Individualized PEEP Titration on Postoperative Pulmonary Complications

Study Overview
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Brief Summary
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This study aims to investigate the effectiveness and safety of implementing a personalized positive end-expiratory pressure (PEEP) management strategy guided by esophageal pressure (Pes), as well as its potential to reduce the occurrence of postoperative pulmonary complications (PPCs) in elderly patients undergoing laparoscopic surgery.

Detailed Description
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This trial is a single-blind, randomized, controlled, multicenter study. Elderly patients undergoing laparoscopic surgery under general anesthesia will be recruited according the inclusion and exclusion criteria. Participants in this study will be randomly assigned into two groups. The total sample size will be 232, with 116 participants in the experimental group and 116 participants in the control group. A stratified block randomization method will be employed, using the ARISCAT score for PPCs risk assessment and individual study centers as stratification factors. Anesthesia routine will be applied during pre-anesthetic preparation, anesthetic induction, maintenance and emergence except intraoperative respiratory management. In the control group (PEEP Group), fixed PEEP of 3 cmH2O is applied throughout the procedure without lung recruitment maneuvers. While in the experimental group (Pes-Guided PEEP Group), continuous monitoring of end-expiratory esophageal pressure (Pes_ee) is conducted. PEEP is chosen to maintain a positive transpulmonary pressure at end-expiration (Ptp_ee = PEEP - Pes_ee) after lung recruitment. PEEP titration following lung recruitment should be performed after endotracheal intubation or any procedure that may cause lung collapse, such as pneumoperitoneum, deflation or inflation of the endotracheal tube cuff, changes in position, or endotracheal suctioning. PEEP Titration is also required every hour after the establishment of pneumoperitoneum. Patients will be followed up within 7 days after surgery to assess basic vital signs, potential postoperative pulmonary complications (PPCs). Additionally, postoperative non-respiratory complications will be evaluated.Laboratory tests, the 15-item Quality of Recovery-15 (QoR-15) questionnaire, complications within 30 days after surgery, and 90-day survival rates will also be recorded.

Official Title
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Effect of Individualized PEEP Titration on Postoperative Pulmonary Complications in Elderly Patients Undergoing Laparoscopic Surgery- A Multicenter Randomized Controlled Clinical Trial

Conditions
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Postoperative Pulmonary Complications, Positive End-expiratory Pressure, Laparoscopic Surgery, Elderly

Intervention / Treatment
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* Procedure: Pes-Guided PEEP titration


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients aged 65 years or older, of any gender. Laparoscopic surgery under general anesthesia. Anticipated duration of surgery ≥ 2 hours. Willingness to sign informed consent or provide a legally authorized representative. Exclusion Criteria: Obesity, defined as BMI ≥ 35 kg/m2. History of pulmonary surgery (of any type). History of severe chronic obstructive pulmonary disease (COPD) requiring non-invasive ventilation and/or home oxygen therapy, or systemic corticosteroid treatment for acute COPD exacerbations. Severe pulmonary arterial hypertension, defined as pulmonary artery systolic pressure > 40 mmHg. Heart failure, ongoing hemodynamic instability, or severe shock (as determined by the attending internist), cardiac index < 2.5 L/min/m2, or the requirement for positive inotropic drugs to maintain blood pressure. Severe cardiac disease (NYHA class III or IV, acute coronary syndrome, sustained ventricular tachyarrhythmias, unable to achieve > 4 METs). Severe liver or renal dysfunction (Child-Pugh score 10-15, serum creatinine ≥ 2 mg/dL, or patients requiring peritoneal dialysis or hemodialysis). Neuromuscular disease (of any type). History of bone marrow transplantation or recent use of immunosuppressive drugs (chemotherapy or radiotherapy within 2 months before surgery). Mechanical ventilation duration > 30 minutes within the past 30 days (e.g., during surgery under general anesthesia). Requirement for one-lung ventilation. History of acute respiratory distress syndrome with potential need for prolonged postoperative mechanical ventilation. Planned re-intubation after surgery. Pregnancy (excluded by medical history and/or laboratory tests). Brain injury or tumor. Requirement for prone or lateral position during surgery. Severe esophagogastric varices. Enrollment in other interventional studies or refusal to sign informed consent.

