Individualized Open Lung Ventilation and Postoperative Pulmonary Complications in Thoracic Surgery

Effect of Individualized Versus Standardized Open-Lung Ventilation on Postoperative Pulmonary Complications in Thoracic Surgery: A Randomized Controlled Trial

This prospective, single-center, randomized controlled trial aims to evaluate the efficacy of an intraoperative "Individualized Open Lung Ventilation" strategy compared to a standard lung-protective ventilation strategy in patients undergoing thoracic surgery.

One-lung ventilation (OLV) is essential for thoracic surgery but can cause lung injury. While standard care often uses fixed ventilation parameters, this study investigates whether personalizing Positive End-Expiratory Pressure (PEEP) to achieve the lowest driving pressure can reduce the incidence of postoperative pulmonary complications (PPCs) within 7 days after surgery.

Background: Postoperative pulmonary complications (PPCs) are a major cause of morbidity following thoracic surgery. One-lung ventilation (OLV), while necessary for surgical exposure, induces ischemia-reperfusion injury and mechanical stress. Current standard lung-protective ventilation (LPV) strategies typically employ low tidal volumes with a fixed Positive End-Expiratory Pressure (PEEP). However, fixed parameters may not account for individual variations in lung compliance and mechanics. This study hypothesizes that an individualized open lung approach, guided by driving pressure, will optimize lung mechanics and reduce clinical complications.

Study Design: This is a prospective, randomized controlled trial conducted at Aerospace Center Hospital. Eligible patients aged 18-75 undergoing elective video-assisted thoracic surgery (VATS) with an expected OLV duration of >1 hour will be enrolled.

Intervention Groups: Participants are randomized (1:1) into two groups:

Control Group (Standard Strategy): Patients receive volume-controlled ventilation during OLV with a tidal volume of 6 mL/kg predicted body weight (PBW) and a fixed PEEP of 5 cmH2O. No routine lung recruitment maneuvers are performed.

Experimental Group (Individualized Strategy): Patients receive a tidal volume of 4-6 mL/kg PBW. Upon initiating OLV, a lung recruitment maneuver is performed (PEEP increased to 10 cmH2O). Subsequently, a decremental PEEP trial is conducted (starting at 10 cmH2O and decreasing by 1 cmH2O steps) to identify the optimal PEEP level that produces the lowest driving pressure. This optimal PEEP is maintained for the duration of OLV.

Outcomes: The primary outcome is the incidence of defined Postoperative Pulmonary Complications (PPCs) within 7 days post-surgery, including pneumonia, atelectasis, ARDS, respiratory failure, and re-intubation. Secondary outcomes include intraoperative respiratory mechanics (driving pressure, compliance, oxygenation index), length of hospital stay, and other system complications.

Inclusion Criteria:

• Age 18 to 75 years.
• American Society of Anesthesiologists (ASA) physical status I-III.
• Body mass index between 18 and 30 kg/m².
• Scheduled for elective video-assisted thoracoscopic surgery (VATS).
• Expected duration of one-lung ventilation longer than 1 hour.
• Able to understand the study procedures and provide written informed consent.

Exclusion Criteria:

• Pregnancy or breastfeeding.
• Emergency surgery or reoperation.
• History of severe pulmonary disease, including chronic obstructive pulmonary disease, pulmonary fibrosis, severe emphysema, pulmonary bullae, pneumothorax, or uncontrolled asthma.
• History of heart failure or coronary artery disease.
• Previous thoracic surgery or mechanical ventilation within 1 month before surgery.
• Planned postoperative mechanical ventilation.
• Bilateral thoracic surgery.
• Participation in another interventional clinical trial.
• Conversion to open thoracotomy during surgery.