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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
352
Standard lung-protective ventilation is applied during one-lung ventilation. Ventilation parameters include a tidal volume of 6 mL/kg predicted body weight and a fixed positive end-expiratory pressure (PEEP) of 5 cmH2O throughout one-lung ventilation. No routine recruitment maneuver is performed during one-lung ventilation. At the end of one-lung ventilation, a standardized lung recruitment maneuver is applied before resuming two-lung ventilation.
Individualized open lung ventilation is applied during one-lung ventilation. Tidal volume is set at 4-6 mL/kg predicted body weight. After lung recruitment, a decremental PEEP trial is performed starting from 10 cmH2O, with PEEP reduced stepwise to identify the level associated with the lowest driving pressure. The selected PEEP is maintained throughout one-lung ventilation. A standardized lung recruitment maneuver is applied at the end of one-lung ventilation before resuming two-lung ventilation.
Aerospace Center Hospital
Beijing, China
Incidence of postoperative pulmonary complications within 7 days
Postoperative pulmonary complications (PPCs) occurring within 7 days after surgery, defined according to pre-specified criteria, including pneumonia, atelectasis requiring therapeutic intervention, acute respiratory distress syndrome (ARDS), respiratory failure requiring noninvasive or invasive mechanical ventilation, reintubation, or mechanical ventilation lasting longer than 48 hours.
Time frame: Within 7 days after surgery
Incidence of secondary postoperative pulmonary complications within 30 days
Secondary postoperative pulmonary complications occurring within 30 days after surgery, including mild atelectasis, pleural effusion, bronchospasm, prolonged air leak, and other pulmonary complications not meeting the criteria for primary postoperative pulmonary complications.
Time frame: Within 30 days after surgery
Intraoperative Driving Pressure
Driving pressure is calculated as the difference between Plateau Pressure and Positive End-Expiratory Pressure. Lower driving pressure indicates lung-protective ventilation. Assessments are performed at 5 predefined time points: T1 (TLV baseline after positioning), T2 (OLV 30 minutes), T3 (OLV 60 minutes), T4 (during resection), and T5 (within 15 minutes of TLV restoration).
Time frame: From the start of mechanical ventilation until 15 minutes after the restoration of two-lung ventilation.
Incidence of non-pulmonary postoperative complications
Postoperative non-pulmonary complications within 30 days after surgery, including cardiovascular, neurological, gastrointestinal, urinary, and wound-related complications.
Time frame: Within 30 days after surgery
Intraoperative Dynamic Compliance
Dynamic compliance is measured as Tidal Volume divided by (Peak Pressure - PEEP). Higher compliance suggests better lung mechanics. Data is collected at T1 (TLV baseline), T2 (OLV 30 minutes), T3 (OLV 60 minutes), T4 (during resection), and T5 (within 15 minutes of TLV restoration).
Time frame: From the start of mechanical ventilation until 15 minutes after the restoration of two-lung ventilation.
Intraoperative Peak Airway Pressure
The maximum pressure measured during the inspiratory phase of the mechanical ventilation cycle. Data is collected at 5 predefined time points: T1 (TLV baseline after positioning), T2 (OLV 30 minutes), T3 (OLV 60 minutes), T4 (during resection), and T5 (within 15 minutes of TLV restoration).
Time frame: From the start of mechanical ventilation until 15 minutes after the restoration of two-lung ventilation.
Arterial Oxygen Partial Pressure to Fractional Inspired Oxygen Ratio
Ratio of arterial oxygen partial pressure to fractional inspired oxygen, assessed by arterial blood gas analysis to evaluate oxygenation status. Assessments are performed at: T1 (TLV baseline), T2 (OLV 30 minutes), T3 (OLV 60 minutes), T4 (during resection), and T5 (within 15 minutes of TLV restoration).
Time frame: From the start of mechanical ventilation until 15 minutes after the restoration of two-lung ventilation.
Hospital Length of Stay
he total duration of hospital stay from admission to discharge.
Time frame: Participants will be followed for the duration of hospital stay, an average of 7-9 days.
Incidence of ICU Admission
Number of participants requiring admission to the Intensive Care Unit after surgery.
Time frame: From date of surgery until date of discharge, assessed up to 30 days
30-Day Mortality
All-cause mortality occurring within 30 days after surgery.
Time frame: 30 days post-surgery
Incidence of Intraoperative Hypotension
Defined as a mean arterial pressure \< 65 mmHg or a \> 20% decrease from baseline requiring vasopressor support.
Time frame: From the start of anesthesia induction until the end of surgery.
Incidence of Pneumothorax
Occurrence of pneumothorax detected postoperatively.
Time frame: Within 7 days after surgery.
Partial Pressure of Carbon Dioxide
PaCO2 levels measured by arterial blood gas analysis. Measurements correspond to 5 time points: T1 (TLV baseline), T2 (OLV 30 minutes), T3 (OLV 60 minutes), T4 (during resection), and T5 (within 15 minutes of TLV restoration).
Time frame: From the start of mechanical ventilation until 15 minutes after the restoration of two-lung ventilation.
Arterial pH
Acid-base status assessed by arterial blood gas analysis. Measurements correspond to 5 time points: T1 (TLV baseline), T2 (OLV 30 minutes), T3 (OLV 60 minutes), T4 (during resection), and T5 (within 15 minutes of TLV restoration).
Time frame: From the start of mechanical ventilation until 15 minutes after the restoration of two-lung ventilation.
Mean Arterial Pressure
Average blood pressure in an individual during a single cardiac cycle. Data is recorded at: T1 (TLV baseline), T2 (OLV 30 minutes), T3 (OLV 60 minutes), T4 (during resection), and T5 (within 15 minutes of TLV restoration).
Time frame: From the start of mechanical ventilation until 15 minutes after the restoration of two-lung ventilation.
Heart Rate
Frequency of the cardiac cycle measured in beats per minute. Data is recorded at: T1 (TLV baseline), T2 (OLV 30 minutes), T3 (OLV 60 minutes), T4 (during resection), and T5 (within 15 minutes of TLV restoration).
Time frame: From the start of mechanical ventilation until 15 minutes after the restoration of two-lung ventilation.
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