalyx shedding. IRI, ischemia-reperfusion injury; NF-κB, nuclear factor-κB; ROS, reactive oxygen species; TNF, tumor necrosis factor.

Figure 3

Implementation steps of tailored OLV. (I) Optimize ventilator positioning prior to OLV. (II) The RM serves as the first step in tailored intraoperative lung opening strategy, facilitating re-expansion of atelectatic lungs. (III) Titration of tailored PEEP constitutes the second step in tailored intraoperative lung opening strategy, maintaining alveolar stability. (IV) Implement individualized inspired oxygen concentration titration based on ORI, establishing the minimum effective FiO₂ to mitigate hyperoxic injury. BB, bronchial blocker; DLT, double-lumen endotracheal tube; FiO₂, fraction of inspired oxygen; OLV, one-lung ventilation; ORI, oxygen reserve index; PEEP, positive end-expiratory pressure; RM, recruitment maneuver.

Figure 4

Implementation process of the alveolar RM. Starting with a baseline PEEP of 5 cmH₂O (or current adjusted value), incrementally increase in 5 cmH₂O steps to 10, 15, and 20 cmH₂O (may be appropriately elevated in special cases such as obesity, Trendelenburg position, or robotic surgery), maintaining each level for 3–5 respiratory cycles. Ultimately, maintain an opening pressure of 40 cmH₂O for 30 seconds to complete lung recruitment. PEEP, positive end-expiratory pressure; RM, recruitment maneuver.

Figure 5

Tailored PEEP titration. After lung RMs, select volume control mode while maintaining parameters including VT and inspiratory-to-expiratory ratio consistent with baseline settings. The initial PEEP is set based on patient characteristics such as lung compliance and BMI (16 cmH₂O for healthy individuals, 18–20 cmH₂O for obese patients or those undergoing laparoscopic surgery). Gradually decrease PEEP in 2 cmH₂O increments while maintaining for 3–5 respiratory cycles. Monitor compliance reductions >10% or changes in oxygenation indices to determine closing pressure, ultimately identifying the optimal PEEP value. Obese populations require PEEP >15 cmH₂O, while laparoscopic surgeries or Trendelenburg positioning necessitate 10–15 cmH₂O, and healthy populations typically require approximately 5–10 cmH₂O. BMI, body mass index; PEEP, positive end-expiratory pressure; RM, recruitment maneuver; VT, tidal volume.