Ages Eligible for Study
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Minimum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: PEEP Group<br>After endotracheal intubation, an esophageal balloon is placed and calibrated for accurate positioning and inflation pressure. Continuous monitoring of end-expiratory esophageal pressure (Pes_ee) is conducted. Fixed PEEP of 3 cmH2O is applied throughout the procedure without lung recruitment maneuvers. | |
| Experimental: Pes-Guided PEEP Group (PEEPPtp)<br>After endotracheal intubation, an esophageal balloon is placed and calibrated for accurate positioning and inflation pressure. Continuous monitoring of end-expiratory esophageal pressure (Pes_ee) is conducted. Lung recruitment is performed at each time point. After lung recruitment, ventilation is adjusted based on the target PEEP. PEEP is chosen to maintain a positive transpulmonary pressure at end-expiration (Ptp_ee = PEEP - Pes_ee). PEEP titration following lung recruitment should be performed within 1 hour after endotracheal intubation or any procedure that may cause lung collapse, such as pneumoperitoneum, deflation or inflation of the endotracheal tube cuff, changes in position, or endotracheal suctioning. | Procedure: Pes-Guided PEEP titration<br>* Lung recruitment is performed at each time point, involving a switch from volume-controlled (VCV) mode to pressure-controlled (PCV) mode with a pressure setting of 20 cmH2O, RR of 15 bpm, I:E ratio of 1:1, FiO2 of 0.4, and PEEP of 5 cmH2O. During lung recruitment, PEEP is gradually increased in increments of 5 cmH2O, maintained for 5 respiratory cycles until PEEP reaches 20 cmH2O and airway pressure reaches 40 cmH2O, and then maintained for 10 respiratory cycles. After lung recruitment, ventilation is adjusted based on the target PEEP. Each PEEP titration should ensure adequate muscle relaxation, volume status, and hemodynamic stability. PEEP is chosen to maintain a positive transpulmonary pressure at end-expiration (Ptp_ee = PEEP - Pes_ee). Each PEEP titration should ensure adequate muscle relaxation, volume status, and hemodynamic stability.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| postoperative pulmonary complications | the incidence of postoperative pulmonary complications | day 1 to day 7 after surgery, and day 30 after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| airway peak pressure (cmH2O) | intraoperative mechanical ventilation parameters | intraoperative | 
| driving pressure (cmH2O) | intraoperative mechanical ventilation parameters | intraoperative | 
| Vt (ml) | tidal volume | intraoperative | 
| dynamic lung compliance (mL/cmH20) | Cdyn = Vt/(Ppeak - PEEP) | intraoperative | 
| PaCO2 (mmHg) | measured the partial pressure of carbon dioxide in arterial blood | intraoperative | 
| EtCO2 (mmHg) | End-tidal carbon dioxide | intraoperative | 
| PaO2/FiO2 ratio | the ratio of partial pressure of oxygen in arterial blood (PaO2) to the fraction of inspiratory oxygen concentration (FiO2) | intraoperative | 
| PaO2 (mmHg) | partial pressure of oxygen in arterial blood | intraoperative | 
| non-respiratory complications | the incidence of stroke, myocardial infarction, acute renal failure, DIC, SIRS, sepsis, septic shock, wound infection | day 1 to day 7 after surgery, and day 30 after surgery | 
| QoR-15 scores | early quality of recovery | day 1 and day 3 after surgery, the day of discharge, and day 30 after surgery | 
| unplanned reintubation | the incidence of unplanned reintubation | day 1 to day 7 after surgery | 
| unplanned transfer to the ICU | the incidence of unplanned transfer to the ICU | day 1 to day 7 after surgery | 
| duration of ICU stay | duration of ICU stay | day 1 after surgery to the day of discharge, assessed up to 90 days | 
| length of hospital stay | the number of days from a patient's hospital admission to discharge | from the day of admission to the day of discharge, assessed up to 90 days | 
| mortality rates | mortality rates | at 30 and 90 days |